Workpiece gripping member

Abstract

To provide a machine tool that allows for the replacement of sub-collets without moving the spindle. [Solution] The machine tool 100 is equipped with a detachable mechanism AD that allows a workpiece to be attached to and detached from the main collet MC mounted on the spindle, and a sub-collet SC to be attached to and detached from the main collet MC. The detachable mechanism AD has a base BP that is movable along the first moving axis DX1, and an arm AP that extends radially outward from the base BP in a circle centered on the first moving axis DX1. The arm AP is configured to be rotatable around the first moving axis DX1. A first gripping mechanism GM1 capable of individually gripping the workpiece and the sub-collet SC is attached to the tip of the arm AP.

Description

Technical Field

[0001] The present disclosure relates to a machine tool, a control method for a machine tool, and a program.

Background Art

[0002] Conventionally, an inverted lathe (a machine tool) provided with an automatic exchange mechanism for a collet gripped by a spindle chuck is known (see Patent Document 1). This automatic exchange mechanism is configured such that the chuck can be exchanged by moving the spindle in a direction perpendicular to the axial direction of the spindle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] However, in the above-mentioned automatic exchange mechanism, since it is necessary to move the spindle when exchanging the collet, the structure becomes complicated.

[0005] Accordingly, it is desirable to provide a machine tool that allows the collet to be exchanged without moving the spindle.

Means for Solving the Problem

[0006] A machine tool according to one embodiment of the present disclosure includes a spindle and a detachable mechanism that allows a workpiece to be attached to and detached from an outer collet attached to the spindle, and an inner collet to be attached to and detached from the outer collet attached to the spindle, wherein the detachable mechanism has a base that is movable along a first moving axis that extends parallel to the axial direction of the spindle, and an arm that extends radially outward from the base in a circle centered on the first moving axis, the arm is configured to be rotatable around the first moving axis, and a first gripping mechanism capable of individually gripping the workpiece and the inner collet is attached to the tip of the arm. [Effects of the Invention]

[0007] The aforementioned machine tool allows for collet replacement without moving the spindle. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of a machine tool according to an embodiment of the present disclosure. [Figure 2] This is an exploded perspective view of the main collet, sub-collet, anti-loosening mechanism, collet receiving member, and extrusion mechanism. [Figure 3] This is a cross-sectional view of the main collet, sub-collet, anti-loosening mechanism, and collet receiving member. [Figure 4] This is a cross-sectional view of the main collet, sub-collet, anti-loosening mechanism, collet receiving member, and extrusion mechanism. [Figure 5] This is a perspective view (part 1) of the spindle unit. [Figure 6] This is a perspective view (part 2) of the spindle unit. [Figure 7] This is a perspective view (part 3) of the spindle unit. [Figure 8] This is a perspective view (part 4) of the spindle unit. [Figure 9] This is a perspective view (part 5) of the spindle unit. [Figure 10] This is a perspective view (part 6) of the spindle unit. [Figure 11]It is a perspective view (part 7) of the spindle unit. [Figure 12] It is a perspective view (part 8) of the spindle unit. [Figure 13] It is a perspective view (part 9) of the spindle unit. [Figure 14] It is a perspective view (part 10) of the spindle unit. [Figure 15] It is a perspective view (part 1) of the second movable assembly and the thickness measurement mechanism. [Figure 16] It is a right side view and a front view of the fixed wall portion and the washer. [Figure 17] It is a perspective view (part 2) of the second movable assembly and the thickness measurement mechanism. [Figure 18] It is a perspective view (part 3) of the second movable assembly and the thickness measurement mechanism. [Figure 19] It is a perspective view (part 4) of the second movable assembly and the thickness measurement mechanism. [Figure 20] It is a perspective view (part 5) of the second movable assembly and the thickness measurement mechanism. [Figure 21] It is a flowchart showing an example of the flow of sub-collet replacement processing. [Figure 22] It is a flowchart showing an example of the flow of thickness measurement processing. [Mode for Carrying Out the Invention]

[0009] Hereinafter, a machine tool 100 according to an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a perspective view of the machine tool 100. Specifically, the upper view of FIG. 1 is a perspective view of the machine tool 100 to which a cover CV is attached, and the lower view of FIG. 1 is a perspective view of a spindle unit MU disposed inside the cover CV.

[0010] In Figure 1, X1 represents one direction of the X axis constituting a three-dimensional orthogonal coordinate system, and X2 represents the other direction of the X axis. Y1 represents one direction of the Y axis constituting the three-dimensional orthogonal coordinate system, and Y2 represents the other direction of the Y axis. Similarly, Z1 represents one direction of the Z axis constituting the three-dimensional orthogonal coordinate system, and Z2 represents the other direction of the Z axis. In Figure 1, the X1 side of the machine tool 100 corresponds to the front side (front face side) of the machine tool 100, and the X2 side of the machine tool 100 corresponds to the rear side (rear face side) of the machine tool 100. The Y1 side of the machine tool 100 corresponds to the left side of the machine tool 100, and the Y2 side of the machine tool 100 corresponds to the right side of the machine tool 100. The Z1 side of the machine tool 100 corresponds to the upper side of the machine tool 100, and the Z2 side of the machine tool 100 corresponds to the lower side of the machine tool 100. The same applies to other figures.

[0011] The machine tool 100 is an apparatus that processes a workpiece such as a bar material BR gripped by a main collet MC which is a collet mounted on a rotating main spindle MS, or a sub-collet SC which is a collet mounted on the main collet MC, using a cutting tool. As shown in the upper diagram of Figure 1, the machine tool 100 further includes a controller CTR that controls the movement of the machine tool 100. In the illustrated example, the controller CTR is configured to include a computer (microcomputer) provided with a CPU, a volatile storage device, a non-volatile storage device, an input / output interface, and the like. Specifically, the controller CTR can output control commands to various mechanisms constituting the spindle unit MU to operate the various mechanisms, as the CPU executes a program stored in a storage medium such as the non-volatile storage device. In the example shown in the lower diagram of Figure 1, a collet receiving member CR is attached to the tip of the main spindle MS, the main collet MC is mounted on the collet receiving member CR, the sub-collet SC is mounted on the main collet MC, and the bar material BR is gripped by the sub-collet SC.

[0012] The spindle unit MU is configured to include the main spindle MS, an attachment / detachment mechanism AD, a conveyance mechanism CD, a collet holder moving mechanism CM, and a thickness measurement mechanism TM.

[0013] The attachment / detachment mechanism AD is a mechanism for attaching and detaching the attachment / detachment member to the spindle MS. The attachment / detachment member includes the sub-collet SC and the rod BR.

[0014] The transport mechanism CD is a mechanism for transferring the member to be attached or detached between it and the attachment / detachment mechanism AD.

[0015] The collet holder movement mechanism CM is a mechanism for moving a collet holder CH on which one or more sub-collets SC are mounted in parallel. In the illustrated example, the collet holder CH is configured to accommodate 15 sub-collets SC arranged in three rows of five along the axial direction (Y-axis direction) of the main spindle MS.

[0016] The thickness measuring mechanism TM is a mechanism for measuring the thickness of a finished workpiece, such as a washer, that has been cut by the machine tool 100.

[0017] Next, with reference to Figures 2 to 4, the components arranged at the tip of the spindle MS will be described. Figure 2 is an exploded perspective view of the components arranged at the tip of the spindle MS. In the illustrated example, the components arranged at the tip of the spindle MS include a pull-out prevention mechanism CP, a sub-collet SC, a main collet MC, a collet receiving member CR, and an extrusion mechanism PS.

[0018] The sub-collet SC comprises a pin 10, a main body member 11, and a movable member 12. The main body member 11 is a member that forms the outer circumferential surface of the sub-collet SC and has a through hole 11H through which the pin 10 is inserted. The main body member 11 also has a flange portion 11F to prevent it from being completely inserted into the main collet MC, and a groove portion 11G used for engagement with the collet receiving member CR. The movable member 12 is a member that is housed inside the main body member 11 so as to be slidable along the axial direction of the spindle MS, and has a groove portion 12G for slidably receiving the pin 10. The movable member 12 also has a flange portion 12F at its rear end and is configured so that when it moves (slides) forward inside the main body member 11, its tip portion 12E protrudes from the tip portion of the main body member 11.

[0019] The main collet MC is configured to either directly grip the bar stock BR ​​or indirectly grip the bar stock BR ​​via the sub-collet SC. In the illustrated example, the main collet MC is a collet used in a quick-change collet chuck system and has a pin hole PH and a groove CG used for engagement with the collet receiving member CR.

[0020] The collet receiving member CR is a member for receiving the main collet MC and is attached to the tip of the spindle MS. In the illustrated example, the collet receiving member CR consists of a cylindrical member 30, a bolt 31, and a flange member 32. The cylindrical member 30 is the member on which the main collet MC is mounted. The bolt 31 is an example of a fastening member for connecting the cylindrical member 30 and the flange member 32. The flange member 32 is a member fixed to the tip of the spindle MS.

[0021] The anti-dislodgement mechanism CP is a mechanism for preventing the sub-collet SC, which is mounted on the main collet MC, from coming off the main collet MC. In the illustrated example, the anti-dislodgement mechanism CP is composed of a metal ball 20, an O-ring 21, and a collet connecting member 22. The collet connecting member 22 is configured such that its outer circumferential surface contacts the inner circumferential surface of the cylindrical member 30 of the collet receiving member CR, and its inner circumferential surface contacts the outer circumferential surface of the member to be attached and detached.

[0022] The extrusion mechanism PS is a mechanism for pushing the rod BR, which is held by the sub-collet SC, out of the sub-collet SC. In the illustrated example, the extrusion mechanism PS includes a pneumatic cylinder positioned along the rotation axis MX of the spindle MS. The extrusion mechanism PS may also include other optional actuators.

[0023] Next, with reference to Figure 3, the positional relationship of the components positioned at the tip of the spindle MS will be explained. Figure 3 is a cross-sectional view of the components positioned at the tip of the spindle MS. Note that, for clarity, the cross-section of the anti-detachment mechanism CP is omitted in Figure 3. Specifically, the left side of Figure 3 shows the state when the sub-collet SC is installed, and the right side of Figure 3 shows the state when the sub-collet SC is not installed.

[0024] Specifically, the sub-collet SC is attached to the cylindrical member 30 of the collet receiving member CR via an anti-loosening mechanism CP, as shown in Figure 3. Specifically, the collet connecting member 22 of the anti-loosening mechanism CP has a first groove 22G1 into which 12 metal balls 20 and an O-ring 21 are fitted. The 12 metal balls 20 are fitted into 12 through holes 22H formed at the bottom of the first groove 22G1, and the O-ring 21 is positioned outside the 12 metal balls 20 so as to push each of the 12 metal balls 20 inward (towards the rotation axis MX). The diameter of the through holes 22H is smaller than the diameter of the metal balls 20. Therefore, the metal balls 20 will not fall out through the through holes 22H.

[0025] Furthermore, the collet connecting member 22 has a second groove 22G2 for receiving three conical protrusions 30T formed on the inner circumferential surface of the cylindrical member 30 of the collet receiving member CR. This configuration prevents the collet connecting member 22 from falling out of the cylindrical member 30.

[0026] A portion of the metal ball 20, which partially protrudes inward from the through hole 22H of the collet connecting member 22, enters into and engages with the groove 11G formed in the main body member 11 of the sub-collet SC. This engagement between the metal ball 20 and the groove 11G holds the sub-collet SC in place, preventing it from falling out of the main collet MC.

[0027] The main collet MC is configured to expand and contract radially. Three pin holes PH are formed on the outer circumferential surface of the main collet MC to receive three pins 30P provided on the inner circumferential surface of the cylindrical member 30 of the collet receiving member CR. A groove CG is also formed on the outer circumferential surface of the main collet MC to engage with the inner annular portion 30N provided on the inner circumferential surface of the cylindrical member 30. This engagement between the pins 30P and the pin holes PH enables the main collet MC to be positioned circumferentially around the rotation axis MX. Furthermore, this engagement between the inner annular portion 30N and the groove CG prevents the main collet MC from falling out of the collet receiving member CR.

[0028] Next, referring to Figure 4, the movement of the sub-collet SC when the rod BR, which is gripped by the sub-collet SC, is pushed out of the sub-collet SC by the extrusion mechanism PS will be explained. Figure 4 is a cross-sectional view of the member located at the tip of the main spindle MS. Specifically, Figure 4 shows the four states (first state STa to fourth state STd) of the member located at the tip of the main spindle MS. In the illustrated example, when the rod BR gripped by the sub-collet SC is pushed out, the state of the member located at the tip of the main spindle MS transitions in the order of first state STa, second state STb, third state STc, and fourth state STd.

[0029] In the first state STa, the tip of the extrusion mechanism PS (the end on the Y1 side, the left end) is located away from the sub-collet SC.

[0030] Subsequently, when the extrusion mechanism PS is moved to the Y1 side (left), the tip of the extrusion mechanism PS comes into contact with the flange portion 12F of the movable member 12 of the sub-collet SC, as shown in the second state STb.

[0031] Subsequently, when the extrusion mechanism PS is moved further towards Y1 (to the left), the tip of the extrusion mechanism PS moves further towards Y1 (to the left), pushing the movable member 12 (flange portion 12F) towards Y1 (to the left). At this time, the pin 10 of the sub-collet SC slides within the groove 12G of the movable member 12 until the tip 12E of the movable member 12 comes into contact with the rear end (the end on the Y2 side, the right end) of the rod BR.

[0032] Subsequently, when the extrusion mechanism PS is moved further to the Y1 side (left), the flange portion 12F of the movable member 12 comes into contact with the stepped portion 11S of the main body member 11 of the sub-collet SC. This contact stops the movement of the extrusion mechanism PS to the Y1 side (left). At this time, the tip portion 12E of the movable member 12 protrudes further to the Y1 side (left) than the flange portion 11F of the main body member 11, and the rod BR, which is pushed to the Y1 side (left) by the tip portion 12E of the movable member 12, also moves further to the Y1 side (left) than the flange portion 11F of the main body member 11.

[0033] In this way, the rod BR, which is pushed out from the tip of the sub-collet SC, is gripped by the first gripping mechanism GM1 (see Figure 5), which is not shown in Figure 4, and is separated from the sub-collet SC and moved to another position.

[0034] Next, the spindle unit MU will be described with reference to Figure 5. Figure 5 is a perspective view of the spindle unit MU. In the illustrated example, the spindle unit MU is composed of the first actuator AC1 to the seventh actuator AC7, the attachment / detachment mechanism AD, the transport mechanism CD, the collet holder moving mechanism CM, the first gripping mechanism GM1, the second gripping mechanism GM2, the spindle MS, and the thickness measuring mechanism TM.

[0035] The first actuator AC1 is an actuator that moves the first movable assembly MA1 along a first moving axis DX1 parallel to the axial direction (Y-axis direction) of the spindle MS relative to the frame of the machine tool 100. The first movable assembly MA1 includes an arm AP, a base BP, and a cover LD. In the illustrated example, the first actuator AC1 is a ball screw driven electric actuator. However, the first actuator AC1 may be any other actuator.

[0036] The arm AP is a member that is pivotably connected to the base BP, and the third actuator AC3 and the first gripping mechanism GM1 are fixed to its tip.

[0037] The base BP is a component configured to be movable along the axial direction of the spindle MS relative to the frame of the machine tool 100. In the illustrated example, the second actuator AC2 is fixed to the base BP.

[0038] The cover portion LD is a component attached to the tip of the base portion BP (the end on the Y1 side, the left end), and is a component for protecting the attachment / detachment mechanism AD and the transport mechanism CD from chips generated when the machine tool 100 cuts a workpiece, or from cleaning fluids used to clean the workpiece or cutting tools. In the illustrated example, the cover portion LD is configured as a component that closes a through hole HL provided in the partition wall PW that separates the inside and outside of the machining space SP of the machine tool 100. The first actuator AC1 can cover the through hole HL with the cover portion LD by moving the base portion BP, to which the cover portion LD is fixed at the tip (protruding into the machining space SP), toward the Y2 side (to the right).

[0039] The second actuator AC2 is an actuator that swings the arm AP around the first moving axis DX1 relative to the base BP. In the illustrated example, the second actuator AC2 is an electric servo motor. However, the second actuator AC2 may be any other actuator.

[0040] The third actuator AC3 is an actuator for operating the first gripping mechanism GM1. In the illustrated example, the third actuator AC3 is an electric actuator attached to the tip of the arm AP. However, the third actuator AC3 may be any other actuator.

[0041] The first gripping mechanism GM1 is a mechanism for gripping the member to be attached or detached. In the illustrated example, the first gripping mechanism GM1 is attached to the tip of the arm AP together with the third actuator AC3, and is configured so that a pair of claws can be opened and closed by the third actuator AC3.

[0042] The fourth actuator AC4 is an actuator for operating the second gripping mechanism GM2. In the illustrated example, the fourth actuator AC4 is a pneumatic actuator attached to the second movable assembly MA2. However, the fourth actuator AC4 may be any other actuator.

[0043] The second gripping mechanism GM2 is a mechanism for gripping the member to be attached or detached. In the illustrated example, the second gripping mechanism GM2 is attached to the second movable assembly MA2 together with the fourth actuator AC4, and is configured so that a pair of claws can be opened and closed by the fourth actuator AC4.

[0044] The fifth actuator AC5 is an actuator that moves the collet holder CH along the second movement axis DX2, which is perpendicular to the axial direction (Y-axis direction) of the spindle MS, relative to the frame of the machine tool 100. In the illustrated example, the fifth actuator AC5 is a ball screw-driven electric actuator. However, the fifth actuator AC5 may be any other actuator.

[0045] The sixth actuator AC6 is an actuator that moves the second movable assembly MA2 along the third moving axis DX3, which is parallel to the axial direction (Y-axis direction) of the spindle MS, relative to the frame of the machine tool 100. In the illustrated example, the sixth actuator AC6 is a ball screw driven electric actuator. However, the sixth actuator AC6 may be any other actuator.

[0046] The seventh actuator AC7 is an actuator that moves the second gripping mechanism GM2 relative to the second movable assembly MA2 along the fourth moving axis DX4, which is perpendicular to the axial direction (Y-axis direction) of the main spindle MS. In the illustrated example, the seventh actuator AC7 is a ball screw driven electric actuator. However, the seventh actuator AC7 may be any other actuator.

[0047] In the illustrated example, the attachment / detachment mechanism AD comprises a first actuator AC1 and a first movable assembly MA1. The first movable assembly MA1 comprises a second actuator AC2, a third actuator AC3, an arm AP, a base BP, a first gripping mechanism GM1, and a lid LD. The transport mechanism CD comprises a sixth actuator AC6 and a second movable assembly MA2. The second movable assembly MA2 comprises a fourth actuator AC4, a seventh actuator AC7, and a second gripping mechanism GM2. The collet holder moving mechanism CM comprises a fifth actuator AC5 and a collet holder CH.

[0048] Next, the movement of the spindle unit MU will be explained with reference to Figures 6 to 11. Figures 6 to 11 are perspective views of the spindle unit MU. Specifically, Figures 6, 7, 10, and 11 are overall perspective views of the spindle unit MU, while Figures 8 and 9 are enlarged perspective views of a part of the spindle unit MU (the area R1 enclosed by the dashed line in Figure 7). Furthermore, Figure 6 shows the four states of the spindle unit MU (first state ST1 to fourth state ST4), Figure 7 shows the four states of the spindle unit MU (fifth state ST5 to eighth state ST8), and Figure 8 shows the three states of the spindle unit MU (ninth state ST9 to eleventh state ST11). Furthermore, Figure 9 shows the three states of the spindle unit MU (states 12 to 14, ST12 and ST14), Figure 10 shows the four states of the spindle unit MU (states 15 to 18, ST18), and Figure 11 shows the three states of the spindle unit MU (states 19 to 21, ST21).

[0049] In the illustrated example, when replacing the first sub-collet SC1 mounted on the spindle MS with the second sub-collet SC2 held in the collet holder CH, the state of the spindle unit MU transitions in the following order: first state ST1, second state ST2, ..., 20th state ST20, and 21st state ST21.

[0050] In the initial state, the first state ST1, the spindle unit MU (detachable mechanism AD) has its base BP retracted to the Y2 side (right side) of the partition wall PW so that the through hole HL formed in the partition wall PW can be closed by the cover LD. Also, a sub-collet SC (first sub-collet SC1) is attached to the spindle MS, and another sub-collet SC (second sub-collet SC2) is held (stored) in the collet holder CH.

[0051] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y1 side (left), as indicated by arrow AR1 in the second state ST2.

[0052] Subsequently, the spindle unit MU (detachable mechanism AD) drives the second actuator AC2 to swing the arm AP downward around the first movement axis DX1, as indicated by arrow AR2 in the third state ST3. Specifically, the spindle unit MU (detachable mechanism AD) swings the arm AP downward around the first movement axis DX1 until the central axis GX1 of the first gripping mechanism GM1, which is fixed to the tip of the arm AP, and the rotation axis MX of the spindle MS (central axis SX1 of the first sub-collet SC1) coincide (become aligned in the same line).

[0053] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y2 side (right), as indicated by arrow AR3 in the fourth state ST4. As a result, the first gripping mechanism GM1 can position a pair of claws around the flange portion 11F of the first sub-collet SC1 mounted on the main collet MC. The first gripping mechanism GM1 then uses the force generated by the third actuator AC3 to grip the flange portion 11F of the main body member 11 of the first sub-collet SC1.

[0054] Subsequently, the spindle unit MU (detachment mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y1 side (left), as shown by arrow AR4 in the fifth state ST5 in Figure 7. As a result, the first gripping mechanism GM1 is able to pull the first sub-collet SC1, which is attached to the main collet MC, away from the main collet MC.

[0055] Subsequently, the spindle unit MU (detachable mechanism AD) drives the second actuator AC2 to swing the arm AP upward around the first movement axis DX1, as indicated by arrow AR5 in the sixth state ST6. Specifically, the spindle unit MU (detachable mechanism AD) swings the arm AP upward around the first movement axis DX1 until it reaches the position in the second state ST2 in Figure 6.

[0056] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y2 side (right), as indicated by the arrow AR6 in the seventh state ST7. Specifically, the spindle unit MU (detachable mechanism AD) moves the first movable assembly MA1 to the Y2 side (right) until it reaches the position in the first state ST1 in Figure 6. As a result, the spindle unit MU (detachable mechanism AD) can position the first gripping mechanism GM1, which has a pair of claws that open and close in the vertical direction, against the second gripping mechanism GM2, which has a pair of claws that open and close in the front-rear direction. In other words, the spindle unit MU (detachable mechanism AD) can align the central axis GX1 of the first gripping mechanism GM1 with the central axis GX2 of the second gripping mechanism GM2. Therefore, the second gripping mechanism GM2 can position its pair of claws around the first sub-collet SC1, which is gripped by the first gripping mechanism GM1. The second gripping mechanism GM2 then grips the first sub-collet SC1 using the force generated by the fourth actuator AC4. After the first sub-collet SC1 is gripped by the second gripping mechanism GM2, the first gripping mechanism GM1 releases the first sub-collet SC1 by opening a pair of claws vertically using the third actuator AC3. In this way, the spindle unit MU achieves the transfer of the first sub-collet SC1 from the first gripping mechanism GM1 to the second gripping mechanism GM2.

[0057] Subsequently, the spindle unit MU (collet holder moving mechanism CM) drives the fifth actuator AC5 to move the collet holder CH towards X1 (forward) along the second movement axis DX2, as indicated by the arrow AR7 in the eighth state ST8. Specifically, the spindle unit MU (collet holder moving mechanism CM) moves the collet holder CH towards X1 (forward) until the X coordinate (position in the X-axis direction) of the second gripping mechanism GM2 (first sub-collet SC1) matches the X coordinate of the storage space SG1 in the collet holder CH (the location where the first sub-collet SC1 is stored).

[0058] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 along the third moving axis DX3 to the Y2 side (right), as shown by arrow AR8 in the ninth state ST9 in Figure 8. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y2 side (right) until the Y coordinate (position in the Y-axis direction) of the second gripping mechanism GM2 (first sub-collet SC1) coincides with the Y coordinate of the storage space SG1 in the collet holder CH.

[0059] Subsequently, the spindle unit MU (transport mechanism CD) drives the seventh actuator AC7 to move the second movable assembly MA2 along the fourth moving axis DX4 towards the Z2 side (downward), as indicated by the arrow AR9 in the tenth state ST10. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 towards the Z2 side (downward) until the Z coordinate (position in the Z-axis direction) of the second gripping mechanism GM2 (first sub-collet SC1) coincides with the Z coordinate of the storage space SG1 in the collet holder CH. Then, the second gripping mechanism GM2 releases the first sub-collet SC1 by opening a pair of claws in the front-rear direction with the fourth actuator AC4. In this way, the spindle unit MU can place (store) the first sub-collet SC1 in the storage space of the collet holder CH.

[0060] Subsequently, the spindle unit MU (transport mechanism CD) drives the seventh actuator AC7 to move the second movable assembly MA2 toward the Z1 side (upwards) along the fourth moving axis DX4, as indicated by the arrow AR10 in the eleventh state ST11. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 toward the Z1 side (upwards) until it reaches the position in the ninth state ST9.

[0061] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 along the third moving axis DX3 to the Y2 side (right), as shown by arrow AR11 in the 12th state ST12 in Figure 9. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y2 side (right) until the Y coordinate (position in the Y-axis direction) of the second gripping mechanism GM2 coincides with the Y coordinate of the storage space SG2 in the collet holder CH (the location where the second sub-collet SC2 is stored; see the 14th state ST14).

[0062] Furthermore, the spindle unit MU (collet holder moving mechanism CM) drives the fifth actuator AC5 to move the collet holder CH toward the X1 side (forward) along the second moving axis DX2, as indicated by the arrow AR12. Specifically, the spindle unit MU (collet holder moving mechanism CM) moves the collet holder CH toward the X1 side (forward) until the X coordinate (position in the X-axis direction) of the second gripping mechanism GM2 coincides with the X coordinate of the storage space SG2 in the collet holder CH.

[0063] Subsequently, the spindle unit MU (transport mechanism CD) drives the seventh actuator AC7 to move the second movable assembly MA2 toward the Z2 side (downward) along the fourth moving axis DX4, as indicated by the arrow AR13 in the 13th state ST13. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 toward the Z2 side (downward) until the Z coordinate (position in the Z-axis direction) of the second gripping mechanism GM2 coincides with the Z coordinate of the storage space SG2 in the collet holder CH. Then, the second gripping mechanism GM2 grips the second sub-collet SC2 by closing a pair of claws in the front-rear direction with the fourth actuator AC4.

[0064] Subsequently, the spindle unit MU (transport mechanism CD) drives the seventh actuator AC7 to move the second movable assembly MA2 toward Z1 (upward) along the fourth moving axis DX4, as indicated by the arrow AR14 in the 14th state ST14. In this way, the spindle unit MU can lift the second sub-collet SC2 which is placed (stored) in the storage space of the collet holder CH.

[0065] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 along the third moving axis DX3 to the Y1 side (left), as shown by arrow AR15 in state ST15 of Figure 10. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y1 side (left) to a position where the second sub-collet SC2 can be transferred from the second gripping mechanism GM2 to the first gripping mechanism GM1. After that, the first gripping mechanism GM1 grips the second sub-collet SC2 using the force generated by the third actuator AC3. After the second sub-collet SC2 is gripped by the first gripping mechanism GM1, the second gripping mechanism GM2 releases the second sub-collet SC2 by opening a pair of claws in the front-rear direction with the fourth actuator AC4. In this way, the spindle unit MU facilitates the transfer of the second sub-collet SC2 from the second gripping mechanism GM2 to the first gripping mechanism GM1.

[0066] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 along the first movable axis DX1 toward the Y1 side (left), as indicated by the arrow AR16 in the 16th state ST16.

[0067] Subsequently, the spindle unit MU (detachable mechanism AD) drives the second actuator AC2 to swing the arm AP downward around the first movement axis DX1, as indicated by the arrow AR17 in the 17th state ST17. Specifically, the spindle unit MU (detachable mechanism AD) swings the arm AP downward around the first movement axis DX1 until the central axis GX1 of the first gripping mechanism GM1, which is fixed to the tip of the arm AP, and the rotation axis MX of the spindle MS (central axis SX2 of the second sub-collet SC2) coincide (become aligned in the same line).

[0068] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y2 side (right), as indicated by arrow AR18 in the 18th state ST18. As a result, the first gripping mechanism GM1 is able to push the second sub-collet SC2 into the main collet MC. Then, the first gripping mechanism GM1 releases the second sub-collet SC2 by opening a pair of claws in the front-rear direction with the third actuator AC3.

[0069] Subsequently, the spindle unit MU (detachment mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y1 side (left), as shown by arrow AR19 in state ST19 of Figure 11. As a result, the spindle unit MU (detachment mechanism AD) is able to separate the first gripping mechanism GM1 from the second sub-collet SC2 which is fitted into the main collet MC.

[0070] Subsequently, the spindle unit MU (detachable mechanism AD) drives the second actuator AC2 to swing the arm AP upward around the first movement axis DX1, as indicated by arrow AR20 in the 20th state ST20. Specifically, the spindle unit MU (detachable mechanism AD) swings the arm AP upward around the first movement axis DX1 until it reaches the position in the second state ST2 in Figure 6.

[0071] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y2 side (right), as indicated by arrow AR21 in the 21st state ST21. Specifically, the spindle unit MU (detachable mechanism AD) moves the first movable assembly MA1 to the Y2 side (right) until it reaches the position in the first state ST1 in Figure 6. In this way, the spindle unit MU can replace the first sub-collet SC1 that was attached to the spindle MS with the second sub-collet SC2.

[0072] Next, we will describe another movement of the spindle unit MU with reference to Figures 12 to 14. Each of Figures 12 to 14 is a perspective view of the spindle unit MU. Specifically, Figure 12 shows the four states of the spindle unit MU (first state ST51 to fourth state ST54), Figure 13 shows the three states of the spindle unit MU (fifth state ST55 to seventh state ST57), and Figure 14 shows the four states of the spindle unit MU (eighth state ST58 to eleventh state ST61).

[0073] In the illustrated example, when a washer WS, which is an example of a finished workpiece held by a sub-collet SC attached to the spindle MS, is placed into the housing box SB, the state of the spindle unit MU transitions in the following order: first state ST51, second state ST52, ..., ninth state ST59, tenth state ST60, and eleventh state ST61.

[0074] In the initial state, the first state ST51, the spindle unit MU (detachable mechanism AD) has its base BP retracted to the Y2 side (right side) of the partition wall PW so that the through hole HL formed in the partition wall PW can be closed by the cover LD. Also, a sub-collet SC (first sub-collet SC1) is attached to the spindle MS, and a washer WS is gripped by the sub-collet SC (first sub-collet SC1).

[0075] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y1 side (left), as indicated by the arrow AR51 in the second state ST52.

[0076] Subsequently, the spindle unit MU (detachable mechanism AD) drives the second actuator AC2 to swing the arm AP downward around the first movement axis DX1, as indicated by the arrow AR52 in the third state ST53. Specifically, the spindle unit MU (detachable mechanism AD) swings the arm AP downward around the first movement axis DX1 until the central axis GX1 of the first gripping mechanism GM1, which is fixed to the tip of the arm AP, and the rotation axis MX of the spindle MS (central axis SX1 of the first sub-collet SC1) coincide (become aligned in the same line).

[0077] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y2 side (right), as indicated by arrow AR53 in the fourth state ST54. As a result, the first gripping mechanism GM1 can position a pair of claws around the washer WS, which is gripped by the first sub-collet SC1 mounted on the main collet MC. The first gripping mechanism GM1 then grips the washer WS using the force generated by the third actuator AC3.

[0078] Subsequently, the spindle unit MU (detachment mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y1 side (left), as shown by arrow AR54 in the fifth state ST55 in Figure 13. As a result, the first gripping mechanism GM1 is able to pull out the washer WS, which is gripped by the first sub-collet SC1 mounted on the main collet MC, from the first sub-collet SC1.

[0079] Subsequently, the spindle unit MU (detachable mechanism AD) drives the second actuator AC2 to swing the arm AP upward around the first movement axis DX1, as indicated by the arrow AR55 in the sixth state ST56. Specifically, the spindle unit MU (detachable mechanism AD) swings the arm AP upward around the first movement axis DX1 until it reaches the position in the second state ST52 in Figure 12.

[0080] Subsequently, the spindle unit MU (detachable mechanism AD) drives the first actuator AC1 to move the first movable assembly MA1 to the Y2 side (right), as indicated by the arrow AR56 in the seventh state ST57. Specifically, the spindle unit MU (detachable mechanism AD) moves the first movable assembly MA1 to the Y2 side (right) until it reaches the position in the first state ST51 in Figure 12. As a result, the first movable assembly MA1 can face the second gripping mechanism GM2, which has a pair of claws that open and close in the front-to-back direction, with the first gripping mechanism GM1 having a pair of claws that open and close in the up-and-down direction. That is, the second gripping mechanism GM2 can position its pair of claws around the washer WS being gripped by the first gripping mechanism GM1. The second gripping mechanism GM2 then grips the washer WS using the force generated by the fourth actuator AC4. After the washer WS is gripped by the second gripping mechanism GM2, the first gripping mechanism GM1 releases the washer WS by opening a pair of claws vertically using the third actuator AC3. In this way, the spindle unit MU realizes the transfer of the washer WS from the first gripping mechanism GM1 to the second gripping mechanism GM2.

[0081] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 along the third moving axis DX3 to the Y2 side (right), as shown by arrow AR57 in the eighth state ST58 in Figure 14. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y2 side (right) until the Y coordinate (position in the Y-axis direction) of the second gripping mechanism GM2 (washer WS) matches the Y coordinate of the thickness measuring mechanism TM. After that, the spindle unit MU (transport mechanism CD) works in cooperation with the thickness measuring mechanism TM to perform a process (thickness measurement process) to measure the thickness of the washer WS. The thickness measurement process will be described later.

[0082] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 further to the Y2 side (right) along the third moving axis DX3, as indicated by the arrow AR58 in the ninth state ST59. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y2 side (right) until the Y coordinate (position in the Y-axis direction) of the second gripping mechanism GM2 (washer WS) coincides with the Y coordinate of the completed work release position, which is set directly above the storage box SB.

[0083] Subsequently, the spindle unit MU (transport mechanism CD) drives the seventh actuator AC7 to move the second movable assembly MA2 toward the Z2 side (downward) along the fourth moving axis DX4, as indicated by the arrow AR59 in the tenth state ST60. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 toward the Z2 side (downward) until the Z coordinate (position in the Z-axis direction) of the second gripping mechanism GM2 (washer WS) coincides with the Z coordinate of the completed workpiece release position.

[0084] Subsequently, the second gripping mechanism GM2 releases the washer WS by opening the pair of claws in the front-rear direction using the fourth actuator AC4, as shown in the eleventh state ST61. In this way, the spindle unit MU can place the washer WS into the housing box SB.

[0085] Next, with reference to Figure 15, the measurement of the thickness of the washer WS as a finished workpiece using the thickness measurement mechanism TM will be explained. Figure 15 is a perspective view of the second movable assembly MA2 and the thickness measurement mechanism TM. In the illustrated example, the thickness measurement mechanism TM consists of a base PD, an eighth actuator AC8, a third movable assembly MA3, a first displacement sensor SR1, and a second displacement sensor SR2. Note that in Figure 15, a dot pattern is added to the third movable assembly MA3 for clarity of explanation.

[0086] The base PD is a component fixed to the frame of the machine tool 100. The eighth actuator AC8 and the fixed wall 50 are fixed to the base PD, and the third movable assembly MA3 is slidably mounted to it.

[0087] The fixed wall portion 50 is configured such that the Y1 end face (left end face) of the finished workpiece to be measured for thickness is pressed against the Y2 end face (right end face). The fixed wall portion 50 also has a through hole 50H through which the tip (Y2 end, right end) of the first displacement sensor SR1 is inserted.

[0088] The eighth actuator AC8 is an actuator that moves the third movable assembly MA3 relative to the base PD along the fifth movable axis DX5, which is parallel to the axial direction (Y-axis direction) of the main spindle MS. In the illustrated example, the eighth actuator AC8 is a ball screw driven electric actuator. However, the eighth actuator AC8 may be any other actuator.

[0089] The third movable assembly MA3 is a component that is mounted to the base PD so as to be movable along the fifth movable axis DX5. In the illustrated example, the movable wall portion 51 is fixed to the third movable assembly MA3.

[0090] The movable wall portion 51 is positioned opposite the fixed wall portion 50, and a movable pin 51P extending along the Y-axis direction corresponding to the through hole 50H of the fixed wall portion 50 is fixed to it.

[0091] The thickness measuring mechanism TM can operate the first displacement sensor SR1 and the second displacement sensor SR2 while the finished workpiece (washer WS) is sandwiched between the Y2 end face of the fixed wall portion 50 and the Y1 end face of the movable pin 51P.

[0092] The first displacement sensor SR1 and the second displacement sensor SR2 are sensors for measuring the position of the Y1 side end face and the Y2 side end face of the finished workpiece (washer WS). In the illustrated example, the first displacement sensor SR1 and the second displacement sensor SR2 are contact-type digital displacement sensors. However, the first displacement sensor SR1 and the second displacement sensor SR2 may be any displacement sensor, such as a non-contact type displacement sensor.

[0093] In the illustrated example, the first displacement sensor SR1 is configured such that its tip (right end) passes through the through-hole 50H of the fixed wall 50 and contacts the Y1-side end face of the finished workpiece (washer WS). The first displacement sensor SR1 is also configured such that its tip (right end) contacts the third movable assembly MA3. The controller CTR can directly measure the position of the Y1-side end face of the finished workpiece (washer WS) based on the output of the first displacement sensor SR1, and indirectly measure the position of the Y2-side end face of the finished workpiece (washer WS) based on the output of the second displacement sensor SR2. The controller CTR can then calculate the thickness of the finished workpiece (washer WS) based on the positions of the Y1-side end face and the Y2-side end face.

[0094] Furthermore, the machine tool 100 is configured to measure the thickness of multiple locations on the finished washer WS. This is to determine whether the variation in the thickness of the washer WS falls within a predetermined range.

[0095] Specifically, the controller CTR is configured to measure the thickness of the washer WS at the first measurement point MP1 and the second measurement point MP2, as shown in Figure 16. Figure 16 shows the positional relationship between the fixed wall portion 50 and the washer WS when measuring the thickness of the washer WS. Specifically, the left view of Figure 16 (upper left and lower left views) is a right side view of the fixed wall portion 50 and the washer WS, and the right view of Figure 16 (upper right and lower right views) is a front view of the fixed wall portion 50 and the washer WS. Furthermore, the upper view of Figure 16 (upper left and upper right views) shows the measurement of the thickness of the washer WS at the first measurement point MP1, and the lower view of Figure 16 (lower left and lower right views) shows the measurement of the thickness of the washer WS at the second measurement point MP2. Note that in Figure 16, for clarity, other components of the thickness measurement mechanism TM other than the fixed wall portion 50 are omitted from the illustration.

[0096] Next, with reference to Figures 17 to 20, the movement of the second movable assembly MA2 and the thickness measuring mechanism TM when measuring the thickness of the finished workpiece (washer WS) will be explained. Each of Figures 17 to 20 is a perspective view of the second movable assembly MA2 and the thickness measuring mechanism TM. Specifically, each of Figures 17 to 20 is an enlarged perspective view of the area R2 enclosed by the dashed line shown in Figure 14. Furthermore, Figure 17 shows the four states of the second movable assembly MA2 and the thickness measuring mechanism TM (first state ST81 to fourth state ST84), Figure 18 shows the four states of the second movable assembly MA2 and the thickness measuring mechanism TM (fifth state ST85 to eighth state ST88), Figure 19 shows the four states of the second movable assembly MA2 and the thickness measuring mechanism TM (ninth state ST89 to twelfth state ST92), and Figure 20 shows the two states of the second movable assembly MA2 and the thickness measuring mechanism TM (thirteenth state ST93 and fourteenth state ST94).

[0097] In the illustrated example, when measuring the thickness of the washer WS, the states of the second movable assembly MA2 and the thickness measuring mechanism TM transition in the following order: first state ST81, second state ST82, ..., thirteenth state ST93, and fourteenth state ST94.

[0098] In the initial state ST81 shown in Figure 17, the second movable assembly MA2 is positioned such that, in a plan view, the second gripping mechanism GM2 is located between the fixed wall portion 50 and the movable pin 51P.

[0099] Subsequently, the spindle unit MU (transport mechanism CD) drives the seventh actuator AC7 to move the second movable assembly MA2 toward the Z2 side (downward) along the fourth moving axis DX4, as indicated by the arrow AR81 in the second state ST82. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 toward the Z2 side (downward) until the first measurement point MP1 of the washer WS, which is gripped by the second gripping mechanism GM2, coincides with the center of the through hole 50H formed in the fixed wall portion 50, as shown in the upper diagram of Figure 16.

[0100] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 to the Y1 side (left), as indicated by the arrow AR82 in the third state ST83. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y1 side (left) until the Y1 side end face (left end face) of the washer WS, which is gripped by the second gripping mechanism GM2, comes into contact with the Y2 side end face (right end face) of the fixed wall portion 50.

[0101] Subsequently, the spindle unit MU (thickness measuring mechanism TM) drives the eighth actuator AC8 to move the third movable assembly MA3 to the Y1 side (left), as indicated by the arrow AR83 in the fourth state ST84. Specifically, the spindle unit MU (thickness measuring mechanism TM) moves the third movable assembly MA3 to the Y1 side (left) until the Y2 side end face (right end face) of the washer WS, which is gripped by the second gripping mechanism GM2, comes into contact with the Y1 side end face (left end face) of the movable pin 51P.

[0102] Subsequently, the spindle unit MU (thickness measuring mechanism TM) moves the Y2-side end (right end) of the first displacement sensor SR1 to the Y2 side (right), as indicated by arrow AR84 in the fifth state ST85 of Figure 18, passing it through the through hole 50H of the fixed wall portion 50 and bringing it into contact with the Y1-side end face (left end face) of the washer WS. Also, the spindle unit MU (thickness measuring mechanism TM) moves the Y2-side end (right end) of the second displacement sensor SR2 to the Y2 side (right), as indicated by arrow AR85 in the fifth state ST85, bringing it into contact with a part of the third movable assembly MA3. This movement allows the controller CTR to measure the thickness of the first measurement point MP1 of the washer WS.

[0103] Subsequently, the spindle unit MU (thickness measuring mechanism TM) drives the eighth actuator AC8 to move the third movable assembly MA3 to the Y2 side (right), as indicated by the arrow AR86 in the sixth state ST86. Specifically, the spindle unit MU (thickness measuring mechanism TM) moves the third movable assembly MA3 to the Y2 side (right) to the position shown in the third state ST83 in Figure 17.

[0104] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 to the Y2 side (right), as indicated by arrow AR87 in the seventh state ST87. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y2 side (right) to the position shown in the second state ST82 in Figure 17. As a result, the washer WS separates from the fixed wall portion 50.

[0105] Subsequently, the spindle unit MU (transport mechanism CD) drives the seventh actuator AC7 to move the second movable assembly MA2 toward the Z2 side (downward) along the fourth moving axis DX4, as indicated by the arrow AR88 in the eighth state ST88. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 toward the Z2 side (downward) until the second measurement point MP2 of the washer WS, which is gripped by the second gripping mechanism GM2, coincides with the center of the through hole 50H formed in the fixed wall portion 50, as shown in the lower diagram of Figure 16.

[0106] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 to the Y1 side (left), as shown by the arrow AR89 in the ninth state ST89 in Figure 19. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y1 side (left) until the Y1 side end face (left end face) of the washer WS, which is gripped by the second gripping mechanism GM2, comes into contact with the Y2 side end face (right end face) of the fixed wall portion 50.

[0107] Subsequently, the spindle unit MU (thickness measuring mechanism TM) drives the eighth actuator AC8 to move the third movable assembly MA3 to the Y1 side (left), as indicated by the arrow AR90 in the tenth state ST90. Specifically, the spindle unit MU (thickness measuring mechanism TM) moves the third movable assembly MA3 to the Y1 side (left) until the Y2 side end face (right end face) of the washer WS, which is gripped by the second gripping mechanism GM2, comes into contact with the Y1 side end face (left end face) of the movable pin 51P.

[0108] Subsequently, the spindle unit MU (thickness measuring mechanism TM) moves the Y2-side end (right end) of the first displacement sensor SR1 to the Y2 side (right), as indicated by arrow AR91 in the 11th state ST91, passing it through the through hole 50H of the fixed wall portion 50 and bringing it into contact with the Y1-side end face (left end face) of the washer WS. Also, the spindle unit MU (thickness measuring mechanism TM) moves the Y2-side end (right end) of the second displacement sensor SR2 to the Y2 side (right), as indicated by arrow AR92 in the 11th state ST91, bringing it into contact with a part of the third movable assembly MA3. This movement allows the controller CTR to measure the thickness of the second measurement point MP2 of the washer WS.

[0109] Subsequently, the spindle unit MU (thickness measuring mechanism TM) drives the eighth actuator AC8 to move the third movable assembly MA3 to the Y2 side (right), as indicated by arrow AR93 in the twelfth state ST92. Specifically, the spindle unit MU (thickness measuring mechanism TM) moves the third movable assembly MA3 to the Y2 side (right) to the position in the ninth state ST89.

[0110] Subsequently, the spindle unit MU (transport mechanism CD) drives the sixth actuator AC6 to move the second movable assembly MA2 to the Y2 side (right), as shown by arrow AR94 in the 13th state ST93 in Figure 20. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 to the Y2 side (right) to the position shown in the 8th state ST88 in Figure 18. As a result, the washer WS separates from the fixed wall portion 50.

[0111] Subsequently, the spindle unit MU (transport mechanism CD) drives the seventh actuator AC7 to move the second movable assembly MA2 toward the Z1 side (upwards) along the fourth moving axis DX4, as indicated by the arrow AR95 in the 14th state ST94. Specifically, the spindle unit MU (transport mechanism CD) moves the second movable assembly MA2 toward the Z1 side (upwards) to the position in the first state ST81 in Figure 17, that is, the position in the eighth state ST58 in Figure 14.

[0112] In this way, the thickness measurement mechanism TM enables the controller CTR to measure the thickness of the washer WS at the first measurement point MP1 and the second measurement point MP2, respectively.

[0113] Next, referring to Figure 21, we will explain the process by which the controller CTR replaces the first sub-collet SC1, which is attached to the main collet MC mounted on the spindle MS, with the second sub-collet SC2 (hereinafter referred to as the "sub-collet replacement process"). Figure 21 is a flowchart showing an example of the sub-collet replacement process. The controller CTR repeatedly performs this sub-collet replacement process at a predetermined control cycle.

[0114] First, the controller CTR determines whether or not it has received a sub-collet replacement command (step PR1). In the illustrated example, the controller CTR determines whether or not it has received a sub-collet replacement command from an external source via communication. The sub-collet replacement command may also be entered by an operator near the machine tool 100 via an input device such as a touch panel attached to the controller CTR.

[0115] If the controller CTR determines that it has not received a sub-collet replacement command (NO in step PR1), it terminates the current sub-collet replacement process. On the other hand, if it determines that it has received a sub-collet replacement command (YES in step PR1), the controller CTR removes the old sub-collet from the main collet MC (step PR2). The "old sub-collet" is the sub-collet SC attached to the main collet MC mounted on the spindle MS before replacement, and in the illustrated example, it is the first sub-collet SC1. Specifically, the controller CTR operates the spindle unit MU (attachment / detachment mechanism AD and first gripping mechanism GM1) from the second state ST2 in Figure 6 to the fifth state ST5 in Figure 7, and removes the first sub-collet SC1 from the main collet MC. The controller CTR can also understand the status of each mechanism, such as the attachment / detachment mechanism AD, the transport mechanism CD, the collet holder moving mechanism CM, the first gripping mechanism GM1, and the second gripping mechanism GM2, based on information stored in a volatile memory device or a non-volatile memory device. In other words, the information stored in the volatile memory device or non-volatile memory device includes information such as the position of the collet holder CH, the position of the first movable assembly MA1, and the position of the second movable assembly MA2.

[0116] Subsequently, the controller CTR transfers the old sub-collet from the first gripping mechanism GM1 to the second gripping mechanism GM2 (step PR3). In the illustrated example, the controller CTR operates the spindle unit MU (attachment / detachment mechanism AD, first gripping mechanism GM1, and second gripping mechanism GM2) as shown from the fifth state ST5 to the seventh state ST7 in Figure 7. Then, the controller CTR transfers the first sub-collet SC1 from the first gripping mechanism GM1 to the second gripping mechanism GM2.

[0117] Subsequently, the controller CTR stores the old sub-collet in the collet holder CH (step PR4). In the illustrated example, the controller CTR operates the spindle unit MU (transport mechanism CD, second gripping mechanism GM2, and collet holder moving mechanism CM) from state ST8 in Figure 7 to state ST10 in Figure 8. Then, the controller CTR stores the first sub-collet SC1, which is the old sub-collet, in the storage space SG1 on the collet holder CH.

[0118] Subsequently, the controller CTR picks up the new sub-collet from the collet holder CH (step PR5). The "new sub-collet" is the replacement sub-collet SC that is newly installed on the main collet MC, and in the illustrated example, it is the second sub-collet SC2. In the illustrated example, the controller CTR operates the spindle unit MU (transport mechanism CD, second gripping mechanism GM2, and collet holder moving mechanism CM) as shown from state 11 ST11 in Figure 8 to state 14 ST14 in Figure 9. The controller CTR then picks up the second sub-collet SC2, which is the new sub-collet, from the storage space SG2 on the collet holder CH. The controller CTR identifies storage spaces SG1 and SG2 from among multiple (15 in the illustrated example) storage spaces on the collet holder CH based on information stored in a volatile memory device or a non-volatile memory device.

[0119] Subsequently, the controller CTR transfers the new sub-collet from the second gripping mechanism GM2 to the first gripping mechanism GM1 (step PR6). In the illustrated example, the controller CTR operates the spindle unit MU (transport mechanism CD, first gripping mechanism GM1, and second gripping mechanism GM2) as shown in state 14 ST14 in Figure 9 and state 15 ST15 in Figure 10. Then, the controller CTR transfers the second sub-collet SC2 from the second gripping mechanism GM2 to the first gripping mechanism GM1.

[0120] Subsequently, the controller CTR installs the new sub-collet onto the main collet MC (step PR7). In the illustrated example, the controller CTR operates the spindle unit MU (attachment / detachment mechanism AD and first gripping mechanism GM1) as shown from state 16 ST16 to state 18 ST18 in Figure 10, and fits the second sub-collet SC2 onto the main collet MC.

[0121] In this way, the controller CTR can replace the old sub-collet (first sub-collet SC1) that was attached to the main collet MC with the new sub-collet (second sub-collet SC2).

[0122] Next, referring to Figure 22, we will explain the process by which the controller CTR measures the thickness of the finished workpiece (washer WS) (hereinafter referred to as the "thickness measurement process"). Figure 22 is a flowchart showing an example of the flow of the thickness measurement process. The controller CTR repeatedly executes this thickness measurement process at a predetermined control cycle.

[0123] First, the controller CTR determines whether or not machining of the workpiece is complete (step PR11). In the illustrated example, the controller CTR determines that machining of the workpiece is complete when the machining of the bar stock BR ​​is finished, and the finished workpiece (washer WS) is produced.

[0124] If it is determined that machining on the workpiece is not complete (NO in step PR11), the controller CTR terminates the thickness measurement process. On the other hand, if it is determined that machining on the workpiece is complete (YES in step PR11), the controller CTR removes the finished workpiece from the sub-collet SC (step PR12). In the illustrated example, the controller CTR operates the spindle unit MU (attachment / detachment mechanism AD and first gripping mechanism GM1) from the second state ST52 in Figure 12 to the fifth state ST55 in Figure 13. The controller CTR then pulls the washer WS, which is the finished workpiece gripped by the sub-collet SC mounted on the main collet MC, from the sub-collet SC.

[0125] Subsequently, the controller CTR transfers the completed workpiece from the first gripping mechanism GM1 to the second gripping mechanism GM2 (step PR13). In the illustrated example, the controller CTR operates the spindle unit MU (attachment / detachment mechanism AD, first gripping mechanism GM1, and second gripping mechanism GM2) as shown from the fifth state ST55 to the seventh state ST57 in Figure 13. Then, the controller CTR transfers the washer WS as the completed workpiece from the first gripping mechanism GM1 to the second gripping mechanism GM2.

[0126] Subsequently, the controller CTR measures the thickness at the first measurement point MP1 of the finished workpiece (step PR14). In the illustrated example, the controller CTR operates the spindle unit MU (transport mechanism CD, second gripping mechanism GM2, and thickness measurement mechanism TM) from the first state ST81 in Figure 17 to the fifth state ST85 in Figure 18. The controller CTR then measures the thickness at the first measurement point MP1 (see upper diagram in Figure 16) of the washer WS as the finished workpiece. The controller CTR can determine the state of the second gripping mechanism GM2 and the thickness measurement mechanism TM based on information stored in a volatile memory device or a non-volatile memory device. Specifically, the information stored in the volatile memory device or a non-volatile memory device includes information such as the position of the second movable assembly MA2 and the position of the third movable assembly MA3.

[0127] Subsequently, the controller CTR measures the thickness at the second measurement point MP2 in the finished workpiece (step PR15). In the illustrated example, the controller CTR operates the spindle unit MU (transport mechanism CD, second gripping mechanism GM2, and thickness measurement mechanism TM) as shown from the sixth state ST86 in Figure 18 to the eleventh state ST91 in Figure 19. The controller CTR then measures the thickness at the second measurement point MP2 (see lower diagram in Figure 16) in the washer WS as the finished workpiece.

[0128] Subsequently, the controller CTR places the finished workpiece into the storage box SB (step PR16). In the illustrated example, the controller CTR operates the spindle unit MU (transport mechanism CD and second gripping mechanism GM2) as shown from the 8th state ST58 to the 11th state ST61 in Figure 14. Then, the controller CTR places the washer WS, which is the finished workpiece, into the storage box SB.

[0129] In this way, the controller CTR can measure the thickness of the washer WS as a finished workpiece and determine whether the washer WS is defective or not. For example, the controller CTR may determine that the washer WS is defective if the difference between the thickness of the washer WS at the first measurement point MP1 and the thickness of the washer WS at the second measurement point MP2 is greater than or equal to a predetermined value. The controller CTR may also be configured to place the washer WS in a box other than the storage box SB if it determines that the washer WS is defective.

[0130] As described above, the machine tool 100 according to the embodiment of this disclosure includes a spindle MS and a detachable mechanism AD that allows a workpiece to be attached to and detached from an outer collet (main collet MC) attached to the spindle MS, and an inner collet (sub-collet SC) to be attached to and detached from the main collet MC attached to the spindle MS. The detachable mechanism AD has a base BP that is movable along a first moving axis DX1 that extends parallel to the axial direction (Y-axis direction) of the spindle MS, and an arm AP that extends radially outward from the base BP in a circle centered on the first moving axis DX1. The arm AP is configured to be rotatable around the first moving axis DX1. A first gripping mechanism GM1 capable of individually gripping the workpiece and the sub-collet SC is attached to the tip of the arm AP.

[0131] This configuration has the effect of allowing the sub-collet SC to be replaced without moving the spindle MS. Therefore, this configuration has the effect of suppressing the structural complexity of the machine tool 100.

[0132] Furthermore, the machine tool 100 may be equipped with a transport mechanism CD capable of individually transporting the workpiece and sub-collet SC along a second moving axis DX2 parallel to the axial direction (Y-axis direction) of the main spindle MS. The transport mechanism CD may also have a second gripping mechanism GM2 capable of individually gripping the workpiece and sub-collet SC. The first gripping mechanism GM1 may also be configured to grip the sub-collet SC that is being gripped by the second gripping mechanism GM2.

[0133] This configuration has the effect of allowing the first gripping mechanism GM1 to transfer the sub-collet SC or workpiece, which it has pulled out from the main collet MC, to the second gripping mechanism GM2. Therefore, this configuration has the effect of allowing the sub-collet SC or workpiece, which has been pulled out from the main collet MC, to be transported to a location far away from the main collet MC.

[0134] Furthermore, the machine tool 100 may hold a plurality of sub-collets SC such that they are lined up, and may also have a collet holder moving mechanism CM that can move one of the plurality of sub-collets SC to a position where it can be gripped by the second gripping mechanism GM2.

[0135] This configuration allows for the efficient storage of the sub-collet SC pulled from the main collet MC, and also enables the efficient provision of a replacement sub-collet SC. Therefore, this configuration has the effect of reducing the time required to replace the sub-collet SC.

[0136] Furthermore, the machine tool 100 may have a thickness measuring mechanism TM for measuring the thickness of the workpiece.

[0137] This configuration allows for the measurement of the thickness of the workpiece being transported using the same mechanism as the mechanism for transporting the sub-collet SC, resulting in the miniaturization and space-saving of the machine tool 100. Furthermore, this configuration allows for the determination of whether or not a workpiece is defective, thus improving the quality of workpieces processed by the machine tool 100.

[0138] Furthermore, the sub-collet SC may be attached to the main collet MC via an anti-detachment mechanism CP consisting of a metal ball 20 and an O-ring 21, as shown in Figures 2 and 3.

[0139] This configuration has the effect of preventing the sub-collet SC from coming loose from the main collet MC. Therefore, this configuration makes the gripping of the workpiece by the sub-collet SC more reliable, and consequently has the effect of improving the quality of the workpiece processed by the machine tool 100.

[0140] Furthermore, the spindle MS may be provided with an extrusion mechanism PS for pushing out the workpiece located inside the sub-collet SC, as shown in Figures 2 and 4.

[0141] This configuration has the effect of allowing the workpiece held by the sub-collet SC to be easily removed without having to pull out the sub-collet SC. Therefore, this configuration can prevent the sub-collet SC from being accidentally pulled out of the main collet MC, and consequently, it has the effect of eliminating the time required to reattach the sub-collet SC to the main collet MC if it has been accidentally pulled out.

[0142] Furthermore, the machine tool 100 may have a computer (controller CTR) that controls the movement of the attachment / detachment mechanism AD, the first gripping mechanism GM1, the second gripping mechanism GM2, and the transport mechanism CD. The controller CTR may operate the attachment / detachment mechanism AD to remove the inner collet (first sub-collet SC1) from the outer collet (main collet MC) mounted on the spindle MS, as shown from the first state ST1 in Figure 6 to the fifth state ST5 in Figure 7. The controller CTR may also operate the first gripping mechanism GM1 and the second gripping mechanism to transfer the removed first sub-collet SC1, as shown from the sixth state ST6 to the seventh state ST7 in Figure 7. Furthermore, as shown in the eighth state ST8 in Figure 7 to the fourteenth state ST14 in Figure 9, the controller CTR may operate the second gripping mechanism GM2 and the transport mechanism CD to store the removed first sub-collet SC1 in a predetermined position (storage space SG1) and pick up another inner collet (second sub-collet SC2) located in another predetermined position (storage space SG2). Also, as shown in the fifteenth state ST15 in Figure 10, the controller CTR may operate the first gripping mechanism GM1 and the second gripping mechanism GM2 to transfer the picked-up second sub-collet SC2. Furthermore, as shown in the sixteenth state ST16 to the eighteenth state ST18 in Figure 10, the controller CTR may operate the attachment / detachment mechanism AD to attach the second sub-collet SC2 to the main collet MC mounted on the spindle MS.

[0143] With this configuration, the machine tool 100 can automatically operate the attachment / detachment mechanism AD, the first gripping mechanism GM1, the second gripping mechanism GM2, and the transport mechanism CD, and automatically replace the sub-collet SC (first sub-collet SC1) that was mounted on the main collet MC with another sub-collet SC (second sub-collet SC2) that was housed in the collet holder CH. In addition, the machine tool 100 can automatically house the sub-collet SC (first sub-collet SC1) that was mounted on the main collet MC into the collet holder CH.

[0144] Furthermore, the machine tool 100 may have a computer (controller CTR) that controls the movement of the attachment / detachment mechanism AD, the first gripping mechanism GM1, the second gripping mechanism GM2, the transport mechanism CD, and the thickness measuring mechanism TM for measuring the thickness of the workpiece (washer WS). The controller CTR may operate the attachment / detachment mechanism AD to remove the washer WS from the outer collet (main collet MC) mounted on the spindle MS, as shown from the first state ST51 in Figure 12 to the fifth state ST55 in Figure 13. The controller CTR may also operate the first gripping mechanism GM1 and the second gripping mechanism GM2 to transfer the removed washer WS, as shown from the sixth state ST56 to the seventh state ST57 in Figure 13. The controller CTR may also operate the transport mechanism CD and the thickness measuring mechanism TM to measure the thickness of the washer WS, as shown from the first state ST81 in Figure 17 to the eleventh state ST91 in Figure 19.

[0145] With this configuration, the machine tool 100 can automatically operate the attachment / detachment mechanism AD, the first gripping mechanism GM1, the second gripping mechanism GM2, the transport mechanism CD, and the thickness measuring mechanism TM, thereby automatically measuring the thickness of the washer WS. Furthermore, the machine tool 100 can automatically determine whether or not the washer WS is defective.

[0146] Furthermore, as shown in Figure 21, the control method for the machine tool 100 according to the embodiment of this disclosure includes the steps of: the controller CTR operating the attachment / detachment mechanism AD to remove the inner collet (first sub-collet SC1) from the outer collet (main collet MC) mounted on the spindle MS (see step PR2); the controller CTR operating the first gripping mechanism GM1 and the second gripping mechanism GM2 to transfer the removed first sub-collet SC1 (see step PR3); and the controller CTR storing the removed first sub-collet SC1 in a predetermined position and elsewhere The process includes the steps of: operating the second gripping mechanism GM2 and the transport mechanism CD to pick up another internal collet (second sub-collet SC2) that is in a fixed position (see steps PR4 and PR5); the controller CTR operating the first gripping mechanism GM1 and the second gripping mechanism GM2 to transfer the picked-up second sub-collet SC2 (see step PR6); and the controller CTR operating the attachment / detachment mechanism AD to attach the second sub-collet SC2 to the main collet MC mounted on the spindle MS (see step PR7).

[0147] This control method has the effect of allowing the sub-collet SC to be replaced without operating the machine tool 100 or moving the spindle MS of the machine tool 100. Therefore, this control method has the effect of allowing the machine tool 100 to perform the function of automatically replacing the sub-collet SC while suppressing the complexity of the machine tool 100's structure.

[0148] Furthermore, the program used in the machine tool 100 according to the embodiment of this disclosure includes, as shown in Figure 21, a process to operate the attachment / detachment mechanism AD to remove the inner collet (first sub-collet SC1) from the outer collet (main collet MC) mounted on the spindle MS (see step PR2), a process to operate the first gripping mechanism GM1 and the second gripping mechanism GM2 to transfer the removed first sub-collet SC1 (see step PR3), and a process to store the removed first sub-collet SC1 in a predetermined position and another predetermined position The controller CTR is instructed to perform the following operations: operate the second gripping mechanism GM2 and the transport mechanism CD to pick up the inner collet (second sub-collet SC2) (see steps PR4 and PR5); operate the first gripping mechanism GM1 and the second gripping mechanism GM2 to transfer the picked-up second sub-collet SC2 (see step PR6); and operate the attachment / detachment mechanism AD to attach the second sub-collet SC2 to the main collet MC mounted on the spindle MS (see step PR7).

[0149] This program, when used in machine tool 100, has the effect of allowing the sub-collet SC to be replaced without moving the spindle MS of machine tool 100. Therefore, this program has the effect of enabling machine tool 100 to perform the function of automatically replacing the sub-collet SC while suppressing the complexity of the machine tool 100's structure.

[0150] Preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the embodiments described above. Various modifications and substitutions can be applied to the embodiments described above without departing from the scope of the present invention. Furthermore, each of the features described with reference to the embodiments described above may be combined as appropriate, as long as they do not conflict technically. [Explanation of symbols]

[0151] 10...Pin 11...Main body component 11F...Flange section 11G...Groove section 11H...Through hole 11S...Step section 12...Movable component 12E...Tip section 12F...Flange section 12G...Groove section 20...Metal ball 21...O-ring 22...Collet connecting component 22H...Through hole 22G1...First groove section 22G2...Second groove section 30...Cylindrical component 30N...Inner ring section 30P...Pin 30T...Conical protrusion 31...Bolt 32...Flange component 50...Fixed wall section 50H...Through hole 51...Movable wall section 51P...Movable pin 100...Machine tool AC1...First actuator AC2...Second actuator AC3...Third actuator AC4...Fourth actuator AC5...Fifth actuator AC6...Sixth actuator AC7...Seventh actuator AC8...Eighth actuator AD...Detachable mechanism AP...Arm section BP...Base BR...Rod CD...Transport mechanism CG...Groove section CH...Collet holder CM...Collet holder movement mechanism CP...Anti-slip mechanism CR...Collet receiving member CTR...Controller GM1...First gripping mechanism GM2...Second gripping mechanism LD...Lid MA1...First movable assembly MA2...Second movable assembly MA3...Third movable assembly MC...Main collet MS...Spindle MU...Spindle unit PD...Base PH...Pin hole PS...Extrusion mechanism SB...Housing box SC...Sub-collet SR1...First displacement sensor SR2...Second displacement sensor TM...Thickness measuring mechanism WS...Washer

Claims

1. The main shaft, The system includes a detachable mechanism that allows a workpiece to be attached to and detached from an outer collet mounted on the spindle, and an inner collet to be attached to and detached from the outer collet mounted on the spindle, The attachment / detachment mechanism has a base portion that is movable along a first movement axis that extends parallel to the axial direction of the main shaft, and an arm portion that extends radially outward from the base portion in a circle centered on the first movement axis. The arm portion is configured to be rotatable around the first movable axis, A first gripping mechanism capable of individually gripping the workpiece and the inner collet is attached to the tip of the arm portion. A machine tool characterized by the following features.

2. The system includes a transport mechanism capable of individually transporting the workpiece and the inner collet along a second moving axis parallel to the axial direction of the main spindle, The transport mechanism has a second gripping mechanism capable of individually gripping the workpiece and the inner collet. The first gripping mechanism is configured to grip the inner collet which is being gripped by the second gripping mechanism. The machine tool according to claim 1.

3. The collet holder moving mechanism holds the plurality of inner collets so that they are aligned, and moves one of the plurality of inner collets to a position where it can be gripped by the second gripping mechanism. The machine tool according to claim 2.

4. Having a thickness measuring mechanism for measuring the thickness of the workpiece, The machine tool according to claim 2.

5. The inner collet is attached to the outer collet via an anti-detachment mechanism consisting of a metal ball and an O-ring. The machine tool according to claim 1.

6. The spindle is provided with an extrusion mechanism for pushing out the workpiece located inside the inner collet. The machine tool according to claim 1.

7. The system includes a computer that controls the movement of the attachment / detachment mechanism, the first gripping mechanism, the second gripping mechanism, and the transport mechanism, respectively. The aforementioned computer, The attachment / detachment mechanism is operated to remove the inner collet from the outer collet mounted on the spindle. The first gripping mechanism and the second gripping mechanism are operated to transfer the removed inner collet. The second gripping mechanism and the transporting mechanism are operated to store the removed inner collet in a predetermined position and to pick up another inner collet located in another predetermined position. The first gripping mechanism and the second gripping mechanism are operated to transfer the picked-up other inner collet, The attachment / detachment mechanism is operated to attach the other inner collet to the outer collet mounted on the spindle. The machine tool according to claim 2.

8. The system includes a computer that controls the movement of the attachment / detachment mechanism, the first gripping mechanism, the second gripping mechanism, the transport mechanism, and the thickness measuring mechanism for measuring the thickness of the workpiece. The aforementioned computer, The attachment / detachment mechanism is operated to remove the workpiece from the outer collet mounted on the spindle. The first gripping mechanism and the second gripping mechanism are operated to transfer the removed workpiece, The transport mechanism and the thickness measuring mechanism are operated to measure the thickness of the workpiece. The machine tool according to claim 2.

9. A method for controlling a machine tool, The aforementioned machine tool is The main shaft, A detachable mechanism that allows a workpiece to be attached to and detached from an outer collet mounted on the spindle, and allows an inner collet to be attached to and detached from the outer collet mounted on the spindle, The system includes a transport mechanism capable of individually transporting the workpiece and the inner collet along a second moving axis parallel to the axial direction of the main spindle, The attachment / detachment mechanism has a base portion that is movable along a first movement axis that extends parallel to the axial direction of the main shaft, and an arm portion that extends radially outward from the base portion in a circle centered on the first movement axis. The arm portion is configured to be rotatable around the first movable axis, A first gripping mechanism capable of individually gripping the workpiece and the inner collet is attached to the tip of the arm portion. The transport mechanism has a second gripping mechanism capable of individually gripping the workpiece and the inner collet. The first gripping mechanism is configured to grip the inner collet which is being gripped by the second gripping mechanism, The control method is The computer operates the attachment / detachment mechanism to remove the inner collet from the outer collet mounted on the spindle. The computer operates the first gripping mechanism and the second gripping mechanism to transfer the removed inner collet. The computer operates the second gripping mechanism and the transport mechanism to store the removed inner collet in a predetermined position and to pick up another inner collet located in another predetermined position. The computer operates the first gripping mechanism and the second gripping mechanism to transfer the other inner collet that has been picked up, and The computer operates the attachment / detachment mechanism to attach the other inner collet to the outer collet mounted on the spindle, A method for controlling machine tools.

10. A program used in machine tools, The aforementioned machine tool is The main shaft, A detachable mechanism that allows a workpiece to be attached to and detached from an outer collet mounted on the spindle, and allows an inner collet to be attached to and detached from the outer collet mounted on the spindle, The system includes a transport mechanism capable of individually transporting the workpiece and the inner collet along a second moving axis parallel to the axial direction of the main spindle, The attachment / detachment mechanism has a base portion that is movable along a first movement axis that extends parallel to the axial direction of the main shaft, and an arm portion that extends radially outward from the base portion in a circle centered on the first movement axis. The arm portion is configured to be rotatable around the first movable axis, A first gripping mechanism capable of individually gripping the workpiece and the inner collet is attached to the tip of the arm portion. The transport mechanism has a second gripping mechanism capable of individually gripping the workpiece and the inner collet. The first gripping mechanism is configured to grip the inner collet which is being gripped by the second gripping mechanism, This program is A process of operating the attachment / detachment mechanism to remove the inner collet from the outer collet mounted on the spindle, A process of operating the first gripping mechanism and the second gripping mechanism to transfer the removed inner collet, A process of operating the second gripping mechanism and the transporting mechanism to store the removed inner collet in a predetermined position and to pick up another inner collet located in another predetermined position, A process of operating the first gripping mechanism and the second gripping mechanism to transfer the picked-up other inner collet, and, The computer is instructed to perform the process of operating the attachment / detachment mechanism to attach the other inner collet to the outer collet mounted on the spindle. program.

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