Cutting machine and coordinate correction method for cutting machine

Abstract

To improve machining accuracy in a cutting machine in which a machining tool is moved linearly relative to a workpiece in the directions of the X-axis, Y-axis, and Z-axis, and rotated relative to the workpiece around the A-axis.SOLUTION: The coordinate correction method for a cutting machine includes: a first contact process in which a spindle 30 is moved in the X-axis direction to bring a detection tool 31 held by the spindle 30 into contact with a pin 32 held by a clamp 50 and obtain a first contact position; a first movement process in which the clamp 50 is moved a first distance in the Y-axis direction; a second contact process in which, after the first movement process, the spindle 30 is moved in the X-axis direction to bring the detection tool 31 into contact with the pin 32 and obtain a second contact position; and a correction process in which, based on the first contact position, the second contact position, and the first distance, the position coordinates are corrected so that the Y-axis is perpendicular to the A-axis when viewed from the Z-axis.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a cutting machine and a coordinate correction method for the cutting machine. [Background technology]

[0002] Conventionally, as a device for producing, for example, artificial teeth or denture bases, a cutting machine that moves a processing tool linearly relative to a workpiece in the X-axis, Y-axis, and Z-axis directions and rotates the processing tool relative to the workpiece about the A-axis has been known (see, for example, Patent Document 1). Here, the X-axis, Y-axis, and Z-axis are mutually perpendicular, and the A-axis is an axis parallel to the X-axis. Moving the processing tool linearly relative to the workpiece in the X-axis, Y-axis, and Z-axis directions means moving one of the processing tool and the workpiece linearly relative to the other, or moving both of them linearly, in the X-axis, Y-axis, and Z-axis directions, respectively. Rotating the processing tool relative to the workpiece about the A-axis means rotating one or both of the processing tool and the workpiece about the A-axis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-28966 Summary of the Invention [Problem to be solved by the invention]

[0004] In cutting machines, each axis may tilt from its normal direction due to component assembly errors, aging, and other factors. In these cutting machines, the machining tool rotates around the A-axis relative to the workpiece, so tilting an axis perpendicular to the A-axis is likely to result in machining errors. Specifically, as shown in Figure 21, if the Y-axis tilts, moving the machining tool along the Y-axis will result in the tool moving in a direction tilted from the A-axis (see the dashed arrow) instead of the intended direction perpendicular to the A-axis (see the solid arrow). This results in position coordinate errors. Furthermore, position coordinate errors also occur when rotating the workpiece around the A-axis. Therefore, in order to improve machining accuracy in such cutting machines, it is effective to reduce position coordinate errors caused by the tilt of the Y-axis.

[0005] The present invention has been made in view of the above points, and its object is to improve the machining accuracy of a cutting machine in which a machining tool moves linearly relative to a workpiece in the directions of the X-axis, Y-axis, and Z-axis, and rotates relative to the workpiece around the A-axis. [Means for solving the problem]

[0006] The coordinate correction method for a cutting machine disclosed herein is a method for correcting position coordinates of a cutting machine that includes a first holding member that holds a workpiece, a second holding member that holds a processing tool that cuts the workpiece, and a drive device that drives at least one of the first holding member and the second holding member to move the processing tool straight relative to the workpiece in the directions of the X-axis, Y-axis, and Z-axis that are perpendicular to each other, and rotate the workpiece relative to the processing tool around the A-axis that is parallel to the X-axis. The above correction method includes: an attachment process for attaching a correction jig to the first holding member and attaching a detection tool for detecting contact with the correction jig to the second holding member; a first contact process for moving the second holding member relative to the first holding member in the X-axis direction, thereby bringing the detection tool held by the second holding member into contact with the correction jig held by the first holding member, and acquiring a first contact position; a first movement process for moving the second holding member a first distance in the Y-axis direction relative to the first holding member; a second contact process for moving the second holding member relative to the first holding member in the X-axis direction, after the first movement process, thereby bringing the detection tool held by the second holding member into contact with the correction jig held by the first holding member, and acquiring a second contact position; and a correction process for correcting position coordinates based on at least the first contact position, the second contact position, and the first distance, so that the Y-axis is perpendicular to the A-axis when viewed from the Z-axis.

[0007] According to the above correction method, the position coordinates are corrected so that the Y axis is perpendicular to the A axis when viewed from the Z axis, so even if the Y axis is tilted from the correct direction due to an assembly error in the cutting machine parts or deterioration over time, no error in the position coordinates occurs when the processing tool is moved straight in the Y axis direction relative to the workpiece or when the processing tool is rotated around the A axis relative to the workpiece, thereby improving processing accuracy. [Effects of the Invention]

[0008] According to the present invention, the machining accuracy of a cutting machine can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view of a cutting machine according to an embodiment; [Figure 2] FIG. 2 is a front view of the cutting machine with the front cover open. [Figure 3] FIG. 2 is a vertical cross-sectional view of the cutting machine. [Figure 4] FIG. 2 is a perspective view of a clamp, a carriage, and a tool magazine. [Figure 5] FIG. 2 is a block diagram of a control system of the cutting machine. [Figure 6] This is a view of the clamp, carriage, and tool magazine from the Y axis. [Figure 7] FIG. 2 is a perspective view of a workpiece attached to a holder. [Figure 8] FIG. 2 is a functional block diagram of the correction device according to the first embodiment. [Figure 9] FIG. 10 is a diagram illustrating coordinate errors caused by the tilt of the Y-axis. [Figure 10] 4 is a flowchart of a coordinate correction method according to the first embodiment. [Figure 11] 10A and 10B are diagrams illustrating contact between the detection tool and the pin in the first contact process. [Figure 12] 10A and 10B are diagrams illustrating contact between the detection tool and the pin in the second contact process. [Figure 13] FIG. 2 is a diagram illustrating the tilt angle of the Y-axis relative to the perpendicular to the A-axis. [Figure 14] (a) and (b) are diagrams showing contact between the detection tool and the pin when the tip of the pin is flat, and (c) and (d) are diagrams showing contact between the detection tool and the pin when the tip of the pin is curved. [Figure 15] 10 is a flowchart of a coordinate correction method according to the second embodiment. [Figure 16]10A and 10B are diagrams illustrating contact between the detection tool and the pin in the first contact process and the third contact process. [Figure 17] 10A and 10B are diagrams illustrating contact between the detection tool and the pin in the second contact process and the fourth contact process. [Figure 18] FIG. 10 is a functional block diagram of a correction device according to a second embodiment. [Figure 19] FIG. 10 is a diagram showing another example of a correction jig. [Figure 20] FIG. 10 is a diagram showing another example of a correction jig. [Figure 21] FIG. 10 is a diagram illustrating coordinate errors caused by the tilt of the Y-axis. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a cutting machine and a coordinate correction method for the cutting machine will be described with reference to the drawings. The cutting machine described below is a dental cutting machine that produces dental molded products. The cutting machine cuts, for example, crown prostheses, artificial teeth, denture bases, etc.

[0011] FIG. 1 is a perspective view of a cutting machine 10 according to this embodiment. FIG. 2 is a front view of the cutting machine 10 with the front cover 20 open. FIG. 3 is a vertical cross-sectional view of the cutting machine 10. In the following description, when the cutting machine 10 is viewed from the front, the side away from the cutting machine 10 is referred to as the front, and the side approaching the cutting machine 10 is referred to as the rear. Left, right, top, and bottom refer to the left, right, top, and bottom, respectively, when the cutting machine 10 is viewed from the front.

[0012] The cutting machine 10 controls the cutting operation based on coordinates of the X-axis, Y-axis, Z-axis, and A-axis. As shown in FIG. 1, the X-axis, Y-axis, and Z-axis are mutually orthogonal coordinate axes. Here, the X-axis is an axis extending to the right. As shown in FIG. 3, the Y-axis is an axis extending rearward and downward, and the Z-axis is an axis extending upward and rearward. As shown in FIG. 2, the A-axis is an axis parallel to the X-axis. The A-axis is an axis orthogonal to the Y-axis and Z-axis. In this specification, the coordinate of the A-axis refers to the rotation angle around the A-axis. A position related to control in the cutting machine 10 (for example, the position of the tip of the machining tool 6 described below) is specified by four parameters: the coordinate of the X-axis, the coordinate of the Y-axis, the coordinate of the Z-axis, and the rotation angle around the A-axis.

[0013] As shown in FIG. 1, the cutting machine 10 includes a box-shaped case 11. The case 11 includes a case main body 12 and a front cover 20 attached to the case main body 12 so as to be vertically slidable. As shown in FIG. 2, the cutting machine 10 includes a spindle 30 that holds a processing tool 6, a clamp 50, and a drive unit 25 that drives the spindle 30 and the clamp 50. As shown in FIG. 4, the clamp 50 is a member that holds the workpiece 5 and is an example of a "first holding member." As shown in FIG. 3, the spindle 30 holds the processing tool 6 rotatably around the Z axis (the Z axis here includes an axis parallel to the Z axis). The spindle 30 is an example of a "second holding member."

[0014] As shown in Fig. 2, the drive device 25 includes a carriage 38Z to which the spindle 30 is attached, and a carriage 38X to which the carriage 38Z is attached. As shown in Fig. 5, the drive device 25 also includes a Z-axis motor 26Z that moves the carriage 38Z in the Z-axis direction, and an X-axis motor 26X that moves the carriage 38X in the X-axis direction. The Z-axis motor 26Z and the X-axis motor 26X are electrically connected to and controlled by the control device 90.

[0015] As shown in FIG. 2, carriage 38X is slidably supported by a pair of guide shafts 39A extending in the X-axis direction. Carriage 38Z is slidably supported by a pair of guide shafts 39B extending in the Z-axis direction. Guide shafts 39B are fixed to carriage 38X. When carriage 38X moves in the X-axis direction, carriage 38Z also moves in the X-axis direction. Spindle 30 is fixed to carriage 38Z. Therefore, spindle 30 moves in the Z-axis direction in conjunction with the movement of carriage 38Z, and moves in the X-axis direction in conjunction with the movement of carriage 38X.

[0016] As shown in Fig. 6, the drive device 25 includes a rotary shaft 38A extending in the A-axis direction, a rotary motor 26A (see Fig. 5) that rotates the rotary shaft 38A around the A-axis, a carriage 38Y to which the rotary shaft 38A is attached, and a Y-axis motor 26Y (see Fig. 5) that moves the carriage 38Y in the Y-axis direction. The A-axis coincides with the rotation center line of the rotary shaft 38A. The rotary motor 26A and the Y-axis motor 26Y are electrically connected to and controlled by a control device 90.

[0017] When carriage 38Y moves in the Y-axis direction, rotation shaft 38A also moves in the Y-axis direction. Clamp 50 is fixed to rotation shaft 38A. Therefore, clamp 50 moves in the Y-axis direction as carriage 38Y moves, and rotates around the A-axis as rotation shaft 38A rotates.

[0018] As shown in Fig. 4, the carriage 38Y is provided with a tool magazine 40. The tool magazine 40 accommodates a plurality of processing tools 6. The tool magazine 40 is formed with a plurality of (six in this example) holes 42 for accommodating the processing tools 6. The processing tools 6 are inserted into the holes 42 with their tops exposed.

[0019] Although the clamp 50 may be configured to directly hold the workpiece 5, in this embodiment it is configured to indirectly hold the workpiece 5. FIG. 7 is a perspective view of the workpiece 5 attached to the holder 8. The clamp 50 detachably holds the holder 8. The clamp 50 indirectly holds the workpiece 5 via the holder 8. The clamp 50 has multiple insertion holes 50A formed therein (see FIGS. 3 and 6). Here, three insertion holes 50A are aligned in the Y-axis direction. The connecting pins 8B of the holder 8 are inserted into the insertion holes 50A. The connecting pins 8B inserted into the insertion holes 50A are fixed to the clamp 50 by screws 50B.

[0020] The control device 90 is configured by a computer. The control device 90 includes, for example, a central processing unit (CPU) that executes instructions of a control program, a read-only memory (ROM) that stores programs executed by the CPU, a random access memory (RAM) used as a working area for expanding the programs, and a recording medium such as a memory that stores various data. The control device 90 is configured to control cutting processing by, for example, executing a program stored in the ROM. In this embodiment, the control device 90 is disposed inside the case 11 (see FIG. 1). The control device 90 is a dedicated computer built into the cutting machine 10. However, part or all of the control device 90 may be a computer disposed outside the case 11. Part or all of the control device 90 may be a general-purpose computer (e.g., a desktop computer) electrically connected to the cutting machine 10.

[0021] The position of the processing tool 6 relative to the workpiece 5 is specified by the X-axis coordinate, the Y-axis coordinate, the Z-axis coordinate, and the rotation angle around the A-axis. In this embodiment, the processing tool 6 is movable in the X-axis and Z-axis directions, and the workpiece 5 is movable in the Y-axis direction and rotatable around the A-axis. The position of the processing tool 6 can be specified by the X-axis coordinate and the Z-axis coordinate. The position of the workpiece 5 can be specified by the Y-axis coordinate and the rotation angle around the A-axis. Note that the processing tool 6 moves together with the spindle 30, and the workpiece 5 moves together with the clamp 50. Therefore, as positions related to control of the cutting machine 10, the position of the spindle 30 may be used instead of the position of the processing tool 6, and the position of the clamp 50 may be used instead of the position of the workpiece 5.

[0022] The cutting machine 10 is equipped with a correction device 60 that corrects the coordinates of the processing tool 6 and the workpiece 5. The correction device 60 is configured by a computer. FIG. 8 is a functional block diagram of the correction device 60. Part or all of the correction device 60 may be separate from the control device 90, or may be integrated with the control device 90. In this embodiment, the computer that constitutes the control device 90 also serves as the correction device 60. The correction device 60 is equipped with a first contact processing unit 61 that performs a first contact process, a rotation processing unit 63 that performs a rotation process, a movement processing unit 64 that performs a movement process, a second contact processing unit 62 that performs a second contact process, and a correction processing unit 65 that performs a correction process. Each of these processes will be described later.

[0023] The coordinate correction according to this embodiment corrects errors resulting from the tilt of the Y-axis relative to the Z-axis, i.e., coordinate correction in directions parallel to and perpendicular to the A-axis. The Y-axis is essentially an axis perpendicular to the X-axis. However, due to assembly errors or aging of components in the cutting machine 10, the Y-axis may tilt, as exaggeratedly shown in FIG. 9 . When the Y-axis tilts, an error occurs in the angle of the A-axis relative to the Y-axis. That is, the angle of the A-axis relative to the Y-axis deviates from 90 degrees. In the cutting machine 10 according to this embodiment, the clamp 50 rotates around the A-axis and moves linearly in the Y-axis direction. When the Y-axis tilts, for example, the coordinate of the machining position shifts from point P′ in FIG. 9 to point P. Therefore, in this embodiment, the coordinate of the machining position is corrected to reduce errors resulting from the tilt of the Y-axis. For example, a process is performed to correct the coordinate of the machining position from point P to point P′. Here, the processing position is a position where the processing tool 6 cuts the workpiece 5, and where the processing tool 6 and the workpiece 5 come into contact with each other.

[0024] In cutting machine 10, first, the tilt of the Y axis as viewed from the Z axis is detected using a correction jig and a detection tool, and then the coordinates are corrected based on the detected tilt of the Y axis. Next, the coordinate correction method will be described.

[0025] (First embodiment) FIG. 10 is a flowchart of the coordinate correction method according to the first embodiment.

[0026] First, in step S1, a correction jig is attached to the clamp 50, and a detection tool is attached to the spindle 30 (attachment process). In this embodiment, as shown in FIG. 11, a pin 32 is attached to the clamp 50 as a correction jig instead of the workpiece 5. The pin 32 is attached at a position offset in the Y-axis direction from the A-axis (i.e., the rotation center line of the clamp 50). In this embodiment, the pin 32 is a cylindrical pin with a rounded tip. The tip of the pin 32 has a curved surface that is curved at least along the Y-axis direction. Here, the tip of the pin 32 is formed into a spherical shape. The detection tool 31 is formed into a rod shape extending in the Z-axis direction.

[0027] The detection tool 31 is configured to detect contact with the pin 32. Here, the detection tool 31 and the pin 32 are made of a conductor such as iron. A voltage is applied to at least one of the detection tool 31 and the pin 32. The detection tool 31 is configured to pass a current when it comes into contact with the pin 32. The correction device 60 detects the current to detect that the detection tool 31 has come into contact with the pin 32, and detects the positions of the detection tool 31 and the pin 32 at that time. Note that if the processing tool 6 is made of a conductor, the processing tool 6 may be used as the detection tool 31. The detection tool 31 may be a dedicated tool separate from the processing tool 6, or may be the processing tool 6.

[0028] Next, the process proceeds to step S2, where a first contact process is performed. In the first contact process, first, the detection tool 31 is moved in the X-axis direction to bring the detection tool 31 into contact with the pin 32 (see FIG. 11). Then, the position P11 (x11, y11) at this time is detected as the first contact position. Thereafter, the detection tool 31 is moved away from the pin 32.

[0029] Next, the process proceeds to step S3, where a rotation process is performed. In the rotation process, the clamp 50 is rotated 180 degrees around the A axis. Next, the process proceeds to step S4, where a movement process is performed. Here, the tip of the pin 32 is positioned at a distance L (see FIG. 11) from the A axis. Therefore, in the movement process, the clamp 50 is moved by 2L in the Y axis direction. As a result, the pin 32 is positioned to the side of the detection tool 31 (see the dashed line in FIG. 12).

[0030] Next, the process proceeds to step S5, where a second contact process is performed. As in the first contact process, in the second contact process, the detection tool 31 is moved in the X-axis direction to contact the pin 32 (see FIG. 12). Then, the position P12 (x12, y12) at this time is detected as the second contact position. Thereafter, the detection tool 31 is moved away from the pin 32.

[0031] Next, the process proceeds to step S6, where a correction process is executed. In the correction process, the coordinates are corrected based on the first contact position P11, the second contact position P12, and the movement distance 2L in the movement process so that the tilt of the Y axis with respect to the perpendicular to the A axis as viewed from the Z axis is eliminated. For example, as shown in FIG. 13, if the tilt angle of the Y axis with respect to the perpendicular to the A axis is θ, then sinθ=(x12-x11) / 2L. Since θ is a small angle, it can be considered that sinθ≒θ. Therefore, it can be calculated as θ=(x12-x11) / 2L. In this way, the tilt of the Y axis with respect to the perpendicular to the A axis can be detected, and the position coordinate can be corrected based on the tilt of the Y axis. For example, the corrected coordinate P'(x',y') for the coordinate P(x,y) can be calculated by subtracting x'=(x 2 +y 2 ) 0.5 ×sinθ, y´=(x 2 +y 2 ) 0.5 ×cosθ.

[0032] The above is the coordinate correction method for the cutting machine 10. When performing cutting, the workpiece 5 is attached to the clamp 50, and the processing tool 6 is attached to the spindle 30. The control device 90 controls the positions of the processing tool 6 and the clamp 50 based on the corrected coordinates. This allows cutting to be performed with high precision even if the Y-axis is tilted.

[0033] In the above method, the movement distance in the Y-axis direction during the movement process is calculated assuming it is equal to a predetermined distance 2L. However, the movement distance may also be detected based on contact between the detection tool 31 and the pin 32 in the Y-axis direction. For example, before or after the first contact process, the clamp 50 is moved in the Y-axis direction to bring the detection tool 31 and the pin 32 into contact, and the distance L1 between the center line of the pin 32 and the A-axis before the clamp 50 is rotated is detected. Also, before or after the second contact process, the clamp 50 is moved in the Y-axis direction to bring the detection tool 31 and the pin 32 into contact, and the distance L2 between the center line of the pin 32 and the A-axis after the clamp 50 is rotated is detected. As a result, the movement distance in the Y-axis direction is detected as L1 + L2. In this case, the tilt angle θ of the Y-axis can be calculated as θ = (x12 - x11) / (L1 + L2).

[0034] As described above, according to this embodiment, in the cutting machine 10 that controls cutting operations based on the X-, Y-, Z-, and A-axes, the tilt of the Y-axis with respect to the perpendicular line of the A-axis as viewed from the Z-axis is detected, and the coordinates are corrected to eliminate the tilt. Therefore, even if the Y-axis is tilted from the correct direction due to a component assembly error or aging, no coordinate error occurs when the clamp 50 is moved in a straight line along the Y-axis or rotated around the A-axis. This improves machining accuracy.

[0035] According to this embodiment, between the first contact process and the second contact process, a rotation process is performed to rotate the clamp 50 around the A axis, and a movement process is performed to move the clamp 50 in a straight line in the Y axis direction (see FIG. 10). Therefore, the first contact process and the second contact process can be performed using the same pin 32 as the pin with which the detection tool 31 comes into contact. If different pins are used in the first contact process and the second contact process, there is a risk that the accuracy of correction will decrease due to dimensional errors between the pins. However, by using the same pin 32 as in this embodiment, the tilt of the Y axis can be detected more accurately.

[0036] As shown in an exaggerated manner in FIGS. 14(a) and 14(b), if the tip of the pin 32 is flat, and the pin 32 is tilted, the position of the contact point between the detection tool 31 and the pin 32 in the X-axis direction may shift between the first contact process and the second contact process, even if the Y-axis is not tilted. However, according to this embodiment, the tip of the pin 32 has a curved surface that is curved at least along the Y-axis direction. Therefore, as shown in an exaggerated manner in FIGS. 14(c) and 14(d), even if the pin 32 is tilted, the position of the contact point between the detection tool 31 and the pin 32 in the X-axis direction is unlikely to shift between the first contact process and the second contact process. This reduces errors caused by the tilt of the pin 32, allowing for accurate detection of the Y-axis tilt.

[0037] (Second embodiment) The correction method according to the first embodiment is a method in which the detection tool is brought into contact with only one location on the correction jig when detecting the tilt of the Y-axis. The correction method according to the second embodiment is a method in which the detection tool is brought into contact with multiple locations on the correction jig when detecting the tilt of the Y-axis. Figure 15 is a flowchart of the coordinate correction method according to the second embodiment.

[0038] 16, in this embodiment, a first pin 32A and a second pin 32B are attached to a clamp 50 as a correction jig. The first pin 32A and the second pin 32B are attached at positions offset in the Y-axis direction from the A-axis. Like the pin 32 according to the first embodiment, the first pin 32A and the second pin 32B are cylindrical, conductive pins with rounded tips.

[0039] First, in step S11, the first pin 32A and the second pin 32B are attached to the clamp 50, and the detection tool 31 is attached to the spindle 30 (attachment process).

[0040] Next, the process proceeds to step S12, where the detection tool 31 is moved in the X-axis direction to bring the detection tool 31 into contact with the first pin 32A (first contact process; see arrow B1 in FIG. 16). Then, the position P11 (x11, y11) at this time is detected as the first contact position. The first pin 32A is an example of the first part of the correction jig. Thereafter, the detection tool 31 is moved away from the first pin 32A.

[0041] Next, the process proceeds to step S13, where the clamp 50 is moved by -2L in the Y-axis direction (first movement process). This positions the detection tool 31 to the side of the second pin 32B. Thereafter, the process proceeds to step S14, where the detection tool 31 is moved in the X-axis direction to contact the second pin 32B (third contact process; see arrow B3 in FIG. 16). The position P21 (x21, y21) at this time is detected as the third contact position. The second pin 32B is an example of the second part of the correction jig. Thereafter, the detection tool 31 is moved away from the second pin 32B.

[0042] Next, the process proceeds to step S15, where the clamp 50 is rotated 180 degrees around the A axis (rotation process). Subsequently, the process proceeds to step S16, where the detection tool 31 is moved in the X-axis direction to bring the detection tool 31 into contact with the first pin 32A (second contact process; see arrow B2 in FIG. 17). Then, the position P12 (x12, y12) at this time is detected as the second contact position. Thereafter, the detection tool 31 is moved away from the first pin 32A.

[0043] Next, the process proceeds to step S17, where the clamp 50 is moved by 2L in the Y-axis direction (second movement process). This positions the detection tool 31 to the side of the second pin 32B. Thereafter, the process proceeds to step S18, where the detection tool 31 is moved in the X-axis direction to contact the second pin 32B (fourth contact process; see arrow B4 in FIG. 17). The position P22 (x22, y22) at this time is detected as the fourth contact position.

[0044] Then, the process proceeds to step S19, where correction processing is performed. In this embodiment, similar to the first embodiment, the tilt angle θA of the Y-axis with respect to the perpendicular to the A-axis is calculated based on contact between the detection tool 31 and the first pin 32A. The tilt angle θA is calculated based on the first contact position P11, the second contact position P12, and the movement distance 2L in the first movement processing. Also, similar to the first embodiment, the tilt angle θB of the Y-axis with respect to the perpendicular to the A-axis is calculated based on contact between the detection tool 31 and the second pin 32B. The tilt angle θB is calculated based on the third contact position P21, the fourth contact position P22, and the movement distance 2L in the second movement processing. Then, the tilt angle θ is calculated by averaging the tilt angle θA calculated based on contact with the first pin 32A and the tilt angle θB calculated based on contact with the second pin 32B. That is, θ = (θA + θB) / 2. In this embodiment, the position coordinates are corrected based on the tilt of the Y axis calculated in this manner.

[0045] In the above method, the movement distances in the first movement process (step S13) and the second movement process (step S17) are set to predetermined distances -2L and 2L, respectively. However, the movement distances may be detected based on contact between the detection tool 31 and the first pin 32A and the second pin 32B in the Y-axis direction. Note that the method for detecting the movement distance based on contact with the pins in the Y-axis direction is the same as the method described above, and therefore, a description thereof will be omitted here.

[0046] 18, the correction device 60 according to this embodiment has processing units that perform the above-described processes. That is, the correction device 60 has a first contact processing unit 61 that performs the first contact processing, a second contact processing unit 62 that performs the second contact processing, a third contact processing unit 61A that performs the third contact processing, a fourth contact processing unit 62A that performs the fourth contact processing, a first movement processing unit 64A that performs the first movement processing, a second movement processing unit 64B that performs the second movement processing, a rotation processing unit 63 that performs the rotation processing, and a correction processing unit 65 that performs the correction processing.

[0047] In this embodiment as well, when performing cutting, the workpiece 5 is attached to the clamp 50, and the processing tool 6 is attached to the spindle 30. The control device 90 controls the positions of the processing tool 6 and the clamp 50 based on the corrected coordinates. This allows for accurate cutting even when the Y-axis is tilted.

[0048] As described above, according to this embodiment, when detecting the tilt of the Y-axis, the detection tool is brought into contact with multiple locations on the correction jig. The tilt of the Y-axis is calculated for each contact with each location, and the average value of these tilts is set as the tilt of the Y-axis. Therefore, according to this embodiment, the position coordinates can be corrected with higher precision. Therefore, cutting can be performed with higher precision.

[0049] In this embodiment, a first pin 32A and a second pin 32B are used as the correction jig. Similar to the pin 32 according to the first embodiment, the tips of the first pin 32A and the second pin 32B have curved surfaces that curve along the Y-axis direction. This reduces errors caused by the tilt of the first pin 32A and the second pin 32B, enabling the tilt of the Y-axis to be detected with high accuracy.

[0050] While the first and second embodiments of the cutting machine and coordinate correction method have been described above, the above-described embodiments are merely examples, and various other embodiments are possible. Next, examples of other embodiments will be briefly described.

[0051] In the first embodiment, in order to bring the detection tool 31 into contact with the same pin 32 in the first contact process and the second contact process, a rotation process is performed in which the clamp 50 is rotated 180 degrees around the A axis, and a movement process is performed in which the clamp 50 is moved in the Y axis direction. That is, in order to bring the detection tool into contact with the same portion (first portion) of the correction jig, both the rotation process and the movement process are performed. However, the detection tool may be brought into contact with different portions of the correction jig in the first contact process and the second contact process. In this case, it is possible to omit either the rotation process or the movement process.

[0052] In the second embodiment, the first pin 32A and the second pin 32B are separate from each other, but they may be integrated. That is, the correction jig may be composed of multiple items, or may be composed of a single item. The shape of the correction jig does not have to be pin-shaped. For example, as shown in FIG. 19, a rectangular parallelepiped correction jig 32C may be used. Furthermore, as shown in FIG. 20, a rectangular parallelepiped correction jig 32D having a curved surface curved at least along the Y-axis direction may be used.

[0053] In each of the above embodiments, the spindle 30 moves straight in the X-axis and Z-axis directions, and the clamp 50 moves straight in the Y-axis direction and rotates around the A-axis. However, the cutting machine 10 only needs to be able to move the spindle 30 straight in the X-axis, Y-axis, and Z-axis directions relative to the clamp 50 and rotate around the A-axis. For example, the cutting machine 10 may be configured so that the spindle 30 moves straight in the X-axis, Y-axis, and Z-axis directions, and the clamp 50 rotates around the A-axis.

[0054] Although the cutting machine 10 according to the embodiment is a dental cutting machine, the use of the cutting machine is not limited to dental use. [Explanation of symbols]

[0055] 5 Workpiece 6 Processing Tools 10 Cutting machine 25 Drive unit 30 Spindle (second holding member) 31 Discovery Tools 32 pins (correction jig) 32A 1st pin (correction jig) 32B 2nd pin (correction jig) 50 clamp (first holding member) 60 Correction Device 90 Control device

Claims

1. a first holding member that holds the workpiece; a second holding member for holding a processing tool for cutting the workpiece; a drive device that drives at least one of the first holding member and the second holding member to move the machining tool linearly relative to the workpiece in directions of an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other, and rotates the workpiece relative to the machining tool around an A-axis that is parallel to the X-axis; A method for correcting position coordinates of a cutting machine comprising: a mounting process of mounting a correction jig on the first holding member and mounting a detection tool that detects contact with the correction jig on the second holding member; a first contact process of bringing the detection tool held by the second holding member into contact with the correction jig held by the first holding member by moving the second holding member relatively to the first holding member in an X-axis direction, and acquiring a first contact position; a first movement process of moving the second holding member by a first distance relative to the first holding member in a Y-axis direction; a second contact process in which, after the first movement process, the second holding member is moved relatively to the first holding member in an X-axis direction to bring the detection tool held by the second holding member into contact with the correction jig held by the first holding member, thereby acquiring a second contact position; a correction process for correcting position coordinates based on at least the first contact position, the second contact position, and the first distance so that the Y axis is perpendicular to the A axis when viewed from the Z axis; A coordinate correction method for a cutting machine, comprising:

2. the first contact process includes a process of acquiring the first contact position by bringing the detection tool into contact with a first portion of the correction jig; performing a rotation process after the first contact process and before the second contact process, in which the first holding member to which the correction jig is attached is rotated 180 degrees around the A axis relative to the second holding member; The coordinate correction method for a cutting machine according to claim 1 , wherein the second contact process includes a process of acquiring the second contact position by bringing the detection tool into contact with the first portion of the correction jig.

3. 3. The coordinate correction method for a cutting machine according to claim 2, wherein the first portion of the correction jig has a curved surface that is curved at least along the Y-axis direction.

4. a third contact process of acquiring a third contact position by bringing the detection tool held by the second holding member into contact with a second portion of the correction jig held by the first holding member; a second movement process of relatively moving the second holding member a second distance in a Y-axis direction with respect to the first holding member; a fourth contact process of acquiring a fourth contact position by bringing the detection tool into contact with the second portion of the correction jig after the second movement process, The correction process includes: calculating a first tilt angle of the Y-axis with respect to a perpendicular line of the A-axis as viewed from the Z-axis based on the first contact position, the second contact position, and the first distance; calculating a second tilt angle of the Y-axis with respect to a perpendicular line of the A-axis as viewed from the Z-axis based on the third contact position, the fourth contact position, and the second distance; 3. The coordinate correction method for a cutting machine according to claim 2, further comprising: a process of correcting position coordinates based on the first tilt angle and the second tilt angle so that the Y axis is perpendicular to the A axis when viewed from the Z axis.

5. 5. The coordinate correction method for a cutting machine according to claim 4, wherein the first portion and the second portion of the correction jig have curved surfaces that are curved at least along the Y-axis direction.

6. a first holding member that holds the workpiece; a second holding member for holding a processing tool for cutting the workpiece; a drive device that drives at least one of the first holding member and the second holding member to move the machining tool linearly relative to the workpiece in directions of an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other, and rotates the workpiece relative to the machining tool around an A-axis that is parallel to the X-axis; a correction jig held by the first holding member; a detection tool held by the second holding member; a correction device for correcting position coordinates, The correction device a first contact processing unit that performs first contact processing to acquire a first contact position by moving the second holding member relatively to the first holding member in an X-axis direction to bring the detection tool held by the second holding member into contact with the correction jig held by the first holding member; a movement processing unit that performs movement processing to move the second holding member by a first distance relative to the first holding member in a Y-axis direction; a second contact processing unit that performs a second contact processing, in which, after the movement processing, the second holding member is moved relatively to the first holding member in an X-axis direction to bring the detection tool held by the second holding member into contact with the correction jig held by the first holding member, thereby acquiring a second contact position; a correction processing unit that corrects position coordinates based on at least the first contact position, the second contact position, and the first distance so that the Y axis is perpendicular to the A axis when viewed from the Z axis.

7. the first contact processing unit is configured to acquire the first contact position by bringing the detection tool into contact with a first portion of the correction jig; the correction device has a rotation processing unit that executes a rotation process to rotate the first holding member, to which the correction jig is attached, by 180 degrees around an A-axis relative to the second holding member after the first contact process and before the second contact process, The cutting machine according to claim 6 , wherein the second contact processing unit is configured to acquire the second contact position by bringing the detection tool into contact with the first portion of the correction jig.

8. The cutting machine according to claim 6 , wherein the first portion of the correction jig has a curved surface that is curved at least along the Y-axis direction.

9. The correction device a third contact processing unit that performs third contact processing to acquire a third contact position by bringing the detection tool held by the second holding member into contact with a second portion of the correction jig held by the first holding member; a second movement processing unit that performs a second movement process to move the second holding member a second distance relative to the first holding member in a Y-axis direction; a fourth contact processing unit that performs a fourth contact processing to acquire a fourth contact position by bringing the detection tool into contact with the second portion of the correction jig after the second movement processing, The correction processing unit calculating a first tilt angle of the Y-axis with respect to a perpendicular line of the A-axis as viewed from the Z-axis based on the first contact position, the second contact position, and the first distance; calculating a second tilt angle of the Y-axis with respect to a perpendicular line of the A-axis as viewed from the Z-axis based on the third contact position, the fourth contact position, and the second distance; and correcting position coordinates based on the first tilt angle and the second tilt angle so that the Y-axis is perpendicular to the A-axis when viewed from the Z-axis.

10. The cutting machine according to claim 9 , wherein the first portion and the second portion of the correction jig have curved surfaces that are curved at least along the Y-axis direction.

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