Three dimensional laminating and shaping apparatus and control method for three dimensional laminating and shaping apparatus

Abstract

To provide a three dimensional additive manufacturing apparatus capable of suppressing a temperature gradient of a powder material to be melted, and a method for controlling the three dimensional additive manufacturing apparatus.SOLUTION: The three dimensional PBF-AM apparatus 1 includes a shaping plate 22, a powder supply device 16, a beam irradiation device 2, and a control unit 104. The control unit 104 controls the irradiation device. Further, when a predetermined timing is reached in melting the powder material, the irradiation device is controlled to interrupt the melting treatment of the powder material, and a preheating treatment for preheating the powder material is performed.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a three-dimensional additive manufacturing device that builds a structure by stacking thin layers of powder material on a stage one by one, and a method for controlling the three-dimensional additive manufacturing device. [Background technology]

[0002] In recent years, 3D additive manufacturing technology, which creates objects by stacking thin layers of powder material one by one, has been attracting attention, and many types of 3D additive manufacturing technology have been developed, depending on the powder material and manufacturing method.

[0003] In a conventional 3D additive manufacturing device, for example, powder material is spread layer by layer on a base plate installed on the upper surface of a stage. Next, only the two-dimensional structure portion of the powder material spread on the base plate, which corresponds to one cross section of the object, is melted using a heating mechanism consisting of an electron beam or laser. Then, the layer of powder material is stacked one by one in the height direction (Z direction) to form the object (see, for example, Patent Document 1).

[0004] Patent Document 1 also describes a technology including a shaping plate, a powder coating device that coats the shaping plate with metal powder to form a powder layer, a beam irradiation device that irradiates the powder layer with an electron beam, and a control unit that controls the powder coating device and the beam irradiation device. When preheating the powder layer by irradiating it with an electron beam, the control unit sets the beam size and irradiation position of the electron beam so that electron beam lines do not overlap at least at the start of preheating, and controls the beam irradiation device so that at least one of the beam current and beam size of the electron beam gradually increases from the start to the end of preheating. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-13543 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the technology described in Patent Document 1, the preheating process of heating the powder material before melting it is not performed until the melting process of all the powder material in one layer of the molded object is completed. As a result, in the case of a molded object with a relatively large molding area, the temperature of the powder material decreases from the start to the end of the melting process, causing variations in the temperature during melting within the molded surface.

[0007] Furthermore, when multiple objects are manufactured, the powder material for one object is melted first, and then the powder material for the other objects is preheated. Even in this case, if the sizes of the surfaces of the multiple objects differ, variations in the melting temperatures occur between the objects with large surfaces and those with small surfaces.

[0008] In consideration of the above problems, an object of the present invention is to provide a three-dimensional additive manufacturing device and a method for controlling a three-dimensional additive manufacturing device that can suppress variations in the melting temperature of powder material. [Means for solving the problem]

[0009] In order to solve the above problems and achieve the object of the present invention, a 3D additive manufacturing apparatus of the present invention is a 3D additive manufacturing apparatus that manufactures a molded object. The 3D additive manufacturing apparatus includes a manufacturing plate, a powder supplying device, an irradiation device, and a control unit. The powder supplying device supplies powder material to the manufacturing plate to form a powder layer. The irradiation device irradiates the powder layer with a primary beam. The control unit controls the irradiation device. When a predetermined timing is reached during melting of the powder material, the control unit controls the irradiation device to interrupt the melting process of the powder material and perform a preheating process to preheat the powder material.

[0010] Furthermore, a control method for a three-dimensional additive manufacturing apparatus according to the present invention is a control method used for a three-dimensional additive manufacturing apparatus having the above-described configuration, and includes the following processes (1) and (2). (1) Processing to supply powder materials. (2) A process in which a powder material is irradiated with a primary beam to melt the powder material. When the powder material is melted, at a predetermined timing, the melting process of the powder material is interrupted and a preheating process is carried out to preheat the powder material. [Effects of the Invention]

[0011] According to the three-dimensional additive manufacturing device and the method for controlling the three-dimensional additive manufacturing device of the present invention, it is possible to suppress variations in the melting temperature of the powder material. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view showing a three-dimensional additive manufacturing apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of the configuration of a control system of a three-dimensional additive manufacturing apparatus according to an embodiment of the present invention. [Figure 3] 4 is a flowchart showing an example of a modeling operation of the three-dimensional additive manufacturing apparatus according to the embodiment of the present invention. [Figure 4] 4 to 4C are explanatory views showing a first operation example (full surface heating) of the preheating operation during the main sintering step in the modeling operation of the three-dimensional additive manufacturing apparatus according to the embodiment of the present invention. [Figure 5] 10 is a flowchart showing a main sintering step in the modeling operation of the three-dimensional additive manufacturing apparatus according to the embodiment of the present invention. [Figure 6] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 7] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 8] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 9] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 10] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 11] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 12] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 13] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 14] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 15] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 16] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 17] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 18] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 19] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 20] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 21] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 22] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 23] FIG. 4 is an explanatory diagram showing a first operation example of the main sintering step. [Figure 24] 24 to 24C are explanatory diagrams showing a second operation example (local heating) of the preheating operation during the main sintering step in the operation procedure of the three-dimensional additive manufacturing device according to the embodiment of the present invention. [Figure 25] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 26] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 27] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 28] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 29]FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 30] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 31] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 32] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 33] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. [Figure 34] FIG. 10 is an explanatory view showing a second operation example of the main sintering step. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of a three-dimensional additive manufacturing device and a method for controlling a three-dimensional additive manufacturing device according to the present invention will be described with reference to Figures 1 to 34. Note that common members in the figures are given the same reference numerals.

[0014] 1. Example of implementation 1-1.Configuration of 3D additive manufacturing equipment First, a three-dimensional additive manufacturing device according to an embodiment of the present invention (hereinafter referred to as "this example") will be described with reference to FIG. Fig. 1 is a schematic cross-sectional view showing a three-dimensional additive manufacturing apparatus according to this embodiment. In the following description, in order to clarify the shapes and positional relationships of the various components of the three-dimensional additive manufacturing apparatus, the left-right direction in Fig. 1 is referred to as the X direction, the depth direction in Fig. 1 as the Y direction, and the up-down direction in Fig. 1 as the Z direction. The X direction, Y direction, and Z direction are perpendicular to each other. Furthermore, the X direction and Y direction are parallel to the horizontal direction, and the Z direction is parallel to the vertical direction.

[0015] The 3D additive manufacturing device 1 shown in Figure 1 is a device that irradiates powder material, such as titanium, aluminum, iron, or other metal powder, with an electron beam to melt the powder material, and then stacks the solidified layers of this powder material to form a three-dimensional object.

[0016] 1, the 3D additive manufacturing apparatus 1 includes a vacuum chamber 3, a beam irradiation device 2, a powder supplying device 16, a modeling table 18, a modeling box 20, and a collection box 21. The 3D additive manufacturing apparatus 1 also includes a modeling plate 22, an inner base 24, a plate moving device 26, a radiation shield cover 28, a mask cover 30, a camera 42, and a shutter 44. The 3D additive manufacturing apparatus 1 also includes a plurality of detection units 46 that detect reflected electrons, which are an example of electrons.

[0017] The vacuum chamber 3 is a chamber for creating a vacuum state by evacuating the air inside the chamber with a vacuum pump (not shown).

[0018] The beam irradiation device 2 is a device that irradiates an electron beam 15 onto a build surface 32a of a powder layer formed from a build plate 22 or a powder material 32. The build surface 32a corresponds to the upper surface of the powder layer. The state of the powder layer changes as the 3D additive manufacturing process progresses. Although not shown, the beam irradiation device 2 has an electron gun that generates the electron beam 15, a focusing lens that focuses the electron beam generated by the electron gun, and a deflection lens that deflects the electron beam 15 focused by the focusing lens. The focusing lens is configured using a focusing coil and focuses the electron beam 15 by the magnetic field generated by the focusing coil. The deflection lens is configured using a deflection coil and deflects the electron beam 15 by the magnetic field generated by the deflection coil.

[0019] The powder supplying device 16 is a device that supplies powder material 32, which is an example of a powder material that serves as a raw material for the molded object 38, onto the molding plate 22 to form a powder layer. The powder supplying device 16 has a hopper 16a, a powder dropper 16b, and a squeegee 16c. The hopper 16a is a container for storing metal powder. The powder dropper 16b is a device that drops the powder material 32 stored in the hopper 16a onto the molding table 18. The squeegee 16c is an elongated member that is long in the Y direction and has a blade 16d for spreading the powder. The squeegee 16c spreads the powder material 32 dropped by the powder dropper 16b over the molding table 18. The squeegee 16c is movable in the X direction to spread the powder material 32 over the entire surface of the molding table 18.

[0020] The modeling table 18 is arranged horizontally inside the vacuum chamber 3. The modeling table 18 is arranged below the powder supply device 16. The center of the modeling table 18 is open. The shape of the opening of the modeling table 18 is circular in plan view or angular in plan view (for example, rectangular in plan view).

[0021] The modeling box 20 is a box that forms a space for modeling. The upper end of the modeling box 20 is connected to the edge of the opening of the modeling table 18. The lower end of the modeling box 20 is connected to the bottom wall of the vacuum chamber 3.

[0022] The recovery box 21 is a box for recovering the powder material 32 that has been supplied onto the modeling table 18 by the powder supplying device 16 in excess of what is needed.

[0023] The build plate 22 is a plate for forming a model (part) 38 using the powder material 32. The model 38 is formed by stacking on the build plate 22. The build plate 22 is formed to be circular or angular in plan view to match the opening shape of the build table 18. The build plate 22 is connected (grounded) to the inner base 24 by an earth wire 34 to prevent it from being electrically floating. The inner base 24 is maintained at GND (ground) potential. The powder material 32 is spread over the build plate 22 and the inner base 24.

[0024] The inner base 24 is provided so as to be movable in the vertical direction (Z direction). The shaping plate 22 moves vertically together with the inner base 24. The inner base 24 has larger outer dimensions than the shaping plate 22. The inner base 24 slides vertically along the inner surface of the shaping box 20. A sealing member 36 is attached to the outer periphery of the inner base 24. The sealing member 36 is a member that maintains slidability and airtightness between the outer periphery of the inner base 24 and the inner surface of the shaping box 20. The sealing member 36 is made of a heat-resistant and elastic material.

[0025] The plate moving device 26 is a device that moves the shaping plate 22 and the inner base 24 in the up-down direction. The plate moving device 26 includes a shaft 26a and a drive mechanism unit 26b. The shaft 26a is connected to the underside of the inner base 24. The drive mechanism unit 26b includes a motor and a power transmission mechanism (not shown), and moves the shaping plate 22 and the inner base 24 together with the shaft 26a in the up-down direction by driving the power transmission mechanism using the motor as a drive source. The power transmission mechanism is configured, for example, by a rack-and-pinion mechanism, a ball-screw mechanism, or the like.

[0026] The radiation shield cover 28 is disposed between the build plate 22 and the beam irradiation device 2 in the Z direction. The radiation shield cover 28 is made of a metal such as stainless steel. The radiation shield cover 28 shields against radiant heat generated when the electron beam 15 is irradiated onto the powder material 32 by the beam irradiation device 2. When the electron beam 15 is irradiated onto the powder material 32 for sintering, the powder material 32 melts. However, if the heat radiated from the build surface 32a of the powder layer at this time, i.e., the radiant heat, is widely dispersed within the vacuum chamber 3, thermal efficiency deteriorates. In contrast, when the radiation shield cover 28 is disposed above the build plate 22, the heat radiated from the build surface 32a is shielded by the radiation shield cover 28, and the shielded heat is reflected by the radiation shield cover 28 and returned to the build plate 22. This allows for efficient use of the heat generated by the irradiation of the electron beam 15.

[0027] The radiation shield cover 28 also functions to prevent evaporated material generated when the electron beam 15 is irradiated onto the powder material 32 from adhering (depositing) onto the inner wall of the vacuum chamber 3. When the electron beam 15 is irradiated onto the powder material 32, part of the molten metal turns into mist-like evaporated material and rises from the building surface 32a. The radiation shield cover 28 is arranged to cover the space above the building surface 32a to prevent this evaporated material from diffusing inside the vacuum chamber 3.

[0028] The mask cover 30 has an opening 30a and a mask portion 30b. When forming the molded object 38, the mask cover 30 is placed over the top surface of the powder material 32, i.e., the molded surface 32a. The opening 30a exposes the powder material 32 spread on the molded object 38, while the mask portion 30b shields the powder material 32 located outside the opening 30a. The shape of the opening 30a is set to match the shape of the molded object 22. For example, if the molded object 22 is circular in plan view, the opening 30a is set to be circular in plan view accordingly, and if the molded object 22 is rectangular in plan view, the opening 30a is set to be rectangular in plan view accordingly.

[0029] The mask cover 30 is disposed below the radiation shield cover 28. The opening 30a and mask portion 30b of the mask cover 30 are disposed between the build plate 22 and the radiation shield cover 28 in the Z direction. The mask cover 30 has an enclosure portion 30c. The enclosure portion 30c is disposed so as to enclose the space above the opening 30a. A portion (upper portion) of the enclosure portion 30c overlaps with the radiation shield cover 28 in the Z direction. The enclosure portion 30c functions to shield radiant heat generated from the build surface 32a and to suppress the diffusion of evaporated materials generated from the build surface 32a. In other words, the enclosure portion 30c functions similarly to the radiation shield cover 28.

[0030] The mask cover 30 is made of a metal with a higher melting point than the powder material 32 used as the raw material for the molded object 38. The mask cover 30 is also made of a material that is less reactive with the powder material 32. Titanium, for example, can be used as a material for the mask cover 30. The mask cover 30 may also be made of the same metal as the powder material 32 used. The mask cover 30 is electrically grounded to GND. The mask cover 30 serves as an electrical shield when the powder material 32 is pre-sintered by irradiating it with an electron beam 15 in a pre-heating step prior to the main sintering step, which will be described later, thereby minimizing powder scattering.

[0031] The camera 42 is a camera capable of capturing an image of the powder layer's building surface 32a. The camera 42 is positioned offset in the Y direction from the beam irradiation device 2 so as not to interfere with the position of the beam irradiation device 2. The camera 42 is preferably configured as a visible light camera such as a digital video camera. The camera 42 captures an image of the powder layer's building surface 32a to generate an image (image data) of the powder layer. Therefore, the image generated by the camera 42 is an image that shows the state of the powder layer's building surface 32a. The image is captured by the camera 42 with illumination light emitted by an illumination light source (not shown) included in the 3D additive manufacturing device 1 irradiating the powder layer's building surface 32a.

[0032] The shutter 44 protects the camera 42 and the observation window so that evaporated substances generated from the manufacturing surface 32a do not adhere to the camera 42 or the observation window when the powder material 32 is melted by irradiation with the electron beam 15. The camera 42 photographs the manufacturing surface 32a with the shutter 44 open. Furthermore, in processes in which evaporated substances are likely to be generated or in which a large amount of evaporated substances are generated, i.e., when the powder material 32 is melted by the electron beam 15, the shutter 44 is closed.

[0033] A plurality of detectors 46 for detecting reflected electrons are disposed below the beam irradiation device 2. Specifically, the detection unit 46 is disposed between the beam irradiation device 2 and the printing surface 32a of the object 38 to be formed on the printing plate 22. The position at which the detection unit 46 is provided is not limited to the example shown in Fig. 1, and the detection unit 46 may be disposed at various other positions.

[0034] 1-2. Control system of 3D additive manufacturing equipment Next, the configuration of the control system of the three-dimensional additive manufacturing apparatus 1 will be described with reference to FIG. FIG. 2 is a block diagram showing an example of the configuration of a control system of the three-dimensional additive manufacturing apparatus 1 of this embodiment. As shown in Figure 2, the 3D additive manufacturing device 1 has a polarization amplifier control circuit 101 which is an electron beam control unit, an analog-to-digital conversion circuit (ADC) 102, a preamplifier (Pre-AMP) 103, a personal computer (PC) 104 which is an example of a control unit, and a memory unit 105.

[0035] The polarization amplifier control circuit 101 is connected to the beam irradiation device 2 and a PC 104. The PC 104 transmits a control signal to the polarization amplifier control circuit 101 based on beam scanning information stored in a storage unit 105. The polarization amplifier control circuit 101 controls the beam irradiation device 2 based on the control signal. As a result, the beam irradiation device 2 irradiates the electron beam 15 at a predetermined position. The polarization amplifier control circuit 101 also transmits beam irradiation position information indicating the irradiation position of the electron beam 15 to the PC 104.

[0036] The Pre-AMP 103 is connected to the detection unit 46 and the ADC 102. The Pre-AMP 103 converts the reflected electron current detected by the detection unit 46 from a current signal to a voltage signal. The voltage signal converted by the Pre-AMP 103 is transmitted to the ADC 102. The ADC 102 converts the reflected electron signal, which has become a voltage signal, from an analog signal to a digital signal and transmits it to the PC 104.

[0037] The PC 104 also has an image processing unit (not shown). The image processing unit of the PC 104 captures images generated by the camera 42 and performs predetermined image processing on the captured images. The PC 104 then outputs the camera images that have been subjected to image processing by the image processing unit to a display unit (not shown).

[0038] The storage unit 105 stores modeling data of the model 38 to be modeled by the 3D additive manufacturing apparatus 1. The PC 104 then creates beam scanning information based on the modeling data and stores the created beam scanning information in the storage unit 105. Note that, although an example in which the beam scanning information is created by the PC 104 has been described, the present invention is not limited to this, and a user may create the beam scanning information based on the modeling data and store it in the storage unit 105.

[0039] Furthermore, the storage unit 105 stores a first operation example (full-surface heating treatment) and a second operation example (localized heating treatment) as operation examples of the preheating treatment performed during the main sintering step described below. Then, the PC 104 acquires a predetermined heating process (operation example) from the first operation example or the second operation example stored in the storage unit 105, and performs the main sintering step.

[0040] Furthermore, the storage unit 105 stores a preheating start threshold t heating or n heating The storage unit 105 also stores the elapsed time t during the main sintering process or the number of irradiation points n of the electron beam 15. The PC 104 then stores the pre-heating start threshold value t stored in the storage unit 105. heating or n heatingBased on the elapsed time t or the number of irradiation points n, the timing of the preliminary heating process to be performed during the main sintering step is determined.

[0041] 2. Example of operation of 3D additive manufacturing equipment 2-1.Modeling operation of 3D additive manufacturing equipment Next, an example of the modeling operation of the three-dimensional additive manufacturing device 1 having the above-described configuration will be described with reference to FIG.

[0042] FIG. 3 is a flowchart showing an example of the modeling operation of the three-dimensional additive manufacturing apparatus 1.

[0043] 3, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104. As a result, the beam irradiation device 2 operates based on a control command given from the polarization amplifier control circuit 101, thereby heating the shaping plate 22 (step S1). In step S1, the beam irradiation device 2 operates under the control of the polarization amplifier control circuit 101, thereby irradiating the shaping plate 22 with an electron beam 15 through the opening 30a of the mask cover 30. At this time, the polarization amplifier control circuit 101 defocuses the electron beam 15 using an objective lens or the like provided in the beam irradiation device 2. This defocusing is a state in which the focal position of the electron beam 15 is shifted below the upper surface of the modeling plate 22, that is, an underfocus state.

[0044] The polarization amplifier control circuit 101 also controls the beam irradiation device 2 to scan the electron beam 15 over an area wider than the opening 30a of the mask cover 30. As a result, the shaping plate 22 is heated by the irradiation of the electron beam 15. The shaping plate 22 is heated to a temperature at which the powder material 32 is pre-sintered. Once the shaping plate 22 has been heated to a predetermined temperature, the beam irradiation device 2 stops irradiating the electron beam 15. Note that scanning the electron beam 15 over an area wider than the opening 30a of the mask cover 30 means scanning the electron beam 15 over an area wider than the opening area of ​​the opening 30a so that the opening 30a fits within the scanning range (scanning area) of the electron beam 15. The scanning range (scanning area) of the electron beam 15 in the beam irradiation device 2 may be narrower than the opening 30a of the mask cover 30.

[0045] Next, the shaping plate 22 is lowered by a predetermined amount (step S2). In step S2, the plate moving device 26 lowers the inner base 24 by a predetermined amount so that the upper surface of the shaping plate 22 is slightly lower than the upper surface of the powder material 32 spread on the shaping table 18. At this time, the shaping plate 22 is lowered by the predetermined amount together with the inner base 24. The predetermined amount (hereinafter also referred to as "ΔZ") described here corresponds to the thickness of one layer when the shaped object 38 is shaped by stacking.

[0046] Next, the mask cover 30 is raised (step S3). In step S3, for example, the squeegee 16c is moved in the X direction to bring a cam follower (not shown) into contact with the inclined surface of a lifting member provided on the mask cover 30. As a result, the mask cover 30 is raised along the Z direction.

[0047] Next, the powder material 32 is spread all over the modeling plate 22 (step S4). In step S4, the powder supplying device 16 drops the powder material 32, which has been supplied from the hopper 16a to the powder dropper 16b, onto the modeling table 18 using the powder dropper 16b. Then, the powder supplying device 16 moves the squeegee 16c from one end to the other end in the X direction. This causes the powder material 32 to be spread all over the inner base 24. At this time, the powder material 32 is spread all over the modeling table 18 to a thickness equivalent to ΔZ. In addition, excess powder material 32 is collected in the collection box 21.

[0048] Next, the mask cover 30 is lowered (step S5). In step S5, the squeegee 16c is moved to a position where the cam follower of the squeegee 16c does not contact the lifting member. As a result, the mask cover 30 is lowered to the upper surface of the shaping plate 22. At this time, the powder material 32 spread on the shaping plate 22 is exposed to the outside through the opening 30a of the mask cover 30. In addition, the powder material 32 present around the shaping plate 22 is covered by the mask portion 30b of the mask cover 30.

[0049] Next, the powder material 32 is pre-sintered (step S6). In step S6, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104. As a result, the electron beam 15 is irradiated onto the powder material 32 on the build plate 22 through the opening 30a of the mask cover 30. At this time, the polarization amplifier control circuit 101 defocuses the electron beam 15 using an objective lens or the like provided in the beam irradiation device 2. This defocusing causes the focal position of the electron beam 15 to be shifted downward below the upper surface (build surface 32a) of the powder material 32, i.e., an underfocus state. In addition, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to scan the electron beam 15 over a wider area than the opening 30a of the mask cover 30. As a result, not only the powder material 32 exposed in the opening 30a but also the powder material 32 located outside the opening 30a (powder material 32 shielded by the mask portion 30b) are pre-sintered.

[0050] In this way, the process of pre-sintering the powder material 32 by covering the powder material 32 spread on the forming plate 22 with a mask cover 30 having an opening 30a and irradiating the powder material 32 with an electron beam 15 through the opening 30a corresponds to the first process. In this first step, the electron beam 15 is scanned over an area wider than the opening 30a of the mask cover 30, thereby pre-sintering at least all of the powder material 32 exposed to the opening 30a. Pre-sintering the powder material 32 also makes the powder material 32 conductive. This makes it possible to suppress powder scattering in the main sintering step that is performed after the pre-heating step.

[0051] Next, the powder material 32 is melted and solidified (step S7). In step S7, the powder material 32 that has been pre-sintered as described above is melted and solidified by irradiating it with the electron beam 15, thereby finally sintering the powder material 32 as a pre-sintered body. This step corresponds to the second step. In the second step, the beam irradiation device 2 selectively melts the powder material 32 on the build plate 22 by scanning the electron beam 15 based on the build data of the target object 38, i.e., two-dimensional data obtained by slicing three-dimensional CAD (Computer-Aided Design) data to a certain thickness. The powder material 32 that has been melted by irradiation with the electron beam 15 solidifies after the electron beam has passed. This completes the build of the first layer.

[0052] Next, the mask cover 30 is raised (step S8). Next, a backscattered electron image is acquired (step S9). In step S9, first, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104. As a result, the beam irradiation device 2 operates based on a control command given from the polarization amplifier control circuit 101, and scans the electron beam 15 over the pre-sintering region 39 where the pre-sintered powder material 32 exists and the model 38. At this time, the beam irradiation device 2 minimizes the electron beam current of the electron beam 15 and focuses the electron beam 15 on the modeling surface 32a. Then, the detection unit 46 detects the backscattered electrons generated by the electron beam 15.

[0053] The detector 46 outputs the detected backscattered electron signal to the PC 104 via the Pre-AMP 103. The image processor of the PC 104 then performs arithmetic processing on the backscattered electron signal (backscattered electron information) acquired from the detector 46 to acquire a backscattered electron image (BSE image). The image processor also stores the acquired BSE image in the memory 105.

[0054] Next, the mask cover 30 is lowered (step S10), and the build surface 32a is heated in preparation for spreading the powder material 32 (step S11). In step S11, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104. As a result, the beam irradiation device 2 operates based on a control command given by the polarization amplifier control circuit 101, and irradiates the build surface 32a with the electron beam 15 through the opening 30a of the mask cover 30. At this time, the polarization amplifier control circuit 101 defocuses the electron beam 15 using an objective lens or the like provided in the beam irradiation device 2. This defocusing results in a state in which the focal position of the electron beam 15 is shifted downward from the build surface 32a, i.e., an underfocus state.

[0055] The polarization amplifier control circuit 101 also controls the beam irradiation device 2 to scan the electron beam 15 over an area wider than the opening 30a of the mask cover 30. As a result, the electron beam 15 is irradiated onto the entire surface 32a to be molded that is exposed through the opening 30a. The surface 32a to be molded is heated to a temperature sufficient to temporarily sinter the powder material 32. Once the surface 32a to be molded has been heated to a predetermined temperature, the beam irradiation device 2 stops irradiating the electron beam 15.

[0056] Next, the shaping plate 22 is lowered by a predetermined amount (ΔZ) (step S12). In step S12, the plate moving device 26 lowers the inner base 24 by ΔZ so that the shaping surface 32a is slightly lower than the upper surface of the powder material 32 spread on the shaping table 18.

[0057] Next, the mask cover 30 is raised (step S13), and the powder material 32 is spread over the building plate 22 (step S14). In step S14, the powder supplying device 16 operates in the same manner as in step S4 above.

[0058] Next, the mask cover 30 is lowered (step S15), and the powder material 32 is pre-sintered (step S16). This step corresponds to step 1. In step S16, the beam irradiation device 2 operates in the same manner as in step S6.

[0059] When the preliminary sintering process of the powder material 32 is completed in the process of step S16, a backscattered electron image is acquired (step S17). In the process of step S17, similar to the process of step S9, the polarization amplifier control circuit 101 controls the beam irradiation device 2 and acquires a backscattered electron image (BSE image) by the detection unit 46. In the process of step S17, a backscattered electron image of the preliminary sintered body is acquired. Note that before the process of step S17, a process of raising the mask cover 30 is performed, and after the process of step S17, a process of lowering the mask cover 30 is performed.

[0060] Next, the powder material 32 is melted and solidified (step S18). This step corresponds to the second step. In step S18, the beam irradiation device 2 operates in the same manner as in step S7 above. This completes the formation of the second layer. The detailed operations of the main sintering step in steps S7 and S18 will be described later. The preheating treatment shown in steps S6 and S16 above is called preheating, and the preheating treatment shown in step S11 is called afterheating. The preheating treatment performed during steps S7 and S18 described later is called interval heating.

[0061] Thereafter, the processes of steps S8 to S18 are repeated until the formation of the object 38 is completed in step S19. The formation of the object 38 is completed when the powder material 32 has been melted and solidified for the number of layers required to form the object 38. In this way, the desired object 38 is obtained.

[0062] In the above-described example of operation, the operation of acquiring a BSE image is performed after the main sintering step in step S7 and after the processing in step S11, but the timing of performing the operation of acquiring a BSE image is not limited to this. For example, the operation of acquiring a BSE image may be performed after the preliminary sintering step in step S6.

[0063] During the main sintering steps of steps S7 and S18, that is, during the step of melting the powder material 32 and forming the shaped object 38, a preheating process is performed to heat the powder material 32.

[0064] 2-2. First operation example of this sintering process Next, a first operation example of the main sintering step will be described with reference to Fig. 4 to Fig. 23. Fig. 4A to Fig. 4C are explanatory diagrams showing a first operation example (full surface heating) of the preheating operation during the main sintering step. Note that in the example shown below, an example will be described in which a plurality of objects 38A, 38B, and 38C are formed as the object (part) 38.

[0065] Here, during the main sintering process of steps S7 and S18 in the operational example of Figure 3 described above, i.e., during the process of melting the powder material (hatch) 32, a pre-heating process is performed to heat the powder material 32 at a predetermined timing.

[0066] As shown in FIG. 4A, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104 to irradiate the powder material 32 with the electron beam 15. As a result, the powder material 32 is melted by the irradiation of the electron beam 15. When a predetermined timing is reached during the shaping process, the PC 104 outputs a control signal to the polarization amplifier control circuit 101 to interrupt the process of melting the powder material 32 with the electron beam 15. Note that the predetermined timing may be, for example, when the elapsed time t of the main sintering process or the number n of irradiation points of the electron beam 15 reaches a predetermined pre-heating start threshold t heating or n heating When it reaches

[0067] Next, as shown in FIG. 4B, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to preheat the powder material 32. At this time, the polarization amplifier control circuit 101 defocuses the electron beam 15 using an objective lens or the like provided in the beam irradiation device 2. Here, the first heating region H1 in the first operation example, i.e., full-surface heating, is the entire meltable area, as shown in FIG. 4B. Then, after the preheating process shown in FIG. 4B is completed, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104 to irradiate the powder material 32 with the electron beam 15, as shown in FIG. 4C. Then, the powder material 32 is melted again, and the sintering process is resumed.

[0068] Next, the main sintering step will be described with reference to Fig. 5 to Fig. 23. Fig. 5 is a flowchart showing the main sintering step. Fig. 6 to Fig. 23 are explanatory diagrams showing a first operation example of the main sintering step.

[0069] First, as shown in FIG. 5, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104 to switch the objects (parts) 38A, 38B, and 38C to be irradiated with the electron beam 15, and starts melting the powder material (hatch) 32 (step S21). The number of irradiation points n of the electron beam 15 and the elapsed time t1 are inherited from the previous objects 38A, 38B, and 38C (step S22). That is, the memory unit 105 stores the number of irradiation points n and the elapsed time t1 from the previous objects 38A, 38B, and 38C. In the case of the object 38A that is the first to undergo modeling processing on that layer, or when values ​​are not inherited between the objects 38A, 38B, and 38C, the number of irradiation points n is set to 0, and the elapsed time t1 is set to the time when the melting of the objects 38A, 38B, and 38C starts (step S23).

[0070] As a result, as shown in FIGS. 6 to 11, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104 to irradiate the powder material 32 with the electron beam 15. In this example, the electron beam 15 is irradiated onto the first object 38A. As shown in FIGS. 7 to 11, the polarization amplifier control circuit 101 scans the irradiation spot L1 of the electron beam 15 over the first object 38A. Here, the number of irradiation points n is the number of irradiation spots L1. Each irradiation spot L1 is irradiated with the electron beam 15 for a predetermined irradiation time. Then, as shown in FIGS. 7 to 11, the PC 104 counts the number of irradiation points n and the elapsed time t, and stores them in the memory unit 105.

[0071] Next, the PC 104 checks whether the number of irradiation points n stored in the storage unit 105 is equal to the preheating start threshold n heating In addition, the PC 104 determines whether the elapsed time t stored in the storage unit 105, that is, the time obtained by subtracting the time t1 at which the heating is completed from the time t2 at which the determination is made, is equal to or exceeds the pre-heating start threshold value t heating It is determined whether or not the value reaches (step S24).

[0072] In the process of step S24, if the PC 104 determines that the number of irradiation points n or the elapsed time t has not reached the preheating start threshold (NO determination in step S24), the process proceeds to step S31.

[0073] In the process of step S31, the polarization amplifier control circuit 101 selects the next irradiation point coordinates based on a control signal from the PC 104. Then, the PC 104 adds "1" to the number of irradiation points n (n+1) and stores it in the storage unit 105 (step S32). Then, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to move the irradiation spot L1 of the electron beam 15 to the irradiation point coordinates selected in step S31 (step S33). As a result, the irradiation spot L1 of the electron beam 15 moves as shown in FIGS. 7 to 11.

[0074] Next, the beam irradiation device 2 irradiates the powder material 32 with the electron beam 15 (step S34). As a result, the powder material 32 at the irradiation spot L1 is melted. When the irradiation process of the electron beam 15 in step S34 is completed, the PC 104 stores the time when the irradiation of the electron beam 15 is completed in the memory unit 105 as the determination time t2 (step S35). Then, when the process of step S35 is completed, the process returns to the determination process of step S24.

[0075] In the process of step S24, if the PC 104 determines that the number of irradiation points n or the elapsed time t has reached the pre-heating start threshold (YES determination in step S24), the process proceeds to step S25. In the process of step S25, the PC 104 acquires a preset heating process from the storage unit 105. The PC 104 determines whether the acquired heating process is local heating or full heating. In the following description, an example will be described in which the heating process is the first operation example (full heating).

[0076] In the process of step S25, if the PC 104 determines that the acquired heating process is full surface heating, the PC 104 sets the normal preheating region as the first heating region H1 and outputs a control signal to the polarization amplifier control circuit 101 (step S27). Next, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on the control signal from the PC 104 to start preheating (step S28).

[0077] That is, as shown in FIG. 11, when the number of irradiation points n or the elapsed time t reaches the preheating start threshold, the polarization amplifier control circuit 101 suspends the melting process of the powder material 32 after irradiation by the beam irradiation device 2. Then, as shown in FIGS. 12 and 13, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to scan the irradiation position L2 of the electron beam 15 within the range of the first heating region H1 set in the processing of step S27. This causes the powder material 32 to be preheated again. Then, when the specified time is reached, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to end the preheating (step S29).

[0078] When the process of step S29 is completed, the PC 104 sets the value of the number of irradiation points n stored in the storage unit 105 to "0." Alternatively, the PC 104 stores the time when the preheating is completed as the elapsed time t1 in the storage unit 105 (step S30). That is, the PC 104 resets the number of irradiation points n and the elapsed time t.

[0079] Then, when the processing of step S30 is completed, the processing of steps S31 and S32, i.e., the melting processing of powder material 32, is resumed. In step S31, as shown in Fig. 14, the polarization amplifier control circuit 101 selects irradiation position L2 of electron beam 15 as the coordinates of the next irradiation point from irradiation spot L1 where the melting processing was interrupted, as shown in Fig. 11. Then, as shown in Figs. 15 to 19, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to perform the melting processing of powder material 32 again until the number of irradiation points n or the elapsed time t reaches the pre-heating start threshold.

[0080] As described above, according to the 3D additive manufacturing apparatus 1 of this example, when a predetermined timing is reached during the melting process of the powder material 32 that constitutes one model 38A, the melting process is interrupted and a preheating process is performed. This makes it possible to reduce the variation in the temperature of the powder material 32 that melts first and the powder material 32 that melts last for models with a relatively large modeling surface. As a result, it is possible to reduce the variation in the temperature of the powder material 32 when it melts, thereby improving the quality of the completed model.

[0081] 17 and 18, if the melting process of the powder material 32 of the first object 38A is completed before the number of irradiation points n or the elapsed time t reaches the pre-heating start threshold, the PC 104 switches to the melting process of the powder material 32 of the second object 38B. Here, as shown in step S22 described above, the number of irradiation points n of the electron beam 15 and the elapsed time t1 are taken over from the first object 38A.

[0082] 19, when the number of irradiation points n or the elapsed time t reaches the preheating start threshold during the melting process of the powder material 32 of the second object 38B, the PC 104 outputs a control signal to the polarization amplifier control circuit 101. As a result, the polarization amplifier control circuit 101 irradiates the beam irradiation device 2 with the irradiation spot L1 shown in FIG. 20, and then interrupts the melting process of the powder material 32. Then, as shown in FIGS. 21 and 22, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to scan the irradiation position L2 of the electron beam 15 within the range of the first heating region H1 set in the process of step S27, thereby preheating the powder material 32.

[0083] Furthermore, when the preliminary heating process is completed, as shown in Fig. 22, the polarization amplifier control circuit 101 selects the irradiation position L2 of the electron beam 15 as the coordinates of the next irradiation point from the irradiation spot L1 where the melting process was interrupted as shown in Fig. 20. Then, as shown in Fig. 23, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to irradiate the electron beam 15 onto the predetermined irradiation spot L1.

[0084] In this way, the timing of preheating during the melting process is the same for multiple objects 38A, 38B, and 38C of different sizes. This makes it possible to suppress the temperature difference during melting of the powder material 32 between the small objects 38A and 38C and the large object 38B. As a result, it is possible to obtain the same quality for all of the multiple objects 38A, 38B, and 38C of different sizes.

[0085] The above-described process is continued until the powder material 32 of all of the objects 38A, 38B, and 38C is melted. In the above example, the number n of irradiation points of the electron beam 15 and the elapsed time t1 are retained when the irradiation spot L1 is switched from the first object 38A to the second object 38B, but this is not limiting. For example, when the irradiation spot L1 is switched from the first object 38A to the second object 38B, the number n of irradiation points may be set to 0, and the elapsed time t1 may be set to the time when the second object 38B starts to melt, as shown in step S23 above.

[0086] 2-3. Second operation example of this sintering process Next, a second operation example of the main sintering step will be described with reference to Figures 24 to 34. Figures 24A to 24C are explanatory views showing a second operation example (local heating) of the preheating operation during the main sintering step.

[0087] As shown in FIG. 24A, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104 to irradiate the powder material 32 with the electron beam 15. As a result, the powder material 32 is melted by the irradiation of the electron beam 15. When a predetermined timing is reached during the sintering process, the PC 104 outputs a control signal to the polarization amplifier control circuit 101 to interrupt the process of melting the powder material 32 with the electron beam 15. Note that the predetermined timing may be, for example, when the elapsed time t of the main sintering process or the number n of irradiation points of the electron beam 15 reaches a predetermined pre-heating start threshold t heating or n heating When it reaches

[0088] Next, as shown in FIG. 24B, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to preheat the powder material 32. At this time, the polarization amplifier control circuit 101 defocuses the electron beam 15 using an objective lens or the like provided in the beam irradiation device 2. Here, in the second operation example, i.e., in local heating, the second heating region H2 is set only to the first object 38A being melted and the periphery of the first object 38A, as shown in FIG. 24B. Then, when the preheating process shown in FIG. 24B is completed, the polarization amplifier control circuit 101 controls the beam irradiation device 2 based on a control signal from the PC 104 to irradiate the powder material 32 with the electron beam 15, as shown in FIG. 24C. Then, the powder material 32 is melted again, and the main sintering process is resumed.

[0089] Furthermore, if the PC 104 determines in step S25 of FIG. 5 that the acquired heating process is local heating, the PC 104 sets all of the objects 38A, 38B, and 38C to be melted in the next set after heating and their surroundings as the second heating region H2 of the preheating region, and outputs a control signal to the polarization amplifier control circuit 101 (step S26). As a result, as shown in FIG. 25, when the number of irradiation points n or the elapsed time t reaches the preheating start threshold, the polarization amplifier control circuit 101 suspends the melting process of the powder material 32 after irradiation by the beam irradiation device 2. Then, as shown in FIG. 26, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to scan the irradiation position L2 of the electron beam 15 within the range of the second heating region H2 set in step S26. As a result, the powder material 32 is preheated again.

[0090] Then, when the specified time has elapsed, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to end the preheating (step S29).

[0091] When the processing of step S29 is completed, the PC 104 sets the value of the number of irradiation points n stored in the memory unit 105 to "0." Alternatively, the PC 104 stores the time when the preheating is completed as the elapsed time t1 in the memory unit 105 (step S30). Then, when the processing of step S30 is completed, the processing of steps S31 and S32, i.e., the melting process of the powder material 32, is resumed. In step S31, as shown in FIG. 27, the polarization amplifier control circuit 101 selects the irradiation position L2 of the electron beam 15 as the coordinates of the next irradiation point from the irradiation spot L1 where the melting process was interrupted as shown in FIG. 25. Then, as shown in FIG. 28, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to perform the melting process of the powder material 32 again until the number of irradiation points n or the elapsed time t reaches the preheating start threshold.

[0092] Here, if the irradiation spot L1 moves from the first object 38A to the second object 38B before the number of irradiation points n or the elapsed time t reaches the pre-heating start threshold, the PC 104 sets the range of the pre-heating area to the second heating area H2 as shown in Fig. 29. That is, not only the first object 38A currently undergoing the melting process of the powder material 32, but also the second object 38B to be subjected to the melting process next is set to the second heating area H2.

[0093] 30 to 32, when the melting treatment of the powder material 32 of the first object 38A is completed, the PC 104 switches to the melting treatment of the powder material 32 of the second object 38B. Here, as shown in step S22 described above, the number n of irradiation points of the electron beam 15 and the elapsed time t1 are taken over from the first object 38A.

[0094] Furthermore, when the melting process of the powder material 32 of the first object 38A is completed and the number of irradiation points n or the elapsed time t reaches the pre-heating start threshold during the melting process of the powder material 32 of the second object 38B, the range of the second heating area H2 of the pre-heating area set by PC104 becomes only the second object 38B, as shown in Figure 33.

[0095] Then, when the processing of step S29 is completed, the PC 104 sets the value of the number of irradiation points n stored in the memory unit 105 to "0." Alternatively, the PC 104 stores the time when the preheating is completed as the elapsed time t1 in the memory unit 105 (step S30). Then, when the processing of step S30 is completed, the processing of steps S31 and S32, i.e., the melting process of the powder material 32, is resumed. In step S31, as shown in FIG. 34, the polarization amplifier control circuit 101 selects the irradiation position L2 of the electron beam 15 as the coordinates of the next irradiation point from the irradiation spot L1 shown in FIG. 33 where the melting process was interrupted. Then, as shown in FIG. 34, the polarization amplifier control circuit 101 controls the beam irradiation device 2 to perform the melting process of the powder material 32 again until the number of irradiation points n or the elapsed time t reaches the preheating start threshold.

[0096] The above-described process is continued until the powder material 32 of all of the shaped objects 38A, 38B, and 38C is melted.

[0097] In this second operation example, as in the first operation example, it is possible to suppress the variation in temperature between the powder material 32 that melts first and the powder material 32 that melts last in one object. Furthermore, it is possible to suppress the temperature difference when the powder material 32 melts between the small objects 38A and 38C and the large object 38B.

[0098] According to this second operation example, the second heating area H2 can be made smaller than the first heating area H1, which is the preheating area in the first operation example. This makes it possible to shorten the time required for the preheating process performed during the melting process compared to the first operation example. As a result, it is possible to shorten the throughput of the modeling process in the 3D additive manufacturing apparatus 1 compared to the first operation example.

[0099] When forming the objects 38A, 38B, and 38C, the first and second operation examples described above may be combined. That is, the first operation example may be performed on one layer among the multiple layers, and the second operation example may be performed on a different layer among the multiple layers.

[0100] The present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made without departing from the spirit of the invention as set forth in the claims.

[0101] The first irradiation range H1 and the second irradiation range H2 of the electron beam 15 when preheating is performed may be set by the PC 104, which is the control unit, or may be set by a user and input to the PC 104 and the storage unit 105 via an input unit connected to the PC 104 and the storage unit 105. Furthermore, the preheating start threshold t heating or n heating The irradiation range may be set by the PC 104 based on the modeling data. Alternatively, the user may set the irradiation range and input the set irradiation range to the PC 104 or the storage unit 105 via an input unit connected to the PC 104 and the storage unit 105.

[0102] For example, in the above-described embodiment, an example has been described in which metal powder such as titanium, aluminum, or iron is used as the powder material, but the present invention is not limited thereto, and resin or the like may also be used as the powder material. Furthermore, an example has been described in which a beam irradiation device that irradiates an electron beam is used as the irradiation device, but the present invention is not limited thereto. For example, a laser irradiation device that irradiates a laser as a primary beam may also be used as the irradiation device.

[0103] Furthermore, some or all of the above-described components, functions, processing units, etc. may be implemented in hardware, for example, by designing an integrated circuit. Furthermore, the above-described components, functions, etc. may be implemented in software by a processor interpreting and executing a program that implements each function. Information such as the programs, tables, and files that implement each function can be stored in a storage device such as a memory, a hard disk, or an SSD (Solid State Drive), or in a storage medium such as an IC card, SD card, or DVD.

[0104] In this specification, the words "parallel" and "orthogonal" are used, but these do not mean only "parallel" and "orthogonal" in the strict sense, but also include "parallel" and "orthogonal" and may also mean a "substantially parallel" or "substantially orthogonal" state within a range in which the functions can be exerted. [Explanation of symbols]

[0105] 1...3D additive manufacturing device, 2...beam irradiation device, 3...vacuum chamber, 15...electron beam, 16...powder supply device, 16a...hopper, 16b...powder dropper, 16c...squeegee, 16d...blade, 18...build table, 20...build box, 21...recovery box, 22...build plate, 24...inner base, 26...plate moving device, 32...powder material, 38, 38A, 38B, 38C...model, 38C...support unit, 42...camera, 44...shutter, 46...detection unit, 101...polarization amplifier control circuit, 102...digital conversion circuit (ADC), 103...preamplifier (Pre-AMP) 104...personal computer (PC, control unit), 105...memory unit, H1...first heating area, H2...second heating area, L1: Irradiation spot, L2: Irradiation position

Claims

1. In a three-dimensional additive manufacturing apparatus for manufacturing a model, A shaping plate and a powder supplying device that supplies powder material to the build plate to form a powder layer; an irradiation device that irradiates the powder layer with a primary beam; a control unit that controls the irradiation device, When a predetermined timing is reached during melting of the powder material, the control unit controls the irradiation device to interrupt the melting process of the powder material and perform a preheating process of preheating the powder material. 3D additive manufacturing device.

2. a storage unit that stores a preheating start threshold value that is a timing for starting preheating, and the number of irradiation points of the primary beam or the elapsed time during the melting process of the powder material; The control unit performs the preheating process when the number of irradiation points of the primary beam or the elapsed time reaches the preheating start threshold during the melting process of the powder material. The three-dimensional additive manufacturing apparatus according to claim 1 .

3. The control unit resets the number of irradiation points or the elapsed time of the primary beam after the preliminary heating process is performed. The three-dimensional additive manufacturing apparatus according to claim 2 .

4. In the case of forming the first object and the second object, When the melting process of the powder material of the first object is completed, the control unit switches to the melting process of the powder material of the second object and takes over the number of irradiation points of the primary beam or the elapsed time from the first object. The three-dimensional additive manufacturing apparatus according to claim 3 .

5. The control unit sets a heating region to be irradiated with the primary beam to cover the entire meltable area when the preliminary heating process is performed. The three-dimensional additive manufacturing apparatus according to claim 1 .

6. In the case of forming a plurality of the above-mentioned objects, When performing the preliminary heating process, the control unit sets a heating region to be irradiated with the primary beam to a modeling surface of at least one of the plurality of models that is undergoing a melting process. The three-dimensional additive manufacturing apparatus according to claim 1 .

7. When performing the preheating process, the control unit sets the heating region to be irradiated with the primary beam to the modeling surface of the object to be melted after the preheating process, in addition to the modeling surface of the object currently being melted among the plurality of objects. The three-dimensional additive manufacturing apparatus according to claim 6.

8. providing a powder material; a process of irradiating the powder material with a primary beam to melt the powder material; When a predetermined timing is reached during melting of the powder material, the melting process of the powder material is interrupted and a preheating process is performed to preheat the powder material. A method for controlling a three-dimensional additive manufacturing device.

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