ADDITIONAL PROCESSING APPARATUS, ADDITIONAL PROCESSING METHOD, AND ADDITIONAL PROCESSING PROGRAM

Abstract

To provide a technology for dealing with thermal expansion during additional processing of a workpiece in a manner different from the conventional method. [Solution] The additive machining device includes a laser head that performs additive machining of a workpiece, a first support section that supports one side of the workpiece in a predetermined axial direction and supports the workpiece rotatably about the predetermined axis, a second support section that supports the other side of the workpiece in the predetermined axial direction and supports the workpiece rotatably about the predetermined axis, a drive section that moves the second support section along the predetermined axial direction, a first detection section that detects a physical quantity that is correlated with a torque applied to the drive section, and a control section. The control section executes a process of controlling the drive section so that the physical quantity detected by the first detection section approaches a predetermined target value during additive machining of the workpiece or during cooling of the workpiece.

Description

[Technical field]

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

[0002] JP 2023-125537 A (Patent Document 1) discloses a processing machine capable of maintaining high processing accuracy of a workpiece in additional processing of the workpiece using a directed energy deposition method. The processing machine includes an additional processing head that supplies powder material to the workpiece and irradiates it with laser light, and a first holding unit and a second holding unit for rotatably holding the workpiece. The first holding unit and the second holding unit are provided opposite each other in the direction of the rotation axis of the workpiece and are configured to hold the workpiece from both sides.

[0003] When the laser light is irradiated onto the workpiece, the workpiece thermally expands (see paragraph

[0005] ). Therefore, the processing machine moves the first holding part and the second holding part relatively away from each other when additional processing is performed on the workpiece. This prevents the surface of the workpiece from being distorted between the first holding part and the second holding part, improving the accuracy of additional processing of the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-125537 A Summary of the Invention [Problem to be solved by the invention]

[0005] The processing machine disclosed in Patent Document 1 detects the temperature of the workpiece during additional processing of the workpiece, and calculates the amount of thermal expansion of the workpiece based on the temperature. The processing machine then moves the first holding unit and the second holding unit away from each other by a distance corresponding to the calculated amount of thermal expansion. In this way, it is possible to suppress distortion of the workpiece surface due to thermal expansion during additive manufacturing. However, when the shape of the workpiece is not a simple cylindrical shape or a shape similar to it, but has a complex shape, it may take a long time to calculate the amount of thermal expansion of the workpiece.

[0006] In view of the above, there is a need for a technology that can deal with thermal expansion during additional processing of a workpiece in a manner different from that used conventionally. [Means for solving the problem]

[0007] In one example of the present disclosure, an additive processing device for performing additive processing of a workpiece is provided. The additive processing device includes a laser head capable of performing additive processing of the workpiece by supplying a powder material to the workpiece and irradiating the workpiece with a laser beam, a first support unit for supporting one side of the workpiece in a direction of a predetermined axis and supporting the workpiece rotatably about the predetermined axis, a second support unit for supporting the other side of the workpiece in the direction of the predetermined axis and supporting the workpiece rotatably about the predetermined axis, a drive unit for moving the second support unit along the direction of the predetermined axis, a first detection unit for detecting a physical quantity correlated with a torque applied to the drive unit, and a control unit for controlling the additive processing device. The control unit executes a process of controlling the drive unit so that the physical quantity detected by the first detection unit approaches a predetermined target value during additive processing of the workpiece or cooling of the workpiece.

[0008] In one example of the present disclosure, the additional processing device further includes a second detection unit for detecting a position of the second support unit in the direction of the predetermined axis. The control unit further executes, while executing a process for controlling the drive unit, a process for monitoring whether the position is within a preset range, and a process for implementing a predetermined abnormality handling process when the position is out of the preset range.

[0009] In one example of the present disclosure, the abnormality handling process includes a process of switching from a process of controlling the drive unit so that the physical quantity approaches the predetermined target value to a process of controlling the drive unit so that the position detected by the second detection unit approaches a target position.

[0010] In one example of the present disclosure, the abnormality handling process includes outputting a warning indicating that the position is outside the preset range.

[0011] In one example of the present disclosure, the first support is a first work spindle having a chuck mechanism for gripping one side of the workpiece, and the second support is a second work spindle having a chuck mechanism for gripping the other side of the workpiece.

[0012] In one example of the present disclosure, the first support is a work spindle having a chuck mechanism for gripping one side of the work, and the second support is a tailstock having a tailstock mechanism for tailstocking the other side of the work.

[0013] In another example of the present disclosure, an additional processing device for performing additional processing of a workpiece is provided. The additional processing device includes a laser head capable of performing additional processing of the workpiece by supplying a powder material to the workpiece and irradiating the workpiece with a laser beam, a first support unit for gripping one side of the workpiece in a direction of a predetermined axis and rotatably holding the workpiece about the predetermined axis, a second support unit for gripping the other side of the workpiece in the direction of the predetermined axis and rotatably holding the workpiece about the predetermined axis, a drive unit for moving the second support unit along the direction of the predetermined axis, and a control unit for controlling the additional processing device. The control unit executes a process for disabling the control process of the drive unit during additional processing of the workpiece or during cooling of the workpiece.

[0014] In another example of the present disclosure, a method for additionally processing a workpiece using an additional processing device is provided. The additional processing device includes a laser head capable of performing additional processing on the workpiece by supplying a powder material to the workpiece and irradiating the workpiece with a laser beam, a first support part for supporting one side of the workpiece in a direction of a predetermined axis and supporting the workpiece rotatably around the predetermined axis, and a second support part for supporting the other side of the workpiece in the direction of the predetermined axis and supporting the workpiece rotatably around the predetermined axis. a drive unit for moving the second support unit along the direction of the predetermined axis, and a first detection unit for detecting a physical quantity correlated with a torque applied to the drive unit. The additional machining method includes a step of controlling the drive unit so that the physical quantity detected by the first detection unit approaches a predetermined target value during additional machining of the workpiece or during cooling of the workpiece.

[0015] In another example of the present disclosure, a program for additive machining of a workpiece by an additive machining apparatus is provided. The additive machining apparatus includes a laser head capable of performing additive machining of the workpiece by supplying a powder material to the workpiece and irradiating the workpiece with a laser beam, a first support unit for supporting one side of the workpiece in a direction of a predetermined axis and supporting the workpiece rotatably about the predetermined axis, a second support unit for supporting the other side of the workpiece in the direction of the predetermined axis and supporting the workpiece rotatably about the predetermined axis, a drive unit for moving the second support unit along the direction of the predetermined axis, and a first detection unit for detecting a physical quantity correlated with a torque applied to the drive unit. The additive machining program causes the additive machining apparatus to execute a process of controlling the drive unit so that the physical quantity detected by the first detection unit approaches a predetermined target value during additive machining of the workpiece or cooling of the workpiece.

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

[0017] [Figure 1] FIG. 2 is a diagram showing an example of the appearance of an additional processing device. [Diagram 2] FIG. 2 is a diagram showing an example of a device configuration of an additional processing device. [Diagram 3] FIG. 2 shows a cross section of a laser head during additional processing. [Figure 4] FIG. 13 is a diagram illustrating a control mode of the second work spindle during additional machining. [Diagram 5] FIG. 13 is a diagram illustrating a control mode of the second work spindle after additional machining is completed. [Figure 6] FIG. 4 is a diagram illustrating a schematic diagram of a position monitoring function of a second work spindle. [Figure 7] FIG. 13 illustrates an example of a warning screen. [Figure 8] FIG. 2 is a diagram showing an example of a drive mechanism of an additional processing device. [Figure 9] This is a diagram showing an example of the hardware configuration of the control unit. [Figure 10] This is a flowchart showing the flow of the additional processing. [Figure 11] This is a diagram for explaining a modified example of the control method of the second workpiece spindle.

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 modified example described below may be selectively combined as appropriate.

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

[0020] The additional processing device 100 is a processing machine capable of performing additional processing (AM (Additive manufacturing) processing) on a workpiece. The additional processing device 100 performs additional processing by supplying a powder material to the workpiece and irradiating the workpiece with a laser beam.

[0021] Note that the additional processing device 100 may be a processing machine capable of not only additional processing of a workpiece but also subtractive processing (SM (Subtractive manufacturing)) of the workpiece. Examples of the subtractive processing function include a milling function and a turning function.

[0022] The additional processing device 100 includes, for example, a cover body 130 and an operation panel 200.

[0023] The cover body 130 is a mechanism for protecting the components provided inside the additional processing device 100. A door DR is provided on the cover body 130. The door DR is, for example, a slide-type door. The door DR may be configured to be openable and closable by a drive source such as a motor, or may be configured to be openable and closable manually.

[0024] The operation panel 200 is a general-purpose computer and has a display for displaying various pieces of information related to processing. The display is, for example, a liquid crystal display, an organic EL (Electro Luminescence) display, or other display device. Further, the display is provided with a touch panel and accepts various operations on the additional processing device 100 by touch operations.

[0025] <B. Device Configuration of Additional Processing Device 100> Next, with reference to FIG. 2, the device configuration of the additional processing device 100 will be described. FIG. 2 is a diagram showing an example of the device configuration of the additional processing device 100. In FIG. 2, as an example of the additional processing device 100, an AM / SM hybrid processing machine capable of both additional processing and removal processing of a workpiece is shown.

[0026] As described above, the additional processing device 100 includes a cover body 130. The cover body 130 forms the appearance of the additional processing device 100 and partitions and forms a processing area AR for performing additional processing on the workpiece W.

[0027] Further, the additional processing device 100 includes a bed 11, a tool rest 16, a first support portion 21, a second support portion 24, a tool spindle 30, and a laser head 140.

[0028] For ease of explanation, the rotation axis direction of the first support part 21 and the second support part 24 is also referred to as the "Z axis direction". In the example of FIG. 2, the Z axis direction is a direction parallel to the rotation axes AX1 to AX3. One side in the Z axis direction is also referred to as the "Z axis direction positive side", and the other side in the Z axis direction is also referred to as the "Z axis direction negative side". In the example of FIG. 2, the right side when viewing the processing area AR from the door DR is the "Z axis direction positive side". In the example of FIG. 2, the left side when viewing the processing area AR from the door DR is the "Z axis direction negative side".

[0029] Furthermore, one direction on the horizontal plane perpendicular to the Z-axis direction is also referred to as the "Y-axis direction." One side in the Y-axis direction is also referred to as the "Y-axis positive side," and the other side in the Y-axis direction is also referred to as the "Y-axis negative side."

[0030] Furthermore, the direction perpendicular to both the Y-axis direction and the Z-axis direction is also referred to as the "X-axis direction." One side of the X-axis direction is also referred to as the "X-axis positive side," and the other side of the X-axis direction is also referred to as the "X-axis negative side." In the example of Figure 2, the X-axis negative side corresponds to the direction of gravity.

[0031] The bed 11 is a base member for supporting various devices in the additive machining apparatus 100. In the example of Fig. 2, the bed 11 supports the tool rest 16, the first support portion 21, the second support portion 24, the tool spindle 30, and the laser head 140. The bed 11 is installed on the floor of a factory or the like. The bed 11 is made of metal such as cast iron.

[0032] The tool rest 16 has a turret 18. The turret 18 is configured to be rotatable about a rotation axis AX1. The turret 18 holds a plurality of tools at intervals in the circumferential direction about the rotation axis AX1. The tool rest 16 is also configured to be movable in the X-axis direction and the Y-axis direction by various driving mechanisms such as a motor. The tool rest 16 performs turning by bringing a fixed tool held by the turret 18 into contact with the workpiece W that is rotated by a first support portion 21.

[0033] The first support part 21 is configured to support one side of the workpiece W in the direction of the rotation axis AX2. The rotation axis AX2 is a direction along the axial direction of the first support part 21. The first support part 21 is configured to be rotatable about the rotation axis AX2 along the axial direction. The first support part 21 is rotationally driven, for example, by 212C (see FIG. 8) described later.

[0034] Any mechanism may be adopted as the support mechanism for the workpiece W by the first support portion 21. A first workpiece spindle 22 is shown in FIG. 2 as an example of the first support portion 21. The first workpiece spindle 22 is provided with a chuck mechanism 23 for gripping one side of the workpiece W. The chuck mechanism 23 is a mechanism for fixing the workpiece W to the first workpiece spindle 22.

[0035] The second support part 24 is disposed opposite to the first support part 21 in the axial direction of the rotation axis AX2 or the rotation axis AX3. The rotation axis AX3 is in the axial direction of the first support part 21 and is coaxial with the rotation axis AX2. In other words, the second support part 24 is configured to support the other side of the workpiece W in the direction of the rotation axis AX3.

[0036] The rotation axis AX3 is a direction along the axial direction of the second support part 24. The second support part 24 is configured to be rotatable about the rotation axis AX3 along the axial direction. The second support part 24 is configured to rotate, for example, following the rotation of the first support part 21.

[0037] Any mechanism may be adopted as the support mechanism for the workpiece W by the second support portion 24. In Fig. 2, a second workpiece spindle 25 is shown as an example of the second support portion 24. The second workpiece spindle 25 is provided with a chuck mechanism 26 for gripping the other side of the workpiece W. The chuck mechanism 26 is a mechanism for fixing the workpiece W to the second workpiece spindle 25.

[0038] As another example, the second support portion 24 may be a tailstock (not shown). The tailstock is provided with a tailstock mechanism for supporting the other side of the workpiece W. In this case, the tailstock is provided with a center pin (not shown) instead of the chuck mechanism 26. The center pin has a pin shape that extends in the direction of the rotation axis AX3. As a result, the center pin tailstocks the end face of the workpiece W from the side opposite to the first support portion 21.

[0039] In the following, the description will be given on the assumption that the first support part 21 is the first work spindle 22, but the first support part 21 is not limited to the first work spindle 22. In the following, the description will be given on the assumption that the second support part 24 is the second work spindle 25, but the second support part 24 is not limited to the second work spindle 25.

[0040] The tool spindle 30 is provided, for example, at a position higher than the first work spindle 22 and the second work spindle 25. The tool spindle 30 is configured to allow a tool and a laser head 140 to be detachably attached thereto. Fig. 2 shows an example in which the laser head 140 is attached to the tool spindle 30.

[0041] The laser head 140 is attached to and detached from the tool spindle 30 by, for example, an automatic tool changer (ATC). The additional machining device 100 attaches the laser head 140 to the tool spindle 30 when performing additional machining of the workpiece W. On the other hand, the additional machining device 100 attaches a tool to the tool spindle 30 when performing removal machining of the workpiece W.

[0042] One example of the removal process is milling, in which a rotating tool is brought into contact with the workpiece W fixed to the first workpiece spindle 22. Another example of the removal process is turning, in which a tool is pressed against the workpiece W rotating about the rotation axis AX2.

[0043] The laser head 140 performs additive manufacturing by the DED (Direct Energy Deposition) method while being mounted on the tool spindle 30. As a mechanism for realizing additive manufacturing, the laser head 140 has a head body 142 and a laser nozzle 146.

[0044] Powder material is supplied to the head body 142 via a cable (not shown). The supplied powder material may be metal powder, resin powder, or other types of powder that melt upon irradiation with laser light.

[0045] The laser nozzle 146 irradiates the workpiece W with laser light and defines the laser light irradiation region on the workpiece W. The powder material supplied to the laser head 140 is discharged toward the workpiece W through the laser nozzle 146.

[0046] <C. Additive Manufacturing> Next, with reference to FIG. 3, the additive manufacturing by the laser head 140 will be described in more detail. FIG. 3 is a diagram showing a cross section of the laser head 140 during additive manufacturing.

[0047] The additive manufacturing apparatus 100 can realize various additive manufacturing processes by controlling the laser head 140. Examples of the types of additive manufacturing include layer manufacturing and coating. Layer manufacturing is a process of stacking layers SL on the workpiece W. Coating is a process of covering part or all of the surface of the workpiece W with the layer SL.

[0048] The additive manufacturing apparatus 100 according to the embodiment is configured to enable high-speed additive manufacturing. Examples of high-speed additive manufacturing techniques include, for example, EHLA (Extreme High-speed Laser Application).

[0049] More specifically, while moving in the Z-axis direction, the laser head 140 irradiates the rotating workpiece W with the laser beam LS. As a result, the irradiated portion of the laser beam LS melts, and a molten pool MP is formed on the workpiece W.

[0050] Also, in parallel with the irradiation of the laser beam LS, the laser head 140 supplies the powder material PM to the workpiece W. The supplied powder material PM melts before reaching the surface of the workpiece W by the laser beam LS. As a result, the molten powder material PM is introduced into the molten pool MP. When the molten pool MP hardens on the workpiece W, it becomes a layer SL.

[0051] Note that the additive processing by the additive processing device 100 does not necessarily have to be high-speed additive processing. As an example, the additive processing device 100 may realize the additive processing of the workpiece W by additive processing that rotates the first workpiece spindle 22 at a low speed. In this case, the additive processing device 100 performs the additive processing with the focus F of the laser beam LS positioned on the surface of the workpiece W.

[0052] <D. Control Method of the Second Workpiece Spindle 25 During Additive Processing> Next, with reference to FIG. 4, the control method of the second workpiece spindle 25 during additive processing will be described. FIG. 4 is a diagram schematically showing the control mode of the second workpiece spindle 25 during additive processing.

[0053] As described above, the second workpiece spindle 25 is configured to be movable along its axial direction (i.e., the Z-axis direction). The movement is driven by a motor 222Z (drive unit). The drive of the motor 222Z is controlled by the control unit 50 of the additive processing device 100.

[0054] The additional processing device 100 also includes a sensor 322 (first detection unit). The sensor 322 is a sensor for detecting a physical quantity correlated with the torque applied to the motor 222Z. The physical quantity is, for example, the output current to the motor 222Z. In this case, the sensor 322 is a current sensor, and detects the magnitude (load current value) of the output current to the motor 222Z. The current value detected by the sensor 322 is output to the control unit 50.

[0055] Another example of the physical quantity is the load applied to the drive shaft of the motor 222Z. In this case, the sensor 322 is a torque sensor provided on the drive shaft of the motor 222Z, and directly detects the load (torque) applied to the drive shaft.

[0056] For ease of explanation, hereinafter, a physical quantity that is correlated with the torque applied to the motor 222Z will also be simply referred to as "torque".

[0057] In step S1, the control unit 50 causes the first work spindle 22 and the second work spindle 25 to hold the workpiece W. Next, the control unit 50 controls the first work spindle 22 to rotate the workpiece W. As a result, the workpiece W rotates about the Z-axis direction. Thereafter, the control unit 50 controls the operation of the laser head 140 to perform additional processing on the workpiece W held by the first work spindle 22 and the second work spindle 25. As a result, the laser head 140 supplies the powder material PM to the rotating workpiece W and irradiates the laser light LS.

[0058] When the workpiece W is irradiated with the laser beam LS during additional processing of the workpiece W, the workpiece W thermally expands. At this time, if both the first workpiece spindle 22 and the second workpiece spindle 25 are fixed to the additional processing device 100, the surface of the workpiece W is distorted so as to protrude radially outward from the rotation axis. However, in the additional processing device 100 according to the embodiment, the second workpiece spindle 25 is configured to be movable along its axial direction (i.e., the Z-axis direction). Therefore, the second workpiece spindle 25 moves according to the extension of the workpiece W on the positive side in the Z-axis direction. In step S2, the workpiece W has extended on the positive side in the Z-axis direction by a length ΔL1 due to thermal expansion compared to step S1.

[0059] The control unit 50 according to the embodiment controls the motor 222Z during additional machining of the workpiece so that the torque detected by the sensor 322 approaches a predetermined target value. In other words, the control unit 50 controls the motor 222Z so that the torque detected by the sensor 322 becomes constant. The target value is set, for example, to a predetermined percentage (e.g., 90 percent) of the maximum allowable torque.

[0060] Hereinafter, the control mode for keeping the torque of the motor 222Z constant is also referred to as “torque feedback control.” The torque feedback control may be realized by PI (Proportional-Integral) control, PD (Proportional-Differential) control, or PID (Proportional-Integral-Differential) control.

[0061] More specifically, when the torque detected by the sensor 322 is greater than a predetermined target value, the control unit 50 controls the motor 222Z to drive the second work spindle 25 to the positive side in the Z axis direction. In the example of Fig. 4, the control unit 50 moves the second work spindle 25, which was at position "ZR1" in step S1, to the positive side in the Z axis direction by a length of "ΔZ1" in step S2. As a result, the second work spindle 25 is driven to position "ZR2".

[0062] Thus, it is possible to suppress the surface of the workpiece W from being distorted as the workpiece W thermally expands. As a result, the additive processing apparatus 100 can laminate the powder material PM at an intended position on the surface of the workpiece W, and can perform high-precision additive processing on the workpiece W. Further, the additive processing apparatus 100 can cope with the thermal expansion of the workpiece W without simulating the amount of thermal expansion of the workpiece.

[0063] In the above description, an example in which the second workpiece spindle 25 is driven in the Z-axis direction in response to the thermal expansion of the workpiece W has been described. However, the first workpiece spindle 22 may be driven in the Z-axis direction in response to the thermal expansion of the workpiece W. Alternatively, both the first workpiece spindle 22 and the second workpiece spindle 25 may be driven in the Z-axis direction in response to the thermal expansion of the workpiece W.

[0064] <E. Control Method of the Second Workpiece Spindle 25 During Cooling of the Workpiece> Next, with reference to FIG. 5, a control method of the second workpiece spindle 25 during cooling of the workpiece will be described. FIG. 5 is a diagram schematically showing a control mode of the second workpiece spindle 25 during cooling of the workpiece.

[0065] In step S3, it is assumed that the additive processing of the workpiece W is completed. Accordingly, the control unit 50 controls the laser head 140 to stop the supply of the powder material PM and the irradiation of the laser beam LS. Thereafter, as the temperature of the workpiece W decreases, the workpiece W thermally contracts. Since the first workpiece spindle 22 is fixed, the workpiece W contracts in the negative Z-axis direction. In step S4, the workpiece W contracts by an amount ΔL2 in the negative Z-axis direction due to thermal contraction as compared with step S3. At this time, if the position of the second workpiece spindle 25 is fixed, residual stress may be generated in the workpiece W.

[0066] Therefore, even after the additional processing of the workpiece, the control unit 50 continues the torque feedback control. More specifically, when the torque detected by the sensor 322 is smaller than a predetermined target value, the control unit 50 controls the motor 222Z so as to drive the second workpiece spindle 25 in the negative Z-axis direction. In the example of FIG. 5, the control unit 50 moves the second workpiece spindle 25, which was at the position "ZR3" in step S3, in the negative Z-axis direction by the length of "ΔZ2" in step S4. As a result, the second workpiece spindle 25 is driven to the position "ZR4".

[0067] Thereby, it is possible to suppress the residual stress from remaining in the workpiece W after the additional processing of the workpiece W. As a result, the quality of the workpiece W after the additional processing is improved.

[0068] In the above description, an example in which the second workpiece spindle 25 is driven in the Z-axis direction according to the thermal contraction of the workpiece W has been described. However, the first workpiece spindle 22 may be driven in the Z-axis direction according to the thermal contraction of the workpiece W. Alternatively, both the first workpiece spindle 22 and the second workpiece spindle 25 may be driven in the Z-axis direction according to the thermal contraction of the workpiece W.

[0069] <F. Position monitoring function> As described above, when performing the additional processing of the workpiece W, the control unit 50 executes the above-described torque feedback control. Thereby, the position of the second workpiece spindle 25 moves according to the thermal expansion and thermal contraction of the workpiece W. At this time, preferably, the control unit 50 monitors the position of the second workpiece spindle 25 so that the position of the second workpiece spindle 25 does not deviate from the normal range.

[0070] Hereinafter, with reference to FIG. 6, the position monitoring function of the second workpiece spindle 25 will be described. FIG. 6 is a diagram schematically showing the position monitoring function of the second workpiece spindle 25.

[0071] The additional machining device 100 includes a position sensor 324 for detecting the position in the movement direction (i.e., the Z-axis direction) of the second workpiece spindle 25. Any type of position sensor 324 may be used. As an example, the position sensor 324 is a linear encoder. The position detected by the position sensor 324 is output to the control unit 50.

[0072] Before the start of additional machining in step S11, the control unit 50 causes the first workpiece spindle 22 and the second workpiece spindle 25 to hold the workpiece W. At this time, the control unit 50 acquires the position "ZR1" of the second workpiece spindle 25 from the position sensor 324, and sets a normal range ΔR with the position "ZR1" as the reference position. The lower limit of the normal range ΔR is, for example, a value obtained by subtracting a predetermined value (for example, 5 mm) from the reference position "ZR1". The upper limit of the normal range ΔR is, for example, a value obtained by adding a predetermined value (for example, 5 mm) to the reference position "ZR1".

[0073] In step S12, the control unit 50 starts additional machining based on the torque feedback control described above. While the control unit 50 is executing the torque feedback control, the control unit 50 periodically acquires the current position of the second work spindle 25 and monitors whether the acquired current position is within a preset normal range ΔR. Then, when the current position of the second work spindle 25 is out of the normal range ΔR, the control unit 50 executes a predetermined abnormality handling process.

[0074] As an example of the abnormality handling process, the control unit 50 executes a process of stopping the additional processing. In this case, the control unit 50 controls the laser head 140 to stop the supply of the powder material PM and the irradiation of the laser light LS.

[0075] As another example of the abnormality handling process, the control unit 50 stops the drive process of the motor 222Z based on the torque feedback control described above, and executes a process of controlling the motor 222Z so as to maintain the position of the second work spindle 25 at the current position. That is, the control unit 50 switches from torque feedback control that keeps the torque applied to the second work spindle 25 constant to position feedback control that keeps the position of the second work spindle 25 constant. This makes it possible to prevent the position of the second work spindle 25 from significantly deviating from the normal range ΔR.

[0076] More specifically, when the position detected by the position sensor 324 is greater than a predetermined target position, the control unit 50 controls the motor 222Z to drive the second work spindle 25 to the negative side in the Z axis direction. On the other hand, when the position detected by the position sensor 324 is less than the predetermined target position, the control unit 50 controls the motor 222Z to drive the second work spindle 25 to the positive side in the Z axis direction.

[0077] The above-mentioned predetermined target position is appropriately switched depending on whether the position of the second work spindle 25 exceeds the upper limit of the normal range ΔR or falls below the lower limit of the normal range ΔR. More specifically, when the position of the second work spindle 25 exceeds the upper limit of the normal range ΔR, the control unit 50 sets the above-mentioned predetermined target position to the upper limit of the normal range ΔR. On the other hand, when the position falls below the lower limit of the normal range ΔR, the control unit 50 sets the above-mentioned predetermined target position to the lower limit of the normal range ΔR.

[0078] As yet another example of the abnormality handling process, the control unit 50 executes a process of outputting a warning indicating that the position of the second workpiece spindle 25 is out of the normal range ΔR. Fig. 7 is a diagram showing an example of a warning screen IM.

[0079] The warning screen IM includes, for example, a warning message MS indicating that the position of the second work spindle 25 is out of the normal range ΔR. The output destination of the warning screen IM may be the display of the additional processing device 100, or may be the display of a terminal different from the additional processing device 100 (for example, a management device or a server). Thereby, the operator can recognize that the position of the second work spindle 25 is out of the normal range ΔR.

[0080] <G. Driving mechanism of the additional processing device 100> Next, with reference to FIG. 8, the driving mechanism in the additional processing device 100 will be described. FIG. 8 is a diagram showing an example of the driving mechanism of the additional processing device 100.

[0081] As shown in FIG. 8, the additional processing device 100 includes a control unit 50 and driving units 210, 220, 230A, 230B, 240.

[0082] The control unit 50 controls various devices within the additional processing device 100. The device configuration of the control unit 50 is arbitrary. The control unit 50 may be composed of a single control unit or may be composed of 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). Further, the control unit 50 may include at least one of the motor drivers 211C, 221Z, 231X to 231Z, 231A, 231B, 241Y, 241Z, 241C shown in FIG. 8.

[0083] The driving unit 210 is a driving mechanism for rotationally driving the first work spindle 22. The driving unit 210 may be composed of a single driving unit or may be composed of a plurality of driving units. In the example of FIG. 8, the driving unit 210 is composed of a motor driver 211C and a motor 212C.

[0084] The motor driver 211C sequentially receives input of the target rotation angle or the target rotation speed of the first work spindle 22 from the control unit 50, and outputs a current according to the target rotation angle or the target rotation speed to the motor 212C. As a result, the work held by the first work spindle 22 rotates about the Z-axis direction as the center of rotation. The motor 212C may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0085] The drive unit 220 is a drive mechanism for driving the second work spindle 25. The drive unit 220 may be composed of a single drive unit, or may be composed of multiple drive units. In the example of Fig. 8, the drive unit 220 is composed of a motor driver 221Z and a motor 222Z.

[0086] The motor driver 221Z sequentially receives input of target positions for the second work spindle 25 from the control unit 50, and outputs a current corresponding to the target positions to the motor 222Z. This causes the motor 222Z to move the second work spindle 25 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.

[0087] The driving unit 230A is a driving mechanism for moving the position of the tool spindle 30. The above-mentioned laser head 140 is driven by being attached to the tool spindle 30. The driving unit 230A may be composed of a single driving unit, or may be composed of a plurality of driving units. In the example of FIG. 8, the driving unit 230A is composed of motor drivers 231X to 231Z and motors 232X to 232Z.

[0088] The motor driver 231X sequentially receives input of target positions of the tool spindle 30 in the X-axis direction from the control unit 50, and outputs a current corresponding to the target positions to the motor 232X. As a result, the motor 232X drives the tool spindle 30 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.

[0089] The motor driver 231Y sequentially receives input of target positions of the tool spindle 30 in the Y-axis direction from the control unit 50, and outputs a current corresponding to the target positions to the motor 232Y. As a result, the motor 232Y drives the tool spindle 30 to an arbitrary position in the Y-axis direction. The motor 232Y may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0090] The motor driver 231Z sequentially receives input of target positions of the tool spindle 30 in the Z-axis direction from the control unit 50, and outputs a current corresponding to the target positions to the motor 232Z. As a result, the motor 232Z moves the tool spindle 30 to an arbitrary position in the Z-axis direction. The motor 232Z may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0091] The driving unit 230B is a driving mechanism for rotationally driving the tool spindle 30. The driving unit 230B may be composed of a single driving unit, or may be composed of multiple driving units. In the example of Fig. 8, the driving unit 230B is composed of motor drivers 231A, 231B and motors 232A, 232B.

[0092] The motor driver 231A sequentially receives input of a target rotation angle or a target rotation speed of the tool spindle 30 centered on the Y-axis direction from the control unit 50, and outputs a current according to the target rotation angle or the target rotation speed to the motor 232A. The motor 232A drives the tool spindle 30 to rotate around the Y-axis direction. The motor 232A may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0093] The motor driver 231B sequentially receives an input of a target rotation angle or a target rotation speed of the tool spindle 30 about the axial direction of the tool spindle 30 as a rotation center from the control unit 50, and outputs a current according to the target rotation angle or the target rotation speed to the motor 232B. The motor 232B drives and rotates the tool spindle 30 about the axial direction of the tool spindle 30 as a rotation center. The motor 232B may be an AC motor, a stepping motor, a servo motor, or another type of motor.

[0094] The driving unit 240 is a driving mechanism for driving the tool rest 16 and the turret 18. The driving unit 240 may be composed of a single driving unit, or may be composed of multiple driving units. In the example of Fig. 8, the driving unit 240 is composed of motor drivers 241C, 241Y, and 241Z, and motors 242C, 242Y, and 242Z.

[0095] The motor driver 241C receives an input of a target value for the rotation angle of the turret 18 about the Z-axis direction, and outputs a current according to the target value to the motor 242C. In this way, the motor driver 241C controls the rotation angle of the turret 18 about the Z-axis direction as the center of rotation. The motor 242C may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0096] The motor driver 241Y sequentially receives the input of the target position of the tool rest 16 in the X-axis direction from the control unit 50, and outputs a current corresponding to the target position to the motor 242Y. Thereby, the motor 242Y moves the tool rest 16 to an arbitrary position in the X-axis direction. The motor 242Y may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0097] The motor driver 241Z sequentially receives the input of the target position of the tool rest 16 in the Z-axis direction from the control unit 50, and outputs a current corresponding to the target position to the motor 242Z. Thereby, the motor 242Z moves the tool rest 16 to an arbitrary position in the Z-axis direction. The motor 242Z may be an AC motor, a stepping motor, a servo motor, or any other type of motor.

[0098] <H. Hardware Configuration of Control Unit 50> Next, with reference to FIG. 9, the hardware configuration of the control unit 50 shown in FIG. 8 will be described. FIG. 9 is a diagram showing an example of the hardware configuration of the control unit 50.

[0099] As described above, the control unit 50 may be a CNC or a PLC. FIG. 9 shows the hardware configuration of the control unit 50 as a CNC.

[0100] 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.

[0101] The control circuit 101 is configured, for example, by at least one integrated circuit. The integrated circuit may be configured, for example, by at least one central processing unit (CPU), at least one graphics processing unit (GPU), at least one application specific integrated circuit (ASIC), at least one field programmable gate array (FPGA), or a combination thereof.

[0102] The control circuit 101 controls the operation of the control unit 50 by executing various programs such as a control program 122. The control program 122 is a program for implementing various processes described in this specification. Based on receiving an execution command for the control program 122, the control circuit 101 reads the control program 122 from the ROM 102 to the RAM 103. The RAM 103 functions as a working memory and temporarily stores various data required for the execution of the control program 122.

[0103] The communication interface 104 is an interface for realizing communication with various devices. The additional processing device 100 communicates with various drive units (e.g., the above-mentioned drive units 210, 220, 230A, 230B, 240, etc.) for realizing additional processing of the workpiece, for example, via the communication interface 104.

[0104] The auxiliary storage device 120 is a storage medium such as a hard disk or a flash memory. The auxiliary storage device 120 stores a control program 122 and the like. The storage location of the control program 122 is not limited to the auxiliary storage device 120, and may be stored in a storage area (e.g., cache memory) of the control circuit 101, the ROM 102, the RAM 103, an external device (e.g., a server), or the like.

[0105] Further, the control program 122 may be provided not as a single program but incorporated into a part of any program. In this case, various processes according to the present embodiment are realized in cooperation with any program. Even a program that does not include such a part of the module does not deviate from the gist of the control program 122 according to the present embodiment. Further, part or all of the functions provided by the control program 122 may be realized by dedicated hardware. Further, the control unit 50 may be configured in the form of a so-called cloud service in which at least one server executes a part of the processing of the control program 122.

[0106] <I. Control Flow of Additional Processing> Next, with reference to FIG. 10, the control flow of the additional processing will be described. FIG. 10 is a flowchart showing the flow of the additional processing.

[0107] The processing shown in FIG. 10 is realized, for example, when the control unit 50 of the additional processing device 100 executes the above-described control program 122. In other aspects, part or all of the processing may be executed by circuit elements or other hardware.

[0108] In step S110, the control unit 50 causes the first work spindle 22 and the second work spindle 25 to support the work W. As a result, the work W is disposed between the first work spindle 22 and the second work spindle 25.

[0109] In step S112, the control unit 50 starts the additional processing of the work W. More specifically, the control unit 50 controls the above-described drive unit 210 (see FIG. 8) to start the rotation of the work W centered on the Z-axis direction. Thereafter, the control unit 50 supplies the powder material PM to the work W and controls the operation of the laser head 140 so as to irradiate the work W with the laser beam LS.

[0110] In step S114, the control unit 50 controls the driving of the second work spindle 25 based on the above-mentioned torque feedback control. That is, the control unit 50 controls the above-mentioned motor 222Z so that the torque applied to the second work spindle 25 is constant. As a result, the second work spindle 25 moves along the Z-axis direction in accordance with the thermal expansion and thermal contraction of the workpiece W.

[0111] In step S120, the control unit 50 judges whether the position of the second work spindle is within the normal range ΔR (see FIG. 6) described above. If the control unit 50 judges that the position of the second work spindle is within the normal range ΔR (YES in step S120), it switches control to step S130. If not (NO in step S120), the control unit 50 switches control to step S150.

[0112] In step S130, the control unit 50 judges whether the laser head 140 has reached the processing end position. The processing end position of the laser head 140 is described, for example, in the processing program. When the control unit 50 judges that the laser head 140 has reached the processing end position (YES in step S130), the control unit 50 switches the control to step S132. When the control unit 50 has not reached the processing end position (NO in step S130), the control unit 50 returns the control to step S114.

[0113] In step S132, the additional processing by the laser head 140 is stopped. More specifically, the control unit 50 causes the laser head 140 to stop supplying the powder material and emitting the laser light. The control unit 50 also controls the drive unit 210 to stop the rotation of the first workpiece spindle 22. Furthermore, the control unit 50 continues the torque feedback control for a predetermined time after the completion of the additional processing.

[0114] In step S150, the control unit 50 executes the above-described abnormality handling process. As an example, the control unit 50 stops the additional processing by the laser head 140. As another example, the control unit 50 switches the control of the second work spindle 25 in the position feedback control to the position feedback control. As still another example, the control unit 50 outputs the above-described warning screen IM (see FIG. 7).

[0115] Note that in the above description, the control flow of the second work spindle 25 in the additional processing has been described, but the control unit 50 may make the control method of the second work spindle 25 different during the additional processing and the removal processing. As an example, the control unit 50 controls the second work spindle 25 by the above-described torque feedback control during the additional processing, and controls the second work spindle 25 by the above-described position feedback control during the removal processing.

[0116] <J. Others> The above-described torque feedback control can be realized by an arbitrary method. As an example, the "butting point stop function" that is standardly installed in the NC device is used. The "butting point stop function" is realized by the FXS command, the FXS command, and the FXST command.

[0117] The FXS command is usually a function for holding the work W on the second work spindle 25. The FXS command is a command for setting the target value of the torque. The FXST command is a command for setting the normal range ΔR of the second work spindle 25.

[0118] The FXS command, the FXS command, and the FXST command are usually commands used when holding the work W on the first work spindle 22 and the second work spindle 25, and are not used during the additional processing. By combining these commands, the torque feedback control during the additional processing is realized.

[0119] <K. Modification Example> Next, a modified method of controlling the second workpiece spindle 25 during additional machining will be described with reference to Fig. 11. Fig. 11 is a diagram for explaining a modified method of controlling the second workpiece spindle 25.

[0120] In the above-described embodiment, the control unit 50 controls the driving of the second workpiece spindle 25 based on torque feedback control, thereby moving the second workpiece spindle 25 in accordance with the thermal expansion and contraction of the workpiece W.

[0121] In contrast, in this modified example, the control unit 50 substantially disables the feedback control of the motor 222Z for controlling the position of at least the second work spindle 25 after the first work spindle 22 and the second work spindle 25 grip the workpiece W. The process of substantially disabling the feedback control of the motor 222Z can be realized in various ways. As one example, the set value of the current feedback gain set in the current feedback loop of the control system in the additional processing device 100 is set to zero so that feedback is not applied substantially. In this case, the position control of the second work spindle 25 is also disabled. As another example, when the current feedback gain is not switched, for example, the current feedback loop may be opened and control may be performed in an open loop. As yet another example, a function provided on the CNC side may be used to substantially prevent the generation of a resistance force against the change in the position of the second work spindle 25. Thereafter, the control unit 50 performs additional processing of the workpiece W. That is, by stopping the control of the motor 222Z, the second work spindle 25 is in a state where it maintains its position in the Z-axis direction by its own weight. As a result, the second workpiece spindle 25 is brought into a state in which it can be moved manually. Therefore, the second workpiece spindle 25 can move in accordance with the thermal expansion and contraction of the workpiece W.

[0122] More specifically, in step S21 before the start of additional machining, the motor 222Z is ​​driven to move the second work spindle 25 closer to the first work spindle 22. As a result, one side of the work W is gripped by the first work spindle 22, and the other side of the work W is gripped by the second work spindle 25.

[0123] Then, in step S22, the control unit 50 starts additional processing of the workpiece W while stopping control of the motor 222Z. More specifically, the control unit 50 controls the above-mentioned drive unit 210 (see FIG. 8) to start rotating the workpiece W. Thereafter, the control unit 50 supplies the powder material PM to the workpiece W and controls the operation of the laser head 140 to irradiate the workpiece W with the laser light LS.

[0124] Preferably, in this modified example as well, the control unit 50 sequentially acquires the current position of the second workpiece spindle 25 during additional machining of the workpiece W, and monitors whether or not the current position is within the normal range ΔR. The method of setting the normal range ΔR is as described above, and therefore the description will not be repeated. When the current position of the second workpiece spindle 25 falls outside the normal range ΔR, the control unit 50 executes the above-described abnormality handling process.

[0125] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0126] 11 bed, 16 tool rest, 18 turret, 21 first support, 22 first work spindle, 23 chuck mechanism, 24 second support, 25 second work spindle, 26 chuck mechanism, 30 tool spindle, 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 control program, 130 cover body, 140 laser head, 142 head body, 146 laser nozzle, 200 operation panel, 210 drive unit, 211C motor driver, 212C motor, 220 drive unit, 221Z motor driver, 222Z motor, 230A drive unit, 230B drive unit, 231A motor driver, 231B motor driver, 231X Motor driver, 231Y motor driver, 231Z motor driver, 232A motor, 232B motor, 232X motor, 232Y motor, 232Z motor, 240 drive unit, 241C motor driver, 241Y motor driver, 241Z motor driver, 242C motor, 242Y motor, 242Z motor, 322 sensor, 324 position sensor, AR machining area, AX1 rotation axis, AX2 rotation axis, AX3 rotation axis, DR door, F focus, IM warning screen, LS laser light, MP molten pool, MS warning message, PM powder material, SL layer, W workpiece, ΔR normal range.

Claims

1. An additional processing device for performing additional processing on a workpiece, A laser head capable of performing additional processing on a workpiece by supplying a powder material to the workpiece and irradiating the workpiece with a laser light; a first support portion for supporting one side of the workpiece in a direction of a predetermined axis and for supporting the workpiece rotatably about the predetermined axis; a second support portion for supporting the other side of the workpiece in the direction of the predetermined axis and for supporting the workpiece rotatably around the predetermined axis; A drive unit for moving the second support unit along a direction of the predetermined axis; A first detector for detecting a physical quantity correlated with a torque applied to the drive unit; A control unit for controlling the additional processing device, The control unit performs a process of controlling the drive unit so that the physical quantity detected by the first detection unit approaches a predetermined target value during additional processing of the workpiece or during cooling of the workpiece.

2. The additional processing device further includes a second detection unit for detecting a position of the second support unit in a direction of the predetermined axis, The control unit further includes: a process of monitoring whether the position is within a preset range while executing the process of controlling the drive unit; 2. The additional machining device according to claim 1, further comprising a step of: if the position is out of the preset range, a predetermined abnormality handling process is carried out.

3. 3. The additional processing device according to claim 2, wherein the abnormality handling process includes a process of switching from a process of controlling the drive unit so that the physical quantity approaches the predetermined target value to a process of controlling the drive unit so that the position detected by the second detection unit approaches a target position.

4. 4. The additional machining apparatus according to claim 2, wherein the abnormality handling process includes a process of outputting a warning indicating that the position is outside the preset range.

5. the first support portion is a first work spindle having a chuck mechanism for gripping one side of the workpiece, 4. The additional machining device according to claim 1, wherein the second support portion is a second work spindle having a chuck mechanism for gripping the other side of the work.

6. The first support portion is a workpiece spindle having a chuck mechanism for gripping one side of the workpiece, 4. The additional processing device according to claim 1, wherein the second support portion is a tailstock having a tailstock mechanism for tail-pushing the other side of the workpiece.

7. An additional processing device for performing additional processing on a workpiece, A laser head capable of performing additional processing on a workpiece by supplying a powder material to the workpiece and irradiating the workpiece with a laser light; a first support portion for gripping one side of the workpiece in a direction of a predetermined axis and for gripping the workpiece rotatably about the predetermined axis; a second support portion for gripping the other side of the workpiece in the direction of the predetermined axis and for gripping the workpiece rotatably around the predetermined axis; A drive unit for moving the second support unit along a direction of the predetermined axis; A control unit for controlling the additional processing device, The control unit executes a process to disable the control process of the drive unit during additional processing of the workpiece or during cooling of the workpiece.

8. A method for additional processing a workpiece by an additional processing device, comprising: The additional processing device is A laser head capable of performing additional processing on a workpiece by supplying a powder material to the workpiece and irradiating the workpiece with a laser light; a first support portion for supporting one side of the workpiece in a direction of a predetermined axis and for supporting the workpiece rotatably about the predetermined axis; a second support portion for supporting the other side of the workpiece in the direction of the predetermined axis and for supporting the workpiece rotatably around the predetermined axis; A drive unit for moving the second support unit along a direction of the predetermined axis; a first detection unit for detecting a physical quantity correlated with a torque applied to the drive unit, The additional processing method includes a step of controlling the drive unit so that the physical quantity detected by the first detection unit approaches a predetermined target value during additional processing of the workpiece or during cooling of the workpiece.

9. A program for additive machining of a workpiece by an additive machining device, The additional processing device is A laser head capable of performing additional processing on a workpiece by supplying a powder material to the workpiece and irradiating the workpiece with a laser light; a first support portion for supporting one side of the workpiece in a direction of a predetermined axis and for supporting the workpiece rotatably about the predetermined axis; a second support portion for supporting the other side of the workpiece in the direction of the predetermined axis and for supporting the workpiece rotatably around the predetermined axis; A drive unit for moving the second support unit along a direction of the predetermined axis; a first detection unit for detecting a physical quantity correlated with a torque applied to the drive unit, The additional processing program causes the additional processing device to execute a process of controlling the drive unit so that the physical quantity detected by the first detection unit approaches a predetermined target value during additional processing of the workpiece or cooling of the workpiece.

Images