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Title:
SYSTEM AND METHOD FOR REDUCING EFFECTS OF SPREADING FORCES DURING 3D PRINTING
Document Type and Number:
WIPO Patent Application WO/2019/136222
Kind Code:
A1
Abstract:
An additive manufacturing system (250), and corresponding method, prints a part (10) in a coupled arrangement with an anchoring component (24) in a powder bed (20) using a 3D printing system (250). The system forms the anchoring component (24) with a feature that provides a resistive force to a spreading force (12) imposed by a spreading mechanism (15) of the 3D printing system (250). The coupled arrangement in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part (10) to resist the spreading force (12), thereby reducing at least one defect in the part (10). The anchoring component (24) may be a sacrificial component or another part. Another part may be employed as the anchoring component to use fewer sacrificial components to reduce waste of powder material and fluid, the fluid employed to cause binding of the powder material.

Inventors:
HUDELSON, George (35 Rogers Street, Billerica, MA, 01862, US)
LEGENDRE, Alexander Nicholas (63 Stearns Road, Boston, MA, 02132, US)
WIEBE, Kelvin (12 Linden Street, Chelmsford, MA, 01824, US)
Application Number:
US2019/012309
Publication Date:
July 11, 2019
Filing Date:
January 04, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
DESKTOP METAL, INC. (63 Third Avenue, Burlington, MA, 01803, US)
International Classes:
B33Y10/00; B29C64/165; B29C64/40
Domestic Patent References:
WO2017040458A12017-03-09
Foreign References:
US20170312822A12017-11-02
US20140300017A12014-10-09
US20160075084A12016-03-17
US20170173891A12017-06-22
US20170225227A12017-08-10
US7291242B22007-11-06
Other References:
KHOSHNEVIS ET AL.: "Metallic part fabrication using selective inhibition sintering (SIS", RAPID PROTOTYPING JOURNAL, vol. 18, no. 2, 2012, pages 144 - 153
Attorney, Agent or Firm:
SHAH, Elizabeth (Bookoff McAndrews, PLLC2020 K Street, NW,Suite 40, Washington DC, 20006, US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. An additive manufacturing method, the method comprising:

printing an anchoring component using a three-dimensional (3D) printing system, the 3D printing system including (i) a spreading mechanism for spreading unbound powder to form layers of a powder bed and (ii) a printing mechanism for jetting fluid into the unbound powder to form the anchoring component, the anchoring component formed with a feature that provides a resistive force to a spreading force imposed by the spreading mechanism during the spreading; and

printing a part with the 3D printing system in a coupled arrangement with the anchoring component, the coupled arrangement in combination with the resistive force being sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part.

2. The method of Claim 1, wherein the feature of the anchoring component is a given number of printed layers.

3. The method of Claim 1, wherein the feature of the anchoring component is an inverse geometric feature that complements a geometric feature of the part.

4. The method of Claim 3, wherein the feature of the anchoring component is a

combination of (i) the inverse geometric feature that complements the geometric feature of the part and (ii) a given number of printed layers for the anchoring component.

5. The method of Claim 1, wherein the part and the anchoring component are coupled in the coupled arrangement via an indirect anchor coupling formed of unbound powder.

6. The method of Claim 1, wherein printing the part includes printing at least a portion of the part above the anchoring component; wherein the part and the anchoring component are coupled in the coupled arrangement via a direct anchor coupling; and wherein the method further comprises forming the direct anchor coupling by spreading one or more layers of the unbound powder and jetting fluid into same in a manner that creates a multi-point connection between the at least a portion of the part and the anchoring component.

7. The method of Claim 1, wherein printing the part includes printing at least a portion of the part above the anchoring component; wherein the part and the anchoring component are coupled in the coupled arrangement via a direct anchor coupling formed of an anti-sintering agent; and wherein the method further comprises:

applying the anti-sintering agent to a surface of the anchoring component to form a separation layer between the at least a portion of the part and the anchoring component; and

decoupling the anchoring component from the part via sintering of the coupled arrangement.

8. The method of Claim 1, wherein printing the part includes printing at least a portion of the part above the anchoring component and wherein the at least a portion of the part is the entire part.

9. The method of Claim 1, wherein printing the anchoring component includes: printing the anchoring component with a component shape that extends laterally beyond a lateral boundary of the part; printing one or more layers of the anchoring component and the part to extend the anchoring component and the part vertically upward and alongside each other; or a combination thereof.

10. The method of Claim 1, wherein printing the anchoring component includes creating the anchoring component with one or more gaps of the unbound powder, the one or more gaps facilitating decoupling of the anchoring component from the part and causing the anchoring component to be split into multiple bodies.

11. The method of Claim 1, wherein printing the anchoring component includes jetting the fluid into the unbound powder in a manner that prints the anchoring component as a multi -member structure.

12. The method of Claim 1, wherein printing the anchoring component includes printing multiple anchoring components each having a direct or indirect anchor coupling with a respective anchoring component-facing surface of the part.

13. The method of Claim 1, wherein the part has a part shape and wherein printing the anchoring component includes printing the anchoring component with a

complementary shape relative to the part shape, the complementary shape conforming to a topography of the part shape to provide for the coupled arrangement.

14. The method of Claim 1, further comprising creating a 3D computer-aided design (CAD) model of the coupled arrangement by:

duplicating a 3D model for the part to produce a copy of the 3D model of the part;

translating the copy in a given direction to produce a translated copy;

performing a 3D Boolean subtraction to subtract the 3D model of the part from the translated copy to produce a 3D model of the anchoring component; and applying an offset between the 3D model of the part and the 3D model of the anchoring component, wherein the part and the anchoring component are printed according to the 3D model of the part and the 3D model of the anchoring component, respectively.

15. The method of Claim 1, further comprising creating a 3D CAD model of the coupled arrangement by:

approximating surfaces of a 3D model of the part to produce an approximated version with a given shape, the given shape including a larger volume, lower surface area, or combination thereof, relative to a volume and surface area of the part;

translating the approximated version in a given direction to produce a translated approximated version; and performing a 3D Boolean subtraction to subtract the approximated version from the translated approximated version to produce a 3D model of the anchoring component, wherein the part and the anchoring component are printed according to the 3D model of the part and 3D model of the anchoring component.

16. The method of Claim 1, wherein printing the anchoring component includes jetting fluid at a first saturation level, wherein printing the part includes jetting fluid at a second saturation level, and wherein the first saturation level is lower relative to the second saturation level.

17. An additive manufacturing system, the system comprising:

a spreading mechanism;

a printing mechanism; and

a controller, the controller configured to (i) drive the spreading mechanism to spread unbound powder to form layers of a powder bed and (ii) drive the printing mechanism to jet fluid into the unbound powder to print an anchoring component and a part, the controller further configured to drive the printing mechanism to:

form the anchoring component with a feature that provides a resistive force to a spreading force imposed by the spreading mechanism during the spreading; and

print the part in a coupled arrangement with the anchoring component, the coupled arrangement in combination with the resistive force being sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part.

18. The system of Claim 17, wherein the feature of the anchoring component is a given number of printed layers.

19. The system of Claim 17, wherein the feature of the anchoring component is an inverse geometric feature that complements a geometric feature of the part.

20. The system of Claim 19, wherein the feature of the anchoring component is a combination of (i) the inverse geometric feature that complements the geometric feature of the part and (ii) a given number of printed layers for the anchoring component.

21. The system of Claim 17, wherein the part and the anchoring component are coupled in the coupled arrangement via an indirect anchor coupling formed of unbound powder.

22. The system of Claim 17, wherein the controller is further configured to drive the printing mechanism to print at least a portion of the part above the anchoring component; wherein the part and the anchoring component are coupled in the coupled arrangement via a direct anchor coupling; and wherein the controller is further configured to form the direct anchor coupling by driving the spreading mechanism to spread one or more layers of the unbound powder and driving the printing mechanism to jet fluid into same in a manner that creates a multi-point connection between the at least a portion of the part and the anchoring component.

23. The system of Claim 17, wherein the controller is further configured to drive the printing mechanism to print at least a portion of the part above the anchoring component; wherein the part and the anchoring component are coupled in the coupled arrangement via a direct anchor coupling formed of an anti-sintering agent; wherein the system further comprises a sintering mechanism; and wherein the controller is further configured to:

drive the printing mechanism to apply the anti-sintering agent to a surface of the anchoring component to form a separation layer between the at least a portion of the part and the anchoring component; and

drive the sintering mechanism to sinter the coupled arrangement to decouple the at least a portion of the part from the anchoring component.

24. The system of Claim 17, wherein the controller is further configured to drive the printing mechanism to print at least a portion of the part above the anchoring component and wherein the at least a portion of the part is the entire part.

25. The system of Claim 17, wherein the controller is further configured to: drive the printing mechanism to print the anchoring component with a component shape that extends laterally beyond a lateral boundary of the part; print one or more layers of the anchoring component and the part that extend the anchoring component and the part vertically upward and alongside each other; or a combination thereof.

26. The system of Claim 17, wherein the controller is further configured to drive the printing mechanism to create the anchoring component with one or more gaps of the unbound powder to facilitate decoupling of the anchoring component from the part and causing the anchoring component to be split into multiple bodies.

27. The system of Claim 17, wherein the controller is further configured to drive the printing mechanism to jet the fluid into the unbound powder in a manner that prints the anchoring component as a multi-member structure.

28. The system of Claim 17, wherein the controller is further configured to drive the printing mechanism to print the anchoring component as multiple anchoring components each having a direct or indirect anchor coupling with a respective anchoring component-facing surface of the part.

29. The system of Claim 17, wherein the part has a part shape and wherein the controller is further configured to drive the printing mechanism to print the anchoring component with a complementary shape relative to the part shape, the complementary shape conforming to a topography of the part shape to provide for the coupled arrangement.

30. The system of Claim 17, wherein the controller is further configured execute

instructions or interpret codes that were generated according to a 3D computer-aided design (CAD) model to drive the printing mechanism to print the anchoring component and the part in the coupled arrangement.

31. The system of Claim 17, wherein the controller is further configured to drive the printing mechanism to:

print the anchoring component by jetting fluid at a first saturation level; and print the part by jetting fluid at a second saturation level, wherein the first saturation level is lower relative to the second saturation level.

32. A non-transitory computer-readable medium, the non-transitory computer-readable medium having encoded thereon a sequence of instructions which, when loaded and executed by at least one processor, causes a three-dimensional (3D) printing system to:

drive a spreading mechanism of the 3D printing system to spread unbound powder to form layers of a powder bed and drive a printing mechanism of the 3D printing system to jet fluid into the unbound powder to print an anchoring component and a part, the sequence of instructions further causing the 3D printing system to drive the printing mechanism to:

form the anchoring component with a feature that provides a resistive force to a spreading force imposed by the spreading mechanism during the spreading; and

print the part in a coupled arrangement with the sacrificial component, the coupled arrangement in combination with the resistive force being sufficient to at least partially immobilize each printed layer of the part in the powder bed to resist the shear force imposed by the spreading mechanism during spreading of the unbound powder above each printed layer of the part.

33. A computer-implemented method for producing commands to drive a three- dimensional (3D) printing system, the method comprising:

producing a 3D computer-aided design (CAD) model of an anchoring component as a function of a 3D CAD model of a part, the model of the anchoring component including a feature that provides a resistive force to a spreading force imposed by a spreading mechanism of the 3D printing system; and

producing commands as a function of the model of the part and the model of the anchoring component, the commands, when followed by the 3D printing system, causing the spreading mechanism to spread unbound powder to form layers of a powder bed and causing a printing mechanism of the 3D printing system to jet fluid into layers of the unbound powder to print the part in a coupled arrangement with the anchoring component formed with the feature, the coupled arrangement in

combination with the resistive force being sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part.

34. The method of Claim 33, wherein the feature of the anchoring component is: a given number of printed layers, an inverse geometric feature that complements a geometric feature of the part, or a combination thereof.

35. The method of Claim 33, wherein producing the model of the anchoring component includes:

duplicating the model of the part to produce a copy of the model of the part; translating the copy in a given direction to produce a translated version of the copy;

performing a 3D Boolean subtraction to subtract the copy from the translated version to produce the 3D model of the anchoring component; and

applying an offset between the 3D model of the part and the 3D model of the anchoring component.

36. The method of Claim 33, wherein producing the model of the anchoring component includes:

approximating edges and surfaces of the model of the part to produce an approximated version of the part, the given shape including a larger volume, lower surface area, or combination thereof, relative to a volume and surface area of the part; translating the approximated version in a given direction to produce a translated version of the approximated version; and

performing a 3D Boolean subtraction to subtract the approximated version from the translated version to produce the 3D model of the anchoring component.

37. A computer-implemented method for scheduling printer instructions in a three- dimensional (3D) printing system, the method comprising: identifying, from a plurality of 3D computer-aided design (CAD) models, at least one part of a plurality of parts as an anchoring component for at least one other part of the plurality of parts, the anchoring component including a feature that provides a resistive force to a spreading force imposed by a spreading mechanism during spreading of unbound powder of a powder bed; and

converting the models to printer instructions to cause printing of the anchoring component with the at least one other part in a coupled arrangement with the anchoring component, the coupled arrangement in combination with the resistive force being sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism.

38. The computer-implemented method of Claim 37, wherein the identifying is

performed, dynamically, as models are received by the scheduler.

39. The computer-implemented method of Claim 37, further comprising transmitting the printer instructions to a printer mechanism of the 3D printing system, the transmitting causing the printer mechanism to jet binder fluid into the unbound powder to print the at least one part to serve as the anchoring component for the at least one other part in the coupled arrangement.

Description:
System and Method for Reducing Effects of Spreading Forces During 3D Printing

RELATED APPLICATION

[0001] This application is a continuation-in-part of ET.S. Application No. 15/971,541, filed May 4, 2018, which claims the benefit of ET.S. Provisional Application No. 62/614,132, filed January 5, 2018. The entire teachings of the above applications are incorporated herein by reference.

BACKGROUND

[0002] Binder jetting is an additive manufacturing technique based on the use of a liquid agent to join particles of a powder material, also referred to interchangeably herein as powder, to form a three-dimensional (3D) object (also referred to interchangeably herein as a “part”). In particular, a controlled pattern of the liquid agent may be applied to successive layers of the powder material in a powder bed such that the layers of the powder material adhere to one another to form the 3D object. Through subsequent processing, such as sintering, the 3D object may be formed into a finished object that may be referred to as a finished 3D part.

SUMMARY

[0003] According to an example embodiment, an additive manufacturing method may comprise printing an anchoring component using a three-dimensional (3D) printing system. The 3D printing system may include (i) a spreading mechanism for spreading unbound powder to form layers of a powder bed and (ii) a printing mechanism for jetting fluid into the unbound powder to form the anchoring component. It should be understood that the term “unbound,” as used herein, refers to powder that does not have fluid applied that would cause the powder to be bound. Further, it should be understood that while“bound” powder has fluid applied that causes the powder to be bound, such“bound” powder may not yet be cured, such as through a crosslinking reaction or other chemical process. The anchoring component is formed with a feature that provides a resistive force to a spreading force imposed by the spreading mechanism during the spreading. The method may comprise printing a part with the 3D printing system in a coupled arrangement with the anchoring component. An alternative way of thinking about the resistive force is that it reduces mobility of the printed part in the powder bed. The coupled arrangement in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part.

[0004] The feature of the anchoring component may be a given number of printed layers, an inverse geometric feature that complements a geometric feature of the part, or a combination thereof. For example, the inverse geometric feature may complement the geometric feature in that it may have a complementary shape that enables the inverse geometric feature of the anchoring component to fit together, exactly or approximately, with the geometric feature of the part such that a given resistive force for the part is achieved by way of the anchoring component and its complementary shape, thereby producing the part with no or substantially no effects from the spreading force of the spreading mechanism.

[0005] The part and the anchoring component may be coupled in the coupled

arrangement via an indirect anchoring component coupling (also referred to interchangeably herein as an indirect“anchor coupling” for simplicity) that is formed of unbound powder. Alternatively, a direct anchor coupling may be employed in the form of at least one post, for example, that is formed during printing, wherein the at least one post extends from the anchoring component to the part. According to an example embodiment, the direct anchor coupling could be partially or completely undried binder fluid that connects the part with the anchoring component. As such, the anchor coupling may result from capillary forces that couple the part to the anchoring component. The anchor coupling, which may be either direct or indirect, may be any suitable coupling between the anchoring component and part that couples the anchoring component and part, mechanically, either directly or indirectly.

Alternative example embodiments of the indirect and direct anchor coupling are disclosed further below.

[0006] Printing the part may include printing at least a portion of the part above the anchoring component. As mentioned above, the part and the anchoring component may be coupled in the coupled arrangement via a direct anchor coupling. The method may further comprise forming the direct anchor coupling by spreading one or more layers of the unbound powder and jetting fluid into same in a manner that creates a multi -point connection between the at least a portion of the part and the anchoring component, wherein the multi-point connection includes a plurality of contact points that are not contiguous.

[0007] Printing the part may include printing at least a portion of the part above the anchoring component. The part and the anchoring component may be coupled in the coupled arrangement via a direct anchor coupling formed of an anti-sintering agent. The method may further comprise applying the anti-sintering agent to a surface of the anchoring component to form a separation layer between the at least a portion of the at least a portion of the part and the anchoring component and decoupling the anchoring component from the part via sintering of the coupled arrangement.

[0008] Printing the part may include printing at least a portion of the part above the anchoring component and the at least a portion of the part may be the entire part.

[0009] Printing the anchoring component may include: printing the anchoring component with a component shape that extends horizontally beyond a lateral boundary of the part; printing one or more layers of the anchoring component and the part to extend the anchoring component and the part vertically upward and alongside each other; or a combination thereof.

[0010] Printing the anchoring component may include creating the anchoring component with one or more gaps of unbound powder, the one or more gaps facilitating decoupling of the anchoring component from the part.

[0011] Printing the anchoring component may include jetting the fluid into the unbound powder in a manner that defines the anchoring component as a multi-member structure.

[0012] Printing the anchoring component may include printing multiple anchoring components each having a direct or indirect anchor coupling with a respective anchoring component-facing surface of the part.

[0013] The part has a shape, and such shape may be referred to interchangeably herein as a“part” shape to distinguish its shape from that of the anchoring component. Printing the anchoring component may include printing the anchoring component with a complementary shape relative to the part shape. The complementary shape may conform to a topography of the part shape to provide for the coupled arrangement.

[0014] The method may further comprise creating a 3D computer-aided design (CAD) model of the coupled arrangement by duplicating a 3D model for the part to produce a copy of the 3D model of the part; translating the copy in a given direction to produce a translated copy; performing a 3D Boolean subtraction to subtract the 3D model of the part from the translated copy to produce a 3D model of the anchoring component; and applying an offset between the 3D model of the part and the 3D model of the anchoring component, wherein the part and the anchoring component are printed according to the 3D model of the part and the 3D model of the anchoring component, respectively.

[0015] The method may further comprise creating a 3D CAD model of the coupled arrangement by approximating surfaces of a 3D model of the part to produce an

approximated version, the approximated version being offset from the 3D model of the part in an outward direction; translating the approximated version in a given direction to produce a translated approximated version; performing a 3D Boolean subtraction to subtract the approximated version from the translated approximated version to produce a 3D model of the anchoring component, wherein the part and the anchoring component are printed according to the 3D model of the part and the 3D model of the anchoring component, respectively.

[0016] Printing the anchoring component may include jetting fluid at a first saturation level, causing powder to be bound in order to print the anchoring component. It should be understood that reference herein to powder that is“bound” (i.e., bound powder) may refer to bound powder that has been cured or that has not yet been cured. Printing the part may include jetting fluid at a second saturation level, causing powder to be bound in order to print the anchoring component. The first saturation level may be lower relative to the second saturation level. The first and second saturation levels may be saturation percentages that refer to a ratio of a volume of the fluid jetted to a total open porosity of the powder bed. For example, if the powder bed packs to 60% volume fraction, there is 40% porosity. A saturation level of 80% saturation would equate to filling 80% of the total open porosity with the fluid, or filling (0.8 * 0.4) = 32% of the total volume with fluid.

[0017] According to another example embodiment, an additive manufacturing system may comprise a spreading mechanism, printing mechanism, and controller. The controller may be configured to (i) drive the spreading mechanism to spread unbound powder to form layers of a powder bed and (ii) drive the printing mechanism to cause powder to be bound by jetting fluid, such as via at least one nozzle, into the unbound powder to print an anchoring component and a part. The controller may be further configured to drive the printing mechanism to form the anchoring component with a feature that provides a resistive force to a spreading force imposed by the spreading mechanism during the spreading and print the part in a coupled arrangement with the anchoring component. The coupled arrangement in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part.

[0018] The feature of the anchoring component may be a given number of printed layers, an inverse geometric feature that complements a geometric feature of the part, or a combination thereof.

[0019] The part and the anchoring component may be coupled in the coupled

arrangement via an indirect anchor coupling formed of unbound powder.

[0020] The controller may be further configured to drive the printing mechanism to print at least a portion of the part above the anchoring component. The part and the anchoring component may be coupled in the coupled arrangement via a direct anchor coupling. The controller may be further configured to form the direct anchor coupling by driving the spreading mechanism to spread one or more layers of the unbound powder and driving the printing mechanism to jet fluid into same in a manner that creates a multi -point connection between the at least a portion of the part and the anchoring component.

[0021] The controller may be further configured to drive the printing mechanism to print at least a portion of the part above the anchoring component. The part and the anchoring component may be coupled in the coupled arrangement via a direct anchor coupling formed of an anti-sintering agent. The system may further comprise a sintering mechanism. The controller may be further configured to drive the printing mechanism to apply the anti sintering agent to a surface of the anchoring component to form a separation layer between the at least a portion of the part and the anchoring component and drive the sintering mechanism to sinter the coupled arrangement to decouple the at least a portion of the part from the anchoring component.

[0022] The controller may be further configured to drive the printing mechanism to print at least a portion of the part above the anchoring component and the at least a portion of the part may be the entire part. [0023] The controller may be further configured to: drive the printing mechanism to print the anchoring component with a component shape that extends laterally beyond a lateral boundary of the part; print one or more layers of the anchoring component and the part that extend the anchoring component and the part vertically upward and alongside each other; or a combination thereof.

[0024] The controller may be further configured to drive the printing mechanism to create the anchoring component with one or more gaps of the unbound powder to facilitate decoupling of the anchoring component from the part. Functionally, the one or more gaps may perform at least two functions. The at least two functions may include (i) allowing access for subsequent removal of unbound powder between the anchoring component and the part and (ii) allowing the anchoring component to be split into multiple bodies to avoid“mold lock” situations in which the anchoring component and part are interlocked and difficult to separate.

[0025] The controller may be further configured to drive the printing mechanism to jet the fluid into the unbound powder in a manner that prints the anchoring component as a multi -member structure.

[0026] The controller may be further configured to drive the printing mechanism to print the anchoring component as multiple anchoring components each having a direct or indirect anchor coupling with a respective anchoring component-facing surface of the part.

[0027] The part may have a part shape and the controller may be further configured to drive the printing mechanism to print the anchoring component with a complementary shape relative to the part shape. The complementary shape may conform, at least approximately, to a topography of the part shape to provide for the coupled arrangement.

[0028] The controller may be further configured execute instructions or interpret codes that were generated according to a 3D computer-aided design (CAD) model to drive the printing mechanism to print the anchoring component and the part in the coupled

arrangement.

[0029] The controller may be further configured to drive the printing mechanism to: print the anchoring component by jetting fluid at a first saturation level; and print the part by jetting fluid at a second saturation level, wherein the first saturation level may be lower relative to the second saturation level. [0030] According to yet another example embodiment, a non-transitory computer- readable medium may have encoded thereon a sequence of instructions which, when loaded and executed by at least one processor, causes a three-dimensional (3D) printing system to drive a spreading mechanism of the 3D printing system to spread unbound powder to form layers of a powder bed and drive a printing mechanism of the 3D printing system to jet fluid into the unbound powder to print an anchoring component and a part. The sequence of instructions may further cause the 3D printing system to drive the printing mechanism to form the anchoring component with a feature that provides a resistive force to a spreading force imposed by the spreading mechanism during the spreading and print the part in a coupled arrangement with the anchoring component. The coupled arrangement in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part.

[0031] According to another example embodiment, a computer-implemented method for producing commands to drive a three-dimensional (3D) printing system may comprise producing a 3D computer-aided design (CAD) model of an anchoring component as a function of a 3D CAD model of a part. The model of the anchoring component may include a feature that provides a resistive force to a spreading force imposed by a spreading mechanism of the 3D printing system. The method may comprise producing commands as a function of the model of the part and the model of the anchoring component to produce each with fidelity to a given resolution up to the printing resolution of the 3D printing system. The commands may be a function of the part and anchoring component models as such models define the part and anchoring component that the 3D printing system is employed to print.

As such, the commands are based on the part and anchoring component models. The commands, when followed by the 3D printing system, may cause the spreading mechanism to spread unbound powder to form layers of a powder bed and may cause a printing mechanism of the 3D printing system to jet fluid into layers of the unbound powder to print the part in a coupled arrangement with the anchoring component formed with the feature. The coupled arrangement in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part.

[0032] The feature of the anchoring component may be a given number of printed layers, an inverse geometric feature that complements a geometric feature of the part, or a combination thereof.

[0033] Producing the model of the anchoring component may include duplicating the model of the part to produce a copy of the model of the part, translating the copy in a given direction to produce a translated version of the copy, performing a 3D Boolean subtraction to subtract the copy of the model of the part, or the model of the part, from the translated version of the copy to produce the 3D model of the anchoring component, and applying an offset between the 3D model of the part and the 3D model of the anchoring component. Producing the commands may take into account the offset applied.

[0034] Producing the model of the anchoring component may include approximating edges and surfaces of the model of the part to produce an approximated version of the part, the approximated version being offset from the model of the part in an outward direction, translating the approximated version in a given direction to produce a translated version of the approximated version, performing a 3D Boolean subtraction to subtract the approximated version from the translated version to produce the 3D model of the anchoring component. Producing the anchoring component may include applying an additional offset between the 3D model of the part and the 3D model of the anchoring component. Producing the commands may take into account the additional offset, if applied. It should be understood that alternative embodiments may not apply the additional offset.

[0035] According to another example embodiment, a computer-implemented method for scheduling printer instructions in a three-dimensional (3D) printing system may comprise identifying, from a plurality of 3D computer-aided design (CAD) models, at least one part of a plurality of parts as an anchoring component for at least one other part of the plurality of parts. The anchoring component may include a feature that provides a resistive force to a spreading force imposed by a spreading mechanism during spreading of unbound powder of a powder bed. The method may further comprise converting the models to printer instructions to cause printing of the anchoring component with the at least one other part in a coupled arrangement with the anchoring component. The coupled arrangement in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism.

[0036] The identifying may be performed, dynamically, as models are received by the scheduler.

[0037] The method may further comprise transmitting the printer instructions to a printer mechanism of the 3D printing system. The transmitting may cause the printer mechanism to jet binder fluid into the unbound powder to print the at least one part to serve as the anchoring component for the at least one other part in the coupled arrangement.

[0038] It should be understood that example embodiments disclosed herein can be implemented in the form of a method, apparatus, system, or computer readable medium with program codes embodied thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The foregoing will be apparent from the following more particular description of example embodiments, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments.

[0040] FIG. 1 A is a block diagram of an example embodiment of an additive

manufacturing system.

[0041] FIG. 1B is a block diagram of an example embodiment of an anchoring component and a part within a powder bed.

[0042] FIG. 1C is a block diagram of another example embodiment of an anchoring component and a part within a powder bed.

[0043] FIG. 2A is a block diagram of an example embodiment of an additive

manufacturing system.

[0044] FIG. 2B is a block diagram of an example embodiment of another additive manufacturing system.

[0045] FIG. 3 is a block diagram of an example embodiment of printing stages for printing an anchoring component and a part.

[0046] FIG. 4 is a flow diagram of an example embodiment of an additive manufacturing method. [0047] FIG. 5A is a block diagram of an example embodiment of an anchoring component.

[0048] FIG. 5B is a block diagram of the anchoring component of FIG. 5 A with a layer of unbound powder above the anchoring component.

[0049] FIG. 5C is a block diagram of the anchoring component of FIG. 5 A with multiple layers of unbound powder located between the anchoring component and the part within a powder bed.

[0050] FIG. 6A is a block diagram of another example embodiment of an anchoring component.

[0051] FIG. 6B is a block diagram of the anchoring component of FIG. 6A with a multi- member structure printed above the anchoring component.

[0052] FIG. 6C is a block diagram of a part printed in a coupled arrangement with an anchoring component.

[0053] FIG. 7A is a block diagram of an example embodiment of another anchoring component.

[0054] FIG. 7B is a block diagram of the anchoring component of FIG. 7A with an anti sintering agent (ASA) applied to a top surface of the anchoring component.

[0055] FIG. 7C is a block diagram of another example embodiment of a part printed in a coupled arrangement with an anchoring component.

[0056] FIGS. 8A-D disclose example embodiments of coupled arrangements of parts and anchoring components.

[0057] FIGS. 9A-D disclose example embodiments of various geometries for the anchoring component of the coupled arrangements disclosed in FIGS. 8A-D.

[0058] FIG. 10A is a block diagram of an example embodiment of a part and an anchoring component printed as a multi-member structure.

[0059] FIG. 10B is a block diagram of another example embodiment of a part and an anchoring component printed as a multi-member structure.

[0060] FIG. 10C is a block diagram of yet another example embodiment of a part and an anchoring component printed as a multi-member structure.

[0061] FIG. 11 A is a screen view of an example embodiment of a multi-member structure. [0062] FIG. 11B is an oblique view of an example embodiment of a part and a multi- member structure.

[0063] FIG. 11C is a cross-sectional view of an example embodiment of the part and multi -member structure of FIG. 11B.

[0064] FIG. 11D is a cross-sectional view of another example embodiment of the part and multi -member structure of FIG. 11B.

[0065] FIG. 12 is a block diagram of an example embodiment of a part in an arrangement with multiple anchoring components.

[0066] FIG. 13 A is a block diagram of an example embodiment of a part with a part shape that includes multiple downward-facing surfaces.

[0067] FIG. 13B is a block diagram of an example embodiment of a part and a copy of the part.

[0068] FIG. 13C is a block diagram of an example embodiment of a result from a 3D Boolean subtraction with an offset applied thereto.

[0069] FIG. 14A is a block diagram of another example embodiment of a part with a part shape that includes multiple downward-facing surfaces.

[0070] FIG. 14B is a block diagram of an example embodiment of an approximated version of the part of FIG. 14 A.

[0071] FIG. 14C is a block diagram of an example embodiment of a translated approximated version of the approximated version of FIG. 14B.

[0072] FIG. 14D is a block diagram of an example embodiment of another result from a 3D Boolean subtraction with an offset applied thereto.

[0073] FIG. 15A-D are block diagrams of example embodiments of coupled

arrangements of part and anchoring components.

[0074] FIG. 16A is an image of an example embodiment of a portion of a part 1610 with layer shifting.

[0075] FIG. 16B is an image of an example embodiment of the part 1610 of FIG. 16A without layer shifting and an anchoring component 1624.

[0076] FIG. 16C is an image of the example embodiment of the part 1610 of FIG. 16B without layer shifting. [0077] FIG. 17 is a block diagram of an example internal structure of a computer optionally within an embodiment disclosed herein.

DETAILED DESCRIPTION

[0078] A description of example embodiments follows.

[0079] In a binder jetting process, a thin layer of powder ( e.g ., 50 pm) is spread onto a powder bed, followed by deposition of a liquid agent in a two-dimensional (2D) pattern or image that represents a single“slice” of a three-dimensional (3D) shape. The liquid agent, also referred to interchangeably herein as a liquid, may be a liquid binder (also referred to interchangeably herein as a binder liquid). Alternatively, the powder may be coated with a binder and the liquid agent may be a liquid that activates the binder coating, such as by dissolving and redistributing the binder coating. The liquid agent may include two or more binders that cause a chemical reaction when mixed or may include binders curable by a ultraviolet (UV) light source or other energy source. The liquid agent may be any liquid applied with the intent to bind the powder on its own or as a result of a resulting reaction with another substance or activation energy source.

[0080] After deposition of the liquid, another layer of powder is spread, and the process is repeated to form the 3D shape of bound powder material inside the powder bed. It should be understood that“bound” powder may have a fluid applied to cause the powder to be bound; however, such“bound” powder may or may not have cured. Powder spreading may be accomplished by means of a dispensing apparatus that deposits a pile of powder onto the powder bed. The pile of powder may then be spread, rolled, smoothed, or compacted by means of a spreading mechanism, such as a counter-rotating roller, recoater blade, or other means for spreading. After printing and, optionally, curing based on the binder chemistry, the bound part is removed from the excess unbound powder, and, optionally, sintered at high temperature to bind the particles together. Sintering may be performed to densify the part to full density (i.e., removal of all void space) or may be performed to bond the particles only lightly without substantial removal of void space. Sintering may be optional as the part may be used in a printed-and-cured state. Further, the part may be infiltrated with another material, such as a different metal, polymer, etc. [0081] During the process of spreading a new layer of powder onto the powder bed, the spreading mechanism can apply a spreading force, also referred to interchangeably herein as a shearing force, that can cause defects in one or more previously printed layers. These defects can include:“shifting” (z.e., translation of layers in the powder bed); and“cracking” (z.e., breakup of the layers). Shifting may include translating printed layers of powder without substantial introduction of voids within the layers. Breaking up a layer may include one or more horizontal discontinuities within the layer or one or more voids within the layer. Shifting or breaking up the layers may refer to causing printed layers to shift with a vertical component to their motion, which may, in turn, cause some aspect of the layers to project above a previously defined top surface of the layer. Such defects may be referred to collectively herein as“smearing,”“shifting,” or“cracking,” but all generally refer to the “smeared” or“shifted” layers of a printed part. An example embodiment disclosed herein prevents such layer“shifting,”“smearing,” and“cracking” of layers of printed parts by means of immobilizing the layers during printing by printing an anchoring component, also referred to interchangeably herein as a“raft,” under one or more portions of the part being printed. As such, a method may reduce layer shifting and smearing during 3D printing by means of printed raft(s). Such printed raft(s) may be disposed of and, as such, may be referred to as sacrificial raft(s). Alternatively, such raft(s) may be parts themselves that advantageously immobilize, at least partially, at least one printed layer of another part in the powder bed such that the at least one printed layer of the other part resists the spreading force imposed by the spreading mechanism.

[0082] FIG. 1 A is a block diagram of an example embodiment of an additive

manufacturing system 150. The additive manufacturing system 150 comprises a modeler 153, scheduler 130 (also referred to interchangeably herein as a controller), and 3D printer 151. The modeler 153 is configured to generate a 3D computer-aided design (CAD) model 134 based on a description 155 of a 3D part 110 that is to be printed by the 3D printer 151. The description 155 may be any suitable description that describes geometry and other features of the 3D part 110 such that a 3D CAD model can be produced that represents the 3D part 110.

[0083] The scheduler 130 may be configured to convert the 3D CAD model 134 into printer instructions 157 that are configured to cause the 3D printer 151 to produce the 3D part 110. In order to produce the 3D part 110 from the 3D printer 151 with a higher quality, the 3D CAD model 134 may include a model of an anchoring component (not shown) for printing in a coupled arrangement with the 3D part 110 to prevent smearing and other defects that are induced via spreading forces of a spreading mechanism 15 of the 3D printer 151, as disclosed above and further below. The anchoring component may be a sacrificial anchoring component (also referred to interchangeably herein as a“sacrificial component” for simplicity) that may be disposed of following printing of the 3D part 110. Alternatively, the anchoring component may be another part of the plurality of 3D parts 111 that are produced by the 3D printer for any suitable use.

[0084] According to an example embodiment, the scheduler 130 may be configured to determine a spatial arrangement of the plurality of 3D parts 111 to be printed in a powder bed 20 based on the plurality of 3D CAD models 159. The spatial arrangement may be determined such that usage of powder is increased. For example, the spatial arrangement may be determined to reduce an amount of unbound powder between the plurality of 3D parts 111 in the powder bed 20. Further, the spatial arrangement may be determined such that at least one 3D part 110 of the plurality of parts 111 serves as an anchoring component for at least one other 3D part 110 to minimize a number of sacrificial components.

[0085] The scheduler 130 may be configured to generate the printer instructions 157 to print the plurality of 3D parts 111. Generating the printer 157 instructions may include creating such instructions or modifying pre-existing instructions. The scheduler 130 may generate the printer instructions 157 that drive a dispensing apparatus (not shown) to release unbound powder, drive the spreading mechanism 15 to spread the unbound powder to form layers of the powder bed 20, and drive the printing mechanism 19 to jet fluid (not shown) into the unbound powder according to a controlled pattern to cause regions of the unbound powder to bind.

[0086] According to an example embodiment, the scheduler 130 may be configured to perform a computer-implemented method for scheduling printer instructions in a 3D printing system. The method may comprise identifying, from a plurality of 3D computer-aided design (CAD) models, at least one part of a plurality of parts as an anchoring component for at least one other part of the plurality of parts. The anchoring component may include a feature that provides a resistive force to a spreading force imposed by a spreading mechanism during spreading of unbound powder of a powder bed. The method may further comprise converting the models to printer instructions to cause printing of the anchoring component with the at least one other part in a coupled arrangement with the anchoring component. The coupled arrangement in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism. The identifying may be performed, dynamically, as models are received.

[0087] The method may further comprise transmitting the printer instructions to a printer mechanism of the 3D printing system. The transmitting may cause the printer mechanism to jet fluid into the unbound powder to print the at least one part to serve as the anchoring component for the at least one other part in the coupled arrangement.

[0088] It should be understood that the modeler 153 and scheduler 130 may be co-located with the 3D printer 151 or at a remote location relative to the 3D printer 151. The modeler 153 may be configured to store the 3D CAD model 134 in a database, such as the computer readable storage medium 232 of FIG. 2A, disclosed further below, for access by the scheduler 130. Alternatively, the modeler 153 may be communicatively coupled to the scheduler via any suitable electronic communication link and may be configured to transmit the 3D CAD model directly to the scheduler 130. The modeler 153 and scheduler 130 may be implemented by one or more processors. The modeler 153 and scheduler 130 may be implemented by the same one or more processors or by different processors. Such one or more processors may be configured to perform operations of the modeler 153 and scheduler 130 disclosed herein by loading and executing a sequence of instructions.

[0089] As disclosed above and further below, an anchoring component may at least partially immobilize at least one layer of a part in the powder bed 20 to resist a spreading force. Such immobilizing may not affect a“perfect” part, that is, a part with substantially no defects; however, such immobilization prevents at least one defect in the part from being imparted into it by the printing process. In other words, the at least one defect might otherwise be present in the part had the part not been printed in the coupled arrangement with the anchoring component. In some cases, additional post-processing of the part, such as polishing or any other suitable post-processing that improves quality of the part may be performed to remove any minor imperfections caused by the spreading force despite the use of the anchoring component 24.

[0090] FIG. 1B is a block diagram of an example embodiment of an anchoring component 24 and a part 10 within a powder bed 20. The anchoring component 24 is printed using a three-dimensional (3D) printing system (not shown), such as the 3D printing system 250 of FIG. 2A, disclosed further below, or any other suitable 3D printing system that includes (i) a spreading mechanism 15 for spreading unbound powder 4 to form layers of a powder bed 20, such as the layer 35 of the powder bed 20, and (ii) a printing mechanism 19 for jetting fluid 22 into the unbound powder 4 to form the anchoring component 24. Jetting the fluid 22 into the unbound powder 4 produces the bound powder 33. Regions of the bound powder 33 may be referred to as“printed” regions. The anchoring component 24 is formed with a feature (not shown) that provides a resistive force (not shown) to a spreading force 12 imposed by the spreading mechanism 15 during the spreading. The resistive force may be represented as one or more vector arrows (not shown) that are equal and opposite to vector arrows of the spreading force 12.

[0091] The spreading force 12 may be any force(s) induced by the spreading mechanism as the spreading mechanism spreads the unbound powder 4. The spreading force 12 may include forces that are lateral, that is, in the plane of the layer, vertical, that is, out of the plane of the layer, or a combination thereof. Spreading may include rolling, compacting, or any other suitable action that causes a deposited volume of the unbound powder 4 to be extended, spread, or smoothed on the powder bed 20. The part 10 is printed with the 3D printing system in a coupled arrangement 26 with the anchoring component 24. The coupled arrangement 26 in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part 10 in the powder bed 20 to resist the spreading force 12 imposed by the spreading mechanism 15 during spreading of the unbound powder 4 above the at least one printed layer of the part 10. According to an example embodiment, the at least one printed layer may be each printed layer.

[0092] According to an example embodiment, at least a portion of the unbound powder 4 provides the resistive force. The part 10 and the anchoring component 24 may be coupled in the coupled arrangement 26 via an anchor coupling 5. The anchor coupling 5 may be a direct or indirect anchor coupling. For example, the anchor coupling 5 may be a direct anchor coupling formed by at least a portion of the part 10 being bound directly to the anchoring component 24 or by at least of portion of the part 10 and the anchoring component 24 each being bound to a printed structure interposed therebetween, such as the multi-member structure 1121 of FIG. 11 A, disclosed below, or any other suitable printed structure that is a non-contiguous structure with multiple members. The multi-member structure may be any suitable printed structure that has multiple contact points with the part and multiple contact points with the anchoring component. Such a printed structure may include multiple printed members that form a pattern that is regular in some embodiments, and random or pseudo- random in other embodiments. According to an example embodiment, the multiple printed members may form columns that extend vertically between the part and anchoring component. According to an example embodiment, the multiple printed members may form a grid, mesh, or interlaced pattern, such as the lattice structure of FIG. 11 A that includes multiple members that are crossed and connected.

[0093] It should be understood that being“bound” directly may include connections that have not yet cured. The part 10 and the anchoring component may be printed as a single printed part in the coupled arrangement 26. According to an example embodiment, the part 10 and the anchoring component 24 may be printed in a coupled arrangement 26 with an anchor coupling 5 that is an indirect anchor coupling, for example, the indirect anchor coupling may be formed of unbound powder 4.

[0094] The feature of the anchoring component 24 may be a given number of printed layers, an inverse geometric feature that complements a geometric feature of the part, or a combination thereof. Example embodiments of the feature are disclosed, further below.

[0095] FIG. 1C is a block diagram of another example embodiment of an anchoring component 124 and a part 110 within a powder bed 120. The anchoring component 124 and the part 110 may be printed by a 3D printing system (not shown) in a coupled arrangement, as disclosed above. In the example embodiment of FIG. 1C, at least a portion of the part 110 is printed above the anchoring component 124 and is coupled to the anchoring component 124 via a direct anchor coupling 105 as the printed layer l08a of the part is bound to at least a portion of the printed layer l02e of the anchoring component 124. In the example embodiment of FIG. 1C, the anchoring component 124 is formed with a feature that provides a resistive force (not shown) to a spreading force 112 imposed by spreading of the unbound powder 104 by the spreading mechanism 115. In the example embodiment, the feature of the anchoring component 124 includes a given number of printed layers, that is, five, in the example embodiment, namely, the printed layers l02a-e that are located below the anchor coupling 105.

[0096] The anchoring component 124 and the part 110 reside within a powder bed 120. Printing of the anchoring component 124 and the part 110 includes jetting fluid (not shown) into layers of the unbound powder 104 of the powder bed 120 spread by the spreading mechanism 115 on a layer-by-layer basis, such as disclosed below with reference to FIG. 2A.

[0097] In the example embodiment of FIG. 1C, printing of the anchoring component 124 includes jetting fluid into the powder layers l06b, l06c, l06d, l06e, and l06f, while printing of the part 110 includes jetting fluid into the powder layers l06g, l06h, and l06i, of the plurality of powder layers l06a-j that are spread by the spreading mechanism 115, yielding the printed layers l02a-e of the anchoring component and the printed layers l08a-c of the part 110.

[0098] According to the example embodiment, the coupled arrangement of the part 110 and the anchoring component 124 in combination with the resistive force of the feature, that is, the given number of layers of the anchoring component 124, is sufficient to at least partially immobilize at least one printed layer of the part 110, that is, the printed layers l08a- c, to resist the spreading force 112 imposed by the spreading mechanism 115 during spreading of the unbound powder 104 at powder layers l06h, l06i, and l06j, each above a printed layer of the part 110. It should be understood that the powder layers l06b-f include the printed layers l02a-e and that the printed layers l02a-e reflect portions of their respective powder layers l06b-f that have fluid applied thereto. Further, the powder layers 106g— i include the printed layers l08a-c and the printed layers l08a-c reflect portions of their respective powder layers 106g— i that have fluid applied thereto. The spreading force 112 is imposed by physical interaction of the spreading mechanism 115 with the powder layers 106b— j . After printing, and before or after post-processing (such as de-binding or sintering), the part 110 is separated from the anchoring component 124. Following decoupling from the part 110, the anchoring component 124 may be disposed of, having served to ensure quality of the part 110 ( e.g ., preventing smearing of the part 110) during the printing process. Such an anchoring component may be referred to as a sacrificial component. Alternatively, the anchoring component 124 may not be sacrificial and may be another part that is not disposed of, for example, after sintering.

[0099] As illustrated in FIG. 1C, the printed layers l02a-e of the anchoring component 124 experience shifting, relative to a respective original printed location 107, due to the spreading force 112. Because the anchoring component 124 incurs effects of the spreading force 112 and because the part 110 is printed in a coupled arrangement with the anchoring component 124, the printed layers l08a-c of the part 110 at least partially resist the spreading force 112 and, thus, do not experience shifting. In the example embodiment, the given number of layers of the anchoring component 124 is five; however, the given number may be any suitable number that enables printed layer(s) of the part 110 to resist the spreading force 112 caused by the spreading mechanism 115. Further, it should be understood that the part 110 may have any suitable shape or number of printed layers to form a target 3D part. In addition, while FIG. 1C discloses spreading of the powder layer l06j, it should be understood that such spreading is shown for illustrative purposes to show the spreading force 112 and that a powder layer may not be spread over the part 110 following printing of the part 110.

[00100] FIG. 2A is a block diagram of an example embodiment of another additive manufacturing system 250. The additive manufacturing system 250 comprises a spreading mechanism 215, printing mechanism 219, and controller 230. The controller 230 is configured to (i) drive the spreading mechanism 215 to spread unbound powder 204 to form layers of a powder bed 220 and (ii) drive the printing mechanism 219 to jet fluid 222 into the unbound powder 204 to print an anchoring component 224 and a part 210. The controller 230 is further configured to drive the printing mechanism 219 to form the anchoring component 224 with a feature that provides a resistive force to a spreading force 212 imposed by the spreading mechanism 215 during the spreading and print the part 210 in a coupled arrangement 226 with the anchoring component 224. The coupled arrangement 226 in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part 210 in the powder bed 220 to resist the spreading force 212 imposed by the spreading mechanism 215 during spreading of the unbound powder 204 above the at least one printed layer of the part 210.

[00101] The feature of the anchoring component 224 may be a given number of printed layers, an inverse geometric feature that complements a geometric feature of the part 210, or a combination thereof. It should be appreciated that any one or more methods described with respect to the formation of a given layer of the part 210 or anchoring component 224 may be repeated as necessary to form a respective plurality of layers making up the part 210 or anchoring component 224. The anchoring component 224 and the part 210 are three- dimensional (3D) objects. The unbound powder 204 may include, without limitation, metallic particles, ceramic particles, polymeric particles, and combinations thereof. The additive manufacturing system may further comprise a sintering mechanism (not shown).

The part 210, anchoring component 224, or a combination thereof, may be subsequently processed ( e.g ., sintered) by the sintering mechanism (not shown) to form a finished part that is separate from the anchoring component 224. In addition to or instead of sintering, other processing of the part 210 may be performed to form the finished part.

[00102] The additive manufacturing system 250 may further comprise a powder supply 217, print box 214, and at least one nozzle 218. The print box 214 includes a build platform 213, such as a piston, that is moveable within the print box 214. The print box 214 may have any suitable shape and includes walls which, in combination with a top surface of the build platform 213, contains the powder bed 220 which is formed by spreading layers of the unbound powder 204 above the build platform 213. The powder supply 217 is a dispensing apparatus that deposits a pile of the unbound powder 204 onto the powder bed 220.

According to the example embodiment, the dispensing apparatus is a hopper with an opening from which the unbound powder 204 flows to deposit the pile of unbound powder 204. The pile of unbound powder 204 may then be spread, rolled, smoothed, or compacted by means of the spreading mechanism 215, such as a counter-rotating roller, recoater blade, or other means for spreading.

[00103] The build platform 213 is configured to move downward within the print box 214 following spreading of a layer of the unbound powder 204 and, optionally, jetting the fluid 222 into same. The spreading mechanism 215 is moveable along the print box 214 to spread successive layers of the unbound powder 204 across the powder bed 220. The powder bed 220 may have a maximum number of layers defined by the print box 214 and layer thickness.

[00104] The at least one nozzle 218 and the printing mechanism 219 may be movable (e.g., in coordination with one another and, optionally, in coordination with movement of the spreading mechanism 215) across the powder bed 220 to form a plurality of layers and, ultimately, to form the anchoring component 224 and the part 210. The spreading mechanism 215, at least one nozzle 218, and printing mechanism 219 may be movable over the print box 214. It should be understood that any manner and form of relative movement of components of the additive manufacturing system 250 may be used to carry out any one or more of the binder jetting processes described herein. Thus, for example, the print box 214 may be, further or instead, movable with respect to one or more of the spreading mechanism 215, at least one nozzle 218, and printing mechanism 219 to achieve relative movement of components, as necessary to carry out any one or more of the binder jetting processes described herein.

[00105] The spreading mechanism 215 may generally span at least one dimension of the powder bed 220 such that the spreading mechanism 215 may distribute a layer of the unbound powder 204 on top of the powder bed 220 in a single pass. As an example, the spreading mechanism 215 may include a roller rotatable about an axis perpendicular to an axis of movement of the spreading mechanism 215 across the print box 214.

[00106] The roller may be, for example, substantially cylindrical. In use, rotation of the roller about the axis perpendicular to the axis of movement of the spreading mechanism 215 may spread the unbound powder 204 that flows from the powder supply 217 to the print box

214 to form a layer of the unbound powder 204 of the powder bed 220. It should be appreciated, therefore, that the plurality of sequential layers of the unbound powder 204 of the powder bed 220 may be formed through repeated movement of the spreading mechanism

215 across the powder bed 220. The thickness of each layer of the unbound powder 204 may be substantially uniform and, in particular, may be about 65 microns. Other dimensions are additionally or alternatively possible. For example, layer thickness may be between 30 and 100 microns depending on many factors, such as particle size, binder, desired surface finish, etc.

[00107] The printing mechanism 219 may direct fluid into the powder bed 220 as the printing mechanism 219 moves across the powder bed 220. While the printing mechanism 219 may be illustrated as a single printhead, it should be appreciated that the printing mechanism 219 may, additionally or alternatively, include a plurality of printheads from which the fluid 222 may be jetted into the powder bed 220. Further, it should be understood that jetting of the fluid 222 into the unbound powder 204 of the powder bed may be jetted from any direction, such as at any angle relative to a plane of the layer of powder.

[00108] The controller 230 may be in electrical communication with the powder supply

217, build platform 213, print box 214, spreading mechanism 215, printing mechanism 219, and at least one nozzle 218 to drive functionality of same. The controller 230 may include one or more processors 231 operable to control the powder supply 217, build platform 213, print box 214, spreading mechanism 215, printing mechanism 219, and at least one nozzle

218, and combinations thereof.

[00109] The one or more processors 231 of the controller 230 may execute instructions to control movement of one or more of the powder supply 217, build platform 213, print box 214, spreading mechanism 215, printing mechanism 219, and at least one nozzle 218 relative to one another as the anchoring component 224 and the part 210 are being formed. For example, the one or more processors 231 of the controller 230 may execute instructions to move the powder supply 217 to direct the unbound powder 204 toward powder bed 220, move the spreading mechanism 215 to spread the unbound powder 204 across the powder bed, move the printing mechanism 219 to jet fluid into a layer of unbound powder of the powder bed, and to move the build platform 213 in a z-axis direction away from the spreading mechanism 215 to accept each new layer of the powder 204 along the top of the powder bed 220 as the spreading mechanism 215 moves across the powder bed 220. In general, the controlled movement of the build platform 213 is based on a thickness of a corresponding layer being formed in the powder bed 220.

[00110] Additionally, or alternatively, the one or more processors 231 of the controller 230 may execute instructions to control movement of the spreading mechanism 215 to spread successive layers of the unbound powder 204 across the powder bed 220. For example, the one or more processors 231 of the controller 230 may control speed of movement of the spreading mechanism 215 across the powder bed 220. As a further or alternative example, the controller 230 may control one or more features of the spreading mechanism 215 useful for packing the top layer of the powder bed 220 as the spreading mechanism 215 moves across the powder bed 220. Returning to the specific example of the spreading mechanism 215 being rotatable, the one or more processors 231 of the controller 230 may control rotation ( e.g ., speed, direction, or both) of the spreading mechanism 215. [00111] The one or more processors 231 of the controller 230 may, further or instead, control the printing mechanism 219. For example, the one or more processors 231 of the controller 230 may control movement ( e.g ., speed, direction, timing, and combinations thereof) of the printing mechanism 219 across the powder bed 220 as well as jetting of the fluid 222 from the printing mechanism 219 into unbound powder of the powder bed 220.

The one or more processors 231 may control the printing mechanism 219 to jet the fluid 222 into unbound powder of the powder bed 220 along a controlled two-dimensional pattern associated with a given layer. The controlled two-dimensional pattern may vary from layer- to-layer, as necessary, according to a component shape of anchoring component 224 and a part shape of the part 210 being formed in the powder bed 220.

[00112] The additive manufacturing system 250 may further, or instead, include a non- transitory, computer readable storage medium 232 in communication with the controller 230 and having stored thereon a three-dimensional model(s) 234 and instructions for causing the one or more processors 231 to carry out any one or more of the methods described herein. In general, as a plurality of sequential layers of the powder unbound powder 204 are introduced to the powder bed 220, the anchoring component 224 and the part 210 are formed according to the three-dimensional model(s) 234 stored in the non-transitory, computer readable storage medium 232. In certain implementations, the controller 230 may retrieve the three- dimensional model(s) 234 in response to user input, and generate machine-ready instructions for execution by the additive manufacturing system 250 to fabricate the anchoring component 224 and the part 210.

[00113] In the example embodiment of FIG. 2A, at least a portion of the part 210 is printed above the anchoring component 224 and is coupled to the anchoring component 224 via an anchor coupling 205 that may be an indirect or direct anchor coupling, as disclosed herein. The controller 230 may be further configured to drive the printing mechanism 219 to print the at least a portion of the part above the anchoring component 224.

[00114] According to an embodiment, the part 210 and the anchoring component 224 may be coupled in the coupled arrangement 226 via an indirect anchor coupling formed of the unbound powder 204. According to another embodiment, the part 210 and the anchoring component 224 may be coupled in the coupled arrangement 226 via a direct anchor coupling. For example, the controller 230 may be further configured to form the direct anchor coupling by driving the spreading mechanism 215 to spread one or more layers of the unbound powder 204 and driving the printing mechanism 219 to jet the fluid 222 into same in a manner that creates a multi -member structure, such as the multi-member structure 1121 of FIG. 11 A, disclosed further below, that may be created between the at least a portion of the part and the anchoring component.

[00115] The controller 230 may be further configured to drive the printing mechanism 219 to print at least a portion of the part 210 above the anchoring component. The part 210 and the anchoring component 224 may be coupled in the coupled arrangement via a direct anchor coupling formed of an anti-sintering agent (ASA), as disclosed further below with reference to FIG. 7B. The controller 230 may be further configured to drive the printing mechanism 219 to apply the ASA to a surface of the anchoring component 224 to form a separation layer between the at least a portion of the part 210 and the anchoring component 224 and drive the sintering mechanism (not shown) to sinter the coupled arrangement 226 to decouple the at least a portion of the part 210 from the anchoring component 224.

[00116] According to an example embodiment, the controller 230 may be further configured to drive the printing mechanism 219 to print at least a portion of the part 210 above the anchoring component 224 and the at least a portion of the part 210 may be the entire part.

[00117] According to an example embodiment, the controller 230 may be further configured to: drive the printing mechanism 219 to print the anchoring component 224 with a component shape that extends laterally beyond a lateral boundary of the part 210; print one or more layers of the anchoring component 224 and the part 210 that extend the anchoring component 224 and the part 210 vertically upward and alongside each other; or a

combination thereof, such as disclosed below with reference to FIG. 8B and FIG. 8C.

[00118] According to an example embodiment, the controller 230 may be further configured to drive the printing mechanism 219 to create the anchoring component 224 with one or more gaps of the unbound powder 204 to facilitate decoupling of the anchoring component 224 from the part 210, such as disclosed further below with reference to FIG. 8D.

[00119] According to an example embodiment, the controller 230 may be further configured to drive the printing mechanism 219 to jet the fluid 222 into the unbound powder 204 in a manner that prints the anchoring component 224 as a multi-member structure, such as the multi-member structure 1121, disclosed further below with reference to FIG. 11 A.

[00120] According to an example embodiment, the controller 230 may be further configured to drive the printing mechanism 219 to print the anchoring component 224 as multiple anchoring components each having a direct or indirect anchor coupling with a respective anchoring component-facing surface of the part, such as disclosed below with reference to FIG. 12.

[00121] According to an example embodiment, the part 210 may have a shape, referred to interchangeably herein as a“part” shape, and the controller 230 may be further configured to drive the printing mechanism 219 to print the anchoring component 224 with a

complementary shape relative to the part shape. The complementary shape may conform to a topography of the part shape to provide for the coupled arrangement. The complementary shape may be a less complex shape relative to the part sharp, wherein the less complex shape approximates the part shape. For example, the less complex shape may not exactly conform to the topography of the part shape, thus reducing complexity of the complementary shape. The less complex shape may have a complementary shape that conforms to the topography of the part shape; however, the less complex shape may be geometrically less complex with fewer turns and angles and, in some embodiments, may be smoother relative to the topography of the part shape. The less complex shape may be a given shape that has a larger volume and/or lower surface area relative to the part’s volume and surface area.

[00122] According to an example embodiment, the controller 230 may be further configured execute instructions or interpret codes that were generated according to the 3D CAD model(s) 234 to drive the printing mechanism 219 to print the anchoring component 224 and the part 210 in the coupled arrangement 226.

[00123] According to an example embodiment, the controller 230 may be further configured to drive the printing mechanism 219 to: print the anchoring component 224 by jetting the fluid 222 at a first saturation level; and print the part 210 by jetting the fluid 222 at a second saturation level, wherein the first saturation level may be lower relative to the second saturation level, such as disclosed further below with reference to FIGS. 15A-D. The first and second saturation levels may be saturation percentages that refer to a ratio of a volume of the fluid jetted to a total open porosity of the powder bed. For example, if the powder bed packs to 60% volume fraction, there is 40% porosity. A saturation level of 80% saturation would equate to filling 80% of the total open porosity, or (0.8 * 0.4) = 32% of the total volume with fluid.

[00124] FIG. 2B is a block diagram of another example embodiment of an additive manufacturing system 2250. The example embodiment of the additive manufacturing system 2250 includes an alternative embodiment of the powder supply 217 relative to the example embodiment of the additive manufacturing system 250 of FIG. 2A, disclosed above.

[00125] According to the example embodiment, the print box 214 includes the powder supply 217 for depositing the pile of unbound powder 204. As in the example embodiment of FIG. 2A, disclosed above, the pile of unbound powder 204 may then be spread, rolled, smoothed, or compacted by means of the spreading mechanism 215, such as a counter rotating roller, recoater blade, or other means for spreading.

[00126] According to the example embodiment of FIG. 2B, the spreading mechanism 215 may be movable from the powder supply 217 to the powder bed 220 and along the powder bed 220 to spread successive layers of the unbound powder 204 across the powder bed 220. As in the example embodiment of FIG. 2A, disclosed above, the at least one nozzle 218 and the printing mechanism 219 may be movable (e.g., in coordination with one another and, optionally, in coordination with movement of the spreading mechanism 215) across the powder bed 220 to form a plurality of layers and, ultimately, to form the anchoring component 224 and the part 210.

[00127] According to the example embodiment of FIG. 2B, the one or more processors 231 of the controller 230 may execute instructions to control z-axis movement of one or more of the powder supply 217 and the build platform 213 relative to one another as the anchoring component 224 and the part 210 are being formed. For example, the one or more processors 231 of the controller 230 may execute instructions to move the powder supply 217 in a z-axis direction toward the spreading mechanism 215 to direct the unbound powder 204 toward the spreading mechanism 215 as each layer is formed and to move the build platform 213 in a z- axis direction away from the spreading mechanism 215 to accept each new layer of the unbound powder 204 along the top of the powder bed 220 as the spreading mechanism 215 moves across the powder bed 220. Movement of the powder supply 217 may be performed by driving movement of a powder supply platform 229. The powder supply platform may be any suitable moveable platform, such as a piston.

[00128] In general, the controlled movement of the build platform 213 relative to the powder supply 217 is based on a thickness of a corresponding layer being formed in the powder bed 220. Movement of the powder supply 217 may be upward via a powder supply platform. Additionally, or alternatively, the one or more processors 231 of the controller 230 may execute instructions to control movement of the spreading mechanism 215 from the powder supply 217 to the powder bed 220 to spread successive layers of the unbound powder 204 across the powder bed 220.

[00129] FIG. 3 is a block diagram of an example embodiment of printing stages for printing an anchoring component 324 and a part 310 in a coupled arrangement. In a first printing stage 321, a first printed layer 302a of the anchoring component 324 is printed by jetting fluid into unbound powder of the powder bed layer 306b spread on top of the unbound powder of the powder bed layer 306a of a powder bed 320.

[00130] In a second printing stage 323, a next layer of unbound powder is spread across a current top surface of the powder bed 320, where the current top surface in the second printing stage 323 is the powder bed layer 306b that includes the printed layer 302a of the anchoring component 324 and unbound powder. A spreading mechanism 315, such as a roller or any other suitable spreading mechanism, is used to spread the unbound powder of the powder bed layer 306c across the current top surface of the powder bed 320 and applies a spreading force 3 l2a during the spreading. In response to the spreading force 3 l2a, the printed layer 302a shifts 303 relative to its original printed location 307a. As such, the spreading force 3 l2a from the spreading mechanism 315 causes the previously printed layer, that is, the printed layer 302a of the anchoring component 324, to shift relative to its original printed location 307a.

[00131] In a third printing stage 325, fluid is jetted into unbound powder of the powder bed layer 306c to form a next printed layer of the anchoring component 324, that is, the printed layer 302b. The powder bed layer 306c includes the printed layer 302b of the anchoring component 324 and unbound powder and becomes the current top surface layer of the powder bed 320. [00132] In a fourth printing stage 327, additional layers of the anchoring component 324 are printed, namely the printed layers 302c, 302d, and 302e, by spreading unbound powder to successively form the powder bed layers 306d, 306e, and 306f and jetting fluid into same. Following the printing of a given number of layers of the anchoring component 324, that is, five in the example embodiment, a feature of the anchoring component 324 has been formed that provides a resistive force to the spreading force imposed by the spreading mechanism 315 during spreading. Additional layers of unbound powder are spread to form additional powder bed layers of the powder bed 320, namely, the powder bed layers 306g, 306h, and 306i, and fluid is jetted into same to print the printed layers 308a, 308b, and 308c of the part 310.

[00133] As disclosed in FIG. 3, there is less shifting of the printed layers 308a, 308b, and 308c of the part 310, relative to an original printed location 307b, as compared to shifting of the printed layers 302a e of the anchoring component 324, relative to the original printed location 307b. Any shifting of the printed layers 308a, 308b, and 308c of the part 310 may be referred to as "substantially less shifting" that may mean that there is no shifting of regions of the printed layers 308a, 308b, and 308c of the part 310 by more than 1 mm from their originally printed location, more preferably by no more than 100 pm, and most preferably by no more than 20 pm. According to an example embodiment there may be no shifting of regions of printed layers of the part by more than a native resolution of a printhead of the printing mechanism. According to an example embodiment, the native resolution of the printhead may be approximately 20 pm; however, it should be understood that the native resolution may be any suitable native resolution.

[00134] Such shifting is caused by the spreading force 3 l2b imposed by the spreading mechanism 315 during spreading of unbound powder above such layers. Shifting due to the spreading force 3 l2b is limited, substantially, to the five printed layers of the anchoring component 324. The five printed layers of the anchoring component 324 serve as an anchor for printed layers of the part 310 and form a feature of the anchoring component 324 that provides a resistive force to the spreading force imposed by the spreading mechanism during spreading of unbound powder. As disclosed in the example embodiment of FIG. 3, at least a portion of the part 310 is above the anchoring component 324 in the coupled arrangement. In the example embodiment, the anchor coupling 305 between the part 310 and the anchoring component 324 is a direct anchor coupling.

[00135] The five printed layers 306b-f of the anchoring component 324 are lower in the powder bed relative to the printed layers 308a-c. The coupled arrangement of the part 310 and the anchoring component 324 in combination with the resistive force provided by at least the given number of layers, that is, the five printed layers 306b-f of the anchoring component 324, is sufficient to at least partially immobilize at least one printed layer of the part 310 in the powder bed 320, that is, the printed layers 308a-c, to resist the spreading force 3 l2b imposed by the spreading mechanism 315 during spreading of unbound powder above the at least one printed layer of the part 310.

[00136] FIG. 4 is a flow diagram 401 of an example embodiment of an additive manufacturing method. The method begins (402) and prints an anchoring component using a three-dimensional (3D) printing system including (i) a spreading mechanism for spreading unbound powder to form layers of a powder bed and (ii) a printing mechanism for jetting fluid into the unbound powder to form the anchoring component with a feature that provides a resistive force to a spreading force imposed by the spreading mechanism during the spreading (404). The method prints a part with the 3D printing system in a coupled arrangement with the anchoring component, the coupled arrangement in combination with the resistive force being sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part (406), and the method thereafter ends (408) in the example embodiment. According to an example embodiment, the at least one printed layer may be each printed layer.

[00137] FIG. 5A is a block diagram of an example embodiment of an anchoring component 524. In the example embodiment, shifting is present in lower layers of the anchoring component 524 referred to interchangeably herein as a raft.

[00138] FIG. 5B is a block diagram of the anchoring component 524 of FIG. 5 A with a layer 505a of unbound powder spread above the anchoring component 524. The layer 505a of unbound powder may serve as an indirect anchor coupling between the anchoring component 524 and a printed layer of the part (not shown) that is printed above the layer 505a of unbound powder. [00139] FIG. 5C is a block diagram of the anchoring component 524 of FIG. 5 A with multiple layers of unbound powder 505b located between the anchoring component 524 and the part 510 within a powder bed 520. The multiple layers of unbound powder 505b may serve as an indirect anchor coupling between the anchoring component 524 and the part 510. The part 510 is printed in a coupled arrangement with the anchoring component 524 and, in the coupled arrangement, the anchoring component 524 (z.e.,“raft”) is printed underneath the part 510, and any smearing or layer shifting occurs on the anchoring component 524. After the raft is at least some number of layers in thickness (at least one layer, preferably at least 10 layers, most preferably at least 30 layers), the raft has been formed with a feature that provides a resistive force to a spreading force imposed by a spreading mechanism (not shown) during spreading. Subsequently, in the example embodiment, at least one layer of powder, such as the layers 505a or 505b, may be spread without fluid (preferably between one layer and 20 layers, more preferably between 2 and 10 layers, most preferably between 3- 5 layers of powder), followed by printing of the part 510.

[00140] FIG. 6A is a block diagram of another example embodiment of an anchoring component 624. In the example embodiment, shifting is present in lower layers of the anchoring component referred to interchangeably herein as a raft.

[00141] FIG. 6B is a block diagram of the anchoring component 624 of FIG. 6A with a multi-member structure 605 printed above the anchoring component 624. The multi-member structure 605 may serve as a direct anchor coupling between the anchoring component 624 and a printed layer of the part (not shown) that is printed above the multi-member structure 605. For example, the multi-member structure 605 includes a first member 607a, second member 607b, and third member 607c. The multi-member structure 605 has multiple contact points with the anchoring component 624 as well as the part, as shown in FIG. 6C, disclosed below.

[00142] FIG. 6C is a block diagram of a part 610 printed in a coupled arrangement with an anchoring component 624. The anchoring component 624 is formed with a feature that provides a resistive force to a spreading force imposed by a spreading mechanism (not shown). After the raft, that is, the anchoring component 624, is at least some number of layers in thickness (at least one layer, preferably at least 10 layers, most preferably at least 30 layers), the feature is formed, and an anchor coupling, that is, the multi-member structure 605, is printed between the raft and the bottom of the part, in the example embodiment. The multi-member structure 605 is a non-contiguous body minimizing or reducing powder and fluid use. The printed part 610 is coupled, directly, to the anchoring component 624 by the anchor coupling, that is, the multi-member structure 605 that is printed above the anchoring component 624 in the coupled arrangement. The coupled arrangement in combination with the resistive force, locks the printed part 610 in place in the powder bed 620 and the part 610 experiences reduced or limited shifting and any smearing or layer shifting occurs, primarily, on the anchoring component 624. Design of the multi-member structure and anchoring component 624 may enable (i) reduced or limited shifting/smearing of the part while (ii) minimizing or reducing powder and binder use, and (iii) limiting the impact on the part surface of having additional printed features.

[00143] FIG. 7A is a block diagram of an example embodiment of another anchoring component 724. In the example embodiment, shifting is present in lower layers of the anchoring component 724 referred to interchangeably herein as a raft.

[00144] FIG. 7B is a block diagram of the anchoring component 724 of FIG. 7A with an anti-sintering agent (ASA) applied to the top surface 705 of the anchoring component 724 to form a sinter-resistant layer. The top surface 705 of the anchoring component 724 may serve as a direct anchor coupling between the anchoring component 724 and a printed layer of the part (not shown) that is printed above the top surface 705 having the ASA applied. The ASA may include a material that does not sinter or densify during the typical sintering process for the part. The ASA may be miscible with the fluid and applied in combination with jetting of the fluid to print the top surface 705. The ASA may be employed to introduce an area of weakness that is useful for separating the part (not shown) that is printed in the coupled arrangement with the anchoring component 724 after sintering.

[00145] Other suitable techniques for forming a sinter-resistant layer on a sinterable three- dimensional object are described by way of non-limiting examples, in Khoshnevis, et al ., "Metallic part fabrication using selective inhibition sintering (SIS)," Rapid Prototyping Journal, Vol. 18:2, pp. 144-153 (2012) and U.S. Pat. No. 7,291,242 to Khoshnevis, each of which is hereby incorporated by reference in its entirety. By way of non-limiting example, suitable techniques for inhibiting sintering on a surface of an object include the use of a ceramic as a macroscopic mechanical inhibitor, an application of lithium chlorate and aluminum sulfate as microscopic mechanical inhibitors, and an application of sulfuric acid and hydrogen peroxide as chemical inhibitors. More generally, any technique for

mechanically, chemically or otherwise inhibiting sintering may be usefully employed to form the sinter-resistant layer to facilitate post-sintering separation of the part and the anchoring component 724.

[00146] FIG. 7C is a block diagram of another example embodiment of a part 710 printed in a coupled arrangement with an anchoring component 724. In the coupled arrangement of the example embodiment, the anchoring component 724 is printed underneath the part 710. The anchoring component 724 is formed with a feature that provides a resistive force to a spreading force imposed by a spreading mechanism (not shown). After the anchoring component 724 is at least some number of layers in thickness (at least one layer, preferably at least 10 layers, most preferably at least 30 layers), the feature is formed, an ASA is applied to the top surface 705 of the anchoring component 724, and the part is printed. The ASA forms a direct anchor coupling between the part 710 and the anchoring component 724, in the example embodiment. The coupled arrangement in combination with the resistive force, locks the printed part 710 in place in the powder bed 720 and the part 710 has reduced layer shifting and smearing due to its coupled arrangement with the anchoring component 724.

[00147] FIGS. 8A-D, disclosed below, disclose example embodiments of coupled arrangements of parts and anchoring components.

[00148] FIG. 8A is a block diagram of an example embodiment of a coupled arrangement of a part 810 and an anchoring component 824. In the example embodiment, the anchoring component 824 ( i.e raft) is under the part 810 and separated from the part 810 by an indirect anchor coupling 805 formed of a layer of loose {i.e., unbound) powder 804. In the example embodiment, at least a portion of the part 810 is printed above the anchoring component 824 and the at least a portion is the entire part 810. The anchoring component and the part 810 are printed parts, that is, formed of bound powder 833.

[00149] FIG. 8B is a block diagram of an example embodiment of a coupled arrangement of a part 810 and an anchoring component 824. In the example embodiment, the anchoring component 824 {i.e., raft) is under the part 810 and separated from the part 810 by an indirect anchor coupling 805 formed of a layer of loose {i.e., unbound) powder 804. At least a portion of the part 810 is printed above the anchoring component 824 and the anchoring component 824 is printed with a component shape that extends laterally beyond a lateral boundary of the part 810.

[00150] FIG. 8C is a block diagram of an example embodiment of a coupled arrangement of a part 810 and an anchoring component 824. In the example embodiment, the anchoring component 824 ( i.e raft) is under the part 810 and separated from the part 810 by an indirect anchor coupling 805 formed of a layer of loose {i.e., unbound) powder 804. At least a portion of the part 810 is printed above the anchoring component 824 and the anchoring component 824 is printed with a component shape that extends laterally beyond a lateral boundary of the part 810. One or more layers of the anchoring component 824 and the part 810 extend vertically upward and alongside each other.

[00151] FIG. 8D is a block diagram of an example embodiment of a coupled arrangement of a part 810 and an anchoring component 824. In the example embodiment, an anchoring component 824 {i.e., raft) is under the part 810 and separated from the part 810 by an indirect anchor coupling 805 formed of a layer of loose {i.e., unbound) powder 804. The anchoring component 824 is created with a gap 837 of the unbound powder 804 to facilitate decoupling of the anchoring component 824 from the part 810. The gap 837 may be referred to interchangeably herein as a“split.” The split may completely divide the anchoring component 824 into two or more separate bodies. The anchoring component 824 and the part 810 are printed parts formed of the bound powder 833.

[00152] FIGS. 9A-D disclose example embodiments of various geometries for the anchoring component of the coupled arrangements disclosed above in FIGS. 8A-D. The example embodiment of FIGS. 9A-D illustrate arbitrary shapes for the anchoring component {i.e., raft) 924 that follow a surface topology of the part 910. The anchoring component 924 and the part 910 are printed parts formed of the bound powder 933. An indirect anchor coupling formed of the unbound powder 904 is created between the anchoring component 924 and the part 910. As in the example embodiment of FIG. 8D, disclosed above, in the example embodiment of FIG. 9D, there is a gap 937 in the anchoring component 924.

[00153] It should be understood that the example embodiments of FIGS. 8A-9D may be combined with an ASA layer between the anchoring component and the part, such as disclosed with reference to FIG. 7B and FIG. 7C, above. [00154] FIG. 10A is a block diagram of an example embodiment of a part 1010 and an anchoring component 1024 printed as a multi-member structure. The part 1010 has multiple downward-facing surfaces 1011. Such downward-facing surfaces 1011 may be referred to interchangeably herein as“anchoring component-facing surfaces” of the part. In the example embodiment, the part 1010 and the anchoring component 1024 are printed in a coupled arrangement. The part 1010 and the anchoring component 1024 are formed of bound powder 1033. Printing of the anchoring component 1024 includes jetting the fluid into the unbound powder 1004 in a manner that formed the anchoring component 1024 as the multi-member structure. The part 1010 and the anchoring component 1024, printed as the multi-member structure, are separated by an indirect anchor coupling 1005 formed of a layer of loose (i.e., unbound) powder 1004. The multi-member structure may be separated from the part 1010 by one or more layers of unbound powder (also referred to interchangeably herein as loose powder), by a layer of ASA 1039 as disclosed in FIG. 10C, below, or may be connected to the part via a direct anchor coupling, as disclosed in FIG. 10B.

[00155] FIG. 10B is a block diagram of another example embodiment of a part 1010 and an anchoring component 1024 printed as a multi-member structure. In the example embodiment, the multi-member structure is connected to the part 1010 via multiple direct connections that form a direct anchor coupling between the part 1010 and the anchoring component 1024.

[00156] FIG. 10C is a block diagram of another example embodiment of a part 1010 and an anchoring component 1024 printed as a multi-member structure. In the example embodiment, the multi-member structure is separated from the part 1010 by an ASA layer that is formed by the ASA 1039 having been applied at multiple locations of the multi- member structure to form the anchor coupling 1005 that is a direct anchor coupling between the part 1010 and the anchoring component 1024 in the example embodiment.

[00157] FIG. 11 A is a screen view of an example embodiment of a multi-member structure 1121. As disclosed above, such a multi-member structure is not a contiguous body and may be employed as an anchoring component in a coupled arrangement with a part, such as the anchoring component 24 in the coupled arrangement 26 with the part 10 of FIG. 1B, disclosed above. Alternatively, the multi-member structure 1121 may be employed as an anchor coupling between the part and the anchoring component, such as the anchor coupling 5 between the part 10 and the anchoring component 24 of FIG. 1B, disclosed above. For example, the multi-member structure 1121 may be printed to form a direct anchor coupling between an anchoring component and part in a coupled arrangement, as disclosed above with reference to FIG. 6C.

[00158] FIG. 11B is an oblique view of an example embodiment of a part 1110 and a multi-member structure 1121. The multi-member structure 1121 includes multiple members that are crossed and connected and may be referred to herein as a lattice structure. The multiple members that are crossed and connected may include multiple horizontal and vertical members, such disclosed the horizontal member 1125 and the vertical member 1123. Alternatively, the multiple members that are crossed and connected may not be perpendicular with one another and may be arranged in regular or random pattern. The multi-member structure 1121 may be employed as an anchoring component in a coupled arrangement with the part 1110 or as an anchor coupling, or portion thereof, that is formed between the part 1110 and the anchoring component, as disclosed above. According to an example

embodiment, member thickness of members of the multi-member structure may be between 0.1 mm and 10 mm, more preferably between 0.5 mm and 3 mm, and most preferably between 0.8 mm and 1.2 mm. It should be understood, however, that member thickness may be any suitable member thickness and is not limited to thickness dimensions disclosed herein. According to an example embodiment, member spacing may be between 0.5 mm and 30 mm, more preferably between 3 mm and 10 mm. It should be understood, however, that member spacing may be any suitable member spacing and is not limited to spacing dimensions disclosed herein. The multi-member structure 1121 may have a direct anchor coupling with the part 1110, such as shown in FIG. 11C, disclosed below. Alternatively, the multi -member structure 1121 may have an indirect anchor coupling with the part 1110, such as shown in FIG. 11D, disclosed further below.

[00159] In the example embodiment of FIG. 11B, the multi-member structure is a cubic lattice. Such a cubic lattice is shown as an example embodiment due to ease of visualization and description. In general, a multi-member structure should be understood to encompass any regular or non-regular assembly of members that provide an anchoring force, that is, the resistive force that is sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism. [00160] According to an example embodiment, the multi-member structure may be a tree structure, wherein a single "trunk" of the tree structure connects to the anchoring component, and one or more "branches" of the tree structure join between the trunk and the part.

[00161] According to an example embodiment, the multi-member structure may include conical or cylindrical members that connect the anchoring component with the part.

Members of the multi-member structure may be oriented in a "vertical" orientation (z.e., normal to the layers or normal to a top surface of a layer after it has been spread by the spreading mechanism), or may be oriented to connect to the part in a direction that is normal to a surface of the part at the connection point, or may be oriented in any other suitable orientation to provide the anchoring force.

[00162] FIG. 11C is a cross-sectional view of an example embodiment of the part 1110 and multi-member structure 1121 of FIG. 11B, disclosed above. In the example embodiment of FIG. 11C, the multi-member structure 1121 has been printed such that it is coupled, directly, to the part 1110.

[00163] FIG. 11D is a cross-sectional view of another example embodiment of the part 1110 and multi-member structure 1121 of FIG. 11B, disclosed above. In the example embodiment of FIG. 11D, at least one layer of unbound powder 1104 has been formed between the part 1110 and the multi-member structure 1121. The part 1110 and the multi- member structure 1121 are indirectly coupled via the at least one layer of unbound powder 1104.

[00164] FIG. 12 is a block diagram of an example embodiment of a part 1210 in an arrangement with multiple anchoring components l224a and l224b. As disclosed in FIG. 12, creating an anchoring component to prevent smearing on downward-facing surfaces can be applied to any downward-facing surfaces of the part 1210, not just the bottom of the part 1210. Each of the multiple anchoring components l224a and l224b may have a direct or indirect anchor coupling with a respective anchoring component-facing surface of the part 1210, that is, the downward-facing surfaces 121 la and 121 lb, in the example embodiment.

In the example embodiment, the downward-facing surfaces 121 la and 121 lb are indirectly coupled with the anchoring components l224a and l224b, respectively, via the unbound powder 1204. The part 1210 and the anchoring components l224a and l224b are formed of the bound powder 1233. [00165] Referring back to FIG. 1B, the part 10 may have a part shape. Printing the anchoring component 24 may include printing the anchoring component 24 with a complementary shape relative to the part shape. The complementary shape may conform to a topography of the part shape to provide for the coupled arrangement.

[00166] FIG. 13 A is a block diagram of an example embodiment of a part 1310 with a part shape that includes multiple downward-facing surfaces 1311. FIG. 13B and FIG. 13C, disclosed below, disclose embodiments of a method for creating a 3D computer-aided design (CAD) model of the coupled arrangement based on the part shape of the part.

[00167] FIG. 13B is a block diagram of an example embodiment of the part 1310 of FIG.

13 A and a translated copy 1314 of the part 1310. The method for creating a 3D computer- aided design (CAD) model of the coupled arrangement may include duplicating a 3D model of the part 1310 to produce a copy of the 3D model of the part and translating the copy in a given direction to produce the translated copy 1314. The method may further comprise performing a 3D Boolean subtraction to subtract the 3D CAD model if the part 1310 from the translated copy 1314 to produce a 3D model of the anchoring component; and applying an offset 1325 between the 3D model of the part and the 3D model of the anchoring component.

[00168] FIG. 13C is a block diagram of an example embodiment of a result 1324 that results from performing the 3D Boolean subtraction to subtract the 3D model of the part 1310 from the translated copy 1314 to produce a 3D model of the anchoring component; and applying an offset between the 3D model of the part and the 3D model of the anchoring component. A coupled arrangement of the part and the anchoring component may be printed according to the 3D model of the part and the 3D model of the anchoring component.

[00169] FIG. 14A is a block diagram of another example embodiment of a part 1410 with a part shape that includes multiple downward-facing surfaces 1411. FIG. 14B-D, disclosed below, disclose embodiments of another method for creating a 3D model of a coupled arrangement based on the part shape of the part.

[00170] FIG. 14B is a block diagram of an example embodiment of an approximated version 1416 of the part 1410 of FIG. 14 A. The method for creating the 3D model of the coupled arrangement based on the part shape of the part 1410 may comprise approximating surfaces of a 3D CAD model of the part 1410 to produce and approximated version 1416. According to an example embodiment, the approximated version 1416 may be offset from the 3D CAD model of the part 1410 in an outward direction via the offset 1425. According to an example embodiment the approximated version 1416 may be of a given shape that has a larger volume and/or lower surface area relative to a volume and surface area of the part 1410.

[00171] FIG. 14C is a block diagram of an example embodiment of a translated approximated version 1414 of the approximated version 1416 of FIG. 14B. The method for creating the 3D model of the coupled arrangement may comprise translating the

approximated version 1416 in a given direction to produce the translated approximated version 1416. The method may further comprise performing a 3D Boolean subtraction to subtract the approximated version 1416 from the translated approximated version 1414.

[00172] FIG. 14D is a block diagram of an example embodiment of a result 1424 from a 3D subtraction performed to subtract the approximated version 1416 from the translated approximated version 1414 with an offset applied thereto. The result 1424 may be used as a model for printing the anchoring component. As such, anchoring components may be printed for parts with complex features on the downward facing surfaces by printing the anchoring component with features that, while complementary, do not interlock. Such interlocking features may be difficult to de-powder and/or may make it difficult to separate the part from the anchoring component.

[00173] A modeler, such as the modeler 153 of FIG. 1A, disclosed above, may be configured to perform a computer-implemented method for producing commands to drive a 3D printing system, such as the 3D printing system 250 of FIG. 2A, disclosed further above. The method may comprise producing a 3D computer-aided design (CAD) model of an anchoring component as a function of a 3D CAD model of a part. The model of the anchoring component may include a feature that provides a resistive force to a spreading force imposed by a spreading mechanism of the 3D printing system. The method may comprise producing commands as a function of the model of the part and the model of the anchoring component. The commands, when followed by the 3D printing system, may cause the spreading mechanism to spread unbound powder to form layers of a powder bed and may cause a printing mechanism of the 3D printing system to jet fluid into layers of the unbound powder to print the part in a coupled arrangement with the anchoring component formed with the feature. The coupled arrangement in combination with the resistive force is sufficient to at least partially immobilize at least one printed layer of the part in the powder bed to resist the spreading force imposed by the spreading mechanism during spreading of the unbound powder above the at least one printed layer of the part.

[00174] The feature of the anchoring component may be a given number of printed layers, an inverse geometric feature that complements a geometric feature of the part, or a combination thereof.

[00175] Producing the model of the anchoring component may include duplicating the model of the part to produce a copy of the model of the part, translating the copy in a given direction to produce a translated version of the copy, performing a 3D Boolean subtraction to subtract the copy of the model of the part, or the model of the part, from the translated version of the copy to produce the 3D model of the anchoring component, and applying an offset between the 3D model of the part and the 3D model of the anchoring component. Producing the commands may be further take into account the offset applied.

[00176] Producing the model of the anchoring component may include approximating edges and surfaces of the model of the part to produce an approximated version of the part. According to an example embodiment, the approximated version may be offset from the model of the part in an outward direction. According to an example embodiment the approximated version may be of a given shape that has a larger volume and/or lower surface area relative to a volume and surface area of the part. Producing the model may include translating the approximated version in a given direction to produce a translated version of the approximated version, performing a 3D Boolean subtraction to subtract the approximated version from the translated version to produce the 3D model of the anchoring component. Producing the anchoring component may include applying an additional offset between the 3D model of the part and the 3D model of the anchoring component. Producing the commands may take into account the additional offset, if applied.

[00177] Referring back to FIG. 1 A, the modeler 153 may be configured to employ a part description to produce a 3D CAD model of a part and may produce a 3D CAD model of an anchoring component that, in a coupled arrangement with the part, at least partially immobilizes the part to prevent defects in the part otherwise caused by a spreading force imposed by a spreading mechanism, as disclosed above. According to an example embodiment, the modeler 153 may append the model of the anchoring component to the model of the part (also referred to interchangeably herein as an object model) to create the printer instructions 157. Producing the model of the anchoring component may be based on information concerning a type of powder material employed, dimensions of the object model size, target speed for operating the spreading mechanism, target feature resolution, target surface finish, target cost, or a combination thereof.

[00178] According to an example embodiment, producing of the model of the anchoring component may be based on one or more powder properties. Such powder properties may include, but are not limited to: alloy, particle size distribution, presence of flow additives, powder temperature, powder history ( e.g ., baking cycles), use of recycled powder, density of powder in the powder bed (either measured actively or estimated from previous

measurements), measurement of powder flowability (e.g., Hall flow measurement, Freeman flow energy measurement, or other measurements), or a combination thereof.

[00179] According to an example embodiment, producing the model of the anchoring component may be based on geometrical properties of the part that is being protected from the spreading forces by the anchoring component. Such geometrical properties may include, but are not limited to: part size (e.g, longest dimension, shortest dimension, aspect ratio, etc.), overhang angle of downward facing surfaces on part, part orientation, location of the part within the powder bed (e.g, near bottom of powder bed, near top, near edges, in center, etc.), proximity to neighboring parts, or a combination thereof.

[00180] According to an example embodiment, producing the model of the anchoring component may be based on printing parameters. Such printing parameters may include, but are not limited to: binder being printed (e.g, aqueous versus non-aqueous), wetting properties of the powder and/or binder, whether or not drying is performed during printing, whether or not steaming is employed during printing, such as disclosed in U.S. Provisional Application No. 62/615,091, filed on January 9, 2018, the entire teachings of which are incorporated herein by reference, cycle time of the printer (i.e., time between layers), printing direction (e.g, bi-directional versus uni-directional), powder spreading method (e.g, counter-rotating roller, recoater blade, etc.), speed of the spreading mechanism (e.g, lateral traversing speed along the powder bed, rotational speed of spreading element, etc.), environmental parameters (e.g, ambient temperature, humidity, oxygen concentration, etc.), or a combination thereof. [00181] According to an example embodiment, producing the 3D model of the anchoring component may be based on a method to be employed for separating the part from the anchoring component. Such a separation method may include, but is not limited to: printing ASA between a part and its support, leaving unbound powder between the part and anchoring component, or a combination thereof.

[00182] FIG. 15A is a block diagram of another example embodiment of a coupled arrangement of a part 1510 and an anchoring component 1524. In the example embodiment, the anchoring component 1524 is printed at a lower saturation level than the part 1510. The anchoring component may be printed from powder material that is bound only lightly. In the example embodiment, a separation layer between the part 1510 and the“lightly bound” powder, that is, the anchoring component 1524, is loose {i.e., unbound) powder that forms an indirect anchor coupling between the part 1510 and the anchoring component 1524.

[00183] FIG. 15B is a block diagram of another example embodiment of a coupled arrangement of a part 1510 and an anchoring component 1524. In the example embodiment, the anchoring component 1524 is printed at a lower saturation level than the part 1510. The anchoring component may be printed from powder material that is bound only lightly. In the example embodiment, a separation layer between the part 1510 and the“lightly bound” powder, that is, the anchoring component 1524, is loose (i.e., unbound) powder and the anchoring component 1524 surrounds the part 1510 and forms an indirect anchor coupling between the part 1510 and the anchoring component 1524.

[00184] FIG. 15C is a block diagram of another example embodiment of a coupled arrangement of part 1510 and an anchoring component 1524. In the example embodiment, the anchoring component 1524 is printed at a lower saturation level than the part 1510. The anchoring component may be printed from powder material that is bound only lightly. In the example embodiment, there is no separation layer between the part 1510 and the“lightly bound” powder, that is, the anchoring component 1524. The part 1510 and the anchoring component 1524 have a direct anchor coupling formed between the bound powder of the part 1510 and the“lightly bound” powder of the anchoring component 1524.

[00185] FIG. 15D is a block diagram of another example embodiment of a coupled arrangement of part 1510 and an anchoring component 1524. In the example embodiment, the anchoring component 1524 is printed at a lower saturation level than the part 1510. The anchoring component may be printed from powder material that is bound only lightly. In the example embodiment, there is no separation layer between the part 1510 and the“lightly bound” powder, that is, the anchoring component 1524, and the anchoring component 1524 surrounds the part 1510. The part 1510 and the anchoring component 1524 have a direct anchor coupling formed between the bound powder of the part 1510 and the“lightly bound” powder of the anchoring component 1524.

[00186] According to the example embodiments of FIGS. 15A-D, disclosed above, fluid may be printed (i.e., jetted) into the powder bed beneath and/or surrounding the part, at a lower concentration (saturation level) than is required to fully bind the powder together, effectively locking the powder in place and preventing layer shifting. After

drying/crosslinking, the“lightly bound” powder would not be held together and, thus, could be removed (i.e., de-coupled) from the printed part. Such a method could be applied using a separation layer between the part and the“lightly bound” powder, that is, the anchoring component, or with no separation therebetween.

[00187] FIG. 16A is an image of an example embodiment of a portion of a part 1610 with layer shifting.

[00188] FIG. 16B is an image of an example embodiment of the part 1610 of FIG. 16A without layer shifting and an anchoring component 1624.

[00189] FIG. 16C is an image of the example embodiment of the part 1610 of FIG. 16B without layer shifting.

[00190] FIG. 17 is a block diagram of an example of the internal structure of a computer 1700 in which various embodiments of the present disclosure may be implemented. The computer 1700 contains a system bus 1702, where a bus is a set of hardware lines used for data transfer among the components of a computer or processing system. The system bus 1702 is essentially a shared conduit that connects different elements of a computer system e.g ., processor, disk storage, memory, input/output ports, network ports, etc) that enables the transfer of information between the elements. Coupled to the system bus 1702 is an I/O device interface 1704 for connecting various input and output devices (e.g., keyboard, mouse, displays, printers, speakers, etc.) to the computer 1700. A network interface 1706 allows the computer 1700 to connect to various other devices attached to a network. Memory 1708 provides volatile or non-volatile storage for computer software instructions 1710 and data 1712 that may be used to implement embodiments of the present disclosure, where the volatile and non-volatile memories are examples of non-transitory media. Disk storage 1714 provides non-volatile storage for computer software instructions 1710 and data 1712 that may be used to implement embodiments of the present disclosure. A central processor unit 1718 is also coupled to the system bus 1702 and provides for the execution of computer instructions.

[00191] Further example embodiments disclosed herein may be configured using a computer program product; for example, controls may be programmed in software for implementing example embodiments. Further example embodiments may include a non- transitory computer-readable medium containing instructions that may be executed by a processor, and, when loaded and executed, cause the processor to complete methods described herein. It should be understood that elements of the block and flow diagrams may be implemented in software or hardware, such as via one or more arrangements of circuitry of FIG. 17, disclosed above, or equivalents thereof, firmware, a combination thereof, or other similar implementation determined in the future. In addition, the elements of the block and flow diagrams described herein may be combined or divided in any manner in software, hardware, or firmware. If implemented in software, the software may be written in any language that can support the example embodiments disclosed herein. The software may be stored in any form of computer readable medium, such as random access memory (RAM), read only memory (ROM), compact disk read-only memory (CD-ROM), and so forth. In operation, a general purpose or application-specific processor or processing core loads and executes software in a manner well understood in the art. It should be understood further that the block and flow diagrams may include more or fewer elements, be arranged or oriented differently, or be represented differently. It should be understood that implementation may dictate the block, flow, and/or network diagrams and the number of block and flow diagrams illustrating the execution of embodiments disclosed herein.

[00192] The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.

[00193] While example embodiments have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the embodiments encompassed by the appended claims.