Workpiece machining method, machine tool, and program

Abstract

The present invention provides a workpiece machining method comprising: a step for preparing a workpiece having a plate section that includes a base material and a first coating layer covering at least a portion of the base material; and a step for burring the plate section. If the direction from the base material to the first coating layer is defined as a first direction, the step for burring the plate section includes the formation of a through-hole and a flange in a first region of the plate section by moving a rotating burring tool in the first direction while rotating. Before the step for burring the plate section, a step for removing the first coating layer from the first region of the plate section is performed.

Description

Workpiece machining method, machine tool, and program

[0001] The present invention relates to a workpiece machining method, a machine tool, and a program.

[0002] Burring is a known process for forming through holes and flanges in thin plate materials to ensure sufficient threads when cutting screws or to enable pins or pipes to be fitted into thin plate materials.

[0003] As a related technique, Patent Document 1 discloses a drilling tool. The drilling tool described in Patent Document 1 is used to form a hole and a boss in a metal plate or a metal pipe wall. More specifically, the drilling tool is pressed against the metal plate or metal pipe wall while rotating at high speed. The metal is melted by frictional heat acting between the drilling tool and the metal plate or metal pipe wall, and frictional pressure acting from the drilling tool on the metal plate or metal pipe wall. As the metal melts, a hole is formed and a boss is formed at the same time.

[0004] Publication No. 5-6007

[0005] An object of the present invention is to provide a workpiece processing method, a machine tool, and a program that enable good formation of through holes and flanges in plate material having a coating layer, such as a plating layer plated with pure zinc or a zinc alloy.

[0006] In some embodiments, a method for machining a workpiece includes preparing a workpiece having a plate portion including a base material and a first coating layer covering at least a portion of the base material, and burring the plate portion. When a direction from the base material toward the first coating layer is defined as a first direction, the burring process includes forming a through hole and a flange in a first region of the plate portion by moving a rotating burring tool in the first direction. Prior to the burring process, a step of removing the first coating layer from the first region of the plate portion is performed.

[0007] In some embodiments, the machine tool includes a workpiece support device that supports a workpiece having a plate portion including a base material and a first coating layer covering at least a portion of the base material, a machining head that rotatably supports a burring tool about a rotation axis, a rotation drive device that rotates the burring tool about the rotation axis, a movement device that moves the machining head relative to the workpiece support device, a removal device that removes a portion of the first coating layer from the workpiece, and a control device that controls the rotation drive device, the movement device, and the removal device. The control device is capable of executing a removal mode that removes the first coating layer from a first region of the plate portion by sending a control command to at least the removal device, and a burring processing mode that burrs the plate portion by sending a control command to at least the rotation drive device and the movement device. When the direction from the base material toward the first coating layer is defined as a first direction, the burring processing mode is a mode in which the burring tool that rotates and moves in the first direction forms a through hole and a flange in the first region from which the first coating layer has been removed.

[0008] In some embodiments, the program causes a machine tool to execute a workpiece machining method, the method including: removing the first coating layer from a first region of the plate portion, the first coating layer covering at least a portion of the base material, while the workpiece is supported by a workpiece support device. When a direction from the base material toward the first coating layer is defined as a first direction, the step of burring the plate portion includes forming a through hole and a flange in the first region of the plate portion by moving a rotating burring tool in the first direction.

[0009] The present invention provides a workpiece processing method, machine tool, and program that enable good formation of through holes and flanges in plate material having a coating layer, such as a plating layer plated with pure zinc or a zinc alloy.

[0010] FIG. 1 is a schematic cross-sectional view showing an example of a workpiece prepared in a preparation step. FIG. 2 is a schematic cross-sectional view showing a state in which a removal step of removing a first coating layer from a first region of a plate portion is being performed. FIG. 3 is a schematic cross-sectional view showing an example of a workpiece after the first coating layer has been removed from the first region of the plate portion. FIG. 4 is a schematic cross-sectional view showing a state in which a burring tool moves toward the first region of the plate portion. FIG. 5 is a schematic cross-sectional view showing a state in which a burring process is being performed on the first region of the plate portion. FIG. 6 is a schematic cross-sectional view showing a state in which a tapping tool moves toward a through hole. FIG. 7 is a schematic cross-sectional view showing a state in which a female thread is formed on the wall surface of a through hole. FIG. 8 is a schematic cross-sectional view showing a state after a female thread has been formed on the wall surface of a through hole. FIG. 9 is a schematic cross-sectional view showing a state in which a flange is finely cracked in a comparative example. FIG. 10 is a schematic perspective view showing an example of a workpiece. FIG. 11 is a schematic perspective view showing an example of a workpiece. FIG. 12 is a schematic perspective view showing an example of a workpiece. FIG. 13 is a schematic cross-sectional view showing a state in which a removal step of removing a first coating layer from a first region of a plate portion is being performed. FIG. 14 is a schematic cross-sectional view showing a state in which a removal step is being performed using a chemical solution. FIG. 15 is a schematic cross-sectional view showing a state in which a removal step is being performed using a second tool. FIG. 16 is a schematic perspective view showing an example of a burring tool. FIG. 17 is a diagram showing a machine tool according to the first embodiment. FIG. 18 is a schematic cross-sectional view showing a state in which a second wall, which is an obstacle, is present between a laser head and the first region of the plate portion. FIG. 19 is a diagram showing a machine tool according to the first embodiment. FIG. 20 is a diagram showing a machine tool according to the first embodiment. FIG. 21 is a diagram showing an example of a tool changer. FIG. 22 is a diagram showing a machine tool according to the first embodiment. FIG. 23 is a flowchart showing an example of a workpiece machining method according to an embodiment. Fig. 24 is a diagram schematically showing a part of a machine tool in a second embodiment. Fig. 25 is a diagram showing an enlarged part of Fig. 24. Fig. 26 is a diagram schematically showing a machine tool in a second embodiment.Fig. 27 is a diagram schematically showing a machine tool in a second embodiment. Fig. 28 is a diagram schematically showing a part of a machine tool in a second embodiment. Fig. 29 is a diagram schematically showing a part of a machine tool in a second embodiment. Fig. 30 is a diagram schematically showing an example of a storage medium on which a program is recorded.

[0011] Hereinafter, a workpiece machining method, a machine tool 1, and a program 822 according to an embodiment will be described with reference to the drawings. In the following description of the embodiment, parts and components having the same functions are denoted by the same reference numerals, and repeated description of parts and components denoted by the same reference numerals will be omitted.

[0012] First Embodiment A workpiece machining method and a machine tool 1A according to a first embodiment will be described with reference to FIGS. 1 to 23 . FIG. 1 is a schematic cross-sectional view illustrating an example of a workpiece 9 prepared in a preparation step. FIG. 2 is a schematic cross-sectional view illustrating a removal step of removing the first coating layer 93 from the first region RG1 of the plate portion 90. FIG. 3 is a schematic cross-sectional view illustrating an example of the workpiece 9 after the first coating layer 93 has been removed from the first region RG1 of the plate portion 90. FIG. 4 is a schematic cross-sectional view illustrating a burring tool 10 moving toward the first region RG1 of the plate portion 90. FIG. 5 is a schematic cross-sectional view illustrating a burring process being performed on the first region RG1 of the plate portion 90. FIG. 6 is a schematic cross-sectional view illustrating a tap tool 18 moving toward a through hole 96. FIG. 7 is a schematic cross-sectional view illustrating a female thread 96s being formed on the wall surface of the through hole 96. FIG. 8 is a schematic cross-sectional view showing a state after a female thread 96s is formed on the wall surface of the through hole 96. FIG. 9 is a schematic cross-sectional view showing a state in which the flange 97 is finely cracked in a comparative example. FIG. 10 is a schematic perspective view showing an example of the workpiece 9. FIG. 11 is a schematic perspective view showing an example of the workpiece 9. FIG. 12 is a schematic perspective view showing an example of the workpiece 9. FIG. 13 is a schematic cross-sectional view showing a state in which a removal step is performed to remove the first coating layer 93 from the first region RG1 of the plate portion 90. FIG. 14 is a schematic cross-sectional view showing a state in which the removal step is performed using the chemical liquid L. FIG. 15 is a schematic cross-sectional view showing a state in which the removal step is performed using the second tool T2. FIG. 16 is a schematic perspective view showing an example of the burring tool 10. FIG. 17 is a diagram showing a machine tool 1A according to the first embodiment. Fig. 18 is a schematic cross-sectional view showing a state in which a second wall 99b, which is an obstacle, is present between the laser head 51 and the first region RG1 of the plate portion 90. Figs. 19 and 20 are diagrams showing a machine tool 1A in the first embodiment. Fig. 21 is a diagram showing a diagram showing an example of a tool changer 6. Fig. 22 is a diagram showing a diagram showing a machine tool 1A in the first embodiment. Fig. 23 is a flowchart showing an example of a workpiece machining method in an embodiment.

[0013] As illustrated in FIG. 1 , in a first step ST1, a workpiece 9 is prepared. The first step ST1 is a preparation process. The workpiece 9 prepared in the preparation process has a plate portion 90. In the example illustrated in FIG. 1 , the plate portion 90 is configured by a first wall 99a. The workpiece 9 may have a second wall 99b in addition to the first wall 99a. In the example illustrated in FIG. 1 , the second wall 99b is arranged opposite the first wall 99a. The workpiece 9 may have a third wall 99c in addition to the first wall 99a and the second wall 99b. In the example illustrated in FIG. 1 , the third wall 99c connects the first wall 99a and the second wall 99b. The workpiece 9 may have a fourth wall 99d (see FIG. 10 if necessary) arranged opposite the third wall 99c.

[0014] In the example shown in FIG. 1 , the plate portion 90 of the workpiece 9 includes a base material 91 and a first coating layer 93 that covers at least a portion of the base material 91 .

[0015] As illustrated in Fig. 2, in the second step ST2, the first coating layer 93 is removed from the first region RG1 of the plate portion 90. The second step ST2 is a removing step. Fig. 3 shows the workpiece 9 after the removing step has been performed.

[0016] 4, in a third step ST3, the relative position of the workpiece 9 with respect to the burring tool 10 is changed so that the burring tool 10 faces the first region RG1 of the workpiece 9. The third step ST3 is a position changing step.

[0017] As illustrated in FIG. 4, in this specification, the direction from the base material 91 toward the first coating layer 93 is defined as a first direction DR1, and the direction opposite to the first direction DR1 is defined as a second direction DR2.

[0018] After the position change step (third step ST3) is performed, the first direction DR1 coincides with the direction from the burring tool 10 toward the first region RG1 of the workpiece 9.

[0019] As illustrated in Figures 4 and 5, in a fourth step ST4, the plate portion 90 is burred. The fourth step ST4 is a process of burring the plate portion 90 (hereinafter referred to as the "burring process"). Note that "burring" refers to a process of stretching the edge of a hole into a cylindrical shape. As illustrated in Figure 5, by burring the plate portion 90, the edge of the hole is stretched into a cylindrical shape, and as a result, a flange 97 is formed.

[0020] In the example shown in Figures 4 and 5, the burring process (fourth step ST4) includes forming a through hole 96 and a flange 97 in the first region RG1 of the plate portion 90 by moving the rotating burring tool 10 in the first direction DR1.

[0021] As illustrated in Fig. 9 , it is assumed that the burring process is performed without removing the first coating layer 93 from the first region RG1 of the plate portion 90. In this case, the flange 97 may not be formed well due to the presence of the first coating layer 93 (e.g., due to the presence of the first coating layer 93 containing zinc). For example, as illustrated in Fig. 9 , the flange 97 may crack into small pieces due to the presence of the first coating layer 93.

[0022] In contrast, in the first embodiment, a step of removing the first coating layer 93 from the first region RG1 of the plate portion 90 is performed before the burring step (see FIG. 2). Therefore, regardless of the material of the first coating layer 93, the presence of the first coating layer 93 does not cause poor formation of the flange 97 during the burring step. For example, the presence of the first coating layer 93 does not hinder the generation or transmission of frictional heat by the rotating burring tool 10 in the first region RG1. In other words, frictional heat generated between the burring tool 10 and the plate portion 90 is effectively transmitted to the entire first region RG1, and the through hole 96 and the flange 97 are successfully formed in the first region RG1 (see FIG. 5).

[0023] (Optional Additional Configuration) Next, with reference to FIGS. 1 to 23, an optional additional configuration that can be employed in the workpiece machining method and machine tool 1A in the first embodiment will be described.

[0024] (First coating layer 93) As illustrated in Figure 4, the first coating layer 93 is a coating layer arranged on the surface of the first region RG1 of the plate portion 90 opposite to the surface that will come into contact with the burring tool 10.

[0025] The first coating layer 93 is, for example, a plating layer 93a that covers at least a portion of the base material 91. More specifically, the first coating layer 93 is, for example, a plating layer 93a of pure zinc or a zinc alloy (in other words, the first coating layer 93 is a plating layer 93a formed by plating at least a portion of the base material 91 with pure zinc or a zinc alloy). The plating layer 93a may be formed by any method. For example, the plating layer 93a may be formed on the base material 91 by electroforming, electroless plating, hot-dip plating, or vacuum plating (e.g., vacuum deposition).

[0026] Alternatively, or additionally, the first coating layer 93 may be a color coating layer and / or a corrosion protection layer.

[0027] Conventionally, when a base material covered with a first coating layer containing zinc is subjected to burring using a method that uses frictional heat, a flange cannot be formed satisfactorily (see FIG. 9 ). In contrast, in the first embodiment, the first coating layer 93 is removed in the first region RG1, so that the through hole 96 and the flange 97 can be formed satisfactorily in the first region RG1 regardless of the material of the first coating layer 93.

[0028] 10 , the first coating layer 93 faces an internal region SP of the workpiece 9 (more specifically, a hollow portion defined by the workpiece 9). More specifically, in the example shown in Fig. 10 , the workpiece 9 is a pipe 9a, and the first coating layer 93 faces an internal space SP1 of the pipe 9a.

[0029] Alternatively, as illustrated in Fig. 11, the cross section perpendicular to the longitudinal direction of the workpiece 9 may have a C-shape. In the example illustrated in Fig. 11, the first coating layer 93 also faces the internal region SP of the workpiece 9 (more specifically, the substantial cavity defined by the workpiece 9).

[0030] 10 and 11 , when the first coating layer 93 is an inner surface coating layer that coats the inner surface of the base material 91, it is preferable that an access opening OP is formed in the workpiece 9 to allow a means for removing the first coating layer 93 to access the first region RG1. The access opening OP may be formed in advance prior to the execution of the removal step (second step ST2), or may be formed in the workpiece 9 at the timing when the removal step (second step ST2) is executed. The access opening OP may be a through-hole type opening OP1 as illustrated in FIG. 10 , or a slit type opening OP2 as illustrated in FIG. 11 .

[0031] In the example shown in Fig. 2, the means for removing the first coating layer 93 includes a laser B. As exemplified in Fig. 13, the means for removing the first coating layer 93 may include, in addition to the laser B, an assist gas G supplied toward the workpiece 9. The assist gas G has a function of removing the molten material melted by the laser B from the area to be irradiated with the laser B. The assist gas G may be air, oxygen, or an inert gas such as nitrogen or argon.

[0032] 14 , the means for removing the first coating layer 93 may include a chemical solution L (e.g., an organic solution) for removing the first coating layer 93. In the example shown in FIG. 14 , the chemical solution L is applied to the first coating layer 93, thereby removing the first coating layer 93 from the first region RG1 of the plate portion 90.

[0033] 15 , the means for removing the first coating layer 93 may include a tool (e.g., a cutting tool, a file, etc.) for removing the first coating layer 93. Hereinafter, the tool for removing the first coating layer 93 will be referred to as a second tool T2. In the example shown in FIG. 15 , the first coating layer 93 is removed from the first region RG1 of the plate portion 90 by the second tool T2 coming into contact with the first coating layer 93.

[0034] In the example shown in FIGS. 10 and 11 , the workpiece 9 has a first wall 99a in which a first region RG1 to be burred (the region surrounded by a dashed line in FIGS. 10 and 11 is the first region RG1) is located, and a second wall 99b disposed opposite the first wall 99a. An access opening OP is also formed in the second wall 99b. In the example shown in FIGS. 10 and 11 , the access opening OP is disposed opposite the first region RG1 (more specifically, the removal target region RT described below). Therefore, a means for removing the first coating layer 93 (e.g., a laser B for removing the first coating layer 93, a chemical solution L for removing the first coating layer 93, a tool T1 for applying the chemical solution L for removing the first coating layer 93, or a second tool T2 for removing the first coating layer 93) can easily approach the first coating layer 93 through the access opening OP.

[0035] In the example shown in FIG. 3, the first coating layer 93 is removed from the first region RG1 of the plate portion 90, so that an exposed surface 91s is formed in the first region RG1, where the base material 91 is substantially exposed.

[0036] In this specification, the portion of the region occupied by the first coating layer 93 that will be removed by the above-mentioned removal step (or by the removal device 5 described below) is defined as a removal target region RT (see FIGS. 1 and 2). The above-mentioned first direction DR1 coincides with the direction from the portion of the base material 91 that contacts the removal target region RT toward the removal target region RT.

[0037] In this specification, the region formed by removing the first coating layer 93 is defined as the removed region RB (see FIG. 3). In other words, the removal target region RT becomes the removed region RB by performing the removal process (second step ST2). The first direction DR1 described above coincides with the direction from the exposed surface 91s toward the removed region RB.

[0038] The size of the access opening OP may be set according to the size of the removal target region RT or the size of the through hole 96 formed in the first region RG1 in the burring process. For example, the larger the size of the removal target region RT or the size of the through hole 96, the larger the size of the access opening OP may be.

[0039] 3, the size of the access opening OP (more specifically, the opening area of ​​the access opening OP) is smaller than the size of the removed region RB (more specifically, the area of ​​the removed region RB). The small size of the access opening OP suppresses a decrease in strength of the workpiece 9 due to the presence of the access opening OP. Alternatively, the size of the access opening OP may be equal to or larger than the size of the removed region RB.

[0040] In the example shown in Figure 6, the inner diameter of the access opening OP is larger than the inner diameter of the through hole 96. Alternatively, the inner diameter of the access opening OP may be equal to or smaller than the inner diameter of the through hole 96. In the example shown in Figure 6, the through hole 96 is positioned opposite the access opening OP.

[0041] 1 , the plate portion 90 of the workpiece 9 is disposed on the second direction DR2 side of the base material 91 and includes a second coating layer 94 that covers at least a portion of the base material 91. In the example shown in FIG. 1 , the workpiece 9 prepared in the preparation process (first step ST1) includes the base material 91, the first coating layer 93, and the second coating layer 94. The base material 91 is sandwiched between the first coating layer 93 and the second coating layer 94.

[0042] The material of the second coating layer 94 may be the same as the material of the first coating layer 93 or may be different from the material of the first coating layer 93 .

[0043] The second coating layer 94 is, for example, a plating layer 94a that covers at least a portion of the base material 91. The plating layer 94a may be formed by any method. For example, the plating layer 94a may be formed on the base material 91 by electroforming, electroless plating, hot-dip plating, or vacuum plating (e.g., vacuum deposition).

[0044] Alternatively, or in addition, the second coating layer 94 may be a color coating layer and / or a corrosion protection layer. The second coating layer 94 may be a coating layer containing elemental zinc. For example, the second coating layer 94 may be a plating layer of pure zinc or a zinc alloy.

[0045] In the example shown in FIGS. 10 and 11, the second coating layer 94 is an outer surface coating layer that coats the outer surface of the base material 91.

[0046] 2 and 3 , the second coating layer 94 is not subject to removal in the removal process (second step ST2). In other words, the second coating layer 94 is not removed by performing the removal process (second step ST2) and remains as is. Alternatively, the removal process (second step ST2) may remove both the first coating layer 93 and the second coating layer 94 from the first region RG1 of the plate portion 90. The removal of the first coating layer 93 and the second coating layer 94 from the first region RG1 of the plate portion 90 may be performed by laser irradiation, by using a chemical solution, or by using a tool such as a cutting tool (in other words, the second tool T2).

[0047] (Base Material 91) The base material 91 is made of a metal such as iron or stainless steel. The base material 91 has a sufficient thickness to enable the flange 97 to be formed. In the example shown in FIG. 1 , the thickness of the base material 91 is greater than the thickness of the first coating layer 93 and greater than the thickness of the second coating layer 94.

[0048] (Workpiece 9) The workpiece 9 may be a pipe as illustrated in Fig. 10 or an angle bar as illustrated in Fig. 12. The workpiece 9 may also be a channel material or a flat plate. The workpiece 9 may also be a long workpiece extending in a direction perpendicular to the first direction DR1.

[0049] The workpiece 9 may be a part that defines a flow path through which a fluid flows, a part for heating and cooling equipment, a part for home appliances, an automobile part, a part for a control panel, a building part, a part for a shelf, a part for furniture, a part for agricultural machinery, a part for kitchen equipment, or a part for logistics equipment.

[0050] The thickness TH (see FIG. 1) of the plate portion 90 in the first region RG1 is, for example, not less than 0.5 mm and not more than 6 mm.

[0051] 2 , the step of removing the first coating layer 93 (removal step: second step ST2) includes irradiating the first coating layer 93 with a laser B to remove the first coating layer 93 from the first region RG1 of the plate portion 90. In the example shown in FIG. 2 , in the removal step, the traveling direction of the laser B toward the first coating layer 93 is the second direction DR2 (in other words, the direction opposite to the direction from the base material 91 toward the first coating layer 93).

[0052] 2, an access opening OP (more specifically, an access through-hole) may be formed in the second wall 99b of the workpiece 9 by the laser B emitted from the laser head 51. In the example shown in FIG. 2, the laser B emitted from the laser head 51 passes through the access opening OP formed in the second wall 99b of the workpiece 9. Furthermore, the laser B passing through the access opening OP is irradiated onto the first wall 99a of the workpiece 9, thereby removing the first coating layer 93 from a portion of the first wall 99a.

[0053] Alternatively, or additionally, as illustrated in FIG. 14, the removal process (second step ST2) for removing the first coating layer 93 may include removing the first coating layer 93 from the first region RG1 of the plate portion 90 by applying a chemical solution L to the first coating layer 93.

[0054] 14 , the chemical liquid L is supplied across the access opening OP formed in the second wall 99 b of the workpiece 9. Furthermore, the chemical liquid L supplied across the access opening OP is applied to the first wall 99 a of the workpiece 9, thereby removing the first coating layer 93 from a portion of the first wall 99 a.

[0055] Alternatively, or additionally, as illustrated in FIG. 15 , the removal process (second step ST2) for removing the first coating layer 93 may include removing the first coating layer 93 from the first region RG1 of the plate portion 90 by contacting a second tool T2, such as a cutting tool, with the first coating layer 93.

[0056] 15 , a second tool T2 such as a cutting tool is inserted into an access opening OP formed in the second wall 99 b of the workpiece 9. Furthermore, the second tool T2 inserted into the access opening OP removes the first coating layer 93 from a portion of the first wall 99 a of the workpiece 9.

[0057] 3 and 4 , after the first coating layer 93 is removed from the first region RG1 of the plate portion 90, the relative position of the workpiece 9 with respect to the burring tool 10 is changed so that the burring tool 10 faces the first region RG1 of the workpiece 9 before the step of burring the plate portion 90 (burring step: fourth step ST4) is performed (hereinafter referred to as the "position changing step"). As exemplified in FIGS. 3 and 4 , the position changing step may include flipping the workpiece 9. More specifically, the position changing step may include rotating the workpiece 9 by 180 degrees around an axis AT parallel to the longitudinal direction of the workpiece 9.

[0058] (Burring process) The process of burring the plate portion 90 (burring process: fourth step ST4) includes transmitting frictional heat generated between the rotating burring tool 10 and the plate portion 90 to the first region RG1 of the plate portion 90, and pressing the first region RG1 of the plate portion 90 in the first direction DR1 by the rotating burring tool 10.

[0059] Frictional heat generated between the rotating burring tool 10 and the plate portion 90 is transferred to the first region RG1 of the plate portion 90, softening (more specifically, plasticizing) the first region RG1. In the first embodiment, before the step of burring the plate portion 90 (burring step: fourth step ST4) is performed, the first coating layer 93 covering the surface of the base material 91 on the first direction DR1 side is removed from the first region RG1 (see FIGS. 2 and 3 ). Therefore, during the burring step, frictional heat is transferred well throughout the entire first region RG1, and the presence of the first coating layer 93 does not impede the transfer of frictional heat.

[0060] As illustrated in FIG. 5 , in the step of burring the plate portion 90 (burring step: fourth step ST4), the first region RG1 softened by frictional heat is pressed in the first direction DR1 by the burring tool 10. Furthermore, by pressing the first region RG1 softened by frictional heat in the first direction DR1 by the burring tool 10, a through hole 96 is formed in the first region RG1, and the edge of the through hole 96 is stretched into a cylindrical shape in the first direction DR1. In this way, a flange 97 is formed in the first region RG1. In the example illustrated in FIG. 5 , in the step of burring the plate portion 90, the formation of the through hole 96 and the formation of the flange 97 are performed simultaneously.

[0061] In this specification, forming the through hole 96 in the first region RG1 includes forming the through hole 96 through which the burring tool 10 passes in the first region RG1 in which no pilot hole is provided (see FIGS. 4 and 5 ). In addition, in this specification, forming the through hole 96 in the first region RG1 includes forming the through hole 96 through which the burring tool 10 passes in the first region RG1 by expanding a pilot hole that is previously provided in the first region RG1. In other words, a pilot hole may or may not be provided in the first region RG1 before the step of burring the plate portion 90 (burring step: fourth step ST4) is performed.

[0062] 4 and 5 , the step of burring the plate portion 90 (burring step: fourth step ST4) may include moving the rotating burring tool 10 in the first direction DR1 so that the rotating burring tool 10 crosses the second coating layer 94 and the base material 91 in this order. In the example shown in FIGS. 4 and 5 , the second coating layer 94 is not removed from the first region RG1 before the burring step is performed, and the second coating layer 94 remains as is. By omitting the step of removing the second coating layer 94 from the first region RG1, the total time required to process the workpiece is shortened.

[0063] 4 , the burring tool 10 has a tip portion 11 having a tapered shape and a base portion 13 continuing from the tip portion 11. The burring tool 10 may also have a tip portion 11 having a tapered shape, a base portion 13 continuing from the tip portion 11, and a shoulder portion 15 continuing from the base portion 13. In other words, the burring tool 10 may have the tip portion 11 having a tapered shape, a shoulder portion 15, and the base portion 13 arranged between the tip portion 11 and the shoulder portion 15.

[0064] The tip portion 11 and the base portion 13 function to form a through hole 96 and a flange 97 in the first region RG1 of the plate portion 90. More specifically, the tip portion 11 in the rotating state presses the first region RG1 of the plate portion 90 in the first direction DR1, thereby expanding the hole formed in the first region RG1. As a result, the through hole 96 is formed in the first region RG1. Furthermore, the base portion 13 in the rotating state is inserted into the through hole 96 formed in the first region RG1, thereby adjusting the shape of the through hole 96 and the shape of the flange 97. When a cross section perpendicular to the central axis of the burring tool 10 is defined as a transverse section, the size and shape of the transverse section of the base portion 13 may be approximately constant along the central axis of the burring tool 10.

[0065] The cross-sectional shape of the tip portion 11 of the burring tool 10 may be circular, may be a rounded polygonal shape (for example, a rounded rectangle) as exemplified in Fig. 16, or may be another shape. The cross-sectional shape of the base portion 13 of the burring tool 10 may be circular, may be a rounded polygonal shape (for example, a rounded rectangle) as exemplified in Fig. 16, or may be another shape.

[0066] 5 , the shoulder portion 15 has a function of adjusting the shape of the surface on the second direction DR2 side of the plate portion 90 of the workpiece 9. More specifically, the shoulder portion 15 in the rotating state presses the surface on the second direction DR2 side of the plate portion 90, thereby adjusting the shape of the surface.

[0067] (Tool Changing Step) The workpiece machining method in the first embodiment may include a step of changing the burring tool 10 held by the machining head 30 to a tap tool 18 (see FIG. 6 ) (hereinafter referred to as a "tool changing step"). The tool changing step is performed, for example, using a tool changing device. Alternatively, the tool changing step may be performed manually. Furthermore, if the machine tool in the first embodiment includes a second machining head that holds the tap tool 18 in addition to the machining head 30 that holds the burring tool 10, the tool changing step may be omitted.

[0068] 6 and 7 , the workpiece machining method according to the first embodiment may include a step (hereinafter referred to as the “tapping step”) of forming a female thread on a wall surface 96w that defines the through hole 96. The tapping step is performed as a fifth step ST5 after the fourth step ST4 (burring step).

[0069] 6 and 7, the tapping step (fifth step ST5) includes moving the rotating tap tool 18 in the first direction DR1 to form a female thread 96s on the wall surface 96w that defines the through hole 96. Fig. 8 shows the state after the tapping step has been performed.

[0070] In the first embodiment, the flange 97 is well formed in the burring process because the first coating layer 93 is removed from the first region RG1 of the plate portion 90. Furthermore, because the flange 97 is well formed, the female thread 96s can be easily formed on the inner peripheral surface of the flange 97 by performing the tapping process.

[0071] (Machine tool 1A) As illustrated in FIG. 17 , the machine tool 1A in the first embodiment includes a workpiece support device 2, a machining head 30, a rotation drive device 36 (e.g., a motor 36m), a moving device 4, a removal device 5, and a control device 8.

[0072] The workpiece support device 2 supports the workpiece 9. The workpiece support device 2 may have a first chuck 21 that supports a first portion of the workpiece 9 and a second chuck 23 that supports a second portion of the workpiece 9.

[0073] The machining head 30 supports the burring tool 10 rotatably around the rotation axis AX. In the example shown in Fig. 4, the machining head 30 has a rotating body 31 and a frame 33 that rotatably supports the rotating body 31. In the example shown in Fig. 4, the rotating body 31 supports the burring tool 10 via a first tool holder HD1.

[0074] The rotation drive device 36 rotates the burring tool 10 about a rotation axis AX that coincides with the central axis of the burring tool 10. More specifically, the rotation drive device 36 rotates the rotating body 31 about a first axis AX1, thereby rotating the burring tool 10 about the rotation axis AX. In the example shown in Fig. 4, the first axis AX1, which is the rotation axis of the rotating body 31, and the rotation axis AX of the burring tool 10 are coaxial.

[0075] 17 , the moving device 4 moves the machining head 30 relative to the workpiece supporting device 2. The moving device 4 also moves the laser head 51 relative to the workpiece supporting device 2.

[0076] The removal device 5 removes a portion of the first coating layer 93 from the workpiece 9. In the example shown in FIG. 17 , the removal device 5 includes a laser irradiation device 50a having a laser head 51. Alternatively, or additionally, the removal device 5 may include a chemical solution application device 50b (see FIG. 14 ) and / or a cutting device 50c (see FIG. 15 ). As shown in FIG. 15 , when a second tool T2 such as a cutting tool is attached to the processing head 30, the processing head 30 and the second tool T2 function as the removal device 5.

[0077] The control device 8 controls the rotation drive device 36, the moving device 4, and the removing device 5. Additionally, the control device 8 may control the workpiece supporting device 2.

[0078] The control device 8 is capable of executing a removal mode M1. The removal mode M1 is a mode in which the control device 8 transmits a control command to at least the removal device 5, thereby removing the first coating layer 93 from the first region RG1 of the plate portion 90 using at least the removal device 5. More specifically, as illustrated in Fig. 17 , the removal mode M1 includes transmitting an emission command E1 from the control device 8 to the laser irradiation device 50a so that the first coating layer 93 is removed from the first region RG1 of the plate portion 90 by a laser B emitted from the laser head 51.

[0079] For example, as illustrated in FIG. 17 , the control device 8 executing the removal mode M1 transmits a first movement command S1 to the moving device 4 to move the laser head 51 relative to the workpiece support device 2. Upon receiving the first movement command S1, the moving device 4 moves the laser head 51 relative to the workpiece support device 2 so that the first region RG1 of the plate portion 90 is positioned on the laser emission axis of the laser head 51. The control device 8 executing the removal mode M1 also transmits an emission command E1 to the laser irradiation device 50a. Upon receiving the emission command E1, the laser irradiation device 50a emits a laser beam from the laser head 51 in a direction toward the first region RG1 of the plate portion 90. Furthermore, upon receiving the first movement command S1, the moving device 4 moves the laser head 51 relative to the workpiece support device 2 so that the laser beam emitted from the laser head 51 scans the removal target region RT (see the dashed arrow in FIG. 2 ). In this manner, the first coating layer 93 is removed from the first region RG1 of the plate portion 90 by the laser beam B emitted from the laser head 51. It should be noted that if the spot diameter of the laser B irradiated onto the first region RG1 is equal to the size of the region to be removed RT, scanning with the laser B is not necessary.

[0080] As illustrated in Figure 18, if the second wall 99b of the workpiece 9 is present between the laser emission port 52 of the laser head 51 and the first region RG1 of the plate portion 90, when the removal mode M1 is executed by the control device 8, the laser B emitted from the laser head 51 forms an access opening OP (see Figure 2) in the second wall 99b of the workpiece 9, and the laser B emitted from the laser head 51 removes the first coating layer 93 from the first region RG1 of the plate portion 90.

[0081] The control device 8 may be capable of executing an inversion mode M2 ​​in which the workpiece 9 is inverted. The inversion mode M2 ​​is a mode in which the control device 8 sends a control command to the workpiece support device 2, thereby inverting the workpiece 9 using the workpiece support device 2.

[0082] For example, as illustrated in Fig. 19 , the control device 8 executing the inversion mode M2 ​​transmits an inversion command RW to the workpiece supporting device 2 to invert the workpiece 9. The workpiece supporting device 2 that receives the inversion command RW inverts the workpiece 9. More specifically, the workpiece supporting device 2 that receives the inversion command RW rotates the workpiece 9 by 180 degrees around an axis AT that is parallel to the longitudinal direction of the workpiece 9. In the example shown in Fig. 19 , the workpiece 9 is inverted by the workpiece supporting device 2 that receives the inversion command RW rotating the first chuck 21 and the second chuck 23 that support the workpiece 9 by 180 degrees around an axis AT that is parallel to the longitudinal direction of the workpiece 9. Fig. 19 shows the state after the workpiece 9 has been inverted.

[0083] The control device 8 can execute a burring mode M3. The burring mode M3 is a mode in which the plate portion 90 is burred by transmitting a control command from the control device 8 to at least the rotation drive device 36 and the movement device 4. The burring mode M3 is also a mode in which a through hole 96 and a flange 97 are formed in the first region RG1 from which the first coating layer 93 has been removed, using the burring tool 10 that moves in the first direction DR1 in a rotating state.

[0084] For example, as illustrated in FIG. 20 , the control device 8 executing the burring machining mode M3 transmits a second movement command S2 to the movement device 4 to move the burring tool 10 relative to the workpiece support device 2. The movement device 4, upon receiving the second movement command S2, moves the burring tool 10 relative to the workpiece support device 2 so that the first region RG1 of the plate portion 90 is positioned on the rotation axis AX of the burring tool 10. The control device 8 executing the burring machining mode M3 also transmits a first rotation command R1 to the rotation drive device 36. The rotation drive device 36, upon receiving the first rotation command R1, rotates the burring tool 10 about the rotation axis AX. Furthermore, upon receiving the second movement command S2, the movement device 4 moves the rotating burring tool 10 in the first direction DR1 so that the rotating burring tool 10 crosses the first region RG1 of the plate portion 90 (see arrow AR1 in FIG. 4 or FIG. 20 ). In this way, the through hole 96 and the flange 97 are formed in the first region RG1 of the plate portion 90. In the example shown in Fig. 5, the burring mode M3 is executed, whereby the through hole 96 and the flange 97 are simultaneously formed in the first region RG1 of the plate portion 90.

[0085] The control device 8 may be capable of executing a tool change mode M4. The tool change mode M4 is a mode in which the control device 8 sends a control command to at least the movement device 4 and the tool change device 6 (see FIG. 21 ), thereby changing the burring tool 10 attached to the machining head 30 to the tap tool 18 using at least the movement device 4 and the tool change device 6.

[0086] For example, as illustrated in Fig. 21 , the control device 8 executing the tool change mode M4 transmits a movement command S4 to the movement device 4. The movement device 4 receiving the movement command S4 moves the machining head 30 to the tool change position P1 (see Fig. 21 ). The control device 8 executing the tool change mode M4 also transmits a tool change command C1 to the tool change device 6. The tool change device 6 receiving the tool change command C1 replaces the burring tool 10 held by the machining head 30 with a tap tool 18.

[0087] The control device 8 may be capable of executing a tapping mode M5. The tapping mode M5 is a mode in which the control device 8 sends a control command to at least the rotation drive device 36 and the movement device 4, thereby forming a female screw 96s in the wall surface 96w that defines the through hole 96 using at least the rotation drive device 36 and the movement device 4.

[0088] For example, as illustrated in FIG. 22 , the control device 8 executing the tapping mode M5 transmits a third movement command S3 to the movement device 4 to move the tap tool 18 relative to the workpiece support device 2. The movement device 4 receiving the third movement command S3 moves the tap tool 18 relative to the workpiece support device 2 so that the central axis of the through hole 96 is aligned with the rotation axis AX of the tap tool 18. The control device 8 executing the tapping mode M5 also transmits a second rotation command R2 to the rotation drive device 36. The rotation drive device 36 receiving the second rotation command R2 rotates the tap tool 18 around the rotation axis AX. Furthermore, the movement device 4 receiving the third movement command S3 moves the rotating tap tool 18 in the first direction DR1 so that a female thread 96s is formed on the wall surface 96w that defines the through hole 96. In this way, the female thread 96s is formed on the wall surface 96w that defines the through hole 96.

[0089] Second Embodiment A workpiece machining method, machine tool 1B, and program 822 according to a second embodiment will be described with reference to Figures 1 to 30. Figure 24 is a diagram schematically showing a portion of machine tool 1B according to the second embodiment. Figure 25 is a diagram showing an enlarged portion of Figure 24. Figures 26 and 27 are diagrams schematically showing machine tool 1B according to the second embodiment. Figures 28 and 29 are diagrams schematically showing a portion of machine tool 1B according to the second embodiment. Figure 30 is a diagram schematically showing an example of a storage medium 82M on which program 822 is recorded.

[0090] In the second embodiment, differences from the first embodiment will be mainly described. On the other hand, in the second embodiment, repeated descriptions of matters already described in the first embodiment will be omitted. Therefore, it goes without saying that matters already described in the first embodiment can be applied to the second embodiment even if they are not explicitly described in the second embodiment. Conversely, all matters described in the second embodiment can be applied to the first embodiment.

[0091] As illustrated in Figure 24, the machine tool 1B in the second embodiment includes a work support device 2, a machining head 30, a rotation drive device 36, a moving device 4, a removal device 5 (e.g., a laser irradiation device 50a), and a control device 8.

[0092] The work support device 2, processing head 30, rotation drive device 36, moving device 4, removal device 5 (e.g., laser irradiation device 50a), and control device 8 have already been described in the first embodiment, so repeated explanations of these configurations will be omitted.

[0093] The second embodiment has the same effects as the first embodiment.

[0094] The workpiece machining method according to the second embodiment includes a preparation step (first step ST1), a removal step (second step ST2), and a burring step (fourth step ST4). Optionally, the workpiece machining method according to the second embodiment may include a position change step (third step ST3) and / or a tapping step (fifth step ST5).

[0095] The preparation step, removal step, position change step, burring step, and tapping step have already been described in the first embodiment, so repeated description of these steps will be omitted.

[0096] (Optional Additional Configuration) Next, optional additional configurations that can be employed in the second embodiment (or the above-described first embodiment) will be described with reference to FIGS.

[0097] 25 , the workpiece 9 has a plate portion 90, and the plate portion 90 includes a base material 91 and a first coating layer 93 that covers at least a portion of the base material 91. The workpiece 9 has already been described in the first embodiment, and therefore a repeated description of the workpiece 9 will be omitted.

[0098] (Workpiece Supporting Device 2 ) In the example shown in FIG. 26 , the workpiece supporting device 2 has a first chuck 21 that supports a first portion of the workpiece 9 and a second chuck 23 that supports a second portion of the workpiece 9 .

[0099] The first chuck 21 may have a gripping member 211 capable of gripping the workpiece 9. The first chuck 21 may be movable in a direction parallel to the X-axis together with the workpiece 9. In the example shown in Fig. 26, the X-axis is an axis parallel to the extension direction of the workpiece 9 gripped by the first chuck 21.

[0100] The second chuck 23 may have a plurality of guide rollers 231 that sandwich the workpiece 9. The plurality of guide rollers 231 guide the movement of the workpiece 9 (more specifically, a long workpiece) in a direction parallel to the X-axis.

[0101] 26 , the workpiece support device 2 has a second rotation drive device 25 that rotates the workpiece 9 about an axis AT that is parallel to the longitudinal direction of the workpiece. The second rotation drive device 25 may include a first motor 25 a that rotates the second rotating body 22 that supports the first chuck 21 about the axis AT, and a second motor 25 b that rotates the third rotating body 24 that supports the second chuck 23 about the axis AT.

[0102] 24, the moving device 4 moves the machining head 30 relative to the workpiece supporting device 2. The moving device 4 also moves the laser head 51 relative to the workpiece supporting device 2.

[0103] 24 , the moving device 4 includes a first moving device 40 that moves the machining head 30. As illustrated in FIG 26 , the moving device 4 may include a second moving device 46 (more specifically, a motor 46m such as a servo motor) that moves the workpiece 9. In the example illustrated in FIG 26 , the second moving device 46 moves the first chuck 21 in a direction parallel to the X-axis, thereby moving the workpiece 9 gripped by the first chuck 21 in a direction parallel to the X-axis.

[0104] In the example shown in Figure 24, the first moving device 40 has a moving body (41a; 43a) that supports the machining head 30 and a driving device (41b; 43b) that moves the moving body (41a; 43a).

[0105] The first moving device 40 may include a first moving body 41a and a first driving device 41b that moves the first moving body 41a in a direction parallel to the Z axis. In the example shown in FIG. 24 , the first moving body 41a directly or indirectly supports the machining head 30 and is movable together with the machining head 30 in a direction parallel to the Z axis. The first moving body 41a may also directly or indirectly support the laser head 51. The first moving body 41a may also be movable together with the laser head 51 in a direction parallel to the Z axis. The Z axis is an axis perpendicular to the X axis. In the example shown in FIG. 24 , the Z axis is an axis parallel to the vertical direction.

[0106] The first moving device 40 may have a second moving body 43a and a second driving device 43b that moves the second moving body 43a in a direction parallel to the Y axis. In the example shown in FIG. 24 , the second moving body 43a directly or indirectly supports the machining head 30 and is movable together with the machining head 30 in a direction parallel to the Y axis. The second moving body 43a may also directly or indirectly support the laser head 51. The second moving body 43a may also be movable together with the laser head 51 in a direction parallel to the Y axis. The Y axis is an axis perpendicular to both the X axis and the Z axis. In the example shown in FIG. 24 , the Y axis is an axis parallel to a horizontal plane.

[0107] The first moving device 40 may have a third driving device 45b that moves the machining head 30 relative to the laser head 51. In the example shown in Fig. 24, the third driving device 45b moves the machining head 30 relative to the laser head 51 in a direction parallel to the Z axis.

[0108] 24 , the laser irradiation device 50a includes a laser head 51, a laser light source 53, and an optical component 55 (e.g., an optical fiber) that transmits a laser from the laser light source 53 to the laser head 51. The laser head 51 includes a laser emission port 52 that emits a laser.

[0109] (Processing head 30) The processing head 30 supports the burring tool 10 rotatably around the rotation axis AX. The processing head 30 has a rotating body 31 and a frame 33 that rotatably supports the rotating body 31. In the example shown in Fig. 24 , the rotating body 31 supports the burring tool 10 via a first tool holder HD1.

[0110] The rotation drive device 36 rotates the rotating body 31 about the first axis AX1, thereby rotating the burring tool 10 about the rotation axis AX. In the example shown in Fig. 24, the first axis AX1, which is the rotation axis of the rotating body 31, and the rotation axis AX of the burring tool 10 are coaxial.

[0111] In the example shown in Figures 28 and 29, the machining head 30 can selectively hold a first tool holder HD1 (see Figure 28) that holds a burring tool 10 and a second tool holder HD2 (see Figure 29) that holds a tapping tool 18.

[0112] (Tool change device 6) The machine tool 1 may be equipped with a tool change device 6. As illustrated in Fig. 21 , the tool change device 6 is capable of replacing a first tool holder HD1 held by the machining head 30 (more specifically, the rotating body 31 of the machining head 30) with a second tool holder HD2 that holds a tap tool 18. The tool change device 6 is also capable of replacing a second tool holder HD2 held by the machining head 30 (more specifically, the rotating body 31 of the machining head 30) with a first tool holder HD1 that holds a burring tool 10.

[0113] The tool change device 6 may include a tool change arm 61, an arm rotation device 63 that rotates the tool change arm 61, and an arm movement device 65 that linearly moves the tool change arm 61. The arm rotation device 63 rotates the tool change arm 61 about the second axis AX2. The arm movement device 65 moves the tool change arm 61 in a direction parallel to the second axis AX2.

[0114] (Control device 8) The control device 8 controls the rotation drive device 36, the movement device 4 (e.g., the first drive device 41b, the second drive device 43b, the third drive device 45b, the motor 46m that moves the workpiece 9, etc.), and the removal device 5 (e.g., the laser irradiation device 50a). Additionally, the control device 8 may control the second rotation drive device 25 and / or the tool change device 6.

[0115] 24, the control device 8 transmits an emission command E1 to the laser irradiation device 50a, thereby causing the laser head 51 to emit the laser B. More specifically, the control device 8 transmits the emission command E1 to the laser irradiation device 50a, and the laser irradiation device 50a that receives the emission command E1 emits the laser B from the laser head 51 (more specifically, from the laser emission port 52 of the laser head 51).

[0116] 28 or 29, the control device 8 transmits a rotation command R to the rotation drive device 36 (e.g., motor 36m) to rotate the burring tool 10 or the tapping tool 18. More specifically, the control device 8 transmits the rotation command R to the rotation drive device 36, and the rotation drive device 36 that receives the rotation command R rotates the burring tool 10 or the tapping tool 18 around the rotation axis AX.

[0117] 24 or 28, the control device 8 transmits a movement command S to the movement device 4, thereby moving the machining head 30 or the laser head 51 relative to the workpiece support device 2. More specifically, the control device 8 transmits the movement command S to the movement device 4, and the movement device 4, which receives the movement command S, moves the machining head 30 or the laser head 51 relative to the workpiece support device 2.

[0118] 24 , the control device 8 includes a hardware processor 80 (hereinafter simply referred to as the “processor 80”), a memory 82, a communication circuit 84, and an input device 86 (for example, a touch panel display 862). The processor 80, the memory 82, the communication circuit 84, and the input device 86 are connected to one another via a bus 88.

[0119] The memory 82 stores data 826 and a program 822. The program 822 stored in the memory 82 may include a first program 822a for implementing the above-described removal mode M1, and may also include a third program 822c for implementing the above-described burring mode M3. The program 822 may also include a second program 822b for implementing the above-described reversal mode M2, and may also include a fourth program 822d for implementing the above-described tool change mode M4. The program 822 may also include a fifth program 822e for implementing the above-described tapping mode M5.

[0120] The memory 82 is a storage medium that can be read by the processor 80 of the control device 8. The memory 82 may be, for example, a non-volatile or volatile semiconductor memory such as a RAM, a ROM, or a flash memory, or may be a magnetic disk or any other type of memory.

[0121] The data necessary for removing the first coating layer 93 may be input to the control device 8 via the input device 86, may be input to the control device 8 from another computer via the communication circuit 84, or may be calculated or derived by the control device 8. The data necessary for removing the first coating layer 93 (e.g., workpiece data 826a including data indicating the thickness of the first coating layer 93, data 826b indicating the position and size of the removal target region RT, characteristic data 826c of an obstacle between the removal target region RT and the laser head 51, laser output parameters 826d, a feed speed command value 826e for the laser head 51, first path data 826f specifying a first movement path along which the removal device 5, including the laser head 51, should move) is stored in the memory 82.

[0122] The data necessary for the burring process may be input to the control device 8 via the input device 86, may be input to the control device 8 from another computer via the communication circuit 84, or may be calculated or derived by the control device 8. The data necessary for the burring process (e.g., workpiece data 826a, second path data 826g that defines the second movement path along which the burring tool 10 should move, etc.) is stored in the memory 82.

[0123] Data necessary for tapping may be input to the control device 8 via the input device 86, may be input to the control device 8 from another computer via the communication circuit 84, or may be calculated or derived by the control device 8. Data necessary for tapping (e.g., workpiece data 826a, third path data 826h defining a third movement path along which the tap tool 18 should move, etc.) is stored in the memory 82. Note that, if data specifying the length of the flange 97 in the direction along the central axis of the through hole 96 is stored in the memory 82, the control device 8 may derive the third path data 826h (e.g., the third path data 826h defining the insertion depth of the tap tool 18 relative to the first wall 99a) based on the data. Note that, if data specifying the tool diameter of the burring tool 10 is stored in the memory 82, the control device 8 may derive the length of the flange 97 in the direction along the central axis of the through hole 96 based on the data.

[0124] The input device 86 is not limited to the touch panel display 862. For example, the control device 8 may include an input device 86 such as a button, a switch, a lever, a pointing device, or a keyboard, and a display that displays data input to the input device 86 or other information. Furthermore, a plurality of computers may work together to function as the control device 8. Furthermore, the memory 82 may be distributed across a plurality of locations. For example, part of the memory 82 may be included in cloud storage.

[0125] The processor 80 of the control device 8 executes the program 822 stored in the memory 82, causing the control device 8 to generate a control command. Furthermore, the communication circuit 84 transmits the control command to the devices to be controlled (more specifically, the rotation drive device 36, the movement device 4, the removal device 5 such as the laser irradiation device 50a, the second rotation drive device 25, the tool changer 6, etc.). In this way, the processor 80 executes the program 822, allowing the control device 8 to control the rotation drive device 36, the movement device 4, the removal device 5 such as the laser irradiation device 50a, the second rotation drive device 25, the tool changer 6, etc.

[0126] 24 , workpiece data 826a is stored in the memory 82. The workpiece data 826a includes, for example, shape data of the workpiece 9, data specifying the position of the through hole 96 to be formed by the burring process, and data specifying the size of the through hole 96 to be formed by the burring process (for example, data specifying the inner diameter of the through hole 96). The workpiece data 826a may also include data specifying the length of the flange to be formed by the burring process.

[0127] The control device 8 may derive the position and size of the removal target region RT based on at least the work data 826a (more specifically, based on the shape data of the work 9, data specifying the position of the through hole 96 to be formed by the burring process, and data specifying the size of the through hole 96 to be formed by the burring process), and store data 826b indicating the derived position and size of the removal target region RT in the memory 82.

[0128] In addition, the control device 8 may derive a first movement path along which the removal device 5, such as the laser head 51, should move based on data 826b indicating the position of the removal target area RT and the size of the removal target area RT, and store first path data 826f indicating the derived first movement path in the memory 82.

[0129] Furthermore, the control device 8 may generate a first movement command S1 based on the first path data 826f and transmit the first movement command S1 to the movement device 4 so that the removal device 5, such as the laser head 51, moves along the first movement path. The movement device 4 that receives the first movement command S1 moves the removal device 5, such as the laser head 51, along the first movement path. In this way, the first coating layer 93 is removed in the removal target region RT.

[0130] In the above example, the position of the removal target region RT, the size of the removal target region RT, and the above-mentioned first movement path are automatically derived by the control device 8 based on the workpiece data 826a, so the operator does not need to input these data into the control device 8. This reduces the workload on the operator and prevents the generation of defective workpieces due to input errors by the operator.

[0131] 24 , workpiece data 826a is stored in the memory 82. The workpiece data 826a includes, for example, shape data of the workpiece 9, data specifying the positions of the through holes 96 to be formed by burring, material data of the base material 91, plate thickness data of the base material 91, material data of the first coating layer 93, thickness data of the first coating layer 93, and the like.

[0132] The control device 8 may determine laser output parameters 826d based on at least the workpiece data 826a, and store the determined laser output parameters 826d in the memory 82. The laser output parameters 826d include, for example, power, pulse frequency, duty ratio, focal length, etc. The control device 8 may also determine a feed speed command value for the laser head 51 based on at least the workpiece data 826a, and store the determined feed speed command value 826e in the memory 82.

[0133] The control device 8 may determine laser output parameters based on at least characteristic data 826c of an obstacle (e.g., the above-mentioned second wall 99b) between the removal target region RT and the laser head 51, and store the determined laser output parameters 826d in the memory 82. The control device 8 may also determine a feed speed command value for the laser head 51 based on at least characteristic data 826c of the obstacle (e.g., the above-mentioned second wall 99b) between the removal target region RT and the laser head 51, and store the determined feed speed command value 826e in the memory 82. Note that the characteristic data 826c of the obstacle between the removal target region RT and the laser head 51 includes at least one of the presence or absence of the obstacle, the thickness of the obstacle, and the material of the obstacle, for example.

[0134] For example, if an obstacle (such as the above-mentioned second wall 99b) exists between the removal target region RT and the laser head 51, the obstacle must be removed by the laser. Therefore, in this case, it is preferable to relatively increase the laser output or relatively decrease the feed speed of the laser head 51.

[0135] For example, the laser output may be relatively increased or the feed speed of the laser head 51 may be relatively decreased as the thickness of the obstacle between the region to be removed RT and the laser head 51 increases.

[0136] For example, if the material of the obstacle between the area to be removed RT and the laser head 51 is a material that is easily melted by the laser (for example, a material with high laser absorption characteristics or a material with a low melting point), the laser output may be relatively reduced or the feed speed of the laser head 51 may be relatively increased.

[0137] The control device 8 may determine laser output parameters based on at least both the above-described workpiece data 826a and characteristic data 826c of an obstacle (e.g., the above-described second wall 99b) between the removal target region RT and the laser head 51, and store the determined laser output parameters 826d in the memory 82. Furthermore, the control device 8 may determine a feed rate command value for the laser head 51 based on at least both the above-described workpiece data 826a and characteristic data 826c of an obstacle (e.g., the above-described second wall 99b) between the removal target region RT and the laser head 51, and store the determined feed rate command value 826e in the memory 82.

[0138] In the above example, at least one of the laser output parameter 826d and the feed rate command value 826e for the laser head 51 is automatically derived by the control device 8 based on at least one of the workpiece data 826a and the characteristic data 826c of an obstacle (for example, the above-mentioned second wall 99b) between the removal target region RT and the laser head 51. This reduces the workload on the operator.

[0139] (Removal Mode M1) The control device 8 can execute the removal mode M1 by controlling the removal device 5 (more specifically, the laser irradiation device 50a) and the movement device 4. As illustrated in Figures 2 and 12 to 15, the removal mode M1 is a mode in which a removal means such as a laser B, a chemical solution L, or a second tool T2 is applied to the first coating layer 93 so as to remove the first coating layer 93 from the first region RG1 of the plate portion 90. An example of applying the laser B to the first coating layer 93 will be described below.

[0140] 17 or 26, the control device 8 executing the program 822 (more specifically, the first program 822a) transmits the above-described laser output parameters 826d and an emission command E1 to the laser irradiation device 50a. The control device 8 executing the program 822 (more specifically, the first program 822a) also transmits a first movement command S1 to the movement device 4 based on a feed speed command value 826e for the laser head 51 and first path data 826f stored in the memory 82.

[0141] The laser irradiation device 50a receives the laser output parameter 826d and the emission command E1 and emits a laser beam having an output corresponding to the laser output parameter 826d toward the removal target region RT. The movement device 4 receives the first movement command S1 and moves the laser head 51 along the first movement path. In this way, the first coating layer 93 is removed from the first region RG1 of the plate portion 90. If an obstacle (e.g., the second wall 99b) is present on the laser emission axis of the laser head 51, the obstacle is removed by the laser emitted toward the removal target region RT.

[0142] (Reverse Mode M2) The control device 8 may be able to execute the reverse mode M2 ​​by controlling the workpiece supporting device 2 (more specifically, the second rotation driving device 25).

[0143] 19 or 27, the control device 8 executing the program 822 (more specifically, the second program 822b) transmits a reversal command RW to the second rotation drive device 25. The second rotation drive device 25 receiving the reversal command RW reverses the workpiece 9. More specifically, the second rotation drive device 25 receiving the reversal command RW rotates the first chuck 21 and the second chuck 23 by 180 degrees around an axis AT parallel to the longitudinal direction of the workpiece 9, thereby reversing the workpiece 9.

[0144] (Burring Mode M3) The control device 8 can execute the burring mode M3 by controlling the rotation drive device 36 and the movement device 4.

[0145] 20 or 28, the control device 8 executing the program 822 (more specifically, the third program 822c) transmits a first rotation command R1 to the rotation drive device 36. Furthermore, the control device 8 executing the program 822 (more specifically, the third program 822c) transmits a second movement command S2 to the movement device 4 based on the second path data 826g stored in the memory 82.

[0146] The rotation drive device 36 receiving the first rotation command R1 rotates the burring tool 10 around the longitudinal center axis of the burring tool 10. More specifically, the rotation drive device 36 receiving the first rotation command R1 rotates the rotating body 31 of the machining head 30 around the first axis AX1, thereby rotating the burring tool 10 around the rotation axis AX. The movement device 4 receiving the second movement command S2 moves the burring tool 10 along the second movement path. More specifically, the first drive device 41b receiving the second movement command S2 moves the machining head 30 along the Z-axis direction, thereby moving the burring tool 10 along the second movement path. In this way, the rotating burring tool 10 burrs the first region RG1 of the plate portion 90. In other words, the rotating burring tool 10 forms a through hole 96 and a flange 97 in the first region RG1 of the plate portion 90.

[0147] (Tool Change Mode M4) The control device 8 may be capable of executing a tool change mode M4 in which the burring tool 10 held by the machining head 30 is replaced with a tap tool 18. The control device 8 controls the moving device 4 and the tool change device 6 to execute the tool change mode M4.

[0148] 21 , the control device 8 executing the program 822 (more specifically, the fourth program 822d) transmits a movement command S4 to the movement device 4. The control device 8 executing the program 822 (more specifically, the fourth program 822d) also transmits a tool change command C1 to the tool change device 6. The movement device 4 receiving the movement command S4 moves the machining head 30 to the tool change position P1. The tool change device 6 receiving the tool change command C1 also replaces the burring tool 10 held by the machining head 30 with a tap tool 18.

[0149] (Tapping Mode M5) The control device 8 controls the rotation drive device 36 and the movement device 4 to thereby execute the tapping mode M5.

[0150] 22 or 29, the control device 8 executing the program 822 (more specifically, the fifth program 822e) transmits a second rotation command R2 to the rotation drive device 36. Furthermore, the control device 8 executing the program 822 (more specifically, the fifth program 822e) transmits a third movement command S3 to the movement device 4 based on the third path data 826h stored in the memory 82.

[0151] The rotation drive device 36 receiving the second rotation command R2 rotates the tap tool 18 around the longitudinal center axis of the tap tool 18. More specifically, the rotation drive device 36 receiving the second rotation command R2 rotates the rotating body 31 of the machining head 30 around the first axis AX1, thereby rotating the tap tool 18 around the rotation axis AX. Furthermore, the movement device 4 receiving the third movement command S3 moves the tap tool 18 along the third movement path. More specifically, the first drive device 41b receiving the third movement command S3 moves the machining head 30 along the Z-axis direction, thereby moving the tap tool 18 along the third movement path. In this way, the rotating tap tool 18 forms a female thread 96s on the wall surface 96w that defines the through hole 96.

[0152] (Workpiece machining method) The workpiece machining method in the embodiment may include a step in which, before performing the above-described removal step (second step ST2), the control device 8 determines at least one of a laser output parameter 826d and a feed speed command value 826e for the laser head 51 based on the above-described workpiece data 826a stored in the memory 82 and / or characteristic data 826c of an obstacle (e.g., the above-described second wall 99b) between the removal target region RT and the laser head 51. Furthermore, the workpiece machining method in the embodiment may include a step in which the determined laser output parameter 826d and / or the feed speed command value 826e for the laser head 51 is stored in the memory 82.

[0153] The above-mentioned removal step (second step ST2) may include the control device 8 generating the above-mentioned first movement command S1 based on at least the above-mentioned first path data 826f stored in the memory 82. The above-mentioned removal step (second step ST2) may include the control device 8 generating the above-mentioned first movement command S1 based on at least the above-mentioned first path data 826f stored in the memory 82 and the above-mentioned feed speed command value 826e of the laser head 51.

[0154] The removal step (second step ST2) may also include the movement device 4 receiving the first movement command S1 from the control device 8 moving the laser head 51 along the first movement path at a feed rate corresponding to the feed rate command value 826e, and the laser irradiation device 50a receiving the laser output parameter 826d and the emission command E1 from the control device 8 emitting a laser having an output corresponding to the laser output parameter 826d toward the removal target region RT. In this way, the first coating layer 93 is removed from the removal target region RT.

[0155] The above-mentioned boring process (fourth step ST4) may include the control device 8 generating the above-mentioned second movement command S2 based at least on the above-mentioned second path data 826g stored in the memory 82.

[0156] The above-described burring process (fourth step ST4) may also include the rotation drive device 36 receiving the first rotation command R1 from the control device 8 rotating the burring tool 10 about the rotation axis AX, and the movement device 4 receiving the above-described second movement command S2 moving the burring tool 10 along the second movement path. In this manner, the burring tool 10 in the rotating state moves across the first region RG1 from which the first coating layer 93 has been removed. As a result, the burring tool 10 in the rotating state forms the through hole 96 and the flange 97 in the first region RG1.

[0157] The above-mentioned tapping process (fifth step ST5) may include the control device 8 generating the above-mentioned third movement command S3 based on at least the above-mentioned third path data 826h stored in the memory 82.

[0158] The tapping process (fifth step ST5) may also include the rotation drive device 36 receiving the second rotation command R2 from the control device 8 rotating the tap tool 18 around the rotation axis AX, and the movement device 4 receiving the third movement command S3 moving the burring tool 10 along the third movement path. In this manner, the rotating tap tool 18 moves across the through hole 96. As a result, the rotating tap tool 18 forms a female thread 96s on a wall surface 96w that defines the through hole 96.

[0159] (Program 822) Program 822 in the embodiment is a program for causing machine tool 1 (more specifically, control device 8 of machine tool 1) to execute at least the removal process (second step ST2) and the burring process (fifth step ST5) of the above-mentioned workpiece machining method.

[0160] More specifically, the program 822 in the embodiment is a program for causing the machine tool 1 (more specifically, the control device 8 of the machine tool 1) to execute a workpiece processing method including: (1) a step of removing the first coating layer 93 from a first region RG1 of the plate portion 90 while the workpiece 9 has a plate portion 90 including a base material 91 and a first coating layer 93 covering at least a portion of the base material 91, while the workpiece 9 is supported by the workpiece support device 2 (removal step: second step ST2); and (2) a step of burring the plate portion 90 after the first coating layer 93 has been removed from the first region RG1 of the plate portion 90 (burring step: fourth step ST4).

[0161] As illustrated in Figure 5, the process of burring the plate portion 90 (fourth step ST4) includes forming a through hole 96 and a flange 97 in the first region RG1 of the plate portion 90 by moving the rotating burring tool 10 in the first direction DR1 described above.

[0162] The details of the removal process (second step ST2) and the burring process (fourth step ST4) have already been explained in the first embodiment or the second embodiment described above, so the details of these processes will not be explained here.

[0163] The program 822 in the embodiment may be a program for causing the machine tool 1 (more specifically, the control device 8 of the machine tool 1) to execute a workpiece machining method including: (1) the above-mentioned removal step (second step ST2), (2) a step of inverting the workpiece 9 (more specifically, a step of rotating the workpiece 9 180 degrees around an axis AT parallel to the longitudinal direction of the workpiece 9), and (3) the above-mentioned burring step (fourth step ST4). The step of inverting the workpiece 9 is executed between the above-mentioned removal step (second step ST2) and the above-mentioned burring step (fourth step ST4).

[0164] The details of the process of turning over the workpiece 9 have already been explained in the first embodiment or the second embodiment, so the details of this process will not be explained again.

[0165] The program 822 in the embodiment may be a program for causing the machine tool 1 (more specifically, the control device 8 of the machine tool 1) to execute a workpiece machining method including (1) the above-mentioned removal process (second step ST2), (2) the above-mentioned burring process (fourth step ST4), and (3) a process for forming a female thread 96s on the wall surface 96w that defines the through hole 96 (tapping process: fifth step ST5).

[0166] In addition, a process of replacing the burring tool 10 held by the processing head 30 with a tapping tool 18 may be carried out between the above-mentioned burring process (fourth step ST4) and the above-mentioned tapping process (fifth step ST5).

[0167] The details of the process of replacing the burring tool 10 held by the processing head 30 with the tapping tool 18 and the tapping process (fifth step ST5) have already been explained in the first embodiment or the second embodiment described above, so the details of these processes will not be explained here.

[0168] In the embodiment, the program 822 may be a program for causing the machine tool 1 (more specifically, the control device 8 of the machine tool 1) to execute a workpiece machining method including: (1) the above-mentioned removal process (second step ST2); (2) a process of inverting the workpiece 9 (more specifically, a process of rotating the workpiece 9 180 degrees around an axis AT parallel to the longitudinal direction of the workpiece 9); (3) the above-mentioned burring process (fourth step ST4); (4) a process of replacing the burring tool 10 held in the machining head 30 with a tapping tool 18; and (5) the above-mentioned tapping process (fifth step ST5).

[0169] Additionally, the program 822 in the embodiment may include subprograms for causing the control device 8 of the machine tool 1 to execute the following steps: (1) deriving the position and size of the removal target region RT based on at least the work data 826a (more specifically, based on the shape data of the work 9, data specifying the position of the through hole 96 to be formed by the burring process, and data specifying the size of the through hole 96 to be formed by the burring process); (2) deriving a first movement path along which the removal device 5, such as the laser head 51, should move based on data 826b indicating the position and size of the removal target region RT; and (3) transmitting a first movement command S1 to the movement device 4 so that the removal device 5, such as the laser head 51, moves along the first movement path.

[0170] Additionally, the program 822 in the embodiment may include subprograms for causing the control device 8 of the machine tool 1 to execute the following steps: (1) determining a laser output parameter 826d based on at least the work data 826a; and (2) transmitting an emission command E1 and the laser output parameter 826d to the laser irradiation device 50a so that a laser having an output corresponding to the laser output parameter 826d is emitted toward the region RT to be removed.

[0171] Additionally, the program 822 in the embodiment may include subprograms for causing the control device 8 of the machine tool 1 to execute the following steps: (1) determining a laser output parameter 826d based on at least characteristic data 826c of an obstacle (e.g., the above-mentioned second wall 99b) between the removal target area RT and the laser head 51; and (2) transmitting an emission command E1 and the laser output parameter 826d to the laser irradiation device 50a so that a laser having an output corresponding to the laser output parameter 826d is emitted toward the removal target area RT.

[0172] The memory 82 in the embodiment may be a non-volatile storage medium that records the above-described program 822. The non-volatile storage medium that records the above-described program 822 may be a portable storage medium 82M, as exemplified in FIG.

[0173] The present invention is not limited to the above-described embodiments or modifications, and it is clear that each embodiment or modification can be appropriately modified or changed within the scope of the technical concept of the present invention. Furthermore, various techniques used in each embodiment or modification can be applied to other embodiments or modifications as long as no technical contradiction occurs. Furthermore, optional additional configurations in each embodiment or modification can be omitted as appropriate.

[0174] 1, 1A, 1B...machine tool, 2...workpiece support device, 4...moving device, 5...removing device, 6...tool changing device, 8...control device, 9...workpiece, 9a...pipe, 10...burring tool, 11...tip portion, 13...column portion, 15...shoulder portion, 18...tapping tool, 21...first chuck, 22...second rotating body, 23...second chuck, 24...third rotating body, 25...second rotation drive device, 25a...first motor, 25b...second motor, 30...machining head, 31...rotating body, 33...frame, 36...rotation drive device, 36m...motor, 40...first moving device, 41a...first moving body, 41b...first drive device, 4 3a...second moving body, 43b...second driving device, 45b...third driving device, 46...second moving device, 46m...motor, 50a...laser irradiation device, 50b...chemical liquid application device, 50c...cutting device, 51...laser head, 52...laser emission port, 53...laser light source, 55...optical component, 61...tool change arm, 63...arm rotation device, 65...arm moving device, 80...hardware processor, 82...memory, 82M...storage medium, 84...communication circuit, 86...input device, 88...bus, 90...plate portion, 91...base material, 91s...exposed surface, 93...first coating layer, 93a...plated layer, 94...second Coating layer, 94a...plated layer, 96...through hole, 96s...female screw, 96w...wall surface, 97...flange, 99a...first wall, 99b...second wall, 99c...third wall, 99d...fourth wall, 211...gripping member, 231...guide roller, 822...program, 822a...first program, 822b...second program, 822c...third program, 822d...fourth program, 822e...fifth program, 826...data, 826a...work data, 826b...data indicating the position and size of the area to be removed, 826c...characteristic data of obstacle, 826d...laser output parameters, 82 6e...feed rate command value, 826f...first path data, 826g...second path data, 826h...third path data, 862...touch panel display, AT...axis parallel to the longitudinal direction of the workpiece, AX...rotation axis, AX1...first axis, AX2...second axis, B...laser, C1...tool change command, E1...injection command, G...assist gas, HD1...first tool holder, HD2...second tool holder, L...chemical solution, M1...removal mode, M2...reversal mode, M3...burring machining mode, M4...tool change mode, M5...tapping mode, OP...access opening, OP1...through-hole type opening,OP2...slit type opening, P1...tool change position, R...rotation command, R1...first rotation command, R2...second rotation command, RB...removed area, RG1...first area, RT...area to be removed, RW...reversal command, S...movement command, S1...first movement command, S2...second movement command, S3...third movement command, S4...movement command, SP...internal area, SP1...internal space, T1...instrument for applying chemical liquid, T2...second tool,

Claims

1. A workpiece processing method comprising: a step of preparing a workpiece having a plate portion including a base material and a first coating layer covering at least a portion of the base material; and a step of burring the plate portion, wherein when a direction from the base material toward the first coating layer is defined as a first direction, the step of burring the plate portion includes forming a through hole and a flange in a first region of the plate portion by moving a rotating burring tool in the first direction, and a step of removing the first coating layer from the first region of the plate portion is carried out prior to the step of burring the plate portion.

2. The method for machining a workpiece according to claim 1, wherein the first coating layer is a plating layer of pure zinc or a zinc alloy.

3. A workpiece machining method according to claim 1 or 2, wherein in the step of burring the plate portion, the formation of the through hole and the formation of the flange are carried out simultaneously.

4. A workpiece processing method according to any one of claims 1 to 3, wherein the step of removing the first coating layer includes removing the first coating layer from the first region of the plate portion by irradiating the first coating layer with a laser.

5. The workpiece machining method according to any one of claims 1 to 4, further comprising a step of forming a female thread on a wall surface defining the through hole.

6. A method for machining a workpiece according to any one of claims 1 to 5, wherein the first coating layer faces an internal region of the workpiece.

7. A workpiece machining method as claimed in any one of claims 1 to 6, wherein, when a direction opposite to the first direction is defined as a second direction, the plate portion includes a second coating layer arranged on the second direction side of the base material and covering at least a portion of the base material, and the step of burring the plate portion includes moving the burring tool in a rotating state in the first direction so that the burring tool in a rotating state crosses the second coating layer and the base material in turn.

8. A workpiece machining method according to any one of claims 1 to 7, further comprising a step of inverting the workpiece after the first coating layer has been removed from the first region of the plate portion and before the step of burring the plate portion.

9. A workpiece machining method as claimed in any one of claims 1 to 8, wherein the workpiece has a first wall in which the first region is located and a second wall arranged opposite the first wall, and an access opening arranged opposite the first region is formed in the second wall.

10. A method for machining a workpiece according to claim 9, wherein when an area formed by removing the first coating layer is defined as a removed area, the size of the access opening is smaller than the size of the removed area.

11. A machine tool comprising: a work support device that supports a work having a plate portion including a base material and a first coating layer covering at least a portion of the base material; a machining head that supports a burring tool rotatably about a rotation axis; a rotation drive device that rotates the burring tool about the rotation axis; a moving device that moves the machining head relatively to the work support device; a removal device that removes a portion of the first coating layer from the work; and a control device that controls the rotation drive device, the moving device, and the removal device, wherein the control device is capable of executing a removal mode that removes the first coating layer from a first region of the plate portion by sending a control command to at least the removal device; and a burring processing mode that burrs the plate portion by sending a control command to at least the rotation drive device and the moving device, wherein when a direction from the base material toward the first coating layer is defined as a first direction, the burring processing mode is a mode in which the burring tool that moves in the first direction while rotating is used to form a through hole and a flange in the first region from which the first coating layer has been removed.

12. The machine tool according to claim 11, wherein the removal device includes a laser irradiation device having a laser head, and the removal mode includes transmitting an emission command from the control device to the laser irradiation device so that the first coating layer is removed from the first region of the plate portion by a laser emitted from the laser head.

13. A machine tool as described in claim 12, wherein, when a portion of the area occupied by the first coating layer that will be removed by the removal device is defined as a removal target area, the control device determines at least one of a laser output parameter and a feed speed command value for the laser head based at least on characteristic data of an obstacle between the removal target area and the laser head.

14. A machine tool as described in claim 11 or 12, wherein, when a portion of the area occupied by the first coating layer that will be removed by the removal device is defined as a removal target area, the control device derives a position of the removal target area and a size of the removal target area based on at least work data, the control device derives a first movement path along which the removal device should move based on data indicating the position of the removal target area and the size of the removal target area, and the control device transmits a first movement command to the movement device so that the removal device moves along the first movement path.

15. A program for causing a machine tool to execute a workpiece machining method comprising the steps of: removing the first coating layer from a first region of a plate portion, the plate portion including a base material and a first coating layer covering at least a portion of the base material, while the workpiece is supported by a workpiece supporting device; and burring the plate portion after the first coating layer has been removed from the first region of the plate portion, wherein when the direction from the base material toward the first coating layer is defined as a first direction, the step of burring the plate portion includes forming a through hole and a flange in the first region of the plate portion by moving a rotating burring tool in the first direction.

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