Additive processing method, additive processing apparatus, and additive processing program

Abstract

This technology improves the accuracy of creating pilot holes for tapping compared to conventional methods. [Solution] The additive processing method comprises the steps of lowering the floor surface of the processing area, spreading metal powder material in the processing area after lowering the floor surface of the processing area, irradiating the metal powder material spread in the processing area with laser light, and repeating the steps of lowering, spreading, and irradiating to laminate a workpiece of a predetermined shape in the processing area. The workpiece includes a first pilot hole that is to be tapped. The first pilot hole is laminated such that its depth direction is inclined with respect to the lamination direction, and in a cross-sectional view in the direction perpendicular to the depth direction, if the angle at which the tangent line of the upper half of the first pilot hole is inclined with respect to the lamination direction is defined as angle θ, the lamination is performed such that the line with an angle θ less than a predetermined angle is longer than the line with an angle θ greater than or equal to a predetermined angle.

Description

Technical Field

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

Background Art

[0002] Japanese Patent Application Laid-Open 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 metal powder material spread over a processing area with laser light 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 subsequent 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 subsequent process, a pilot hole may be pre-formed during the layered processing of the workpiece. When forming the pilot hole, the laser light 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 shaping accuracy of a pilot hole for tapping more than before. [Means for solving the problem]

[0007] One example of the present disclosure provides a method for additional processing of a workpiece. The additional processing method comprises the steps of: lowering the floor surface of the workpiece processing area; after lowering the floor surface of the processing area, spreading metal powder material in the processing area; irradiating the metal powder material spread in the processing area with laser light; and repeating the lowering step, the spreading step, and the irradiating step to stack a workpiece of a predetermined shape in the processing area. The workpiece of the predetermined shape includes a first pilot hole that is to be tapped. The first pilot hole is stacked such that the depth direction of the first pilot hole is inclined with respect to the stacking direction of the workpiece, and when the angle θ is the angle at which the tangent line of the upper half of the first pilot hole is inclined with respect to the stacking direction in a cross-sectional view of the first pilot hole in a direction perpendicular to the depth direction, the stacking is performed such that the 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 specified angle is 45 degrees.

[0009] In one example of this disclosure, the shape of the first pilot hole in the cross-sectional view is elliptical or teardrop-shaped.

[0010] In one example of this disclosure, the workpieces stacked in the stacking step include a second pilot hole that is to be tapped. The second pilot hole is stacked such that its depth direction is parallel to the stacking direction. The stacking is performed such that the cross-section in the direction perpendicular to the stacking direction is circular.

[0011] In one example of this disclosure, in the step of lamination, if the major axis of the first pilot hole is greater than or equal to a predetermined value, the first pilot hole is laminated such that the line with an angle θ of less than 45 degrees is longer than the line with an angle θ of 45 degrees or more. If the major axis of the first pilot hole is less than the predetermined value, the first pilot hole is laminated such that the cross-section in the direction perpendicular to the depth direction of the first pilot hole is circular.

[0012] In one example of this disclosure, the first pilot hole has a tap insertion opening, and the diameter of the insertion opening decreases as it moves away from the tap insertion side.

[0013] In one example of this disclosure, the additional processing method further comprises the steps of drilling the first pilot hole and tapping the first pilot hole that has been drilled.

[0014] Another example of the present disclosure provides an additive processing apparatus. The additive processing apparatus comprises a recoater for spreading metal powder material in a processing area of ​​a workpiece; a lifting mechanism configured to raise and lower the floor surface of the processing area; a plate configured to be detachably attached to the floor surface; an irradiation mechanism capable of performing stacking of the workpiece by irradiating the metal powder material spread in the processing area with laser light; and a control unit capable of stacking a workpiece of a predetermined shape in the processing area by repeatedly supplying the metal powder material to the processing area with the recoater, lowering the floor surface with the lifting mechanism, and irradiating with laser light with the irradiation mechanism. The workpiece of a predetermined shape includes a first pilot hole to be tapped. The control unit processes the first pilot hole in a stacking manner such that the depth direction of the first pilot hole is inclined with respect to the stacking direction of the workpiece, and in a cross-sectional view of the first pilot hole in a direction perpendicular to the depth direction, if the angle θ is the angle at which the tangent line of the upper half of the first pilot hole is inclined with respect to the stacking direction, the control unit processes the first pilot hole in a stacking manner such that the line where the angle θ is less than a predetermined angle is longer than the line where the angle θ is equal to or greater than the predetermined angle.

[0015] In other examples of this disclosure, a program for additive machining of a workpiece is provided. The additive machining program causes a computer to perform the following steps: lowering the floor of the workpiece machining area; after lowering the floor of the machining area, spreading metal powder material in the machining area; irradiating the metal powder material spread in the machining area with laser light; and repeating the lowering step, the spreading step, and the irradiating step to stack a workpiece of a predetermined shape in the machining area. The workpiece of the predetermined shape includes a first pre-drilled hole that is to be tapped. The above-described step of lamination includes lamination of the first pilot hole such that the depth direction of the first pilot hole is inclined with respect to the lamination direction of the workpiece, and, in a cross-sectional view of the first pilot hole in a direction perpendicular to the depth direction, if the angle θ is the angle at which the tangent line of the upper half of the first pilot hole is inclined with respect to the lamination direction, the 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.

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

[0017] [Figure 1] This figure shows an example of the configuration of an additive processing device. [Figure 2] This diagram shows the SLM (Steel Lump Processing) method of lamination in chronological order. [Figure 3] This diagram shows an example of a workpiece formed by additive manufacturing, viewed from the negative side in the Y-axis direction. [Figure 4] This diagram shows an example of a workpiece fabricated by additive manufacturing, viewed from the negative side in the Z-axis direction. [Figure 5] This figure shows the outer shape of the pilot hole according to the comparative example and the outer shape of the pilot hole according to the embodiment, viewed from the depth direction. [Figure 6]It is a view showing the cross-section of the blind hole along the VI-VI line shown in FIG. 3 from the positive side in the Z-axis direction. [Figure 7] It is a view showing the cross-section of the blind hole along the VII-VII shown in FIG. 3 from the negative side in the Y-axis direction. [Figure 8] It is a view showing the stacking process of the blind hole in chronological order from the negative side in the Y-axis direction. [Figure 9] It is a view showing the stacking process of the blind hole in chronological order from the negative side in the Z-axis direction. [Figure 10] It is a view showing an example of the drive mechanism of the additional processing device. [Figure 11] It is a view showing an example of the hardware configuration of the control unit. [Figure 12] It is a flowchart showing the flow of the stacking process by the additional processing device. [Figure 13] It is a flowchart showing the flow of the tapping process in the subsequent process.

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. In addition, each embodiment and each modification described below may be selectively combined as appropriate.

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

[0020] For the sake of convenience of explanation, hereinafter, the vertical direction will also be 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] Furthermore, 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 the additive processing device 100 is viewed from the front. Also, the rightward direction when the additive processing device 100 is viewed from the front is also referred to as the positive X-axis direction, and the leftward direction when the additive processing device 100 is viewed from the front is also referred to as the negative X-axis direction.

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

[0023] The additive processing device 100 is a processing machine capable of stacking workpieces using the SLM method. The additive processing device 100 irradiates a spread-out metal powder material with laser light, and stacks workpieces by locally melting and solidifying the metal powder material.

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

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

[0026] The storage area AR1 is partitioned, for example, by a lifting mechanism 130 and a wall surface 132. The wall surface 132 is configured to surround the upper surface of the lifting mechanism 130 when viewed from above.

[0027] The upper surface of the lifting mechanism 130 forms the floor surface of the storage area AR1. The upper surface of the lifting mechanism 130 is also configured to move up and down in the Z-axis direction. The lifting mechanism 130 is moved up and down by, for example, the motor 212Z (see Figure 10), which will be described later. The top of the storage area AR1 is open, and when the lifting mechanism 130 rises, the metal powder material PM is pushed out of the storage area AR1.

[0028] Furthermore, a processing area AR2 for the workpiece W is provided inside the additional processing device 100. The processing area AR2 is partitioned, 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 when viewed from above.

[0029] The upper surface of the lifting mechanism 140 forms the floor surface of the machining area AR2. The lifting mechanism 140 is also configured to move up and down in the Z-axis direction. The lifting mechanism 140 is moved up and down by, for example, the motor 222Z (see Figure 10), which will be described later. The upper part of the machining area AR2 is open.

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

[0031] The recoater 150 is configured to spread the metal powder material PM extruded from the storage area AR1 into the processing area AR2. The recoater 150 is composed of blades or rollers, 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 also 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 by, for example, 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 transported 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, referring 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 no metal powder material PM exists 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. Then, the additive processing apparatus 100 returns the recoater 150 to the 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 having a predetermined shape on the base plate 144 mounted on the floor surface of the processing area AR2.

[0042] <C. Summary> In the additive manufacturing process shown in Figure 2, tapping may be performed as a post-process. Tapping is a process that forms internal threads in a workpiece W. If the amount of material removed during tapping is large, the amount of chips will be large. In addition, the wear of cutting tools such as drills and taps will increase. Therefore, the additive manufacturing apparatus 100 according to the embodiment pre-forms pilot holes at the locations where tapping is to be performed. By pre-forming the pilot holes during additive manufacturing, the amount of material removed during the subsequent tapping process is reduced. As a result, wear of cutting tools can be suppressed.

[0043] The following describes an overview of the additive manufacturing method according to the embodiment, with reference to Figures 3 to 5. Figure 3 is a diagram showing an example of a workpiece W formed by additive manufacturing, viewed from the negative side in the Y-axis direction. Figure 4 is a diagram showing an example of a workpiece W formed by additive manufacturing, viewed from the negative side in the Z-axis direction.

[0044] In the examples shown in Figures 3 and 4, pilot holes PH1 and PH2, which are to be tapped, are formed in the workpiece W. Here, the additive processing apparatus 100 according to the embodiment causes the pilot hole PH1, whose depth direction is inclined with respect to the stacking direction, and the pilot hole PH2, whose depth direction is parallel to the stacking direction, to have different shapes during stacking. The pilot hole PH1 may be stacked so that its depth direction is perpendicular to the stacking direction, or it may be stacked so that the angle between the depth direction and the stacking direction is greater than 0 degrees and less than 90 degrees. In the example in Figure 3, the pilot hole PH1 is stacked so that its depth direction is perpendicular to the stacking direction.

[0045] Figure 5 shows the outer shape of the pilot hole PHX and the pilot hole PH1 according to the comparative example, viewed from the depth direction. The stacking direction LD shown in Figure 5 corresponds to the negative side of the Z axis. The boundary line L1 shown in Figure 5 indicates the line of the upper half of the pilot hole in a cross-sectional view in the direction perpendicular to the depth direction of the pilot hole. The boundary line L1 corresponds to the boundary between the irradiated and unirradiated parts of the laser beam LS. Furthermore, the tangent line TL shown in Figure 5 indicates the tangent to the boundary line L1. Hereafter, the angle at which the tangent line TL is inclined with respect to the stacking direction LD is defined as the inclination angle θ.

[0046] The hollow portion of the pilot hole PHX has a cylindrical shape. As the layering of pilot 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 that is supported by the metal powder material PM increases. Therefore, in areas with a large inclination angle θ, the solidified portion becomes more prone to collapse.

[0047] Therefore, the additive processing apparatus 100 according to the embodiment performs lamination processing such that the boundary line L1 with an inclination angle θ less than a predetermined angle is longer than the circular pilot hole PHX. In other words, the additive processing apparatus 100 performs lamination processing such that the boundary line L1 with an inclination angle θ less than a predetermined angle is longer than the boundary line L1 with an inclination angle θ equal to or greater than the predetermined angle. This makes collapse less likely to occur at the boundary line L1. The predetermined angle is, for example, 45 degrees.

[0048] As an example, the additive processing apparatus 100 performs lamination processing such that the shape of the pilot hole becomes elliptical or teardrop-shaped in a cross-sectional view perpendicular to the depth direction. In the example in Figure 5, a pilot hole PH1 with an elliptical cross-sectional shape is shown. The longer side of the ellipse is parallel to the lamination direction LD, and the shorter side of the ellipse is parallel to the horizontal direction.

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

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

[0051] <D. Cross-sectional shape of the pilot hole PH1> Next, referring to FIG. 6, the cross-sectional shape of the pilot hole PH1 shown in FIG. 3 will be described. FIG. 6 is a view showing the cross-section of the pilot hole 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 pilot hole PH1 is composed of an insertion port PH1A of a tap tool and a pilot hole portion PHIB continuous from the insertion port PH1A. The additive processing apparatus 100 performs lamination processing on the pilot hole 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 pilot hole PH1 is shaped with chamfering. As a result, the insertion port PH1A functions as a guide for the tap tool, and it becomes easier for the tap tool to be inserted into the pilot hole 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 pilot hole 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] Although FIG. 6 shows an example where the shape of the insertion port PH1A is a linear taper, the shape of the insertion port PHIA 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, referring 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 of a tap tool and a lower hole portion PH2B continuous from the insertion port PH2A. The additional processing device 100 laminates the lower hole PH2 so 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 chamfer. As a result, 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, referring to FIGS. 8 and FIG. 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. 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 device 100 repeatedly executes the lamination processing steps S1 to S3 described in FIG. 2 above. As a result, layers SL1 to SL3 are sequentially formed. At this time, when laminating layer SL3, the additive processing device 100 does not irradiate the laser light LS on the portion of the pilot hole PH1. As a result, the metal powder material PM remains as it is in the non-irradiated portion of the laser light LS, and the metal powder material PM melts and solidifies in the irradiated portion of the laser light LS.

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

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

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

[0064] <G. Driving mechanism of the additive processing device 100> Next, the drive mechanism in the additive processing device 100 will be described with reference to Figure 10. Figure 10 is a diagram showing an example of the drive mechanism of the additive processing device 100.

[0065] As shown in Figure 10, the additive processing apparatus 100 includes a control unit 50, the aforementioned lifting mechanisms 130 and 140, the aforementioned recoater 150, the aforementioned laser irradiation mechanism 160, and drive units 210, 220, 230, and 240.

[0066] The control unit 50 controls various devices within the additive processing apparatus 100. The device configuration of the control unit 50 is arbitrary. The control unit 50 may consist of a single control unit or multiple 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 lifting mechanism 130 described above. The drive unit 210 may consist of a single drive unit or multiple drive units. In the example in Figure 10, the drive unit 210 consists of a motor driver 211Z and a motor 212Z.

[0068] The motor driver 211Z sequentially receives input of the target position for the lifting mechanism 130 from the control unit 50 and outputs a current corresponding to the target position to the motor 212Z. As a result, the motor 212Z moves the lifting mechanism 130 to any position in the Z-axis direction. The motor 212Z may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0069] The drive unit 220 is a drive mechanism for driving the lifting mechanism 140 described above. The drive unit 220 may consist of a single drive unit or multiple drive units. In the example in Figure 10, the drive unit 220 consists of a motor driver 221Z and a motor 222Z.

[0070] The motor driver 221Z sequentially receives input of the target position for the lifting mechanism 140 from the control unit 50 and outputs a current corresponding to the target position to the motor 222Z. As a result, the motor 222Z moves the lifting mechanism 140 to any 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 recoater 150 described above. The drive unit 230 may consist of a single drive unit or multiple drive units. In the example in Figure 10, the drive unit 230 consists of a motor driver 231X and a motor 232X.

[0072] The motor driver 231X sequentially receives input of a target position for the recoater 150 from the control unit 50 and outputs a current corresponding to the target position to the motor 232X. As a result, the motor 232X moves the recoater 150 to any 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 rotating the galvanometer mirrors 162A and 162B within the laser irradiation mechanism 160. The drive unit 240 may consist of a single drive unit or multiple drive units. In the example shown in Figure 10, the drive unit 240 consists of motor drivers 241A and 241B and motors 242A and 242B.

[0074] The motor driver 241A sequentially receives an input of a target rotation angle or a target rotation speed of the galvanometer mirror 162A centered on the X-axis direction from the control unit 50, 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 turn 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 an input of a target rotation angle or a target rotation speed of the galvanometer mirror 162B centered on the Y-axis direction from the control unit 50, 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 turn 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, referring 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 comprised of, for example, at least one integrated circuit. The integrated circuit may consist of, 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 additive machining program 122. The additive machining program 122 is a program for realizing the various processes described herein. Based on receiving an execution command for the additive machining program 122, the control circuit 101 reads the additive machining program 122 from the ROM 102 into the RAM 103. The RAM 103 functions as working memory and temporarily stores various data necessary for the execution of the additive machining program 122.

[0081] The communication interface 104 is an interface for enabling communication with various devices. The additive processing device 100 communicates, for example, with various drive units (for example, the drive units 210, 220, 230, 240, etc.) for performing additive processing on a workpiece via the communication interface 104.

[0082] The auxiliary storage device 120 is, for example, a storage medium such as a hard disk or flash memory. The auxiliary storage device 120 stores the additive processing program 122 and three-dimensional data 124, etc. The additive processing program 122 is, for example, pre-generated from the three-dimensional data 124 of the workpiece W. The additive processing device 100 creates the workpiece W with the shape shown in the three-dimensional data 124 by executing the additive processing program 122.

[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), etc.

[0084] Also, the additional processing program 122 may be provided by being 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 part of the processing of the additional processing program 122.

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

[0086] The processing shown in FIG. 12 is realized, for example, when the control unit 50 of the additional processing device 100 executes the above-mentioned additional processing program 122. In other aspects, part or all of the processing 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 work W. "N" is a natural number. The initial value of "N" is "1".

[0088] In step S112, the control unit 50 raises the above-mentioned lifting mechanism 130. The lifting width of the lifting mechanism 130 is preset. Thereby, the metal powder material PM is extruded from the storage area AR1.

[0089] In step S114, the control unit 50 lowers the lifting mechanism 140. The lowering range of the lifting mechanism 140 is predetermined. This lowering range corresponds to the thickness of one layer of the workpiece W. As a result, a space where no metal powder material PM exists 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, to the negative side in the X-axis direction. At this time, the control unit 50 drives the recoater 150 so that, in a top view, the recoater 150 passes sequentially through the storage area AR1 and the processing area AR2. As a result, the metal powder material PM is supplied from the storage area AR1 to the processing area AR2. After that, the control unit 50 returns the recoater 150 to the predetermined waiting 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 metal powder material PM spread in the processing area AR2 with laser light LS. At this time, the control unit 50 performs the stacking process on the pilot hole PH1, whose depth direction is inclined with respect to the stacking direction of the workpiece, so that the cross-section becomes non-circular. On the other hand, the control unit 50 performs the stacking process on the pilot hole PH2, whose depth direction is parallel to the stacking direction of the workpiece, so that the cross-section becomes circular. The stacking method for pilot holes PH1 and PH2 is as described above, so it will not be repeated.

[0092] In step S120, the control unit 50 determines whether a predetermined termination condition has been met. For example, the termination condition is met when the variable "N" is greater than or equal to a predetermined value. If the control unit 50 determines that the predetermined termination condition has been met (YES in step S120), it terminates the process shown in Figure 12. Otherwise (NO in step S120), the control unit 50 switches control to step S122.

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

[0094] <J. Flow related to post-process> Next, referring to FIG. 13, the control flow of the post-process of the laminated processing 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 additive processing device 100. The tapping process in the post-process may be executed by the additive processing device 100 or may be executed by a machine tool different from the additive 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 additive processing device 100. Also, 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 additive processing device 100. At this time, the machine tool inserts the drill tool into the pilot hole PH in a state where the rotation axis of the drill tool and the depth direction of the pilot hole PH are overlapped. 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). Also, 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 additional 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 additional processing device 100 performed 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 diameter of the pilot hole PH1 is greater than or equal to a predetermined value, the additional processing device 100 shapes the pilot hole PH1 so that the cross section becomes non-circular. The major diameter 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 diameter of the pilot hole PH1 is greater than or equal to a predetermined value, the additional 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 is longer than the boundary line L1 where it is 45 degrees or more. As an example, the additional processing device 100 shapes the pilot hole PH1 having an elliptical or teardrop-shaped cross section.

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

[0103] The shorter the diameter of the pilot hole PH1, the greater the load on the tool in the subsequent process. However, in this example, when the diameter of the pilot hole PH1 is short, a pilot hole PH1 with a circular cross-section is formed. This reduces the load on the tool in the subsequent process, thereby suppressing tool wear and tool breakage.

[0104] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0105] 50 Control unit, 100 Add-on processing device, 101 Control circuit, 102 ROM, 103 RAM, 104 Communication interface, 109 Internal bus, 120 Auxiliary storage device, 122 Add-on 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 stacking direction, LS laser beam, PH pilot hole, PH1 pilot hole, PH1A insertion port, PH1B pilot hole section, PH2 pilot hole, PH2A insertion port, PH2B pilot hole section, PHX pilot hole, PM metal powder material, SL1~SL14 layers, TL tangent, W workpiece, ΔR1A diameter, ΔR1B diameter, ΔR2A diameter, ΔR2B diameter, θ inclination angle.

Claims

1. A method for additional machining of a workpiece, A step that lowers the floor surface of the workpiece processing area, The steps include lowering the floor of the processing area, then spreading metal powder material over the processing area, The steps include irradiating the metal powder material spread in the processing area with laser light, The process includes a step of stacking workpieces of a predetermined shape in the processing area by repeating the steps of lowering, laying, and irradiating, The workpiece of the predetermined shape includes a first pilot hole that is to be tapped, The first pilot hole is, The first pilot hole is stacked in such a way that its depth direction is inclined with respect to the stacking direction of the workpiece. An additive processing method in which, in a cross-sectional view of the first pilot hole in a direction perpendicular to the depth direction, the angle at which the tangent line of the upper half of the first pilot hole is inclined with respect to the stacking direction is defined as angle θ, and the stacking process is performed such that the line where the angle θ is less than a predetermined angle is longer than the line where the angle θ is equal to or greater than the predetermined angle.

2. The additional processing method according to claim 1, wherein the predetermined angle is 45 degrees.

3. The additional processing method according to claim 1 or 2, wherein the shape of the first pilot hole in the cross-sectional view is elliptical or teardrop-shaped.

4. The workpieces stacked in the aforementioned stacking step include a second pilot hole that is to be tapped, The second pilot hole is, The second pilot hole is laminated so that its depth direction is parallel to the lamination direction. The additive processing method according to claim 1 or 2, wherein the lamination process is performed such that the cross-section in the direction perpendicular to the lamination direction is circular.

5. In the aforementioned lamination process, If the major diameter of the first pilot hole is greater than or equal to a predetermined value, the first pilot hole is laminated such that the line with an angle θ of less than 45 degrees is longer than the line with an angle θ of 45 degrees or more. The additional processing method according to claim 1 or 2, wherein if the major diameter of the first pilot hole is less than the predetermined value, the first pilot hole is laminated so that the cross-section in the direction perpendicular to the depth direction of the first pilot hole is circular.

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

7. The aforementioned additional processing method further includes: The steps include drilling the first pilot hole, The additional machining method according to claim 1 or 2, further comprising the step of tapping the first pilot hole that has been drilled.

8. A recoater for spreading metal powder material in the workpiece processing area, A lifting mechanism configured to allow the floor surface of the aforementioned processing area to be raised and lowered, A plate configured to be detachably attached to the floor surface, An irradiation mechanism capable of performing stacking processing of the workpiece by irradiating a laser beam onto a metal powder material spread in the processing area, The system includes a control unit that can perform stacking processing of a workpiece of a predetermined shape in the processing area by repeatedly supplying metal powder material to the processing area using the recoater, lowering the floor surface using the lifting mechanism, and irradiating with laser light using the irradiation mechanism, The workpiece of the predetermined shape includes a first pilot hole that is to be tapped, The control unit, The first pilot hole is processed in such a way that its depth direction is inclined with respect to the stacking direction of the workpiece, An additive processing apparatus that performs a lamination process on the first pilot hole such that, in a cross-sectional view of the first pilot hole in a direction perpendicular to the depth direction, the angle θ is the angle at which the tangent line of the upper half of the first pilot hole is inclined with respect to the lamination direction, and the 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.

9. An additional machining program for a workpiece, The aforementioned additional processing program is programmed into a computer. A step that lowers the floor surface of the workpiece processing area, The steps include lowering the floor of the processing area, then spreading metal powder material over the processing area, The steps include irradiating the metal powder material spread in the processing area with laser light, By repeating the steps of lowering, laying, and irradiating, the process of stacking workpieces of a predetermined shape in the processing area is performed. The workpiece of the predetermined shape includes a first pilot hole that is to be tapped, The aforementioned step of lamination processing is, The first pilot hole is processed in such a way that its depth direction is inclined with respect to the stacking direction of the workpiece, An additive machining program comprising the step of laminating the first pilot hole such that, in a cross-sectional view of the first pilot hole in a direction perpendicular to the depth direction, the angle θ is the angle at which the tangent line of the upper half of the first pilot hole is inclined with respect to the lamination direction, and the 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.

Images