Workpiece machining method and machining machine

Abstract

A method for machining a workpiece includes: holding a workpiece (W) by a first holding portion (51) and a second holding portion (52) disposed apart from each other; a step for performing additional processing on the workpiece (W) by supplying a material powder (P) to the workpiece (W) held by the first holding unit (51) and the second holding unit (52) and irradiating the workpiece (W) with a laser light (L); and a step for relatively moving the first holding section (51) and the second holding section (52) in the direction away from each other during at least a part of the period of the step for performing additional machining on the workpiece (W).

Description

Technical Field

[0001] The invention relates to a workpiece processing method and a processing machine. Background Art

[0002] For example, Japanese Patent Gazette No. 6810823 (Patent Document 1) discloses an additional processing method for a workpiece, which includes: a step of applying stress to a workpiece having a first linear expansion coefficient; a step of supplying material powder having a second linear expansion coefficient different from the first linear expansion coefficient to the workpiece while maintaining the state of applying stress to the workpiece, and irradiating the workpiece with laser; and a step of relaxing the stress on the workpiece and cooling the workpiece after the steps of supplying material powder and irradiating the laser.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6810823 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] As disclosed in Patent Document 1, there is known a method for processing a workpiece into a three-dimensional shape by using a directed energy deposition method in which a laser is irradiated while a material powder is supplied to the workpiece.

[0008] In such a workpiece processing method, in order to support the workpiece to be processed, the workpiece is held by a first holding portion and a second holding portion that are disposed separately from each other. In this case, when the workpiece is irradiated with laser light, the workpiece thermally expands, and the surface of the workpiece is deformed between the first holding portion and the second holding portion. As a result, the following problem may occur: the material powder cannot be supplied to the surface of the workpiece as intended, and the processing accuracy of the workpiece is reduced.

[0009] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a workpiece processing method and a processing machine capable of maintaining high processing accuracy of the workpiece in additional processing of the workpiece using a directional energy deposition method.

[0010] Solutions for solving problems

[0011] The workpiece processing method according to the invention comprises: a step of holding the workpiece by using a first holding portion and a second holding portion that are separately arranged from each other; a step of performing additional processing on the workpiece by supplying material powder to the workpiece held by the first holding portion and the second holding portion and irradiating the workpiece with laser; and a step of moving the first holding portion and the second holding portion relative to each other in directions away from each other during at least a portion of the step of performing additional processing on the workpiece.

[0012] According to the workpiece processing method thus constructed, during the additional processing, the workpiece is irradiated with laser light, so that the workpiece thermally expands between the first holding portion and the second holding portion. In this case, during at least a portion of the step of performing the additional processing on the workpiece, the first holding portion and the second holding portion are relatively moved in a direction away from each other, thereby suppressing the surface of the workpiece from being deformed between the first holding portion and the second holding portion. As a result, material powder can be supplied to the surface of the workpiece as intended, and therefore, the processing accuracy of the workpiece can be maintained at a high level.

[0013] In addition, it is preferred that the first holding portion is a first workpiece spindle for rotating the workpiece around a predetermined axis. The second holding portion is a second workpiece spindle that is arranged relative to the first workpiece spindle in the axial direction of the predetermined axis and can slide in the axial direction of the predetermined axis to rotate the workpiece around the predetermined axis. The step of relatively moving the first holding portion and the second holding portion includes the step of sliding the second workpiece spindle in the axial direction of the predetermined axis.

[0014] According to the work processing method configured in this manner, it is possible to suppress surface deformation of the work due to thermal expansion of the work during additional processing with a simple structure.

[0015] In addition, it is preferred that the method for processing a workpiece further comprises: a step of detecting the temperature of the workpiece during at least a portion of the step of performing additional processing on the workpiece; and a step of calculating the amount of thermal expansion of the workpiece based on the detected temperature of the workpiece. The step of relatively moving the first holding portion and the second holding portion includes the step of relatively moving the first holding portion and the second holding portion in a direction away from each other by a distance corresponding to the calculated amount of thermal expansion of the workpiece.

[0016] According to the workpiece processing method configured in this manner, the amount of thermal expansion of the workpiece during additional processing can be accurately grasped, and thus surface deformation of the workpiece can be more reliably suppressed.

[0017] Preferably, the workpiece processing method further comprises, after the step of additionally processing the workpiece, the step of relatively moving the first holding portion and the second holding portion in directions approaching each other, while cooling the workpiece.

[0018] According to the work processing method configured in this way, the first holding portion and the second holding portion are relatively moved in a direction approaching each other according to the thermal contraction of the work during cooling, thereby suppressing the generation of residual stress in the work.

[0019] The processing machine according to the invention is a processing machine for performing additional processing of a workpiece. The processing machine comprises: an additional processing head, which supplies material powder to the workpiece and irradiates laser light; a first workpiece spindle, which is used to rotate the workpiece around a predetermined axis; a second workpiece spindle, which is arranged relative to the first workpiece spindle in the axial direction of the predetermined axis and can slide in the axial direction of the predetermined axis, and is used to rotate the workpiece around the predetermined axis; and a control device, which controls the processing machine. The control device controls the movement of the additional processing head so as to perform additional processing on the workpiece by supplying material powder to the workpiece held by the first workpiece spindle and the second workpiece spindle and irradiating laser light; and controls the sliding movement of the second workpiece spindle so that the second workpiece spindle moves in a direction away from the first workpiece spindle during at least a portion of the period when the workpiece is subjected to additional processing.

[0020] According to the processing machine configured in this manner, material powder can be supplied onto the surface of the workpiece as intended, and therefore, the processing accuracy of the workpiece can be maintained high.

[0021] Effects of the Invention

[0022] As described above, according to the present invention, it is possible to provide a workpiece processing method and a processing machine capable of maintaining high processing accuracy of a workpiece in additional processing of the workpiece using a directional energy deposition method. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a front view showing the processing machine.

[0024] Figure 2 It means in Figure 1 A three-dimensional diagram showing the situation in the processing area during additional processing in a processing machine.

[0025] Figure 3 This is a front view showing a first step of executing the method for processing a workpiece in the present embodiment.

[0026] Figure 4 It is a front view showing the second step of executing the workpiece processing method in this embodiment.

[0027] Figure 5 It is a front view showing the third step of executing the workpiece processing method in this embodiment.

[0028] Figure 6 It is a front view showing the fourth step of executing the workpiece processing method in this embodiment.

[0029] Figure 7 It means in Figure 1 and Figure 2 Block diagram of a control system associated with additional processing of a workpiece in a processing machine.

[0030] Figure 8 It means use Figure 1 and Figure 2 The present invention is a flowchart of the process of executing the steps of the method for processing a workpiece in the present embodiment using a processing machine in the present invention.

[0031] Fig. 9 It means Figure 7 A block diagram of a modified example of a control system associated with additional processing of a workpiece.

[0032] Fig.10 It means execution Figure 8 A flowchart of a modified example of the flow of steps in a method for processing a workpiece.

[0033] Fig.11 This is a perspective view showing an example of a workpiece to be subjected to additional processing. DETAILED DESCRIPTION

[0034] Embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings referred to below, the same or corresponding components are denoted by the same reference numerals.

[0035] Figure 1 This is a front view showing the processing machinery. Figure 1 In the figure, the interior of the processing machine is shown by seeing through a cover constituting the appearance of the processing machine. Figure 2 It means in Figure 1 A three-dimensional diagram showing the situation in the processing area during additional processing in a processing machine.

[0036] Reference Figure 1 and Figure 2 The processing machine 100 is an AM / SM hybrid processing machine that can perform additional processing (AM (Additive manufacturing) processing) of a workpiece and removal processing (SM (Subtractive manufacturing) processing) of a workpiece. The processing machine 100 has a turning function using a fixed tool and a milling function using a rotating tool as SM processing functions. The processing machine 100 is an NC (Numerically Controlled) processing machine that automates various operations for processing a workpiece through numerical control performed by a computer.

[0037] In this specification, the axis parallel to the left-right direction (width direction) of the processing machine 100 and extending in the horizontal direction is called the "Z axis", the axis parallel to the front-back direction (depth direction) of the processing machine 100 and extending in the horizontal direction is called the "Y axis", and the axis extending in the vertical direction is called the "X axis". Figure 1 The right direction in is called the "+Z axis direction", and the left direction is called the "-Z axis direction". Figure 1 The front direction of the paper is called the "+Y axis direction", and the depth direction is called the "-Y axis direction". Figure 1 The upward direction is referred to as the "+X axis direction", and the downward direction is referred to as the "-X axis direction".

[0038] First, a basic structure of a processing machine 100 used for the workpiece processing method in this embodiment will be described. The processing machine 100 includes a base 136 , a first spindle head 111 , a second spindle head 116 , a tool spindle 121 , and a lower tool post 131 .

[0039] The base 136 is a base member for supporting the first spindle stage 111, the second spindle stage 116, the tool spindle 121, the lower tool rest 131, etc., and is installed on the floor of a factory, etc. The first spindle stage 111 (the first workpiece spindle 112 discussed later), the second spindle stage 116, the tool spindle 121, and the lower tool rest 131 are installed in a processing area 200 divided by a splash guard member 205.

[0040] The processing area 200 is a space for performing removal processing and additional processing of a workpiece, and is sealed so that foreign matter such as chips, cutting oil, and smoke generated by these workpiece processing does not leak to the outside of the processing area 200.

[0041] The first spindle stage 111 and the second spindle stage 116 are arranged opposite to each other in the Z-axis direction. The first spindle stage 111 and the second spindle stage 116 respectively have a first workpiece spindle 112 and a second workpiece spindle 117 for rotating the workpiece during turning using a fixed tool or holding the workpiece during milling or removal using a rotating tool. The first workpiece spindle 112 is arranged to be rotatable around a center axis 201A parallel to the Z-axis, and the second workpiece spindle 117 is arranged to be rotatable around a center axis 201B parallel to the Z-axis. The center axis 201A and the center axis 201B extend on the same straight line and constitute the center axis 201.

[0042] The first workpiece spindle 112 and the second workpiece spindle 117 respectively have a chuck 113 and a chuck 118 for detachably holding a workpiece. In the present embodiment, the end face of the module supporting the claw portion for holding the workpiece in the chuck 113 is referred to as the spindle end face 112f of the first workpiece spindle 112, and the end face of the module supporting the claw portion for holding the workpiece in the chuck 118 is referred to as the spindle end face 117f of the second workpiece spindle 117. In this case, the distance in the Z-axis direction between the spindle end face 112f of the first workpiece spindle 112 and the spindle end face 117f of the second workpiece spindle 117 corresponds to the spindle-to-spindle distance H between the first workpiece spindle 112 and the second workpiece spindle 117.

[0043] like Figure 2 As shown in FIG. 1 , a workpiece W to be processed is held by a first workpiece spindle 112 and a second workpiece spindle 117. The workpiece W is formed of a metal material such as stainless steel.

[0044] The workpiece W extends on the axis of the central axis 201. One end of the central axis 201 of the workpiece W in the axial direction is held by the chuck 113, and the other end of the central axis 201 of the workpiece W in the axial direction is held by the chuck 118. The first workpiece spindle 112 and the second workpiece spindle 117 are driven to rotate synchronously with each other, so that the workpiece W can rotate around the central axis 201.

[0045] The second spindle stage 116 (second workpiece spindle 117) can slide in the Z-axis direction by using various conveying mechanisms, guiding mechanisms, and servo motors. When the second workpiece spindle 117 moves in the direction away from the first workpiece spindle 112 (+Z-axis direction), the spindle distance H between the first workpiece spindle 112 and the second workpiece spindle 117 increases, and when the second workpiece spindle 117 moves in the direction close to the first workpiece spindle 112 (-Z-axis direction), the spindle distance H between the first workpiece spindle 112 and the second workpiece spindle 117 decreases.

[0046] The tool spindle (upper tool rest) 121 rotates the rotary tool during milling. The tool spindle 121 is rotatable about a central axis 203 parallel to the X-axis-Z-axis plane. The tool spindle 121 is provided with a clamping mechanism for holding the rotary tool in a detachable manner.

[0047] The tool spindle 121 is supported on the base 136 by a column (not shown) or the like. The tool spindle 121 can slide in the X-axis direction, the Y-axis direction, and the Z-axis direction by various conveying mechanisms, guide mechanisms, and servo motors provided on the column or the like. According to such a structure, the processing position of the rotary tool mounted on the tool spindle 121 moves three-dimensionally.

[0048] The tool spindle 121 is also configured to be rotatable about a rotation center axis 204 parallel to the Y axis (B-axis rotation). The rotation range of the tool spindle 121 is a posture in which the spindle end face 123 of the tool spindle 121 faces downward ( Figure 1 Neutralization Figure 2 The rotation range of the tool spindle 121 is preferably from Figure 1 and Figure 2 The posture shown in the figure is within a range of ±90°.

[0049] In addition, although Figure 1 Although not shown, an automatic tool changer (ATC: Automatic Tool Changer) for automatically replacing a tool mounted on the tool spindle 121 and a tool magazine for storing replacement tools mounted on the tool spindle 121 are provided around the first spindle stage 111 .

[0050] The lower tool rest 131 is used to install a plurality of fixed tools for turning. The lower tool rest 131 is a so-called turret shape, and a plurality of fixed tools are radially installed and rotated to release.

[0051] More specifically, the lower tool holder 131 has a rotating portion 132. The rotating portion 132 is provided so as to be rotatable around a central axis 206 parallel to the Z axis. A plurality of tool holders for holding fixed tools are installed at positions spaced apart in the circumferential direction around the central axis 206. The rotating portion 132 rotates around the central axis 206, so that the fixed tool held in the tool holder moves in the circumferential direction, and the fixed tool used for turning is released.

[0052] The lower tool rest 131 is supported by a saddle (not shown) on a base 136. The lower tool rest 131 can slide in the X-axis direction and the Z-axis direction by various conveying mechanisms, guide mechanisms, and servo motors provided to the saddle.

[0053] The processing machine 100 further includes an additional processing head 21. The additional processing head 21 supplies material powder P to the workpiece W and irradiates the workpiece W with laser light L, thereby performing additional processing (directed energy deposition). As the material powder P, for example, metal powder such as cobalt-based alloy or SKD material can be used. The material powder P may be the same material as the material of the workpiece W, or may be a material different from the material of the workpiece W.

[0054] like Figure 2 As shown, the additional processing head 21 has a nozzle 26. The nozzle 26 is composed of a pipe member through which the material powder P can flow. The nozzle 26 sprays the material powder P toward the workpiece W.

[0055] The additional processing head 21 is configured to be detachable relative to the tool spindle 121. During additional processing, the additional processing head 21 is mounted on the tool spindle 121. The tool spindle 121 slides in the X-axis direction, the Y-axis direction, and the Z-axis direction, and the processing position of the additional processing performed by the additional processing head 21 moves three-dimensionally. Moreover, as the tool spindle 121 rotates around the rotation center axis 204, the additional processing head 21 also rotates integrally with the tool spindle 121 around the rotation center axis 204. As a result, the direction of the additional processing performed by the additional processing head 21 (the irradiation direction of the laser L relative to the workpiece W) can be freely changed.

[0056] During the removal process, the additional processing head 21 is separated from the tool spindle 121 and stored in a head frame (not shown).

[0057] The tool spindle 121 is provided with a clamping mechanism, which is actuated when the additional processing head 21 is mounted on the tool spindle 121, thereby coupling the additional processing head 21 to the tool spindle 121. An example of the clamping mechanism is a mechanism that uses elastic force to obtain a clamped state and uses hydraulic pressure to obtain an unclamped state.

[0058] like Figure 1 As shown, the processing machine 100 further includes a powder feeder 70 , a laser oscillator 76 , and a pipeline body 24 .

[0059] The powder feeder 70 introduces the material powder used for the additional processing toward the additional processing head 21 in the processing area 200. The powder feeder 70 includes a powder hopper 72 and a mixing unit 71. The powder hopper 72 forms a closed space for storing the material powder used for the additional processing. The mixing unit 71 mixes the material powder stored in the powder hopper 72 with a gas for a carrier of the material powder.

[0060] The laser oscillator 76 oscillates the laser used for the additional processing. The pipeline body 24 is composed of an optical fiber for guiding the laser from the laser oscillator 76 to the additional processing head 21, a pipe for guiding the material powder from the powder feeder 70 to the additional processing head 21, an air pipe serving as a flow path for air, a gas pipe serving as a flow path for inert gas, a cooling pipe serving as a flow path for refrigerant, electrical wiring, and a pipe member for storing these.

[0061] Next, a method for processing a workpiece in this embodiment will be described. Figure 3 to Figure 6 It is a front view showing the steps of executing the method for processing a workpiece in this embodiment.

[0062] Reference Figure 3 to Figure 6 The workpiece processing method in this embodiment has the following steps: Figure 3As shown, the steps of holding the workpiece W by using the first holding portion 51 (the first workpiece spindle 112) and the second holding portion 52 (the second workpiece spindle 117); Figure 4 As shown in FIG. 1 , a step of performing additional processing on the workpiece W by supplying material powder P to the workpiece W held by the first holding portion 51 and the second holding portion 52 and irradiating the workpiece W with laser light L; and Figure 5 As shown in FIG. 1 , during at least a portion of the step of performing additional processing on the workpiece W, the first holding portion 51 and the second holding portion 52 are relatively moved in directions away from each other.

[0063] When the workpiece W is irradiated with the laser light L during the additional processing of the workpiece W, the workpiece W thermally expands. The workpiece W is held by the first holding portion 51 and the second holding portion 52, and therefore, along with the thermal expansion of the workpiece W, the surface fa of the workpiece W on the side irradiated with the laser light L is deformed so as to protrude outward in the radial direction of the central axis 201. In this case, the material powder P may not be stacked at the intended position on the surface fa of the workpiece W, and the accuracy of the additional processing of the workpiece W may be reduced.

[0064] In contrast, in the workpiece processing method of the present embodiment, by relatively moving the first holding portion 51 and the second holding portion 52 in directions away from each other during at least a portion of the step of performing additional processing on the workpiece W, it is possible to suppress deformation of the surface fa of the workpiece W due to thermal expansion of the workpiece W. As a result, the material powder P can be stacked at an intended position on the surface fa of the workpiece W, and thus, the workpiece W can be subjected to high-precision additional processing.

[0065] Furthermore, the relative movement between the first holding portion 51 and the second holding portion 52 may be performed during a portion of the additional processing of the workpiece W. The relative movement between the first holding portion 51 and the second holding portion 52 may be performed continuously or intermittently during the additional processing of the workpiece W.

[0066] like Figure 4 As shown, the workpiece processing method in this embodiment further comprises: a step of detecting the temperature of the workpiece W during at least a portion of the step of performing additional processing on the workpiece W; and a step of calculating the thermal expansion amount of the workpiece W based on the detected temperature of the workpiece W. Figure 5 As shown, in the step of relatively moving the first holding portion 51 and the second holding portion 52 , the first holding portion 51 and the second holding portion 52 are relatively moved in directions away from each other by a distance corresponding to the calculated amount of thermal expansion of the workpiece W.

[0067] According to such a configuration, the amount of thermal expansion of the workpiece W during additional processing can be accurately grasped based on the temperature of the workpiece W. Thus, deformation of the surface fa of the workpiece W due to thermal expansion of the workpiece W can be more reliably suppressed.

[0068] like Figure 6 As shown, the workpiece processing method further includes, after the step of performing additional processing on the workpiece W, the step of relatively moving the first workpiece spindle 112 and the second workpiece spindle 117 in directions approaching each other and cooling the workpiece W.

[0069] After the additional processing on the workpiece W is completed, the workpiece W is cooled to a certain temperature and then removed from the first holding portion 51 and the second holding portion 52. In this case, if the workpiece W shrinks thermally as it cools, residual stress may be generated in the workpiece W because the workpiece W is held by the first holding portion 51 and the second holding portion 52.

[0070] In contrast, in the workpiece processing method of the present embodiment, the first holding portion 51 and the second holding portion 52 are relatively moved toward each other in accordance with the thermal contraction of the workpiece W during cooling. Thus, the generation of residual stress in the workpiece W can be suppressed.

[0071] Next, as a more specific example of the method for processing a workpiece in this embodiment, a method using Figure 1 and Figure 2 A case where the workpiece processing method of this embodiment is executed by the processing machine 100.

[0072] Figure 7 It means in Figure 1 and Figure 2 Block diagram of the control system associated with additional processing of the workpiece in the processing machine. Figure 7 The processing machine 100 further includes a control device 81 .

[0073] The control device 81 controls the processing machine 100. The control device 81 is a control panel provided in the processing machine 100 and used to control various operations in the processing machine 100.

[0074] The control device 81 includes a program storage unit 82 , a program execution unit 83 , a tool spindle control unit 84 , an additional machining control unit 85 , a first workpiece spindle control unit 86 , and a second workpiece spindle control unit 87 .

[0075] The program storage unit 82 stores an execution program (numerical control program) for workpiece machining written by an operator of the machining machine 100. As an example, the program storage unit 82 is a flash memory.

[0076] The program execution unit 83 executes the execution program stored in the program storage unit 82. The program execution unit 83 reads the execution program command and outputs control signals to the tool spindle control unit 84, the additional machining control unit 85, the first workpiece spindle control unit 86, and the second workpiece spindle control unit 87, respectively.

[0077] The tool spindle control unit 84 controls the tool spindle conveying motor 89 for sliding the tool spindle 121 in the X-axis direction, the Y-axis direction, and the Z-axis direction, and the tool spindle rotating motor 90 for performing B-axis rotation of the tool spindle 121, according to the control signal from the program execution unit 83. The additional processing control unit 85 controls the laser oscillator 76 for supplying laser light to the additional processing head 21, and the powder feeder 70 for supplying material powder to the additional processing head 21, according to the control signal from the program execution unit 83.

[0078] The first workpiece spindle control unit 86 controls the first workpiece spindle rotation motor 91 for rotating the first workpiece spindle 112 according to the control signal from the program execution unit 83. The second workpiece spindle control unit 87 controls the second workpiece spindle rotation motor 92 for rotating the second workpiece spindle 117 and the second workpiece spindle conveying motor 93 for sliding the second workpiece spindle 117 in the Z-axis direction according to the control signal from the program execution unit 83.

[0079] The control device 81 further includes a storage unit 96. The storage unit 96 stores data on the relationship between the type of metal used for the workpiece and the linear expansion coefficient of each metal.

[0080] The processing machine 100 further includes an operation unit 95 and a temperature detection unit 94. The operation unit 95 is provided outside the processing area 200. The operation unit 95 includes various buttons and switches used by the operator to operate the processing machine 100, and a display unit that indicates the processing state of the workpiece in the processing machine 100. The operation unit 95 is configured so that the type of metal used for the workpiece and the total length of the workpiece in the Z-axis direction can be input.

[0081] The temperature detection unit 94 is provided in the processing area 200. The temperature detection unit 94 is configured to detect the temperature of the workpiece during the additional processing. The temperature detection unit 94 detects the temperature of the workpiece in a non-contact manner. The temperature detection unit 94 is, for example, an infrared temperature sensor that detects infrared radiation energy released from the surface of the workpiece, converts it into temperature, and outputs it. The temperature detection unit 94 outputs the detected temperature of the workpiece to the second workpiece spindle control unit 87.

[0082] Figure 8 It means use Figure 1 and Figure 2 The present invention is a flowchart of the process of executing the steps of the method for processing a workpiece in the present embodiment using a processing machine in the present invention.

[0083] Reference Figure 3 , Figure 7 as well as Figure 8First, the workpiece W is held by the first workpiece spindle 112 and the second workpiece spindle 117 (S101). In this step, the workpiece W is arranged between the first workpiece spindle 112 and the second workpiece spindle 117. The chuck 113 and the chuck 118 hold one end and the other end of the workpiece W in the Z-axis direction, respectively.

[0084] The type of metal used for the workpiece W and the total length S of the workpiece W in the Z-axis direction are input to the operation unit 95 ( S102 ). The operation unit 95 outputs the input type of metal and total length S to the second workpiece spindle control unit 87 .

[0085] Next, the second workpiece spindle control unit 87 determines the linear expansion coefficient α of the workpiece W ( S103 ). In this step, the second workpiece spindle control unit 87 determines the linear expansion coefficient α of the workpiece W by comparing the type of metal used for the workpiece W obtained in step S102 with the data stored in the storage unit 96 .

[0086] The temperature detection unit 94 detects the temperature T (n=0) of the workpiece W ( S104 ). The temperature detection unit 94 outputs the detected temperature T (n=0) of the workpiece W to the second workpiece spindle control unit 87 .

[0087] Reference Figure 4 , Figure 7 as well as Figure 8 Then, the tool spindle control unit 84 and the additional processing control unit 85 start additional processing of the workpiece W ( S105 ). In this step, the additional processing of the workpiece W is performed according to the execution program stored in the program storage unit 82 .

[0088] More specifically, the tool spindle control unit 84 controls the tool spindle conveying motor 89 and the tool spindle rotating motor 90 so that the additional processing head 21 mounted on the tool spindle 121 is arranged directly above the workpiece W, and the spindle end face 123 of the tool spindle 121 faces the -X axis direction. The first workpiece spindle control unit 86 and the second workpiece spindle control unit 87 control the first workpiece spindle rotating motor 91 and the second workpiece spindle rotating motor 92, respectively, so that the surface fa of the workpiece W faces the +X axis direction. The additional processing control unit 85 controls the laser oscillator 76 and the powder feeder 70 so that the laser light L and the material powder P are supplied from the additional processing head 21 toward the surface fa of the workpiece W. The tool spindle control unit 84 controls the tool spindle conveying motor 89 so that the additional processing head 21 moves according to the execution program stored in the program storage unit 82.

[0089] Next, the temperature detection unit 94 detects the temperature T (n=1) of the workpiece W after a predetermined time has passed since the start of the additional machining in step S105 ( S106 ). The temperature detection unit 94 outputs the detected temperature T (n=1) of the workpiece W to the second workpiece spindle control unit 87 .

[0090] Next, the second workpiece spindle control unit 87 calculates the amount of thermal expansion ΔU (n=1) in the Z-axis direction of the workpiece W (S107). In this step, the second workpiece spindle control unit 87 calculates the amount of thermal expansion ΔU (n=1) in the Z-axis direction of the workpiece W by substituting the linear expansion coefficient α of the workpiece W determined in step S103, the temperature T (n=0) of the workpiece W detected by the temperature detection unit 94 in step S104, and the temperature T (n=1) of the workpiece W detected by the temperature detection unit 94 in step S106 into the following formula.

[0091] ΔU(n)=α*S*[T(n)-T(n-1)]

[0092] That is, the workpiece W irradiated with the laser light L is extended by ΔU (n=1) in the Z-axis direction during a period of time that has passed since the start of the additional processing.

[0093] Reference Figure 5 , Figure 7 as well as Figure 8 Next, the second workpiece spindle control unit 87 controls the second workpiece spindle transport motor 93 to move the second workpiece spindle 117 in the +Z-axis direction by ΔU (n=1) calculated in step S107 ( S108 ).

[0094] Then, after step S108 is completed and a predetermined time has passed since step S106, the process returns to step S106. The temperature detection unit 94 and the second workpiece spindle control unit 87 repeatedly perform steps S106, S107, and S108 during the additional processing of the workpiece W started in step S105. Each time steps S106, S107, and S108 are repeated, the value of n in the above formula takes an integer value that increases from 1. As the second workpiece spindle 117 moves in the +Z axis direction, the spindle distance H between the first workpiece spindle 112 and the second workpiece spindle 117 increases (H2>H1).

[0095] In order to simplify the description, the above calculation method is based on the assumption that the temperature distribution of the workpiece W is uniform in the Z-axis direction. In fact, in the temperature distribution in the Z-axis direction of the workpiece W, the irradiation area of ​​the laser L is set to the highest temperature, and a gradient is generated that decreases as the temperature is farther away from the irradiation area of ​​the laser L. When the thermal expansion amount ΔU(n) of the workpiece W is obtained while considering such a temperature distribution, for example, the workpiece W is divided into a plurality of areas arranged in the Z-axis direction, the representative temperature of the workpiece W is detected in each area, and the thermal expansion amount of the workpiece W in each area is calculated based on the detected representative temperature. Finally, the thermal expansion amounts of the workpiece in the plurality of areas are all added up.

[0096] Reference Figure 6 to Figure 8 Then, the tool spindle control unit 84 and the additional processing control unit 85 etc. complete the additional processing of the workpiece W. The temperature detection unit 94 detects the temperature T (m=0) of the workpiece W when the additional processing is completed (S109). The temperature detection unit 94 outputs the detected temperature T (m=0) of the workpiece W to the second workpiece spindle control unit 87. From then on, the workpiece W subjected to the additional processing is placed in a state held by the first workpiece spindle 112 and the second workpiece spindle 117, so that the workpiece W is cooled.

[0097] Next, the temperature detection unit 94 detects the temperature T (m=1) of the workpiece W after a predetermined time has passed since the additional machining in step S109 was completed ( S110 ). The temperature detection unit 94 outputs the detected temperature T (m=1) of the workpiece W to the second workpiece spindle control unit 87 .

[0098] Next, the second workpiece spindle control unit 87 calculates the amount of thermal contraction ΔV (m=1) in the Z-axis direction of the workpiece W (S111). In this step, the second workpiece spindle control unit 87 calculates the amount of thermal contraction ΔV (m=1) in the Z-axis direction of the workpiece W by substituting the linear expansion coefficient α of the workpiece W determined in step S103, the temperature T (m=0) of the workpiece W detected by the temperature detection unit 94 in step S109, and the temperature T (m=1) of the workpiece W detected by the temperature detection unit 94 in step S110 into the following formula.

[0099] ΔV(m)=α*S*[T(m-1)-T(m)]

[0100] That is, the workpiece W placed in the processing area 200 is shortened by ΔV (m=1) in the Z-axis direction during a predetermined time period after the additional processing is completed.

[0101] Next, the second workpiece spindle control unit 87 controls the second workpiece spindle transport motor 93 so as to move the second workpiece spindle 117 in the −Z-axis direction by ΔV (m=1) calculated in step S111 ( S112 ).

[0102] Then, after step S112 is completed and a predetermined time has passed since step S110, step S110 is returned to. The temperature detection unit 94 and the second workpiece spindle control unit 87 repeatedly perform steps S110, S111, and S112 while the workpiece W is being cooled. Each time steps S110, S111, and S112 are repeated, the value of m in the above formula is an integer value that increases from 1. As the second workpiece spindle 117 moves in the -Z axis direction, the spindle distance H between the first workpiece spindle 112 and the second workpiece spindle 117 decreases (H3 < H2).

[0103] The method of obtaining the thermal contraction amount ΔV(m) of the workpiece W while taking into account the temperature distribution of the workpiece W in the Z-axis direction is the same as the method of obtaining the thermal expansion amount ΔU(n) of the workpiece W described above.

[0104] Next, once the cooling of the workpiece W is completed, the workpiece W is removed from the first workpiece spindle 112 and the second workpiece spindle 117 (S113). Figure 1 and Figure 2 The method for processing a workpiece of the processing machine 100 is completed.

[0105] According to such a configuration, the interaxial distance between the first holding portion 51 and the second holding portion 52 holding the workpiece W can be freely adjusted using the first workpiece spindle 112 and the second workpiece spindle 117 disposed opposite to each other in the processing machine 100. Therefore, the workpiece processing method in this embodiment can be realized with a simple configuration.

[0106] Fig. 9 It means Figure 7 A block diagram of a modified example of a control system associated with additional processing of a workpiece. Fig.10 It means execution Figure 8 A flowchart of a modified example of the flow of steps in a method for processing a workpiece.

[0107] Reference Fig. 9 and Fig.10 In this modification, the processing machine 100 does not have Fig. 9 The processing machine 100 includes a motor monitoring unit 97. The motor monitoring unit 97 monitors the state of the second workpiece spindle conveying motor 93. More specifically, the motor monitoring unit 97 detects the motor current (load current value) of the second workpiece spindle conveying motor 93.

[0108] In the present modification, the second workpiece spindle control unit 87 controls the second workpiece spindle transport motor 93 based on the motor current of the second workpiece spindle transport motor 93 detected by the motor monitoring unit 97 .

[0109] The control steps during the additional processing of the workpiece W are described representatively. The additional processing of the workpiece W is started (S201). When the additional processing starts in step S201, the second workpiece spindle control unit 87 controls the second workpiece spindle conveying motor 93 so that the second workpiece spindle 117 starts to move in the +Z axis direction at a predetermined speed (S202).

[0110] Next, the motor monitoring unit 97 detects the motor current of the second workpiece spindle transport motor 93 ( S203 ). The motor monitoring unit 97 outputs the detected motor current of the second workpiece spindle transport motor 93 to the second workpiece spindle control unit 87 .

[0111] Next, the second workpiece spindle control unit 87 determines whether the motor current value detected by the motor monitoring unit 97 is constant (S204). If it is determined in step S204 that the motor current value detected by the motor monitoring unit 97 is constant, the process returns to step S203.

[0112] When it is determined that the motor current value detected by the motor monitoring unit 97 in step S204 is not constant, the second workpiece spindle control unit 87 controls the second workpiece spindle conveying motor 93 so as to change the moving speed in the +Z-axis direction of the second workpiece spindle 117 (S205). The motor monitoring unit 97 and the second workpiece spindle control unit 87 repeatedly perform steps S203 to S205 during the additional processing of the workpiece W started in step S201, thereby maintaining the motor current of the second workpiece spindle conveying motor 93 constant. In this case, the load on the second workpiece spindle conveying motor 93 is constant, so the second workpiece spindle 117 moves in the +Z-axis direction according to the extension of the workpiece W in the Z-axis direction.

[0113] Finally, the tool spindle control unit 84 and the additional processing control unit 85 complete the additional processing of the workpiece W. The second workpiece spindle control unit 87 controls the second workpiece spindle transport motor 93 to stop the movement of the second workpiece spindle 117 in the +Z axis direction.

[0114] Fig.11 1 is a perspective view showing an example of a workpiece to be subjected to additional processing. Fig.11 The workpiece processing method in this embodiment can be applied to the maintenance of the turbine blade 500.

[0115] The turbine blade 500 has a leading edge 510 , a trailing edge 520 , an airfoil 540 , and a pair of turbine side faces 530 .

[0116] The leading edge 510 is an edge-shaped blade front end portion where fluid such as air flows in when the turbine blade 500 rotates. The trailing edge 520 is an edge-shaped blade rear end portion where fluid flows out when the turbine blade 500 rotates.

[0117] The airfoil 540 extends between the leading edge 510 and the trailing edge 520. The airfoil 540 extends while being curved between the leading edge 510 and the trailing edge 520. When the turbine blade 500 rotates, the fluid flowing in through the leading edge 510 flows on the airfoil 540 toward the trailing edge 520. The airfoil 540 has a positive pressure surface 540P and a negative pressure surface 540N. A relatively large pressure due to the fluid flowing on the airfoil 540 acts on the positive pressure surface 540P, and a relatively small pressure due to the fluid flowing on the airfoil 540 acts on the negative pressure surface 540N.

[0118] The pair of turbine side surfaces 530 are respectively disposed at both ends of the airfoil 540. The turbine side surfaces 530 are formed of planes. The turbine side surfaces 530 are formed of planes that are perpendicular to the extending directions of the leading edge 510 and the trailing edge 520.

[0119] The turbine blade 500 is formed of a metal material such as a nickel-based alloy or Ti-6Al-4V.

[0120] As the number of times the turbine blade 500 is used increases, a defect may occur at the leading edge 510 or the trailing edge 520, or a relatively small crack or a relatively large pit may occur at the airfoil 540. The turbine blade 500 having such a defect or the like is repaired.

[0121] More specifically, for Figure 1 and Figure 2 In the processing machine 100 shown in the figure, the leading edge 510, the trailing edge 520 and the wing surface 540 are arranged radially outwardly toward the center axis 201, and the turbine blade 500 is held by the first workpiece spindle 112 and the second workpiece spindle 117 in such a manner that the turbine side surface 530 is arranged axially toward the center axis 201.

[0122] Next, by rotating the first workpiece spindle 112 and the second workpiece spindle 117 around the central axis 201, the leading edge 510, the trailing edge 520 or the airfoil 540 to be repaired is arranged opposite to the tool spindle 121. The tool spindle 121 is used to remove the cracked portion of the repaired portion of the turbine blade 500 or to trim the surface into a shape suitable for additional processing.

[0123] Next, the turbine blade 500 is subjected to additional processing. The additional processing head 21 is mounted on the tool spindle 121, and additional processing is performed using the same material powder as the metal material constituting the turbine blade 500, thereby increasing the thickness of the repaired portion of the turbine blade 500. Figure 8 or Fig.10 The flowchart in controls the interaxial distance between the first workpiece spindle 112 and the second workpiece spindle 117 during additional processing.

[0124] Next, cutting after additional processing is performed on the turbine blade 500. The additional processing head 21 is removed from the tool spindle 121, and the thickened portion added to the turbine blade 500 is cut by the tool spindle 121, so that the surface of the turbine blade 500 is finished.

[0125] As another example, the workpiece processing method of the present embodiment can also be applied to the production of a die-cutting roll used for processing films, nonwoven fabrics, and the like.

[0126] If the above-described workpiece processing method and the structure of the processing machine 100 in the embodiment of the present invention are summarized, the workpiece processing method in this embodiment includes: a step of holding the workpiece W using the first holding part 51 and the second holding part 52 that are separately arranged from each other; a step of performing additional processing on the workpiece W by supplying material powder P to the workpiece W held by the first holding part 51 and the second holding part 52 and irradiating the workpiece W with laser L; and a step of moving the first holding part 51 and the second holding part 52 relative to each other in directions away from each other during at least a part of the step of performing additional processing on the workpiece W.

[0127] The processing machine 100 in this embodiment is a processing machine for performing additional processing of a workpiece. The processing machine includes: an additional processing head 21, which supplies material powder P to the workpiece W and irradiates the workpiece W with a laser L; a first workpiece spindle 112, which is used to rotate the workpiece W around a central axis 201 as a predetermined axis; a second workpiece spindle 117, which is arranged opposite to the first workpiece spindle 112 in the axial direction of the central axis 201 and can slide in the axial direction of the central axis 201, and is used to rotate the workpiece W around the central axis 201 as the predetermined axis; and a control device 81, which controls the processing machine 100. The control device 81 controls the movement of the additional processing head 21 so as to supply material powder P to the workpiece W held by the first workpiece spindle 112 and the second workpiece spindle 117, and irradiate the laser L to perform additional processing on the workpiece W, and controls the sliding movement of the second workpiece spindle 117 so as to move the second workpiece spindle 117 away from the first workpiece spindle 112 during at least a portion of the period when the additional processing of the workpiece W is performed.

[0128] According to the workpiece processing method and the processing machine 100 in the embodiment of the present invention configured in this way, it is possible to maintain high processing accuracy of the workpiece in the additional processing of the workpiece using the directional energy deposition method.

[0129] The embodiments disclosed this time should be considered in all points as illustrative and non-restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0130] Industrial Applicability

[0131] The present invention is applicable to additional processing of a workpiece by a directed energy deposition method.

[0132] Description of Reference Numerals

[0133] 21. Additional processing head; 24. Pipeline body; 26. Nozzle; 51. First holding part; 52. Second holding part; 70. Powder feeder; 71. Mixing part; 72. Powder hopper; 76. Laser oscillator; 81. Control device; 82. Program storage part; 83. Program execution part; 84. Tool spindle control part; 85. Additional processing control part; 86. First workpiece spindle control part; 87. Second workpiece spindle control part; 89. Tool spindle conveying motor; 90. Tool spindle rotation motor; 91. First workpiece spindle rotation motor; 92. Second workpiece spindle rotation motor; 93. Second workpiece spindle conveying motor; 94. Temperature detection part; 95. Operation part; 96. Storage part; 97. Motor monitoring part; 100. Processing machine machine; 111, the first spindle stage; 112, the first workpiece spindle; 112f, 117f, 123, the spindle end face; 113, 118, chuck; 116, the second spindle stage; 117, the second workpiece spindle; 121, the tool spindle; 131, the tool holder; 132, the rotating part; 136, the base; 200, the processing area; 201, 201A, 201B, 203, 206, the central axis; 204, the rotation central axis; 205, the splash guard; 500, the turbine blade; 510, the leading edge; 520, the trailing edge; 530, the turbine side; 540, the airfoil; 540N, the negative pressure surface; 540P, the positive pressure surface; H, the distance between the spindles; L, the laser; P, the material powder; T, the temperature; W, the workpiece; fa, the surface.

Claims

1. A method for processing a workpiece, comprising: a step of holding the workpiece by using a first holding portion and a second holding portion that are disposed separately from each other; a step of supplying material powder to the workpiece held by the first holding portion and the second holding portion and irradiating the workpiece with laser light to perform additional processing on the workpiece; and A step of relatively moving the first holding portion and the second holding portion in directions away from each other during at least a portion of a step of performing additional processing on the workpiece.

2. The method for processing a workpiece according to claim 1, wherein: The first holding portion is a first workpiece spindle for rotating the workpiece around a predetermined axis. The second holding portion is a second workpiece spindle that is arranged opposite to the first workpiece spindle in the axial direction of the predetermined axis and can slide in the axial direction of the predetermined axis to rotate the workpiece around the predetermined axis. The step of relatively moving the first holding portion and the second holding portion includes the step of sliding the second workpiece spindle in the axial direction of the predetermined axis.

3. The workpiece processing method according to claim 1 or 2, wherein: The workpiece processing method further comprises: the step of detecting the temperature of the workpiece during at least a portion of the step of additionally processing the workpiece; and a step of calculating the thermal expansion amount of the workpiece based on the detected temperature of the workpiece, The step of relatively moving the first holding portion and the second holding portion includes relatively moving the first holding portion and the second holding portion in directions away from each other by a distance corresponding to the calculated amount of thermal expansion of the workpiece.

4. The workpiece processing method according to any one of claims 1 to 3, wherein: The workpiece processing method further comprises, after the step of performing additional processing on the workpiece, the step of cooling the workpiece while relatively moving the first holding portion and the second holding portion in a direction in which the first holding portion approaches each other.

5. A processing machine, which is a processing machine for performing additional processing of a workpiece, wherein: The processing machine has: an additional processing head for supplying material powder to the workpiece and irradiating laser light; A first workpiece spindle, which is used to rotate the workpiece around a predetermined axis; a second workpiece spindle, which is arranged opposite to the first workpiece spindle in the axial direction of the predetermined axis and can slide in the axial direction of the predetermined axis to rotate the workpiece around the predetermined axis; as well as a control device, which controls the processing machine, For the control device, controlling the operation of the additional processing head so as to perform additional processing on the workpiece by supplying material powder to the workpiece held by the first workpiece spindle and the second workpiece spindle and irradiating the workpiece with laser light; The sliding motion of the second workpiece spindle is controlled so that the second workpiece spindle moves in a direction away from the first workpiece spindle during at least a portion of a period of additional processing on the workpiece.

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