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Title:
3D PRINTING POWDER AND 3D PRINTING METHOD
Document Type and Number:
WIPO Patent Application WO/2017/114852
Kind Code:
A1
Abstract:
The present invention provides a 3D printing powder and a 3D printing method, the 3D printing powder having a particle size in the range of 20 microns to 40 microns, each 3D printing powder being formed by aggregation of multiple powder base bodies having a particle size in the range of 0.2 microns to 1 micron. The 3D printing powder of the present invention can meet the requirements of a powder spreading process, and the components manufactured have a better surface finish and better mechanical properties. Furthermore, existing additive manufacturing equipment can manufacture a ceramic-based product using the 3D printing powder of the present invention.

Inventors:
CHEN GUO FENG (CN)
LI CHANG PENG (CN)
YAO ZHI QI (CN)
Application Number:
PCT/EP2016/082746
Publication Date:
July 06, 2017
Filing Date:
December 28, 2016
Export Citation:
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Assignee:
SIEMENS AG (DE)
International Classes:
B22F1/00; B22F3/105; B28B1/00; C04B35/626; B22F9/02
Domestic Patent References:
WO2015109658A12015-07-30
WO2015175726A12015-11-19
WO2016116562A12016-07-28
Foreign References:
EP2112127A12009-10-28
US20150321255A12015-11-12
CA2917038A12015-01-08
US20010005797A12001-06-28
EP3047926A22016-07-27
Other References:
BIKAS H ET AL: "Additive manufacturing methods and modelling approaches: a critical review", INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, SPRINGER VERLAG, LONDON; GB, vol. 83, no. 1, 24 July 2015 (2015-07-24), pages 389 - 405, XP035634368, ISSN: 0268-3768, [retrieved on 20150724], DOI: 10.1007/S00170-015-7576-2
Attorney, Agent or Firm:
ISARPATENT - PATENT- UND RECHTSANWÄLTE BEHNISCH BARTH CHARLES HASSA PECKMANN UND PARTNER MBB (München, DE)
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Claims:
Claims

1. A 3D printing powder (10), characterized in that the 3D printing powder (10) has a particle size (Dl) in the range of 20 microns to 40 microns, each 3D printing powder (10) being formed by aggregation of multiple powder base bodies (12), the powder base bodies (12) having a particle size (D2) in the range of 0.2 microns to 1 micron.

2. The 3D printing powder (10) as claimed in claim 1, characterized in that the 3D printing powder (10) is a metal powder or a ceramic powder.

3. The 3D printing powder (10) as claimed in claim 1 or 2, characterized in that the 3D printing powder (10) is a metal powder, and is a nickel-chromium-iron alloy.

4. The 3D printing powder (10) as claimed in any of the claims 1 to 3, characterized in that the 3D printing powder (10) is a precipitation-hardened nickel-chromium-iron alloy containing niobium and molybdenum.

5. The 3D printing powder (10) as claimed in any of the claims 1 to 4, characterized in that the 3D printing powder (10) is a ceramic powder, comprising at least one of a metal oxide, carbide and nitride.

6. A 3D printing method, characterized by comprising the following steps:

providing a 3D printing powder (10) and a 3D printing apparatus (300), the 3D printing powder (10) having a particle size (Dl) in the range of 20 microns to 40 microns, each 3D printing powder (10) being formed by aggregation of multiple powder base bodies (12) having a particle size (D2) in the range of 0.2 microns to 1 micron;

spreading the 3D printing powder (10) on a forming part (334) of the 3D printing apparatus (300);

using a laser beam emitted by the 3D printing apparatus (300) to scan and irradiate the 3D printing powder (10) on the forming part (334);

the 3D printing powder (10) is decomposed into the powder base bodies (12); the laser beam continues to irradiate the powder base bodies (12) until the powder base bodies (12) are sintered into a preset shape.

7. The 3D printing method as claimed in claim 6, characterized in that the 3D printing apparatus (300) comprises a laser (342) and a scanning lens (343); the laser (342) is connected to the scanning lens (343) , and can generate the laser beam; the scanning lens (343) uses the laser beam provided by the laser (342) to scan and irradiate the 3D printing powder (10) .

8. The 3D printing method as claimed in claim 6 or 7, characterized in that the 3D printing apparatus (300) also comprises a roller wheel (324); the 3D printing powder (10) is spread on the forming part (334) by the rolling of the roller wheel (324) .

Description:
Description

3D printing powder and 3D printing method Technical field

The present invention relates to the technical field of 3D printing, in particular a 3D printing powder and a 3D printing method which uses the powder.

Background art

Additive manufacturing technology is an important 3D printing technology. Additive manufacturing technology can rapidly manufacture a pre-designed CAD model, and is capable of manufacturing structurally complex components in a short time. Selective laser melting (SLM) technology is an additive manufacturing technology, which is capable of rapidly manufacturing components identical to CAD models by laser sintering. Selective laser melting technology is widely used at present .

However, selective laser melting technology still has many problems; for instance, to facilitate powder spreading, the powder used has a large particle size, and can only be melted by irradiation with a laser beam of high power. This increases the demands placed on selective laser melting equipment, components deform readily, and component surfaces are of poor quality. In general, components manufactured by selective laser melting technology must also be polished. When gas ducts are provided in the interior of a component, the inside surfaces of the gas ducts must also be polished. However, it is very difficult to polish the inside surfaces of gas ducts in a component. Furthermore, due to the large particle size of the powder, when the powder is a ceramic powder, the sintering temperature required is excessively high, and it is very difficult to manufacture a ceramic-based product directly using existing additive manufacturing equipment.

To solve this technical problem, in the prior art, the particle size of powder used in selective laser melting technology is generally reduced, but powder with too small a particle size readily agglomerates or flies up, so is not easy to spread.

Content of the invention

In view of the above, the object of the present invention is to propose a 3D printing powder and a 3D printing method. The 3D printing powder can meet the requirements of a powder spreading process, and the components manufactured have a better surface finish and better mechanical properties. Furthermore, since powder of a small size can melt at a lower temperature, not only can the requirements on equipment laser light source power be reduced, but ceramic-based products can be manufactured using an existing additive manufacturing process .

The present invention provides a 3D printing powder having a particle size in the range of 20 microns to 40 microns, each 3D printing powder being formed by aggregation of multiple powder base bodies having a particle size in the range of 0.2 microns to 1 micron.

In a schematic embodiment of the 3D printing powder, the 3D printing powder is a metal powder or a ceramic powder.

In a schematic embodiment of the 3D printing powder, the 3D printing powder is a metal powder, and is a nickel-chromium- iron alloy.

In a schematic embodiment of the 3D printing powder, the 3D printing powder is a precipitation-hardened nickel-chromium- iron alloy containing niobium and molybdenum.

In a schematic embodiment of the 3D printing powder, the 3D printing powder is a ceramic powder, comprising at least one of a metal oxide, carbide and nitride.

The present invention also provides a 3D printing method, comprising the following steps:

providing a 3D printing powder and a 3D printing apparatus, the 3D printing powder having a particle size in the range of 20 microns to 40 microns, each 3D printing powder being formed by aggregation of multiple powder base bodies having a particle size in the range of 0.2 microns to 1 micron;

spreading the 3D printing powder on a forming part of the 3D printing apparatus;

using a laser beam emitted by the 3D printing apparatus to scan and irradiate the 3D printing powder on the forming part; the 3D printing powder is decomposed into the powder base bodies; the laser beam continues to irradiate the powder base bodies until the powder base bodies are sintered into a preset shape .

In a schematic embodiment of the 3D printing method, the 3D printing apparatus comprises a laser and a scanning lens; the laser is connected to the scanning lens, and can generate the laser beam; the scanning lens uses the laser beam provided by the laser to scan and irradiate the 3D printing powder.

In a schematic embodiment of the 3D printing method, the 3D printing apparatus also comprises a roller wheel; the 3D printing powder is spread on the forming part by the rolling of the roller wheel.

It can be seen from the solution above that in the case of the 3D printing powder and 3D printing method of the present invention, the 3D printing powder has a large particle size and good flow properties, so can meet the requirements of a powder spreading process in selective laser melting technology. During powder spreading, the 3D printing powder does not readily aggregate or fly up. When the powder spreading process is complete, a laser beam irradiates the 3D printing powder, which can then decompose into powder base bodies of a smaller particle size, such that the component produced from the 3D printing powder of the present invention has a better surface finish and better mechanical properties. Furthermore, the ceramic powder of smaller particle size may also be sintered using an existing laser beam, so that a ceramic component can be manufactured using existing additive manufacturing equipment .

Description of the accompanying drawings

Preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, to give those skilled in the art a clearer understanding of the abovementioned and other features and advantages of the present invention. Drawings:

Fig. 1 is a schematic diagram of a 3D printing powder in an embodiment of the present invention.

Fig. 2 is a schematic diagram of the 3D printing powder shown in Fig. 1, from forming to decomposition.

Fig. 3 is a schematic diagram of a 3D printing apparatus which processes the 3D printing powder shown in Fig. 1.

Fig. 4 is a flow chart of a method for 3D printing using the 3D printing powder shown in Fig. 1.

The labels used in the abovement ioned accompanying drawings are as follows:

10 3D printing powder

12 powder base body

300 3D printing apparatus

component to be

301

processed

32 material supply unit

322 supply piston

323 first cylinder

324 roller wheel

33 forming unit

332 forming piston

333 second cylinder

334 forming part

34 laser sintering unit 342 laser 343 scanning lens

S41, S42, S43,

steps

S44

particle size of 3D

Dl

printing powder 10

particle size of powder

D2

base body 12

Particular embodiments

In order to clarify the object, technical solution and advantages of the present invention, the present invention is explained in further detail below by way of embodiments.

Fig. 1 is a schematic diagram of a metal or ceramic powder in an embodiment of the present invention. Fig. 2 is a schematic diagram of the metal or ceramic powder shown in Fig. 1, from forming to decomposition. Referring to Figs. 1 and 2, the particle size Dl of 3D printing powder 10 in this embodiment is in the range of 10 μιη to 60 μιη, preferably 20 - 40 μιη. Each 3D printing powder 10 is formed by aggregation of multiple powder base bodies 12; the particle size D2 of the powder base body 12 is in the range of 0.05 μιη to 5 μιη, preferably 0.2 μιη to 1 μιη.

The 3D printing powder 10 is a metal powder or a ceramic powder; the metal powder is for example Inconel 718 alloy, which is a precipitation-hardened nickel-chromium-iron alloy containing niobium and molybdenum, having high strength, good toughness and resistance to high temperatures. The ceramic powder is a ceramic material with a number of different structures and functions, and includes at least one of a metal oxide, a carbide and a nitride, i.e. the ceramic powder comprises one or more of a metal oxide, a carbide and a nitride. Furthermore, the 3D printing powder 10 may also be another nickel-chromium-iron ally or another material having high strength and resistance to high temperatures.

The 3D printing powder 10 may be prepared by the following method, but is not limited thereto.

First of all, the powder base bodies 12 may be produced by mechanical grinding, wherein the grinding time depends upon the particle size, material and grinding efficiency of the powder base bodies 12. The powder base bodies 12 may be immersed in a liquid such as liquid methanol or liquid nitrogen. A binder is also added to the liquid. The binder is an organic substance capable of binding together multiple powder base bodies 12. Next, a granulation process is performed by spray drying to produce a semi-finished product of 3D printing powder 10. The semi-finished product of 3D printing powder 10 is then heated and sintered to remove the binder in the semi-finished product of 3D printing powder 10. In the case of metal powder, a mixed gas of argon and hydrogen must be used in the sintering process for anti-oxidation protection. Finally, 3D printing powder 10 with a particle size of 10 μιη to 60 μιη is selected by sieving.

The 3D printing powder 10 that is finally formed has a particle size in the range of 10 - 60 μιη. In a preferred embodiment, the particle size of the 3D printing powder 10 is 20 - 40 μιη. Since the 3D printing powder 10 is formed by aggregation of powder base bodies 12, the 3D printing powder 10 will decompose into powder base bodies 12 with a particle size of 0.2 - 1 μιη when irradiated by a laser beam. The laser beam then sinters the powder base bodies 12, and can thereby give the surface of a component better roughness and precision. Furthermore, material remaining after printing is collected, and sieved again. Powder with a particle size in the range of 10 - 60 microns will be used again. Powder of a small size that was decomposed under the action of heat must again undergo granulation-^sintering-^sieving according to the flow described above, so as to obtain a powder meeting the particle size requirements .

Fig. 3 is a schematic diagram of a 3D printing apparatus which processes the 3D printing powder shown in Fig. 1. Referring to Fig. 3, the 3D printing apparatus 300 comprises a material supply unit 32, a forming unit 33 and a laser sintering unit 34. The material supply unit 32 supplies 3D printing powder to the forming unit 33. The laser sintering unit 34 is used to sinter the 3D printing powder 10, and cause the 3D printing powder 10 to form a required component on the forming unit 33.

Specifically, the material supply unit 32 comprises a supply piston 322, a first cylinder 323 and a roller wheel 324. The supply piston 322 is configured in the first cylinder 323 and can move up and down along the first cylinder 323. The 3D printing powder 10 is piled up on the supply piston 322. The roller wheel 324 can roll on the 3D printing powder 10, to spread the 3D printing powder 10 flat on the forming unit 33. Since the 3D printing powder 10 has a large particle size (10 microns to 60 microns) , the 3D printing powder 10 can be spread uniformly on the forming unit 33, and does not readily agglomerate or fly up.

The forming unit 33 comprises a forming piston 332, a second cylinder 333 and a forming part 334. The forming piston 332 is configured in the second cylinder 333, and can move up and down along the second cylinder 333. The forming part 334 is fixed on the forming piston 332, and can move up and down together with the forming piston 332. The forming part 334 is used to bear a component to be processed 301.

The laser sintering unit 34 comprises a laser 342 and a scanning lens 343. The laser 342 is connected to the scanning lens 343, and can generate a laser beam. The scanning lens 343 is used to sinter the 3D printing powder 10 into a preset structure using the laser beam provided by the laser 342. The 3D printing powder 10, under irradiation by the laser beam, is first of all decomposed into multiple powder base bodies 12. The laser beam heats the powder base bodies 12 further, i.e. can sinter the powder base bodies 12 into a preset structure.

It must be explained that the 3D printing apparatus 300 also comprises a controller (not shown in the figure) that is connected electrically to the material supply unit 32, the forming unit 33 and the laser sintering unit 34. The controller can control the actions of the material supply unit 32, the forming unit 33 and the laser sintering unit 34 according to a preset shape of the component, to finally produce the required component .

Fig. 4 is a flow chart of a method for 3D printing using the 3D printing powder shown in Fig. 1. Referring to Figs. 4 and 3, the 3D printing method of the present invention comprises the following steps:

Step S41: 3D printing powder 10 and a 3D printing apparatus 300 are provided; the 3D printing powder 10 has a particle size Dl in the range of 10 microns to 60 microns, each 3D printing powder 10 being formed by aggregation of multiple powder base bodies 12, the powder base bodies 12 having a particle size D2 in the range of 0.2 microns to 1 micron.

Step S42: the 3D printing powder 10 is spread on the forming part 334 of the 3D printing apparatus 300.

Step S43: a laser beam emitted by the 3D printing apparatus 300 is used to scan and irradiate the 3D printing powder 10 on the forming part 334.

Step S44: the 3D printing powder 10 is decomposed into powder base bodies 12; the laser beam continues to irradiate the powder base bodies 12 until the powder base bodies 12 are sintered into a preset shape.

Specifically, the 3D printing technology is for example selective laser melting technology. During actual operations, the roller wheel 324 first of all spreads a flat layer of 3D printing powder 10 on the forming part 334 of the forming unit 33. The laser sintering unit 34 controls a laser beam to scan and irradiate the 3D printing powder 10 so as to increase the temperature of the 3D printing powder 10. The 3D printing powder 10 is first decomposed into powder base bodies 12; the laser beam then heats the powder base bodies 12 to melting point, and sinters the powder base bodies 12 to form the component to be processed 301.

When sintering of one sectional layer is complete, the forming piston 332 will move down by a distance of one layer thickness, and the supply piston 322 will move up by a distance of one layer thickness. At this time, the roller wheel 324 will again spread a layer of 3D printing powder 10 uniformly on top of the component to be processed 301, and sintering of a new sectional layer will begin. Operations are repeated in this way until the component to be processed 301 is completely formed. In other words, once step S44 has been performed, steps S42 to S44 are performed again, and this cycle is repeated until the required component is formed.

It must be noted that since the component formed is formed by lamination during 3D printing, an interlayer structure can be eliminated by a suitable heat treatment process, to improve the mechanical properties of the material, in particular high- temperature creep resistance. The specific heat treatment process must be determined according to the printing material selected through corresponding orthogonal testing. The heat treatment process employed in the present invention is for example: homogenization for 0.5 - 2 hours at 1050 - 1080 degrees, air cooling to 730 - 790 degrees, maintaining this temperature for 5 - 20 hours, furnace cooling to 630 - 680 degrees and maintaining this temperature for 5 - 10 hours.

The 3D printing powder and 3D printing method of the present invention at least have the following advantages:

1. In the case of the 3D printing powder and 3D printing method of the present invention, the 3D printing powder has a large particle size and good flow properties, so can meet the requirements of a powder spreading process in selective laser melting technology. During powder spreading, the 3D printing powder does not readily aggregate or fly up. When the powder spreading process is complete, a laser beam irradiates the 3D printing powder, which can then decompose into powder base bodies of a smaller particle size, such that the component produced from the 3D printing powder of the present invention has a better surface finish and better mechanical properties.

3. In an embodiment of the 3D printing powder and 3D printing method of the present invention, when the 3D printing powder is sintered, it can first of all decompose into powder base bodies of a smaller size; when sintered by melting, the powder base bodies can fill gaps in the material, so that the component produced is more compact, and has better mechanical properties .

4. In an embodiment of the 3D printing powder and 3D printing method of the present invention, since the powder base bodies have a smaller particle size, a laser beam of lower power can melt the powder base bodies. Thus, the requirements on selective laser melting equipment are also lower, and this helps to reduce costs.

5. In an embodiment of the 3D printing powder and 3D printing method of the present invention, since a laser beam of lower power can melt the powder base bodies, and a lower irradiation temperature can cause the powder base bodies to melt completely, deformation of the component can be reduced.

6. In an embodiment of the 3D printing powder and 3D printing method of the present invention, since a reduction in size can realize a reduction in the temperature of sintering or powder melting, the use of existing additive manufacturing equipment to manufacture a ceramic component is made possible. In other words, existing additive manufacturing equipment can manufacture a ceramic-based product using the 3D printing powder of the present invention.

7. In an embodiment of the 3D printing powder and 3D printing method of the present invention, the 3D printing powder of the present invention is processed using 3D printing technology. A complex component can be processed in a single operation, with no need to first make the constituent parts of the component and then weld the constituent parts together, so the processing time can be shortened effectively.

The embodiments above are merely preferred embodiments of the present invention, which are not intended to limit it. Any amendments, equivalent substitutions or improvements etc. made within the spirit and principles of the present invention shall be included in the scope of protection thereof.