Additional processing method, additional processing apparatus, and additional processing program

Abstract

Provided is a technique for improving the shaping accuracy of a pilot hole for tapping more than before. 【Solution means】The additional processing method includes a step of lowering the floor surface of the processing area, a step of spreading a metal powder material over the processing area after lowering the floor surface of the processing area, a step of irradiating the metal powder material spread over the processing area with a laser beam, and repeating the steps of lowering, spreading, and irradiating to perform a step of laminating a workpiece having a predetermined shape in the processing area. The workpiece includes a first pilot hole for which tapping is planned. The first pilot hole is laminated such that its depth direction is inclined with respect to the lamination direction, and when the angle of inclination of the tangent line on the line of the upper half of the first pilot hole in a cross-sectional view in the direction orthogonal to the depth direction with respect to the lamination direction is defined as angle θ, the lamination is performed such that the line where angle θ is less than a predetermined angle is longer than the line where angle θ is greater than or equal to the predetermined angle.

Description

Technical Field

[0001] The present disclosure relates to an additive processing method, an additive processing apparatus, and an additive processing program.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2022-33955 (Patent Document 1) discloses a layered manufacturing apparatus that performs layered processing by the SLM (Selective Laser Melting) method. The SLM method is a method of realizing layered processing by irradiating a laser beam onto a metal powder material spread over a processing area and locally melting and solidifying the metal powder material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] After the layered processing, some removal processing may be performed. Patent Document 1 does not disclose the removal processing in the post-process of the layered processing. An example of the removal processing is tapping for forming a threaded hole.

[0005] In order to efficiently perform the tapping in the post-process, a pilot hole may be pre-formed during the layered processing of the workpiece. When forming the pilot hole, the laser beam is not irradiated inside the pilot hole. Therefore, the inner surface of the pilot hole comes into contact with the metal powder material. Therefore, the inner surface of the pilot hole is more likely to collapse than other parts.

[0006] The present disclosure has been made to solve the above-described problems, and an object in one aspect is to provide a technique for improving the forming accuracy of a pilot hole for tapping more than before.

Means for Solving the Problem

[0007] In an example of the present disclosure, a method for additional processing of a workpiece is provided. The additional processing method includes steps of lowering the floor surface of the processing area of the workpiece, spreading a metal powder material over the processing area after lowering the floor surface of the processing area, irradiating the metal powder material spread over the processing area with a laser beam, repeating the lowering step, the spreading step, and the irradiating step, and laminating a workpiece having a predetermined shape in the processing area. The workpiece having the predetermined shape includes a first counterbore scheduled to be tapped. The first counterbore is laminated such that the depth direction of the first counterbore is inclined with respect to the lamination direction of the workpiece. When the angle between the tangent line on the line of the upper half of the first counterbore in a cross-sectional view of the first counterbore in the direction orthogonal to the depth direction and the lamination direction is defined as an angle θ, the laminated line where the angle θ is less than a predetermined angle is longer than the line where the angle θ is greater than or equal to the predetermined angle.

[0008] The predetermined angle is 45 degrees.

[0009] In an example of the present disclosure, the shape of the first counterbore in the cross-sectional view is an elliptical shape or a teardrop shape.

[0010] In an example of the present disclosure, the workpiece laminated in the laminating step includes a second counterbore scheduled to be tapped. The second counterbore is laminated such that the depth direction of the second counterbore is parallel to the lamination direction. The lamination is performed such that the cross-section in the direction orthogonal to the lamination direction is circular.

[0011] In an example of the present disclosure, in the step of performing the laminated processing, when the major axis of the first lower hole is equal to or greater than a predetermined value, the first lower hole is laminated and processed such that the line with the angle θ less than 45 degrees is longer than the line with the angle θ greater than or equal to 45 degrees. When the major axis of the first lower hole is less than the predetermined value, the first lower hole is laminated and processed such that the cross section in the direction orthogonal to the depth direction of the first lower hole is circular.

[0012] In an example of the present disclosure, the first lower hole has an insertion port for a tap, and the diameter of the insertion port becomes shorter as it is farther from the insertion side of the tap.

[0013] In an example of the present disclosure, the additional processing method further includes a step of drilling the first lower hole and a step of tapping the first lower hole that has been drilled.

[0014] In another example of the present disclosure, an additional processing apparatus is provided. The additional processing apparatus includes a recoater for spreading a metal powder material in a processing area of a workpiece, a lifting mechanism configured to be able to raise and lower the floor surface of the processing area, a plate configured to be detachable from the floor surface, an irradiation mechanism capable of performing laminated processing of the workpiece by irradiating a laser beam onto the metal powder material spread in the processing area, a control unit capable of performing laminated processing of a workpiece having a predetermined shape in the processing area by repeating the supply of the metal powder material to the processing area by the recoater, the lowering of the floor surface by the lifting mechanism, and the irradiation of the laser beam by the irradiation mechanism. The workpiece having the predetermined shape includes a first lower hole to be tapped. The control unit laminates and processes the first lower hole such that the depth direction of the first lower hole is inclined with respect to the lamination direction of the workpiece, and in a cross-sectional view of the first lower hole in the direction orthogonal to the depth direction, when the angle of inclination of the tangent line on the upper half line of the first lower hole with respect to the lamination direction is defined as the angle θ, the first lower hole is laminated and processed such that the line with the angle θ less than a predetermined angle is longer than the line with the angle θ greater than or equal to the predetermined angle.

[0015] In other examples of the present disclosure, an additional processing program for the workpiece is provided. The additional processing program causes a computer to perform steps of lowering the floor surface of the processing area of the workpiece, spreading a metal powder material in the processing area after lowering the floor surface of the processing area, irradiating a laser beam onto the metal powder material spread in the processing area, repeating the steps of lowering, spreading, and irradiating to perform a step of laminating a workpiece of a predetermined shape in the processing area. The workpiece of the predetermined shape includes a first counterbore that is to be tapped. The laminating step includes laminating the first counterbore such that the depth direction of the first counterbore is inclined with respect to the lamination direction of the workpiece, and in a sectional view of the first counterbore in a direction orthogonal to the depth direction, when an angle formed by a tangent line on the upper half line of the first counterbore with respect to the lamination direction is defined as an angle θ, the laminating step of the first counterbore is performed such that a line where the angle θ is less than a predetermined angle is longer than a line where the angle θ is greater than or equal to the predetermined angle.

[0016] The above and other objects, features, aspects, and advantages of the present invention will become apparent from the following detailed description of the present invention, which is to be understood in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0017]

Figure 1

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Embodiments for Carrying Out the Invention

[0018] Hereinafter, each embodiment according to the present invention will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. Note that each embodiment and each modification described below may be selectively combined as appropriate.

[0019] <A. Additional Processing Device 100> First, with reference to FIG. 1, an additional processing device 100 according to an embodiment will be described. FIG. 1 is a view showing an example of the device configuration of the additional processing device 100.

[0020] For convenience of explanation, hereinafter, the vertical direction is also referred to as the "Z-axis direction". Also, the downward direction corresponding to the direction of gravity is also referred to as the positive side in the Z-axis direction, and the upward direction is also referred to as the negative side in the Z-axis direction.

[0021] Also, the direction on the horizontal plane perpendicular to the Z-axis direction is also referred to as the "X-axis direction". The X-axis direction corresponds to the left-right direction when viewing the additive manufacturing apparatus 100 from the front. Also, the right direction when viewing the additive manufacturing apparatus 100 from the front is also referred to as the positive side of the X-axis direction, and the left direction when viewing the additive manufacturing apparatus 100 from the front is also referred to as the negative side of the X-axis direction.

[0022] Furthermore, the direction on the horizontal plane perpendicular to both the X-axis direction and the Z-axis direction is also referred to as the "Y-axis direction". In FIG. 1, the Y-axis direction indicates the front-back direction of the paper. Also, the back side when viewing the additive manufacturing apparatus 100 from the front side is also referred to as the positive side of the Y-axis direction, and the front side of the additive manufacturing apparatus 100 is also referred to as the negative side of the Y-axis direction.

[0023] The additive manufacturing apparatus 100 is a processing machine capable of performing layer processing of a workpiece by the SLM method. The additive manufacturing apparatus 100 irradiates a laid metal powder material with laser light, and locally melts and solidifies the metal powder material to perform layer processing of the workpiece.

[0024] The additive manufacturing apparatus 100 includes a lifting mechanism 130, a lifting mechanism 140, a recoater 150, and a laser irradiation mechanism 160.

[0025] Also, inside the additive manufacturing apparatus 100, a storage area AR1 for the metal powder material PM is provided. The metal powder material PM is the material of the workpiece W. Any metal powder that can be melted by the laser light LS can be adopted for the metal powder material PM.

[0026] The storage area AR1 is partitioned and formed, for example, by the lifting mechanism 130 and the wall surface 132. The wall surface 132 is configured to surround the upper surface of the lifting mechanism 130 in a top view.

[0027] The upper surface of the lifting mechanism 130 forms the floor surface of the storage area AR1. Also, the upper surface of the lifting mechanism 130 is configured to be movable up and down in the Z-axis direction. The lifting of the lifting mechanism 130 is realized, for example, by a motor 212Z (see FIG. 10) described later. The upper part of the storage area AR1 is open, and when the lifting mechanism 130 ascends, the metal powder material PM is pushed out from the storage area AR1.

[0028] Also, inside the additional processing device 100, a processing area AR2 for the workpiece W is provided. The processing area AR2 is partitioned and formed, for example, by a lifting mechanism 140 and a wall surface 142. The wall surface 142 is configured to surround the upper surface of the lifting mechanism 140 in a top view.

[0029] The upper surface of the lifting mechanism 140 forms the floor surface of the processing area AR2. Also, the lifting mechanism 140 is configured to be movable up and down in the Z-axis direction. The lifting of the lifting mechanism 140 is realized, for example, by a motor 222Z (see FIG. 10) described later. The upper part of the processing area AR2 is open.

[0030] A base plate 144 can be mounted on the upper surface of the lifting mechanism 140. The base plate 144 can be fixed to the lifting mechanism 140, for example, by a chuck mechanism (not shown). The base plate 144 is fixed to the lifting mechanism 140 before the start of the additive manufacturing by the additive processing device 100.

[0031] The recoater 150 is configured to spread the metal powder material PM pushed out from the storage area AR1 over the processing area AR2. The recoater 150 is composed of a blade or a roller, etc.

[0032] More specifically, the recoater 150 extends in the Y-axis direction. The width of the recoater 150 in the Y-axis direction is longer than the width of the storage area AR1 in the Y-axis direction and longer than the width of the processing area AR2 in the Y-axis direction.

[0033] Further, the recoater 150 is configured to be drivable in the X-axis direction. The driving of the recoater 150 is realized, for example, by a motor 232X (see FIG. 10) described later. The recoater 150 is configured to be at least passable through a storage area AR1 and a processing area AR2 in a top view. When the recoater 150 is driven in the negative X-axis direction, the metal powder material PM extruded from the upper surface of the storage area AR1 is conveyed to the processing area AR2. Thereby, the metal powder material PM is supplied from the storage area AR1 to the processing area AR2.

[0034] The laser irradiation mechanism 160 irradiates the laser light LS onto the metal powder material PM spread in the processing area AR2, and selectively melts and solidifies the metal powder material PM. As an example, the laser irradiation mechanism 160 is composed of a laser oscillator, an optical system, and a laser scanner.

[0035] The laser oscillator is a device that generates high-energy laser light. The optical system condenses the laser light generated by the laser oscillator to generate the laser light LS. For the laser scanner, for example, a galvanometer scanner is used. The galvanometer scanner is composed of a galvanometer mirror for deflecting the laser light LS in the X-axis direction and a galvanometer mirror for deflecting the laser light LS in the Y-axis direction. The additive processing apparatus 100 irradiates the laser light LS at an arbitrary position on the XY plane by controlling the driving of the two galvanometer mirrors.

[0036] <B. Laminated Processing Step> Next, with reference to FIG. 2, the laminated processing step of the SLM method will be described. FIG. 2 is a diagram showing the laminated processing step of the SLM method in chronological order.

[0037] In step S1, the additive processing apparatus 100 raises the elevating mechanism 130. The raising width of the elevating mechanism 130 is preset. When the elevating mechanism 130 rises, the metal powder material PM is extruded from the storage area AR1.

[0038] Further, the additive processing apparatus 100 lowers the elevating mechanism 140. The lowering width of the elevating mechanism 140 is preset. The lowering width corresponds to the thickness of one layer of the workpiece W. Thereby, a space where the metal powder material PM does not exist is formed in the processing area AR2.

[0039] In step S2, the additive processing apparatus 100 drives the recoater 150, which is waiting at a predetermined position, in the negative X-axis direction. At this time, the additive processing apparatus 100 drives the recoater 150 so that the recoater 150 passes through the storage area AR1 and the processing area AR2 in order in a top view. Thereby, the recoater 150 evenly spreads the metal powder material PM extruded from the storage area AR1 over the processing area AR2. Thereafter, the additive processing apparatus 100 returns the recoater 150 to a predetermined standby position.

[0040] In step S3, the additive processing apparatus 100 controls the laser irradiation mechanism 160 according to the additive processing program and irradiates the laser light LS onto the metal powder material PM spread over the processing area AR2. At this time, the laser light LS is irradiated onto the metal powder material PM on the base plate 144. The metal powder material PM at the irradiated portion of the laser light LS melts and solidifies. Thereby, the first layer SL1 of the workpiece W is formed.

[0041] Thereafter, the additive processing apparatus 100 repeats the processes of steps S1 to S3 to form a workpiece W with a predetermined shape on the base plate 144 mounted on the floor surface of the processing area AR2.

[0042] <C. Overview> In the post-process of the laminated processing shown in FIG. 2, tapping may be performed. Tapping is a process of forming a female thread on the workpiece W. If the cutting amount in tapping is large, the amount of chips will increase. Also, the wear of cutting tools such as drill tools and tap tools will progress. Therefore, the additional processing device 100 according to the embodiment pre-forms a pilot hole at a location where tapping is planned. By pre-forming the pilot hole during the laminated processing, the cutting amount during the subsequent tapping process is reduced. As a result, the wear of the cutting tool can be suppressed.

[0043] Hereinafter, with reference to FIGS. 3 to 5, an outline of the laminated processing method according to the embodiment will be described. FIG. 3 is a view showing an example of a workpiece W shaped by laminated processing from the negative side in the Y-axis direction. FIG. 4 is a view showing an example of a workpiece W shaped by laminated processing from the negative side in the Z-axis direction.

[0044] In the examples of FIGS. 3 and 4, pilot holes PH1 and PH2 where tapping is planned are formed in the workpiece W. Here, the additional processing device 100 according to the embodiment makes the shapes during lamination different between the pilot hole PH1 with a depth direction inclined with respect to the lamination direction and the pilot hole PH2 with a depth direction parallel to the lamination direction. Note that the pilot hole PH1 may be laminated so that the depth direction is orthogonal to the lamination direction, or may be laminated so that the angle formed by the depth direction and the lamination direction is greater than 0 degrees and less than 90 degrees. In the example of FIG. 3, the pilot hole PH1 is laminated so that the depth direction is orthogonal to the lamination direction.

[0045] FIG. 5 is a view showing the outer shape of the pilot hole PHX according to the comparative example and the outer shape of the pilot hole PH1 from their depth directions. The lamination direction LD shown in FIG. 5 corresponds to the negative side in the Z-axis direction. Also, the boundary line L1 shown in FIG. 5 indicates the line of the upper half of the pilot hole in a cross-sectional view in the direction orthogonal to the depth direction of the pilot hole. The boundary line L1 corresponds to the boundary between the irradiated portion and the non-irradiated portion of the laser beam LS. Further, the tangent line TL shown in FIG. 5 indicates the tangent line to the boundary line L1. Hereinafter, the angle at which the tangent line TL is inclined with respect to the lamination direction LD will be defined as the inclination angle θ.

[0046] The hollow portion of the lower hole PHX has a cylindrical shape. As the lamination of the lower hole PHX progresses, the inclination angle θ increases. When the inclination angle θ increases, the proportion of the solidified portion at the boundary line L1 supported by the metal powder material PM increases. Therefore, at the location where the inclination angle θ is large, the solidified portion is likely to collapse.

[0047] Therefore, the additive processing apparatus 100 according to the embodiment performs the lamination process so that the boundary line L1 where the inclination angle θ is less than a predetermined angle is longer than the circular lower hole PHX. In other words, the additive processing apparatus 100 performs the lamination process so that the boundary line L1 where the inclination angle θ is less than a predetermined angle is longer than the boundary line L1 where the inclination angle θ is greater than or equal to the predetermined angle. Thereby, it becomes difficult for collapse to occur at the boundary line L1. The above-mentioned predetermined angle is, for example, 45 degrees.

[0048] As an example, the additive processing apparatus 100 performs the lamination process so that the shape of the lower hole in a cross-sectional view in the direction orthogonal to the depth direction is an elliptical shape or a teardrop shape. In the example of FIG. 5, the lower hole PH1 whose cross-sectional shape is an elliptical shape is shown. The long side of the elliptical shape is parallel to the lamination direction LD, and the short side of the elliptical shape is parallel to the horizontal direction.

[0049] Regarding the lower hole PH1 with an elliptical cross-section, at the position P1 corresponding to the height H, the inclination angle θ is "θ1". On the other hand, regarding the lower hole PHX with a circular cross-section, at the position PX corresponding to the height H, the inclination angle θ is "θX". Here, "θX" is larger than "θ1". Therefore, in the lower hole PH1 with an elliptical cross-section, compared with the lower hole PHX with a circular cross-section, it is less likely for collapse to occur at the boundary line L1.

[0050] Referring again to FIGS. 3 and 4, for the counterbore PH2 whose depth direction is parallel to the lamination direction LD, collapse at the boundary line L1 is less likely to occur. Therefore, for such a counterbore PH2, the additive processing device 100 performs lamination processing so that the cross-section in the direction orthogonal to the lamination direction LD is circular. As a result, the additive processing device 100 can increase the volume of the hollow portion of the counterbore PH2. Consequently, the cutting amount can be reduced during the subsequent tapping process.

[0051] <D. Cross-sectional shape of the counterbore PH1> Next, referring to FIG. 6, the cross-sectional shape of the counterbore PH1 shown in FIG. 3 will be described. FIG. 6 is a view showing the cross-section of the counterbore PH1 along the line VI-VI shown in FIG. 3 from the positive side in the Z-axis direction.

[0052] As shown in FIG. 6, the counterbore PH1 is composed of an insertion port PH1A of a tap tool and a counterbore portion PH1B continuous from the insertion port PH1A. The additive processing device 100 performs lamination processing on the counterbore PH1 so that the diameter of the insertion port PH1A becomes shorter as it moves away from the insertion side of the tap tool. As a result, the counterbore PH1 is shaped with a chamfer. Consequently, the insertion port PH1A functions as a guide for the tap tool, making it easier for the tap tool to be inserted into the counterbore PH1.

[0053] In the example of FIG. 6, the diameter of the opening side at the insertion port PH1A is indicated by "ΔR1A", and the diameter of the insertion port PH1A on the side opposite to the opening side is indicated by "ΔR1B". The "ΔR1B" is also the diameter of the counterbore portion PH1B. "ΔR1A" is longer than "ΔR1B". Preferably, "ΔR1A" is longer than the diameter of the tap tool. On the other hand, "ΔR1B" is shorter than the diameter of the tap tool.

[0054] Note that FIG. 6 shows an example where the shape of the insertion port PH1A is a linear taper, but the shape of the insertion port PH1A is not limited to this. As an example, the shape of the insertion port PH1A may be an exponential function taper or a parabolic taper.

[0055] <Cross-sectional shape of the lower hole PH2> Next, with reference to FIG. 7, the cross-sectional shape of the lower hole PH2 shown in FIG. 3 will be described. FIG. 7 is a view showing the cross-section of the lower hole PH2 along VII-VII shown in FIG. 3 from the negative side in the Y-axis direction.

[0056] As shown in FIG. 7, the lower hole PH2 is composed of an insertion port PH2A for the tap tool and a lower hole portion PH2B continuous from the insertion port PH2A. The additional processing device 100 laminates the lower hole PH2 such that the diameter of the insertion port PH2A becomes shorter as it moves away from the insertion side of the tap tool. As a result, the lower hole PH2 is shaped with a chamfered state. Consequently, the insertion port PH2A functions as a guide for the tap tool, making it easier for the tap tool to be inserted into the lower hole PH2.

[0057] In the example of FIG. 7, the diameter of the insertion port PH2A on the opening side is indicated by "ΔR2A", and the diameter of the insertion port PH2A on the side opposite to the opening side is indicated by "ΔR2B". The "ΔR2B" is also the diameter of the lower hole portion PH2B. "ΔR2A" is longer than "ΔR2B". Preferably, "ΔR2A" is longer than the diameter of the tap tool. On the other hand, "ΔR2B" is shorter than the diameter of the tap tool.

[0058] Although FIG. 7 shows an example where the shape of the insertion port PH2A is a linear taper, the shape of the insertion port PH2A is not limited to this. As an example, the shape of the insertion port PH2A may be an exponential function taper or a parabolic taper.

[0059] <Laminating process of the lower hole PH1> Next, with reference to FIGS. 8 and 9, the lamination processing step of the above-described lower hole PH1 (see FIG. 3) will be described. FIG. 8 is a view showing the lamination processing step of the lower hole PH1 in chronological order from the negative side in the Y-axis direction. FIG. 9 is a view showing the lamination processing step of the lower hole PH1 in chronological order from the negative side in the Z-axis direction.

[0060] In step S11, the additive processing apparatus 100 repeatedly executes the lamination processing steps S1 to S3 described with reference to FIG. 2 above. As a result, layers SL1 to SL3 are sequentially formed. At this time, when laminating layer SL3, the additive processing apparatus 100 does not irradiate the laser beam LS on the portion of the counterbore PH1. As a result, the metal powder material PM remains as it is in the non-irradiated portion of the laser beam LS, and the metal powder material PM melts and solidifies in the irradiated portion of the laser beam LS.

[0061] In step S12, the additive processing apparatus 100 further repeatedly executes the lamination processing steps S1 to S3 described with reference to FIG. 2 above. As a result, layers SL4 to SL9 are sequentially formed. When forming layers SL4 to SL9, the additive processing apparatus 100 does not irradiate the laser beam LS on the portion of the counterbore PH1, and irradiates the laser beam LS on the portions other than the counterbore PH1. As a result, the metal powder material PM remains as it is in the non-irradiated portion of the laser beam LS, and the metal powder material PM melts and solidifies in the irradiated portion of the laser beam LS.

[0062] In step S13, the additive processing apparatus 100 further repeatedly executes the lamination processing steps S1 to S3 described with reference to FIG. 2 above. As a result, layers SL10 to SL14 are sequentially formed. When forming layers SL10 to SL12, the additive processing apparatus 100 does not irradiate the laser beam LS on the portion of the counterbore PH1, and irradiates the laser beam LS on the portions other than the counterbore PH1. As a result, the metal powder material PM remains as it is in the non-irradiated portion of the laser beam LS, and the metal powder material PM melts and solidifies in the irradiated portion of the laser beam LS.

[0063] As described above, a counterbore PH1 having an elliptical cross-section is formed in the workpiece W. The metal powder material PM in the counterbore PH1 is removed by an air ejection mechanism (not shown) or the like.

[0064] <G. Drive mechanism of additive processing apparatus 100> Next, referring to FIG. 10, the drive mechanism in the additional processing apparatus 100 will be described. FIG. 10 is a diagram showing an example of the drive mechanism of the additional processing apparatus 100.

[0065] As shown in FIG. 10, the additional processing apparatus 100 includes a control unit 50, the above-described elevating mechanisms 130 and 140, the above-described reclaimer 150, the above-described laser irradiation mechanism 160, and drive units 210, 220, 230, and 240.

[0066] The control unit 50 controls various devices within the additional processing apparatus 100. The device configuration of the control unit 50 is arbitrary. The control unit 50 may be composed of a single control unit or a plurality of control units. As an example, the control unit 50 includes at least one of a CNC (Computer Numerical Control) and a PLC (Programmable Logic Controller).

[0067] The drive unit 210 is a drive mechanism for driving the above-described elevating mechanism 130. The drive unit 210 may be composed of a single drive unit or a plurality of drive units. In the example of FIG. 10, the drive unit 210 is composed of a motor driver 211Z and a motor 212Z.

[0068] The motor driver 211Z sequentially receives an input of a target position related to the elevating mechanism 130 from the control unit 50 and outputs a current corresponding to the target position to the motor 212Z. Thereby, the motor 212Z moves the elevating mechanism 130 to an arbitrary position in the Z-axis direction. The motor 212Z may be an AC motor, a stepping motor, a servo motor, or other types of motors.

[0069] The drive unit 220 is a drive mechanism for driving the above-described elevating mechanism 140. The drive unit 220 may be composed of a single drive unit or a plurality of drive units. In the example of FIG. 10, the drive unit 220 is composed of a motor driver 221Z and a motor 222Z.

[0070] The motor driver 221Z sequentially receives an input of a target position related to the lifting mechanism 140 from the control unit 50, and outputs a current corresponding to the target position to the motor 222Z. Thereby, the motor 222Z moves the lifting mechanism 140 to an arbitrary position in the Z-axis direction. The motor 222Z may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0071] The drive unit 230 is a drive mechanism for driving the above-described recorder 150. The drive unit 230 may be composed of a single drive unit or a plurality of drive units. In the example of FIG. 10, the drive unit 230 is composed of a motor driver 231X and a motor 232X.

[0072] The motor driver 231X sequentially receives an input of a target position related to the recorder 150 from the control unit 50, and outputs a current corresponding to the target position to the motor 232X. Thereby, the motor 232X moves the recorder 150 to an arbitrary position in the X-axis direction. The motor 232X may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0073] The drive unit 240 is a drive mechanism for rotationally driving the galvanometer mirrors 162A and 162B in the laser irradiation mechanism 160. The drive unit 240 may be composed of a single drive unit or a plurality of drive units. In the example of FIG. 10, the drive unit 240 is composed of motor drivers 241A and 241B and motors 242A and 242B.

[0074] The motor driver 241A sequentially receives from the control unit 50 an input of the target rotation angle or the target rotation speed of the galvanometer mirror 162A centered on the X-axis direction, and outputs a current corresponding to the target rotation angle or the target rotation speed to the motor 242A. The motor 242A drives the galvanometer mirror 162A to swing around the X-axis direction. The additional processing device 100 can irradiate the laser beam LS at an arbitrary position in the X-axis direction by reflecting the laser beam LS generated by the laser irradiation mechanism 160 with the galvanometer mirror 162A. The laser beam LS reflected by the galvanometer mirror 162A is guided to the galvanometer mirror 162B.

[0075] The motor driver 241B sequentially receives from the control unit 50 an input of the target rotation angle or the target rotation speed of the galvanometer mirror 162B centered on the Y-axis direction, and outputs a current corresponding to the target rotation angle or the target rotation speed to the motor 242B. The motor 242B drives the galvanometer mirror 162B to swing around the Y-axis direction. The additional processing device 100 can irradiate the laser beam LS at an arbitrary position in the Y-axis direction by reflecting the laser beam LS generated by the laser irradiation mechanism 160 with the galvanometer mirror 162B.

[0076] <H. Hardware Configuration of Control Unit 50> Next, with reference to FIG. 11, the hardware configuration of the control unit 50 shown in FIG. 10 will be described. FIG. 11 is a diagram showing an example of the hardware configuration of the control unit 50.

[0077] As described above, the control unit 50 may be a CNC or a PLC. FIG. 11 shows the hardware configuration of the control unit 50 as a CNC.

[0078] The control unit 50 includes, for example, a control circuit 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a communication interface 104, and an auxiliary storage device 120. These components are connected to an internal bus 109.

[0079] The control circuit 101 is constituted by, for example, at least one integrated circuit. The integrated circuit can be constituted by, for example, at least one CPU (Central Processing Unit), at least one GPU (Graphics Processing Unit), at least one ASIC (Application Specific Integrated Circuit), at least one FPGA (Field Programmable Gate Array), or a combination thereof.

[0080] The control circuit 101 controls the operation of the control unit 50 by executing various programs such as the additional processing program 122. The additional processing program 122 is a program for realizing the various processes described in this specification. Based on receiving an execution instruction of the additional processing program 122, the control circuit 101 reads the additional processing program 122 from the ROM 102 into the RAM 103. The RAM 103 functions as a working memory and temporarily stores various data necessary for the execution of the additional processing program 122.

[0081] The communication interface 104 is an interface for realizing communication with various devices. The additional processing device 100 communicates with various drive units (for example, the above-described drive units 210, 220, 230, 240, etc.) for realizing the additional processing of the workpiece via the communication interface 104, for example.

[0082] The auxiliary storage device 120 is a storage medium such as a hard disk or a flash memory, for example. The auxiliary storage device 120 stores the additional processing program 122, the three-dimensional data 124, etc. The additional processing program 122 is generated in advance from the three-dimensional data 124 of the workpiece W, for example. The additional processing device 100 executes the additional processing program 122 to shape the workpiece W having the shape shown in the three-dimensional data 124.

[0083] Note that the storage locations of the additional processing program 122 and the three-dimensional data 124 are not limited to the auxiliary storage device 120, and may be stored in the storage area of the control circuit 101 (for example, cache memory), ROM 102, RAM 103, an external device (for example, a server), or the like.

[0084] Also, the additional processing program 122 may be provided incorporated into a part of an arbitrary program instead of as a single program. In this case, various processes according to the present embodiment are realized in cooperation with an arbitrary program. Even a program that does not include such a part of the module does not deviate from the gist of the additional processing program 122 according to the present embodiment. Further, part or all of the functions provided by the additional processing program 122 may be realized by dedicated hardware. Further, the control unit 50 may be configured in a form such as a so-called cloud service in which at least one server executes a part of the processing of the additional processing program 122.

[0085] <I. Flow related to layer processing> Next, with reference to FIG. 12, the control flow of the additional processing apparatus 100 will be described. FIG. 12 is a flowchart showing the flow of the layer processing by the additional processing apparatus 100.

[0086] The process shown in FIG. 12 is realized, for example, when the control unit 50 of the additional processing apparatus 100 executes the above-described additional processing program 122. In other aspects, part or all of the process may be executed by circuit elements or other hardware.

[0087] In step S110, the control unit 50 initializes a variable “N” for managing the number of layers of the workpiece W. “N” is a natural number. The initial value of “N” is “1”.

[0088] In step S112, the control unit 50 raises the above-described elevating mechanism 130. The raising width of the elevating mechanism 130 is preset. As a result, the metal powder material PM is pushed out from the storage area AR1.

[0089] In step S114, the control unit 50 lowers the above-described elevating mechanism 140. The lowering width of the elevating mechanism 140 is preset. The lowering width corresponds to the thickness of one layer of the workpiece W. Thereby, a space where the metal powder material PM does not exist is formed in the processing area AR2.

[0090] In step S116, the control unit 50 drives the recoater 150, which is waiting at a predetermined position, in the negative X-axis direction. At this time, the control unit 50 drives the recoater 150 so that the recoater 150 passes through the storage area AR1 and the processing area AR2 in order in a top view. Thereby, the metal powder material PM is supplied from the storage area AR1 to the processing area AR2. Thereafter, the control unit 50 returns the recoater 150 to a predetermined standby position.

[0091] In step S118, the control unit 50 controls the laser irradiation mechanism 160 according to the additional processing program 122, and irradiates the laser beam LS onto the metal powder material PM spread in the processing area AR2. At this time, for the counterbore PH1 whose depth direction is inclined with respect to the stacking direction of the workpiece, the control unit 50 performs stacking processing so that the cross section becomes non-circular. On the other hand, for the counterbore PH2 whose depth direction is parallel to the stacking direction of the workpiece, the control unit 50 performs stacking processing so that the cross section becomes circular. Since the stacking methods of the counterbores PH1 and PH2 are as described above, the description thereof will not be repeated.

[0092] In step S120, the control unit 50 determines whether or not a predetermined end condition is satisfied. As an example, the end condition is satisfied when the variable "N" is equal to or greater than a predetermined value. When the control unit 50 determines that the predetermined end condition is satisfied (YES in step S120), the control unit 50 ends the process shown in FIG. 12. Otherwise (NO in step S120), the control unit 50 switches the control to step S122.

[0093] In step S122, the control unit 50 increments "N". That is, the control unit 50 adds 1 to "N". Thereafter, the control unit 50 returns the process to step S112.

[0094] <J. Flow related to post-process> Next, with reference to FIG. 13, the control flow of the post-process of the lamination process shown in FIG. 12 will be described. FIG. 13 is a flowchart showing the flow of the tapping process in the post-process.

[0095] The tapping process in the post-process is performed, for example, on the pilot holes PH1 and PH2 formed by the additional processing device 100. The tapping process in the post-process may be executed by the additional processing device 100 or may be executed by a machine tool different from the additional processing device 100. Hereinafter, the description will be made on the premise that the tapping process is executed by a machine tool different from the additional processing device 100. Further, hereinafter, when the pilot holes PH1 and PH2 are not particularly distinguished, the pilot holes PH1 and PH2 are also referred to as pilot hole PH.

[0096] The machine tool includes a spindle. Various tools can be mounted on the spindle. The spindle is configured to be rotatable in its axial direction with a tool mounted thereon. The machine tool performs removal processing by applying the rotating tool to the workpiece.

[0097] In step S210, the machine tool mounts a drill tool on the spindle and performs drilling on the pilot hole PH formed by the additional processing device 100. At this time, the machine tool inserts the drill tool into the pilot hole PH with the rotation axis of the drill tool and the depth direction of the pilot hole PH overlapping. The diameter of the drill tool is shorter than the above-described diameter ΔR1A (see FIG. 6) and the above-described diameter ΔR2A (see FIG. 7). Further, the diameter of the drill tool is longer than the above-described diameter ΔR1B (see FIG. 6) and the above-described diameter ΔR2B (see FIG. 7).

[0098] Next, in step S220, the machine tool attaches a tap tool to the spindle and performs drilling on the pilot hole PH formed by the additive processing device 100. At this time, the machine tool inserts the tap tool into the pilot hole PH with the rotation axis of the tap tool and the depth direction of the pilot hole PH overlapping. The diameter of the tap tool is shorter than the above-described diameter ΔR1A (see FIG. 6) and the above-described diameter ΔR2A (see FIG. 7). Also, the diameter of the tap tool is longer than the above-described diameter ΔR1B (see FIG. 6) and the above-described diameter ΔR2B (see FIG. 7).

[0099] <K. Others> In the above description, for the pilot hole PH1 (see FIG. 3) whose depth direction is inclined with respect to the stacking direction of the workpiece, the additive processing device 100 performs stacking processing so that the cross section becomes non-circular regardless of the diameter of the pilot hole PH1. However, the cross-sectional shape of the pilot hole PH1 may be changed according to its diameter.

[0100] As an example, when the major axis of the pilot hole PH1 is equal to or greater than a predetermined value, the additive processing device 100 shapes the pilot hole PH1 so that the cross section becomes non-circular. The major axis corresponds to, for example, the diameter ΔR1B (see FIG. 6) of the pilot hole PH1 in the stacking direction.

[0101] More specifically, when the major axis of the pilot hole PH1 is equal to or greater than a predetermined value, the additive processing device 100 performs stacking processing on the pilot hole PH1 so that the boundary line L1 where the above-described inclination angle θ (see FIG. 5) is less than 45 degrees becomes longer than the boundary line L1 where it is 45 degrees or more. As an example, the additive processing device 100 shapes the pilot hole PH1 having an elliptical or teardrop-shaped cross section.

[0102] On the other hand, when the major axis of the pilot hole PH1 is less than a predetermined value, the additive processing device 100 shapes the pilot hole PH1 so that the cross section becomes circular. That is, in this case, the additive processing device 100 shapes the pilot hole PH1 similar to the pilot hole PH2 (see FIG. 3).

[0103] The shorter the diameter of the lower hole PH1, the greater the load on the tool in the subsequent process. However, in this example, when the diameter of the lower hole PH1 is short, the lower hole PH1 with a circular cross-section is shaped. This can suppress the load on the tool in the subsequent process and suppress tool wear and tool breakage.

[0104] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Signs

[0105] 50 Control unit, 100 Additional processing device, 101 Control circuit, 102 ROM, 103 RAM, 104 Communication interface, 109 Internal bus, 120 Auxiliary storage device, 122 Additional processing program, 124 Three-dimensional data, 130 Lifting mechanism, 132 Wall surface, 140 Lifting mechanism, 142 Wall surface, 144 Base plate, 150 Recoater, 160 Laser irradiation mechanism, 162A Galvano mirror, 162B Galvano mirror, 210 Drive unit, 211Z Motor driver, 212Z Motor, 220 Drive unit, 221Z Motor driver, 222Z Motor, 230 Drive unit, 231X Motor driver, 232X Motor, 240 Drive unit, 241A Motor driver, 241B Motor driver, 242A Motor, 242B Motor, AR1 Storage area, AR2 Processing area, H Height, L1 Boundary line, LD Lamination direction, LS Laser beam, PH Lower hole, PH1 Lower hole, PH1A Insertion port, PH1B Lower hole part, PH2 Lower hole, PH2A Insertion port, PH2B Lower hole part, PHX Lower hole, PM Metal powder material, SL1~SL14 Layers, TL Tangent line, W Workpiece, ΔR1A Diameter, ΔR1B Diameter, ΔR2A Diameter, ΔR2B Diameter, θ Tilt angle.

Claims

1. A method for additive machining of a workpiece, comprising: A step of lowering a floor surface of a workpiece processing area; After lowering the floor surface of the processing area, spreading a metal powder material in the processing area; Irradiating the metal powder material spread in the processing area with a laser beam; The method further comprises repeating the lowering step, the laying step, and the irradiating step to laminate a workpiece having a predetermined shape in the processing area, The workpiece of a predetermined shape includes a first pilot hole to be tapped; The first pilot hole is The lamination process is performed such that the depth direction of the first pilot hole is inclined with respect to the lamination direction of the workpiece, The additive processing method includes stacking processing such that the first pilot hole has an elliptical or teardrop shape in a cross-sectional view of the first pilot hole in a direction perpendicular to the depth direction.

2. The workpieces laminated in the lamination step include a second pilot hole to be tapped, The second pilot hole is The lamination process is performed so that the depth direction of the second pilot hole is parallel to the lamination direction, The additive processing method according to claim 1 , wherein the lamination processing is performed so that a cross section in a direction perpendicular to the lamination direction has a circular shape.

3. In the lamination step, When the major axis of the first pilot hole is equal to or larger than a predetermined value, the first pilot hole is laminated so that the shape of the first pilot hole is an ellipse or a teardrop shape in the cross-sectional view, The additional machining method according to claim 1 or 2, wherein, when the major axis of the first pilot hole is less than the predetermined value, the first pilot hole is laminated so that the shape of the first pilot hole becomes circular when viewed in cross section.

4. The first pilot hole has an insertion opening for a tap, The additional machining method according to claim 1 or 2, wherein the diameter of the insertion hole decreases as it moves away from the insertion side of the tap.

5. The additive processing method further comprises: Drilling the first pilot hole; The method for additional machining according to claim 1 or 2, further comprising the step of tapping the first pilot hole that has been drilled.

6. A recoater for laying metal powder material on the processing area of ​​the workpiece; A lifting mechanism configured to be able to lift and lower a floor surface of the processing area; A plate configured to be detachable from the floor surface; an irradiation mechanism capable of performing layered processing of the workpiece by irradiating a laser beam onto the metal powder material spread in the processing area; a control unit capable of laminating a workpiece having a predetermined shape in the processing area by repeating the supply of metal powder material to the processing area by the recoater, the lowering of the floor surface by the lifting mechanism, and the irradiation of laser light by the irradiation mechanism; The workpiece of a predetermined shape includes a first pilot hole to be tapped; The control unit is The first pilot hole is laminated so that a depth direction of the first pilot hole is inclined with respect to a lamination direction of the workpiece, an additional processing device that performs additive processing on the first pilot hole so that the shape of the first pilot hole becomes elliptical or teardrop-shaped when viewed in cross section of the first pilot hole in a direction perpendicular to the depth direction.

7. A program for additive machining of a workpiece, The additive processing program is configured to: A step of lowering a floor surface of a workpiece processing area; After lowering the floor surface of the processing area, spreading a metal powder material in the processing area; Irradiating the metal powder material spread in the processing area with a laser beam; repeating the step of lowering, the step of laying, and the step of irradiating, thereby executing a step of laminating a workpiece having a predetermined shape in the processing area; The workpiece of a predetermined shape includes a first pilot hole to be tapped; The lamination step includes: The first pilot hole is laminated so that a depth direction of the first pilot hole is inclined with respect to a lamination direction of the workpiece, an additive machining program including a step of additively machining the first pilot hole so that the shape of the first pilot hole becomes elliptical or teardrop-shaped in a cross-sectional view of the first pilot hole in a direction perpendicular to the depth direction.

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