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 apparatuses are becoming widespread, and various techniques have been proposed for recoaters that spread powder on the powder bed of powder additive manufacturing apparatuses.

[0003] For example, U.S. Patent No. 5,393,633 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 is swept across at least a portion of the surface of the layer to form a layer of the 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. That is, the flowability of the powder varies due to the variation in particle size of the powder and the impurities and moisture contained in the powder. Therefore, the density of the powder supplied to the recoater becomes uneven. Therefore, when the powder is spread by the above-mentioned technique, the powder bed becomes uneven. When the powder bed has unevenness, there is a risk of reducing the accuracy of the product manufactured by the powder additive manufacturing apparatus.

[0006] The present disclosure has been made to solve such problems, and provides a recoater and a powder additive manufacturing apparatus that suppresses unevenness in 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 has 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 moving direction perpendicular to the main shaft and parallel to the surface. The powder guide unit 135 is provided around the main shaft at a preset inclination angle with respect to the moving direction. Effect of the Invention

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

[0009] [Figure 1] 1 is an overall view of a powder rapid prototyping apparatus according to an embodiment; [Diagram 2] FIG. 2 is a top view of a recoater according to the embodiment. [Diagram 3] FIG. 2 is a cross-sectional view of a recoater according to an embodiment of the present invention. [Figure 4] 5A to 5C are diagrams showing examples of the shape of a powder guide part according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0011] <Embodiment Mode> Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is an overall view of a powder additive manufacturing apparatus according to an embodiment. The powder additive manufacturing apparatus 1 shown in Fig. 1 is a type of so-called 3D printer, and produces a desired three-dimensional shape by forming and stacking thinly sliced ​​two-dimensional layers one by one based on three-dimensional design data. The powder additive manufacturing apparatus 1 mainly comprises a recoater 10, a main body block 20, a powder supplying device 30, and a laser oscillation device 40.

[0012] For convenience of explaining the positional relationship of the components, a right-handed Cartesian coordinate system is used in Fig. 1. Also, in Fig. 2 and subsequent figures, when a Cartesian coordinate system is used, the X-axis, Y-axis, and Z-axis directions in Fig. 1 coincide with the X-axis, Y-axis, and Z-axis directions in these Cartesian coordinate systems, respectively.

[0013] Fig. 1 is a side view of a powder rapid prototyping apparatus 1, with a portion shown in cross section for ease of explanation. In the powder rapid prototyping apparatus 1 shown in Fig. 1, a moving block 13 of a recoater 10 moves from one end, which is the right side (negative side of the Y axis), to the other end, which is the left side (positive side of the Y axis), thereby spreading powder 90 on a powder bed 91. That is, in the powder rapid prototyping apparatus 1, the right side of Fig. 1 is the initial position of the moving block 13, and by moving from this initial position to the left side, powder 90, which is the material of a manufactured product, is spread on the powder bed 91. After moving to the other end of the powder rapid prototyping apparatus 1 and spreading powder 90 on the powder bed 91, the moving block 13 returns to the initial position shown in the figure.

[0014] After the powder 90 is spread on the powder bed 91 as described above, the powder rapid prototyping apparatus 1 performs the following basic operations. That is, the laser oscillation device 40 melts the powder 90 at a desired position corresponding to the shape of the product. Next, the main body block 20 moves the powder bed 91 downward a preset distance. Furthermore, the powder supply device 30 supplies a predetermined amount of powder 90 to the recoater 10. Then, the recoater 10 spreads the supplied powder 90 on the powder bed 91 again. The powder rapid prototyping apparatus 1 repeats the above operations to manufacture a desired three-dimensional shape. The powder 90 in this embodiment is a powder mainly composed of metal or 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 "movement direction of the recoater 10." In the following description, the positive direction of the Y-axis may be referred to as the forward direction, and the negative direction of the Y-axis may be referred to as the backward direction. In the following description, the positive direction of the X-axis may be referred to as the rightward direction, the negative direction of the X-axis may be referred to as the leftward direction, the positive direction of the Z-axis may be referred to as the upward direction, and the negative direction of the Z-axis may be referred to as the downward direction.

[0016] The recoater 10 works in conjunction with the powder supplying device 30 and the main body block 20, and spreads the powder supplied from the powder supplying device 30 onto the powder bed support portion 21 of the main body block 20 to form a 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 driving motor 111, a feed shaft 112, and a bearing 113. The feed shaft driving motor 111 is a motor for rotating the feed shaft 112. The feed shaft 112 is supported at one end and the other end of the powder additive manufacturing apparatus 1 in parallel with the moving direction of the recoater 10, and is inserted into a 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 slidably engages with the feed shaft 112, so that the moving block 13 moves linearly from one end to the other end as the feed shaft 112 rotates.

[0018] With the above-mentioned 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 have a counter shaft (not shown). The counter shaft is disposed parallel to the feed shaft 112 and slidably engaged with the moving block 13, stabilizing the movement of the moving block 13 when it moves.

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

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

[0021] The powder supplying device 30 stores powder 90 and supplies the powder 90 to the powder receiving section 22 of the main body block 20 as appropriate. The powder supplying device 30 is installed so as to be movable up and down, and is configured to descend when supplying powder 90 to the main body block 20 and ascend when supply of powder 90 is completed so as not to interfere with the operation of the moving block 13. The powder supplying device 30 includes a powder supply port 31. The powder supply port 31 discharges the powder 90 stored in the powder supplying device 30 into the powder receiving section 22.

[0022] Laser oscillation device 40 is installed above powder bed support part 21, and irradiates laser light 41 at a desired position on powder bed 91 formed on the upper surface of powder bed support part 21. When laser oscillation device 40 irradiates powder bed 91 with laser light 41, a product 92 is formed on powder bed 91.

[0023] The above describes the main components of the powder additive manufacturing apparatus 1. In order to manufacture a desired three-dimensional shape, the powder additive manufacturing apparatus 1 thinly spreads powder 90, which is a material powder, on a powder bed. The powder additive manufacturing apparatus 1 then irradiates the thinly spread powder 90 with laser light 41 to melt it, and bonds and solidifies the molten material to form a slice-like shape. The powder additive manufacturing apparatus 1 manufactures the desired three-dimensional shape by repeatedly forming the 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 the recoater according to the 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 compacting roller 137, a roller drive motor 138, and a powder compacting plate 139. The moving block 13 shown in Fig. 2 moves in the positive direction of the Y axis (i.e., forward of the powder additive manufacturing apparatus 1) and conveys powder 90 supplied from the powder supplying device 30 to the powder bed 91.

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

[0026] The leveling plate 131 is a plate-like 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 moving direction, and is configured such that its main surface faces forward in the moving direction and one end is in contact with the surface of the powder bed in parallel. Note that the left and right ends of the leveling plate 131 may be bent or curved forward as shown in FIG. 2. This allows the leveling plate 131 to suppress the movement of the powder 90 that attempts to move to the outer area of ​​the powder bed 91 at the left and right ends.

[0027] The powder guiding 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 guiding block 132 has, as its main components, a main shaft 133, a conversion unit 134, a powder guiding unit 135, and a main shaft drive motor 136.

[0028] The main shaft 133 is supported rotatably in a direction parallel to the surface of the powder bed 91 and perpendicular to the moving direction (i.e., 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 moving direction perpendicular to the main shaft 133 and parallel to the surface of the powder bed 91.

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

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

[0031] The powder pressing roller 137 further smoothes the surface of the powder bed 91 after the powder guide block 132 has passed. The powder pressing roller 137 is a cylindrical member whose left and right ends are rotatably supported by the frame 130 behind the main shaft 133. The powder pressing roller 137 is disposed parallel to the main shaft 133 and contacts the surface of the powder bed 91 in parallel. One end of the powder pressing 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 pressing roller 137. As a result, the powder pressing roller 137 contacts the powder bed 91 while rotating when the moving block 13 moves forward.

[0032] The powder compaction plate 139 further smoothes 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 thereto.

[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 moves 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 arranged behind the leveling plate 131 has a tip portion along the circumference at a preset distance from the center of the main shaft 133. The tip portion of the powder guide unit 135 rotates and contacts the powder 90 to level the powder bed 91. In this embodiment, the main shaft 133 moves forward while rotating in the direction in which it rolls toward the moving direction. In the following description, this rotation direction is referred to as the forward direction. The conversion unit 134 is fixed around the main shaft 133. The conversion unit 134 is a cylindrical member, and the inner diameter portion fits with the main shaft 133, and the outer diameter portion holds the powder guide unit 135. That is, the powder guide unit 135 is fixed to the outer periphery of the conversion unit 134.

[0036] The powder pressing roller 137 disposed behind the powder guide block 132 moves while further smoothing the surface of the powder bed 91. In this embodiment, the powder pressing roller 137 moves while rotating in a rolling direction opposite to the moving direction. In the following description, this rotating direction is referred to as the reverse direction.

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

[0038] Next, examples of the shape of powder guiding section 135 of 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 section according to an embodiment. Fig. 4 is a top view of conversion section 134 and powder guiding section 135. Conversion section 134 shown in Fig. 4 has, from left to right, first conversion section 134A, second conversion section 134B, third conversion section 134C, fourth conversion section 134D, fifth conversion section 134E and sixth conversion section 134F 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 each fixed to the main shaft 133, they operate integrally with the main shaft 133. Since the conversion unit 134 is configured in multiple regions, the recoater 10 can easily replace the conversion unit 134 and the powder guide unit 135 held by the conversion unit 134. Therefore, the recoater 10 in this embodiment is configured to facilitate setting changes and maintenance.

[0040] Each of the first conversion unit 134A to the fifth conversion unit 134E has one or more powder guiding units 135. The powder guiding units 135 are provided around the main shaft 133, each at a preset inclination angle with respect to the movement direction.

[0041] The first conversion unit 134A has, for example, a first powder guiding unit 135A. The first powder guiding unit 135A is formed to form a first inclination angle A11 with respect to the moving direction. The first powder guiding unit 135A is formed in such a direction that the portion that contacts 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. That is, the first powder guiding 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 moving direction.

[0042] The second conversion section 134B has, for example, a second powder guiding section 135B. The second powder guiding section 135B is formed to form a second inclination angle A12 smaller than the above-mentioned first inclination angle A11 with respect to the moving direction. The second powder guiding section 135B is formed in a direction in which a portion that contacts 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. That is, the second powder guiding section 135B is configured to move the powder 90 in the area of ​​the second conversion section 134B from the inside to the outside in the left-right direction while moving the powder bed 91 in the moving direction.

[0043] The third conversion section 134C has, for example, two third powder guide sections 135C. The two third powder guide sections 135C are formed parallel to each other so as to form a third inclination angle A13 smaller than the above-mentioned second inclination angle A12 with respect to the moving direction. The third powder guide section 135C is formed in a direction such that a portion that contacts 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. That is, the third powder guide section 135C is configured to move the powder 90 in the area of ​​the third conversion section 134C from the inside to the outside in the left-right direction while moving the powder bed 91 in the moving direction.

[0044] With the above-mentioned configuration, powder guiding unit 135 moves in the movement direction along the surface of powder bed 91 in the area where it is installed, and moves powder 90 in the left-right direction in the area where it comes into contact. The amount of powder 90 moved by powder guiding unit 135 is set by the movement speed of moving block 13, the rotation speed of main shaft 133, and the angle between powder guiding unit 135 and the movement direction. In other words, the powder guiding unit 135 moves a relatively larger amount of powder 90 when the movement speed of moving block 13 is relatively slower. Also, the powder guiding unit 135 moves a relatively larger amount of powder 90 when the rotation speed of main shaft 133 is relatively faster.

[0045] In addition, at this time, the relative distance in the left-right direction over which powder guiding part 135 moves powder 90 is set according to the angle it forms with the movement direction. More specifically, the distance over which powder guiding part 135 moves powder 90 in the left-right direction is relatively longer as the angle it forms with the movement direction is relatively larger.

[0046] In the above example, the first powder guiding section 135A having the first inclination angle A11, which is the largest angle with respect to the moving direction, moves the powder 90 in the left-right direction longer than the second powder guiding section 135B and the third powder guiding section 135C. The second powder guiding section 135B having the second inclination angle A12, which is smaller than the first inclination angle A11 and larger than the third inclination angle A13, moves the powder 90 in the left-right direction shorter than the first powder guiding section 135A, and moves the powder 90 in the left-right direction longer than the third powder guiding section 135C. The third powder guiding section 135C having the third inclination angle A13, which is the smallest angle with respect to the moving direction, moves the powder 90 in the left-right direction shorter than the first powder guiding section 135A and the second powder guiding section 135B.

[0047] In addition, the main shaft 133 in this embodiment has a first powder guide portion 135A having a first inclination angle A11 at the end side in the axial direction, and a second powder guide portion 135B having a second inclination angle A12 smaller than the first inclination angle A11 at the center side from the end side. With this configuration, the recoater 10 moves the powder 90 at the left and right ends of the powder bed 91 a relatively long distance toward the center in the left and right direction, and moves the powder 90 at the center in the left and right direction of the powder bed 91 a relatively short distance toward the left and right ends. With the above-mentioned configuration, the recoater 10 can dynamically smooth out unevenness that occurs after the powder 90 supplied from the powder supplying device 30 is leveled by the leveling plate 131.

[0048] An example of the configuration of powder guiding section 135 in powder guiding block 132 has been described above. As described above, powder guiding section 135 is provided around main shaft 133 along a preset inclination angle with respect to the direction of movement. However, various aspects of powder guiding section 135 can be adopted. For example, powder guiding section 135 may be formed around main shaft 133 in parallel adjacent to each other, as in third powder guiding section 135C in the above example. Powder guiding section 135 may also be formed in a spiral shape around main shaft 133, as in fourth powder guiding section 135D.

[0049] Furthermore, powder guide block 132 may be configured such that main shaft 133 and conversion portion 134 are integrally formed, for example. In this case, main shaft 133 has a plurality of powder guide portions 135. The inclination angles of each powder guide portion 135 may be the same or different from each other. Main shaft 133 may be set such that a plurality of regions are connected along the axial direction, and each region may have a powder guide portion 135 with a different shape.

[0050] Although the embodiment has been described above, the recoater 10 according to the embodiment is not limited to the above-mentioned configuration. For example, the recoater 10 may be removed from the above-mentioned configuration when the powder pressing roller 137 or the powder pressing plate 139 is not required. The rotation direction of the powder guide block 132 may be set to the forward direction as described above, or may be set to the reverse direction. The powder supplying device 30 constituting the powder additive manufacturing apparatus 1 is not limited to the above-mentioned configuration, and may be included in the main body block 20 and may be configured to push up a predetermined amount of powder 90 onto 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 moving block 13 when returning to the initial position after spreading the powder 90 on the powder bed 91. The recoater 10 may have a mechanism that allows the moving block 13 to move upward once 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 embodiment, 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 without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0053] 1 Powder additive manufacturing equipment 10 Recoater 11 Moving mechanism 13 Moving Blocks 20 Body block 21 Powder bed support 22 Powder receiving section 30 Powder feeding device 31 Powder supply port 40 Laser Oscillation Device 41 Laser light 90 powder 91 Powder bed 92 Manufactured products 111 Feed shaft drive motor 112 Feed shaft 113 Bearings 130 frames 131 Leveling board 132 Powder Induction Block 133 Main axis 134 Conversion Unit 135 Powder induction part 136 Spindle drive motor 137 Powder Roller 138 Roller drive motor 139 Powder Plate 140 Powder surface

Claims

1. a spindle rotating about an axis parallel to the surface of the powder bed; A plurality of cylindrical conversion parts that are fitted to the main shaft and connected together along the axial direction of the main shaft; a powder guide portion provided around the conversion portion and having a predetermined inclination angle with respect to the axial direction, Spreading powder onto the powder bed; Additive manufacturing methods.

2. Further comprising a step of setting a combination of a plurality of the conversion units to set the amount of the powder moved by the powder guide unit. The additive manufacturing method according to claim 1 .

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