JP6283554B2 - 3D additive manufacturing equipment - Google Patents

Description

  The present invention relates to a three-dimensional additive manufacturing apparatus that forms a three-dimensional structure by repeatedly forming a solidified layer formed by solidifying a predetermined region of a powder material layer.

  As a modeling method of a conventional three-dimensional additive manufacturing apparatus, for example, a powder material is spread on the upper surface of a stage, which is a powder table, layer by layer. Next, only the two-dimensional structure corresponding to one cross section of the modeled object is melted by the melting mechanism composed of an electron beam or a laser on the powder material spread on the stage. Then, a modeled object is formed by stacking layers of such powder materials one by one in the height direction (Z direction).

  Next, an example of a conventional three-dimensional additive manufacturing apparatus will be described with reference to FIG. FIG. 10 is a schematic configuration diagram illustrating an example of a conventional three-dimensional additive manufacturing apparatus.

  As illustrated in FIG. 10, the three-dimensional additive manufacturing apparatus 200 includes a hollow processing chamber 202 that performs modeling processing, a stage 204 that is disposed in the processing chamber 202, and a discharge head 221 that discharges a powder material onto the upper surface of the stage 204. have. In addition, the three-dimensional additive manufacturing apparatus 200 includes a powder storage 225 that stores powder material, a transport pipe 226 that communicates the powder storage 225 and the discharge head 221, and the discharge head 221 from the powder storage 225 via the transport pipe 226. And a powder conveyance mechanism (not shown) for conveying the powder material.

  The ejection head 221 is supported by the first guide part 223 and the second guide part 224 so as to be movable in a direction parallel to one surface of the stage 204.

  Then, the powder is transported from the powder storage 225 to the discharge head 221 via the transport pipe 226 by the powder transport mechanism. Next, the ejection head 221 moves in a direction parallel to one surface of the stage 204 by the first guide part 223 and the second guide part 224. Then, the powder material is discharged on one surface of the stage 204 from the discharge head 221, so that the powder material is spread on one surface of the stage 204.

  Further, in Patent Document 1, a plate-shaped regulating member is moved in the horizontal direction on the upper surface of a modeling frame that forms a modeled object, and the powder material is conveyed to the upper surface of the stage, and the entire powder material has a constant thickness. A technique for spreading on the upper surface of the stage is disclosed.

JP 2001-152204 A

  However, in the three-dimensional additive manufacturing apparatus 200 shown in FIG. 10, there is a possibility that the powder material is clogged in the transport pipe 226 that communicates the powder storage 225 and the discharge head 221, and the powder material is stably transferred from the discharge head 221 to the stage 204. There was a problem that it became impossible to discharge.

  Accordingly, an object of the present invention is to provide a three-dimensional additive manufacturing apparatus that can stably supply a powder material to a stage.

  In order to solve the above-described problems and achieve the object of the present invention, the three-dimensional layered manufacturing apparatus of the present invention includes a stage to which a powder material for forming a model is formed on the surface, and a powder that spreads the powder material on the stage. A supply unit. The powder supply unit is a powder cartridge that stores powder material and discharges the powder material to the stage, and includes a powder cartridge having a heat insulating structure and a holding mechanism that detachably holds the powder cartridge.

  In the three-dimensional laminating apparatus of the present invention, since the powder cartridge has a heat insulating structure, the temperature of the powder material accommodated in the powder cartridge is properly maintained.

  According to the present invention, it is possible to obtain a three-dimensional additive manufacturing apparatus that can stably supply a powder material to a stage.

It is the schematic which shows the whole structure of the three-dimensional additive manufacturing apparatus which concerns on the 1st Embodiment of this invention. It is a schematic plan view (the 1) at the time of seeing the three-dimensional additive manufacturing apparatus which concerns on the 1st Embodiment of this invention from the upper surface. It is a schematic plan view (the 2) at the time of seeing the three-dimensional additive manufacturing apparatus which concerns on the 1st Embodiment of this invention from the upper surface. It is sectional drawing which shows the principal part of a powder supply unit. It is a block diagram which shows the control system of the three-dimensional additive manufacturing apparatus which concerns on the 1st Embodiment of this invention. It is a section lineblock diagram of a cartridge storage. It is the schematic which shows the whole structure of the three-dimensional additive manufacturing apparatus which concerns on the 2nd Embodiment of this invention. It is the schematic which shows the whole structure of the three-dimensional additive manufacturing apparatus which concerns on a modification. It is the schematic which shows the whole structure of the three-dimensional additive manufacturing apparatus which concerns on the 3rd Embodiment of this invention. It is a schematic block diagram which shows an example of the conventional three-dimensional additive manufacturing apparatus.

  Hereinafter, an example of a three-dimensional additive manufacturing apparatus according to an embodiment of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following examples.

<1. First Embodiment: Three-dimensional additive manufacturing apparatus>
[1-1. Overall configuration of 3D additive manufacturing equipment]
First, the three-dimensional additive manufacturing apparatus according to the first embodiment of the present invention will be described. FIG. 1 is a diagram illustrating an overall configuration of a three-dimensional additive manufacturing apparatus according to a first embodiment of the present invention.

  The three-dimensional additive manufacturing apparatus 1 shown in FIG. 1 irradiates a metal powder P such as titanium, aluminum, iron, etc. with an electron beam L1 to melt the metal powder P, and a layer in which the molten metal powder P is solidified. It is an apparatus that forms a three-dimensional shaped object M by stacking.

  The three-dimensional additive manufacturing apparatus 1 includes a hollow processing chamber 2, a modeling frame 3, a flat plate stage 4, a stage drive mechanism 5, a powder supply unit 7, an electron gun 8, and a cartridge storage 9. doing. Here, a direction parallel to one surface of the stage 4 is defined as a first direction X1, and a direction orthogonal to the first direction X1 and parallel to one surface of the stage 4 is defined as a second direction Y1. A direction orthogonal to one surface of the stage 4 is a third direction Z1.

  A vacuum pump (not shown) is connected to the processing chamber 2. The atmosphere in the processing chamber 2 is evacuated by a vacuum pump, so that the processing chamber 2 is maintained in a vacuum. In the processing chamber 2, a modeling frame 3, a stage 4, a stage drive mechanism 5, and a powder supply unit 7 are provided. A cartridge storage 9 is connected to one side of the processing chamber 2 in the first direction X1. An electron gun 8 is mounted on one side of the third direction Z1 of the processing chamber 2, and the modeling frame 3 is disposed on the other side of the third direction Z1.

  The modeling frame 3 is formed with pits 3a penetrating from one side to the other along the third direction Z1. The pit 3a is opened in a substantially quadrangular prism shape. Moreover, in order to be able to take out the completed molded article M, a part of the outer peripheral surface of the pit 3a in the modeling frame 3 is configured to be openable.

  A stage 4 and a stage drive mechanism 5 are arranged in the pit 3 a in the modeling frame 3. The stage 4 is a powder base on which the metal powder P for forming the shaped object M is stacked. Further, a sliding member 13 having heat resistance and flexibility is provided at a side end portion of the stage 4. The sliding member 13 is slidably in contact with the wall surface of the pit 3a. The sliding member 13 seals one space and the other space in the third direction Z1 in the stage 4.

  In addition, a shaft portion 4d is provided on the other surface opposite to one surface (hereinafter referred to as the surface 4a) on which the metal powder P is laminated in the stage 4. The shaft portion 4d protrudes from the other surface of the stage 4 toward the other side in the third direction Z1. The shaft portion 4d is connected to the stage drive mechanism 5 accommodated in the pit 3a. The stage drive mechanism 5 drives the stage 4 along the third direction Z1 via the shaft portion 4d. Examples of the stage drive mechanism 5 include a rack and pinion and a ball screw.

  The electron gun 8 is disposed to face the surface 4 a of the stage 4 on one side in the third direction Z1 of the processing chamber 2. The electron gun 8 has a metal powder P on the surface of the stage 4 in accordance with a two-dimensional shape obtained by slicing a design object prepared in advance (a model object represented by three-dimensional CAD (Computer-Aided Design) data) at ΔZ intervals. The electron beam L1 is emitted. By the electron beam L1 emitted from the electron gun 8, the metal powder P in the region corresponding to the two-dimensional shape is melted.

  Although not shown in FIG. 1, an external temperature detector 17 (see FIG. 5) that can detect the surface temperature of the layer made of the metal powder P spread on the stage 4 is provided inside the processing chamber 2. ing. The external temperature detector 17 detects the surface temperature of the metal powder P spread on the stage 4 and sends the detection signal to the controller 30 (see FIG. 5). The temperature in the reflection film 34 (see FIG. 4) provided on the outer peripheral surface of the powder cartridge 21 described later is determined by the radiant heat from the metal powder P spread on the stage 4. For this reason, by detecting the temperature of the metal powder P, the temperature of the outer peripheral surface of the powder cartridge 21 can be determined.

  Further, the powder supply unit 7 is arranged at a predetermined interval from the modeling frame 3 in one of the third directions Z1 with respect to the modeling frame 3.

[1-2. Powder supply unit]
Next, with reference to FIGS. 1-5, the detailed structure of the powder supply unit 7 is demonstrated. 2 and 3 are schematic plan views when the three-dimensional additive manufacturing apparatus 1 is viewed from above. FIG. 4 is a cross-sectional view showing the main part of the powder supply unit 7. Further, FIG. 5 is a block diagram showing a control system of the three-dimensional additive manufacturing apparatus 1.

  As shown in FIGS. 2 and 3, the powder supply unit 7 includes a powder cartridge 21, a holding mechanism 22, a pair of first guide parts 23, and a second guide part 24. The pair of first guide portions 23 and the second guide portions 24 constitute a moving mechanism.

  The pair of first guide portions 23 are disposed on both sides in the second direction Y1 with the stage 4 interposed therebetween. The pair of first guide portions 23 extends into the processing chamber 2 along the first direction X1. A pair of first guide portions 23 support a second guide portion 24 so as to be movable in the first direction X1.

  The second guide portion 24 extends along the second direction Y1 between the pair of first guide portions 23. The second guide portion 24 is electrically connected to the X-direction drive unit 10 (see FIG. 5) and is moved in the first direction X1 by the X-direction drive unit 10. Further, the holding mechanism 22 is supported by the second guide portion 24 so as to be movable in the second direction Y1. And the powder cartridge 21 is detachably held by the holding mechanism 22.

[Powder cartridge]
As shown in FIG. 4, the powder cartridge 21 is a container 20 for storing the metal powder P, which has a four-layer structure made of materials having different thermal conductivities, and a shutter provided at the tip of the container 20. A part 27 and a stirring part 29 for stirring the metal powder P accommodated in the container 20 are provided.

  The container 20 includes a container main body 31, a heat insulating layer 32, a heat insulating cooling layer 33, and a reflective film 34 that are sequentially provided on the outer peripheral surface of the container main body 31. The container body 31 is configured by a hollow member that can accommodate the metal powder P therein, and in this embodiment, is configured by a cylindrical member having a discharge port 31a for discharging the metal powder P toward the stage. ing. The inner wall surface of the container body 31 on the side of the discharge port 31a is formed in a tapered shape such that the inner diameter becomes narrower toward the discharge port 31a. Since the container body 31 performs temperature management of the metal powder P accommodated inside the container body 31 by a first cooling mechanism 48 (see FIG. 5) to be described later, the container body 31 can be made of a material having good thermal conductivity. In the present embodiment, a phosphor bronze material having a high Young's modulus is used. Further, DLC (diamond-like carbon) is formed on the inner wall surface of the container body 31. Thereby, mechanical interference with the container main body 31 and the metal powder P can be prevented, and polishing of the inner wall surface of the container main body 31 by the metal powder P can be prevented. And the bearing 39 of the stirring part 29 is provided in the opening end of the container main body 31 on the opposite side to the discharge port 31a.

  The container body 31 accommodates a single layer or a plurality of layers of metal powder P spread on the stage 4.

  Although not shown in FIG. 4, the container body 31 is provided with an internal temperature detector 16 (see FIG. 5) that can detect the temperature of the container body 31. The internal temperature detection unit 16 detects the temperature of the container body 31 and sends the detection signal to the control unit 30 (see FIG. 5). The internal temperature detection part 16 can take the structure which detects the temperature of the container main body 31 by measuring the thermal resistance of the container main body 31, for example. And the container main body 31 is cooled by the 1st cooling mechanism 48 mentioned later based on the temperature detected by the internal temperature detection part 16. FIG.

  The heat insulating layer 32 is provided outside the container body 31 and is made of a material having a lower thermal conductivity than the container body 31. By configuring the heat insulating layer 32 with a material having a lower thermal conductivity than the container body 31, it is possible to increase the thermal resistance as compared with the case where the container 20 is configured with only the container body 31. By providing the heat insulating layer 32 and increasing the thermal resistance of the container 20, it is possible to suppress an increase in temperature inside the container body 31 due to radiant heat from the metal powder P spread on the surface of the stage 4. In the present embodiment, the heat insulating layer 32 is made of titanium which is excellent in heat resistance and strength, is nonmagnetic and has low thermal conductivity.

  Since the heat insulation cooling layer 33 is provided outside the heat insulation layer 32 and exhausts heat using a second cooling mechanism 49 described later, the heat conductivity in the plane direction is larger than the heat conductivity in the thickness direction. It is made of a material having a heat conductivity. In the present embodiment, the heat insulating cooling layer 33 is configured using a highly oriented graphite sheet material. The highly oriented graphite sheet material has a characteristic that the thermal conductivity in the plane direction is 250 to 300 W / m · k, whereas the thermal conductivity in the thickness direction is 5 to 10 W / m · k. The ratio of the heat transferred in the plane direction and the heat transferred in the thickness direction is about 50: 1. Therefore, the heat generated in the adiabatic cooling layer 33 can be efficiently transmitted in the surface direction and exhausted by the second cooling mechanism 49 described later. In the present embodiment, a highly oriented graphite sheet material is used as the heat insulating cooling layer 33. In addition, as a material having thermal conductivity anisotropy, it is obtained by knitting carbon nanosheets or carbon fibers in the heat conduction direction. Sheet material can be used.

  The reflection film 34 is provided outside the heat insulating cooling layer 33 and is made of a material that reflects radiant heat from the metal powder P spread on the surface of the stage 4. In the present embodiment, the highly oriented graphite sheet material used for the heat insulating cooling layer 33 is a black body and has a large heat absorption, but by providing the reflective film 34, the radiant heat from the stage 4 side can be reflected. Radiant heating of the container 20 can be suppressed. In the present embodiment, the reflective film 34 is formed by coating the outer peripheral surface of the heat insulating cooling layer 33 with a thick film of aluminum and gold, and a heat wave having a wavelength λ = 1 to 20 μm can be reflected. It was.

  Moreover, the shutter part 27 covers the discharge port 31a of the container 20 so that opening and closing is possible, and as shown in FIG. The shutter drive unit 28 that drives the shutter unit 27 is provided, for example, in a holding mechanism 22 described later, and is connected to a control unit 30 (not shown) via a connection terminal (not shown) provided in the second guide unit 24. (See FIG. 5).

  The stirring unit 29 includes a rotating shaft 37, a rotating blade 36 provided at the tip of the rotating shaft 37, and a connecting portion 40 provided on the opposite side of the rotating shaft 37 from the side on which the rotating blade 36 is provided. . The rotating shaft 37 is rotatably supported through a bearing 38 in a bearing hole 39 a provided at the center of the bearing 39, and is inserted into the container body 31. The rotary blade 36 is fixed to one end of the rotary shaft 37 on the discharge port 31a side, and is disposed in the vicinity of the discharge port 31a. The rotary blade 36 is formed in a substantially conical shape, and a plurality of blades are provided radially. The end of the rotating shaft 37 opposite to the side on which the rotating blades 36 are fixed protrudes above the bearing 39, and the connecting portion 40 is provided at the end of the protruding rotating shaft 37. The connection part 40 is connected to the other connection part 43 of the holding mechanism 22 described later.

[Holding mechanism]
Next, the holding mechanism 22 constituting the powder supply unit 7 will be described. The holding mechanism 22 is connected to the holding unit 45 that attaches and detaches the container 20, the first cooling unit 41 that cools the temperature of the container body 31, the second cooling unit 42 that is connected to the adiabatic cooling layer 33, and the stirring unit 29. The rotation drive part 44 is provided.

  The holding portion 45 includes a rail engaging portion (not shown) that engages with a guide rail portion (not shown) of the second guide portion 24, and is provided on the second guide portion 24. It is electrically connected to the Y direction drive part 11 (refer FIG. 5) provided in the exterior of the powder supply unit 7 through the connected terminal (illustration omitted).

  The first cooling unit 41 is in thermal contact with the container body 31 and is provided with a first cooling device 14 (outside the processing chamber 2 via a first heat transfer member 46 provided in the second guide unit 24 ( (See FIG. 5). The 1st cooling part 41 is comprised with the member which can transfer heat, for example, can be comprised using the cooling pipe with which refrigerant | coolants, such as oil, circulate through the inside. Note that the first heat transfer member 46 that connects the first cooling device 14 and the first cooling unit 41 is a member that can transfer heat between the first cooling device 14 and the first cooling unit 41. For example, a highly oriented graphite sheet can be used. The first cooling unit 41 is cooled to a predetermined temperature by the first cooling device 14 described later under the control of the control unit 30.

  The second cooling unit 42 is in thermal contact with the heat insulating cooling layer 33, and the second cooling device 15 provided outside the processing chamber 2 via the second heat transfer member 47 provided in the second guide unit 24. (See FIG. 5). The second cooling unit 42 is insulated from the first cooling unit 41 through the space inside the holding mechanism 22. The 2nd cooling part 42 is comprised with the member which can transfer heat similarly to the 1st cooling part 41, for example, can be comprised using the cooling pipe with which refrigerant | coolants, such as oil, circulate through the inside. In addition, as the 2nd heat-transfer member 47 which connects the 2nd cooling device 15 and the 2nd cooling part 42, a highly oriented graphite sheet can be used, for example. The second cooling unit 42 is cooled to a predetermined temperature by the second cooling device 15 described later under the control of the control unit 30.

  The rotation drive unit 44 is connected to the connection unit 40 provided in the stirring unit 29 of the powder cartridge 21 through the connection unit 43. The rotation drive unit 44 is connected to the control unit 30 (see FIG. 5) via wiring not shown. As shown in FIG. 5, the rotation driving unit 44 rotates the stirring unit 29 under the control of the control unit 30. Thereby, the metal powder P accommodated in the container 20 is stirred. In the present embodiment, the discharge amount of the metal powder P can be controlled by the stirring operation of the stirring unit 29 by the rotation driving unit 44 and the opening / closing operation of the shutter unit 27.

[Control system]
As shown in FIG. 5, the control unit 30 controls each drive unit constituting the powder supply unit 7 and the first and second cooling devices 14 and 15, and is provided outside the processing chamber 2. For example, it is composed of a CPU (Central Processing Unit).

  The control unit 30 is connected to the shutter drive unit 28, the rotation drive unit 44, the X direction drive unit 10, and the Y direction drive unit 11, and each drive unit drives each unit under the control of the control unit 30. Further, the control unit 30 controls the temperature of the first cooling unit 41 by controlling the first cooling device 14 based on the detection signal sent from the internal temperature detection unit 16, and the temperature of the container body 31 is changed. Control it to an optimal value. Similarly, the control unit 30 controls the temperature of the second cooling unit 42 by controlling the second cooling device 15 based on the detection signal sent from the external temperature detection unit 17, and cools the adiabatic cooling layer 33. Then, the temperature of the outside of the container body 31 is controlled to an optimum value (by exhausting the heat of the heat insulating cooling layer 33).

  As the first cooling device 14, a heat exchanger such as a cooling fan can be used. In the present embodiment, as shown in FIG. 5, a first cooling mechanism 48 is configured by the first cooling unit 41 and the first cooling device 14. Further, as the second cooling device 15, a heat exchanger such as a cooling fan can be used. In the present embodiment, as shown in FIG. 5, the second cooling mechanism 49 is configured by the second cooling unit 42 and the second cooling device 15.

  By cooling the container main body 31 by the first cooling mechanism 48, it is possible to prevent the temperature inside the container main body 31 from rising, and it is possible to prevent the metal powder P from being altered or solidified inside the container main body 31. . Further, the heat of the adiabatic cooling layer 33 provided on the outer peripheral portion of the container main body 31 is exhausted to the outside by the second cooling unit 42, thereby preventing the temperature rise of the powder cartridge 21 due to the heat received from the stage 4 side. Can do. As described above, in the present embodiment, the surface of the stage 4 and the layer of the metal powder P spread on the surface of the stage 4 by the double cooling mechanism including the first and second cooling mechanisms 48 and 49, the powder cartridge 21, A large heat resistance can be provided between the metal powder P and the heat generation of the metal powder P in the powder cartridge 21 can be prevented.

[Cartridge hangar]
FIG. 6 is a cross-sectional view of the cartridge housing 9. As shown in FIG. 6, the cartridge storage 9 stores a plurality of new powder cartridges 21 filled with the metal powder P. In the cartridge storage 9, a plurality of powder cartridges 21 are held by the holding portion 61 of the rotating belt 60 and are held apart from each other. A heat insulating wall 18 is provided on the inner wall surface of the cartridge storage 9. Thereby, alteration of the metal powder P accommodated in the inside of the powder cartridge 21 temporarily stored in the cartridge storage 9 and clogging at the discharge port 31a can be prevented. The cartridge storage 9 is cooled by a cooling device (not shown).

  An exchange window 12 for discharging the powder cartridge 21 is formed on the processing chamber 2 side in the cartridge storage 9, and the powder cartridge 21 is delivered to the holding unit 45 of the holding mechanism 22 at the position of the exchange window 12. An exchange door (not shown) is attached to the exchange window 12, and this exchange door is opened when the cartridge is exchanged. A heat insulating wall is provided on the cartridge storage 9 side of the replacement door. After the powder cartridge 21 is delivered to the holding mechanism 22 at the position of the replacement window 12, the belt 60 is rotated so that the powder cartridge 21 to be delivered next is disposed at the position of the replacement window 12. Further, a cartridge collection box (not shown) is provided in the vicinity of the cartridge storage box 9. The used powder cartridge 21 with the metal powder P is discharged into the cartridge collection box.

  In addition, the used powder cartridge 21 can be reused by newly filling the used powder cartridge 21 collected in the cartridge collection box with the metal powder P. Further, the metal powder P remaining in the used powder cartridge 21 can also be reused.

[1-3. Operation of 3D additive manufacturing equipment]
Next, the operation of the three-dimensional additive manufacturing apparatus 1 having the above-described configuration will be described with reference to FIGS.

  First, as shown in FIG. 1, the stage 4 is disposed at a position lower by ΔZ in the third direction Z <b> 1 than the upper surface of the modeling frame 3 by the stage driving mechanism 5. This ΔZ corresponds to the layer thickness in the third direction Z1 of the metal powder P spread thereafter.

  Next, the cylindrical body 3a of the modeling frame 3 is preheated by a heater (not shown). By preheating the cylindrical body 3a of the modeling frame 3, the stage 4 and the surrounding atmosphere are preheated. Note that the preheating may be performed by irradiating the electron beam L1. In the case of preheating with the electron beam L1, the electron beam L1 is irradiated while scanning in a two-dimensional plane so that the surface of the stage 4 has a uniform temperature.

  Next, the powder supply unit 7 spreads the metal powder P having a thickness ΔZ on one surface of the stage 4. Specifically, as shown in FIG. 2, the holding mechanism 22 and the powder cartridge 21 are moved along the first guide portion 23 and the second guide portion 24 to the other side in the third direction Z <b> 1 of the stage 4. Then, the shutter drive unit 28 is driven under the control of the control unit 30 to open the shutter unit 27 of the powder cartridge 21 as shown in FIG. Thereby, the metal powder P accommodated in the powder cartridge 21 is discharged from the discharge port 31a to the surface 4a of the stage 4.

  Then, at the same time as discharging the metal powder P from the powder cartridge 21, the agitation unit 29 is rotated by driving the rotation driving unit 44 under the control of the control unit 30. Thereby, the metal powder P accommodated in the powder cartridge 21 is stirred, and the metal powder P is stably discharged to the stage 4 side without being clogged in the vicinity of the discharge port 31a. After the metal powder P is discharged onto the surface 4a of the stage 4, the layer of the metal powder P on the stage 4 is leveled by a blade (not shown) so as to be flat.

  Next, as shown in FIG. 1, an electron beam L1 is emitted from the electron gun 8 to the metal powder P. The electron gun 8 has an electronic design with respect to the metal powder P in accordance with a two-dimensional shape obtained by slicing a design object prepared in advance (a model object represented by three-dimensional CAD (Computer-Aided Design) data) at ΔZ intervals. The beam L1 is emitted. By the electron beam L1 emitted from the electron gun 8, the metal powder P in the region corresponding to the two-dimensional shape is melted.

  Next, the molten metal powder P is solidified after a predetermined time according to the material, and a solidified layer for one layer is formed. After the metal powder P for one layer is melted and solidified, the stage 4 is lowered by ΔZ by the stage drive mechanism 5. The movement of the stage 4 in the third direction Z1 is realized by the sliding member 13 sliding on the inner surface of the pit 3a of the modeling frame 3.

  Next, again by the powder supply unit 7, the powder cartridge 21 is moved to one side in the third direction Z1 of the stage 4, and the metal powder P for ΔZ is spread on the layer (lower layer) spread just before. Thereafter, the metal powder P in the region corresponding to the two-dimensional shape corresponding to the layer is melted by the electron beam L1 emitted from the electron gun 8. At this time, the molten metal powders are joined together and solidified together with the first solidified layer to form two solidified layers. As described above, the stage 4 is lowered, the metal powder P is supplied onto the stage 4, and the process of melting and solidifying the metal powder P is repeated, whereby the three-dimensional structure M is formed. 1 operation is completed.

  Here, the used powder cartridge 21 from which all of the contained metal powder P is discharged is collected in a cartridge collection box (not shown).

  Next, the holding mechanism 22 is inserted into the cartridge storage 9 through the replacement window 12 of the cartridge storage 9 and holds a new powder cartridge 21 filled with the metal powder P. When the powder cartridge 21 is delivered from the cartridge storage 9 to the holding mechanism 22, the belt 60 rotates in the cartridge storage 9, so that the powder cartridge 21 held next in the holding mechanism 22 is moved to the receiving position in the cartridge storage 9. stand by.

  According to the three-dimensional additive manufacturing apparatus 1 of the present embodiment, the metal powder P forming the model M is divided into one layer or a plurality of layers and accommodated in a plurality of powder cartridges 21. Thereby, since there is no need to provide a transport pipe for transporting the metal powder P, there is no problem that the metal powder P is clogged in the transport pipe, and the metal powder P can be constantly supplied to the stage 4 stably.

  By the way, as in this embodiment, when processing the metal powder P in the vacuum processing chamber 2, compared to processing the metal powder P in the processing chamber 2 into which an inert gas has been introduced under atmospheric pressure, The influence of heat radiation from the metal powder P due to the convection of the active gas is eliminated. For this reason, the melting temperature of the metal powder P under vacuum is about ½ of the melting temperature of the bulk metal. Therefore, under vacuum, the metal powder P can be dissolved by light energy at a lower temperature than under atmospheric pressure. However, in the conventional three-dimensional additive manufacturing apparatus 200 shown in FIG. 10, when the inside of the processing chamber 202 is evacuated, the melting temperature of the metal powder is lowered in the transport pipe 226 by the same action. For this reason, there remains a possibility that the powder stability in the transport pipe 226 is impaired by the influence of radiant heat.

  On the other hand, in the present embodiment, the container 20 constituting the powder cartridge 21 has a four-layer structure made of materials having different thermal conductivities, and a heat insulating layer 32 and a heat insulating cooling layer are formed on the outer peripheral surface of the container main body 31. It has the heat insulation structure where 33 is arrange | positioned. Thereby, it can prevent that the inside of the container main body 31 is heated by the influence of a radiant heat. Moreover, in this embodiment, since the container main body 31 is comprised by the 1st cooling mechanism 48 so that cooling is possible, it can prevent the metal powder P accommodated in the inside of the container main body 31 being heated and solidifying. Furthermore, in this embodiment, since the heat insulation cooling layer 33 provided in the outer periphery of the container main body 31 is configured to be cooled by the second cooling mechanism 49, the radiant heat is not easily transmitted to the container main body 31, and the container main body 31 is Heating by radiant heat can be prevented.

  Furthermore, the metal powder P necessary for modeling the molded object M can be divided into a plurality of powder cartridges 21 and managed. That is, storage and management of the metal powder P can be facilitated. Furthermore, it is possible to prevent the metal powder P from being wasted.

<2. Second Embodiment: Three-dimensional additive manufacturing apparatus having a dome-shaped processing chamber>
Next, a three-dimensional additive manufacturing apparatus according to the second embodiment of the present invention will be described. FIG. 7 is a schematic configuration diagram of a three-dimensional additive manufacturing apparatus 70 according to the second embodiment of the present invention. The three-dimensional additive manufacturing apparatus 70 of the present embodiment is different from the first embodiment in that the laser light source 77 is used as an energy beam generator for melting the metal powder and the processing chamber 71. In FIG. 7, parts corresponding to those in FIG.

  In the present embodiment, as shown in FIG. 7, the processing chamber 71 has a shape in which the inner wall surface of the upper portion of the processing chamber 71 facing the surface on which the metal powder P of the stage 4 is laminated is curved in a dome shape. That is, the inner wall surface of the upper portion of the processing chamber 71 facing the surface of the stage 4 of the processing chamber 71 has a spherical shape curved toward the stage 4 from the center to the side periphery. In addition, an energy beam transmission window 74, a heat ray incident window 75, and a temperature detection window 76 are provided at predetermined positions above the processing chamber 2, and an opening is provided in a part of the processing chamber 71. It is configured by fitting a transmission member so as to close it.

  Further, on the inner wall surface at the top of the processing chamber 71, a wall heat insulating cooling layer 72 and a wall surface reflecting film 73 are provided in this order from the inner wall surface side. The wall surface adiabatic cooling layer 72 can be composed of the same material as the adiabatic cooling layer 33 constituting the powder cartridge 21, and the wall surface reflecting film 73 is composed of the same material as the reflecting film 34 constituting the powder cartridge 21. I can. The wall surface adiabatic cooling layer 72 is in thermal contact with a cooling device (not shown), and is cooled and maintained at a predetermined temperature by being controlled by the control unit 30 in the same manner as the second cooling device 15.

  Further, a vacuum pump (not shown) is connected to the processing chamber 71. Then, the atmosphere in the processing chamber 71 is evacuated by the vacuum pump, so that the processing chamber 71 is maintained in a vacuum.

  A laser light source 77, a heat ray generator 78, and a temperature detector 79 are disposed outside the processing chamber 71. Laser light emitted from the laser light source 77 passes through the energy beam transmission window 74 and is irradiated on the surface of the stage 4. The heat ray generator 78 irradiates heat rays that heat the surface of the layer of the metal powder P spread on the surface 4 a of the stage 4, and the heat rays emitted from the heat ray generator 78 pass through the heat ray incident window 75. The light is transmitted and irradiated onto the surface 4 a of the stage 4. The temperature detection device 79 is configured by a device capable of measuring a two-dimensional plane temperature such as an IR camera, for example, and the surface of the metal powder P spread on the surface 4a of the stage 4 via the temperature detection window 76. Detect temperature.

  In the present embodiment, after the metal powder P is spread on the surface 4 a of the stage 4, heat rays are emitted from the heat ray generator 78 provided outside the processing chamber 71, and the metal powder P spread on the surface 4 a of the stage 4. Preheating of the metal powder P is performed by secondarily scanning on the surface. Thereafter, a model M is created on the surface 4a of the stage 4 in the same manner as in the first embodiment.

  By the way, when using an inorganic substance (metal etc.) as a powder material which forms the molded article M, there is a temperature difference between the melting temperature and the recombination temperature. Thereby, a big temperature difference arises between the fusion | melting part of the metal powder P, and the solidification layer formed in the front | former stage located in the lower layer, and distortion generate | occur | produces in the molded article M formed. For this reason, the conventional three-dimensional additive manufacturing apparatus has a configuration that preheats the metal powder spread on the stage with a heater or heat rays and prevents processing distortion due to a temperature difference between the molten portion and the solidified layer below it. Taken. However, when the stage surface is preheated, the processing chamber is affected by radiant heat, and a relative positional shift occurs within the range of the coefficient of thermal expansion of the material constituting the processing chamber, leading to a decrease in processing accuracy.

  On the other hand, in this embodiment, even when the metal powder P spread on the surface 4a of the stage 4 is preheated by providing the wall surface adiabatic cooling layer 72 and the wall surface reflection film 73 on the inner wall surface of the processing chamber 71. The influence of the heat that the processing chamber 71 receives can be reduced.

  Further, in the case where the vicinity of the stage 4 is heated by the heater and the metal powder P spread on the surface 4a of the stage 4 is preliminarily heated, if the model M becomes large, the surface 4a of the stage 4 and the molten portion of the surface of the metal powder P The distance increases gradually. As a result, when preheating is performed with a heater that heats the vicinity of the stage 4, there is a problem that the metal powder P in the molten portion is not preheated. In addition, when processing is performed in the vacuum processing chamber 71, the surface of the metal powder P is a vacuum interface, and in-vacuum melting conditions that are not affected by heat dissipation due to convection are generated. Therefore, it is necessary to appropriately control the temperature. is there.

  On the other hand, in the present embodiment, the preheating of the surface of the metal powder P spread on the surface 4 a of the stage 4 is performed by irradiation with heat rays from the heat ray generator 78. For this reason, also when forming the modeling object M with a large size, the preheating of the metal powder P in a fusion | melting part can be performed. Furthermore, in this embodiment, the temperature detector 79 appropriately detects the temperature of the surface of the metal powder P spread on the surface of the stage 4, and based on the detection result, the irradiation rate of the heat rays from the heat ray generator 78, Appropriate melting conditions can be maintained by controlling the irradiation intensity.

  Furthermore, as in this embodiment, when metal powder is employed as the powder material for forming the shaped object M, the metal reflects heat waves, so the metal powder has poor heat absorption efficiency, and the surface of the metal powder is There is a problem that it is difficult to be heated.

  On the other hand, in this embodiment, the inner wall surface facing the surface 4a of the stage 4 of the processing chamber 71 has a spherical shape, and the wall reflecting film 73 is formed on the inner wall surface. As a result, the radiant heat from the surface of the metal powder P spread on the stage 4 at the time of preheating is reflected by the wall surface reflection film 73 and irradiated onto the stage 4 again. As a result, the surface of the metal powder P spread on the stage 4 is reheated by the heat reflected by the wall reflecting film 73, and the temperature of the surface of the metal powder P can be prevented from decreasing. Thereby, the energy efficiency by the preheating of the metal powder P improves, and an energy saving process is attained.

[2-1. Modified example]
Next, a three-dimensional additive manufacturing apparatus according to a modification of the present embodiment will be described. FIG. 8 is a schematic configuration diagram of a three-dimensional additive manufacturing apparatus according to a modification. The three-dimensional additive manufacturing apparatus 80 according to the modification differs from the present embodiment in that a charged particle generator 81 is used as an energy generator. In FIG. 8, parts corresponding to those in FIG.

  In the modification, a charged particle generator 81 that emits a charged particle beam is used as an energy beam generator for melting the metal powder P. The charged particle generator 81 is attached to an opening 82 provided in the processing chamber 71. The charged particle beam irradiated from the charged particle generator 81 passes through the opening 82 of the processing chamber 71 and is irradiated onto the surface of the metal powder P spread on the surface 4 a of the stage 4.

  As described above, when the shaped article M is formed by the energy beam emitted from the charged particle generator 81, the charged particle generator is configured so that the energy beam is incident on the inside of the processing chamber 71 from the opening 82 of the processing chamber 71. 81 is mounted. In the modified three-dimensional additive manufacturing apparatus 80, a three-dimensional structure M is formed by the same operation as in the second embodiment.

  When a charged particle beam is used as an energy beam for melting the metal powder P as in the modification, the metal powder P may be charged by the charged particle beam and the metal powder P may be dissipated. In order to prevent such charging of the metal powder P, the three-dimensional additive manufacturing apparatus 80 according to the modified example is preheated to a temperature at which the supply electronic coupling condition of the metal powder P spread on the surface 4a of the stage 4 is generated. It is preferable.

  In the three-dimensional additive manufacturing apparatus 80 according to the modified example, the metal powder P inside the powder cartridge 21 can be maintained at an appropriate temperature, so that the stage is performed without solidifying the metal powder P inside the powder cartridge 21. It is possible to preheat the metal powder P on the four surfaces. For this reason, charging of the metal powder P can be prevented. And also in the three-dimensional additive manufacturing apparatus 80 which concerns on a modification, the effect similar to 2nd Embodiment can be acquired.

  By the way, when metal powder is used as the powder material, a physically or chemically bonded gas adheres to the surface of the metal powder. When the metal powder is heated under reduced pressure, particularly under high vacuum, the gas is separated from the metal powder at a temperature corresponding to the binding energy between the metal powder and the gas adhering to the metal powder. For example, when iron is used as the metal powder, oxygen adheres to the powder surface. Then, when the oxidized iron is heated to 450K under vacuum conditions, a reducing action is generated in which oxygen is desorbed from the iron surface. Therefore, in the next embodiment, a three-dimensional additive manufacturing apparatus that can prevent the influence of desorbed gas will be described.

<3. Third Embodiment: Three-dimensional additive manufacturing apparatus>
FIG. 9 is a schematic configuration diagram of a three-dimensional additive manufacturing apparatus according to the third embodiment of the present invention. The three-dimensional additive manufacturing apparatus 90 of the present embodiment is different from the second embodiment in that a desired gas is introduced into the processing chamber 71. In FIG. 9, parts corresponding to those in FIG.

  The three-dimensional additive manufacturing apparatus 90 of the present embodiment includes a gas introduction unit 92 attached to the processing chamber 71 and a pressure measurement device 91. The gas introduction unit 92 includes a connection port 93 connected to a gas generator (not shown) provided outside the processing chamber 71 and a gas pipe 94 for introducing gas into the processing chamber 71. The pressure measuring device 91 is a device that can measure the pressure inside the processing chamber 71. The three-dimensional additive manufacturing apparatus 90 is provided with a control unit (not shown) that controls the partial pressure amount of the introduced gas introduced from the gas introduction unit 92, and the control unit is a pressure measurement device 91. Based on the measured pressure, the partial pressure amount of the gas introduced from the gas introduction unit 92 is controlled so that the pressure in the processing chamber 71 becomes a predetermined pressure.

  In the present embodiment, since the pressure in the processing chamber 71 can be maintained at a predetermined value, the influence of the desorption gas from the metal powder P can be reduced. Furthermore, since the three-dimensional layered modeling apparatus 90 of the present embodiment can introduce a desired gas, it can perform post-processing of the model M using the gas. Below, the case where the three-dimensional layered manufacturing apparatus 90 of this embodiment is used and the modeled object of stainless steel is formed using iron (Fe), nickel (Ni), and chromium (Cr) is demonstrated.

  It is known that when a stainless steel material is exposed to an environment with a temperature condition of 700 to 900 K, a “sensitization phenomenon” occurs in which a passive film on the surface is broken and is easily rusted. In order to prevent this, in the present embodiment, after forming the molded object M made of stainless steel, the moisture in the process chamber 71 becomes 800 ppm to 2.5% (volume%) from the gas introduction part 92 under the condition that the pressure is constant. The preheating temperature of the stage 4 is lowered to 900 to 500K while introducing an inert gas containing. Thereby, a dense chromium oxide film can be generated on the surface of the molded article M made of stainless steel.

  As described above, in the three-dimensional additive manufacturing apparatus 90 of the present embodiment, after the model M made of stainless steel is completed in the processing chamber 71, a dense chromium oxide film is continuously generated on the surface of the model M. it can. Thereby, it is not necessary to perform the desensitization process with respect to the molded article M separately. Note that the chromium oxide film may be formed after the metal powder P around the shaped object M is removed.

  In the first to third embodiments described above, the powder supply unit 7 is configured to include one powder cartridge 21, but may be configured to include a plurality of powder cartridges 21. In that case, for example, the plurality of holding mechanisms 22 are supported by the second guide portion 24 so as to be movable along the second direction Y1, and the powder cartridge 21 is held by these holding mechanisms 22. Thereby, the powder material can be supplied from the plurality of powder cartridges 21 to the surface of the stage 4.

  When the powder supply unit 7 includes a plurality of powder cartridges 21, different powder materials may be accommodated in each powder cartridge 21, or all the same powder materials may be accommodated.

  In the first to third embodiments described above, the metal powder is used as the powder material. However, a resin or the like may be used.

  In the first to third embodiments described above, the container constituting the powder cartridge has a four-layer structure. However, the container has a heat insulating structure and can appropriately maintain the temperature of the powder material housed in the powder cartridge. If it is a structure, various changes are possible.

  In the first to third embodiments described above, the powder cartridge has a configuration including a stirring unit, but the stirring unit may not be configured. Further, the powder cartridge 21 may be provided with various other mechanisms such as a vibration mechanism that vibrates the container 20 and a regulating member that partitions the inside of the container body 31 and regulates the amount of powder material discharged from the discharge port 31a. .

  DESCRIPTION OF SYMBOLS 1,70,80,90 ... Three-dimensional additive manufacturing apparatus, 2,71 ... Processing chamber, 3 ... Modeling frame, 3a ... Pit, 4 ... Stage, 4d ... Shaft part, 5 ... Stage drive mechanism, 7 ... Powder supply unit 8 ... an electron gun, 9 ... a cartridge storage, 10 ... an X direction drive unit, 11 ... a Y direction drive unit, 12 ... an exchange window, 13 ... a sliding member, 14 ... a first cooling device, 15 ... a second cooling device, DESCRIPTION OF SYMBOLS 16 ... Internal temperature detection part, 17 ... External temperature detection part, 20 ... Container, 21 ... Powder cartridge, 22 ... Holding mechanism, 23 ... 1st guide part, 24 ... 2nd guide part, 27 ... Shutter part, 28 DESCRIPTION OF SYMBOLS ... Shutter drive part, 29 ... Stirring part, 30 ... Control part, 31 ... Container body, 31a ... Outlet, 32 ... Heat insulation layer, 33 ... Heat insulation cooling layer, 34 ... Reflection film, 36 ... Rotary blade, 37 ... Rotating shaft , 40 ... connection part, 41 ... first cooling part, 42 ... second cooling , 43 ... connection part, 44 ... rotation drive part, 45 ... holding part, 46 ... first heat transfer member, 47 ... second heat transfer member, 48 ... first cooling mechanism, 42 ... second cooling mechanism, 60 ... belt , 70 Three-dimensional additive manufacturing apparatus, 72 ... Wall heat insulation cooling layer, 73 ... Wall reflection film, 74 ... Energy beam transmission window, 75 ... Heat ray incident window, 76 ... Temperature detection window, 77 ... Laser light source, 78 ... Heat ray generator 79 ... Temperature detector, 81 ... Charged particle generator, 82 ... Opening, 91 ... Pressure measuring device, 92 ... Gas inlet, 93 ... Connection port, 94 ... Gas pipe

Claims (13)

A stage to which a powder material for forming a shaped object on the surface is supplied;
A powder supply unit for spreading the powder material on the stage;
The powder supply unit includes:
A powder cartridge having a heat insulating structure and containing a powder material to be supplied to the stage;
A three-dimensional additive manufacturing apparatus comprising a holding mechanism that detachably holds the powder cartridge. The three-dimensional additive manufacturing apparatus according to claim 1, further comprising a control unit that controls a temperature inside the powder cartridge. The powder cartridge is an anisotropic heat conductive material provided in a container body in which a powder material is housed, and an outer peripheral portion of the container body, and having a thermal conductivity in a plane direction larger than a thermal conductivity in a thickness direction. The three-dimensional additive manufacturing apparatus according to claim 1, further comprising: a formed heat insulation cooling layer. The powder cartridge is an anisotropic heat conductive material provided in a container body in which a powder material is housed, and an outer peripheral portion of the container body, and having a thermal conductivity in a plane direction larger than a thermal conductivity in a thickness direction. A heat insulating cooling layer formed
The three-dimensional additive manufacturing apparatus according to claim 2. The three-dimensional additive manufacturing apparatus of Claim 3 or 4 provided with the cooling mechanism which cools the said container main body and / or the said heat insulation cooling layer. A first cooling mechanism for cooling the container body;
A second cooling mechanism for cooling the adiabatic cooling layer,
The three-dimensional additive manufacturing apparatus according to claim 4 , wherein the control unit individually controls the first cooling mechanism and the second cooling mechanism. An internal temperature detector for detecting the temperature of the container body;
An external temperature detection device for detecting the temperature of the powder material spread on the stage,
The control unit controls the first cooling mechanism and the second cooling mechanism based on detection signals from the internal temperature detection unit and the external temperature detection device so that the inside of the container body has a predetermined temperature. The three-dimensional additive manufacturing apparatus according to claim 6 . The three-dimensional additive manufacturing apparatus according to any one of claims 3 to 7 , wherein a reflective film that reflects radiant heat generated from the powder material spread on the stage is provided on an outer peripheral surface of the heat insulating cooling layer. A treatment chamber having an inner wall surface provided with a wall surface reflecting film that reflects radiant heat generated from the powder material spread on the stage;
The three-dimensional additive manufacturing apparatus according to any one of claims 1 to 8 , wherein the stage and the powder supply unit are arranged inside the processing chamber. The three-dimensional additive manufacturing apparatus according to claim 9 , wherein an inner wall surface of the processing chamber has a dome-shaped spherical surface. Between the inner wall surface and the wall surface reflecting layer in the processing chamber, according to claim thermal conductivity in the plane direction is provided with the exhaust heat layer formed of a large anisotropic thermal conductive material than the thermal conductivity in the thickness direction 10 The three-dimensional additive manufacturing apparatus described in 1. A light source for preheating the powder material spread on the surface of the stage by two-dimensionally scanning the focused light on the surface of the stage; and a surface temperature for measuring the surface temperature of the powder material packed on the surface of the stage With a measuring unit,
The control unit controls the irradiation of the focused light from the light source to the stage surface so that the surface temperature of the powder material becomes a predetermined value based on the measurement value of the surface temperature measured by the surface temperature measurement unit. The three-dimensional additive manufacturing apparatus according to claim 2 . The three-dimensional additive manufacturing apparatus according to claim 3, wherein a heat reflecting film that reflects radiant heat is provided on an outer peripheral surface of the heat insulating cooling layer.

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