Arithmetic device, machine tool, machine tool control device, and arithmetic program

Abstract

A computation device (110) computes a position (C) of a tool (CI) for cutting a ridge line (RL) formed by a circumferential wall surface (SW) and a cylinder circumferential surface (SS), the circumferential wall surface (SW) forming a through-hole (HE) having the shape of a cylinder (CS) and penetrating through an object (CP) being machined. The computation device (110) calculates the position on the basis of a second tangent (B2) of a first ellipse (E1) formed by the cylinder circumferential surface and a planar surface (VP) perpendicular to a first tangent (B1) of the ridge line, a third tangent (B3) of a second ellipse (E2) formed by the cylinder and the planar surface, a prescribed machining width (W), and the radius (D) of the tool.

Description

[Technical Field]

[0001] The present invention relates to a computing device, a machine tool, a control device for a machine tool, and a computing program. [Background technology]

[0002] International Publication No. 2016 / 133162 discloses a tool trajectory calculation program that can calculate the trajectory of a tool that removes burrs from a workpiece. Summary of the Invention

[0003] WO 2016 / 133162 discloses two methods for calculating the machining depth in deburring or chamfering a workpiece. The method disclosed as "Method 1" results in a small chamfer width, which is therefore inaccurate. The method disclosed as "Method 2" uses Newton's method to find the solution, which is therefore also inaccurate.

[0004] These methods have the problem that they do not calculate the exact position of the tool that will achieve stable cutting. When cutting using a tool moved to the calculated position, there is a risk that the workpiece will be cut too little or too much.

[0005] The present invention aims to solve the above-mentioned problems.

[0006] A first aspect of the present invention is a computing device that computes a first position of a tool that cuts, with a predetermined machining width, a peripheral wall surface that forms a through hole penetrating the workpiece, at least one of an outer peripheral surface and an inner peripheral surface of which is formed as a cylindrical peripheral surface, in the shape of a cylinder or a column that includes a plurality of parallel cylinders at each corner from one of the outer peripheral surface and the inner peripheral surface to the other, and a ridgeline formed by the cylindrical peripheral surface, wherein the computing device computes a first position of a tool that cuts, with a predetermined machining width, a peripheral wall surface that forms a through hole penetrating the workpiece, and a ridgeline formed by the cylindrical peripheral surface, the second position of the workpiece, a third position of the through hole, a first radius of the cylindrical peripheral surface of the workpiece, a second radius of the cylinder, a first direction in which a first central axis of the workpiece extends, and a second central axis of the cylinder that extends in a second direction perpendicular to the first direction. and a first calculation unit that calculates the first position of the tool for cutting the ridgeline including the machining point based on: a plane including the machining point that is perpendicular to a first tangent to the ridgeline at the machining point on the ridgeline, the plane being determined based on a fourth position of the machining point and the machining data; a second tangent at the machining point to a first ellipse formed by the plane and the cylinder circumferential surface, the plane being perpendicular to a first tangent to the ridgeline at the machining point on the ridgeline, the third tangent at the machining point to a second ellipse formed by the cylinder and the plane; the predetermined machining width; and the third radius of the tool.

[0007] A second aspect of the present invention is a machine tool comprising an arithmetic device according to the first aspect, the tool, and a machining control unit that moves the tool to the first position and causes the tool to cut the ridge line.

[0008] A third aspect of the present invention is a control device for a machine tool, comprising an arithmetic device according to the first aspect, and a machining control unit that moves the tool to the first position and causes the tool to cut the ridge line.

[0009] A fourth aspect of the present invention is a calculation program, the program being for calculating a first position of a tool for cutting, with a predetermined machining width, a peripheral wall surface of a workpiece, at least one of an outer peripheral surface and an inner peripheral surface of which is formed as a cylindrical peripheral surface, in the shape of a cylinder or a columnar body having a plurality of parallel cylinders at each corner, from one of the outer peripheral surface and the inner peripheral surface to the other, which forms a through hole penetrating the workpiece, and a ridgeline formed by the cylindrical peripheral surface, the program being provided to a processing circuit included in a calculation device which calculates a first position of the tool for cutting, with a predetermined machining width, a peripheral wall surface of the workpiece, which forms a through hole penetrating the workpiece, and a ridgeline formed by the cylindrical peripheral surface, the program being provided to a processing circuit which includes a first position of the workpiece, a third position of the through hole, a first radius of the cylindrical peripheral surface of the workpiece, a second radius of the cylinder, a first direction in which a first central axis of the workpiece extends, and a second direction perpendicular to the first direction. an acquisition procedure for acquiring machining object data including an eccentricity distance of a second central axis of the cylinder from the first central axis and a third radius of the tool; and a calculation procedure for calculating the first position of the tool for cutting the ridge line including the machining point, based on a second tangent at the machining point to a first ellipse formed by the cylinder circumferential surface and a plane including the machining point that is perpendicular to a first tangent to the ridge line at the machining point on the ridge line and that is determined based on a fourth position of the machining point and the machining object data, the plane being perpendicular to a first tangent to the ridge line at the machining point on the ridge line, the plane being determined based on a fourth position of the machining point and the machining object data, the third tangent at the machining point to a second ellipse formed by the cylinder and the plane, the specified machining width, and the third radius of the tool.

[0010] According to the present invention, it is possible to accurately calculate the position of a tool that achieves stable cutting processing for removing burrs. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a machine tool. [Figure 2] Fig. 2A is a diagram illustrating the configuration of a control device for a machine tool, and Fig. 2B is a diagram for explaining processing performed based on a G-code. [Figure 3] 3A and 3B are diagrams for explaining a thick-walled cylinder and a through-hole formed in the thick-walled cylinder. [Figure 4]Fig. 4A shows a burr generated on the inner peripheral surface of a thick-walled cylinder and a tool for removing the burr, and Fig. 4B shows a burr generated on the outer peripheral surface of a thick-walled cylinder and a tool for removing the burr. [Figure 5] Fig. 5A is a diagram showing the positional relationship between the first central axis of the thick-walled cylinder and the second central axis of the cylinder that forms the through hole when the eccentric distance is zero, and Fig. 5B is a diagram showing the positional relationship between the first central axis of the thick-walled cylinder and the second central axis of the cylinder that forms the through hole when the eccentric distance is not zero. [Figure 6] FIG. 6 is a diagram showing data acquired by an acquisition unit of the arithmetic device. [Figure 7] Fig. 7A is a diagram for explaining the relationship between the cutting depth and a predetermined machining width, and Figs. 7B and 7C are diagrams for explaining the tolerance. [Figure 8] FIG. 8 is a diagram illustrating a through hole that penetrates a thick-walled cylinder in a cylindrical shape and a first tangent to the ridge line of the through hole. [Figure 9] FIG. 9 is a diagram for explaining a vertical plane perpendicular to a first tangent to the ridge line of the through-hole, and a first ellipse and a second ellipse formed on the vertical plane. [Figure 10] FIG. 10 is a diagram showing the positional relationship between the second tangent to the first ellipse, the third tangent to the second ellipse, and a tool that removes burrs generated on the inner peripheral surface of a thick-walled cylinder. [Figure 11] FIG. 11 is a diagram for explaining that a first position of the tool corresponding to a machining target point on the ridge line of the through hole is calculated based on a predetermined machining width. [Figure 12] FIG. 12 is a diagram showing the positional relationship between the second tangent to the first ellipse, the third tangent to the second ellipse, and a tool that removes burrs generated on the outer peripheral surface of a thick-walled cylinder. [Figure 13] FIG. 13 is a diagram for explaining that a first position of the tool corresponding to a machining target point on the ridge line of the through hole is calculated based on a predetermined machining width. [Figure 14] FIG. 14 is a flowchart showing a processing procedure executed by the control device of the machine tool. [Figure 15]FIG. 15 is a diagram illustrating a computer program product of an arithmetic program for causing the arithmetic unit of the control device to execute the processing procedure shown in FIG. [Figure 16] FIG. 16 is a diagram illustrating the configuration of a control device for a machine tool. [Figure 17] 17A is a diagram showing the angle formed by the perpendicular line from the processing point on the ridge line of the through hole to the first central axis of the thick-walled cylinder with respect to the X axis. FIG. 17B is a diagram showing the third angle formed by the perpendicular line from the processing point on the ridge line of the through hole to the second central axis of the cylinder that forms the shape of the through hole with respect to the X axis, and the first basis vector. [Figure 18] FIG. 18 is a diagram showing the positional relationship between the second tangent line, the third tangent line, and a tool that removes burrs generated on the inner peripheral surface of the thick-walled cylinder, as well as the first and second basis vectors. [Figure 19] FIG. 19 is a diagram for explaining that a first position of the tool corresponding to a machining target point on the ridge line of the through hole is calculated based on a predetermined machining width. [Figure 20] FIG. 20 is a diagram showing the positional relationship between the second tangent line, the third tangent line, and a tool that removes burrs generated on the outer peripheral surface of the thick-walled cylinder, as well as the first and second basis vectors. [Figure 21] FIG. 21 is a diagram for explaining that a first position of the tool corresponding to a machining target point on the ridge line of a through hole is calculated based on a predetermined machining width. [Figure 22] FIG. 22 is a flowchart showing a processing procedure executed by the control device of the machine tool. [Figure 23] FIG. 23 is a diagram illustrating a manifold block used as the workpiece. [Figure 24] FIG. 24 is a diagram illustrating a thick-walled cylinder and an elongated through-hole that penetrates the thick-walled cylinder. [Figure 25] FIG. 25 is a diagram schematically showing a through-hole in the shape of an elongated hole. [Figure 26] FIG. 26 is a diagram illustrating a thick-walled cylinder and a through-hole having a rounded rectangular shape that penetrates the thick-walled cylinder. [Figure 27]FIG. 27 is a diagram schematically showing a through-hole having a rounded rectangular shape. [Figure 28] FIG. 28 is a diagram for explaining the positional relationship between the first position of the tool and the first central axis of the thick-walled cylinder. DETAILED DESCRIPTION OF THE INVENTION

[0012] FIG. 1 is a diagram showing an example of a machine tool 10. The machine tool 10 has a main body 20 and a control device 30. The control device 30 includes an arithmetic unit according to an embodiment, which will be described later, and controls the main body 20. The control device 30 is, for example, a CNC. The main body 20 has a bed 52, a saddle 54, a table 56, a movable unit 74, a movable unit 76, and a movable unit 78. The bed 52 is placed on the XY plane of an XYZ Cartesian coordinate system. The saddle 54, the table 56, the movable unit 74, the movable unit 76, and the movable unit 78 are installed on the bed 52.

[0013] Movable part 74 is movable in a direction DX parallel to the X-axis by a motor (not shown). Movable part 76 is placed on top of movable part 74. Movable part 76 is movable in a direction DY parallel to the Y-axis relative to movable part 74 by a motor (not shown). Movable part 78 is attached to the side of movable part 76. Movable part 78 is movable in a direction DZ parallel to the Z-axis relative to movable part 76 by a motor (not shown). The direction DZ parallel to the Z-axis is parallel to the direction of gravity. The direction of gravity is the direction in which gravity acts on an object.

[0014] The movable part 78 includes a spindle head. A tool CI is attached to the spindle head. In this embodiment, the tool CI is a ball end mill having a spherical cutting surface formed at its tip. The tool CI may be another tool, for example, a polishing tool with a spherical head. Furthermore, the tool CI is not limited to having a completely spherical cutting surface, and may have a cutting surface formed by a portion of a sphere.

[0015] In this embodiment, a thick-walled cylinder CP is placed on a table 56 as a workpiece. The tool CI is driven by a motor (not shown) to rotate. As the tool CI rotates, it uses a spherical cutting surface to cut the ridgeline that forms the edge of the through-hole HE in the thick-walled cylinder CP. By cutting the ridgeline, the tool CI removes burrs formed on the inner or outer peripheral surface of the thick-walled cylinder CP.

[0016] In this embodiment, during cutting, the tool CI moves in the XYZ space by the movable parts 74, 76, and 78. That is, the tool CI moves in the direction DX parallel to the X axis, the direction DY parallel to the Y axis, and the direction DZ parallel to the Z axis, thereby moving the tool CI relative to the workpiece in the X-axis direction, the Y-axis direction, and the Z-axis direction.

[0017] Note that, since it is sufficient that the tool CI moves relative to the workpiece in the X-axis direction, the Y-axis direction, and the Z-axis direction, the tool CI may move in a direction DZ parallel to the Z-axis, and the workpiece may move in a direction DX parallel to the X-axis and a direction DY parallel to the Y-axis. In this case, for example, a movable mechanism is provided on the saddle 54 and the table 56.

[0018] A robot arm may hold the tool CI instead of the movable parts 74, 76, and 78. Alternatively, the workpiece held by the robot arm may move in the X-axis direction, the Y-axis direction, and the Z-axis direction. In either case, the tool CI moves relative to the workpiece in the X-axis direction, the Y-axis direction, and the Z-axis direction. In the following description, the tool CI moves relative to the workpiece, which is a thick-walled cylinder CP.

[0019] 2A is a diagram illustrating an example of the configuration of control device 30 of machine tool 10. Control device 30 has an arithmetic unit 110, a storage device 120, and an input / output device 130. Arithmetic unit 110 is configured by a processing circuit. The processing circuit is, for example, a processor such as a CPU or a GPU.

[0020] The storage device 120 includes a volatile memory (not shown) and a non-volatile memory (not shown). The volatile memory is used as a working memory for the processor. Data DT (described later) acquired by the acquisition unit 210 is stored in the volatile memory when a macro program (described later) is read. The volatile memory is, for example, a RAM.

[0021] The nonvolatile memory is used as a storage memory. The nonvolatile memory of the storage device 120 stores the machining program PG and the calculation program (macro program) executed by the processing circuit of the calculation device 110. The nonvolatile memory is, for example, a ROM or a flash memory.

[0022] The input / output device 130 includes, for example, at least a part of an operation panel, a keyboard, a mouse, a display, and a touch panel. A user inputs user input data from the data DT to the arithmetic device 110 via the input / output device 130. The input data DT is stored in the storage device 120. Furthermore, setting data of default setting values ​​from the data DT is also stored in the storage device 120. The input / output device 130 can display the data DT stored in the storage device 120.

[0023] The arithmetic device 110 has an acquisition unit 210, a determination unit 220, a first calculation unit 230, and a processing control unit 250. The acquisition unit 210, the determination unit 220, the first calculation unit 230, and the processing control unit 250 are realized by the arithmetic device 110 executing a calculation program stored in the storage device 120. At least some of the acquisition unit 210, the determination unit 220, the first calculation unit 230, and the processing control unit 250 may be realized by an integrated circuit such as an ASIC or an FPGA, or an electronic circuit including a discrete device.

[0024] The acquisition unit 210 acquires data DT input by the user and data DT stored in the storage device 120. The data DT acquired by the acquisition unit 210 includes tool data, machining object data, and option data, which will be described later.

[0025] As described above, to remove burrs, the tool CI cuts the ridgeline that forms the edge of the through hole HE. The position of the tool CI is calculated corresponding to the machining target point on the ridgeline of the through hole HE. The calculated position of the tool CI is hereinafter referred to as the first position. The machining target point is located on the ridgeline of the through hole HE at a position closest to the first position of the tool CI. The determination unit 220 determines multiple machining target points on the ridgeline based on the tolerance amount included in the optional data described above. The tolerance amount will be described later. The first calculation unit 230 calculates the first position of the tool CI corresponding to each machining target point determined by the determination unit 220 based on the data DT acquired by the acquisition unit 210.

[0026] The machining control unit 250 controls the movable units 74, 76, and 78 of the main body 20, or other movable mechanisms or robot arms, to relatively move the tool CI to a first position at each of the multiple machining points determined by the determination unit 220. The machining control unit 250 rotates the tool CI to cause the tool CI to cut the ridge line.

[0027] To start cutting the ridgeline at the first machining target point among the multiple machining target points determined by the determination unit 220, the tool CI moves to the first position corresponding to the machining target point calculated by the first calculation unit 230. The ridgeline is cut to form a machined surface with a predetermined machining width.

[0028] The tool CI then moves toward the next machining point while cutting the ridge line, and moves to a first position corresponding to that machining point. The ridge line is cut, and a machining surface with a predetermined machining width is formed. After this cutting is repeated, when the tool CI returns to the first machining point, the machining control unit 250 stops cutting and moves the tool CI to a predetermined end position.

[0029] 2B is a diagram for explaining processing performed based on G-code. In this embodiment, a machining program PG is executed by the processing circuit of the arithmetic device 110 in response to a user input. When the machining program PG is executed, processing based on the G-code included in the machining program PG is performed. The machining program PG includes G-code indicating an instruction for calling a macro program MP.

[0030] The processing circuit of the arithmetic device 110 calls the macro program MP stored in the non-volatile memory of the storage device 120 based on the G-code. At the same time, the processing circuit of the arithmetic device 110 writes data DT, which is a value corresponding to the argument of the G-code or a default value, into the volatile memory of the storage device 120. The data DT includes tool data, machining object data, and option data, which will be described later.

[0031] The first calculation unit 230 of the calculation device 110 reads the macro program MP to be called as a calculation program from the storage device 120. The acquisition unit 210 of the calculation device 110 acquires the data DT from the storage device 120. The processing circuit of the calculation device 110 executes the macro program MP using the data DT, and the first calculation unit 230 calculates the first position of the tool CI.

[0032] 3A and 3B are diagrams illustrating a thick-walled cylinder CP and a through-hole HE formed in the thick-walled cylinder CP. FIG. 3A is a diagram of the thick-walled cylinder CP as viewed from the outside. In this case, lines that are not visible from the outside are not shown in FIG. 3A. FIG. 3B shows these invisible lines visualized with dashed lines.

[0033] The central axis of the thick-walled cylinder CP will be referred to as the first central axis A1 below. The direction in which the first central axis A1 of the thick-walled cylinder CP extends will be referred to as the first direction below. In this embodiment, the first direction in which the first central axis A1 of the thick-walled cylinder CP extends is the direction of the Y axis. Note that the first direction may be parallel to the XY plane and may form a predetermined angle with the Y axis on a plane including the first central axis A1. The thick-walled cylinder CP is a hollow cylinder. The inner circumferential surface SN and outer circumferential surface ST of the thick-walled cylinder CP are each formed as a cylindrical circumferential surface SS.

[0034] In this embodiment, a through hole HE having a cylindrical shape penetrating the thick-walled cylinder CP from its outer peripheral surface ST to its inner peripheral surface SN is formed by a peripheral wall surface SW. The ridge lines RL forming the edge of the through hole HE include two types of ridge lines RLN and RLT. The ridge line RLN is formed by the peripheral wall surface SW of the through hole HE and the inner peripheral surface SN of the thick-walled cylinder CP. The ridge line RLT is formed by the peripheral wall surface SW of the through hole HE and the outer peripheral surface ST of the thick-walled cylinder CP.

[0035] The central axis of the cylinder CS that forms the shape of the through hole HE will be referred to below as the second central axis A2. The direction in which the second central axis A2 extends will be referred to below as the second direction. In this embodiment, the second direction in which the second central axis A2 extends is the direction of the Z axis. In other words, the second direction in which the second central axis A2 extends is perpendicular to the first direction in which the first central axis A1 extends. The radius of the imaginary cylinder CS that forms the shape of the through hole HE will be referred to below as the second radius R2.

[0036] FIG. 4A shows a burr BR generated on the inner surface SN of a thick-walled cylinder CP and a tool CI that removes the burr BR. FIG. 4A shows a view of the thick-walled cylinder CP cut by a plane perpendicular to the Y axis (a plane parallel to the XZ plane) as viewed from the negative direction of the Y axis. When the tool CI comes into contact with the ridge line RL (RLN), it removes the burr BR by cutting the ridge line RL, which includes the machining point P, with a predetermined cutting width. It is necessary to appropriately determine a first position C of the tool CI that can cut the ridge line RL with the predetermined cutting width. The first position C of the tool CI is the center position of the sphere that forms the cutting surface at the tip of the tool CI.

[0037] The radius of the cylindrical circumferential surface SS of the thick-walled cylinder CP will be referred to as the first radius R1. As shown in Figure 4A, when removing burrs BR generated on the inner circumferential surface SN of the thick-walled cylinder CP, the radius RN of the inner circumferential surface SN is used as the first radius R1 of the cylindrical circumferential surface SS of the thick-walled cylinder CP. The radius RN of the inner circumferential surface SN is equal to the shortest distance between the first center axis A1 of the thick-walled cylinder CP and the inner circumferential surface SN.

[0038] FIG. 4B is a diagram showing a burr BR generated on the outer peripheral surface ST of a thick-walled cylinder CP and a tool CI that removes the burr BR. Similar to FIG. 4A, FIG. 4B shows a view of the thick-walled cylinder CP cut by a plane perpendicular to the Y axis (a plane parallel to the XZ plane) as viewed from the negative direction of the Y axis. When the tool CI comes into contact with the ridge line RL (RLT), it removes the burr BR by cutting the ridge line RL that includes the machining point P with a predetermined cutting width. It is necessary to appropriately determine a first position C of the tool CI that can cut the ridge line RL with the predetermined cutting width.

[0039] 4B, when removing burrs BR generated on the outer peripheral surface ST of the thick-walled cylinder CP, the radius RT of the outer peripheral surface ST is used as the first radius R1 of the cylindrical circumferential surface SS of the thick-walled cylinder CP. The radius RT of the outer peripheral surface ST is equal to the shortest distance between the first central axis A1 of the thick-walled cylinder CP and the outer peripheral surface ST.

[0040] 4A and 4B, the tool CI is depicted as being approached from the outside of the thick-walled cylinder CP toward the first position C. However, the tool CI may also be approached from the inside of the thick-walled cylinder CP toward the first position C.

[0041] 5A is a diagram showing the positional relationship between the first central axis A1 of the thick-walled cylinder CP and the second central axis A2 of the cylinder CS that forms the through hole HE when the eccentricity distance f is zero. The eccentricity distance indicates the shortest distance of the second central axis A2 from the first central axis A1. FIG. 5A shows the thick-walled cylinder CP with the through hole HE as seen from the positive direction of the Z axis outside the thick-walled cylinder CP.

[0042] The bottom surface of the cylinder CS that forms the shape of the through hole HE is circular. Therefore, when the through hole HE is viewed from directly above the through hole HE along the Z axis, the through hole HE has a circular shape corresponding to the cylinder CS. The second central axis A2 is positioned so as to overlap with the first central axis A1. The radius of the through hole HE viewed from directly above coincides with the second radius R2 of the cylinder CS.

[0043] FIG. 5B is a diagram showing the positional relationship between the first central axis A1 of the thick-walled cylinder CP and the second central axis A2 of the cylinder CS that forms the through hole HE when the eccentricity distance f is not zero. Similar to FIG. 5A, FIG. 5B shows the thick-walled cylinder CP having the through hole HE as viewed from the positive direction of the Z axis outside the thick-walled cylinder CP. Similar to FIG. 5A, when the through hole HE is viewed from directly above it along the Z axis, the through hole HE has a circular shape. The second central axis A2 is offset from the first central axis A1 by the eccentricity distance f in the direction of the X axis.

[0044] FIG. 6 is a diagram showing data DT acquired by the acquisition unit 210 of the calculation device 110. The data DT acquired by the acquisition unit 210 includes tool data, machining object data, and option data. The tool data includes the number of a tool CI stored in the storage device 120. The radius value of the tool CI is associated with the tool CI number and stored in the storage device 120. When the number of a tool CI is designated by the user via the input / output device 130, the acquisition unit 210 acquires the tool data, thereby acquiring the radius of the tool CI registered in advance from the storage device 120. The radius of the tool CI will hereinafter be referred to as the third radius.

[0045] The workpiece data includes the position of the thick-walled cylinder CP, the position of the through-hole HE, a first radius R1 of the cylindrical surface SS of the thick-walled cylinder CP, a second radius R2 of the imaginary cylinder CS that forms the shape of the through-hole HE, the arrangement angle of the thick-walled cylinder CP, the penetration angle of the through-hole HE, and the eccentricity distance f described above. The thick-walled cylinder CP and the through-hole HE are each located at a predetermined position. The position of the thick-walled cylinder CP will be referred to as the second position below. The position of the through-hole HE will be referred to as the third position below. The second position of the thick-walled cylinder CP and the third position of the through-hole HE are expressed in a machine coordinate system predefined for the machine tool 10 or a workpiece coordinate system based on the workpiece.

[0046] The arrangement angle of the thick-walled cylinder CP is the angle formed by the first direction, in which the first central axis A1 of the thick-walled cylinder CP extends, with respect to the Y-axis. In this embodiment, as described above, the first direction coincides with the direction of the Y-axis. Therefore, the value of the arrangement angle of the thick-walled cylinder CP acquired by the acquisition unit 210 as a value indicating the first direction is 0°.

[0047] The penetration angle of the through hole HE is the angle formed by the second direction, in which the second central axis A2 of the cylinder CS forming the shape of the through hole HE extends, with respect to the Z axis. In this embodiment, as described above, the second direction coincides with the direction of the Z axis. Therefore, the value of the penetration angle of the through hole HE acquired by the acquisition unit 210 as a value indicating the second direction is 0°.

[0048] The optional data includes a cutting depth Q and a tolerance TA. The tool CI cuts the ridge line RL with a predetermined machining width W at a first position C corresponding to the machining point P, thereby removing the burr BR. By cutting the ridge line RL, a machining surface with the predetermined machining width W is formed between the cylindrical peripheral surface SS of the thick-walled cylinder CP and the peripheral wall surface SW of the through hole HE. In other words, the distance between both ends of the machining surface in the machining width direction (a first distance described later) is equal to the predetermined machining width W.

[0049] FIG. 7A is a diagram for explaining the relationship between the cutting depth Q and the predetermined machining width W. As is clear from FIG. 7A, the predetermined machining width W is expressed by equation (1) using the cutting depth Q. The predetermined machining width W is specified by a user input using this cutting depth Q. The cutting depth Q is a value that is 1 / √2 times the predetermined machining width W. When the cutting depth Q is specified by the user via the input / output device 130, the acquisition unit 210 acquires the cutting depth Q to acquire the predetermined machining width W.

number

[0050] The tolerance amount TA indicates a value related to the machining path RP when the tool CI cuts the ridge line RL while moving along the machining path RP according to the ridge line RL. When the first positions C of the tool CI corresponding to all (an infinite number of) machining target points P on the ridge line RL are calculated, the ideal trajectory TR of the tool CI is determined. However, in reality, the first positions C of the tool CI corresponding to a finite number of machining target points P are calculated. Therefore, the machining path RP formed by linearly connecting the finite number of machining target points P does not match the ideal trajectory TR.

[0051] The tolerance TA is specified by a user as an upper limit of the error of the machining path RP with respect to the ideal trajectory TR. When the tolerance TA is specified, a plurality of machining points P on the ridge line RL are determined by the determination unit 220 of the calculation device 110 based on the tolerance TA.

[0052] 7B and 7C are diagrams for explaining the tolerance TA. A plurality of machining target points P are determined so that the error RG of the machining path RP relative to the ideal trajectory TR of the tool CI is within the tolerance TA. In the example shown in FIG. 7B, a value TA1 is specified as the tolerance TA by user input. In this case, four machining target points P101, P102, P103, and P104 are determined so that the error RG is equal to or less than the value TA1.

[0053] In the example shown in Fig. 7C, a value TA2 smaller than the value TA1 is specified as the tolerance amount TA by user input. In this case, eight machining target points P201, P202, P203, P204, P205, P206, P207, and P208 are determined so that the error RG is equal to or smaller than the value TA2. The number of machining target points P in Fig. 7C is greater than the number of machining target points P in Fig. 7B. The machining path RP in Fig. 7C is closer to the ideal trajectory TR than the machining path RP in Fig. 7B.

[0054] When the tolerance TA is set to a small value, the upper limit of the error RG becomes smaller, and the machining path RP becomes closer to the ideal trajectory TR. On the other hand, when the tolerance TA is set to a small value, the number of machining points P increases, and the calculation load on the calculation device 110 becomes heavier. Therefore, the user inputs the tolerance TA to the calculation device 110 via the input / output device 130, taking into consideration how close the machining path RP should be to the ideal trajectory TR and the calculation load. If the user does not input the tolerance TA, a predetermined default setting value for the tolerance TA is used.

[0055] The tangent to the ridge line RL of the through hole HE will be referred to as the first tangent line B1 below. FIG. 8 is a diagram illustrating the through hole HE that penetrates the thick-walled cylinder CP in the shape of a cylinder CS, and the first tangent line B1 to the ridge line RL of the through hole HE. FIG. 8 also shows the cylindrical circumferential surface SS of the thick-walled cylinder CP. When burrs BR generated on the inner circumferential surface SN of the thick-walled cylinder CP are removed, the inner circumferential surface SN corresponds to the cylindrical circumferential surface SS. When burrs BR generated on the outer circumferential surface ST of the thick-walled cylinder CP are removed, the outer circumferential surface ST corresponds to the cylindrical circumferential surface SS. The central axis of the cylindrical circumferential surface SS coincides with the first central axis A1 of the thick-walled cylinder CP. In other words, the direction in which the central axis of the cylindrical circumferential surface SS extends is the first direction, which is the direction of the Y-axis.

[0056] FIG. 8 shows the imaginary cylinder CS intersecting with the cylindrical circumferential surface SS of the thick-walled cylinder CP. This cylinder CS passes through the through hole HE. The ridge line RL of the through hole HE is shown as the intersection line between the cylindrical circumferential surface SS of the thick-walled cylinder CP and the cylinder CS. As described above, the direction in which the second central axis A2 of the cylinder CS extends is the second direction, which is the direction of the Z axis. The second direction in which the second central axis A2 extends is perpendicular to the first direction in which the first central axis A1 extends.

[0057] FIG. 8 shows a first tangent B1 to the ridge line RL of the through hole HE at a machining target point P on the ridge line RL that is cut by the tool CI. The tool CI has a spherical cutting surface. If the line connecting the center of the sphere and the machining target point P is perpendicular to the first tangent B1, overcutting will not occur when the tool CI cuts the ridge line RL. In this case, the center position of the sphere that forms the cutting surface is defined as the first position C of the tool CI. In other words, the first position C of the tool CI is on a vertical plane VP that is perpendicular to the first tangent B1 to the ridge line RL and includes the machining target point P.

[0058] 9 is a diagram illustrating a vertical plane VP perpendicular to the first tangent B1 of the ridge line RL of the through hole HE, and a first ellipse E1 and a second ellipse E2 formed on the vertical plane VP. The vertical plane VP is determined based on the position of the machining target point P on the ridge line RL and the machining target data acquired by the acquisition unit 210 of the calculation device 110. The position of the machining target point P on the ridge line RL is hereinafter referred to as the fourth position. An intersection curve IL is obtained by the intersection of the vertical plane VP with the cylinder circumferential surface SS and the cylinder CS.

[0059] The intersection curve IL includes a portion of the contours of the first ellipse E1 and the second ellipse E2 formed on the vertical plane VP. The first ellipse E1 is formed as the intersection line between the vertical plane VP and the cylinder circumferential surface SS. The second ellipse E2 is formed as the intersection line between the vertical plane VP and the cylinder CS. On the vertical plane VP, the fourth position of the machining point P is on the contour line of the first ellipse E1 and on the contour line of the second ellipse E2.

[0060] The solid portion between the outer peripheral surface ST and inner peripheral surface SN of the thick-walled cylinder CP is hereinafter referred to as the cylindrical shell of the thick-walled cylinder CP. The area outside the first ellipse E1 corresponds to the area outside the cylindrical peripheral surface SS. When the cylindrical peripheral surface SS corresponds to the inner peripheral surface SN of the thick-walled cylinder CP, the cylindrical shell of the thick-walled cylinder CP is included in the area outside the first ellipse E1 at the fourth position of the machining point P on the ridge line RL and in its vicinity. The area inside the first ellipse E1 corresponds to the area inside the cylindrical peripheral surface SS. When the cylindrical peripheral surface SS corresponds to the outer peripheral surface ST of the thick-walled cylinder CP, the cylindrical shell of the thick-walled cylinder CP is included in the area inside the first ellipse E1 at the fourth position of the machining point P on the ridge line RL and in its vicinity.

[0061] The area inside the second ellipse E2 corresponds to the area inside the cylinder CS. At and near the fourth position of the processing target point P on the ridge line RL, the through hole HE is included in the area inside the second ellipse E2. The section from the processing target point P on the ridge line RL to a position a predetermined distance along the contour of the second ellipse E2 is formed by the peripheral wall surface SW that forms the through hole HE.

[0062] The tangent to the first ellipse E1 at the machining point P will be referred to as the second tangent B2 below. The tangent to the second ellipse E2 at the machining point P will be referred to as the third tangent B3 below. Fig. 10 is a diagram showing the positional relationship between the second tangent B2 to the first ellipse E1, the third tangent B3 to the second ellipse E2, and a tool CI that removes a burr BR generated on the inner surface SN of a thick-walled cylinder CP.

[0063] The direction in which the major axis of the second ellipse E2 extends is the direction of the T-axis, and the direction perpendicular to the T-axis (the direction in which the minor axis of the second ellipse E2 extends) is the direction of the S-axis. If the processing point P is the origin, the positive direction of the S-axis is the direction from the origin to the outside of the second ellipse E2. If the processing point P is the origin, the positive direction of the T-axis is the direction from the origin to the outside of the first ellipse E1. The vertical plane VP is a plane formed by the S-axis (horizontal axis) and T-axis (vertical axis), which are perpendicular to each other.

[0064] At the machining point P on the ridge line RL, the cylindrical shell of the thick-walled cylinder CP having the through hole HE is included in an area that is outside the first ellipse E1 and outside the second ellipse E2. The contour line of the first ellipse E1 extending from the machining point P corresponds to the inner surface SN of the thick-walled cylinder CP. The contour line of the second ellipse E2 extending from the machining point P corresponds to the peripheral wall surface SW that forms the through hole HE.

[0065] When the tool CI cuts the ridgeline RL at a first position C corresponding to the machining target point P on the ridgeline RL, a machining surface of a predetermined machining width W is formed between the inner peripheral surface SN of the thick-walled cylinder CP and the peripheral wall surface SW of the through-hole HE. Figure 10 shows the first and second endpoints G1 and G2 on a vertical plane VP corresponding to both ends of the machining surface in the machining width direction. The linear distance between the first and second endpoints G1 and G2 is hereinafter referred to as the "first distance." The first distance is equal to the predetermined machining width W. The first endpoint G1 is actually located on the contour of the first ellipse E1. However, because the first endpoint G1 is located near the machining target point P, the first endpoint G1 can be considered to be located on the second tangent B2 of the first ellipse E1 at the machining target point P.

[0066] The second end point G2 is actually located on the contour of the second ellipse E2. However, because the second end point G2 is located near the processing target point P, the second end point G2 can be considered to be located on the third tangent B3 to the second ellipse E2 at the processing target point P. In this embodiment, to simplify the calculation, the first end point G1 is considered to be located on the second tangent B2, and the second end point G2 is considered to be located on the third tangent B3.

[0067] The first ellipse E1 can be formulated using the two-dimensional coordinate values ​​of the center K1 on the vertical plane VP and a parametric representation based on the eccentric anomaly angle using the major and minor axes. For example, the second tangent B2 of the first ellipse E1 at the target point P can be calculated using the formulation of the first ellipse E1. The second ellipse E2 can be formulated using the two-dimensional coordinate values ​​of the center K2 on the vertical plane VP and a parametric representation based on the eccentric anomaly angle using the major and minor axes. For example, the third tangent B3 of the second ellipse E2 at the target point P can be calculated using the formulation of the second ellipse E2. The third tangent B3 is parallel to the T-axis.

[0068] 10, the cross section of the sphere that forms the cutting surface of the tool CI is represented on a vertical plane VP as a circle that passes through a first end point G1 and a second end point G2 that correspond to both ends of the above-mentioned cutting surface in the cutting width direction. The length from the first position C of the tool CI, which is shown as the center of the circle, to the first end point G1 and the length from the first position C of the tool CI to the second end point G2 are both equal to the third radius D of the tool CI.

[0069] 11 is a diagram for explaining that a first position C of the tool CI corresponding to a machining target point P on the ridge line RL of the through hole HE is calculated based on a predetermined machining width W. As described above, the first end point G1 and the second end point G2 correspond to both ends in the machining width direction of the machining surface formed by the tool CI cutting the ridge line RL at the first position C corresponding to the machining target point P.

[0070] In this embodiment, the length from the machining target point P to the first end point G1 on the second tangent line B2 is equal to the length from the machining target point P to the second end point G2 on the third tangent line B3. In this case, it is possible to relatively prevent burrs from being generated due to the tool CI cutting the ridge line RL. Note that the length from the machining target point P to the first end point G1 and the length from the machining target point P to the second end point G2 do not necessarily have to be equal.

[0071] As described above, the length from the first position C to the first end point G1 of the tool CI and the length from the first position C to the second end point G2 of the tool CI are both equal to the third radius D of the tool CI. In this embodiment, the first position C of the tool CI is also located on the bisector DL ​​that bisects the angle formed by the second tangent B2 and the third tangent B3, with the machining point P as the starting point. A line segment SL connecting the first end point G1 and the second end point G2 intersects with the bisector DL ​​at an intersection M. This intersection M is the midpoint of the line segment SL.

[0072] As described above, the first distance between the first end point G1 and the second end point G2 is equal to the predetermined machining width W. In other words, the length of the line segment SL is equal to the predetermined machining width W. The length from the intersection point M, which is also the midpoint of the line segment SL, to the first end point G1 is 1 / 2 of the predetermined machining width W. The distance between the intersection point M and the machining target point P is hereinafter referred to as the second distance L. The angle formed by the second tangent B2 and the third tangent B3, starting from the machining target point P, is hereinafter referred to as the first angle β. The first angle β is a value greater than or equal to 90° and less than 180° (90°≦β<180°).

[0073] The second distance L is calculated based on the first angle β and the predetermined machining width W. According to equation (1), the predetermined machining width W can be expressed by replacing it with the cutting depth Q. Therefore, the first calculation unit 230 of the calculation device 110 calculates the second distance L using equation (2).

number

[0074] The first calculation unit 230 calculates the length CL from the first position C of the tool CI to the machining target point P based on the second distance L, the third radius D of the tool CI, and the cutting depth Q corresponding to the predetermined machining width W. The length CL from the first position C of the tool CI to the machining target point P is calculated using equation (3).

number

[0075] As described above, in this embodiment, the first position C of the tool CI is located on the bisector DL. The first calculation unit 230 calculates the first position C on the vertical plane VP based on the bisector DL ​​and the length CL from the first position C to the machining target point P. Based on the calculation result and the definition of the vertical plane VP, it is possible to calculate the first position C of the tool CI in the coordinate space defined by the X-axis, Y-axis, and Z-axis. The first position C of the tool CI is calculated for each of the multiple machining target points P. Each machining target point P is closest to the first position C of the tool CI on the ridge line RL.

[0076] 12 is a diagram showing the positional relationship between the second tangent B2 to the first ellipse E1, the third tangent B3 to the second ellipse E2, and the tool CI that removes the burr BR generated on the outer peripheral surface ST of the thick-walled cylinder CP. At the machining target point P on the ridge line RL, the cylindrical shell of the thick-walled cylinder CP is included in the area inside the first ellipse E1 and outside the second ellipse E2. The contour line of the first ellipse E1 extending from the machining target point P corresponds to the outer peripheral surface ST of the thick-walled cylinder CP. The contour line of the second ellipse E2 extending from the machining target point P corresponds to the peripheral wall surface SW that forms the through hole HE.

[0077] When the tool CI cuts the ridge line RL at a first position C corresponding to the machining target point P on the ridge line RL, a machining surface of a predetermined machining width W is formed between the outer peripheral surface ST of the thick-walled cylinder CP and the peripheral wall surface SW of the through hole HE. A first end point G1 and a second end point G2 corresponding to both ends of the machining surface in the machining width direction are shown in Figure 12. The first distance, which is the linear distance between the first end point G1 and the second end point G2, is equal to the predetermined machining width W. The first end point G1 is actually located on the contour line of the first ellipse E1. However, because the first end point G1 is located near the machining target point P, the first end point G1 can be considered to be located on the second tangent B2 to the first ellipse E1 at the machining target point P.

[0078] The second end point G2 is actually located on the contour of the second ellipse E2. However, because the second end point G2 is located near the processing target point P, the second end point G2 can be considered to be located on the third tangent B3 to the second ellipse E2 at the processing target point P. In this embodiment, to simplify the calculation, the first end point G1 is considered to be located on the second tangent B2, and the second end point G2 is considered to be located on the third tangent B3.

[0079] 12, the cross section of the sphere that forms the cutting surface of the tool CI is represented on a vertical plane VP as a circle that passes through a first end point G1 and a second end point G2 that correspond to both ends of the above-mentioned cutting surface in the cutting width direction. The length from the first position C of the tool CI, which is shown as the center of the circle, to the first end point G1 and the length from the first position C of the tool CI to the second end point G2 are both equal to the third radius D of the tool CI.

[0080] 13 is a diagram for explaining that a first position C of the tool CI corresponding to a machining target point P on the ridge line RL of the through hole HE is calculated based on a predetermined machining width W. As described above, the first end point G1 and the second end point G2 correspond to both ends in the machining width direction of the machining surface formed by the tool CI cutting the ridge line RL at the first position C corresponding to the machining target point P.

[0081] In this embodiment, the length from the machining target point P to the first end point G1 on the second tangent line B2 is equal to the length from the machining target point P to the second end point G2 on the third tangent line B3. In this case, it is possible to relatively prevent burrs from being generated due to the tool CI cutting the ridge line RL. Note that the length from the machining target point P to the first end point G1 and the length from the machining target point P to the second end point G2 do not necessarily have to be equal.

[0082] As described above, the length from the first position C to the first end point G1 of the tool CI and the length from the first position C to the second end point G2 of the tool CI are both equal to the third radius D of the tool CI. In this embodiment, the first position C of the tool CI is also located on the bisector DL ​​that bisects the angle formed by the second tangent B2 and the third tangent B3, with the machining point P as the starting point. A line segment SL connecting the first end point G1 and the second end point G2 intersects with the bisector DL ​​at an intersection M. This intersection M is the midpoint of the line segment SL.

[0083] The length of the line segment SL is equal to the predetermined machining width W. The length from the intersection point M, which is also the midpoint of the line segment SL, to the first end point G1 is 1 / 2 of the predetermined machining width W. The second distance L between the intersection point M and the machining target point P is calculated based on the predetermined machining width W and the first angle β formed by the second tangent line B2 and the third tangent line B3, with the machining target point P as the starting point. The first calculation unit 230 of the calculation device 110 calculates the second distance L using equation (2).

[0084] The first calculation unit 230 calculates the length CL from the first position C of the tool CI to the machining target point P based on the second distance L, the third radius D of the tool CI, and the cutting depth Q corresponding to the predetermined machining width W. The length CL from the first position C of the tool CI to the machining target point P is calculated using equation (3). The first calculation unit 230 calculates the first position C on the vertical plane VP based on the bisector DL ​​and the length CL from the first position C to the machining target point P. Based on the calculation result and the definition of the vertical plane VP, it is possible to calculate the first position C of the tool CI in the coordinate space defined by the X-axis, Y-axis, and Z-axis. The first position C of the tool CI is calculated for each of the multiple machining target points P. Each machining target point P is closest to the first position C of the tool CI on the ridge line RL.

[0085] 14 is a flowchart showing a processing procedure executed by control device 30 of machine tool 10. This processing procedure is performed, for example, by arithmetic device 110 of control device 30 executing a calculation program. When this processing procedure starts, in step S102, acquisition unit 210 of arithmetic device 110 acquires machining object data from the user or storage device 120.

[0086] The machining object data includes a second position of the thick-walled cylinder CP, a third position of the through-hole HE, a first radius R1 of the cylindrical surface SS of the thick-walled cylinder CP, a second radius R2 of an imaginary cylinder CS forming the shape of the through-hole HE, an arrangement angle of the thick-walled cylinder CP, a penetration angle of the through-hole HE, and an eccentricity distance f. The arrangement angle of the thick-walled cylinder CP corresponds to a first direction in which a first central axis A1 of the thick-walled cylinder CP extends. The value of the penetration angle of the through-hole HE is 0°.

[0087] In step S104, the acquisition unit 210 acquires tool data based on the tool CI number designated by the user from the storage device 120. As the tool data, the third radius D of the tool CI is associated with the tool CI number.

[0088] In step S106, the acquisition unit 210 acquires optional data. The optional data includes a cutting depth Q and a tolerance TA. When the cutting depth Q is specified, a predetermined machining width W is determined. When the tolerance TA is specified, in step S108, the determination unit 220 of the calculation device 110 determines a plurality of machining points P on the ridge line RL.

[0089] In step S110, the first calculation unit 230 of the calculation device 110 calculates a first tangent B1 to the ridge line RL at each machining point P. In step S112, the first calculation unit 230 calculates a second tangent B2 at each machining point P to a first ellipse E1 formed by a vertical plane VP perpendicular to the first tangent B1 and the cylindrical circumferential surface SS. In step S114, the first calculation unit 230 calculates a third tangent B3 at each machining point P to a second ellipse E2 formed by the vertical plane VP and an imaginary cylinder CS.

[0090] In step S116, the first calculation unit 230 calculates a bisector DL ​​that bisects the angle formed by the second tangent line B2 and the third tangent line B3, with the processing object point P as the starting point, based on the processing object data.

[0091] In step S118, the first calculation unit 230 determines a line segment SL connecting a first end point G1 on the second tangent line B2 and a second end point G2 on the third tangent line B3. A first distance between the first end point G1 and the second end point G2 of the line segment SL is equal to the predetermined machining width W. The first calculation unit 230 calculates a second distance L between the machining target point P and an intersection M where the line segment SL intersects with the bisector DL ​​at a right angle. The second distance L is calculated based on the first angle β formed by the second tangent line B2 and the third tangent line B3 and the predetermined machining width W.

[0092] In step S120, the first calculation unit 230 calculates a first position C of the tool CI corresponding to each machining point P based on the second distance L, the third radius D of the tool CI, and the predetermined machining width W. In step S122, the first calculation unit 230 determines whether or not the first positions C of the tool CI corresponding to all of the multiple machining points P determined in step S108 have been calculated.

[0093] If the result in step S122 is NO, the process returns to step S110. If the result in step S122 is YES, the process proceeds to step S124. In step S124, the machining control unit 250 of the calculation device 110 causes the tool CI to cut the ridge line RL at the first position C corresponding to each machining point P. When the processing in step S124 is completed, the process ends.

[0094] Fig. 15 is a diagram illustrating a computer program product of an arithmetic program for causing the arithmetic device 110 of the control device 30 to execute the processing procedure shown in Fig. 14. The arithmetic program described above is recorded on a recording medium 310 such as a CD-ROM or a USB memory, and is supplied to the control device 30.

[0095] The calculation program may be recorded on a data signal 330 flowing over a communication network 320 such as the Internet, and supplied to the control device 30 by a server 340. The server 340 loads the calculation program stored in a storage device (not shown) onto a carrier wave as the data signal 330. The server 340 provides the calculation program by transmitting the data signal 330 to the control device 30 via the communication network 320. In this way, the calculation program is supplied as a computer-readable computer program product such as the recording medium 310 or the data signal 330.

[0096] [Variations] The above embodiment may be modified as follows.

[0097] (Variation 1) In the above embodiment, the first position C of the tool CI at the machining point P is calculated using the first angle β formed by the second tangent B2 to the first ellipse E1 and the third tangent B3 to the second ellipse E2 at the machining point P. However, the first position C of the tool CI at the machining point P may also be calculated using coordinate values ​​based on a coordinate system consisting of the S axis and the T axis on the vertical plane VP.

[0098] Fig. 16 is a diagram illustrating an example of the configuration of control device 30 of machine tool 10. Compared to Fig. 2A, a second calculation unit 440 is added to calculation device 110. When calculation device 110 executes a calculation program stored in storage device 120, it realizes acquisition unit 210, determination unit 220, first calculation unit 230, second calculation unit 440, and machining control unit 250. At least some of acquisition unit 210, determination unit 220, first calculation unit 230, second calculation unit 440, and machining control unit 250 may be realized by integrated circuits such as ASICs and FPGAs, or electronic circuits including discrete devices.

[0099] The second calculation unit 440 calculates the first and second basis vectors on the vertical plane VP based on the processing object data. The first and second basis vectors will be described in detail later.

[0100] FIG. 17A shows the angle γ formed by the perpendicular line from the machining target point P on the ridge line RL of the through hole HE to the first central axis A1 of the thick-walled cylinder CP relative to the X-axis. FIG. 17A shows the cylindrical circumferential surface SS of the thick-walled cylinder CP shown in FIGS. 3B, 8, and 9, and the imaginary cylinder CS that forms the shape of the through hole HE, viewed from the negative direction of the Y-axis. The fourth position of the machining target point P is on the ridge line RL, which is determined based on the machining target data. The second central axis A2 of the cylinder CS is offset from the first central axis A1 of the thick-walled cylinder CP by an eccentric distance f in the direction of the X-axis.

[0101] Of the cylindrical circumferential surface SS shown in Figure 17A, the area included inside the cylinder CS corresponds to the through hole HE. Since the machining target point P is on the ridge line RL of the through hole HE, the machining target point P is located within this area. The length of the perpendicular line from the machining target point P to the first central axis A1 is equal to the length of the first radius R1 of the cylindrical circumferential surface SS. The fourth position of the machining target point P is expressed by a parameter called γ, the angle that the perpendicular line makes with the X-axis. Taking the eccentricity distance f into consideration, the X-component Xp of the three-dimensional coordinate value in XYZ space that represents the fourth position of the machining target point P is expressed by equation (4) using the position O on the X-axis of the second central axis A2 as the reference. Xp=R1·cosγ-f (4)

[0102] The angle formed by the perpendicular line from the machining target point P on the ridge line RL of the through hole HE to the second central axis A2 with respect to the X axis is hereinafter referred to as the third angle. FIG. 17B is a diagram showing the third angle φ formed by the perpendicular line from the machining target point P on the ridge line RL of the through hole HE to the second central axis A2 of the cylinder CS that forms the shape of the through hole HE with respect to the X axis, and the first basis vector e1. FIG. 17B shows a view of the imaginary cylinder CS shown in FIGS. 3B, 8, and 9, viewed from the positive direction of the Z axis. Because the machining target point P is on the ridge line RL of the through hole HE, the third angle φ is greater than 0° and less than or equal to 360° (0°<φ≦360°). However, the upper limit of the third angle φ may be less than 360°.

[0103] The length of the perpendicular line from the machining point P to the second central axis A2 is equal to the length of the second radius R2 of the cylinder CS. The fourth position of the machining point P is expressed by a parameter called the third angle φ that the perpendicular line makes with the X axis. The X component Xp of the three-dimensional coordinate value in the XYZ space that represents the fourth position of the machining point P is shown in equation (5) with the position of the second central axis A2 as the reference. Based on equations (4) and (5), equation (6) is obtained. Xp=R2 cosφ (5) R1·cosγ-f=R2·cosφ (6)

[0104] 17B shows the first tangent B1 to the ridge line RL at the machining point P. A vector that is perpendicular to this first tangent B1 and passes through the machining point P is included in the vertical plane VP described above. A vector that starts at the machining point P, is perpendicular to the second central axis A2, and forms a third angle φ with the X-axis is defined as the first basis vector e1 of the vertical plane VP. The first basis vector e1 is perpendicular to the first tangent B1 and is parallel to the S-axis described above as the horizontal axis of the vertical plane VP. When the magnitude of the first basis vector e1 is 1, the three-dimensional coordinate value of the first basis vector e1 in the XYZ space is expressed by equation (7) using the third angle φ as a parameter.

number

[0105] The three-dimensional coordinate values ​​of the second basis vector e2, which has the machining target point P as its starting point on the vertical plane VP and is perpendicular to the first basis vector e1, are shown in equation (8) as a vector of magnitude 1 based on equations (6) and (7). The direction in which the second basis vector e2 extends is from the machining target point P toward the outside of the thick-walled cylinder CP. The second basis vector e2 is perpendicular to the first tangent B1 and is parallel to the T-axis, which is the longitudinal axis of the vertical plane VP. The second calculation unit 440 of the calculation device 110 calculates the first basis vector e1 and the second basis vector e2 for each of the multiple machining target points P using equations (7) and (8) using the machining target data.

number

[0106] FIG. 18 shows the positional relationship between the second tangent line B2, the third tangent line B3, and the tool CI used to remove the burr BR generated on the inner surface SN of the thick-walled cylinder CP, as well as the first and second basis vectors e1 and e2. In addition to the contents of FIG. 10, FIG. 18 also shows the first and second basis vectors e1 and e2. As described above, the first basis vector e1 is parallel to the S-axis, and the second basis vector e2 is perpendicular to the first basis vector e1. Therefore, in FIG. 18, the second basis vector e2 is depicted overlapping with the third tangent line B3, which is parallel to the T-axis.

[0107] FIG. 19 is a diagram illustrating how a first position C of the tool CI corresponding to a machining target point P on the ridge line RL of the through hole HE is calculated based on a predetermined machining width W. As in the above embodiment, in this modified example, the first position C of the tool CI is also located on a bisector DL ​​that bisects the angle formed by the second tangent line B2 and the third tangent line B3, with the machining target point P as the starting point. In addition to the contents of FIG. 11, FIG. 19 also shows a first basis vector e1, a second basis vector e2, and a direction vector u parallel to the bisector DL. The direction vector u is a vector with a magnitude of 1 that starts at the machining target point P on the vertical plane VP and points in the fourth direction along which the bisector DL ​​extends.

[0108] The angle that the second tangent B2 makes with the first base vector e1 on the vertical plane VP is hereinafter referred to as the second angle α. As described above, the second tangent B2 is calculated based on the formulation of the first ellipse E1. Therefore, the second angle α that the second tangent B2 makes with the first base vector e1 on the vertical plane VP is shown in equation (9). The first calculation unit 230 of the calculation device 110 calculates the second angle α corresponding to the third angle φ for each processing point P using equation (9).

number

[0109] The first calculation unit 230 calculates the direction vector u based on the equation (10) using the second angle α described above.

number

[0110] As described above, the first distance between the first end point G1 on the second tangent B2 and the second end point G2 on the third tangent B3 (the length of the line segment SL connecting the first end point G1 and the second end point G2) is equal to the predetermined machining width W. The first calculation unit 230 calculates the second distance L between the machining point P and the intersection M where the line segment SL intersects with the bisector DL ​​at right angles on the vertical plane VP, based on equation (11) using the second angle α.

number

[0111] The first calculation unit 230 calculates the first position C of the tool CI based on the direction vector u, the second distance L, the third radius D of the tool CI, and the cutting depth Q corresponding to the predetermined machining width W. The two-dimensional coordinate values ​​(Sc, Tc) of the first position C of the tool CI on the vertical plane VP are calculated using equation (12) when the machining target point P is set as the origin of the ST plane. Furthermore, based on equation (12) and the definition of the vertical plane VP, the first position C of the tool CI in the coordinate space defined by the X-axis, Y-axis, and Z-axis can be calculated.

number

[0112] Fig. 20 is a diagram showing the positional relationship between the second tangent line B2, the third tangent line B3, and the tool CI that removes the burr BR generated on the outer peripheral surface ST of the thick-walled cylinder CP, as well as the first basis vector e1 and the second basis vector e2. In addition to the contents of Fig. 12, Fig. 20 also shows the first basis vector e1 and the second basis vector e2. In Fig. 20, the second basis vector e2 is drawn so that it is connected to the third tangent line B3 that is parallel to the T axis.

[0113] FIG. 21 is a diagram illustrating how a first position C of the tool CI corresponding to a machining target point P on the ridge line RL of the through hole HE is calculated based on a predetermined machining width W. As in the above embodiment, in this modification, the first position C of the tool CI is also located on a bisector DL ​​that bisects the angle formed by the second tangent line B2 and the third tangent line B3, starting from the machining target point P. In addition to the contents of FIG. 13, FIG. 21 also shows a first basis vector e1, a second basis vector e2, and a direction vector u parallel to the bisector DL. The first calculation unit 230 of the calculation device 110 calculates a second angle α corresponding to the third angle φ for each machining target point P using equation (9).

[0114] The first calculation unit 230 calculates the direction vector u based on the equation (13) using the second angle α described above.

number

[0115] The first calculation unit 230 calculates a second distance L between the processing point P and an intersection M where the line segment SL intersects the bisector DL ​​at right angles on the vertical plane VP, based on equation (14) using the second angle α.

number

[0116] The first calculation unit 230 calculates the first position C of the tool CI based on the direction vector u, the second distance L, the third radius D of the tool CI, and the cutting depth Q corresponding to the predetermined machining width W. The two-dimensional coordinate values ​​(Sc, Tc) of the first position C of the tool CI on the vertical plane VP are calculated using equation (12) when the machining target point P is set as the origin of the ST plane. Furthermore, based on equation (12) and the definition of the vertical plane VP, the first position C of the tool CI in the coordinate space defined by the X-axis, Y-axis, and Z-axis can be calculated.

[0117] Figure 22 is a flowchart showing a processing procedure executed by control device 30 of machine tool 10. This processing procedure is performed, for example, by arithmetic device 110 of control device 30 executing an arithmetic program. Some of the reference numerals assigned to the steps of the processing procedure shown in Figure 22 match the reference numerals assigned to the steps of the control processing shown in Figure 14, indicating that the same processing is performed. Explanation of these processing steps will be omitted.

[0118] When the processing of step S110 described above is completed, in step S200, the second calculation unit 440 of the calculation device 110 calculates the first basis vector e1 and the second basis vector e2 based on the processing object data. When the processing of step S200 is completed, the processing of step S112 described above is performed.

[0119] Upon completion of the processing of step S114 described above, in step S210, the first calculation unit 230 of the calculation device 110 calculates a direction vector u pointing in the fourth direction in which the bisector DL ​​extends. In step S220, the first calculation unit 230 determines a line segment SL connecting a first endpoint G1 on the second tangent B2 and a second endpoint G2 on the third tangent B3. The first distance between the first endpoint G1 and the second endpoint G2 of the line segment SL is equal to the predetermined machining width W. The first calculation unit 230 calculates a second distance L between the machining target point P and an intersection M where the line segment SL intersects the bisector DL ​​at a right angle, using the second angle α and the predetermined machining width W.

[0120] In step S230, the first calculation unit 230 calculates the first position C of the tool CI based on the direction vector u, the second distance L, the third radius D of the tool CI, and the predetermined machining width W. When the processing of step S230 is completed, the processing of step S122 described above is performed. Note that a computer program product of a calculation program for causing the calculation device 110 of the control device 30 to execute this processing procedure is exemplified in FIG. 15.

[0121] (Variation 2) In the above embodiment, the workpiece is a thick-walled cylinder CP, but the workpiece is not limited to a thick-walled cylinder CP. The workpiece may have a rectangular parallelepiped outer surface and a cylindrical hollow portion. A manifold block, for example, is used as a workpiece having such a shape. FIG. 23 is a diagram illustrating a manifold block MB used as the workpiece. In FIG. 23, the manifold block MB is arranged on the XY plane.

[0122] The hollow portion of the manifold block MB is cylindrical, and therefore the inner peripheral surface SN of the manifold block MB forms a cylindrical peripheral surface SS. A central axis passing through the center of the cylindrical peripheral surface SS is a first central axis A1 of the manifold block MB. In this modification, the first direction in which the first central axis A1 of the manifold block MB extends is the direction of the Y-axis.

[0123] A through hole HE having the shape of a cylinder CS that penetrates the manifold block MB from its outer peripheral surface to its inner peripheral surface SN is defined by the peripheral wall surface SW. A second direction in which a second central axis A2 of the cylinder CS that defines the through hole HE extends is the direction of the Z axis. In this modification, the tool CI removes burrs BR formed on the inner peripheral surface SN of the manifold block MB.

[0124] The ridge line RL that forms the edge of the through hole HE is the ridge line RLN. The ridge line RLN is formed by the peripheral wall surface SW of the through hole HE and the inner peripheral surface SN of the manifold block MB. The first calculation unit 230 calculates a first position C of the tool CI that cuts the ridge line RLN of the manifold block MB with a predetermined machining width W, in the same manner as when the workpiece is a thick-walled cylinder CP.

[0125] (Variation 3) In the above embodiment, when the through hole HE penetrating the thick-walled cylinder CP is viewed from directly above the through hole HE, the through hole HE has a circular shape. However, instead of a circular through hole HE, an elongated through hole HE may be provided in the thick-walled cylinder CP. FIG. 24 is a diagram illustrating a thick-walled cylinder CP and an elongated through hole HE penetrating the thick-walled cylinder CP. In FIG. 24, an elongated through hole HE is formed in the thick-walled cylinder CP instead of the circular through hole HE shown in FIG. 3A.

[0126] The ridge line RL of the through hole HE includes two arc-shaped sections that form an arc when viewed from directly above the through hole HE, and two linear sections that are parallel to the first direction (the direction of the Y axis). As described above, the first direction is the direction in which the first central axis A1 of the thick-walled cylinder CP extends. The two arc-shaped sections constitute the two corners (both ends) of the ridge line RL of the through hole HE, which has an elongated hole shape. These two arc-shaped sections are connected to form the ridge line RL via the two linear sections.

[0127] The elongated through hole HE penetrates the thick-walled cylinder CP from its outer peripheral surface ST to its inner peripheral surface SN in the shape of an imaginary cylinder CB1 shown in FIG. 24. The cylinder CB1 includes two parallel imaginary cylinders CS1 and CS2 at both corners (both ends) of the cylinder CB1. The second direction in which the central axis A21 of the cylinder CS1 and the central axis A22 of the cylinder CS2 extend is the direction of the Z axis. Therefore, the central axes A21 and A22 are parallel to each other. When the through hole HE is viewed from directly above the through hole HE along the Z axis, the through hole HE has an elongated shape corresponding to the cylinder CB1. The through hole HE is formed by a peripheral wall surface SW.

[0128] FIG. 25 is a schematic diagram of a through hole HE having an elongated hole shape. FIG. 25 shows a thick-walled cylinder CP having an elongated through hole HE as viewed from the positive direction of the Z axis outside the thick-walled cylinder CP. FIG. 25 shows two imaginary cylinders CS1 and CS2, each with a circular bottom surface, in the elongated through hole HE. The radius of cylinder CS1 and the radius of cylinder CS2 are equal. The radii of cylinders CS1 and CS2 are both a second radius R2.

[0129] The ridge line RL of the elongated through hole HE includes an arc-shaped section RL1, a linear section RL2, an arc-shaped section RL3, and a linear section RL4. The linear sections RL2 and RL4 are parallel to the Y axis. The arc-shaped section RL1 corresponds to half of the circumference forming the side surface of the cylinder CS1. The arc-shaped section RL3 corresponds to half of the circumference forming the side surface of the cylinder CS2. The areas where the two cylinders CS1 and CS2 each pass through the through hole HE are included in both corners (both ends) of the through hole HE.

[0130] In Fig. 25, a processing point P1 is shown at a position on the ridge line RL of the through hole HE where the linear section RL4 and the arc-shaped section RL1 join together. In Fig. 25, a processing point P2 is shown at a position on the ridge line RL of the through hole HE where the arc-shaped section RL1 and the linear section RL2 join together.

[0131] In Fig. 25, a processing target point P3 is shown at a position on the ridge line RL of the through hole HE where the linear section RL2 and the arc-shaped section RL3 join together. In Fig. 25, a processing target point P4 is shown at a position on the ridge line RL of the through hole HE where the arc-shaped section RL3 and the linear section RL4 join together.

[0132] As described above, the arc-shaped section RL1 from the machining target point P1 to the machining target point P2 corresponds to the imaginary cylinder CS1. Therefore, the first calculation unit 230 calculates the first position C of the tool CI that cuts the arc-shaped section RL1 of the ridge line RL with a predetermined machining width W, in the same way as in the case of the circular through-hole HE that penetrates the thick-walled cylinder CP shown in Figures 5A and 5B.

[0133] As described above, the arc-shaped section RL3 from the machining target point P3 to the machining target point P4 corresponds to the imaginary cylinder CS2. Therefore, the first calculation unit 230 calculates the first position C of the tool CI that cuts the arc-shaped section RL3 of the ridge line RL with a predetermined machining width W, in the same way as in the case of the circular through-hole HE that penetrates the thick-walled cylinder CP shown in Figures 5A and 5B.

[0134] That is, the first calculation unit 230 calculates a first position C of the tool CI in the arc-shaped sections RL1 and RL3 of the ridgeline RL based on the second tangent B2 to the first ellipse E1, the third tangent B3 to the second ellipse E2, a predetermined machining width W, and a third radius D of the tool CI. The tool CI, which is placed at the first position C corresponding to the machining target point P in the arc-shaped sections RL1 and RL3, cuts the ridgeline RL with the predetermined machining width W.

[0135] In a three-dimensional coordinate space defined by the X-axis, Y-axis, and Z-axis, the three-dimensional coordinate values ​​of a first position C of the tool CI that cuts the ridge line RL at the machining target point P2 with a predetermined machining width W are set to (Xc2, Yc2, Zc2). The machining target point P2 is included in the above-mentioned arc-shaped section RL1 of the ridge line RL. The three-dimensional coordinate values ​​of a first position C of the tool CI that cuts the ridge line RL at the machining target point P3 with a predetermined machining width W are set to (Xc3, Yc3, Zc3). The machining target point P3 is included in the above-mentioned arc-shaped section RL3 of the ridge line RL.

[0136] 25, the linear section RL2 of the ridge line RL extends in the direction of the Y axis and connects between the machining target points P2 and P3. That is, the machining target point P2 is located at a position obtained by moving the machining target point P3 in the direction of the Y axis by the length of the linear section RL2 of the ridge line RL. The first position C of the tool CI corresponding to the machining target point P2 is also located at a position obtained by moving the first position C of the tool CI corresponding to the machining target point P3 in the direction of the Y axis by the length of the linear section RL2.

[0137] Therefore, the difference between the Y component Yc2 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P2 and the Y component Yc3 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P3 corresponds to the length of the linear section RL2 of the ridge line RL. In this way, the Y components Yc2 and Yc3 are determined.

[0138] Note that the X component Xc2 and Z component Zc2 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P2 are equal to the X component Xc3 and Z component Zc3 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P3. For any machining target point P on the linear section RL2 of the ridge line RL, the X component and Z component of the three-dimensional coordinate value representing the first position C of the tool CI are both constant values, and the Y component changes linearly.

[0139] In a three-dimensional coordinate space defined by the X-axis, Y-axis, and Z-axis, the three-dimensional coordinate values ​​of a first position C of the tool CI that cuts the ridge line RL at the machining target point P4 with a predetermined machining width W are set to (Xc4, Yc4, Zc4). The machining target point P4 is included in the above-mentioned arc-shaped section RL3 of the ridge line RL. The three-dimensional coordinate values ​​of a first position C of the tool CI that cuts the ridge line RL at the machining target point P1 with a predetermined machining width W are set to (Xc1, Yc1, Zc1). The machining target point P1 is included in the above-mentioned arc-shaped section RL1 of the ridge line RL.

[0140] 25, the linear section RL4 of the ridge line RL extends in the direction of the Y axis and connects the machining target points P4 and P1. That is, the machining target point P1 is located at a position obtained by moving the machining target point P4 in the direction of the Y axis by the length of the linear section RL4 of the ridge line RL. The first position C of the tool CI corresponding to the machining target point P1 is also located at a position obtained by moving the first position C of the tool CI corresponding to the machining target point P4 in the direction of the Y axis by the length of the linear section RL4.

[0141] Therefore, the difference between the Y component Yc1 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P1 and the Y component Yc4 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P4 corresponds to the length of the linear section RL4 of the ridge line RL. In this way, the Y components Yc1 and Yc4 are determined.

[0142] Note that the X component Xc1 and Z component Zc1 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P1 are respectively equal to the X component Xc4 and Z component Zc4 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P4. For any machining target point P on the linear section RL4 of the ridge line RL, the X component and Z component of the three-dimensional coordinate value representing the first position C of the tool CI are both constant values, and the Y component changes linearly.

[0143] The first position C of the tool CI corresponding to the machining target points P1 and P2 in the arc-shaped section RL1 is calculated as described above. The first position C of the tool CI corresponding to the machining target points P3 and P4 in the arc-shaped section RL3 is also calculated as described above. The first calculation unit 230 calculates the first position C of the tool CI in the linear sections RL2 and RL4 of the ridge line RL based on the first positions C of the tool CI corresponding to the machining target points P1, P2, P3, and P4, respectively, and the machining target data. As described above, the machining target data is acquired by the acquisition unit 210. The tool CI placed at the first position C corresponding to the machining target point P in the linear sections RL2 and RL4 cuts the ridge line RL with a predetermined machining width W.

[0144] (Variation 4) In the third modification, when the through hole HE is viewed from directly above the through hole HE that penetrates the thick-walled cylinder CP, the through hole HE has an elongated hole shape. However, the through hole HE may also have a rounded rectangular shape. FIG. 26 is a diagram illustrating a thick-walled cylinder CP and a through hole HE that penetrates the thick-walled cylinder CP and has a rounded rectangular shape. The ridge line RL of the through hole HE includes four arc-shaped sections that form an arc when viewed from directly above the through hole HE, two linear sections that are parallel to the first direction (the direction of the Y-axis), and two linear sections that are parallel to the direction of the X-axis.

[0145] As described above, the first direction is the direction in which the first central axis A1 of the thick-walled cylinder CP extends. The X-axis direction is perpendicular to the Y-axis direction (first direction) and the Z-axis direction (second direction). The four arc-shaped sections form the four corners of the through hole HE, which has a rounded rectangular shape, on the ridge line RL. These four arc-shaped sections are connected to form the ridge line RL via the four linear sections described above.

[0146] The through hole HE, which has a rounded rectangular shape, penetrates the thick-walled cylinder CP from the outer peripheral surface ST to the inner peripheral surface SN of the thick-walled cylinder CP in the shape of an imaginary cylinder CB2 shown in Fig. 26. The cylinder CB2 includes four parallel imaginary cylinders CS10, CS20, CS30, and CS40 at the four corners of the cylinder CB2, respectively.

[0147] The second direction in which the central axis A210 of the cylinder CS10, the central axis A220 of the cylinder CS20, the central axis A230 of the cylinder CS30, and the central axis A240 of the cylinder CS40 extend is the direction of the Z axis. Therefore, the central axes A210, A220, A230, and A240 are parallel to one another. When the through hole HE is viewed from directly above the through hole HE along the Z axis, the through hole HE has a rounded rectangular shape corresponding to the column CB2. The through hole HE is formed by a peripheral wall surface SW.

[0148] FIG. 27 is a schematic diagram showing a through hole HE having a rounded rectangular shape. FIG. 27 shows a thick-walled cylinder CP having a through hole HE having a rounded rectangular shape, viewed from the positive direction of the Z axis outside the thick-walled cylinder CP. FIG. 27 shows four imaginary cylinders CS10, CS20, CS30, and CS40, each with a circular bottom, in the through hole HE having a rounded rectangular shape. The radii of cylinder CS10, CS20, CS30, and CS40 are all equal. The radii of cylinders CS10, CS20, CS30, and CS40 are all second radii R2.

[0149] The ridge line RL of the rounded rectangular through hole HE includes an arc-shaped section RL10, a linear section RL20, an arc-shaped section RL30, a linear section RL40, an arc-shaped section RL50, a linear section RL60, an arc-shaped section RL70, and a linear section RL80. The linear sections RL20 and RL60 are parallel to the X-axis. The linear sections RL40 and RL80 are parallel to the Y-axis.

[0150] The arc-shaped section RL10 corresponds to 1 / 4 of the circumference forming the side surface of the cylinder CS10. The arc-shaped section RL30 corresponds to 1 / 4 of the circumference forming the side surface of the cylinder CS20. The arc-shaped section RL50 corresponds to 1 / 4 of the circumference forming the side surface of the cylinder CS30. The arc-shaped section RL70 corresponds to 1 / 4 of the circumference forming the side surface of the cylinder CS40. The areas where the four cylinders CS10, CS20, CS30, and CS40 each pass through the through hole HE are encompassed by the four corners of the through hole HE.

[0151] In Fig. 27, a processing target point P10 is shown at a position on the ridge line RL of the through hole HE where a linear section RL80 and an arc-shaped section RL10 are connected to each other. In Fig. 27, a processing target point P20 is shown at a position on the ridge line RL of the through hole HE where a circular section RL10 and a linear section RL20 are connected to each other.

[0152] In Fig. 27, a processing point P30 is shown at a position on the ridge line RL of the through hole HE where a linear section RL20 and an arc-shaped section RL30 are connected to each other. In Fig. 27, a processing point P40 is shown at a position on the ridge line RL of the through hole HE where a circular section RL30 and a linear section RL40 are connected to each other.

[0153] In Fig. 27, a processing point P50 is shown at a position on the ridge line RL of the through hole HE where a linear section RL40 and an arc-shaped section RL50 are connected to each other. In Fig. 27, a processing point P60 is shown at a position on the ridge line RL of the through hole HE where a circular section RL50 and a linear section RL60 are connected to each other.

[0154] In Fig. 27, a processing point P70 is shown at a position on the ridge line RL of the through hole HE where a linear section RL60 and an arc-shaped section RL70 are connected to each other. In Fig. 27, a processing point P80 is shown at a position on the ridge line RL of the through hole HE where a circular-shaped section RL70 and a linear section RL80 are connected to each other.

[0155] As described above, the arc-shaped section RL10 from the machining target point P10 to the machining target point P20 corresponds to the virtual cylinder CS10. Therefore, the first calculation unit 230 calculates the first position C of the tool CI that cuts the arc-shaped section RL10 of the ridge line RL with a predetermined machining width W, in the same way as in the case of the circular through-hole HE that penetrates the thick-walled cylinder CP shown in Figures 5A and 5B.

[0156] As described above, the arc-shaped section RL30 from the machining target point P30 to the machining target point P40 corresponds to the virtual cylinder CS20. Therefore, the first calculation unit 230 calculates the first position C of the tool CI that cuts the arc-shaped section RL30 of the ridge line RL with a predetermined machining width W, in the same way as in the case of the circular through-hole HE that penetrates the thick-walled cylinder CP shown in Figures 5A and 5B.

[0157] As described above, the arc-shaped section RL50 from the machining target point P50 to the machining target point P60 corresponds to the virtual cylinder CS30. Therefore, the first calculation unit 230 calculates the first position C of the tool CI that cuts the arc-shaped section RL50 of the ridge line RL with a predetermined machining width W, in the same way as in the case of the circular through-hole HE that penetrates the thick-walled cylinder CP shown in Figures 5A and 5B.

[0158] As described above, the arc-shaped section RL70 from the machining target point P70 to the machining target point P80 corresponds to the virtual cylinder CS40. Therefore, the first calculation unit 230 calculates the first position C of the tool CI that cuts the arc-shaped section RL70 of the ridge line RL with a predetermined machining width W, in the same way as in the case of the circular through-hole HE that penetrates the thick-walled cylinder CP shown in Figures 5A and 5B.

[0159] That is, the first calculation unit 230 calculates a first position C of the tool CI in the arc-shaped sections RL10, RL30, RL50, and RL70 of the ridgeline RL based on the second tangent B2 to the first ellipse E1, the third tangent B3 to the second ellipse E2, a predetermined machining width W, and a third radius D of the tool CI. The tool CI, which is placed at the first position C corresponding to the machining target point P in the arc-shaped sections RL10, RL30, RL50, and RL70, cuts the ridgeline RL with the predetermined machining width W.

[0160] As shown in FIG. 27, a linear section RL40 of the ridge line RL extends in the direction of the Y-axis and connects between machining target points P40 and P50. That is, the machining target point P40 is located at a position obtained by moving the machining target point P50 in the direction of the Y-axis by the length of the linear section RL40 of the ridge line RL. A first position C of the tool CI corresponding to the machining target point P40 is also located at a position obtained by moving the first position C of the tool CI corresponding to the machining target point P50 in the direction of the Y-axis by the length of the linear section RL40. Therefore, the first calculation unit 230 calculates the first position C of the tool CI that cuts the linear section RL40 of the ridge line RL with a predetermined machining width W, in the same manner as in the case of the elongated through hole HE that penetrates the thick-walled cylinder CP shown in FIGS. 24 and 25.

[0161] As shown in FIG. 27, a linear section RL80 of the ridge line RL extends in the direction of the Y-axis and connects between machining target points P80 and P10. That is, the machining target point P10 is located at a position obtained by moving the machining target point P80 in the direction of the Y-axis by the length of the linear section RL80 of the ridge line RL. A first position C of the tool CI corresponding to the machining target point P10 is also located at a position obtained by moving the first position C of the tool CI corresponding to the machining target point P80 in the direction of the Y-axis by the length of the linear section RL80. Therefore, the first calculation unit 230 calculates the first position C of the tool CI that cuts the linear section RL80 of the ridge line RL with a predetermined machining width W, in the same manner as in the case of the elongated through hole HE that penetrates the thick-walled cylinder CP shown in FIGS. 24 and 25.

[0162] The first position C of the tool CI corresponding to the machining target point P10 in the arc-shaped section RL10 is calculated as described above. The first position C of the tool CI corresponding to the machining target point P40 in the arc-shaped section RL30 is also calculated as described above. The first position C of the tool CI corresponding to the machining target point P50 in the arc-shaped section RL50 is also calculated as described above. The first position C of the tool CI corresponding to the machining target point P80 in the arc-shaped section RL70 is also calculated as described above.

[0163] The first calculation unit 230 calculates the first position C of the tool CI in the linear sections RL40 and RL80 of the ridge line RL based on the first position C of the tool CI corresponding to the machining target points P10, P40, P50, and P80, respectively, and the machining target data. As described above, the machining target data is acquired by the acquisition unit 210. The tool CI, placed at the first position C corresponding to the machining target point P in the linear sections RL40 and RL80, cuts the ridge line RL with a predetermined machining width W.

[0164] In a three-dimensional coordinate space defined by the X-axis, Y-axis, and Z-axis, the three-dimensional coordinate values ​​of a first position C of the tool CI that cuts the ridge line RL at the machining target point P20 with a predetermined machining width W are set to (Xc20, Yc20, Zc20). The machining target point P20 is included in the above-mentioned arc-shaped section RL10 of the ridge line RL. The three-dimensional coordinate values ​​of a first position C of the tool CI that cuts the ridge line RL at the machining target point P30 with a predetermined machining width W are set to (Xc30, Yc30, Zc30). The machining target point P30 is included in the above-mentioned arc-shaped section RL30 of the ridge line RL.

[0165] 27, a linear section RL20 of the ridge line RL extends in the direction of the X-axis and connects between the machining target points P20 and P30. That is, the machining target point P30 is located at a position obtained by moving the machining target point P20 in the direction of the X-axis by the length of the linear section RL20 of the ridge line RL. The first position C of the tool CI corresponding to the machining target point P30 is also located at a position obtained by moving the first position C of the tool CI corresponding to the machining target point P20 in the direction of the X-axis by the length of the linear section RL20.

[0166] Therefore, the difference between the X component Xc30 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P30 and the X component Xc20 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P20 corresponds to the length of the linear section RL20 of the ridge line RL. In this way, the X components Xc20 and Xc30 are determined.

[0167] In addition, the Y component Yc20 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining point P20 is equal to the Y component Yc30 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining point P30.

[0168] Machining points P20 and P30 are located on the cylindrical circumferential surface SS of the thick-walled cylinder CP. As shown in FIG. 17A, when viewed from the Y axis, the cylindrical circumferential surface SS is represented by a circle of a first radius R1 centered on the position of the first central axis A1 of the thick-walled cylinder CP on the XZ plane. A linear section RL20 when viewed from the positive direction of the Z axis appears as part of an arc of this circle when viewed from the negative direction of the Y axis. In FIG. 17A, if the two-dimensional coordinate value of position O on the X axis of the second central axis A2 is (0, 0), the coordinate value of the center position of the circle representing the cylindrical circumferential surface SS is (-f, 0).

[0169] Fig. 28 is a diagram illustrating the positional relationship between the first position C of the tool CI and the first central axis A1 of the thick-walled cylinder CP. Fig. 28 shows a view of the portion beyond the cut surface of the thick-walled cylinder CP cut by a plane perpendicular to the Y axis (a plane parallel to the XZ plane), viewed from the negative direction of the Y axis. The tool CI removes burrs BR by cutting the ridge line RL including the machining target point P with a predetermined cutting width. Of the ridge line RL to be cut, the section RL20 from the machining target point P20 to the machining target point P30 is included in the circle representing the cylinder circumferential surface SS described above.

[0170] Therefore, the first position C of the tool CI that cuts the ridge line RL in the section RL20 from the machining target point P20 to the machining target point P30 is on the arc of the circle CC of radius R3 whose center is the same as the center position (-f, 0) of the circle representing the cylinder circumferential surface SS described above. The center position (-f, 0) of the circle CC is the position on the XZ plane of the first central axis A1 of the thick-walled cylinder CP. The circle CC is expressed on the XZ plane by equation (15). The X and Z components of the three-dimensional coordinate values ​​that represent the first position C of the tool CI that cuts the ridge line RL in the section RL20 from the machining target point P20 to the machining target point P30 satisfy equation (15). (X+f) 2 +Z 2 =R3 2 ···(15)

[0171] The X-component Xc20 and Z-component Zc20 of the three-dimensional coordinate value representing the first position C20 of the tool CI corresponding to the machining point P20 also satisfy equation (15). The X-component Xc30 and Z-component Zc30 of the three-dimensional coordinate value representing the first position C30 of the tool CI corresponding to the machining point P30 also satisfy equation (15). Therefore, the radius R3 of the circle CC described above is obtained by equation (16). The radius R3 of the circle CC is equal to the distance between the first position C20 of the tool CI corresponding to the machining point P20 and the first central axis A1 of the thick-walled cylinder CP. The radius R3 of the circle CC is also equal to the distance between the first position C30 of the tool CI corresponding to the machining point P30 and the first central axis A1 of the thick-walled cylinder CP.

number

[0172] The Z components Zc20 and Zc30 are obtained by substituting the above-mentioned X components Xc20 and Xc30 of the three-dimensional coordinate values ​​representing the first position C of the tool CI corresponding to the machining points P20 and P30 into the variable X in equation (15).

[0173] At any machining point P on section RL20 of ridgeline RL, when the X component of the three-dimensional coordinate value representing the first position C of the tool CI changes, the Y component remains constant, and the Z component changes according to the X component according to equation (15). Note that FIG. 28 shows an example in which the ridgeline RL (RLN) forming the edge of the through hole HE is cut by the tool CI to remove a burr BR generated on the inner surface SN of the thick-walled cylinder CP. However, the same applies to the case in which the ridgeline RL forming the edge of the through hole HE is cut by the tool CI to remove a burr BR generated on the outer surface ST of the thick-walled cylinder CP.

[0174] In a three-dimensional coordinate space defined by the X-axis, Y-axis, and Z-axis, the three-dimensional coordinate values ​​of a first position C of the tool CI that cuts the ridge line RL at a machining target point P60 with a predetermined machining width W are set to (Xc60, Yc60, Zc60). The machining target point P60 is included in the above-mentioned arc-shaped section RL50 of the ridge line RL. The three-dimensional coordinate values ​​of a first position C of the tool CI that cuts the ridge line RL at a machining target point P70 with a predetermined machining width W are set to (Xc70, Yc70, Zc70). The machining target point P70 is included in the above-mentioned arc-shaped section RL70 of the ridge line RL.

[0175] 27, a linear section RL60 of the ridge line RL extends in the direction of the X-axis and connects between the machining target points P60 and P70. That is, the machining target point P60 is located at a position obtained by moving the machining target point P70 in the direction of the X-axis by the length of the linear section RL60 of the ridge line RL. The first position C of the tool CI corresponding to the machining target point P60 is also located at a position obtained by moving the first position C of the tool CI corresponding to the machining target point P70 in the direction of the X-axis by the length of the linear section RL60.

[0176] Therefore, the difference between the X component Xc60 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P60 and the X component Xc70 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining target point P70 corresponds to the length of the linear section RL60 of the ridge line RL. In this way, the X components Xc60 and Xc70 are determined.

[0177] In addition, the Y component Yc60 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining point P60 is equal to the Y component Yc70 of the three-dimensional coordinate value representing the first position C of the tool CI corresponding to the machining point P70.

[0178] Machining target points P60 and P70 are located on the cylindrical circumferential surface SS of the thick-walled cylinder CP. Therefore, equation (15) holds, in which Z components Zc60 and Zc70 of the three-dimensional coordinate values ​​representing the first position C of the tool CI corresponding to the machining target points P60 and P70 are variable Z. By substituting the above-mentioned X components Xc60 and Xc70 of the three-dimensional coordinate values ​​representing the first position C of the tool CI corresponding to the machining target points P60 and P70 into variable X in equation (15), each of the Z components Zc60 and Zc70 can be determined.

[0179] At any machining point P on section RL60 of the ridge line RL, when the X component of the three-dimensional coordinate value representing the first position C of the tool CI changes, the Y component becomes a constant value, and the Z component changes depending on the X component according to equation (15).

[0180] The first position C of the tool CI corresponding to the machining target point P20 in the arc-shaped section RL20 is calculated as described above. The first position C of the tool CI corresponding to the machining target point P30 in the arc-shaped section RL30 is also calculated as described above. The first position C of the tool CI corresponding to the machining target point P60 in the arc-shaped section RL50 is also calculated as described above. The first position C of the tool CI corresponding to the machining target point P70 in the arc-shaped section RL70 is also calculated as described above.

[0181] The first calculation unit 230 calculates the first position C of the tool CI in the linear sections RL20 and RL60 of the ridge line RL based on the first position C of the tool CI corresponding to the machining target points P20, P30, P60, and P70, respectively, and the machining target data. As described above, the machining target data is acquired by the acquisition unit 210. The tool CI, placed at the first position C corresponding to the machining target point P in the linear sections RL20 and RL60, cuts the ridge line RL with a predetermined machining width W.

[0182] (Variation 5) The above-described embodiments and modifications may be combined in any manner.

[0183] [Inventions Obtained from the Embodiments] The invention that can be understood from the above-described embodiment and modifications will be described below.

[0184] (1) In a workpiece (CP, MB) in which at least one of an outer peripheral surface (ST) and an inner peripheral surface (SN) is formed as a cylindrical peripheral surface (SS), from one of the outer peripheral surface and the inner peripheral surface to the other, a peripheral wall surface (S) is formed in the shape of a cylinder (CS, CS1, CS2, CS10, CS20, CS30, CS40) or a columnar body (CB1, CB2) in which a plurality of parallel cylinders are included at the corners, forming a through hole (HE) penetrating the workpiece. A calculation device (110) calculates a first position (C) of a tool (CI) that cuts a ridgeline (RL) formed by the cylindrical circumferential surface and the first center axis (A1) of the workpiece with a predetermined machining width (W), the calculation device (110) calculates a first position (C) of a tool (CI) that cuts a ridgeline (RL) formed by the cylindrical circumferential surface and the first center axis (A1) of the workpiece with a predetermined machining width (W), the calculation device (110) calculates a first position (C) of a tool (CI) that cuts a ridgeline (RL) formed by the cylindrical circumferential surface and the first center axis (A1) of the workpiece with a predetermined machining width (W), the calculation device (110) calculates a second ...). an acquisition unit (210) that acquires machining object data including an eccentric distance (f) of a second central axis (A2, A21, A22, A210, A220, A230, A240) of a cylinder from the first central axis and a third radius (D) of the tool; a plane (VP) that includes a machining object point (P) on the ridge line and is perpendicular to a first tangent (B1) to the ridge line at the machining object point (P), and acquires a fourth position of the machining object point and a third radius (D) of the tool; and a first calculation unit (230) that calculates the first position of the tool that cuts the ridgeline including the point to be machined based on a second tangent (B2) at the point to be machined of a first ellipse (E1) formed by the plane and the cylindrical circumferential surface, which is determined based on the above, a third tangent (B3) at the point to be machined of the second ellipse (E2) formed by the cylinder and the plane, the predetermined machining width, and the third radius of the tool. This makes it possible to accurately calculate the position of the tool that achieves stable cutting to remove burrs.

[0185] (2) The arithmetic device may include a determination unit (220) that, when a tolerance (TA) for a machining path when the tool cuts the ridgeline while moving along a machining path (RP) corresponding to the ridgeline is specified by a user, determines the plurality of machining points on the ridgeline based on the tolerance, and the first arithmetic unit may calculate the first position of the tool corresponding to each of the plurality of machining points. This makes it possible to achieve cutting that takes into account the balance between the required accuracy of cutting and the calculation performance of the arithmetic device.

[0186] (3) The first calculation unit may calculate, based on the machining object data, a bisector (DL) that bisects the angle formed by the second tangent and the third tangent, with the machining point as its starting point, and calculate, based on the machining object data, a second distance (L) between the machining object point and an intersection (M) where a line segment (SL) that connects a first end point (G1) on the second tangent and a second end point (G2) on the third tangent, and where a first distance between the first end point and the second end point is equal to the predetermined machining width, intersects the bisector at a right angle, based on the first angle (β) of the angle and the predetermined machining width, and calculate the first position of the tool based on the bisector, the second distance, the third radius of the tool, and the predetermined machining width. This makes it possible to accurately calculate the position of the tool through simple calculations.

[0187] (4) The calculation device further includes a second calculation unit (440) that calculates, based on the processing object data, a first basis vector (e1) that has the processing object point as a starting point on the plane and is perpendicular to the second central axis line, and a second basis vector (e2) that has the processing object point as a starting point on the plane and is perpendicular to the first basis vector, and the first direction is the direction of the Y axis, the second direction is the direction of the Z axis that is perpendicular to the direction of the Y axis, and a third direction is the direction of the Y axis that is perpendicular to both the Y axis and the Z axis. When the direction of the workpiece is the direction of the X-axis, the first calculation unit calculates a second angle α that the second tangent makes with the first base vector on the plane based on equation (9) using the first radius R1 of the workpiece, the second radius R2 of the cylinder, and the eccentricity distance f, in accordance with a third angle φ that a perpendicular from the workpiece point to the second central axis makes with the X-axis, and calculates a second angle α that the second tangent makes with the first base vector on the plane based on equations (10) and (13) using the second angle α. A direction vector u facing a fourth direction along which a bisector (DL) that bisects the angle formed by the second tangent and the third tangent extends is calculated, and a line segment (SL) that connects a first end point (G1) on the second tangent and a second end point (G2) on the third tangent on the plane, and a first distance between the first end point and the second end point is equal to the predetermined machining width, is calculated based on equations (11) and (14) that use the second angle α and the predetermined machining width √2·Q, and a line segment (SL) that connects a first end point (G1) on the second tangent and a second end point (G2) on the third tangent on the plane and whose first distance between the first end point and the second end point is equal to the predetermined machining width is calculated. ) and the machining point, calculate coordinate values ​​(Sc, Tc) representing the first position of the tool on the plane based on equation (12) using the direction vector u, the second distance L, the third radius D of the tool, and the predetermined machining width √2·Q, and calculate the first position of the tool in a coordinate space defined by the X-axis, the Y-axis, and the Z-axis based on the coordinate values, the first basis vector, and the second basis vector. This makes it possible to accurately calculate the position of the tool with simple calculations.

[0188] (5) The through hole may have the shape of a cylinder that penetrates the workpiece, and when viewed from directly above the through hole, the through hole may have a circular shape corresponding to the cylinder. This allows for accurate calculation of the position of a tool that cuts the ridgeline of the circular through hole.

[0189] (6) The through hole may have a cylindrical shape that includes two parallel cylinders at both corners and penetrates the workpiece, the through hole having an elongated hole shape corresponding to the cylinder when viewed from directly above the through hole, the ridge line of the through hole when viewed from directly above the through hole includes two arc-shaped sections (RL1, RL3) corresponding to the two cylinders respectively and two straight sections (RL2, RL4) parallel to the first direction, and the first calculation unit may calculate the first position of the tool corresponding to the point to be machined in the two arc-shaped sections of the ridge line based on the second tangent, the third tangent, the specified machining width, and the third radius of the tool, and the first calculation unit may calculate the first position of the tool corresponding to the point to be machined in the two straight sections of the ridge line based on the first position of the tool in the two arc-shaped sections and the machining object data. This makes it possible to accurately calculate the position of the tool that cuts the ridgeline of the elongated through-hole.

[0190] (7) The through hole has a columnar shape that includes four parallel cylinders at each of its four corners, and penetrates the workpiece. When viewed from directly above the through hole, the through hole has a rounded rectangular shape corresponding to the columnar shape. When viewed from directly above the through hole, the ridge line of the through hole is divided into four arc-shaped sections (RL10, RL30, RL50, RL70) that respectively correspond to the four cylinders, two linear sections (RL40, RL80) that are parallel to the first direction, and two other linear sections that are parallel to a direction perpendicular to the first direction and the second direction. The present invention may further include a method for cutting a through hole having a rounded rectangular shape, the method comprising: calculating a first position of the tool corresponding to the point to be machined in the four arc-shaped sections of the ridgeline based on the second tangent, the third tangent, the predetermined machining width, and the third radius of the tool; and calculating a first position of the tool corresponding to the point to be machined in the two straight-line sections of the ridgeline that are parallel to the first direction and the other two straight-line sections based on the first position of the tool in the four arc-shaped sections and the machining object data. This makes it possible to accurately calculate the position of the tool that cuts the ridgeline of a through hole having a rounded rectangular shape.

[0191] (8) The acquisition unit may acquire the predetermined machining width based on a user input, thereby allowing the user to set the machining width of the machining surface formed on the ridge line to a value required for removing burrs.

[0192] (9) The acquisition unit may acquire the workpiece data, the predetermined machining width, and the third radius of the tool based on a G-code indicating a command for calling a macro program (MP) from a storage device (120), the G-code having as an argument at least one of the predetermined machining width, the workpiece data, and a number associated with the tool, the first calculation unit may read the macro program from the storage device based on the G-code, and the first calculation unit may calculate the first position of the tool by executing the macro program. This improves convenience for users who are accustomed to cutting workpieces using G-code.

[0193] (10) The machine tool (10) includes the arithmetic unit, the tool, and a machining control unit (250) that moves the tool to the first position and causes the tool to cut the ridge line, thereby achieving stable cutting for removing burrs.

[0194] (11) The control device (30) of the machine tool (10) includes the arithmetic unit and a machining control unit (250) that moves the tool to the first position and causes the tool to cut the ridge line, thereby achieving stable cutting to remove burrs.

[0195] (12) The calculation program forms a through hole (HE) penetrating a workpiece (CP, MB) having at least one of an outer peripheral surface (ST) and an inner peripheral surface (SN) formed as a cylindrical peripheral surface (SS) from one of the outer peripheral surface and the inner peripheral surface to the other in the shape of a cylinder (CS, CS1, CS2, CS10, CS20, CS30, CS40) or a pillar (CB1, CB2) having a corner containing a plurality of parallel cylinders. The processing circuit of a calculation device (110) calculates a first position (C) of a tool (CI) that cuts a ridgeline (RL) formed by a peripheral wall surface (SW) of the workpiece and the cylindrical peripheral surface with a predetermined machining width (W), and the processing circuit of the calculation device (110) calculates a second position (C) of the workpiece, a third position of the through hole, a first radius (R1) of the cylindrical peripheral surface of the workpiece, a second radius (R2) of the cylinder, a first direction in which a first central axis (A1) of the workpiece extends, and a second radius (R3) of the cylinder in the first direction. The program executes an acquisition procedure for acquiring machining object data including an eccentricity distance (f) from the first central axis of a second central axis (A2, A21, A22, A210, A220, A230, A240) of the cylinder extending in a second perpendicular direction, and a third radius (D) of the tool; and a calculation procedure for calculating the first position of the tool for cutting the ridge line including the machining point, based on a second tangent (B2) at the machining point to a first ellipse (E1) formed by the plane (VP) and the cylinder circumferential surface and perpendicular to a first tangent (B1) to the ridge line at the machining point (P) on the ridge line, the plane being determined based on a fourth position of the machining point and the machining object data, a third tangent (B3) at the machining point to the second ellipse (E2) formed by the cylinder and the plane, the specified machining width, and the third radius of the tool. This makes it possible to accurately calculate the position of the tool that will achieve stable cutting to remove the burrs. [Explanation of symbols]

[0196] 10...Machine tool 20...Main body 30...Control device 52...Bed 54...Saddle 56...Table 74, 76, 78...Movable part 110...Arithmetic unit 120...Storage device 130...Input / output device 210... Acquisition unit 220... Determination unit 230...first calculation unit 250...processing control unit 310...recording medium 320...communication network 330...Data signal 340...Server 440…Second calculation section

Claims

1. A computing device that computes a first position of a tool that cuts, with a predetermined machining width, a ridgeline formed by a peripheral wall surface that forms a through hole penetrating the workpiece, at least one of an outer peripheral surface and an inner peripheral surface being formed as a cylindrical peripheral surface, the ridgeline being formed by the cylindrical peripheral surface and the cylindrical peripheral surface from one of the outer peripheral surface and the inner peripheral surface to the other, the through hole having a cylindrical shape with a plurality of parallel cylinders at each corner; an acquisition unit that acquires processing object data including a second position of the processing object, a third position of the through hole, a first radius of the cylindrical circumferential surface of the processing object, a second radius of the cylinder, a first direction in which a first central axis of the processing object extends, and an eccentricity distance from the first central axis of the second central axis of the cylinder that extends in a second direction perpendicular to the first direction, and a third radius of the tool; a first calculation unit that calculates the first position of the tool that cuts the ridge line including the machining point, based on a second tangent at the machining point to a first ellipse formed by the plane and the cylinder circumferential surface, the plane being perpendicular to a first tangent to the ridge line at the machining point on the ridge line, the plane being determined based on a fourth position of the machining point and the machining object data, a third tangent at the machining point to a second ellipse formed by the cylinder and the plane, the predetermined machining width, and the third radius of the tool; A computing device comprising:

2. 2. The computing device according to claim 1, a determination unit that, when a user specifies a tolerance amount for a machining path when the tool cuts the ridge line while moving along the machining path according to the ridge line, determines the plurality of machining points on the ridge line based on the tolerance amount; The first calculation unit calculates the first position of the tool corresponding to each of the plurality of machining points.

3. 2. The computing device according to claim 1, The first calculation unit Calculating a bisector that bisects the angle formed by the second tangent line and the third tangent line, with the processing object point as a starting point, based on the processing object data; a line segment that connects a first end point on the second tangent line and a second end point on the third tangent line, and a first distance between the first end point and the second end point is equal to the predetermined machining width, is arranged to intersect the bisector at right angles, and the second distance is calculated based on the first angle of the corner and the predetermined machining width; a computing device that calculates the first position of the tool based on the bisector, the second distance, the third radius of the tool, and the predetermined machining width.

4. 2. The computing device according to claim 1, a second calculation unit that calculates, based on the machining object data, a first basis vector that has the machining target point as a start point on the plane and is perpendicular to the second central axis, and a second basis vector that has the machining target point as a start point on the plane and is perpendicular to the first basis vector, The first direction is the direction of the Y axis, The second direction is a Z-axis direction perpendicular to the Y-axis direction, When a third direction perpendicular to both the Y axis and the Z axis is defined as the direction of the X axis, The first calculation unit calculating a second angle α that the second tangent makes with respect to the first base vector on the plane based on the following equation (1) using the first radius R1 of the workpiece, the second radius R2 of the cylinder, and the eccentricity distance f, in accordance with a third angle φ that a perpendicular line from the workpiece point to the second central axis makes with respect to the X-axis; a direction vector u is calculated based on the following formula (2) using the second angle α, the direction vector u being oriented in a fourth direction along which a bisector that bisects the angle formed by the second tangent line and the third tangent line extends, with the processing target point as a start point on the plane; Based on the following formula (3) using the second angle α and the predetermined machining width √2·Q, calculate a second distance L between the machining point and an intersection point of a line segment on the plane that connects a first end point on the second tangent line and a second end point on the third tangent line, and where a first distance between the first end point and the second end point is equal to the predetermined machining width, and the line segment intersects perpendicularly with the bisector; calculating a coordinate value (Sc, Tc) representing the first position of the tool on the plane based on the following equation (4) using the direction vector u, the second distance L, the third radius D of the tool, and the predetermined machining width √2·Q; a computing device that calculates the first position of the tool in a coordinate space defined by the X-axis, the Y-axis, and the Z-axis based on the coordinate values, the first basis vector, and the second basis vector. [Equation 1] [Equation 2] [Equation 3] [Equation 4]

5. The computing device according to any one of claims 1 to 4, the through hole has the cylindrical shape and penetrates the work-piece, A computing device, wherein the through hole has a circular shape corresponding to the cylinder when viewed from directly above the through hole.

6. The computing device according to any one of claims 1 to 4, the through hole has a columnar shape including two parallel cylinders at both corners thereof, and penetrates the work-piece; When the through hole is viewed from directly above the through hole, the through hole has an elongated hole shape corresponding to the column body, the ridge line of the through hole when viewed from directly above the through hole includes two arc-shaped sections corresponding to the two circular cylinders, respectively, and two linear sections parallel to the first direction, the first calculation unit calculates the first position of the tool corresponding to the machining point in the two arc-shaped sections of the ridgeline based on the second tangent, the third tangent, the predetermined machining width, and the third radius of the tool; The first calculation unit calculates the first position of the tool corresponding to the machining target point in the two straight-line sections of the ridge line based on the first position of the tool in the two arc-shaped sections and the machining target data.

7. The computing device according to any one of claims 1 to 4, the through hole has a columnar shape including four parallel cylinders at four corners, and penetrates the work-piece; When the through hole is viewed from directly above the through hole, the through hole has a rounded rectangular shape corresponding to the pillar body, the ridge line of the through hole when viewed from directly above the through hole includes four arc-shaped sections corresponding to the four cylinders, two linear sections parallel to the first direction, and two other linear sections parallel to a direction perpendicular to the first direction and the second direction, the first calculation unit calculates the first position of the tool corresponding to the machining point in the four arc-shaped sections of the ridgeline based on the second tangent, the third tangent, the predetermined machining width, and the third radius of the tool; The first calculation unit calculates the first position of the tool corresponding to the machining target point in the two straight-line sections of the ridge line parallel to the first direction and the other two straight-line sections based on the first position of the tool in the four arc-shaped sections and the machining target data.

8. 2. The computing device according to claim 1, The acquisition unit acquires the predetermined processing width based on a user input.

9. 2. The computing device according to claim 1, the acquisition unit acquires the machining object data, the predetermined machining width, and the third radius of the tool based on the G-code, which indicates a command for calling a macro program from a storage device and which has at least one of the predetermined machining width, the machining object data, and a number associated with the tool as an argument; the first calculation unit reads the macro program from the storage device based on the G-code; The first calculation unit calculates the first position of the tool by executing the macro program.

10. The computing device according to claim 1; The tool; a machining control unit that moves the tool to the first position and causes the tool to cut the ridge line; A machine tool comprising:

11. The computing device according to claim 1; a machining control unit that moves the tool to the first position and causes the tool to cut the ridge line; A control device for a machine tool comprising:

12. A processing circuit included in a computing device that calculates a first position of a tool that cuts, with a predetermined machining width, a ridgeline formed by a peripheral wall surface that forms a through hole penetrating the workpiece, the peripheral wall surface having a cylindrical shape with a corner including a cylinder or a plurality of parallel cylinders extending from one of the outer peripheral surface and the inner peripheral surface to the other, of the workpiece, at least one of which is formed as a cylindrical peripheral surface, and the cylindrical peripheral surface, an acquisition procedure for acquiring workpiece data including a second position of the workpiece, a third position of the through hole, a first radius of the cylindrical circumferential surface of the workpiece, a second radius of the cylinder, a first direction in which a first central axis of the workpiece extends, and an eccentricity distance from the first central axis of the second central axis of the cylinder extending in a second direction perpendicular to the first direction, and a third radius of the tool; a calculation procedure for calculating the first position of the tool for cutting the ridge line including the machining point, based on a second tangent at the machining point to a first ellipse formed by the plane and the cylinder circumferential surface, the plane being perpendicular to a first tangent to the ridge line at the machining point on the ridge line, the plane being determined based on a fourth position of the machining point and the machining object data, a third tangent at the machining point to a second ellipse formed by the cylinder and the plane, the predetermined machining width, and the third radius of the tool; A calculation program for executing the above.

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