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

Abstract

To provide a three dimensional lamination shaping apparatus and a three dimensional lamination shaping method capable of improving the quality of a three dimensional structure to be shaped by forming a uniform molten surface.SOLUTION: An additive manufacturing device includes a stage, a beam emission part, a beam deflection part 10, and a control device 30. The beam deflecting section 10 deflects the beam emitted from the beam emitting section. The control device 30 controls the beam deflector 10. The control device 30 determines a next irradiation position, which is a position to be irradiated with the beam next, based on the rank assigned to each unirradiated position that has not yet been irradiated with the beam. Further, the control device 30 controls the beam deflector 10 to irradiate the next irradiation position with the beam. The rank is determined based on the molten state around each non-irradiation position, and is updated for each beam irradiation.SELECTED DRAWING: Figure 2

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 device. The three-dimensional additive manufacturing device described in Patent Document 1 divides a manufacturing area of ​​powder material into multiple lines, scans each line in turn with a beam, and melts the powder material line by line. Furthermore, between the end of beam scanning of the Mth line (M is a natural number) and the start of beam scanning of the M+1th line, a dummy scan is performed in which the beam scans without melting the powder material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2022-144439 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the 3D additive manufacturing device described in Patent Document 1 has differences in the amount of irregularities and defects on the melted surface at the start and end of the line. Therefore, there is a demand for a 3D additive manufacturing device that can form a uniform melted surface.

[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 form a uniform melting surface and improve 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 deflection unit. The control unit determines a next irradiation position, which is a position to be irradiated with the beam next, based on a rank assigned to each unirradiated position that has not yet been irradiated with the beam. The control unit also controls the beam deflection unit to irradiate the next irradiation position with the beam. The rank is determined based on the melting state around each unirradiated position, and is updated with each irradiation of the beam.

[0008] A three-dimensional additive manufacturing method embodying one aspect of the present invention includes a next irradiation position determination step and a beam irradiation step. In the next irradiation position determination step, a control unit determines a next irradiation position, which is a position to be irradiated with the beam next, based on a rank assigned to each unirradiated position that has not yet been irradiated with the beam and a recommended movement range that does not require settling time when deflecting the beam. In the beam irradiation step, the control unit controls the beam deflection unit to irradiate the beam at the next irradiation position. The rank is determined based on the melting state around each unirradiated position and is updated each time the beam is irradiated onto the powder layer. [Effects of the Invention]

[0009] According to the three-dimensional additive manufacturing device and three-dimensional additive manufacturing method configured as described above, a uniform melt surface can be formed, thereby improving the quality of the three-dimensional structure to be manufactured. [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. 2 is a diagram illustrating a first example of a recommended movement range according to an embodiment. [Figure 4] FIG. 10 is a diagram illustrating a second example of a recommended movement range according to an embodiment. [Figure 5] 10A and 10B are diagrams illustrating the transition of the recommended movement range when the end of beam irradiation is near according to one embodiment. [Figure 6] 10A and 10B are diagrams illustrating first and second examples of ranking according to an embodiment. [Figure 7] 10A and 10B are diagrams illustrating third and fourth examples of ranking according to an embodiment. [Figure 8] 10A and 10B are diagrams illustrating fifth and sixth examples of ranking according to an embodiment. [Figure 9] 10A and 10B are diagrams illustrating seventh and eighth examples of ranking according to an embodiment. [Figure 10] FIG. 4 is a diagram illustrating a first example of a correction table according to an embodiment. [Figure 11] FIG. 10 is a diagram illustrating a second example of a correction table according to an embodiment. [Figure 12] FIG. 10 is a diagram illustrating the relationship between priority and correction amount for rank according to an embodiment. [Figure 13] FIG. 10 is a diagram illustrating a beam irradiation order based on rank according to an embodiment. [Figure 14] FIG. 10 is a diagram illustrating a beam irradiation order based on rank according to an embodiment. [Figure 15] FIG. 10 is a diagram illustrating a beam irradiation order based on rank according to an embodiment. [Figure 16] 10A and 10B are diagrams illustrating the order of beam irradiation based on ranks and recommended movement ranges according to an embodiment. [Figure 17] 10A and 10B are diagrams illustrating the order of beam irradiation based on ranks and recommended movement ranges according to an embodiment. [Figure 18] 10A and 10B are diagrams illustrating the order of beam irradiation based on ranks and recommended movement ranges according to an embodiment. [Figure 19]10A and 10B are diagrams illustrating the order of beam irradiation based on ranks and recommended movement ranges according to an embodiment. [Figure 20] 10A and 10B are diagrams illustrating the order of beam irradiation based on ranks and recommended movement ranges according to an embodiment. [Figure 21] 10A and 10B are diagrams illustrating the order of beam irradiation based on ranks and recommended movement ranges according to an embodiment. [Figure 22] 10A and 10B are diagrams illustrating the order of beam irradiation based on ranks and recommended movement ranges according to an embodiment. [Figure 23] 10 is a flowchart illustrating an example of a beam irradiation process according to an embodiment. 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 23. Note that common members in the figures are given 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] When the beam deflection unit 10 deflects the electron beam L1 significantly, it is necessary to take a long time for the magnetic field to settle. This causes a discrepancy between the beam irradiation coordinates in the control command and the actual beam irradiation coordinates. To prevent this discrepancy, a waiting time (so-called settling time) is required after the electron beam L1 is deflected to eliminate the discrepancy. By providing a settling time, the fatal discrepancy between the control command and the actual beam irradiation coordinates is eliminated. However, if the settling time is long, the modeling time will be longer.

[0027] [Control Unit] Next, the functional configuration of the control device 30 will be described with reference to FIG.

[0028] The control device 30 includes a rank determining unit 31, an irradiation position determining unit 32, a beam correcting unit 33, and a storage unit .

[0029] The rank determination unit 31 determines the rank of each unirradiated position in each layer of the powder material M1 based on the melted state of the powder material M1. An unirradiated position is a position that has not yet been irradiated with the electron beam L1. The rank determination unit 31 identifies each unirradiated position by its coordinates. The positions (coordinates) to which the electron beam L1 is irradiated in each layer of the powder material M1 are stored in the memory unit 34. The ranking of each unirradiated position by the rank determination unit 31 will be described later.

[0030] The irradiation position determination unit 32 determines the next position to be irradiated with the electron beam L1 (hereinafter referred to as the "next irradiation position") based on the rank of each unirradiated position determined by the rank determination unit 31. A higher rank has a higher priority. Therefore, the irradiation position determination unit 32 determines the unirradiated position with the highest rank among the multiple ranks at that time as the next irradiation position.

[0031] The irradiation position determination unit 32 preferentially selects the next irradiation position from within a range where no settling time is required when deflecting the electron beam L1 (hereinafter referred to as the "recommended movement range"). If there are multiple positions within the recommended movement range that are the highest rank among multiple ranks at that time, the irradiation position determination unit 32 selects the next irradiation position based on predetermined parameters. Examples of parameters include prioritizing the position located in the upper left, the position located in the lower right, or random selection.

[0032] If the highest rank among the multiple ranks at that time is not present within the recommended movement range, the irradiation position determination unit 32 determines the highest ranked unirradiated position outside the recommended movement range as the next irradiation position.If there are multiple highest ranked positions outside the recommended movement range, the irradiation position determination unit 32 determines the position closest to the center of the recommended movement range as the next irradiation position.

[0033] Furthermore, when there are multiple positions that are closest to the center of the recommended movement range, the irradiation position determination unit 32 selects the next irradiation position based on predetermined parameters. The parameters may be the same as those used when there are multiple positions with the highest rank within the recommended movement range, or may be set separately for determining the next irradiation position outside the recommended movement range.

[0034] The beam correction unit 33 corrects the electron beam L1 according to the rank of the next irradiation position. The beam correction unit 33 can correct at least one of the intensity of the electron beam L1, the diameter of the electron beam L1, and the irradiation time of the electron beam L1. When the electron beam L1 is irradiated to an unirradiated position assigned a specific rank, the beam correction unit 33 does not correct the electron beam L1. A specific rank is assigned to an unirradiated position that does not have a melted area around it, for example.

[0035] The beam correction unit 33 corrects the intensity of the electron beam L1 by controlling the amount of beam current supplied to the electron gun 2. The beam correction unit 33 corrects the diameter of the electron beam L1 by controlling the position of the lens 4. The beam correction unit 33 generates the above-mentioned irradiation time command signal and transmits it to the beam deflection unit 10.

[0036] [Recommended movement range] Next, the recommended movement range used by the irradiation position determination unit 32 when determining the next irradiation position will be described with reference to FIGS.

[0037] (First example of recommended movement range) 3A and 3B are diagrams showing a recommended movement range S1, which is a first example of a recommended movement range. The points irradiated with the electron beam L1 shown in FIGS. 3A and 3B are aligned in a first direction X parallel to the horizontal direction and a second direction Y parallel to the horizontal direction and substantially perpendicular to the first direction X. In FIGS. 3A and 3B, the first direction X is the left-right direction, and the second direction Y is the up-down direction. Note that the points irradiated with the electron beam L1 are not limited to being aligned along two directions that intersect substantially perpendicularly, and may be aligned along two directions that intersect at any angle, for example.

[0038] 3A and 3B, the recommended movement range S1 is set to a square. The distance from the center of the recommended movement range S1 to each side is, for example, a predetermined distance R. The predetermined distance R is determined, for example, according to a distance at which no settling time is required when deflecting the electron beam L1 emitted by the electron gun 2. Note that, although it is preferable that the settling time for the recommended movement range according to the present invention is "0," this can be set arbitrarily.

[0039] The irradiation position determination unit 32 does not use the recommended movement range S1 when determining the irradiation position of the electron beam L1 for the first time. When determining the irradiation position of the electron beam L1 for the second time or later, the irradiation position determination unit 32 sets the most recent (current) beam irradiation position as the center of the recommended movement range S1.

[0040] As shown in Fig. 3A, the irradiation position determination unit 32 extracts the unirradiated point with the highest priority rank from among a plurality of unirradiated positions (hereinafter referred to as "unirradiated points") that are inside the recommended movement range S1. Alternatively, as shown in Fig. 3B, the irradiation position determination unit 32 may extract the unirradiated point with the highest priority rank from a plurality of unirradiated points that are included even slightly inside the recommended movement range S1.

[0041] The irradiation position determination unit 32 determines the next irradiation position from among the extracted multiple unirradiated points or one unirradiated point. If there is no unirradiated point with the highest priority rank among the multiple unirradiated points inside the recommended movement range S1, the irradiation position determination unit 32 determines one of the multiple unirradiated points outside the recommended movement range S1 as the next irradiation position.

[0042] (Second example of recommended movement range) 4A and 4B are diagrams showing a second example of the recommended movement range S2. The points irradiated with the electron beam L1 shown in FIGS. 4A and 4B are aligned in the first direction X and the second direction Y.

[0043] 4A and 4B, the recommended movement range S2 is set to a circular shape. The radius of the recommended movement range S2 is, for example, a predetermined distance R. The predetermined distance R is determined, for example, according to a distance at which no settling time is required when deflecting the electron beam L1 emitted by the electron gun 2.

[0044] The irradiation position determination unit 32 does not use the recommended movement range S2 when determining the irradiation position of the electron beam L1 for the first time. When determining the irradiation position of the electron beam L1 for the second time or later, the irradiation position determination unit 32 sets the most recent (current) beam irradiation position as the center of the recommended movement range S2.

[0045] As shown in Fig. 4A, the irradiation position determination unit 32 extracts the unirradiated point with the highest priority rank from among a plurality of unirradiated positions (hereinafter referred to as "unirradiated points") inside the recommended movement range S2. Alternatively, as shown in Fig. 4B, the irradiation position determination unit 32 may extract the unirradiated point with the highest priority rank from a plurality of unirradiated points that are included even slightly inside the recommended movement range S2.

[0046] The irradiation position determination unit 32 determines the next irradiation position from among the extracted multiple unirradiated points or one unirradiated point. If there is no unirradiated point with the highest priority rank among the multiple unirradiated points inside the recommended movement range S2, the irradiation position determination unit 32 determines one of the multiple unirradiated points outside the recommended movement range S2 as the next irradiation position.

[0047] (Next irradiation position when beam irradiation is nearing completion) Next, the transition of the recommended movement range when the end of beam irradiation is near will be described with reference to FIG. FIG. 5 is a diagram for explaining the transition of the recommended movement range when the end of beam irradiation is near.

[0048] The number of irradiations shown in Fig. 5 n-2 In this example, the electron beam L1 is irradiated to point A. At this point, there are five unirradiated points remaining. The remaining five unirradiated points are ranked with the same rank. The irradiation position determination unit 32 sets the center of the recommended movement range S2 to point A. The number of irradiations t n-2 In this example, all points within the recommended movement range S2 have already been irradiated. Therefore, the irradiation position determination unit 32 determines the next irradiation position to be an unirradiated point B that is outside the recommended movement range S2 and closest to the center (point A) of the recommended movement range S2.

[0049] Number of irradiations tn-1 Then, the electron beam L1 is irradiated to point B. At this point, there are four unirradiated points remaining. The remaining four unirradiated points are ranked with the same priority. The irradiation position determination unit 32 sets the center of the recommended movement range S2 to point B. The number of irradiations t n-1 In this example, all points within the recommended movement range S2 have already been irradiated. Therefore, the irradiation position determination unit 32 determines the next irradiation position to be an unirradiated point C that is outside the recommended movement range S2 and closest to the center (point B) of the recommended movement range S2.

[0050] Number of irradiations t n Then, the electron beam L1 is irradiated to point C. At this point, there are three unirradiated points remaining. The remaining three unirradiated points are ranked with the same priority. The irradiation position determination unit 32 sets the center of the recommended movement range S2 to point C. The number of irradiations t n In the example, the recommended movement range S2 includes an unirradiated point D. Therefore, the irradiation position determination unit 32 determines the unirradiated point D as the next irradiation position.

[0051] Ranking Next, the ranking performed by the rank determination unit 31 will be described with reference to Figs. 6 to 9. As described above, the rank determination unit 31 determines (ranks) the rank of each unirradiated point based on the melting state around each unirradiated point. The points to be irradiated with the electron beam L1 shown in Figs. 6 to 9 are aligned in the first direction X and the second direction Y.

[0052] (First example of ranking) 6A is a diagram illustrating a first example of ranking. In the first example of ranking, the total number of irradiated points (hereinafter referred to as "irradiated points") within a designated range D1 centered on an unirradiated point is used as the rank number. Note that the designated range according to the present invention can be set as appropriate.

[0053] The designated range D1 is set to a square. The length of the designated range D1 in the first direction X and the second direction Y corresponds to five points to be irradiated with the electron beam L1. Therefore, the number of points to be irradiated with the electron beam L1 in the designated range D1 is 25. In the example shown in FIG. 6A, there are six irradiated points in the designated range D1. Therefore, the rank determination unit 31 determines the rank of the unirradiated point in the center of the designated range D1 to be "Rank 6."

[0054] When the number of irradiated points in the designated range D1 is the smallest, 0, the rank determination unit 31 determines the rank of the unirradiated point in the center of the designated range D1 to be "Rank 0." On the other hand, when the number of irradiated points in the designated range D1 is the largest, 24, the rank of the unirradiated point in the center of the designated range D1 is determined to be "Rank 24." That is, in the first example of ranking, the ranks are divided into 25 types, from "Rank 0" to "Rank 24."

[0055] In the first example of ranking, the rank determined has a lower priority as the number of irradiated points in the specified range D1 increases. Therefore, "Rank 0" has the highest priority, and "Rank 24" has the lowest priority. The rank changes every time the electron beam L1 is irradiated to an unirradiated point in the layer of powder material M1. Therefore, the rank determination unit 31 updates the rank every time the electron beam L1 is irradiated to an unirradiated point.

[0056] (Second example of ranking) FIG. 6B is a diagram illustrating a second example of ranking. In the second example of ranking, the rank number is the total number of irradiated points within a designated range D2 centered on an unirradiated point. The designated range D2 is set to a square. The lengths of the designated range D2 in the first direction X and the second direction Y correspond to three points to be irradiated with the electron beam L1. Therefore, the number of points to be irradiated with the electron beam L1 in the designated range D2 is nine.

[0057] In the example shown in FIG. 6B, there are three irradiated points in the designated range D2. Therefore, the rank determination unit 31 determines the rank of the unirradiated point in the center of the designated range D2 to be "Rank 3." In the second ranking example, the ranks are divided into nine types, "Rank 0" to "Rank 8." The ranks determined in the second ranking example have a lower priority as the number of irradiated points in the designated range D2 increases. Therefore, "Rank 0" has the highest priority, and "Rank 8" has the lowest priority.

[0058] (Third example of ranking) FIG. 7A is a diagram illustrating a third example of ranking. In the third example of ranking, the rank number is the total number of irradiated points that are completely contained within a designated range D3 centered on an unirradiated point. The designated range D3 is set to be circular. The radius r of the designated range D3 corresponds to approximately 2.5 points to be irradiated with the electron beam L1. The number of points that are completely contained within the designated range D3 is 13.

[0059] In the example shown in FIG. 7A, there are three irradiated points in the designated range D3. Therefore, the rank determination unit 31 determines the rank of the unirradiated point in the center of the designated range D3 to be "Rank 3." In the third ranking example, the ranks are divided into 13 types, from "Rank 0" to "Rank 12." The ranks determined in the third ranking example have a lower priority as the number of irradiated points in the designated range D3 increases. Therefore, "Rank 0" has the highest priority, and "Rank 8" has the lowest priority.

[0060] (Fourth example of ranking) FIG. 7B is a diagram illustrating a fourth example of ranking. In the fourth example of ranking, the rank number is the total number of irradiated points that are completely contained within a designated range D4 centered on an unirradiated point. The designated range D4 is set to be circular. The radius r of the designated range D4 corresponds to approximately 1.5 points to be irradiated with the electron beam L1. The number of points that are completely contained within the designated range D4 is five.

[0061] In the example shown in FIG. 7B, there is one irradiated point in the designated range D4. Therefore, the rank determination unit 31 determines the rank of the unirradiated point in the center of the designated range D4 to be "Rank 1." In the fourth ranking example, the ranks are divided into five types, "Rank 0" to "Rank 4." The ranks determined in the fourth ranking example have a lower priority as the number of irradiated points in the designated range D4 increases. Therefore, "Rank 0" has the highest priority, and "Rank 4" has the lowest priority.

[0062] (5th example of ranking) 8A is a diagram illustrating a fifth example of ranking. In the fifth example of ranking, the rank number is the total number of irradiated points that are included, even if only a little, in a designated range D3 centered on an unirradiated point. The designated range D3 is the same as that shown in FIG. 7A. The number of points that are included, even if only a little, in the designated range D3 is 25.

[0063] In the example shown in FIG. 8A, there are six irradiated points that are at least partly included in the designated range D3. Therefore, the rank determination unit 31 determines the rank of the unirradiated point at the center of the designated range D3 to be "Rank 6." In the fifth ranking example, the ranks are divided into 25 types, from "Rank 0" to "Rank 24." The ranks determined in the fifth ranking example have a lower priority as the number of irradiated points within the designated range D3 increases. Therefore, "Rank 0" has the highest priority, and "Rank 24" has the lowest priority.

[0064] (Sixth example of ranking) 8B is a diagram illustrating a sixth example of ranking. In the sixth example of ranking, the rank number is the total number of irradiated points that are included, even if only a little, in a designated range D4 centered on an unirradiated point. The designated range D4 is the same as that shown in FIG. 7A. The number of points that are included, even if only a little, in the designated range D4 is nine.

[0065] In the example shown in FIG. 8B, there are three irradiated points that are at least partly included in the designated range D4. Therefore, the rank determination unit 31 determines the rank of the unirradiated point in the center of the designated range D4 to be "Rank 3." In the sixth ranking example, the ranks are divided into nine types, "Rank 0" to "Rank 8." The ranks determined in the sixth ranking example have a lower priority as the number of irradiated points within the designated range D4 increases. Therefore, "Rank 0" has the highest priority, and "Rank 8" has the lowest priority.

[0066] (Seventh example of ranking) 9A is a diagram illustrating a seventh example of ranking. In the seventh example of ranking, the rank number is determined by the ratio of the area of ​​irradiated points included in a designated range D3 centered on an unirradiated point. The designated range D3 is the same as that shown in FIG. 7A. The ratio of the area of ​​irradiated points included in the designated range D3 ranges from 0% to 100%.

[0067] In the example shown in FIG. 9A, the proportion of the area of ​​irradiated points included in the designated range D3 is 26%. Therefore, the rank determination unit 31 determines the rank of the unirradiated point at the center of the designated range D3 to be "Rank 26." In the seventh example of ranking, the ranks are divided into 100 types, from "Rank 0" to "Rank 100." The ranks determined in the seventh example of ranking have a lower priority as the area of ​​irradiated points within the designated range D3 increases. Therefore, "Rank 0" has the highest priority, and "Rank 100" has the lowest priority.

[0068] (8th example of ranking) 9B is a diagram illustrating an eighth example of ranking. In the eighth example of ranking, the number of ranks is determined based on the area ratio of irradiated points included in a designated range D4 centered on an unirradiated point. The designated range D4 is the same as that shown in FIG. 7A. The area ratio of irradiated points included in the designated range D4 is divided into 10 ranks, for example, in 10% increments.

[0069] An area percentage of 0% to 9% is "Rank 0", an area percentage of 10% to 19% is "Rank 1", an area percentage of 20% to 29% is "Rank 2", an area percentage of 30% to 39% is "Rank 3", an area percentage of 40% to 49% is "Rank 4", an area percentage of 50% to 59% is "Rank 5", an area percentage of 60% to 69% is "Rank 6", an area percentage of 70% to 79% is "Rank 7", an area percentage of 80% to 89% is "Rank 8", and an area percentage of 90% to 100% is "Rank 9".

[0070] In the example shown in FIG. 9B, the proportion of the area of ​​irradiated points included in the designated range D4 is 28%. Therefore, the rank determination unit 31 determines the rank of the unirradiated point at the center of the designated range D4 to be "Rank 2." In the eighth ranking example, the rank determined has a lower priority as the proportion of the area of ​​irradiated points within the designated range D4 increases. Therefore, "Rank 0" has the highest priority, and "Rank 9" has the lowest priority.

[0071] [Correction Table] Next, the correction table referred to by the beam correction unit 33 will be described with reference to Fig. 10 and Fig. 11. As described above, the beam correction unit 33 corrects the electron beam L1 according to the rank of the point to be irradiated with the electron beam L1 (next irradiation position). In doing so, the beam correction unit 33 determines various correction values ​​by referring to the correction table stored in the storage unit 34.

[0072] (First example of a correction table) 10 is a diagram illustrating a first example of the correction table, which defines a beam current correction coefficient, a beam diameter correction coefficient, and an irradiation time correction coefficient for each rank.

[0073] 10, when the next irradiation position is "Rank 0", the beam current correction coefficient, the beam diameter correction coefficient, and the irradiation time correction coefficient are all "1". Therefore, when irradiating the electron beam L1 to the point of "Rank 0", the beam correction unit 33 does not correct the electron beam L1.

[0074] The beam current correction coefficient, beam diameter correction coefficient, and irradiation time correction coefficient when the next irradiation position is "Rank 1" are specified as, for example, "1.15," "1.15," and "1.1." Therefore, when irradiating the point "Rank 1" with the electron beam L1, the beam correction unit 33 corrects the beam current value, beam diameter, and irradiation time according to the respective correction coefficients.

[0075] Even when the electron beam L1 is irradiated onto a point of "Rank 2" or higher, the beam correction unit 33 corrects the beam current value, beam diameter, and irradiation time according to the respective correction coefficients. The correction coefficients are set appropriately depending on the powder material and the type of beam. The correction coefficients are not limited to the beam current correction coefficient, beam diameter correction coefficient, and irradiation time correction coefficient, and may be set appropriately depending on other control items to be corrected.

[0076] (Second example of correction table) 11 is a diagram illustrating a second example of the correction table, which defines the beam current correction amount, beam diameter correction amount, and irradiation time correction amount for each rank.

[0077] 11, when the next irradiation position is "Rank 0", the beam current correction amount, the beam diameter correction amount, and the irradiation time correction amount are all "0%". Therefore, when irradiating the electron beam L1 to the point of "Rank 0", the beam correction unit 33 does not correct the electron beam L1.

[0078] The beam current correction amount, beam diameter correction amount, and irradiation time correction amount when the next irradiation position is "Rank 1" are specified as, for example, "+15%, +15%, and +10%." Therefore, when irradiating the point "Rank 1" with the electron beam L1, the beam correction unit 33 corrects the beam current value, beam diameter, and irradiation time according to each correction amount.

[0079] Even when the electron beam L1 is irradiated onto a point of "Rank 2" or higher, the beam correction unit 33 corrects the beam current value, beam diameter, and irradiation time according to the respective correction amounts. The correction amounts are set appropriately depending on the powder material and the type of beam. The correction amounts are not limited to the beam current correction amount, beam diameter correction amount, and irradiation time correction amount, and may be set appropriately depending on other control items to be corrected.

[0080] As the number of ranks increases, the number of irradiated points around the point to be irradiated with the electron beam L1 increases. This makes it difficult for the point to be irradiated with the electron beam L1 to heat up. Therefore, as shown in Figures 10 and 11, the beam correction unit 33 performs corrections to increase the beam current value, beam diameter, and irradiation time as the number of ranks increases.

[0081] The correction coefficient and correction amount according to the present invention do not necessarily have to be those that increase the beam current value, etc. In other words, the correction coefficient may be set to less than 1, or the correction amount may be set to a negative value.

[0082] [Priority and correction amount] Next, the relationship between the priority order and the correction amount for the rank will be described with reference to FIG. FIG. 12 is a diagram showing the relationship between the priority order and the correction amount for each rank.

[0083] In the ranking example shown in Fig. 12, the rank number is the total number of irradiated points among the four points adjacent to the unirradiated point to be ranked in the first direction X and the second direction Y. In the ranking example shown in Fig. 12, the ranks are divided into five types, "Rank 0" to "Rank 4".

[0084] As shown in Figure 12, the priority decreases as the rank number increases. The irradiation position determination unit 32 determines the next irradiation position from among those with the highest priority. For example, if none of the unirradiated points in the layer of powder material M1 are assigned "Rank 0," the irradiation position determination unit 32 determines whether any of the unirradiated points in the layer of powder material M1 are assigned "Rank 1." If there are unirradiated points assigned "Rank 1," the irradiation position determination unit 32 selects the next irradiation position from among them.

[0085] As shown in FIG. 12, the correction amount (correction coefficient) increases as the rank number increases. The beam correction unit 33 refers to the correction table, determines the correction amount (correction coefficient) according to the rank of the next irradiation position, and corrects the beam current value, etc. An unirradiated point with a large rank number is selected as the next irradiation position in the latter half of the beam irradiation on the layer of powder material M1. Therefore, the correction amount of the beam current value, etc. increases in the latter half of the beam irradiation on the layer of powder material M1.

[0086] [Rank-based beam firing order] Next, the irradiation order of the electron beam L1 based on the rank will be described with reference to FIGS. 13 to 15 are diagrams for explaining the order of irradiation of beams based on rank.

[0087] 13 to 15, the points irradiated with the electron beam L1 are aligned in the first direction X and the second direction Y. A border is formed on the periphery of the region irradiated with the electron beam L1 (the part to be formed). The border is a wall formed when the powder material M1 is irradiated with the electron beam L1 and the powder material M1 is melted and solidified.

[0088] 13, t=0 is the timing before the first irradiation of the electron beam L1. There are a total of nine unirradiated points at t=0. The unirradiated points are points that are scheduled to be irradiated with the electron beam L1 but have not yet been irradiated with the electron beam L1.

[0089] Hereinafter, the first direction X is the left-right direction, and the second direction Y is the up-down direction, and the multiple unirradiated points are expressed as up-down, left-right, and right-left points based on the center. That is, the multiple unirradiated points at t=0 are the center unirradiated point, the upper unirradiated point, the lower unirradiated point, the left unirradiated point, the right unirradiated point, the upper left unirradiated point, the lower left unirradiated point, the upper right unirradiated point, and the lower right unirradiated point.

[0090] At t=0, the rank determination unit 31 determines the rank of each unirradiated point. The rank determination unit 31 determines the total number of irradiated points among the four points adjacent to the unirradiated point to be ranked in the vertical, horizontal, and vertical directions as the rank number. Therefore, the ranks are divided into five types: "Rank 0" to "Rank 4".

[0091] The numbers shown in Figures 13 to 15 indicate the rank of the unirradiated point at that time. For example, the central unirradiated point has all of its adjacent points above, below, left, and right that are unirradiated points. Therefore, the rank of the central unirradiated point is "Rank 0." The unirradiated point, bottom unirradiated point, left unirradiated point, and right unirradiated point have one adjacent point above, below, left, and right that is an irradiated point. Therefore, the rank of the top unirradiated point, bottom unirradiated point, left unirradiated point, and right unirradiated point is "Rank 1."

[0092] The upper left unirradiated point, the lower left unirradiated point, the upper right unirradiated point, and the lower right unirradiated point have one adjacent point that has been irradiated in the vertical and horizontal directions. Therefore, the rank of the upper left unirradiated point, the lower left unirradiated point, the upper right unirradiated point, and the lower right unirradiated point is "Rank 2". At t=0, the irradiation position determination unit 32 determines the central unirradiated point, which is "Rank 0", as the next irradiation position.

[0093] At t=1, the beam deflection unit 10 irradiates the central unirradiated point with the electron beam L1. As a result, the central unirradiated point becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. As a result, the ranks of the top unirradiated point, bottom unirradiated point, left unirradiated point, and right unirradiated point change from "Rank1" to "Rank2."

[0094] At t=1, the irradiation position determination unit 32 determines the right unirradiated point of "Rank 2" as the next irradiation position. At t=1, all of the remaining unirradiated points are of "Rank 2". Therefore, the irradiation position determination unit 32 determines the next irradiation position from among the multiple "Rank 2" irradiation points based on a predetermined parameter (in this example, random is used).

[0095] At t=2, the beam deflection unit 10 irradiates the right unirradiated point with the electron beam L1. As a result, the right unirradiated point becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. As a result, the ranks of the upper right unirradiated point and the lower right unirradiated point change from "Rank 2" to "Rank 3." At t=2, the irradiation position determination unit 32 determines the lower unirradiated point, which is "Rank 2," as the next irradiation position.

[0096] At t=3, the beam deflection unit 10 irradiates the bottom unirradiated point with the electron beam L1. As a result, the bottom unirradiated point becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. As a result, the rank of the bottom right unirradiated point changes from "Rank 3" to "Rank 4." At t=3, the irradiation position determination unit 32 determines the top left unirradiated point, which is "Rank 2," as the next irradiation position.

[0097] At t=4 shown in FIG. 14, the beam deflection unit 10 irradiates the upper left unirradiated point with the electron beam L1. As a result, the upper left unirradiated point becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. As a result, the ranks of the left unirradiated point and the upper irradiated point change from "Rank 2" to "Rank 3." At t=4, the irradiation position determination unit 32 determines the upper unirradiated point, which is "Rank 3," as the next irradiation position.

[0098] At t=5, the beam deflection unit 10 irradiates the upper unirradiated point with the electron beam L1. As a result, the upper unirradiated point becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. As a result, the rank of the upper right unirradiated point changes from "Rank 3" to "Rank 4." At t=5, the irradiation position determination unit 32 determines the lower left unirradiated point, which is "Rank 3," as the next irradiation position.

[0099] At t=6, the beam deflection unit 10 irradiates the lower left unirradiated point with the electron beam L1. As a result, the lower left unirradiated point becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. As a result, the rank of the left unirradiated point changes from "Rank 3" to "Rank 4". At t=6, the irradiation position determination unit 32 determines the left unirradiated point, which is "Rank 4", as the next irradiation position.

[0100] At t=7, the beam deflection unit 10 irradiates the left unirradiated point with the electron beam L1. As a result, the left unirradiated point becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. However, the ranks of the upper right unirradiated point and the lower right irradiated point remain unchanged from "Rank 4," which has the lowest priority. At t=7, the irradiation position determination unit 32 determines the lower right irradiated point, which has "Rank 4," as the next irradiation position.

[0101] At t=8, the beam deflection unit 10 irradiates the lower right unirradiated point with the electron beam L1. As a result, the lower right unirradiated point becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. However, the rank of the upper right unirradiated point remains unchanged from "Rank 4," which has the lowest priority. At t=8, the irradiation position determination unit 32 determines the upper right unirradiated point, which is the last unirradiated point, as the next irradiation position.

[0102] At t=9, the beam deflection unit 10 irradiates the upper right irradiation point with the electron beam L1. As a result, the lower right unirradiated point becomes an irradiated point. As a result, all unirradiated points are irradiated with the electron beam L1, and the beam irradiation process for one layer of the powder material M1 is completed.

[0103] [Beam irradiation order based on rank and recommended movement range] Next, the irradiation order of the electron beam L1 based on the rank and the recommended movement range will be described with reference to FIGS. 16 to 22 are diagrams for explaining the order of beam irradiation based on the rank and the recommended movement range.

[0104] 16 to 22, the points irradiated with the electron beam L1 are aligned in the first direction X and the second direction Y. A border is formed on the periphery of the region irradiated with the electron beam L1 (the part to be formed).

[0105] 16, t=0 is the timing before the first irradiation of the electron beam L1. At t=0, there are, for example, 25 unirradiated points in total. At t=0, the rank determination unit 31 determines the rank of each unirradiated point. The rank determination unit 31 determines the total number of irradiated points among the four points adjacent to the unirradiated point to be ranked in the vertical, horizontal, and vertical directions as the rank number. Therefore, the ranks are divided into five types, "Rank 0" to "Rank 4".

[0106] The numbers shown in FIGS. 16 to 22 indicate the rank of the unirradiated point at that time. The recommended movement range is set to a square. The lengths of the recommended movement range in the first direction X and the second direction Y correspond to three points to be irradiated with the electron beam L1. At t=0, the irradiation position determination unit 32 determines one of the multiple unirradiated points with "Rank 0" as the next irradiation position.

[0107] At t=1, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point determined as the next irradiation position. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=1, the irradiation position determination unit 32 determines the unirradiated point that is included in the recommended movement range and has "Rank 0" as the next irradiation position.

[0108] At t=2, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=1. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=2, the irradiation position determination unit 32 selects one of the multiple unirradiated points that are included in the recommended movement range and have a "Rank 0" based on predetermined parameters, and sets it as the next irradiation position.

[0109] At t=3, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated points determined as the next irradiation positions at t=2. The unirradiated points irradiated with the electron beam L1 become irradiated points. Then, the rank determination unit 31 updates the rank of each unirradiated point.

[0110] At t=3, there are no unirradiated points of "Rank 0" within the recommended movement range. On the other hand, there are multiple unirradiated points of "Rank 0" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the one of the multiple unirradiated points of "Rank 0" outside the recommended movement range that is closest to the center of the recommended movement range as the next irradiation position.

[0111] At t=4 shown in FIG. 17, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=3. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=4, there is no unirradiated point of "Rank 0" within the recommended movement range. On the other hand, there is an unirradiated point of "Rank 0" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the unirradiated point of "Rank 0" that is outside the recommended movement range as the next irradiation position.

[0112] At t=5, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated points determined as the next irradiation positions at t=4. The unirradiated points irradiated with the electron beam L1 become irradiated points. Then, the rank determination unit 31 updates the rank of each unirradiated point.

[0113] At t=5, there is no unirradiated point of "Rank 0" among the remaining unirradiated points. Therefore, the irradiation position determination unit 32 sets the unirradiated point of "Rank 1", which has the next highest priority, as a candidate for the next irradiation position. Then, the irradiation position determination unit 32 selects one of the unirradiated points of "Rank 1" that is included in the recommended movement range based on predetermined parameters, and sets it as the next irradiation position.

[0114] At t=6, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated points determined as the next irradiation positions at t=5. The unirradiated points irradiated with the electron beam L1 become irradiated points. Then, the rank determination unit 31 updates the rank of each unirradiated point.

[0115] At t=6, there are no unirradiated points of "Rank 1" within the recommended movement range. On the other hand, there are unirradiated points of "Rank 1" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the one closest to the center of the recommended movement range among the multiple unirradiated points of "Rank 1" outside the recommended movement range as the next irradiation position. Note that there are multiple unirradiated points of "Rank 1" closest to the center of the recommended movement range. In this case, the irradiation position determination unit 32 selects one unirradiated point based on predetermined parameters (for example, priority is given to the top left) and sets it as the next irradiation position.

[0116] At t=7, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated points determined as the next irradiation positions at t=6. The unirradiated points irradiated with the electron beam L1 become irradiated points. Then, the rank determination unit 31 updates the rank of each unirradiated point.

[0117] At t=7, there are no unirradiated points of "Rank 1" within the recommended movement range. On the other hand, there are unirradiated points of "Rank 1" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the one closest to the center of the recommended movement range among the multiple unirradiated points of "Rank 1" outside the recommended movement range as the next irradiation position.

[0118] At t=8 shown in FIG. 18, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=7. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=8, there is no unirradiated point of "Rank 1" within the recommended movement range. On the other hand, there is an unirradiated point of "Rank 1" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the unirradiated point of "Rank 1" that is outside the recommended movement range as the next irradiation position.

[0119] At t=9, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=8. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=9, there are no unirradiated points of "Rank 0" or "Rank 1" among the remaining unirradiated points. Therefore, the irradiation position determination unit 32 sets the unirradiated point of "Rank 2," which has the next highest priority, as a candidate for the next irradiation position.

[0120] At t=9, there are no unirradiated points of "Rank 2" within the recommended movement range. On the other hand, there are unirradiated points of "Rank 2" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the one closest to the center of the recommended movement range among the multiple unirradiated points of "Rank 2" outside the recommended movement range as the next irradiation position.

[0121] At t=10, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point determined as the next irradiation position at t=9. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point.

[0122] At t=10, there are no unirradiated points of "Rank 2" within the recommended movement range. On the other hand, there are unirradiated points of "Rank 2" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the one closest to the center of the recommended movement range among the multiple unirradiated points of "Rank 2" outside the recommended movement range as the next irradiation position.

[0123] At t=11, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated points that were determined as the next irradiation positions at t=10. The unirradiated points irradiated with the electron beam L1 become irradiated points. Then, the rank determination unit 31 updates the rank of each unirradiated point.

[0124] At t=11, there are no unirradiated points of "Rank 2" within the recommended movement range. On the other hand, there are unirradiated points of "Rank 2" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the one closest to the center of the recommended movement range among the multiple unirradiated points of "Rank 2" outside the recommended movement range as the next irradiation position.

[0125] At t=12 shown in FIG. 19, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=11. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=12, there is no unirradiated point of "Rank 2" within the recommended movement range. On the other hand, there is an unirradiated point of "Rank 2" outside the recommended movement range. Therefore, the irradiation position determination unit 32 determines the unirradiated point of "Rank 2" that is outside the recommended movement range as the next irradiation position.

[0126] At t=13, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated points determined as the next irradiation positions at t=12. The unirradiated points irradiated with the electron beam L1 become irradiated points. Then, the rank determination unit 31 updates the rank of each unirradiated point.

[0127] At t=13, there are no unirradiated points of "Rank 0" to "Rank 3" among the remaining unirradiated points. Therefore, the irradiation position determination unit 32 sets the unirradiated point of "Rank 4", which has the next highest priority, as a candidate for the next irradiation position. Then, the irradiation position determination unit 32 selects one of the unirradiated points of "Rank 4" that is included in the recommended movement range based on predetermined parameters, and sets it as the next irradiation position.

[0128] At t=14, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=13. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. The irradiation position determination unit 32 selects one of the multiple unirradiated points that are included in the recommended movement range and have a "Rank 4" based on predetermined parameters, and sets it as the next irradiation position.

[0129] At t=15, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=14. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=15, the irradiation position determination unit 32 determines the unirradiated point that is included in the recommended movement range and has "Rank 4" as the next irradiation position.

[0130] At t=16 shown in FIG. 20, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=15. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=16, the irradiation position determination unit 32 selects one of the multiple unirradiated points that are included in the recommended movement range and have a "Rank 4" based on predetermined parameters, and sets it as the next irradiation position.

[0131] At t=17, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=16. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=17, the irradiation position determination unit 32 determines the unirradiated point that is included in the recommended movement range and has "Rank 4" as the next irradiation position.

[0132] At t=18, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=17. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=18, the irradiation position determination unit 32 determines the unirradiated point that is included in the recommended movement range and has "Rank 4" as the next irradiation position.

[0133] At t=19, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=18. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=19, the irradiation position determination unit 32 selects one of the multiple unirradiated points that is included in the recommended movement range and has "Rank 4" based on predetermined parameters, and sets it as the next irradiation position.

[0134] At t=20 shown in FIG. 21, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=19. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=20, the irradiation position determination unit 32 determines the unirradiated point that is included in the recommended movement range and has "Rank 4" as the next irradiation position.

[0135] At t=21, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=20. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=21, the irradiation position determination unit 32 determines the unirradiated point that is included in the recommended movement range and has "Rank 4" as the next irradiation position.

[0136] At t=22, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=21. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=22, the irradiation position determination unit 32 selects one of the multiple unirradiated points that is included in the recommended movement range and has "Rank 4" based on predetermined parameters, and sets it as the next irradiation position.

[0137] At t=23, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=22. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=23, the irradiation position determination unit 32 determines the unirradiated point that is included in the recommended movement range and has "Rank 4" as the next irradiation position.

[0138] At t=24, the beam deflection unit 10 irradiates the electron beam L1 to the unirradiated point that was determined as the next irradiation position at t=23. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. Then, the rank determination unit 31 updates the rank of each unirradiated point. At t=24, the irradiation position determination unit 32 determines the unirradiated point that is included in the recommended movement range and has "Rank 4" as the next irradiation position.

[0139] At t=25, the beam deflection unit 10 irradiates the electron beam L1 to the last unirradiated point that was determined as the next irradiation position at t=24. The unirradiated point irradiated with the electron beam L1 becomes an irradiated point. As a result, all unirradiated points are irradiated with the electron beam L1, and the beam irradiation process for one layer of the powder material M1 is completed.

[0140] As described above, in this embodiment, the rank determination unit 31 determines the rank of each unirradiated point (position) based on the melting state of the surrounding area. Then, the irradiation position determination unit 32 refers to the rank of each unirradiated point and prioritizes unirradiated points with less melting state around them as the next irradiation position. This allows the electron beam L1 to be discretely irradiated onto one layer of the powder material M1, forming a uniform melted surface. As a result, the quality of the molded object (three-dimensional structure) can be improved.

[0141] Furthermore, the irradiation position determination unit 32 prioritizes unirradiated points with little surrounding molten state that are within the recommended movement range as the next irradiation position. This prevents the electron beam L1 from being significantly changed. As a result, the settling time can be shortened, and the time required for lamination and modeling can be shortened.

[0142] [Beam irradiation processing] Next, the beam irradiation process performed by the beam deflection unit 10 and the control device 30 of the three-dimensional additive manufacturing apparatus 1 will be described with reference to FIG. FIG. 23 is a flowchart showing an example of the beam irradiation process.

[0143] First, the irradiation position determination unit 32 of the control device 30 resets or corrects the irradiation preparatory group (S1). The irradiation preparatory group is a group of unirradiated points that are candidates for the next irradiation position.

[0144] When irradiating one layer of powder material M1 with the electron beam L1 for the first time, the irradiation preliminary group used in the layer immediately below may remain in the memory unit 34 (for example, RAM in the memory unit 34). Also, when irradiating one layer of powder material M1 with the electron beam L1 for the second or subsequent times, the irradiation preliminary group used in the previous irradiation with the electron beam L1 may remain in the memory unit 34. Therefore, the irradiation position determination unit 32 resets (deletes) the irradiation preliminary group remaining in the memory unit 34.

[0145] Next, the rank determination unit 31 determines the ranks of all unirradiated points in one layer (within the surface) of the powder material M1 (S2). Subsequently, the irradiation position determination unit 32 sets all unirradiated points with the highest priority rank among the ranked unirradiated points (the last one) as a preliminary irradiation group (S3).

[0146] Next, the irradiation position determination unit 32 determines whether any of the irradiation preliminary group is included in the recommended movement range (S4). In step S4, when it is determined that any of the irradiation preliminary group is included in the recommended movement range (YES determination in S4), the irradiation position determination unit 32 extracts each unirradiated point of the irradiation preliminary group that is included in the recommended movement range (S5).

[0147] In step S4, when it is determined that none of the irradiation preliminary group is included in the recommended movement range (if S4 is determined as NO), the irradiation position determination unit 32 extracts all unirradiated points in the irradiation preliminary group that are closest to the center of the recommended movement range (S6).

[0148] After the processing of step S5 or step S6, the irradiation position determination unit 32 determines whether or not multiple unirradiated points have been extracted (S7). When it is determined in step S7 that multiple unirradiated points have been extracted (YES determination in S7), the irradiation position determination unit 32 extracts one unirradiated point from the multiple unirradiated points based on predetermined parameters (S8).

[0149] In step S7, when it is determined that multiple unirradiated points have not been extracted (if S7 is determined to be NO), or after processing of step S8, the irradiation position determination unit 32 determines one extracted unirradiated point as the next irradiation position (S9).

[0150] Next, the irradiation position determination unit 32 sends a position control signal to the beam deflection unit 10 to move the focus of the electron beam L1 to the next irradiation position (S10). Next, the beam correction unit 33 determines the correction of the electron beam L1 according to the rank of the unirradiated point, which is the next irradiation position, and applies the correction to the beam deflection unit 10 and the electron gun 2 (S11).

[0151] Next, the control device 30 controls the driving of the electron gun 2 to emit the electron beam L1 from the electron gun 2 (S12). As a result, the electron beam L1, which has been appropriately corrected, is irradiated onto the next irradiation position. Next, the control device 30 determines whether or not this is the last beam irradiation for one layer of the powder material M1 (S13).

[0152] In step S13, when it is determined that this is not the last beam irradiation in one layer of the powder material M1 (if S13 is determined as NO), the control device 30 returns the process to step S1. Then, the control device 30 performs the processes from step S1 to step S9 while the electron beam L1 is being irradiated to the next irradiation position.

[0153] In step S13, when it is determined that this is the final beam irradiation for one layer of powder material M1 (YES in S13), the control device 30 ends the beam irradiation process for one layer of powder material M1. After that, when the next layer of powder material M1 is formed, the control device 30 starts the beam irradiation process for the next layer of powder material M1.

[0154] [Irradiation order data] The rank of each unirradiated point, which is updated each time the electron beam L1 is irradiated, and the next irradiation position, which is determined based on the rank, can be determined in advance before the start of the beam irradiation process. Therefore, the rank determination unit 31 and the irradiation position determination unit 32 may determine in advance irradiation order data that specifies the irradiation positions from the first irradiation to the final irradiation in each layer of the powder material M1 and the rank of each irradiation position.

[0155] The rank determination unit 31 obtains all irradiation positions (irradiation coordinates) from the shaping data for forming the shaped object. The shaping 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 shaping 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.

[0156] The irradiation order data is generated by repeating steps S1 to S9 in the above-described beam irradiation process (see FIG. 22). First, the rank determination unit 31 determines the rank of each unirradiated point in one layer of the powder material M1. Next, the irradiation position determination unit 32 determines the initial beam irradiation position (next irradiation position) based on the rank determined by the rank determination unit 31. This determines the initial beam irradiation position and its rank in one layer of the powder material M1.

[0157] Next, the rank determination unit 31 changes the initial beam irradiation position to an irradiated point and determines the rank of each unirradiated point. Next, the irradiation position determination unit 32 determines the second beam irradiation position (next irradiation position) based on the rank determined by the rank determination unit 31. In this way, the second beam irradiation position and its rank in one layer of the powder material M1 are determined.

[0158] The rank determination unit 31 and the irradiation position determination unit 32 repeat the determination of the rank and irradiation position until the final beam irradiation position and its rank in one layer of the powder material M1 are determined. In this way, the rank determination unit 31 and the irradiation position determination unit 32 determine all beam irradiation positions and their ranks in each layer of the powder material M1. As a result, irradiation order data is generated. The rank determination unit 31 and the irradiation position determination unit 32 store the generated irradiation order data in a memory unit.

[0159] If the irradiation order data is available, steps S9 to S13 in the above-described beam irradiation process (see FIG. 22) are performed. In step S9, the irradiation position determination unit 32 determines the beam irradiation position (next irradiation position) by referring to the irradiation order data. In step S11, the rank of the beam irradiation position (next irradiation position) is acquired by referring to the irradiation order data, and the correction of the electron beam L1 according to the rank is determined by referring to the correction table.

[0160] The irradiation order data may include a correction coefficient (correction amount) for each beam irradiation position. In this case, the beam corrector 33 determines the correction coefficient (correction amount) for each beam irradiation position by referring to the irradiation order data.

[0161] Furthermore, the irradiation order data is not limited to being generated by the control device 30. For example, a modeling data creation device that creates modeling data may generate the irradiation order data. The irradiation order data is supplied to the control device 30 via a communication line and stored in the memory unit 34 of the control device 30. Furthermore, the irradiation order 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.

[0162] 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.

[0163] In the above-described embodiment, the positions where the electron beam L1 is irradiated are aligned along the first direction X and the second direction Y, which intersect at approximately right angles. However, according to the present invention, the positions where the electron beam L1 is irradiated may be aligned along two directions that intersect at any angle.

[0164] 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]

[0165] 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, 31...rank determination section, 32...irradiation position determination section, 33...beam correction section, 34...memory section, D1, D2, D3, D4...designated range, L1...electron beam, M1...powder material, S1, S2...recommended movement range

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 deflection unit, the control unit determines a next irradiation position, which is a position to be next irradiated with the beam, based on the rank assigned to each unirradiated position that has not yet been irradiated with the beam, and controls the beam deflection unit to irradiate the next irradiation position with the beam; The rank is determined based on the melting state around each unirradiated position and is updated each time the beam is irradiated. 3D additive manufacturing equipment.

2. The control unit determines the next irradiation position based on a recommended movement range in which no settling time is required when deflecting the beam. The three-dimensional additive manufacturing apparatus according to claim 1 .

3. The recommended movement range is the inside of a square or circle centered on the nearest beam irradiation position. The three-dimensional additive manufacturing apparatus according to claim 2 .

4. When there are a plurality of unirradiated positions that have been assigned the highest rank among the plurality of ranks at that time within the recommended movement range, the control unit sets one of the unirradiated positions as the next irradiation position based on predetermined parameters. The three-dimensional additive manufacturing apparatus according to claim 2 .

5. When the unirradiated position assigned the highest rank, which has the highest priority among the plurality of ranks at that time, is not within the recommended movement range, the control unit sets the unirradiated position assigned the highest rank that is outside the recommended movement range and closest to the center of the recommended movement range as the next irradiation position. The three-dimensional additive manufacturing apparatus according to claim 2 .

6. When there are a plurality of unirradiated positions that are assigned the highest rank and are closest to the center of the recommended movement range outside the recommended movement range, the control unit sets one unirradiated position as the next irradiation position based on predetermined parameters. The three-dimensional additive manufacturing apparatus according to claim 5 .

7. The rank indicates that the higher the ratio of the area irradiated with the beam within the specified range centered on each unirradiated position, the lower the priority. The three-dimensional additive manufacturing apparatus according to claim 1 .

8. The rank is such that the more points irradiated with the beam within a specified range centered on each unirradiated position, the lower the priority. The three-dimensional additive manufacturing apparatus according to claim 1 .

9. The control unit has a beam correction unit that corrects the beam in accordance with the rank of the next irradiation position when irradiating the beam to the next irradiation position. The three-dimensional additive manufacturing apparatus according to claim 1 .

10. The beam correction unit corrects at least one of the intensity of the beam, the diameter of the beam, and the irradiation time of the beam. The three-dimensional additive manufacturing apparatus according to claim 9.

11. The control unit has a rank determination unit that determines the rank. The three-dimensional additive manufacturing apparatus according to claim 1 .

12. The control unit has a storage unit that stores irradiation order data including a plurality of next irradiation positions determined based on the rank of each unirradiated position and the rank of each of the plurality of next irradiation positions. The three-dimensional additive manufacturing apparatus according to claim 1 .

13. the irradiation order data includes correction data for correcting the beams to be irradiated at the plurality of next irradiation positions; The correction data is defined according to the ranks of the plurality of next irradiation positions. The three-dimensional additive manufacturing apparatus according to claim 12.

14. The correction data is data for correcting at least one of the intensity of the beam, the diameter of the beam, and the irradiation time of the beam. The three-dimensional additive manufacturing apparatus according to claim 13.

15. a rank determining unit determining a rank for each unirradiated position based on a melting state around each unirradiated position that has not yet been irradiated with the beam; an irradiation position determination unit determines a next irradiation position, which is a position to be irradiated with the beam next, based on the rank, and controls a beam deflection unit to irradiate the beam at the next irradiation position; The rank determining unit determines a rank for each unirradiated position for each irradiation of the beam. Three-dimensional additive manufacturing method.

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