Apparatus and Method Based on Selective Laser Melting Technique for Preparing Functionally Gradient Material

Abstract

A selective laser melting technology-based apparatus for preparing a gradient material, comprising a laser scanning array lens, and a powder storer, a powder mixer, a powder scraping plate, and a working platform that are provided in sequence from top to bottom; the powder storer is provided with two or more partitions; a bottom portion of the powder storer is provided with an outlet; the powder mixer is provided under the powder storer and is a horizontally provided rotational mixer; the powder scraping plate is disposed under the powder mixer; the working platform is provided under the powder scraping plate; the laser scanning array lens is provided on the working platform. The present invention further relates to a method for preparing a gradient material, comprising powder storing, powder scraping, powder mixing, powder laying, and printing. The method can guarantee the two-phase powder ratio in each layer of powder not change.

Claims

1. An apparatus based on selective laser melting technique for preparing a functionally gradient material, comprising: a laser scanning array lens, and a powder storer, a powder mixer, a powder scraping plate, and a working platform that are disposed in sequence from top to bottom; the powder storer is provided with two or more partitions, which are used to contain different kinds of powder; the bottom of the powder storer is provided with an outlet, and the different kinds of powder are mixed at a gradient ratio after passing through the outlet; the powder mixer is disposed under the powder storer and is a rotational mixer arranged horizontally; the powder mixed at a gradient ratio remains in the gradient mixed state in the powder mixer; and the powder scraping plate is disposed under the powder mixer; the working platform is disposed under the powder scraping plate; the laser scanning array lens is disposed on the working platform.

2. The device according to claim 1, wherein the powder storer is in a cuboid shape; in a case of 2 kinds of powder, the cross section of the powder storer consists of two triangles reversed from each other; in a case of 3 kinds of powder, the cross section of the powder storer consists of three symmetrical triangles; and in a case of 4 kinds of powder, the cross section of the powder storer consists of four triangles combined together.

3. The device according to claim 1, wherein the outlet in the bottom of the powder storer is a rectangular outlet movable along the bottom of the powder storer, and the powder will fall from the powder storer into the powder mixer when the outlet is moved from one end of the powder storer to the other end of the powder storer.

4. The device according to claim 1, wherein the powder mixer is generally in a cylindrical shape and placed horizontally.

5. The device according to claim 1, wherein the powder scraping plate comprises a powder laying groove for holding the powder and a powder laying blade for powder laying.

6. The device according to claim 1, wherein the functionally gradient material is a material for metal additive manufacturing.

7. The device according to claim 6, wherein the functionally gradient material is an iron-based material, nickel-based material, or titanium-based material.

8. A method for preparing a functionally gradient material with an apparatus based on selective laser melting technique for preparing a functionally gradient material, comprising: a laser scanning array lens, and a powder storer, a powder mixer, a powder scraping plate, and a working platform that are disposed in sequence from top to bottom; the powder storer is provided with two or more partitions, which are used to contain different kinds of powder; the bottom of the powder storer is provided with an outlet, and the different kinds of powder are mixed at a gradient ratio after passing through the outlet; the powder mixer is disposed under the powder storer and is a rotational mixer arranged horizontally; the powder mixed at a gradient ratio remains in the gradient mixed state in the powder mixer; and the powder scraping plate is disposed under the powder mixer; the working platform is disposed under the powder scraping plate; the laser scanning array lens is disposed on the working platform, comprising: powder storage: placing different kinds of powder in corresponding partitions of the powder storer respectively; powder scraping: a movable rectangular outlet is provided in the bottom of the powder storer, the different kinds of powder falls from the powder storer at a preset ratio accordingly into the cylindrical powder mixer arranged horizontally when the movable rectangular outlet is moved from one end of the powder storer to the other end of the powder storer, and thereby form gradient powder; powder mixing: closing the powder mixer and driving it to rotate for mixing after the powder falls into the powder mixer, opening the powder mixer with the opening of the powder mixer facing downward after the mixing, so that the mixed powder falls into the powder scraping plate under a gravity action; powder laying: pushing the powder mixed at a gradient ratio with the powder scraping plate onto the working platform; printing: melting the layer of powder by scanning with a laser beam under the control of the laser scanning array lens after the powder is laid on the working platform; repeating powder scraping, powder mixing, powder laying, and printing steps, so as to prepare a part of functionally gradient material finally.

9. The method according to claim 8, wherein the gradient ratio of the gradient powder remains constant in the axial direction of the powder mixer in the powder mixing process.

10. The device according to claim 2, wherein the outlet in the bottom of the powder storer is a rectangular outlet movable along the bottom of the powder storer, and the powder will fall from the powder storer into the powder mixer when the outlet is moved from one end of the powder storer to the other end of the powder storer.

11. The device according to claim 2, wherein the powder mixer is generally in a cylindrical shape and placed horizontally.

12. The device according to claim 2, wherein the powder scraping plate comprises a powder laying groove for holding the powder and a powder laying blade for powder laying.

13. The method according to claim 8, wherein the powder storer is in a cuboid shape; in a case of 2 kinds of powder, the cross section of the powder storer consists of two triangles reversed from each other; in a case of 3 kinds of powder, the cross section of the powder storer consists of three symmetrical triangles; and in a case of 4 kinds of powder, the cross section of the powder storer consists of four triangles combined together.

14. The method according to claim 8, wherein the outlet in the bottom of the powder storer is a rectangular outlet movable along the bottom of the powder storer, and the powder will fall from the powder storer into the powder mixer when the outlet is moved from one end of the powder storer to the other end of the powder storer.

15. The method according to claim 8, wherein the powder mixer is generally in a cylindrical shape and placed horizontally.

16. The method according to claim 8, wherein the powder scraping plate comprises a powder laying groove for holding the powder and a powder laying blade for powder laying.

17. The method according to claim 8, wherein the functionally gradient material is a material for metal additive manufacturing.

18. The method according to claim 17, wherein the functionally gradient material is an iron-based material, nickel-based material, or titanium-based material.

19. The method according to claim 13, wherein the outlet in the bottom of the powder storer is a rectangular outlet movable along the bottom of the powder storer, and the powder will fall from the powder storer into the powder mixer when the outlet is moved from one end of the powder storer to the other end of the powder storer.

20. The method according to claim 13, wherein the powder mixer is generally in a cylindrical shape and placed horizontally.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings illustrate one or more embodiments of the present invention and, together with the written description, serve to explain the principles of the invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment.

[0029] FIG. 1 is a block diagram of the process flow of the method based on selective laser melting technique for preparing a functionally gradient material in an embodiment of the present invention;

[0030] FIG. 2 is a schematic structural diagram of the apparatus in the present invention, wherein FIG. 2a is a front sectional view, and FIG. 2b is a side sectional view;

[0031] FIG. 3 is a schematic diagram illustrating the cross-sectional shape of a powder storer containing 2 phases of powder;

[0032] FIG. 4 is a schematic diagram illustrating the cross-sectional shape of a powder storer containing 3 phases of powder;

[0033] FIG. 5 is a schematic diagram illustrating the cross-sectional shape of a powder storer containing 4 phases of powder;

[0034] In the Figures: 1powder storer; 2outlet; 3powder mixer; 4powder scraping plate; 5working platform; 6laser scanning array lens.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the present invention are shown. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure is thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.

[0036] Hereunder the embodiments of the present invention will be detailed with reference to the accompanying drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments shall not be deemed as separate ones; instead, they may be combined with each other to attain a better technical effect. In the accompanying drawings mentioned in the following embodiments, identical features or components are represented by the same symbols, and those symbols may be applied in different embodiments.

[0037] As shown in FIG. 2, an apparatus based on selective laser melting technique for preparing a functionally gradient material, comprising a laser scanning array lens 6, and a powder storer 1, a powder mixer 3, a powder scraping plate 4, and a working platform 5 that are disposed in sequence from top to bottom, wherein the powder storer 1 is provided with 2 or more partitions, which are used to contain different kinds of powder; the bottom of the powder storer 1 is provided with an outlet 2, and the different kinds of powder are mixed at a gradient ratio after passing through the outlet 2; the powder mixer 3 is disposed under the powder storer 1 and is a rotational mixer arranged horizontally; the powder mixed at a gradient ratio remains in the gradient mixed state in the powder mixer 3; the powder scraping plate 4 is disposed under the powder mixer 3; the working platform 4 is disposed under the powder scraping plate 5; the laser scanning array lens 6 is disposed on the working platform 5, and the working platform 5 can move up and down.

[0038] Preferably, the powder storer 1 is generally in a cuboid shape; in a case of 2 kinds of powder (two phases), the cross section of the powder storer 1 consists of two triangles reversed from each other, as shown in FIG. 3; in a case of 3 kinds of powder (three phases), the cross section of the powder storer 1 consists of three symmetrical triangles, as shown in FIG. 4; in a case of 4 kinds of powder (four phases), the cross section of the powder storer 1 consists of four triangles combined together, as shown in FIG. 5.

[0039] Preferably, the outlet 2 in the bottom of the powder storer 1 is a rectangular outlet movable along the bottom of the powder storer 1, and the powder will fall from the powder storer 1 into the powder mixer 3 when the outlet 2 is moved from one end of the powder storer 1 to the other end of the powder storer 1.

[0040] Preferably, the powder mixer 3 is generally in a cylindrical shape and placed horizontally.

[0041] Preferably, the powder scraping plate 4 comprises a powder laying groove for holding the powder and a powder laying blade for powder laying.

[0042] The functionally gradient material is a material for metal additive manufacturing, such as an iron-based material, nickel-based material, or titanium-based material.

[0043] As shown in FIG. 1, the method for preparing a functionally gradient material with the above-mentioned apparatus according to an embodiment of the present invention comprises:

[0044] powder storage: placing different kinds of powder in corresponding partitions of the powder storer 1 respectively; in a case that the powder consists of two phases, the partitions of the powder storer 1 are the partitions as shown in FIG. 3; in a case that the powder consists of three phases, the partitions are the partitions as shown in FIG. 4; in a case that the powder consists of four phases, the partitions are the partitions as shown in FIG. 5;

[0045] powder scraping: a movable rectangular outlet 2 is provided in the bottom of the powder storer 1, the different kinds of powder (2 kinds in this embodiment) falls from the powder storer 1 at a preset ratio accordingly into the cylindrical powder mixer 3 arranged horizontally when the movable rectangular outlet 2 is moved from one end of the powder storer 1 to the other end of the powder storer 1, and thereby form gradient powder;

[0046] powder mixing: closing the powder mixer 3 and driving it to rotate for mixing after the powder falls into the powder mixer 3, opening the powder mixer 3 with the opening of the powder mixer 3 facing downward after the mixing, so that the mixed powder falls into the powder laying groove of the powder scraping plate 4 under a gravity action; since the powder mixer 3 is disposed horizontally and can roll, the gradient powder can be mixed intensively and homogeneously in the powder mixer 3 and the gradient ratio of the gradient powder remains constant in the axial direction of the powder mixer 3 in the powder mixing process;

[0047] powder laying: after the working platform 5 is lowered by the height of one layer, scraping the powder of functionally gradient material onto the working platform 5 (the base plate of a working chamber) with the powder laying blade, so as to lay the powder of functionally gradient material;

[0048] printing: melting the layer of powder by scanning with a laser beam under the control of the laser scanning array lens 6 after the powder is laid on the working platform 5;

[0049] repeating the above powder scraping, powder mixing, powder laying, and printing steps, so as to prepare a part of functionally gradient material finally.

[0050] The traditional method for preparing functionally gradient materials only supports layer-by-layer powder replacement. Consequently, in the obtained final product, though the gradients of the layers are different from each other, it is unable to realize continuous gradient change. With the apparatus and method provided in the present invention, continuous transition in the functionally gradient material can be realized, and the gradient change direction of the functionally gradient material is changed from the part manufacturing direction extending vertically in traditional additive manufacturing to a horizontal direction perpendicular to the powder laying direction, and the mix ratio of the two-phase powder in each layer of powder doesn't vary as the height of the layer is increased through powder storage-powder mixing-powder laying procedures, and the stability of the powder layers are maintained.

[0051] While some embodiments of the present invention have been described above, those skilled in the art should appreciate that various modifications can be made to those embodiments without departing from the spirit of the present invention. Those embodiments are only exemplary, and shall not be deemed as constituting any limitation to the scope of protection of the present invention.