JP7746819B2 - Recoater device and additive manufacturing device - Google Patents

Description

This disclosure relates to a recoater apparatus and an additive manufacturing apparatus.

Layered manufacturing devices that manufacture objects by solidifying a powder material are known (see, for example, Patent Documents 1 and 2). Such layered manufacturing devices include, for example, a table that supports a powder bed containing powder, an irradiation device that irradiates the powder bed on the table with an energy beam, and a recoater device that smooths the surface of the powder bed. The recoater device has a recoater that includes a contact surface that contacts the surface of the powder bed, and a recoater movement mechanism that moves the recoater horizontally over the surface of the powder bed. Examples of recoaters that can be used include metal recoaters and soft recoaters made of rubber, silicone, or the like.

Japanese Patent Application Laid-Open No. 2019-127651 Japanese Patent Application Laid-Open No. 2018-122479

However, when a metal recoater is used, the pressing force from the recoater is likely to deform the model as it moves across the surface of the powder bed. On the other hand, when a soft recoater such as rubber or silicone is used, the surface of the recoater is likely to be scratched when pressed against the model, and is also likely to be susceptible to the adhesion of spatter generated during energy beam irradiation. If the surface shape of the recoater is deformed due to the formation of such scratches or the adhesion of spatter, the shape corresponding to the recoater surface may be reflected in the model when the recoater performs its coating operation. Therefore, with the above-mentioned recoaters, the model may be formed into an unintended shape, raising concerns about a reduction in the quality of the model.

This disclosure describes a recoater device and an additive manufacturing device that can suppress deterioration in the quality of the molded object.

A recoater apparatus according to one embodiment of the present disclosure includes a holder that moves the recoater relative to the surface in a first direction along the main surface, and the recoater includes a tip surface that extends along the main surface and in a second direction that intersects the first direction, a core material made of a material that elastically deforms upon receiving a reaction force from an object to be formed on the main surface, and a cover layer that covers at least the tip surface and is positioned so as to face the surface, and is made of a material harder than the core material.

In the above-described recoater device, the core material of the recoater is made of an elastic material that elastically deforms when subjected to a reaction force from the object. Therefore, when the recoater comes into contact with the object while moving over the surface of the powder bed, it can overcome the object without deforming it. Furthermore, the tip surface of the core material is covered with a cover layer that is harder than the core material. This hard cover layer is less susceptible to deformation of the surface shape due to scratches and spatter adhesion. Therefore, by arranging the cover layer in a position facing the surface of the powder bed, deformation of the contact surface of the recoater (i.e., the outer surface of the cover layer) due to scratches or spatter adhesion can be prevented. This prevents the surface shape of the recoater from being reflected in the object during the recoater coating operation. Therefore, the above-described recoater device prevents the object from being formed in an unintended shape, thereby preventing a decrease in the quality of the object.

In some embodiments, the cover layer may be a metal plate made of a metal material. Metal plates have relatively high hardness and heat resistance. This prevents spatter from embedding in and adhering to the metal plate when it is pressed against the metal plate at a high temperature. Therefore, the above configuration more reliably prevents the cover layer from being damaged by scratches or deformation of the surface shape due to the adhesion of spatter.

In some embodiments, the cover layer may have enough rigidity to deform when subjected to a reaction force from the molded object. In this case, the cover layer can deform together with the core material when subjected to a reaction force from the molded object, thereby reducing the pressing force applied to the molded object by the recoater compared to when the cover layer does not deform. This more reliably prevents deformation of the molded object as the recoater moves. Furthermore, the cover layer can return to its original shape as the core material elastically deforms, allowing for stable coating operations by the recoater.

In some embodiments, the recoater may further have a pair of side surfaces aligned in the first direction, and the cover layer may have a tip surface cover portion that covers the tip surface and a pair of side surface cover portions that extend from the tip surface and cover the pair of side surfaces. In this case, the cover layer can be easily attached to the core material by the simple task of wrapping and fixing the cover layer along the shape of the core material.

In some embodiments, the cover layer may have a plurality of slits that are spaced apart in the second direction and extend from the tip surface cover portion to the pair of side surface cover portions. In this case, the portions of the cover layer between the plurality of slits are each independently deformable. Therefore, when the recoater receives a reaction force from the molded object in the first direction, only the portion of the cover layer that receives the reaction force can be deformed in the first direction. In this case, the pressing force applied to the molded object by the recoater can be more effectively reduced compared to when the entire cover layer deforms in the first direction, thereby more reliably preventing deformation of the molded object due to movement of the recoater.

In some embodiments, the cover layer may be removably attached to the core material. In this case, even if the cover layer is damaged, it is not necessary to replace the entire recoater, and only the cover layer needs to be replaced, thereby improving maintainability.

In some embodiments, the cover layer has an outer surface facing away from the tip surface, and the outer surface may be curved so as to bulge toward the surface when viewed from the second direction. In this case, it is possible to prevent the recoater from getting caught on the molded object as it moves over the surface of the powder bed. As a result, it is possible to more reliably prevent deformation of the molded object as the recoater moves.

An additive manufacturing apparatus according to one embodiment of the present disclosure includes a chamber, a table disposed within the chamber and supporting a powder bed containing powder, an irradiation device that irradiates the powder on the table with an energy beam, and any of the recoater devices described above that are disposed within the chamber and level the surface of the powder bed.

The above-mentioned additive manufacturing device includes any of the recoater devices described above. Therefore, the above-mentioned additive manufacturing device can prevent the object from being formed in an unintended shape, thereby preventing a decrease in the quality of the object.

According to some aspects of the present disclosure, a recoater apparatus and an additive manufacturing apparatus are provided that can suppress deterioration in the quality of the molded object.

FIG. 1 is a cross-sectional view showing an additive manufacturing apparatus according to an embodiment. FIG. 2 is a perspective view showing a recoater device provided in the layered manufacturing apparatus of FIG. FIG. 3 is a side view showing the recoater device. FIG. 4 is a cross-sectional view showing a recoater device. FIG. 5 is an exploded perspective view showing a recoater provided in the recoater device. Fig. 6(a) is a perspective view showing the metal plate of the recoater, and Fig. 6(b) is a plan view showing the metal plate of Fig. 6(a) in an expanded state. FIG. 7 is an enlarged plan view of the portion P in FIG. 6(b). 8A is a cross-sectional view showing the recoater climbing over the protruding portion of the model, and FIG. 8B is a cross-sectional view showing the recoater after climbing over the protruding portion of the model. 9A is a side view showing a recoater apparatus according to Comparative Example 1. FIG. 9B is a side view showing a recoater apparatus according to Comparative Example 2. 10A is a side view showing a recoater apparatus according to Comparative Example 3. FIG. 10B is a side view showing a recoater apparatus according to Comparative Example 4.

Embodiments of the present disclosure will be described below with reference to the drawings. Note that in the description of the drawings, identical elements will be assigned the same reference numerals, and duplicate explanations will be omitted.

The additive manufacturing device shown in Figure 1 is a so-called 3D (three-dimensional) printer. In the following description, the additive manufacturing device will be simply referred to as "modeling device 1." The modeling device 1 partially applies energy to powder 2 arranged in layers, sintering or melting the powder 2. The modeling device 1 repeatedly sinters or melts the powder 2 to manufacture a three-dimensional model 3.

The molded object 3 is, for example, a mechanical part. The molded object 3 may also be other structures. The material of the powder 2 is, for example, a metal. The powder 2 may be, for example, a metal powder such as titanium-based metal powder, Inconel (registered trademark) powder, aluminum powder, or stainless steel powder. The material of the powder 2 is not limited to metal, and may be other materials such as ceramic or resin. The powder 2 may contain carbon fiber and resin, such as CFRP (Carbon Fiber Reinforced Plastics), or may contain other materials. For example, the powder 2 may contain a conductive material that is electrically conductive.

The modeling apparatus 1 includes a vacuum chamber 4 (chamber), a table 5, an elevator device 6, a powder supply device 7, an irradiation device 8, a modeling tank 10, and a controller 18. The vacuum chamber 4 is a container capable of creating a vacuum (low pressure) inside. A vacuum pump is connected to the vacuum chamber 4. The vacuum chamber 4 houses the table 5, the elevator device 6, the powder supply device 7, and the modeling tank 10. The table 5 is disposed within the vacuum chamber 4 and within the modeling tank 10. The table 5 has, for example, a plate shape. In a plan view, the shape of the table 5 is, for example, circular. The shape of the table 5 is not limited to circular and may be other shapes such as rectangular.

A substrate 15 is placed on the table 5. Powder 2, which is the material for the object 3, is placed on the substrate 15. Therefore, the table 5 supports the powder 2 and the object 3 via the substrate 15. The powder 2 on the substrate 15 is placed, for example, in layers, in multiple batches. The table 5 is movable in the Z direction within the modeling tank 10. The table 5 then descends sequentially according to the number of layers of powder 2. The side wall 10a of the modeling tank 10 guides the movement of the table 5. The shape of the side wall 10a corresponds to the outer shape of the table 5. For example, when the table 5 is a disk, the shape of the area surrounded by the side wall 10a is cylindrical. The side wall 10a of the modeling tank 10 and the table 5 form a storage section that stores the powder 2 and the object 3. The table 5 may also form the bottom of the modeling tank 10.

The lifting device 6 raises and lowers the table 5. As the lifting device 6 raises and lowers the table 5, the substrate 15 on the table 5, the powder 2 on the substrate 15, and the molded object 3 rise and fall. The lifting device 6 includes, for example, a rack-and-pinion drive mechanism. These mechanisms allow the lifting device 6 to move the table 5 in the Z direction. The Z direction may be a direction perpendicular to the table, for example, a direction along the vertical direction. In the following description, the terms "upper" and "lower" are used based on the state in which the Z direction is aligned with the vertical direction. The term "lower" refers to the lower side in the vertical direction, and the term "upper" refers to the upper side in the vertical direction.

The lifting device 6 includes a vertical member 6a (rack) and a drive source 6b. The vertical member 6a is a rod-shaped member that is connected to the underside of the table 5 and extends downward. The drive source 6b drives the vertical member 6a. An electric motor, for example, is used as the drive source 6b. A pinion is provided on the output shaft of the electric motor. Teeth that mesh with the pinion are provided on the side of the vertical member 6a. When the electric motor is driven, the pinion rotates. This pinion rotation transmits power, causing the vertical member 6a to move vertically. When the electric motor stops rotating, the vertical member 6a is positioned. As a result, the position of the table 5 in the Z direction is determined, and the position of the table 5 is maintained. The lifting device 6 is not limited to a rack-and-pinion drive mechanism. For example, the lifting device 6 may include other drive mechanisms, such as a ball screw or cylinder.

The powder supply device 7 includes a pair of raw material tanks 11. The pair of raw material tanks 11 are storage units for storing the raw material powder 2. The pair of raw material tanks 11 are located above the table 5 within the vacuum chamber 4. The pair of raw material tanks 11 are located, for example, on both sides of the electron beam irradiation area D of the irradiation device 8 in the X direction (first direction) intersecting the Z direction. A discharge port is provided at the bottom of each raw material tank 11. The discharge port of each raw material tank 11 is continuous, for example, in the Y direction (second direction). The Y direction is a direction intersecting the X and Z directions. The X and Y directions may be directions along the main surface 5a of the table 5, or may be directions along the horizontal direction, for example. A protruding plate 12 is provided below each raw material tank 11 and extends laterally from the upper end of the side wall 10a of the modeling tank 10. The protruding plate 12 forms a plane along the X and Y directions around the table 5.

The powder supply device 7 includes a recoater device 20, which is a powder application mechanism that levels the powder 2. The recoater device 20 is positioned above the table 5 and the extension plate 12 and is movable in the X direction. By moving in the X direction, the recoater device 20 scrapes the powder 2 deposited on the extension plate 12 onto the table 5. Furthermore, by moving in the X direction, the recoater device 20 levels the surface 2a (top surface) of the top layer of the stack of powder 2 on the table 5. Hereinafter, the "stack of powder 2" will be referred to as powder bed A. The recoater device 20 moves in the X direction while abutting against the surface 2a of powder bed A, thereby leveling the height of the surface 2a. The recoater device 20 may include, for example, a rack-and-pinion drive mechanism. The recoater device 20 may include a guide rail, an endless belt, a ball screw, an electric motor, a cylinder, or the like as a drive mechanism.

The irradiation device 8 is, for example, an electron beam irradiation device including an electron gun that irradiates an electron beam (electron beam) as an energy beam. In Figure 1, the irradiation area D through which the emitted electron beam passes is indicated by a two-dot chain line. The electron beam emitted from the electron gun is irradiated into the vacuum chamber 4. The electron beam heats the powder 2. In other words, the irradiation device 8 imparts energy to the powder 2. As a result, the powder 2 is heated and melts or sinters. The irradiation device 8 is a powder solidification unit that solidifies the powder 2 in the powder bed A. The irradiation device 8 can also be said to be an energy imparting unit that imparts energy to the powder bed A.

The irradiation device 8 may include a coil device that controls the irradiation of the electron beam. The coil device may include, for example, an aberration coil, a focus coil, and a deflection coil. The aberration coil is placed around the electron beam emitted from the electron gun and focuses the electron beam. The focus coil is placed around the electron beam emitted from the electron gun and corrects deviations in the focus position of the electron beam. The deflection coil is placed around the electron beam emitted from the electron gun and adjusts the irradiation position of the electron beam. The deflection coil performs electromagnetic beam deflection. Electromagnetic beam deflection allows for a faster scanning speed during electron beam irradiation than mechanical beam deflection. The electron gun and coil unit are located above the vacuum chamber 4. The electron beam emitted from the electron gun is converged, the focus position is corrected, and the scanning speed is controlled by the coil unit until it reaches the irradiation position of the powder 2.

The controller 18 is a control unit that controls the overall operation of the modeling apparatus 1. The controller 18 is a computer that includes hardware such as a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), as well as software such as programs stored in the ROM. The controller 18 includes an input signal circuit, an output signal circuit, a power supply circuit, etc. The controller 18 includes a calculation unit and memory. The controller 18 is electrically connected to the irradiation device 8, the powder supply device 7, and the lifting device 6. The controller 18 can generate various command signals. The memory can store data required for various controls.

The controller 18 sends command signals to the irradiation device 8 to control the timing and position of electron beam irradiation (irradiation control). The controller 18 controls the irradiation of the electron beam when melting the powder 2. The controller 18 can send command signals to the powder supply device 7 to control the timing and amount of powder 2 supply. The controller 18 may also send command signals to the recoater device 20 to control the operation timing of the recoater 21, etc.

Next, the configuration of the recoater apparatus 20 will be described in more detail. As shown in Figures 2 and 3, the recoater apparatus 20 includes a recoater 21 and a recoater moving mechanism 22. The recoater 21 is plate-shaped and extends in the Y direction. The recoater moving mechanism 22 is positioned adjacent to the recoater 21 in the X direction and holds the recoater 21. Like the recoater 21, the recoater moving mechanism 22 also extends in the Y direction. The length of the recoater moving mechanism 22 in the Y direction is, for example, longer than the length of the recoater 21 in the Y direction. The length of the recoater 21 in the Y direction corresponds, for example, to the overall length of the table 5 (see Figure 1) in the Y direction. The recoater moving mechanism 22 moves in the X direction relative to the surface 2a of the powder bed A while holding the recoater 21.

The recoater 21 has a core material 31 and a metal plate 41 (cover layer) that covers the core material 31. The core material 31 is a plate-shaped member with its longitudinal direction in the Y direction and its transverse direction in the Z direction. The plate thickness of the recoater 21 in the X direction is, for example, approximately 10 mm. As shown in FIG. 3 , the recoater 21 is disposed so as to stand on the surface 2a of the powder bed A. The core material 31 is made of a heat-resistant and elastic material such as rubber or silicone. The core material 31 made of such a flexible material has a lower Young's modulus than the molded object 3 formed by solidifying metal powder. Therefore, when the core material 31 is pressed against the molded object 3 while moving in the X direction, it easily deforms due to the reaction force from the molded object 3. This deformation of the core material 31 reduces the pressing force applied by the recoater 21 to the molded object 3.

As shown in Figures 3 and 4, the core material 31 has a tip surface 32 and a pair of side surfaces 33, 34 extending in a direction intersecting the tip surface 32. The tip surface 32 is the lower surface located at the lower end of the core material 31 in the Z direction, and extends continuously along the Y direction. When the recoater 21 is placed on the surface 2a of the powder bed A, the tip surface 32 faces the surface 2a in the Z direction via the metal plate 41. "The tip surface 32 facing the surface 2a in the Z direction" means that the normal to the tip surface 32 and the normal to the surface 2a include a Z-direction component and are arranged so as to intersect each other.

When viewed from the Y direction, the tip surface 32 has, for example, an arc shape that curves downward toward the surface 2a. The shape of the tip surface 32 when viewed from the Y direction is not limited to an arc shape and may be another shape, such as an ellipse. The tip surface 32 may be, for example, a flat surface along the XY plane. The pair of side surfaces 33, 34 are located at both ends of the core material 31 in the X direction and extend upward from the tip surface 32. Each of the pair of side surfaces 33, 34 is, for example, a flat surface extending along the YZ plane. The side surface 33 is located in a position facing the recoater movement mechanism 22 in the X direction. The side surface 34 is located on the opposite side of the recoater movement mechanism 22 in the X direction.

The metal plate 41 is a thin plate made of a metal material such as stainless steel, iron, or aluminum. Therefore, the metal plate 41 has a higher hardness than the core material 31. For example, the metal plate 41 may have a higher hardness than the solidified object 3. The higher the hardness of the metal plate 41, the less likely the surface shape of the metal plate 41 will deform, and the higher its resistance to scratches and other damage. "Hardness" is expressed by the magnitude of the resistance force generated when the surface of the material is pressed, and can be measured using various known hardness tests (e.g., Vickers hardness test, etc.). The hardness of the metal plate 41 can be determined using the measured values obtained from such hardness tests or their equivalent values.

On the other hand, the metal plate 41 has a certain degree of flexibility. Specifically, the metal plate 41 has enough rigidity to be deformed by the reaction force received from the object 3 while the recoater 21 is moving. Therefore, when the metal plate 41 receives a reaction force in the X direction from the object 3, the reaction force causes the metal plate 41 to deform in the X direction. Because the metal plate 41 has such rigidity, the metal plate 41 is bent in the X direction together with the core material 31 in response to the reaction force from the object 3. As a result, the pressing force from the recoater 21 to the object 3 is reduced, allowing the recoater 21 to overcome the object 3 without deforming it. Furthermore, the flexibility of the metal plate 41 improves the ease of assembling the metal plate 41 to the core material 31. In this embodiment, stainless steel is used as the material for the metal plate 41, which combines hardness and flexibility. Furthermore, in this embodiment, the thickness of the metal plate 41 is set to be sufficiently thin, taking flexibility into consideration. The thickness of the metal plate 41 is sufficiently smaller than the thickness of the core material 31, for example, in the range of 0.05 mm to 0.1 mm.

The metal plate 41 is arranged to cover at least the tip surface 32 of the core material 31. In this embodiment, the metal plate 41 is arranged to cover from the tip surface 32 to the pair of side surfaces 33, 34. As a result, the metal plate 41 has a U-shaped bent shape when viewed from the X direction. The metal plate 41 has a tip surface cover portion 42 that covers the tip surface 32, and a pair of side surface cover portions 43, 44 that cover the pair of side surfaces 33, 34. The tip surface cover portion 42 includes an outer surface 42a facing the surface 2a of the powder bed A, and an inner surface 42b facing the tip surface 32 of the core material 31. When viewed from the X direction, the outer surface 42a and the inner surface 42b have an arc-like shape that curves downward to follow the shape of the tip surface 32.

The inner surface 42b of the tip surface cover portion 42 may be in contact with the tip surface 32 without any gap, or may be disposed with a gap from the tip surface 32. The outer surface 42a of the tip surface cover portion 42 faces the surface 2a of the powder bed A in the Z direction. The outer surface 42a facing the surface 2a in the Z direction means that the normal to the outer surface 42a and the normal to the surface 2a include a Z-direction component and are disposed so that they intersect each other. Specifically, when the recoater 21 is disposed on the surface 2a of the powder bed A, the outer surface 42a abuts against the surface 2a in the Z direction. As the recoater 21 moves over the surface 2a while the outer surface 42a abuts against the surface 2a, the surface 2a is smoothed flat. The outer surface 42a is configured as the abutment surface S1 of the recoater 21 with respect to the surface 2a.

The side cover portion 43 extends from the tip surface cover portion 42 and is arranged to cover the side surface 33 of the core material 31. The side cover portion 43, for example, covers the entire surface of the side surface 33. The side cover portion 43, for example, is in contact with the side surface 33 of the core material 31 and the recoater movement mechanism 22 without any gaps. The side cover portion 43 is sandwiched between the side surface 33 of the core material 31 and the recoater movement mechanism 22. The side cover portion 44 extends from the tip surface cover portion 42 and is arranged to cover the side surface 34 of the core material 31. In this embodiment, the side cover portion 44 covers, for example, a portion of the side surface 34 excluding the upper end portion, but may also cover the entire surface of the side surface 34. The side cover portion 44, for example, is in contact with the side surface 34 of the core material 31 without any gaps.

As shown in Figures 2 to 4, the recoater moving mechanism 22 has a recoater device unit 51 (holder) that holds the recoater 21. The recoater device unit 51 includes a rectangular plate-shaped base 52 extending in the Y direction and a pair of walls 53, 54 extending downward from the lower end of the base 52. The base 52 includes a lower surface 52a located at the lower end of the base 52 in the Z direction and a pair of side surfaces 52b, 52c extending upward from the lower surface 52a. As shown in Figure 4, the lower surface 52a is a plane that faces the surface 2a of the powder bed A in the Z direction and is located above the tip surface cover unit 42. The lower surface 52a is located, for example, at the center of the recoater 21 in the Z direction or above that center. The pair of side surfaces 52b, 52c are planes perpendicular to the lower surface 52a and are located at both ends of the base 52 in the X direction. Therefore, the pair of side surfaces 52b, 52c are aligned in the X direction. Side surface 52b is positioned facing the side surface cover portion 43 in the X direction. Side surface 52c is positioned on the opposite side of the recoater 21 in the X direction.

The pair of walls 53, 54 protrude downward from both ends of the lower surface 52a in the Y direction. The pair of walls 53, 54 are, for example, rectangular plates along the XZ plane. The pair of walls 53, 54 are located outside the recoater 21 in the Y direction. Therefore, the distance between the pair of walls 53, 54 in the Y direction is wider than the width of the recoater 21 in the Y direction. As described above, the lower surface 52a of the base 52 is located at the center of the recoater 21 in the Z direction or above this center. Therefore, when the recoater 21 receives a reaction force in the X direction from the model 3, it can deform in the X direction without interfering with the recoater device unit 51. In other words, the recoater 21 is permitted to deform in the X direction in the space V (see Figure 4) enclosed by the pair of walls 53, 54 and the lower surface 52a of the base 52.

The recoater 21 is removably attached to the recoater device unit 51, for example, by a fastening member 70 (see Figure 2). The fastening member 70 includes, for example, two fixing bolts 71 and one fixing plate 72. The two fixing bolts 71 are inserted in the X direction through the base 52 of the recoater device unit 51 and the recoater 21 at positions spaced apart in the Y direction. The base 52 has two insertion holes 55 (see Figure 4), through which the two fixing bolts 71 are inserted, respectively. As shown in Figures 4 and 5, the core material 31 of the recoater 21 also has two insertion holes 35, through which the two fixing bolts 71 are inserted, respectively.

As shown in FIG. 5, four insertion holes 45 are formed in the metal plate 41 of the recoater 21. One fixing bolt 71 is inserted into two of the insertion holes 45, and the other fixing bolt 71 is inserted into the other two insertion holes 45. As shown in FIGS. 3 and 4, the head 71a of each fixing bolt 71 is positioned on the side surface 52c of the base 52, and the tip (thread tip) of each fixing bolt 71 protrudes in the X direction from the side cover portion 44 of the recoater 21. A fixing plate 72 is screwed onto the tip of each fixing bolt 71 protruding from the side cover portion 44. This fixes the recoater device portion 51, metal plate 41, and core material 31 to one another.

When attaching the recoater 21 to the recoater device unit 51, first, as shown in FIG. 5, the metal plate 41 is bent into a U-shape and attached so that it is wrapped around the core material 31. Then, as shown in FIGS. 3 and 4, two fixing bolts 71 are inserted from the base 52 of the recoater device unit 51 through the core material 31 and metal plate 41. The tip of each fixing bolt 71 protruding from the metal plate 41 is then threaded into the fixing plate 72, thereby sandwiching the base 52, core material 31, and metal plate 41 in the X direction between the head 71a of each fixing bolt 71 and the fixing plate 72. This secures the recoater device unit 51, core material 31, and metal plate 41 to one another. Furthermore, the recoater device unit 51, core material 31, and metal plate 41 can be removed from one another by loosening the fixing bolts 71. In this way, the recoater unit 51, core material 31, and metal plate 41 are removably attached to each other.

As shown in Figures 6(a) and 6(b), multiple slits 47 are formed in the metal plate 41. Figure 6(a) shows the metal plate 41 bent into a U-shape, while Figure 6(b) shows the metal plate 41 unfolded into a flat state. As shown in Figure 6(b), the unfolded metal plate 41 has a rectangular shape with direction D1 as the longitudinal direction and direction D2 as the lateral direction. Direction D1 coincides with the Y direction. Direction D2 may be a direction including the X direction or the Z direction. Each slit 47 is formed in the center of direction D2 of the metal plate 41. Each slit 47 extends linearly along direction D2 and is aligned at equal intervals along direction D1. Each slit 47 has, for example, the same dimensions and shape as one another.

Figure 7 shows an enlarged view of portion P in Figure 6(b). As shown in Figure 7, each slit 47 is formed continuously from the tip surface cover portion 42 to the pair of side surface cover portions 43, 44. Each slit 47 extends linearly in direction D2 from the side surface cover portion 43 through the tip surface cover portion 42 to a position where it reaches the side surface cover portion 44. The width of each slit 47 in direction D1 is set as small as possible from the perspective of ensuring the area of the metal plate 41. The width of each slit 47 in direction D1 is smaller than the arrangement pitch of each slit 47 in direction D1. The arrangement pitch of each slit 47 in direction D1 is, for example, approximately 1 mm.

The metal plate 41 has multiple divided portions P1 divided in direction D1 by the formation of multiple slits 47. Because the divided portions P1 are separated from one another in direction D1 at the formation positions of the slits 47, they can deform independently of one another when subjected to external forces. Therefore, when a divided portion P1 deforms due to an external force, the other divided portions P1 that are not subjected to the external force either do not deform or deform less than the divided portion P1. As shown in FIG. 2, when the recoater 21 is held by the recoater device unit 51, each slit 47 and each divided portion P1 is located below the lower surface 52a of the recoater device unit 51. Therefore, when any of the multiple divided portions P1 receives a reaction force in the X direction from the object 3, the divided portion P1 that receives the reaction force is bent and deformed in the X direction in the space V (see FIG. 4) below the lower surface 52a. In this embodiment, each slit 47 is configured as a gap with a width in direction D1, but it may also be configured as a notch with no width in direction D1. In this case, each divided portion P1 contacts each other in direction D1.

In the recoater device 20 described above, the recoater 21 held by the recoater movement mechanism 22 moves horizontally over the powder bed A in the X direction. As the recoater 21 moves, the contact surface S1 of the recoater 21 moves over the surface 2a of the powder bed A while making contact with the surface 2a. This makes the surface 2a of the powder bed A flat and level. The irradiation device 8 irradiates the powder 2 with an electron beam in accordance with the shape of one layer of the object 3. The powder 2 irradiated with the electron beam is melted or sintered, thereby forming the shape of one layer of the object 3. Thereafter, the recoater 21 moves horizontally over the surface 2a of the powder bed A again, depositing a new layer of powder 2 on top of the formed object 3. This operation is repeated to obtain the final object 3.

As shown in FIG. 8(a), when the recoater 21 moves in the X direction over the surface 2a of the powder bed A, it may receive a reaction force in the X direction from the protruding portion P3 of the model 3. The protruding portion P3 may be, for example, a portion of one layer of the model 3 that is thicker than other portions. In this embodiment, the core material 31 of the recoater 21 is made of a flexible material such as rubber or silicone. Therefore, the recoater 21 easily deforms when subjected to the reaction force from the protruding portion P3. Furthermore, the metal plate 41 covering the core material 31 has enough rigidity to deform when subjected to the reaction force from the protruding portion P3, and includes multiple divided portions P1 separated by multiple slits 47.

Therefore, when a reaction force from the protruding portion P3 is applied to the multiple divided portions P1 of the metal plate 41, one or more divided portions P1 to which the reaction force is applied are bent in the X direction together with the core material 31. On the other hand, the other divided portions P1 to which the reaction force is not applied are not deformed or are deformed less than the divided portions P1 to which the reaction force is applied. As a result, when the recoater 21 receives a reaction force from the protruding portion P3 of the shaped object 3, it is bent in the X direction at the location where the reaction force is applied and moves over the protruding portion P3. Then, as shown in FIG. 8(b), the recoater 21 returns to its original shape after moving over the protruding portion P3. In other words, the core material 31 elastically returns, and the metal plate 41 also returns to its original shape in response to this return movement of the core material 31.

Next, we will explain the effects achieved by the recoater device 20 and modeling device 1 according to this embodiment, along with the issues faced by the comparative example.

Figure 9(a) shows a recoater apparatus 120 according to Comparative Example 1. The recoater apparatus 120 differs from the recoater apparatus 20 according to this embodiment in that it includes a metal recoater 121. The recoater 121 is entirely made of metal and has high rigidity. Therefore, when the recoater 121 held by the recoater movement mechanism 122 moves in the X direction over the powder bed A and the model 3 is pressed against the recoater 121, a large pressing force is applied from the recoater 121 to the model 3. As a result, the model 3 may be significantly deformed as the recoater 121 moves. Therefore, with the recoater apparatus 120, the model 3 may be deformed into an unintended shape, which may result in a deterioration in the quality of the model 3.

Figure 9(b) shows a recoater apparatus 220 according to Comparative Example 2. The recoater apparatus 220 differs from the recoater apparatus 20 according to this embodiment in that it is equipped with a recoater 221 having a silicone blade 221a. Because the blade 221a is flexible, when the recoater 221 receives a reaction force from the model 3 as it moves in the X direction over the surface 2a of the powder bed A, the blade 221a easily deforms in the X direction. When the blade 221a deforms in this way, the pressing force applied from the blade 221a to the model 3 is reduced, thereby preventing the model 3 from deforming significantly as the recoater 221 moves.

However, if the blade 221a is made of such a soft material, the surface of the blade 221a is easily scratched when the blade 221a is pressed against the object 3. Furthermore, with such a material, spatter generated when the powder 2 is irradiated with the electron beam is likely to adhere to the surface of the blade 221a. Spatter is a large-diameter clump of powder 2 that does not completely melt into the object 3 and scatters. When such spatter, which is a clump of metal, is pressed against the blade 221a, the spatter is likely to become embedded in the surface of the blade 221a. If such scratches or spatter adhesion occur on the contact surface S221 of the blade 221a with the surface 2a of the powder bed A (i.e., the surface of the blade 221a that contacts the surface 2a of the powder bed A), unevenness is formed on the contact surface S221, and the object 3 may also have a shape corresponding to the contact surface S221.

For example, if the contact surface S221 of the blade 221a is scratched upon contact with the object 3, a groove may be formed on the contact surface S221, and a protrusion corresponding to the groove may be formed on the object 3. Furthermore, if spatter adheres to the contact surface S221 of the blade 221a, a protrusion may be formed on the contact surface S221, and a groove corresponding to the protrusion may be formed on the object 3. As a result, the object 3 may be formed into an unintended shape. Therefore, in the recoater device 220, there is a risk of a decrease in the quality of the object 3. Note that when forming the shape of one layer of the object 3, spatter may remain on the shape of that layer. In this state, when powder 2 for the next layer of the object 3 is supplied and the recoater 221 moves over that powder 2, the remaining spatter may adhere to the contact surface S221 of the blade 221a. Alternatively, spatter scattered when the powder 2 is irradiated with the electron beam may adhere directly to the contact surface S221 of the blade 221a.

Figure 10(a) shows a recoater apparatus 320 according to Comparative Example 3. The recoater apparatus 320 differs from the recoater apparatus 20 according to this embodiment in that it includes a recoater 321 having a rubber tube 321a. Like the blade 221a, the tube 321a is flexible, and therefore scratches or spatter adhesion are likely to occur on the contact surface S321 of the tube 321a. Therefore, even with the recoater apparatus 320, the molded object 3 may be formed into an unintended shape, which may result in a decrease in the quality of the molded object 3. Figure 10(b) shows a recoater apparatus 420 according to Comparative Example 4. The recoater apparatus 420 differs from the recoater apparatus 20 according to this embodiment in that it includes a brush recoater 421. However, with the brush recoater 421, unintended scattering of powder 2 is likely to occur when the brush recoater 421 moves over the powder bed A. Therefore, in the recoater device 420, variations in the flatness of the surface 2a of the powder bed A are likely to occur, and the quality of the molded object 3 is likely to deteriorate.

In the recoater apparatus 20 according to this embodiment, the core material 31 of the recoater 21 is made of an elastic material that elastically deforms when subjected to a force acting in the X direction, for example. Therefore, when the recoater 21 abuts against the protruding portion P3 of the object 3 while moving over the surface 2a of the powder bed A, it receives a reaction force in the X direction from the protruding portion P3, thereby elastically deforming and overcoming the protruding portion P3, allowing it to overcome the object 3 without deforming it. Furthermore, the tip surface 32 of the core material 31 is covered with a hard metal plate 41. Such a hard metal plate 41 is less susceptible to deformation of its surface shape due to scratches and spatter deposition. Therefore, by positioning the metal plate 41 facing the surface 2a of the powder bed A, it is possible to prevent the shape of the contact surface S1 of the recoater 21 (i.e., the outer surface 42a of the metal plate 41) abutting the surface 2a from becoming uneven due to scratches or spatter deposition. This prevents the object 3 from taking on a shape corresponding to the surface shape of the recoater 21 when the recoater 21 performs its coating operation. Therefore, the recoater device 20 according to this embodiment prevents the object 3 from being formed in an unintended shape, thereby preventing a decrease in the quality of the object 3.

In this embodiment, a metal plate 41 covers the core material 31 of the recoater 21. The metal plate 41 has a relatively high hardness and is heat resistant. Therefore, when high-temperature spatter is pressed against the metal plate 41, it is possible to prevent the spatter from becoming embedded in and adhering to the metal plate 41.

In this embodiment, the metal plate 41 has enough rigidity to deform when it receives a reaction force, for example in the X direction, from the protruding portion P3 of the object 3. In this case, the metal plate 41 can deform in the X direction together with the core material 31 when it receives a reaction force from the protruding portion P3 of the object 3. Therefore, the pressing force applied by the recoater 21 to the object 3 can be reduced compared to when the metal plate 41 does not deform. This more reliably prevents deformation of the object 3 as the recoater 21 moves. Furthermore, the metal plate 41 can also return to its original shape as the core material 31 elastically deforms, allowing the recoater 21 to perform a stable coating operation.

In this embodiment, the metal plate 41 has a tip surface cover portion 42 that covers the tip surface 32, and a pair of side surface cover portions 43, 44 that extend from the tip surface 32 and cover a pair of side surfaces. In this case, the metal plate 41 can be easily attached to the core material 31 by the simple task of wrapping and fixing the metal plate 41 around the shape of the core material 31.

In this embodiment, the metal plate 41 has multiple slits 47 formed therein that are spaced apart in the Y direction and extend from the tip surface cover portion 42 to the pair of side surface cover portions 43, 44. In this case, each divided portion P1 between each slit 47 is independently deformable. Therefore, when the recoater 21 receives a reaction force in the X direction from the protruding portion P3 of the object 3, only the divided portion P1 that receives the reaction force can be deformed in the X direction. In this case, the pressing force applied by the recoater 21 to the object 3 can be more effectively reduced compared to when the entire metal plate 41 deforms in the X direction, thereby more reliably preventing deformation of the object 3 as the recoater 21 moves.

In this embodiment, the metal plate 41 is removably attached to the core material 31. In this case, even if the metal plate 41 is damaged, it is not necessary to replace the entire recoater 21; only the metal plate 41 needs to be replaced, thereby improving maintainability.

In this embodiment, the metal plate 41 has an outer surface 42a facing away from the tip surface 32, and the outer surface 42a is curved so as to bulge toward the surface 2a of the powder bed A when viewed from the Y direction. In this case, it is possible to prevent the recoater 21 from getting caught on the model 3 when the recoater 21 moves over the surface 2a of the powder bed A. As a result, it is possible to more reliably prevent the model 3 from being deformed as the recoater 21 moves.

The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit and scope of the present disclosure. For example, the direction of movement of the recoater moving over the surface of the powder bed is not limited to the X direction, but may be other directions within the XY plane. In the above-described embodiments, the recoater moves over a stationary table to level the surface of the powder bed, but the recoater may also be stationary on a rotating table to level the surface of the powder bed. In this case, the recoater moves relative to the surface of the powder bed in the circumferential direction around the center of the disk-shaped table as the center of rotation. The beam irradiated onto the powder by the irradiation device is not limited to an electron beam, and may be another energy beam (e.g., a laser).

In the above-described embodiment, the powder is metal powder. However, even if the powder material is other materials such as ceramic or resin, clumps of powder equivalent to spatter can adhere to the recoater during beam irradiation, providing the same effect as the above-described embodiment. In the above-described embodiment, the metal plate of the recoater covers the core material from its tip surface to two side surfaces, but the metal plate does not necessarily have to cover the sides of the core material. Furthermore, the member covering the core material does not have to be a metal plate. The member covering the core material can also be a thin plate made of a material other than metal (e.g., resin) as long as it is harder than the core material. The method of fixing the metal plate to the core material is not limited to screw fastening, and other fixing methods such as adhesive bonding can also be used.

1. Modeling device (additive manufacturing device)
2 Powder 2a Surface 4 Vacuum chamber (chamber)
5 table 8 irradiation device 20 recoater device 21 recoater 31 core material 32 tip surface 33, 34 side surface 41 metal plate (cover layer)
42 Tip surface cover portion 42a Outer surface 43, 44 Side surface cover portion 47 Slit 51 Recoater device portion (holder)
A powder bed

Claims (11)

A recoater apparatus for leveling the surface of a powder bed disposed on a main surface of a table, comprising:
a recoater positioned over the surface;
a holder that holds the recoater and moves the recoater relative to the surface in a first direction along the main surface,
The recoater is
a core material including a tip surface extending along the main surface and in a second direction intersecting the first direction, the core material being made of a material that elastically deforms upon receiving a reaction force from a shaped object formed on the main surface;
a cover layer that is arranged to cover at least the tip end surface and face the surface, and is made of a material harder than the core material;
The core material is made of rubber or silicone . The recoater device of claim 1, wherein the cover layer is a metal plate made of a metal material. The recoater device described in claim 1 or 2, wherein the cover layer has enough rigidity to be deformed when subjected to a reaction force from the object. the recoater further has a pair of side surfaces aligned in the first direction,
4. The recoater apparatus according to claim 3, wherein the cover layer has a tip surface cover portion that covers the tip surface, and a pair of side surface cover portions that extend from the tip surface and cover the pair of side surfaces. The recoater device described in claim 4, wherein the cover layer has a plurality of slits formed therein that are spaced apart in the second direction and extend from the tip surface cover portion to the pair of side surface cover portions. A recoater apparatus according to any one of claims 1 to 5, wherein the cover layer is removably attached to the core material. the cover layer has an outer surface facing away from the tip surface,
7. The recoater apparatus according to claim 1, wherein the outer surface is curved so as to bulge toward the front surface when viewed from the second direction. A recoater apparatus for leveling the surface of a powder bed disposed on a main surface of a table, comprising:
a recoater positioned over the surface;
a holder that holds the recoater and moves the recoater relative to the surface in a first direction along the main surface,
The recoater is
a core material including a tip surface extending along the main surface and in a second direction intersecting the first direction, the core material being made of a material that elastically deforms upon receiving a reaction force from a shaped object formed on the main surface;
a cover layer that is arranged to cover at least the tip end surface and face the surface, and is made of a material harder than the core material;
The cover layer has sufficient rigidity to be deformed by receiving a reaction force from the object. A recoater apparatus for leveling the surface of a powder bed disposed on a main surface of a table, comprising:
a recoater positioned over the surface;
a holder that holds the recoater and moves the recoater relative to the surface in a first direction along the main surface,
The recoater is
a core material including a tip surface extending along the main surface and in a second direction intersecting the first direction, the core material being made of a material that elastically deforms upon receiving a reaction force from a shaped object formed on the main surface;
a cover layer that is arranged to cover at least the tip end surface and face the surface, and is made of a material harder than the core material;
The cover layer is removably attached to the core material. A recoater apparatus for leveling the surface of a powder bed disposed on a main surface of a table, comprising:
a recoater positioned over the surface;
a holder that holds the recoater and moves the recoater relative to the surface in a first direction along the main surface,
The recoater is
a core material including a tip surface extending along the main surface and in a second direction intersecting the first direction, the core material being made of a material that elastically deforms upon receiving a reaction force from a shaped object formed on the main surface;
a cover layer that is arranged to cover at least the tip end surface and face the surface, and is made of a material harder than the core material;
the cover layer has an outer surface facing away from the tip surface,
The recoater apparatus, wherein the outer surface is curved so as to bulge toward the front surface when viewed from the second direction. a chamber;
a table disposed within the chamber and supporting a powder bed containing powder;
an irradiation device that irradiates the powder on the table with an energy beam;
and a recoater device according to any one of claims 1 to 10 , which is disposed in the chamber and levels the surface of the powder bed.