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Title:
SYSTEM AND METHOD FOR CONTINUOUS ADDITIVE MANUFACTURING
Document Type and Number:
WIPO Patent Application WO/2019/190467
Kind Code:
A1
Abstract:
A manufacturing cell for manufacturing a continuous component includes an additive manufacturing implement operable between a first position and a second position to additively build a first portion of the component, the first position and the second position defining the working envelope of the additive manufacturing implement in a first direction. A conveyor is positioned adjacent the additive manufacturing implement and is operable to move the component in the first direction such that the first portion of the component extends outside of the working space between the first position and the second position during operation of the additive manufacturing implement to form a second portion of the component.

Inventors:
BRUCK GERALD J (US)
Application Number:
US2018/024421
Publication Date:
October 03, 2019
Filing Date:
March 27, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SIEMENS ENERGY INC (US)
International Classes:
B22F3/105; B22F3/11; B22F3/17; B22F7/02; B28B1/00; B65G15/00; B65G17/00; B65G21/08; B65G47/16
Domestic Patent References:
WO2017050860A12017-03-30
Foreign References:
US5269982A1993-12-14
US20170291260A12017-10-12
Other References:
None
Attorney, Agent or Firm:
OTTERLEE, Thomas J. (US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A manufacturing cell for manufacturing a continuous component, the

manufacturing cell comprising:

an additive manufacturing implement operable between a first position and a second position to additively build a first portion of the component, the first position and the second position defining the working envelope of the additive manufacturing implement in a first direction; and

a conveyor positioned adjacent the additive manufacturing implement and operable to move the component in the first direction such that the first portion of the component extends outside of the working envelope between the first position and the second position during operation of the additive manufacturing implement to form a second portion of the component.

2. The manufacturing cell of claim 1, wherein the additive manufacturing implement is arranged to facilitate additive manufacture using one of a laser, an electron beam, and a plasma beam.

3. The manufacturing cell of claim 1 , wherein the conveyor moves the component in a linear direction to move the first portion of the component out of the working envelope.

4. The manufacturing cell of claim 1 , wherein the conveyor rotates about an axis to rotate the first portion of the component out of the working envelope.

5. The manufacturing cell of claim 1 , further comprising a hopper positioned to deliver a powder to a powder bed, the powder selected to interact with the additive

manufacturing implement to form the component.

6. The manufacturing cell of claim 5, wherein the powder includes a powdered metal.

7. The manufacturing cell of claim 5, further comprising a screeder positioned between the hopper and the additive manufacturing implement and movable with respect to the conveyor to level the powder bed.

8. The manufacturing cell of claim 7, wherein the screeder moves in a second direction that is normal to the first direction.

9. The manufacturing cell of claim 5, wherein the conveyor supports the powder bed.

10. The manufacturing cell of claim 5, further comprising a fluidizing device coupled to the container and operable to fluidize and level the powder bed.

11. The manufacturing cell of claim 1 , further comprising an enclosure that substantially encloses the additive manufacturing implement and the working envelope, and wherein the enclosure contains an atmosphere therein.

12. The manufacturing cell of claim 11, wherein the atmosphere is one of a vacuum or a gas mixture including at least 80 percent inert gas.

13. The manufacturing cell of claim 11, wherein the enclosure cooperates with the conveyor to define a passage sized to receive the component.

14. The manufacturing cell of claim 13, further comprising a seal device positioned adjacent the passage and operable to maintain the atmosphere within the enclosure.

15. The manufacturing cell of claim 1, further comprising a second additive manufacturing implement positioned adjacent the additive manufacturing implement, wherein the additive manufacturing implement adds a first layer to the component and the second additive manufacturing implement adds a second layer to the component.

16. A method of additively manufacturing a component, the method comprising: positioning a layer of powdered material on a conveyor;

operating an additive manufacturing implement to form a first portion of the component within the layer of powder, the additive manufacturing implement operable within a working envelope;

forming a layer of powder material on the conveyor adjacent the first portion of the component;

moving the conveyor to reposition the first portion of the component at least partially outside of the working envelope; and

operating the additive manufacturing implement to form a second portion of the component within the layer of powder, the first portion of the component and the second portion of the component being connected to one another such that the component is one continuous piece of material.

17. The method of claim 16, further comprising screeding the layer of powder to level the powder.

18. The method of claim 16, further comprising positioning an enclosure around the additive manufacturing implement and the working space and forming a desired atmosphere within the enclosure.

19. The method of claim 18, wherein the desired atmosphere is one of a vacuum and a gas mixture including at least 80 percent inert gas.

20. The method of claim 18, further comprising passing at least a portion of the first portion of the component outside of the working envelope before forming the second portion of the component.

21. The method of claim 18, further comprising passing at least a portion of the first portion of the component outside of the enclosure before forming the second portion of the component. 22 The method of claim 16, wherein operating the additive manufacturing implement includes one of forming a laser, activating an electron beam, and forming a plasma.

Description:
SYSTEM AND METHOD FOR CONTINUOUS ADDITIVE MANUFACTURING

TECHNICAL FIELD

[0001] The present disclosure is directed, in general, to additive manufacturing and more specifically to additive manufacturing of metallic components.

BACKGROUND

[0002] Additive manufacturing includes a number of manufacturing processes that operate by adding layers of material to build a component or part. Many different processes exist and are often tailored to the type of material being used. Additive manufacturing is often used to build complex shapes or structures that would be difficult to make using traditional forming and removal processes (e.g., casting and machining). In addition, where material costs are significant, additive manufacturing may be useful in forming parts to reduce the material waste and cost.

SUMMARY

[0003] A manufacturing cell for manufacturing a continuous component includes an additive manufacturing implement operable between a first position and a second position to additively build a first portion of the component, the first position and the second position defining the working envelope of the additive manufacturing implement in a first direction. A conveyor is positioned adjacent the additive manufacturing implement and is operable to move the component in the first direction such that the first portion of the component extends outside of the working space between the first position and the second position during operation of the additive manufacturing implement to form a second portion of the component.

[0004] In another construction, a method of additively manufacturing a component includes positioning a layer of powdered material on a conveyor, and operating an additive manufacturing implement to form a first portion of the component within the layer of powder, the additive manufacturing implement operable within a working envelope. The method also includes forming a layer of powder material on the conveyor adjacent the first portion of the component, moving the conveyor to reposition the first portion of the component at least partially outside of the working envelope, and operating the additive manufacturing implement to form a second portion of the component within the layer of powder, the first portion of the component and the second portion of the component being connected to one another such that the component is one continuous piece of material.

[0005] The foregoing has outlined rather broadly the technical features of the present disclosure so that those skilled in the art may better understand the detailed description that follows.

Additional features and advantages of the disclosure will be described hereinafter that form the subject of the claims. Those skilled in the art will appreciate that they may readily use the conception and the specific embodiments disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Those skilled in the art will also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure in its broadest form.

[0006] Also, before undertaking the Detailed Description below, it should be understood that various definitions for certain words and phrases are provided throughout this specification, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases. While some terms may include a wide variety of embodiments, the appended claims may expressly limit these terms to specific embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Fig. 1 is a schematic illustration of a manufacturing cell including a conveyor and an additive manufacturing implement.

[0008] Fig. 2 is a top view of one possible component manufactured by the manufacturing cell of claim 1. [0009] Fig. 3 is a schematic illustration of a manufacturing cell similar to that of Fig. 1 including a rotating conveyor.

[0010] Fig. 4 is a schematic illustration of a manufacturing system including two of the manufacturing cells of Fig. 1.

[0011] Fig. 5 is an enlarged view of a portion of the system taken inside of line 5-5.

[0012] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

[0013] Various technologies that pertain to systems and methods will now be described with reference to the drawings, where like reference numerals represent like elements throughout.

The drawings discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged apparatus. It is to be understood that functionality that is described as being carried out by certain system elements may be performed by multiple elements. Similarly, for instance, an element may be configured to perform functionality that is described as being carried out by multiple elements. The numerous innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0014] Also, it should be understood that the words or phrases used herein should be construed broadly, unless expressly limited in some examples. For example, the terms“include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The singular forms“a”,“an” and“the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, the term“and/or” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term“or” is inclusive, meaning and/or, unless the context clearly indicates otherwise. The phrases “associated with” and“associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like.

[0015] Also, although the terms "first", "second", "third" and so forth may be used herein to refer to various elements, information, functions, or acts, these elements, information, functions, or acts should not be limited by these terms. Rather these numeral adjectives are used to distinguish different elements, information, functions or acts from each other. For example, a first element, information, function, or act could be termed a second element, information, function, or act, and, similarly, a second element, information, function, or act could be termed a first element, information, function, or act, without departing from the scope of the present disclosure.

[0016] In addition, the term "adjacent to" may mean: that an element is relatively near to but not in contact with a further element; or that the element is in contact with the further portion, unless the context clearly indicates otherwise. Further, the phrase“based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.

[0017] Fig. 1 schematically illustrates a manufacturing cell 10 for use in manufacturing a component, part, or a feature on a component (hereinafter referred to as a component 15) such as the one illustrated in Fig. 2 using an additive manufacturing process. The manufacturing cell 10 includes a conveyor 20 movable in a first direction 25, a powder bed 30, a screeder 35, a hopper 40, an additive manufacturing implement 45, and an enclosure 50.

[0018] As one of ordinary skill will understand, many additive manufacturing techniques are known. Many of the known techniques manufacture a component 15 by adding layers in a layer by layer fashion. The additive manufacturing implement 45 of Fig. 1 forms a layer in a two dimensional working space or envelope 52 (length and width) with the layer extending in the third or thickness dimension 55. Each layer is typically between 0.02 mm and 2 mm with other layer thicknesses being possible. Multiple layers can be formed within the length and width envelope 52 until the component 15 is completed.

[0019] The additive manufacturing implement 45 illustrated in Fig. 1 includes an emitter 60 or head suitable for use in an additive manufacturing process such as selective laser sintering (SLS), selective laser melting (SLM), electron beam, or other similar techniques. In some

constructions, the emitter 60 is movable in length and width directions to define the two dimensional envelope 52 within which the emitter 60 is operable to complete a layer of the component 15. In other constructions, emissions such as laser light or an electron beam from the emitter 60 are projected by pivoting mirrors or electromagnetic coils to move a target point of directed energy within the envelope 52 to complete the layers of the component 15 being manufactured.

[0020] The powder bed 30 includes a container 65 and a quantity of powdered material 70 suited for use in the selected manufacturing process. In some powder beds 30, a divider 72 is positioned near the edge of the envelop 52 of the emitter 60. The divider 72 aids in supporting the powder 70 but allows the powder to be removed from one side. A drain or extraction port 73 is positioned downstream from the envelop 52 with respect to the first direction 25 to allow for the removal and reuse of unused powder 70. Specifically, the powder 70 is removed from the extraction port 73 and redirected to an inlet 74 that feeds powder 70 to the hopper 40. Of course, filters or other cleaning processes could be applied to the powder between the extraction port 73 and the inlet 74. The powder bed 30 supports the powder 70 at a desired height or position within the envelope 52 of the emitter 60 and collects any unused powder 70 for recirculation or reuse.

[0021] The hopper 40 is positioned above the powder bed 30 and arranged to deliver unused powder 70 from screeding, draining, and makeup powder to the powder bed 30. The screeder 35 is positioned adjacent the powder bed 30 and is movable to screed or level the layer of powder 70 within the powder bed 30. In the construction of Fig. 1, the screeder 35 moves in a direction normal to the first direction 25 (into and out of the plane of Fig. 1) with other systems including screeders that move in different directions. [0022] The conveyor 20 supports the component 15 being manufactured or modified and moves the component 15 in the first direction 25 during the process. The conveyor 20 includes a belt 75 that can support the component 15 and a layer of powder 70. The conveyor belt 75 can be manufactured from any material suitable for the manufacturing process. Many additive manufacturing processes create a significant amount of heat. For these processes, a conveyor belt 75 made from a ceramic material or heat tolerant fabric such as fiberglass, silicone cloth or Kevlar can be advantageous. In some constructions, the conveyor belt 75 moves in a continuous fashion while the emitter 60 completes a portion of a layer on the component 15. For example, the emitter 60 could move back and forth in a direction normal to the first direction 25 to complete narrow portions of the component 15 as the conveyor belt 75 continues to move.

Programming of energy projection is then coordinated with the rate of component 15 translation by the conveyor 20 in the first direction 25. In another construction, the emitter 60 completes a first portion of the component 15 that lies within the envelope 52 while the conveyor belt 75 is still, and then the conveyor belt 75 moves or increments the component 15 to position a new space with a fresh layer of powder 70 within the envelope 52. The emitter 60 then completes a second portion of the component 15 within this second space before further movement of the conveyor belt 75 occurs, with the first two formed portions being attached to one another as one continuous component.

[0023] In the construction illustrated in Fig. 1 , the conveyor belt 75 is powered by an electric motor 80 that is capable of driving the conveyor belt 75 at a constant speed, a variable speed, and/or that can start, stop, or reverse the conveyor belt 75 to increment or reposition the component 15. Of course other drive mechanisms other than the motor 80 are possible. It is also possible to refeed the component 15 back onto the conveyor belt 75 to build a second, third, etc. layer onto the previously deposited layer. Thin sheets of material such as the open mesh 15 shown in Fig. 2 could be readily looped back onto the conveyor belt 75. Stiffer sheets or plates could be simply refed.

[0024] The additive manufacturing implement 45 may include a computer 85 that can control the movement and operation (e.g., power level, focus, movement speed and direction, etc.) of the emitter 60. In some constructions, the computer 85 also controls the motor 80, or other drive mechanism, of the conveyor 20 to control the movement and speed of the conveyor belt 75. Outside sensors (not shown) may be included to provide feedback to the computer 85 to enhance or optimize the control of the emitter 60 and motor 80 or other drive mechanism.

[0025] The enclosure 50 at least partially encloses the envelope 52, some area around the conveyor 20, and the emitter 60. The enclosure 50 is substantially sealed so that a desired atmosphere can be established within the enclosure 50. The selected additive manufacturing process and materials often dictate the chemical make-up of the atmosphere. For example, laser processes often utilize an atmosphere of argon or nitrogen. Electron beam processes may require the atmosphere be evacuated to establish a desired vacuum pressure within the enclosure 50. Sealing shoes, brushes or curtains can be positioned at the open end 90 to preserve a vacuum barrier where the part 15 exits or enters the enclosure 50.

[0026] With continued reference to Fig. 1 , the enclosure 50 includes an open end 90 through which the component 15 passes. As illustrated in Fig. 5 one or more seals 92 can be positioned adjacent the open end 90 to assist in maintaining the desired atmosphere within the enclosure 50. In the illustrated construction, a simple flexible member is positioned to contact the enclosure 50 and the component 15 to form a seal. Other types of seals or additional seals may be positioned near the open end 90 to reduce the leakage into or out of the enclosure 50 to maintain the desired atmosphere. Returning to Fig. 1 , the computer 85 can also be configured to control the atmosphere within the enclosure 50. Sensors can be positioned to measure the make-up of the atmosphere and/or the pressure within the enclosure 50. The computer 85 can control valves to admit gasses as may be required to maintain the desired atmosphere and make up for losses. Alternatively, the computer 85 can activate vacuum pumps in response to excess pressure within the enclosure 50 to maintain the desired vacuum pressure within the enclosure 50.

[0027] To use the construction of Fig. 1 , the user first establishes the desired atmosphere within the enclosure 50. Appropriate powder 70 for the component 15 being made is delivered via the hopper 40 to the belt 75 of the conveyor 20. As the conveyor belt 75 moves in the first direction 25, the powder 70 passes under the screeder 35 while the screeder 35 moves normal to the first direction 25 to screed or level the layer of powder 70.

[0028] The computer 85 controls the operation and movement of the emitter 60 of the additive manufacturing implement 45 as well as the movement of the conveyor belt 75 to allow the emitter 60 to form a first row or portion of the component 15. The emitter 60 and conveyor belt 75 continue to move to manufacture the component 15 with the conveyor belt 75 moving more powder 70 into position. Eventually, the length of the component 15 exceeds the envelope 52 and part of the component 15 passes through the open end 90 of the enclosure 50. Once the first layer of the component 15 is complete, the component 15 can be repositioned at the opposite end of the conveyor belt 75 and the process repeated to form a second layer. This process could be repeated until the component 15 is complete. Such refeeding provides the additional opportunity to turn the part 15 over so that layers may be added to alternate surfaces of the part 15. This step could be of advantage in balancing shrinkage stresses from solidification and in minimizing heat buildup effects otherwise resulting from continual processing on the same surface. Similarly, the part 15 could be rotated before refeeding to avoid directional effects otherwise resulting from unidirectional processing.

[0029] Alternatively, as illustrated in Fig. 4 two or more manufacturing cells 10 as shown in Fig. 1 could be arranged in a line. A first cell lOa forms the first layer of material with each additional cell lOb adding a new layer to the component 15. In addition, several cells lOa, lOb could be arranged to form several layers of a component 15 and then that component 15 could be re-inserted at the first cell lOa to add several more layers until the component 15 is completed.

[0030] Fig. 3 illustrates another manufacturing cell 100 in which a conveyor 105 rotates a component 110 around an axis rather than moving the component 110 in a linear direction. In this construction, a powder bed 115 is contained within a container 120 and the component 110 and conveyor 105 are submerged and contained within the same container 120. A hopper 125 feeds powder 130 to the powder bed 1 15 as was done in the construction of Fig. 1. This process is particularly well-suited to adding features to an already existing cylindrical component.

[0031] A first screeder 135 moves parallel to the axis of rotation of the conveyor 105 (i.e., into and out of the plane of Fig. 3) to level the powder 130 within the powder bed 115. A second screeder (not shown) may be provided to further level the powder 130. The second screeder would move in a direction normal to the direction of movement of the first screeder 135 (i.e., left to right in Fig. 3) in front of the beam produced by an emitter 145. In addition to the use of screeders 135, a fluidizing device 138 could also be employed to level the powder 130. Fluidizing devices 138 may include a gas system that admits gas at a desired rate into the powder bed 115 to fluidize the powder 130 or may include vibratory mechanisms that vibrate the powder 130 at a desired frequency.

[0032] To use the construction of Fig. 3, the user again first establishes the appropriate atmosphere within an enclosure 140. The powder 130 is then added and screeded to establish the desired level of powder 130 at or near a top dead center position above the component 110. The emitter 145 moves axially or directs its energy beam along the length of the rotational axis to form the portions of the component 110 that are desired at or near the top dead center position. The conveyor 105 then rotates the component 110 to position the next area to be worked on at or near the top dead center position and the process is repeated. Once a first layer is completed and the component 110 has made a full revolution a second layer can be added. To add a second layer, either the rotational axis is lowered, or more preferably additional powder 130 is added to raise the level of powder to assure a desired thickness of powder 130 is positioned above the component 110 at or near the top dead center position. The manufacturing process is then repeated until the necessary number of revolutions is completed.

[0033] Another use of the construction illustrated in Fig. 3 provides for continuous processing by the emitter 145. In this arrangement, the conveyor 105 continuously rotates the component 110 as the emitter 145 moves or directs its energy beam along the rotational axis. The rate of rotation and the traversal speed of the emitter 145 or its directed beam are selected and controlled to assure that the surface being added at any given time is in the desired orientation and that no surface to be added rotates beyond the desired orientation before the emitter 145 can add the desired layer.

[0034] Although an exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will understand that various changes, substitutions, variations, and improvements disclosed herein may be made without departing from the spirit and scope of the disclosure in its broadest form.

[0035] None of the description in the present application should be read as implying that any particular element, step, act, or function is an essential element, which must be included in the claim scope: the scope of patented subject matter is defined only by the allowed claims. Moreover, none of these claims are intended to invoke a means plus function claim construction unless the exact words "means for" are followed by a participle.