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

Abstract

To provide a three dimensional lamination shaping device and a three dimensional lamination shaping method capable of suppressing deterioration of quality of a three dimensional structure to be shaped.SOLUTION: The three dimensional laminating and shaping apparatus includes a stage, a beam emitting unit, a beam deflecting unit, and a control unit. A powder layer made of a powder material is spread on the stage. The beam emitting unit emits a beam toward the powder layer spread on the stage. The beam deflector deflects the beam emitted from the beam emitter. The control unit controls the beam emission unit and the beam deflection unit. Before a region corresponding to a part to be molded in the powder layer spread on the stage is melted by the melting beam, the control unit controls the beam emission unit and the beam deflection unit to perform pre-melting preheating in which the region corresponding to the part is heated by the heating beam.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a three-dimensional additive manufacturing apparatus and a three-dimensional additive manufacturing method. [Background technology]

[0002] In recent years, three-dimensional additive manufacturing (3D AM) devices have become known that build three-dimensional objects by stacking layers of solidified powder material. The 3D AM device irradiates a beam onto powder material spread on a stage, melting and solidifying the powder material.

[0003] Patent Document 1 describes a three-dimensional additive manufacturing apparatus. The method for forming a molded object using the three-dimensional additive manufacturing apparatus described in Patent Document 1 includes a mold preparation step, a stage heating step, a powder spreading step, a first preheating step, a main melting step, a second preheating step, and a molded object removal step. In the first preheating step, a beam irradiation device irradiates an electron beam onto powder on the stage to pre-sinter the powder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-106332 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the first preheating step of the 3D additive manufacturing device described in Patent Document 1, the entire powder on the stage is pre-sintered by scanning an electron beam over the entire powder on the stage. Therefore, when manufacturing multiple parts on the stage, heat dissipation from the powder surface progresses as the parts are manufactured, causing the powder surface temperature to decrease. If the powder surface temperature decreases, defects such as cracks will occur in the manufactured object when it solidifies after melting, reducing the quality of the manufactured object.

[0006] In consideration of the above problems, an object of the present invention is to provide a three-dimensional additive manufacturing device and a three-dimensional additive manufacturing method that can suppress deterioration in the quality of the three-dimensional structure to be manufactured. [Means for solving the problem]

[0007] In order to solve the above problems and achieve the object of the present invention, a three-dimensional additive manufacturing apparatus embodying one aspect of the present invention includes a stage, a beam emission unit, a beam deflection unit, and a control unit. A powder layer made of powder material is spread on the stage. The beam emission unit emits a beam toward the powder layer spread on the stage. The beam deflection unit deflects the beam emitted from the beam emission unit. The control unit controls the beam emission unit and the beam deflection unit. Before melting an area of ​​the powder layer spread on the stage corresponding to a part to be manufactured with a melting beam, the control unit controls the beam emission unit and the beam deflection unit to perform pre-melting preheating, in which the area corresponding to the part is heated with a heating beam.

[0008] A three-dimensional additive manufacturing method embodying one aspect of the present invention is a method performed in a melting step of melting an area of ​​a powder layer spread on a stage that corresponds to a part to be manufactured. In the melting step, a control unit controls a beam emission unit and a beam deflection unit to perform pre-melting preheating by heating the area corresponding to the part with a heating beam before melting the area corresponding to the part with a melting beam. [Effects of the Invention]

[0009] According to the three-dimensional additive manufacturing device and three-dimensional additive manufacturing method configured as described above, deterioration in the quality of the three-dimensional structure to be manufactured can be suppressed. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram showing a three-dimensional additive manufacturing apparatus according to an embodiment. FIG. [Figure 2] FIG. 2 is a block diagram showing a functional configuration of a beam position control unit of the three-dimensional additive manufacturing apparatus according to one embodiment. [Figure 3]FIG. 1 is a plan view showing a state in which a plurality of parts are being formed on a stage of a three-dimensional additive manufacturing apparatus according to one embodiment. [Figure 4] FIG. 10 is a diagram illustrating a first main melting pattern showing a first example of main melting by the three-dimensional additive manufacturing device according to one embodiment. [Figure 5] 10 is a table showing an example of settings of a melting beam and a preheating beam in a first main melting pattern. [Figure 6] FIG. 10 is a diagram illustrating a second main melting pattern showing a second example of main melting by the three-dimensional additive manufacturing device according to one embodiment. [Figure 7] FIG. 10 is a diagram illustrating a second main melting pattern showing a second example of main melting by the three-dimensional additive manufacturing device according to one embodiment. [Figure 8] FIG. 10 is a diagram illustrating a third main melting pattern showing a third example of main melting by the three-dimensional additive manufacturing device according to one embodiment. [Figure 9] FIG. 10 is a diagram illustrating a third main melting pattern showing a third example of main melting by the three-dimensional additive manufacturing device according to one embodiment. [Figure 10] 10 is a table showing examples of settings of the melting beam and the preheating beam in the second and third main melting patterns. [Figure 11] FIG. 10 is a diagram showing the temperature distribution during melting when preheating before melting of the second and third main melting patterns is not performed. [Figure 12] FIG. 10 is a diagram showing the temperature distribution during melting when main melting (with preheating before melting) is performed using the second and third main melting patterns. [Figure 13] FIG. 10 is a diagram illustrating a fourth main melting pattern showing a fourth example of main melting by the three-dimensional additive manufacturing device according to one embodiment. [Figure 14] 10 is a table showing an example of settings of a melting beam and a preheating beam in a fourth main melting pattern. [Figure 15] FIG. 10 is a diagram showing the temperature distribution during melting in the case where preheating before melting of the fourth main melting pattern is not performed. [Figure 16]FIG. 10 is a diagram showing the temperature distribution during melting when main melting (with preheating before melting) is performed using the fourth main melting pattern. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, one embodiment of a three-dimensional additive manufacturing device and a three-dimensional additive manufacturing method of the present invention will be described with reference to Figures 1 to 16. Note that common members in the figures are denoted by the same reference numerals.

[0012] [3D additive manufacturing equipment] First, the configuration of a three-dimensional additive manufacturing apparatus according to one embodiment will be described with reference to FIG. FIG. 1 is an explanatory diagram schematically illustrating a three-dimensional additive manufacturing apparatus according to one embodiment.

[0013] The 3D additive manufacturing apparatus 1 shown in Fig. 1 is an apparatus that irradiates a powder material with an electron beam to melt the powder material, and then stacks images of the solidified powder material to form a three-dimensional object. As shown in Fig. 1, the 3D additive manufacturing apparatus 1 includes an electron gun 2 that emits an electron beam L1, a lens 4, a powder material storage chamber 5, a stage 6, a powder stacking arm 7, and a beam deflection unit 10. The electron gun 2 corresponds to the beam emission unit of the present invention.

[0014] The electron gun 2, deflection amplifier 3, lens 4, powder material storage 5, stage 6, and powder deposition arm 7 are arranged in a fabrication chamber (not shown). A vacuum pump is connected to the fabrication chamber. The vacuum pump removes gas from the interior of the fabrication chamber, thereby evacuating the interior space of the fabrication chamber.

[0015] The electron gun 2 includes an emitter 21, an extraction electrode 22, and an acceleration electrode 23. The emitter 21 and the acceleration electrode 23 are connected to an acceleration power supply 24. The extraction electrode 22 is connected to an extraction potential generator (not shown). The extraction potential generator applies an extraction potential to the extraction electrode 22. When the extraction potential is applied, the extraction electrode 22 extracts electrons from the emitter 21.

[0016] The acceleration electrode 23 generates an electron beam L1 by accelerating the electrons extracted from the emitter 21 using an acceleration potential applied by an acceleration power supply 24. The acceleration electrode 23 directs the generated electron beam L1 toward the lens 4 and the deflection amplifier 3.

[0017] A deflection amplifier 3 (to be described later) of the beam deflection unit 10 is disposed between the electron gun 2 and the stage 6. The detailed configuration of the beam deflection unit 10 will be described later with reference to FIG.

[0018] The lens 4 is disposed between the deflection amplifier 3 and the electron gun 2. The lens 4 focuses the electron beam L1 emitted from the electron gun 2 by electromagnetic action. The lens 4 then forms an image of the focal point of the electron beam L1 on the stage 6.

[0019] The stage 6 is formed in a substantially flat plate shape. The stage 6 is supported by a driving device (not shown) so as to be movable in the vertical direction. A powder material M1 is supplied to one side of the stage 6 from a powder material storage 5. Examples of the powder material M1 include metals such as titanium, aluminum, and iron, as well as solid materials such as ceramics and organic resins.

[0020] In addition, a powder deposition arm 7 is disposed near the stage 6. The powder deposition arm 7 is supported by a movement mechanism (not shown) so as to be movable horizontally on one surface of the stage 6. As the powder deposition arm 7 moves horizontally on one surface of the stage 6, the powder material M1 is spread over one surface of the stage 6 to a predetermined height (for example, the diameter of one grain of the powder material M1).

[0021] The electron beam L1 is irradiated onto a layer (powder layer) of powder material M1 spread on the stage 6, causing the powder material M1 to melt and then solidify. After the powder material M1 has melted and solidified, the stage 6 is lowered vertically by one layer by a driving device (not shown). Then, the powder material storage 5 supplies new powder material M1, and the powder layering arm 7 spreads the powder material M1 to a predetermined height.

[0022] [Beam deflection section] Next, the configuration of the beam deflection unit 10 will be described with reference to FIG. FIG. 2 is a block diagram showing the functional configuration of the beam deflection unit 10. As shown in FIG.

[0023] 2, the beam deflection unit 10 has a deflection amplifier 3 and a coordinate conversion correction circuit 8. The deflection amplifier 3 is disposed between the electron gun 2 and the stage 6. The deflection amplifier 3 deflects the electron beam L1 emitted from the electron gun 2 to a predetermined position on the stage 6.

[0024] The coordinate conversion correction circuit 8 controls the operation of the deflection amplifier 3. The coordinate conversion correction circuit 8 is connected to a control device 30. The control device 30 can be, for example, a PC (personal computer). The control device 30 transmits a position command signal and an irradiation time command signal to the coordinate conversion correction circuit 8. The position command signal is a signal indicating a coordinate position that indicates the irradiation position of the electron beam L1. The irradiation time command signal is a signal that indicates the irradiation time of the electron beam L1.

[0025] The coordinate conversion correction circuit 8 generates an amplifier control signal corresponding to the commanded coordinate position and irradiation time based on the received position command signal and irradiation time command signal. The coordinate conversion correction circuit 8 operates the deflection amplifier 3 based on the generated amplifier control signal. As a result, the deflection amplifier 3 deflects the electron beam L1 emitted from the electron gun 2 to the commanded coordinate position of the stage 6.

[0026] [Multiple part printing] Next, a case where the three-dimensional additive manufacturing apparatus 1 manufactures a plurality of parts on the stage 6 will be described with reference to FIG. FIG. 3 is a plan view showing a state in which a plurality of parts are being manufactured on the stage 6 of the three-dimensional additive manufacturing apparatus 1. As shown in FIG.

[0027] As shown in FIG. 3, the three-dimensional additive manufacturing apparatus 1 can manufacture a plurality of parts ((manufactured objects)) 40 on a stage 6. The plurality of parts 40 may have the same shape, or may have different shapes. The positions at which the plurality of parts 40 are manufactured are dispersed at an appropriate distance. The positions at which the plurality of parts 40 are manufactured may also be aligned in a predetermined direction.

[0028] When manufacturing multiple parts 40 on the stage 6, the 3D additive manufacturing apparatus 1 performs a manufacturing preparation step, a stage heating step, a powder spreading step, a first pre-heating step, a main melting step, a second pre-heating step, and a molded object removal step. The 3D additive manufacturing apparatus 1 repeats the powder spreading step, the first pre-heating step, the main melting step, and the second pre-heating step until manufacturing of multiple parts 40 is completed.

[0029] (Modeling preparation process) In the modeling preparation step, the 3D additive manufacturing apparatus 1 acquires modeling data for forming a model. The modeling data is supplied to the control device 30 via a communication line, for example, and stored in the storage unit 34 of the control device 30. Alternatively, the modeling data may be recorded on a recording medium readable by the control device 30 and supplied to the control device 30 via the recording medium.

[0030] When multiple parts 40 are to be formed on the stage 6, the control device 30 calculates the formation position of each part 40. Note that the formation position of each part 40 may be acquired together with the formation data.

[0031] (Stage heating process) In the stage heating step, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to irradiate the electron beam L1 onto the upper surface of the stage 6. As a result, the stage 6 is heated.

[0032] (Powder spreading process) In the powder spreading process, the stage 6 is lowered vertically by one layer by a driving device (not shown). Next, the powder material storage 5 (see FIG. 1) supplies powder material M1 to the upper surface of the stage 6. Then, the powder layering arm 7 (see FIG. 1) moves horizontally above the stage 6 to spread the powder material M1 on the stage 6 to a predetermined height.

[0033] (First preheating step) In the first pre-heating step, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to irradiate the electron beam L1 onto the powder material M on the stage 6. At this time, the control device 30 causes the electron beam L1 to scan the entire surface of the powder material M, thereby heating (pre-sintering) the entire surface of the powder material M. The first pre-heating step is also called a powder heating step.

[0034] (Main melting process) In the main melting process, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to perform pre-melting preheating and main melting for each part 40. In the pre-melting preheating, the electron beam L1 is irradiated onto at least the powder material M (hereinafter referred to as the "melting target portion") corresponding to the part 40, thereby heating the melting target portion.

[0035] After the pre-melting preheating, the control device 30 irradiates the melting target portion with the electron beam L1 to melt the melting target portion (full melting). The melting target portion melted by irradiation with the electron beam L1 solidifies after the electron beam L1 has passed. When the pre-melting preheating and full melting have been completed for the melting target portions of all parts 40, the fabrication of one layer of all parts 40 is complete.

[0036] (Second preheating step) In the second preheating step, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to irradiate the electron beam L1 onto the multiple parts 40 on the stage 6. This raises the temperature of the multiple parts 40 in preparation for the formation of the next layer. The second preheating step is also called an afterheating step.

[0037] (Model removal process) In the model removal step, the three-dimensional additive manufacturing apparatus 1 removes excess parts attached to the model and peels off the model from the stage 6 using a post-processing unit (not shown).

[0038] [First melting pattern] Next, a first main melting pattern showing a first example of main melting performed by the control device 30 in the main melting step will be described with reference to FIG. FIG. 4 is a diagram illustrating the first melting pattern.

[0039] 4 are, for example, points at which powder material M is melted when part 40 is manufactured. The points at which electron beam L1 is irradiated to manufacture part 40 are aligned, for example, in a first direction X that is parallel to the horizontal direction and a second direction Y that is parallel to the horizontal direction and approximately perpendicular to first direction X. Note that the points at which electron beam L1 is irradiated do not have to be aligned along two directions that intersect approximately perpendicularly, and may be aligned, for example, along two directions that intersect at any angle.

[0040] 4, the first direction X is the left-right direction, and the second direction Y is the up-down direction. Hereinafter, the lines along the first direction X will be referred to as rows, and the lines along the second direction Y will be referred to as columns. The points irradiated with the electron beam L1 are arranged, for example, in 3 rows and 6 columns.

[0041] Hereinafter, the point before pre-melting preheating is referred to as the "unirradiated point." In the first main melting pattern, the control device 30 controls the electron gun 2 to set the electron beam L1 as the heating beam. Then, the control device 30 controls the beam deflection unit 10 to move the focus of the heating beam to the unirradiated point in the upper right corner of the part 40 (Step 1).

[0042] The step of setting the heating beam and the step of moving the focus of the electron beam L1 may be performed simultaneously. The step of moving the focus of the electron beam L1 may be performed before the step of setting the heating beam. The setting items for the heating beam include, for example, the beam diameter. The diameter of the heating beam is set to be larger than the diameter of the melting beam described below and to a size that does not melt unirradiated points.

[0043] Next, the control device 30 controls the beam deflection unit 10 to perform pre-melting preheating. That is, the control device 30 irradiates the heating beam to all unirradiated points on the part 40 (step 2). The control device 30 heats all unirradiated points on the part 40 by irradiating the heating beam, for example, starting from the unirradiated point in the upper right corner and irradiating adjacent points in order. As a result, the area including all unirradiated points on the part 40 becomes the area where pre-melting preheating has been performed. Hereinafter, the points that have been pre-heated before melting will be referred to as "heated points."

[0044] Next, the control device 30 controls the electron gun 2 to change the electron beam L1 to a melting beam (step 3). In this example, the unirradiated point in the lower left corner is heated last. The control device 30 changes the heating beam to a melting beam at a position where the heated point in the lower left corner is the focal point. The setting items for the melting beam include, for example, the beam diameter. For example, the diameter of the melting beam is smaller than the diameter of the heating beam.

[0045] Next, the control device 30 starts irradiating the melting beam from the heated point at the lower right corner (Step 4).Then, the control device 30 controls the beam deflection unit 10 to irradiate the melting beam from the heated point at the lower right corner to adjacent points in turn, thereby melting all heated points on the part 40 (Step 5).

[0046] In this way, in the first main melting pattern, all unirradiated points of the part 40 are preheated (pre-melting preheating) before being melted. This reduces the temperature difference between the melted points and their surroundings. As a result, defects such as cracks are less likely to occur in the molded object when it solidifies after melting, and deterioration in the quality of the molded object can be suppressed or prevented.

[0047] In the first main melting pattern described above, melting started from the heated point at the bottom right corner where pre-heating before melting was last performed. However, the melting start point may also be the point where pre-heating before melting started (the heated point at the top right corner).

[0048] The timing at which the diameter of the electron beam L1 is changed to the melting beam diameter may be before moving to the point where pre-melting preheating starts, after moving to the point where pre-melting preheating starts, or during moving to the point where pre-melting preheating starts. When the diameter of the electron beam L1 is changed during movement, melting can start earlier than in other cases, and the time required for main melting can be shortened.

[0049] [Beam settings for the first melting pattern] Next, the settings of the melting beam and the heating beam in the first main melting pattern will be described with reference to FIG. FIG. 5 is a table showing an example of settings of the melting beam and the heating beam in the first main melting pattern.

[0050] As shown in Fig. 5, the setting items of the melting beam and the heating beam include, for example, the beam current value, beam diameter, scan pitch, line spacing, scan speed, and acceleration voltage value. In the first melting pattern, all setting items of the heating beam are variables that can be set as appropriate. Also, the beam current value, beam diameter, scan speed, and acceleration voltage value of the melting beam are variables that can be set as appropriate.

[0051] As the beam current value increases, the number of electrons per unit time in the electron beam increases, and the energy of the electron beam increases. In this example, the beam current value of the melting beam is set to a value smaller than the beam current value of the heating beam. However, the beam current value of the melting beam in this example may be equal to or greater than the beam current value of the heating beam.

[0052] As the beam diameter increases, the number of electrons per unit area in the electron beam decreases, and the energy of the electron beam decreases. In this example, the beam diameter of the melting beam is set to a value smaller than the beam diameter of the heating beam.

[0053] The scan pitch is the distance between adjacent scan points. In this example, the scan pitch of the heating beam is set to a value larger than the scan pitch of the melting beam.

[0054] The line spacing is the distance between the centers of the electron beams on adjacent lines in the second direction Y. The line spacing of the melting beam is determined according to the spacing in the second direction Y between multiple unirradiated points on the part 40. The line spacing of the heating beam in this example is larger than the line spacing of the melting beam. Note that the line spacing of the heating beam in this example can be set appropriately according to the beam diameter.

[0055] As the scanning speed increases, the irradiation dose of the electron beam decreases. In this example, the scanning speed of the melting beam is set to a value slower than the scanning speed of the heating beam. Since the heating beam is a beam that heats the powder material M in the area corresponding to the part 40, the scanning speed of the heating beam is set to be faster than that of the melting beam.

[0056] The acceleration voltage value determines the energy of the electron beam. In this example, the acceleration voltage values ​​of the melting beam and the heating beam are set to the same value. However, the acceleration voltage values ​​of the melting beam and the heating beam in this example may be different values.

[0057] In the setting example shown in Figure 5, the beam current value, beam diameter, scan pitch, and scan speed values ​​of the melting beam are set smaller than the beam current value, beam diameter, scan pitch, and scan speed values ​​of the heating beam. However, the melting beam is not limited to having all variables smaller than the variables of the heating beam, and the variable values ​​can be set appropriately as long as the powder material M can be melted. Furthermore, the heating beam is not limited to having all variables larger than the variables of the melting beam, and the variable values ​​can be set appropriately as long as the powder material M can be heated without melting it.

[0058] The setting items that determine the energy and irradiation amount of the heating beam and the melting beam are not limited to those shown in FIG.

[0059] [Second melting pattern] Next, a second main melting pattern showing a second example of main melting performed by the control device 30 in the main melting step will be described with reference to FIGS. 6 and 7 are diagrams illustrating the second main melting pattern.

[0060] 6 and 7 are points at which the powder material M is melted when forming the part 40. The points at which the electron beam L1 is irradiated are arranged in, for example, 2 rows and 16 columns.

[0061] As shown in Figure 6, in the second melting pattern, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to set the electron beam L1 as a heating beam at a position where the focus is on the unirradiated point at the right end of the top row (line) of the part 40 (Step 1).

[0062] Next, the control device 30 controls the beam deflection unit 10 to perform pre-melting pre-heating on the top row of the part 40. That is, the control device 30 irradiates the heating beam onto the multiple unirradiated points on the top row (step 2). As a result, the multiple unirradiated points on the top row become heated points, and the area including the multiple heated points becomes an area where pre-melting pre-heating has been performed.

[0063] Next, the control device 30 controls the electron gun 2 to change the heating beam to a melting beam at a position where the heated point at the left end of the top row is the focal point (step 3). In this example, the leftmost unirradiated point in the area where pre-melting preheating was performed is heated last. The control device 30 changes the heating beam to a melting beam at a position where the heated point that was last heated is the focal point.

[0064] 7, the control device 30 starts irradiating the melting beam from the heated point at the left end of the top row (Step 4).Then, the control device 30 controls the beam deflection unit 10 to irradiate the melting beam sequentially from the heated point at the left end to the heated point at the right end of the top row, thereby melting the heated points at the top row (Step 5).

[0065] Next, control device 30 controls electron gun 2 to change the melting beam to a heating beam. Then, control device 30 controls beam deflection unit 10 to move the focal point of the heating beam to the unirradiated point at the right end of the second row from the top (Step 6). Thereafter, control device 30 performs Steps 2 to 5 on the multiple unirradiated points in the second row from the top.

[0066] In this way, in the second main melting pattern, preheating (preheating before melting) and melting are performed on each of the multiple unirradiated points on the part 40, one row at a time. This reduces the temperature difference between the melted point and its surroundings. As a result, defects such as cracks are less likely to occur in the molded object when it solidifies after melting, and deterioration in the quality of the molded object can be suppressed or prevented.

[0067] [Third melting pattern] Next, a third main melting pattern showing a third example of main melting performed by the control device 30 in the main melting step will be described with reference to FIGS. 8 and 9 are diagrams illustrating the third main melting pattern.

[0068] 8 and 9 are points at which the powder material M is melted when forming the part 40. The points at which the electron beam L1 is irradiated are arranged in, for example, 2 rows and 16 columns.

[0069] As shown in Figure 8, in the third melting pattern, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to set the electron beam L1 as a heating beam at a position where the focal point is the unirradiated point at the right end of the top row (line) of the part 40 (Step 1).

[0070] Next, the control device 30 controls the beam deflection unit 10 to perform pre-melting pre-heating on the top row of the part 40. That is, the control device 30 irradiates the heating beam onto the multiple unirradiated points on the top row (step 2). As a result, the multiple unirradiated points on the top row become heated points, and the area including the multiple heated points becomes an area where pre-melting pre-heating has been performed.

[0071] After irradiating the heating beam to the plurality of unirradiated points in the top row, the control device 30 controls the beam deflection unit 10 to return the focal point of the electron beam L1 to the heated point at the right end of the top row (Step 3).Then, the control device 30 controls the electron gun 2 to change the heating beam to a melting beam.

[0072] 9, the control device 30 starts irradiating the melting beam from the heated point at the right end of the top row (Step 4).Then, the control device 30 controls the beam deflection unit 10 to irradiate the melting beam sequentially from the heated point at the right end of the top row to the heated point at the left end, thereby melting the heated points in the top row (Step 5).

[0073] Next, control device 30 controls electron gun 2 to change the melting beam to a heating beam. Then, control device 30 controls beam deflection unit 10 to move the focal point of the heating beam to the leftmost unirradiated point in the second row from the top (Step 6). Thereafter, control device 30 performs Steps 2 to 5 on the multiple unirradiated points in the second row from the top.

[0074] In this way, in the third main fusing pattern, similar to the second main fusing pattern, preheating (preheating before melting) and melting are performed on multiple unirradiated points on part 40, row by row. This reduces the temperature difference between the melted point and its surroundings. As a result, defects such as cracks are less likely to occur in the molded object when it solidifies after melting, and deterioration in the quality of the molded object can be suppressed or prevented.

[0075] Furthermore, in the third main fusing pattern, the directions of pre-heating and main fusing are reversed in adjacent rows (lines). This reduces the temperature difference between one end and the other end of part 40 in first direction X (the direction parallel to the rows). As a result, deterioration in the quality of the molded object can be suppressed or prevented more effectively than in the second main fusing pattern.

[0076] [Beam settings for the second and third melting patterns] Next, the settings of the melting beam and the heating beam in the second and third main melting patterns will be described with reference to FIG. FIG. 10 is a table showing examples of settings of the melting beam and the heating beam in the second and third main melting patterns.

[0077] 10, the setting items of the melting beam and the heating beam include, for example, the beam current value, beam diameter, scan pitch, line spacing, scan speed, and acceleration voltage value. In the second and third melting patterns, the beam current value, beam diameter, scan pitch, scan speed, and acceleration voltage value of the heating beam are variables that can be set as appropriate. Also, the beam current value, beam diameter, scan speed, and acceleration voltage value of the melting beam are variables that can be set as appropriate.

[0078] In the second and third melting patterns, the line spacing of the melting beams and heating beams is determined according to the spacing in the second direction Y between the multiple unirradiated points on the part 40. Therefore, the line spacing of the melting beams and heating beams in the second and third melting patterns is the same value.

[0079] [Temperature distribution during melting] Next, the temperature distribution of the powder material M when pre-heating before melting is not performed and when pre-heating before melting is performed will be described with reference to FIGS. Fig. 11 shows the temperature distribution during melting when preheating before melting is not performed for the second and third main melting patterns, and Fig. 12 shows the temperature distribution during melting when main melting (with preheating before melting) is performed for the second and third main melting patterns.

[0080] 11 and 12, the vertical axis represents the temperature of the powder material M. The vertical axis represents the distance in the first direction X (the direction parallel to the rows).

[0081] The temperature distribution shown in Figure 11 is the temperature distribution when the entire surface of the powder material M is heated in the first preheating step, and then main melting is performed without performing preheating before melting as shown in the second and third main melting patterns. As shown in Figure 11, the temperature at the melting point is high, but the temperature at a point d (µm) away from the center of the melting point in the second direction Y is significantly different from the temperature at the melting point (d > radius of the melting point). Therefore, defects such as cracks are likely to occur in the molded object when it solidifies after melting.

[0082] The temperature distribution shown in Figure 12 shows the temperature distribution during main melting after pre-melting preheating as shown in the second and third main melting patterns. As shown in Figure 12, a point d (μm) away from the center of the melting point in the second direction Y is included in the area where pre-melting preheating was performed. Therefore, the temperature at the point d (μm) away from the center of the melting point in the second direction Y is only slightly different from the temperature at the melting point. Therefore, defects such as cracks are less likely to occur in the molded object when it solidifies after melting.

[0083] [Fourth melting pattern] Next, a fourth main melting pattern showing a fourth example of main melting performed by the control device 30 in the main melting step will be described with reference to FIG. FIG. 13 is a diagram illustrating the fourth melting pattern.

[0084] 13 are points at which the powder material M is melted when forming the part 40. The points at which the electron beam L1 is irradiated are arranged in, for example, two rows and five columns.

[0085] 13, in the fourth main melting pattern, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to irradiate the heating beam onto the second unirradiated point from the right end of the top row (line) of the part 40, for example, to perform pre-melting pre-heating (Step 1). As a result, the area including the second heated point from the right end of the top row becomes the area that has been subjected to pre-melting pre-heating.

[0086] Next, the control device 30 controls the electron gun 2 to change the heating beam to a melting beam and melt the second heated point from the right end of the top row (Step 2). As a result, the second heated point from the right end of the top row becomes a melted point.

[0087] Next, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to move the focus to the third unirradiated point from the right end of the top row (the point immediately to the left of the melted point) and change the melting beam to a heating beam (step 3).At this time, the control device 30 moves the focus of the beam while changing from the melting beam to the heating beam.

[0088] Next, the control device 30 irradiates the third unirradiated point from the right end of the top row with the heating beam until a certain period of time has passed (step 4). As a result, the third unirradiated point from the right end of the top row becomes a heated point, and the area including the heated point becomes an area that has been subjected to pre-heating before melting.

[0089] Next, the control device 30 controls the electron gun 2 to change the heating beam to a melting beam and melt the third heated point from the right end of the top row (step 5). As a result, the third heated point from the right end of the top row becomes a melted point.

[0090] Next, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to move the focus to the fourth unirradiated point from the right end of the top row (the point immediately to the left of the melted point) and change the melting beam to a heating beam (step 6).At this time, the control device 30 moves the focus of the beam while changing from the melting beam to the heating beam.

[0091] In this way, the control device 30 controls the electron gun 2 and the beam deflection unit 10 to move the focal point to the next unirradiated point to be melted, and performs pre-heating before melting and main melting. Then, the control device 30 melts all unirradiated points on the part 40.

[0092] In this way, in the fourth main melting pattern, preheating (preheating before melting) and melting are performed for each unirradiated point (focal position) on the part 40. This makes it possible to reduce the temperature difference between the melted point and its surroundings. As a result, defects such as cracks are less likely to occur in the molded object when it solidifies after melting, and deterioration in the quality of the molded object can be suppressed or prevented.

[0093] [Beam setting for the fourth melting pattern] Next, the settings of the melting beam and the heating beam in the fourth main melting pattern will be described with reference to FIG. FIG. 14 is a table showing an example of settings of the melting beam and the heating beam in the fourth main melting pattern.

[0094] 14, the setting items of the melting beam and the heating beam include, for example, the beam current value, beam diameter, scan pitch, line spacing, scan speed, and acceleration voltage value. In the fourth melting pattern, the beam current value, beam diameter, scan speed, and acceleration voltage value of the heating beam and the melting beam are variables that can be set as appropriate.

[0095] The line spacing of the melting beams and heating beams of the fourth melting pattern is determined according to the spacing in the second direction Y between the multiple unirradiated points on the part 40. Therefore, the line spacing of the melting beams and heating beams of the fourth melting pattern will be the same value.

[0096] Furthermore, the scan pitch of the melting beam and heating beam of the fourth melting pattern is determined according to the spacing in the first direction X between the multiple unirradiated points on the part 40. Therefore, the scan pitch of the melting beam and heating beam of the fourth melting pattern will be the same value.

[0097] [Temperature distribution during melting] Next, the temperature distribution of the powder material M when pre-heating before melting is not performed and when pre-heating before melting is performed will be described with reference to FIGS. Fig. 15 is a diagram showing the temperature distribution during melting when preheating before melting is not performed in the fourth main melting pattern, and Fig. 16 is a diagram showing the temperature distribution during melting when main melting (with preheating before melting) is performed in the fourth main melting pattern.

[0098] The vertical axis of the graphs shown in Figures 15 and 16 represents the temperature of the powder material M. The vertical axis of the graphs shown in Figures 15 and 16 represents the distance in the first direction X (direction parallel to the rows) or the second direction (direction parallel to the columns).

[0099] The temperature distribution shown in Figure 15 is the temperature distribution when the entire surface of the powder material M is heated in the first preheating step, and then main melting is performed without performing preheating before melting as shown in the fourth main melting pattern. As shown in Figure 15, the temperature at the melting point is high, but the temperature at a point d (µm) away from the center of the melting point in the first direction X is significantly different from the temperature at the melting point (d > radius of the melting point). Therefore, defects such as cracks are likely to occur in the molded object when it solidifies after melting.

[0100] The temperature distribution shown in Figure 16 represents the temperature distribution during main melting after pre-melting preheating as shown in the fourth main melting pattern. As shown in Figure 16, a point d (μm) away from the center of the melting point in the first direction X is included in the area where pre-melting preheating was performed. Therefore, the temperature at the point d (μm) away from the center of the melting point in the first direction X is only slightly different from the temperature at the melting point. Therefore, defects such as cracks are less likely to occur in the molded object when it solidifies after melting.

[0101] The above describes embodiments of the present invention. However, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention as defined in the claims. For example, the above-described embodiments are intended to provide a detailed and easy-to-understand description of the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0102] In the second and third main melting patterns according to the above-described embodiment, preheating (preheating before melting) and melting were performed for each row extending in the first direction X. However, the main melting pattern according to the present invention may be, for example, one in which preheating (preheating before melting) and melting are performed for each column extending in the second direction Y. Furthermore, the main melting pattern according to the present invention may be one in which preheating (preheating before melting) and melting are performed for each line extending in any direction intersecting the first direction X and the second direction Y.

[0103] In the above-described embodiment, the electron gun 2 that emits the electron beam L1 is used as the beam emitter, but the present invention is not limited to this. For example, the beam emitter of the present invention may be an irradiation gun that emits a laser beam. In this case, the laser beam may be irradiated onto unirradiated points of the powder material M1 to melt and solidify it. [Explanation of symbols]

[0104] REFERENCE SIGNS LIST 1...3D additive manufacturing device, 2...electron gun (beam emission section), 3...deflection amplifier, 4...lens, 5...powder material storage, 6...stage, 7...powder deposition arm, 8...coordinate conversion correction circuit, 10...beam deflection section, 21...emitter, 22...extraction electrode, 23...acceleration electrode, 24...acceleration power supply, 30...control section, L1...electron beam, M1...powder material

Claims

1. a stage on which a powder layer made of powder material is spread; a beam emission unit that emits a beam toward the powder layer spread on the stage; a beam deflection unit that deflects the beam emitted from the beam emission unit; a control unit that controls the beam output unit and the beam deflection unit, The control unit controls the beam emission unit and the beam deflection unit to perform pre-melting preheating by heating the area corresponding to the part to be manufactured with the heating beam before melting the area corresponding to the part in the powder layer spread on the stage with the melting beam. 3D additive manufacturing equipment.

2. the control unit controls the beam emission unit and the beam deflection unit to perform a preheating step of heating the entire surface of the powder layer on the stage; After the preheating step, a melting step is performed by controlling the beam emitting unit and the beam deflecting unit to melt the region corresponding to the part; The pre-heating before melting is carried out in the melting step. The three-dimensional additive manufacturing apparatus according to claim 1 .

3. The diameter of the heating beam is smaller than the diameter of the melting beam. The three-dimensional additive manufacturing apparatus according to claim 1 .

4. The scanning speed of the heating beam is faster than the scanning speed of the melting beam. The three-dimensional additive manufacturing apparatus according to claim 1 .

5. The control unit controls the beam emission unit and the beam deflection unit to irradiate the heating beam onto the entire surface of the region corresponding to the part to perform the pre-melting preheating, and then irradiate the melting beam onto the entire surface of the region corresponding to the part to perform the melting. The three-dimensional additive manufacturing apparatus according to claim 1 .

6. The control unit controls the beam emission unit and the beam deflection unit to perform the pre-melting preheating by irradiating the heating beam for each arbitrary line in the area corresponding to the part and the melting by irradiating the melting beam for each arbitrary line in the area corresponding to the part. The three-dimensional additive manufacturing apparatus according to claim 1 .

7. The control unit controls the direction in which the pre-melting preheating and the melting are performed for each of the arbitrary lines to be unidirectional. The three-dimensional additive manufacturing apparatus according to claim 6.

8. The control unit controls the directions of the pre-melting preheating and the melting in the adjacent arbitrary lines to be opposite to each other. The three-dimensional additive manufacturing apparatus according to claim 6.

9. The control unit controls the beam emission unit and the beam deflection unit to perform the pre-melting preheating by irradiating the heating beam for each focal position corresponding to the part and the melting by irradiating the melting beam for each focal position corresponding to the part. The three-dimensional additive manufacturing apparatus according to claim 1 .

10. In a melting step, a region of the powder layer spread on the stage corresponding to a part to be manufactured is melted. The control unit controls the beam emission unit and the beam deflection unit to perform pre-melting preheating by heating the area corresponding to the part with the heating beam before melting the area corresponding to the part with the melting beam. Three-dimensional additive manufacturing method.

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