Additive manufacturing method

Abstract

To provide a re-coater that suppresses unevenness of powder spread on a powder bed, and a powder additive manufacturing apparatus.SOLUTION: There is provided a re-coater 10 that supplies a predetermined amount of powder, and spreads supplied powder across a powder bed. The re-coater 10 includes a main shaft 133, a moving mechanism 11, and a powder guiding part 135. The main shaft 133 rotates about an axis parallel to a surface of the powder bed. The moving mechanism 11 is perpendicular to the main shaft and moves the main shaft in a moving direction parallel to the surface of the powder bed. The powder guiding part 135 is disposed around the main shaft along a predetermined inclination angle relative to the moving direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a recoater and a powder additive manufacturing apparatus. [Background technology]

[0002] Powder additive manufacturing (PM) devices are becoming increasingly popular, and various technologies have been proposed for recoaters that spread powder on the powder bed of the PM additive manufacturing device.

[0003] For example, U.S. Patent No. 5,949,999 discloses a means for forming a layer of material adjacent to an already formed cross section of an object, the means comprising a counter-rotating roller that sweeps across at least a portion of the surface of the layer to form a layer of a desired thickness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-513130 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when spreading powder on a powder bed, the following problem occurs. Specifically, the fluidity of the powder varies due to variations in the particle size of the powder and impurities and moisture contained in the powder. This causes variations in the density of the powder supplied to the recoater. Therefore, when powder is spread using the above-mentioned technique, variations in the powder bed occur. If variations in the powder bed occur, there is a risk of a decrease in the accuracy of the products manufactured by the powder rapid prototyping device.

[0006] The present disclosure has been made to solve such problems, and provides a recoater and a powder additive manufacturing apparatus that suppresses unevenness of the powder spread on the powder bed. [Means for solving the problem]

[0007] The recoater 10 according to the present disclosure supplies a preset amount of powder and spreads the powder on a powder bed. The recoater 10 includes a main shaft 133, a moving mechanism 11, and a powder guide unit 135. The main shaft 133 rotates about an axis parallel to the surface of the powder bed. The moving mechanism 11 moves the main shaft in a direction perpendicular to the main shaft and parallel to the surface. The powder guide unit 135 is disposed around the main shaft at a preset inclination angle relative to the moving direction. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a recoater and a powder rapid prototyping apparatus that suppresses unevenness of the powder spread on the powder bed. [Brief explanation of the drawings]

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

[0010] The present invention will be described below through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential means for solving the problems. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are assigned the same reference numerals, and duplicate explanations are omitted as necessary.

[0011] <Embodiment> Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall view of a powder bed additive manufacturing apparatus according to the embodiment. The powder bed additive manufacturing apparatus 1 shown in FIG. 1 is a kind of so-called 3D printer, which manufactures a desired three-dimensional shape by forming and laminating thin two-dimensional layers one by one based on three-dimensional design data. The main components of the powder bed additive manufacturing apparatus 1 include a recoater 10, a main body block 20, a powder supply device 30, and a laser oscillator 40.

[0012] For the sake of convenience in explaining the positional relationship of the components, FIG. 1 is provided with a right-handed orthogonal coordinate system. Also, in FIGS. 2 and later, when an orthogonal coordinate system is provided, the X-axis, Y-axis, and Z-axis directions in FIG. 1 coincide with the X-axis, Y-axis, and Z-axis directions of these orthogonal coordinate systems, respectively.

[0013] FIG. 1 is a side view of the powder bed additive manufacturing apparatus 1, and a part is shown as a cross section for convenience of explanation. In the powder bed additive manufacturing apparatus 1 shown in FIG. 1, the moving block 13 of the recoater 10 moves from the right side (Y-axis minus side), which is one end, to the left side (Y-axis plus side), which is the other end, to spread the powder 90 over the powder bed 91. That is, in the powder bed additive manufacturing apparatus 1, the right side of the moving block 13 in FIG. 1 is the initial position, and by moving from this initial position to the left side, the powder 90 that becomes the material of the manufactured product is spread over the powder bed 91. When the moving block 13 moves to the other end of the powder bed additive manufacturing apparatus 1 to spread the powder 90 over the powder bed 91, it returns to the initial position shown in the figure.

[0014] Note that when the powder bed 91 is spread with the powder 90 as described above, the powder bed forming apparatus 1 performs the following operations as basic operations. That is, the laser oscillation device 40 melts the powder 90 at a desired position corresponding to the shape of the manufactured product. Next, the main body block 20 moves the powder bed 91 downward by a preset distance. Further, the powder supply device 30 supplies a predetermined amount of the powder 90 to the recoater 10. Then, the recoater 10 spreads the supplied powder 90 again on the powder bed 91. The powder bed forming apparatus 1 repeats the above operations to manufacture a desired three-dimensional shape. Note that the powder 90 in the present embodiment is a powder mainly composed of a metal or a resin that is melted by laser light.

[0015] In the following description, the direction parallel to the Y-axis may be referred to as the "moving direction of the recoater 10". Also, in the following description, the plus direction of the Y-axis may be referred to as the front, and the minus direction of the Y-axis may be referred to as the rear. Also, in the following description, the plus direction of the X-axis may be referred to as the right direction, the minus direction of the X-axis may be referred to as the left direction, the plus direction of the Z-axis may be referred to as the upward direction, and the minus direction of the Z-axis may be referred to as the downward direction.

[0016] The recoater 10 operates in conjunction with the powder supply device 30 and the main body block 20, spreads the powder supplied from the powder supply device 30 on the powder bed support portion 21 of the main body block 20, and forms the powder bed 91. The recoater 10 mainly includes a moving mechanism 11 and a moving block 13.

[0017] The moving mechanism 11 includes a feed shaft drive motor 111, a feed shaft 112, and a bearing 113. The feed shaft drive motor 111 is a motor for rotating the feed shaft 112. The feed shaft 112 is supported in parallel with the moving direction of the recoater 10 at one end and the other end of the powder bed forming apparatus 1 and is inserted through the bearing 113. The feed shaft 112 has a spiral guide groove, and a convex portion of the bearing 113 slidably engages with the guide groove. The bearing 113 is connected to the moving block 13 and is slidably engaged with the feed shaft 112. When the feed shaft 112 rotates, the moving block 13 is configured to linearly move from one end to the other end.

[0018] With the above-described configuration, the moving mechanism 11 moves the moving block 13 from one end to the other end by the feed shaft drive motor 111 rotating the feed shaft 112. The moving mechanism 11 may also have a counter shaft (not shown). The counter shaft is arranged parallel to the feed shaft 112 and slidably engages with the moving block 13, stabilizing the movement of the moving block 13 as it moves.

[0019] The main body block 20 includes a housing that supports the powder rapid prototyping apparatus 1 on a resting surface. The main body block 20 also supports the recoater 10 at its upper part. The main body block 20 includes a powder bed support section 21 and a powder receiving section 22 as its main components.

[0020] The powder bed support part 21 is engaged with a rectangular hole provided in the upper surface of the main body block 20 so as to be movable up and down. The powder bed support part 21 has a flat upper surface, which supports a powder bed 91. The powder receiving part 22 is a flat surface provided between the powder bed support part 21 and the moving block 13, and receives powder 90 supplied from the powder supply device 30.

[0021] Powder supplying device 30 stores powder 90 and supplies powder 90 to powder receiving section 22 of main body block 20 as needed. Powder supplying device 30 is installed so as to be movable up and down, descending when supplying powder 90 to main body block 20 and ascending when supplying powder 90 is complete so as not to interfere with the operation of moving block 13. Powder supplying device 30 includes powder supply port 31. Powder supply port 31 discharges powder 90 stored in powder supplying device 30 into powder receiving section 22.

[0022] The laser oscillator 40 is installed above the powder bed support portion 21, and irradiates a desired position with a laser beam 41 onto a powder bed 91 formed on the upper surface of the powder bed support portion 21. When the laser oscillator 40 irradiates the powder bed 91 with the laser beam 41, a product 92 is formed on the powder bed 91.

[0023] The above has described the main components of the powder rapid prototyping apparatus 1. In order to manufacture a desired three-dimensional shape, the powder rapid prototyping apparatus 1 spreads a thin layer of powder 90, which is a material powder, on a powder bed. The powder rapid prototyping apparatus 1 then irradiates the thinly spread powder 90 with laser light 41 to melt it, and forms a slice-like shape by bonding and solidifying the molten material. The powder rapid prototyping apparatus 1 manufactures the desired three-dimensional shape by repeatedly forming these slice-like shapes and sequentially stacking them.

[0024] Next, the moving block 13 will be described in detail with reference to Fig. 2. Fig. 2 is a top view of a recoater according to an embodiment. The moving block 13 shown in Fig. 2 is a top view of the moving block 13. The moving block 13 mainly comprises a frame 130, a leveling plate 131, a powder guide block 132, a powder compaction roller 137, a roller drive motor 138, and a powder compaction plate 139. Fig. 2 shows the moving block 13 moving in the positive direction of the Y axis (i.e., toward the front of the powder rapid prototyping apparatus 1) and transporting powder 90 supplied from the powder supplying device 30 to the powder bed 91.

[0025] The frame 130 is a structure that supports each component of the moving block 13, and supports the left and right ends of the leveling plate 131, the powder guide block 132, the powder compaction roller 137, the roller drive motor 138, and the powder compaction plate 139. The frame 130 is also connected to the bearing 113 shown in FIG.

[0026] The leveling plate 131 is a plate-shaped member that moves the powder 90 supplied from the powder supplying device 30 to the powder bed 91 while leveling the surface of the powder bed 91. The leveling plate 131 is disposed in front of the main shaft 133 in the direction of movement, with its main surface facing forward in the direction of movement and one end configured to be in contact with and parallel to the surface of the powder bed. Note that, as shown in FIG. 2, the left and right ends of the leveling plate 131 may be bent or curved forward. This allows the left and right ends of the leveling plate 131 to suppress the movement of the powder 90 that attempts to move to areas outside the powder bed 91.

[0027] The powder guide block 132 further smoothes the powder 90 on the surface of the powder bed 91 after it has been leveled by the leveling plate 131. The powder guide block 132 mainly comprises a spindle 133, a conversion unit 134, a powder guide unit 135, and a spindle drive motor 136.

[0028] The main shaft 133 is supported so as to be rotatable in a direction parallel to the surface of the powder bed 91 and perpendicular to the movement direction (i.e., a direction parallel to the X-axis). One end of the main shaft 133 is connected to a main shaft drive motor 136. As a result, when the moving block 13 moves forward, the main shaft 133 comes into contact with the powder bed 91 while rotating. In other words, the moving mechanism 11 moves the main shaft 133 in a movement direction perpendicular to the main shaft 133 and parallel to the surface of the powder bed 91.

[0029] The conversion units 134 are multiple cylindrical members connected together along the axial direction (X-axis direction) around the main shaft 133 and inside the powder guide units 135. The conversion units 134 are fitted to the main shaft 133 at their inner diameter portions, and rotate in conjunction with the main shaft 133. The conversion units 134 also hold the powder guide units 135 at their outer diameter portions.

[0030] Powder guide portion 135 is a convex member fixed to the periphery of main shaft 133 or conversion portion 134. Powder guide block 132 in this embodiment has multiple powder guide portions 135. Powder guide portions 135 are fixed to the outer periphery of conversion portion 134 at a preset inclination angle with respect to the direction of movement.

[0031] The powder compacting roller 137 further smooths the surface of the powder bed 91 after the powder guide block 132 has passed. The powder compacting roller 137 is a cylindrical member rotatably supported at its left and right ends on the frame 130 behind the main shaft 133. The powder compacting roller 137 is disposed parallel to the main shaft 133 and comes into contact with the surface of the powder bed 91 in a parallel manner. One end of the powder compacting roller 137 is connected to a roller drive motor 138. The roller drive motor 138 is fixed to the frame 130 and drives the powder compacting roller 137. As a result, the powder compacting roller 137 comes into contact with the powder bed 91 while rotating as the moving block 13 moves forward.

[0032] The powder compaction plate 139 further smooths the surface of the powder bed 91 after the powder compaction roller 137 has passed. The powder compaction plate 139 is disposed behind the main shaft 133 in the direction of movement, more specifically behind the powder compaction roller 137. The powder compaction plate 139 has a powder compaction surface that contacts the surface of the powder bed 91 in parallel.

[0033] The moving block 13 will be further described with reference to Fig. 3. Fig. 3 is a cross-sectional view of the recoater according to the embodiment. Fig. 3 shows the moving block 13 at the cross section III-III shown in Fig. 2. Fig. 3 also shows a state in which the moving block 13 has moved forward from the state shown in Fig. 2 and is moving on the surface of the powder bed 91.

[0034] 3, the leveling plate 131 is moving forward while leveling the powder 90. The main surface of the leveling plate 131 faces the direction of movement of the moving block 13, and the lower end is in contact with the surface of the powder bed 91 in parallel.

[0035] The powder guide unit 135, located behind the leveling plate 131, has a tip that runs along the circumference at a preset distance from the center of the main shaft 133. The tip of the powder guide unit 135 rotates and comes into contact with the powder 90 to level the powder bed 91. In this embodiment, the main shaft 133 moves forward while rotating in a rolling direction toward the direction of movement. In the following description, this rotation direction will be referred to as the forward direction. A conversion unit 134 is fixed to the periphery of the main shaft 133. The conversion unit 134 is a cylindrical member whose inner diameter portion fits into the main shaft 133 and whose outer diameter portion holds the powder guide unit 135. In other words, the powder guide unit 135 is fixed to the outer periphery of the conversion unit 134.

[0036] The powder compacting roller 137, located behind the powder guide block 132, moves while further smoothing the surface of the powder bed 91. In this embodiment, the powder compacting roller 137 moves while rotating in a rolling direction opposite to the direction of movement. In the following description, this rotation direction will be referred to as the "reverse direction."

[0037] A powder compaction plate 139, disposed behind the powder compaction roller 137, has a powder compaction surface 140 that contacts and is parallel to the surface of the powder bed 91. The front and rear ends of the powder compaction surface 140 each have a guided shape, which allows the powder compaction plate 139 to further smooth the powder bed 91.

[0038] Next, examples of the shape of the powder guiding portion 135 of the powder guiding block 132 will be described with reference to Fig. 4. Fig. 4 is a diagram showing examples of the shape of the powder guiding portion according to an embodiment. Fig. 4 is a top view of the conversion portion 134 and the powder guiding portion 135. The conversion portion 134 shown in Fig. 4 is made up of, from left to right, a first conversion portion 134A, a second conversion portion 134B, a third conversion portion 134C, a fourth conversion portion 134D, a fifth conversion portion 134E, and a sixth conversion portion 134F, which are connected together.

[0039] The first to fifth conversion units 134A to 134E are each detachably fixed to the main shaft 133. However, when the first to fifth conversion units 134A to 134E are fixed to the main shaft 133, they operate integrally with the main shaft 133. By configuring the conversion unit 134 in multiple regions, the recoater 10 can easily replace the conversion units 134 and the powder guide units 135 held by the conversion units 134. Therefore, the recoater 10 in this embodiment is configured to facilitate setting changes and maintenance.

[0040] Each of the first to fifth conversion units 134A to 134E has one or more powder guide units 135. The powder guide units 135 are provided around the main shaft 133 at a predetermined inclination angle relative to the movement direction.

[0041] The first conversion unit 134A has, for example, a first powder guide unit 135A. The first powder guide unit 135A is formed to form a first inclination angle A11 with respect to the direction of movement. The first powder guide unit 135A is formed in a direction such that the portion that comes into contact with the powder bed 91 moves from the outside to the inside of the main shaft 133 when the main shaft 133 rotates in the forward direction. In other words, the first powder guide unit 135A is configured to move the powder 90 in the area of the first conversion unit 134A from the outside to the inside in the left-right direction while moving on the surface of the powder bed 91 in the movement direction.

[0042] The second conversion unit 134B has, for example, a second powder guide unit 135B. The second powder guide unit 135B is formed to form a second inclination angle A12, which is smaller than the first inclination angle A11, with respect to the direction of movement. The second powder guide unit 135B is also formed in a direction such that the portion that comes into contact with the powder bed 91 moves from the inside to the outside of the main shaft 133 when the main shaft 133 rotates in the forward direction. In other words, the second powder guide unit 135B is configured to move the powder 90 in the area of the second conversion unit 134B from the inside to the outside in the left-right direction while moving the powder bed 91 in the movement direction.

[0043] The third conversion unit 134C has, for example, two third powder guide units 135C. The two third powder guide units 135C are formed parallel to each other and form a third inclination angle A13, which is smaller than the second inclination angle A12, with respect to the direction of movement. The third powder guide units 135C are formed in such a direction that the portion that comes into contact with the powder bed 91 moves from the inside to the outside of the main shaft 133 when the main shaft 133 rotates in the forward direction. In other words, the third powder guide unit 135C is configured to move the powder 90 in the area of the third conversion unit 134C from the inside to the outside in the left-right direction while moving the powder bed 91 in the movement direction.

[0044] With the above configuration, the powder guiding unit 135 moves along the moving direction along the surface of the powder bed 91 in the installed area, and moves the powder 90 in the contacting area in the left - right direction. The amount of powder 90 that the powder guiding unit 135 moves is set by the moving speed of the moving block 13, the rotational speed of the main shaft 133, and the angle formed by the powder guiding unit 135 with the moving direction. That is, the slower the moving speed of the moving block 13, the more powder 90 the powder guiding unit 135 moves. Also, the faster the rotational speed of the main shaft 133, the more powder 90 the powder guiding unit 135 moves.

[0045] Also at this time, the relative distance in the left - right direction for the powder guiding unit 135 to move the powder 90 is set according to the angle formed with the moving direction. More specifically, the larger the angle formed by the powder guiding unit 135 with the moving direction, the longer the distance for the powder guiding unit 135 to move the powder 90 in the left - right direction.

[0046] In the case of the above example, the first powder guiding unit 135A having the first inclination angle A11 with the largest angle formed with the moving direction moves the powder 90 a longer distance in the left - right direction than the second powder guiding unit 135B and the third powder guiding unit 135C. The second powder guiding unit 135B having the second inclination angle A12 smaller than the first inclination angle A11 and larger than the third inclination angle A13 moves the powder 90 a shorter distance in the left - right direction than the first powder guiding unit 135A and a longer distance than the third powder guiding unit 135C. The third powder guiding unit 135C having the third inclination angle A13 with the relatively smallest angle formed with the moving direction moves the powder 90 a shorter distance in the left - right direction than the first powder guiding unit 135A and the second powder guiding unit 135B.

[0047] In addition, the main shaft 133 in the present embodiment has a first powder guiding portion 135A having a first inclination and a first inclination angle A11 on the end side in the axial direction, and a second powder guiding portion 135B having a second inclination and a second inclination angle A12 smaller than the first inclination angle A11 on the central side rather than the end side. With such a configuration, the recoater 10 moves the powder 90 at the left and right ends of the powder bed 91 to the central side in the left-right direction over a relatively long distance, and moves the powder 90 at the central portion in the left-right direction of the powder bed 91 to the left and right end sides over a relatively short distance. The recoater 10 can dynamically adjust the unevenness generated after the powder 90 supplied from the powder supply device 30 is leveled by the leveling plate 131 by the above-described configuration.

[0048] As described above, an example of the configuration of the powder guiding portion 135 in the powder guiding block 132 has been described. As described above, the powder guiding portion 135 is provided along a preset inclination angle with respect to the moving direction around the main shaft 133. However, the powder guiding portion 135 can adopt various modes. For example, the powder guiding portion 135 may be formed around the main shaft 133 with a plurality of powder guiding portions 135 adjacent to each other in parallel, like the third powder guiding portion 135C in the above example. Further, the powder guiding portion 135 may be formed in a spiral shape around the main shaft 133 as exemplified by the fourth powder guiding portion 135D.

[0049] In addition, the powder guiding block 132 may be configured such that, for example, the main shaft 133 and the conversion portion 134 are integrated. In that case, the main shaft 133 has a plurality of powder guiding portions 135. The inclination angles of the respective powder guiding portions 135 may be the same or different from each other. The main shaft 133 may be set such that a plurality of regions are connected along the axial direction, and may have powder guiding portions 135 having different shapes for each region.

[0050] Although the embodiment has been described above, the recoater 10 according to the embodiment is not limited to the above-described configuration. For example, the recoater 10 may be configured without the powder compaction roller 137 or the powder compaction plate 139 if they are not required. The rotation direction of the powder guide block 132 may be set to the forward direction as described above, or the reverse direction. The powder supplying device 30 constituting the powder rapid prototyping apparatus 1 is not limited to the above-described configuration. For example, it may be configured to be included inside the main body block 20 and push a predetermined amount of powder 90 up to the upper surface of the main body block 20. The main body block 20 may have a mechanism that allows the recoater 10 to move downward and separate from the movable block 13 when returning to the initial position after spreading the powder 90 on the powder bed 91. The recoater 10 may also have a mechanism that allows the movable block 13 to move upward and separate from the upper surface of the main body block 20 when returning to the initial position after spreading the powder 90 on the powder bed 91.

[0051] As described above, according to the embodiments, it is possible to provide a recoater and a powder rapid prototyping apparatus that suppresses unevenness of the powder spread on the powder bed.

[0052] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention. [Explanation of symbols]

[0053] 1 Powder additive manufacturing equipment 10 Recoater 11 Moving mechanism 13 Moving Blocks 20 Main body block 21 Powder bed support 22 Powder receiving section 30 Powder feeding device 31 Powder supply port 40 Laser Oscillator 41 Laser light 90 powder 91 Powder bed 92 Manufactured products 111 Feed axis drive motor 112 Feed shaft 113 Bearings 130 frame 131 leveling plate 132 powder induction block 133 main shaft 134 conversion part 135 powder induction part 136 main shaft drive motor 137 compacting roller 138 roller drive motor 139 compacting plate 140 compacting surface

Claims

【Claim 1】 a main shaft that rotates about an axis parallel to the surface of the powder bed, a plurality of cylindrical conversion parts fitted to the main shaft and connected along the axial direction of the main shaft, using a recoater comprising at least a powder guiding part provided around the conversion part and having a predetermined inclination angle with respect to the axial direction, having a step of spreading powder on the powder bed, further having a step of setting a combination of a plurality of the conversion parts in order to set the amount of the powder moved by the powder guiding part, a layered manufacturing method.

Images