Numerical value controller, method for control, and program

Abstract

To provide a numerical value controller, a method for control, and a program which can reduce power consumption of a servo motor for driving a tool magazine.SOLUTION: A numerical value controller detects the position of a main shaft in the direction of a Z-axis by an encoder of a Z-axial motor. The numerical value controller interrupts power supply to a magazine motor in a stand-by state in which a tool magazine is not operated. When the numerical value controller issues an order to exchange tools, the main shaft moves from a processing region to a tool exchange region. The numerical controller resumes power supply to the magazine motor on the condition that the presence of the main shaft in the tool exchange region is detected, when a tool on the main shaft is exchanged on the basis of the tool exchange order.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a numerical control device, a control method, and a program.

Background Art

[0002] Patent Document 1 discloses a tool changer capable of reducing the power consumption of a servo motor that rotates a tool magazine. The tool changer exchanges tools between the tool magazine and the spindle. The tool magazine has a plurality of tool pods and is rotated by a servo motor. The tool magazine is provided with an electromagnetic brake that operates when the power supply to the servo motor is stopped. When the next tool change command is not output even after a predetermined time has elapsed after the tool magazine has been rotated, the tool changer interrupts the power supply to the servo motor and operates the electromagnetic brake. When the next tool change command is output, the tool changer supplies power to the servo motor and stops the operation of the electromagnetic brake.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a tool change command is output, the spindle moves from the machining area for machining the workpiece to the tool change area in order to exchange tools between the tool magazine and the spindle. Since the tool changer resumes the power supply to the servo motor when the tool change command is output, power is consumed in the servo motor while the spindle moves from the machining area to the tool change area.

[0005] An object of the present invention is to provide a numerical control device, a control method, and a program capable of reducing the power consumption of a servo motor that drives a tool magazine.

Means for Solving the Problem

[0006] The numerical control device according to the first aspect of the present invention is a numerical control device that can mount a tool and controls the operation of a machine tool including a spindle movable to a machining area where machining of a workpiece is performed using the tool and a tool changing area where the tool is changed, and a tool magazine capable of loading the tool and transporting the tool mounted on the spindle to a tool changing position by driving a servo motor. In a standby state where the tool magazine is not operated, an interrupting unit that interrupts power supply to the servo motor, a position detecting unit that detects the position of the spindle, and a resuming unit that resumes power supply to the servo motor interrupted by the interrupting unit on the condition that the position detecting unit detects that the spindle is located within the tool changing area.

[0007] When the numerical control device of the first aspect outputs a tool change command, the spindle moves from the machining area to the tool changing area, and the tool magazine operates by driving the servo motor. In the numerical control device, power supply to the servo motor is resumed on the condition that it is detected that the spindle is located within the tool changing area of the spindle. Therefore, the numerical control device can reduce the power consumption of the servo motor as compared with the case where power supply to the servo motor is resumed when the tool change command is output.

[0008] In the numerical control device, the tool magazine is operable when the spindle is located at a specific spindle position within the tool changing area, and the resuming unit may resume power supply to the servo motor on the condition that the position detecting unit detects that the spindle is located at the specific spindle position. In the numerical control device, when the spindle reaches a specific spindle position for operating the tool magazine in the tool changing area, the tool magazine operates by driving the servo motor. Since power supply to the servo motor is resumed immediately before the operation of the tool magazine starts, the numerical control device can further reduce the power consumption of the servo motor.

[0009] In a numerical control device, the interruption unit may interrupt the power supply to the servo motor on the condition that the operation of the tool magazine by the servo motor is completed in a state where the power supply to the servo motor is resumed by the resumption unit. In a numerical control device, the tool magazine conveys a tool mounted on the spindle to a tool change position by driving the servo motor. In the numerical control device, when it is determined that the operation of the tool magazine is completed, the power supply to the servo motor is interrupted. Therefore, the numerical control device can reduce the power consumption of the servo motor as compared with the case where the power supply to the servo motor is performed between when the operation of the tool magazine is completed and when the spindle moves to the machining area.

[0010] In a numerical control device, the interruption unit may interrupt the power supply to the servo motor on the condition that the operation of the tool magazine by the servo motor is completed in a state where the power supply to the servo motor is resumed by the resumption unit, and it is detected by the position detection unit that the spindle is located within the tool change area. In a numerical control device, the operation of the tool magazine by driving the servo motor is completed, and the spindle moves from the tool change area to the machining area. In the numerical control device, the power supply to the servo motor is interrupted on the condition that it is detected that the spindle is located within the tool change area. Therefore, the numerical control device can interrupt the power supply to the servo motor at a position within the tool change area according to the specifications, and can reduce the power consumption of the servo motor as compared with the case where the power supply to the servo motor is performed between when the operation of the tool magazine is completed and when the spindle moves to the machining area.

[0011] In a numerical control device, the tool magazine is operable when the spindle is located at a specific spindle position within the tool change area. The resumption unit resumes the power supply to the servo motor on the condition that the position detection unit detects that the tool magazine is operable and the spindle is located at the specific spindle position within the tool change area. The interruption unit may interrupt the power supply to the servo motor when the operation of the tool magazine by the servo motor is completed in a state where the power supply to the servo motor has been resumed by the resumption unit and the position detection unit detects that the spindle has left the specific spindle position. In a numerical control device, power is supplied to the servo motor while the servo motor is driven, and the power supply to the servo motor is interrupted when the driving of the servo motor is completed. Therefore, the numerical control device can further reduce the power consumption of the servo motor.

[0012] The numerical control device may include a switching unit that switches between enabling and disabling the interruption of the power supply to the servo motor by the interruption unit. Thereby, the numerical control device can realize specifications according to the machine tool.

[0013] A control method according to a second aspect of the present invention is a control method for controlling the operation of a machine tool including a spindle movable between a machining area where a tool can be mounted and machining of a workpiece using the tool is performed, and a tool change area where the tool is changed, and a tool magazine capable of loading the tool and conveying the tool mounted on the spindle to a tool change position by driving a servo motor. The control method includes an interruption step of interrupting the power supply to the servo motor in a standby state where the tool magazine is not operated, a position detection step of detecting the position of the spindle, and a resumption step of resuming the power supply to the servo motor interrupted by the interruption step on the condition that the position detection step detects that the spindle is located within the tool change area.

[0014] The program according to the third aspect of the present invention is a spindle that can mount a tool and is movable to a machining area where machining of a workpiece is performed using the tool and a tool changing area where the tool is changed, and a tool magazine that can load the tool and conveys the tool mounted on the spindle to a tool changing position by driving a servo motor. In a standby state where the tool magazine is not operated, an interruption process for interrupting power supply to the servo motor, a position detection process for detecting the position of the spindle, and when it is detected by the position detection process that the spindle is located within the tool changing area, a restart process for restarting the power supply to the servo motor interrupted by the interruption process are executed.

[0015] The control method according to the second aspect and the program according to the third aspect have the same effects as the numerical control device according to the first aspect.

Brief Description of Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The drawings referred to are used to explain the technical features that the present invention can adopt. That is, the configurations and the like shown in the drawings are not intended to be limited thereto, but are merely illustrative examples. In the following description, the left and right, front and rear, and up and down indicated by arrows in the drawings are used. The left and right direction, front and rear direction, and up and down direction of the machine tool 1 are the X-axis direction, Y-axis direction, and Z-axis direction of the machine tool 1, respectively.

[0018] The machine tool 1 shown in Fig. 1 rotates the tool 3 mounted on the spindle 9 and performs a cutting process on a workpiece (not shown) held on the upper surface of the table 13. The numerical control device 30 (see Fig. 2) controls the operation of the machine tool 1 based on an NC program described later.

[0019] <Structure of the machine tool 1> Referring to Fig. 1, the structure of the machine tool 1 will be described. The machine tool 1 includes a base 2, a column 5, a table device 10, a Z-axis movement mechanism 8, a spindle head 7, a spindle 9, a tool changer 20, a control box 6, and an operation panel 15 (see Fig. 3). The base 2 is a substantially rectangular parallelepiped-shaped metal base that is long in the front and rear directions. The column 5 is fixed to the rear part of the upper surface of the base 2. The column 5 is a vertical column that extends in the up and down direction. The control box 6 is fixed to the back surface of the column 5. The control box 6 houses the numerical control device 30.

[0020] The operation panel 15 is provided on the outer wall of a cover (not shown) that covers the machine tool 1, for example, and has an operation unit 16 and a display unit 17 (see Fig. 3). The operation unit 16 receives inputs of various information, various instructions, etc., and outputs them to the numerical control device 30. The display unit 17 displays various screens based on commands from the numerical control device 30.

[0021] The table device 10 has a Y-axis moving mechanism (not shown), a Y-axis table 12, a table 13, and an X-axis moving mechanism (not shown). The Y-axis moving mechanism is provided on the upper surface of the base 2 and in front of the column 5, and has a Y-axis motor 52 (see FIG. 3). The Y-axis moving mechanism moves the Y-axis table 12 in the Y-axis direction in response to the drive of the Y-axis motor 52. The X-axis moving mechanism is provided on the upper part of the Y-axis table 12 and has an X-axis motor 51 (see FIG. 3). The X-axis moving mechanism moves the table 13 in the X-axis direction in response to the drive of the X-axis motor 51. Therefore, the table 13 can move above the base 2 in the X-axis direction and the Y-axis direction by the X-axis moving mechanism and the Y-axis moving mechanism.

[0022] The table device 10 has a Y-axis moving mechanism (not shown), a Y-axis table 12, an X-axis moving mechanism (not shown), and a table 13. The Y-axis moving mechanism is provided at the front part of the upper surface of the base 2 and includes a Y-axis rail, a Y-axis ball screw, and a Y-axis motor 52 (see FIG. 3). The Y-axis rail and the Y-axis ball screw extend in the Y-axis direction. The Y-axis rail guides the Y-axis table 12 in the Y-axis direction. The Y-axis table 12 is in the shape of a rectangular plate in plan view, and a Y-axis nut (not shown) is provided on the lower surface. The Y-axis nut is screwed onto the Y-axis ball screw. When the Y-axis motor 52 rotates the Y-axis ball screw, the Y-axis table 12 is guided by the Y-axis rail together with the Y-axis nut and moves in the Y-axis direction.

[0023] The X-axis moving mechanism is provided on the upper surface of the Y-axis table 12 and has an X-axis rail, an X-axis ball screw, and an X-axis motor 51 (see FIG. 3). The X-axis rail and the X-axis ball screw extend in the X-axis direction. The X-axis rail guides the table 13 in the X-axis direction. The table 13 is provided on the upper surface of the Y-axis table 12 and is in the shape of a rectangular plate in plan view. A workpiece to be machined (not shown) is held on the upper surface of the table 13. An X-axis nut (not shown) is provided on the lower surface of the table 13. The X-axis nut is screwed onto the X-axis ball screw. When the X-axis motor 51 rotates the X-axis ball screw, the table 13 is guided by the X-axis rail together with the X-axis nut and moves in the X-axis direction. Therefore, the table 13 can move above the base 2 in the X-axis direction and the Y-axis direction by the X-axis moving mechanism and the Y-axis moving mechanism.

[0024] <Structure of the Z-axis movement mechanism 8> As shown in Fig. 2, the Z-axis movement mechanism 8 is provided at the front part of the column 5. The Z-axis movement mechanism 8 has a Z-axis rail (not shown), a Z-axis ball screw 81, bearing parts 82, 83, a cam follower 89, and a Z-axis motor 53 (see Fig. 3). The Z-axis rail and the Z-axis ball screw 81 are provided at the front part of the column 5 and extend in the Z-axis direction. The bearing parts 82, 83 are inserted through the Z-axis ball screw 81 and rotatably support the Z-axis ball screw 81. The bearing part 82 is provided above the bearing part 83. The cam follower 89 is provided at the front end of the bearing part 82. The cam follower 89 slides on the cam surface of a plate cam 74 described later.

[0025] The Z-axis motor 53 is fixed above the bearing part 82. The Z-axis ball screw 81 is connected to the output shaft of the Z-axis motor 53 via a coupling (not shown). A Z-axis nut 84 is screwed between the bearing parts 82, 83 on the Z-axis ball screw 81. The Z-axis nut 84 is fixed to the spindle head 7 described later. When the Z-axis motor 53 rotates the Z-axis ball screw 81, the spindle head 7 moves in the Z-axis direction guided by the Z-axis rail together with the Z-axis nut 84.

[0026] <Internal structure of the spindle head 7> As shown in Fig. 2, the spindle head 7 is provided at the front part of the column 5 and is box-shaped. The spindle head 7 has a spindle motor 54, a support shaft 71, a crank lever 72, and a spring 73. The spindle motor 54 is fixed to the front part of the upper surface of the spindle head 7.

[0027] The support shaft 71 extends in the left-right direction inside the rear part of the spindle head 7. The crank lever 72 is substantially L-shaped in a left side view, and the bent part engages with the support shaft 71. The crank lever 72 is swingable about the support shaft 71. A plate cam 74 is provided at the rear end of the crank lever 72. A cam surface that can be in contact with and separated from the cam follower 49 is formed on the back surface of the plate cam 47. The spring 73 is a compression coil spring extending in the front-rear direction. One end of the spring 73 is fixed to the back wall of the spindle head 7. The other end of the spring 73 is fixed to the rear end of the crank lever 72 below the plate cam 74. The spring 73 constantly biases the crank lever 72 clockwise in a right side view.

[0028] <Structure of the spindle 9> As shown in Fig. 2, the spindle 9 is provided inside the front part of the spindle head 7 and extends in the vertical direction. The spindle 9 is rotatably supported by the spindle head 7. The spindle 9 is connected to the output shaft of the spindle motor 54. The spindle 9 has a shaft hole 91, a mounting hole 92, a clamping part 93, and a drawbar 94.

[0029] The shaft hole 91 is provided at the upper end of the spindle 9. The mounting hole 92 is provided at the lower end of the spindle 9 and communicates with the shaft hole 91. The clamping part 93 is provided at the lower end inside the shaft hole 91. The clamping part 93 can clamp the tool 3. The drawbar 94 is provided inside the shaft hole 91 at the upper end of the clamping part 93. At the upper end of the drawbar 94, a pin 95 protruding outside the spindle 9 is provided through a through hole (not shown) that penetrates the spindle 9 in the front-rear direction. The pin 95 is located below the front end of the crank lever 72. When the crank lever 72 swings, the front end of the crank lever 72 comes into contact with and separates from the pin 95.

[0030] <Structure of the tool changer 20> As shown in Fig. 2, the tool changer 20 includes a tool magazine 21 and a magazine motor 55. The tool magazine 21 is of the turret type. The tool magazine 21 has a support base 24, a support shaft 25, a magazine body 22, a plurality of grip arms 23, and a speed reducer 26.

[0031] The support base 24 is fixed to a frame (not shown). The frame is fixed to the column 5 and provided near the spindle head 7. The support base 24 is located in front of the spindle head 7 and rotatably supports the support shaft 25. The support shaft 25 extends obliquely downward in front of the machine tool 1. The magazine body 22 is provided at the front part of the support base 24 and supported by the support shaft 25. The magazine body 22 is disk-shaped and is provided facing the front of the machine tool 1.

[0032] Each grip arm 23 is provided at predetermined intervals on the outer periphery of the magazine body 22. Each grip arm 23 is provided so as to be swingable in the front-rear direction of the magazine body 22. The tip of the grip arm 23 detachably holds the tool 3. That is, the tool magazine 21 loads the tool 3 by a plurality of grip arms 23. The speed reducer 26 is provided on the upper part of the support base 24. The speed reducer 26 has a plurality of gears and cams (not shown). The magazine motor 55 is provided on the upper part of the speed reducer 26. The rotating shaft of the magazine motor 55 is connected to the speed reducer 26. By driving the magazine motor 55, the magazine body 22 rotates via the speed reducer 26.

[0033] <Electrical Configuration of Numerical Control Device 30 and Machine Tool 1> Referring to FIG. 3, the electrical configuration of the numerical control device 30 and the machine tool 1 will be described. The numerical control device 30 includes a CPU 31, a ROM 32, a RAM 33, a storage device 34, an input / output unit 35, and drive circuits 41 to 45. The CPU 31 comprehensively controls the numerical control device 30.

[0034] The ROM 32 stores various setting information. The RAM 33 temporarily stores various information. The storage device 34 is non-volatile and stores a plurality of NC programs described later, control programs for executing main processing (see FIG. 5), and the like. The NC program is a machining program composed of a plurality of lines. Each line of the NC program includes a control command for performing various operations including axis movement and tool change of the machine tool 1. The numerical control device 30 executes the control commands constituting the NC program in line units to control the operation of the machine tool 1.

[0035] The input / output unit 35 performs input / output of various signals between the CPU 31, the RAM 33, the storage device 34, the input / output unit 35, the drive circuits 41 to 45, the operation unit 16, and the display unit 17.

[0036] The drive circuit 41 is connected to the input / output unit 35, the X-axis motor 51, and the encoder 51A. The drive circuit 42 is connected to the input / output unit 35, the Y-axis motor 52, and the encoder 52A. The drive circuit 43 is connected to the input / output unit 35, the Z-axis motor 53, and the encoder 53A. The drive circuit 44 is connected to the input / output unit 35, the spindle motor 54, and the encoder 54A. The drive circuit 45 is connected to the input / output unit 35, the magazine motor 55, and the encoder 55A.

[0037] Based on the commands input from the CPU 31, the drive circuits 41, 42, 43, 44, and 45 output drive currents to the X-axis motor 51, the Y-axis motor 52, the Z-axis motor 53, the spindle motor 54, and the magazine motor 55. The X-axis motor 51, the Y-axis motor 52, the Z-axis motor 53, the spindle motor 54, and the magazine motor 55 are all servo motors and rotate according to the input drive currents.

[0038] The encoders 51A, 52A, 53A, 54A, and 55A are all absolute encoders and detect the rotational positions of the X-axis motor 51, the Y-axis motor 52, the Z-axis motor 53, the spindle motor 54, and the magazine motor 55.

[0039] The encoders 51A, 52A, 53A, 54A, and 55A output feedback signals indicating the detected rotational positions to the drive circuits 41, 42, 43, 44, and 45. The drive circuits 41, 42, 43, 44, and 45 perform feedback control on the X-axis motor 51, the Y-axis motor 52, the Z-axis motor 53, the spindle motor 54, and the magazine motor 55 based on the feedback signals. The CPU 31 detects the position in the X-axis direction of the table 13, the position in the Y-axis direction of the table 13, the position in the Z-axis direction of the spindle 9, and the rotational position of the tool magazine 21 based on the feedback signals output by the encoders 51A, 52A, 53A, and 55A, respectively.

[0040] The magazine motor 55 has a holding brake 55B. The holding brake 55B is a non-excitation operation type brake and operates without consuming power. The holding brake 55B holds the rotating shaft of the magazine motor 55 when power supply to the magazine motor 55 is not performed, and holds the state (rotational position of the tool magazine 21) of the tool magazine 21. The holding brake 55B releases the holding of the rotating shaft of the magazine motor 55 when power supply to the magazine motor 55 is performed, and enables the tool magazine 21 to rotate by the magazine motor 55. When power supply to the magazine motor 55 is performed, the magazine motor 55 is driven based on a command for determining the rotational position of the tool magazine 21, and the state of the tool magazine 21 is held.

[0041] <Tool change of tool 3 by tool changer 20> Referring to FIGS. 2 and 7, the tool change of tool 3 by tool changer 20 will be described. When performing the tool change of tool 3 by tool changer 20, the numerical control device 30 outputs a tool change command. When the numerical control device 30 outputs a tool change command, the spindle 9 rises from the machining area shown in FIG. 7 by driving the Z-axis motor 53. The machining area is an area for machining the workpiece, and is an area on the table 13 side (lower side) with respect to the machine origin of the Z-axis. Hereinafter, the machine origin of the Z-axis is referred to as the Z-axis origin.

[0042] The spindle 9 rises and reaches the tool change area shown in FIG. 7. The tool change area is an area for changing the tool 3 mounted on the spindle 9, and is an area on the upper side with respect to the machine origin of the Z-axis. When the spindle 9 reaches the tool change area, the cam follower 89 slides on the cam surface of the plate cam 74. The crank lever 72 rotates counterclockwise in a right side view about the support shaft 71, and the front end portion of the crank lever 72 engages with the pin 95 from above and presses the draw bar 94 downward. The draw bar 94 biases the clamping portion 93 downward, and the clamping portion 93 releases the clamping of the tool 3. At the same time, the grip arm 23 located at the tool change position grips the tool 3. The tool change position is the lowermost position of the magazine body 22 and a position facing close to the spindle 9.

[0043] The main shaft 9 rises from the Z-axis origin to the ATC origin shown in FIG. 7. The ATC origin is the position of the main shaft 9 where the tool magazine 21 can rotate, and is also the position of the main shaft 9 within the tool change area. The tool 3 detaches from the mounting hole 92 of the main shaft 9 while being gripped by the grip arm 23. The tool 3 detached from the main shaft 9 is referred to as the first tool.

[0044] When the main shaft 9 reaches the ATC origin, the magazine motor 55 is driven based on the control command of the numerical control device 30, and the magazine body 22 of the tool magazine 21 rotates. The tool changer 20 determines the tool 3 (hereinafter referred to as the second tool) specified by the tool change command to the tool change position. At this time, the magazine body 22 rotates from the state where the first tool is at the tool change position to the state where the second tool is at the tool change position. The second tool determined to be at the tool change position is located below the main shaft 9 that has moved to the ATC origin.

[0045] The main shaft 9 descends from the ATC origin by the rotation of the Z-axis motor 53. The second tool enters the mounting hole 92 of the main shaft 9. The cam follower 89 slides on the cam surface of the plate cam 74. The crank lever 72 rotates clockwise in a right side view about the support shaft 71, and the front end of the crank lever 72 moves away from the pin 95 and releases the downward pressing of the draw bar 94. The draw bar 94 releases the downward biasing of the clamping portion 93, and the clamping portion 93 clamps the tool 3. The second tool detaches from the grip arm 23 at the tool change position. The tool 3 is mounted on the mounting hole 92 of the main shaft 9. The main shaft 9 reaches the Z-axis origin, which is the upper end of the machining area, from the tool change area, and the replacement of the tool 3 is completed.

[0046] <Control Mode of Power Supply to Magazine Motor 55> Referring to FIG. 4, the control mode of power supply to the magazine motor 55 will be described. The numerical control device 30 switches between a first mode and a second mode as the control mode of power supply to the magazine motor 55. The first mode is a mode in which power supply to the magazine motor 55 is performed when the tool magazine 21 is rotated as an operation of the tool magazine 21, and power supply to the magazine motor 55 is not performed in a standby state where the tool magazine 21 is not rotated. The second mode is a mode in which power supply to the magazine motor 55 is performed regardless of the state of the tool magazine 21. Here, "power supply to the magazine motor 55" means power supply to the power terminal for receiving the drive current input to rotate the magazine motor 55. That is, it is only necessary to control the power supply to the power terminal of the magazine motor 55, and the power supply to the signal terminal for transmitting and receiving signals for controlling the magazine motor 55 may or may not be performed.

[0047] More specifically, in the first mode, when the tool 3 mounted on the spindle 9 is not replaced, power supply to the magazine motor 55 is not performed, and the state of the tool magazine 21 is held by the holding brake 55B. When the tool 3 mounted on the spindle 9 is not replaced, for example, when machining of the workpiece is performed using the tool 3.

[0048] In the first mode, power supply to the magazine motor 55 is performed on the condition that it is detected that the spindle 9 is located within the tool change area. In the present embodiment, when it is detected that the spindle 9 is located at the ATC origin within the tool change area, power supply to the magazine motor 55 is performed. When the numerical control device 30 outputs a tool change command at time T1 to replace the tool 3, the spindle 9 located in the machining area rises toward the ATC origin within the tool change area.

[0049] When the spindle 9 reaches the ATC origin at time T3 (>T1), the holding brake 55B is released to rotate the tool magazine 21, and the power supply to the magazine motor 55 is restarted. The determination as to whether the spindle 9 has reached the ATC origin is made based on the position of the spindle 9 in the Z-axis direction detected by the encoder 53A.

[0050] When the tool magazine 21 rotates due to the drive of the magazine motor 55, when the tool 3 mounted on the spindle 9 is indexed to the tool change position at time T4 (> T3), the spindle 9 starts to descend from the ATC origin. The determination of whether the tool 3 mounted on the spindle 9 has been indexed to the tool change position is made based on the rotational position of the tool magazine 21 detected by the encoder 55A.

[0051] In the first mode, the power supply to the magazine motor 55 is interrupted on the condition that the rotation of the tool magazine 21 is completed. In the present embodiment, the power supply to the magazine motor 55 is interrupted on the condition that it is detected that the spindle 9 is located at a predetermined position within the tool change area. Here, "on the condition that it is detected that the spindle 9 is located within the tool change area" means that it is detected that the spindle 9 is separated from a predetermined position within the tool change area. In the present embodiment, the predetermined position within the tool change area on the spindle 9 is the ATC origin. When the spindle 9 that has started to descend is separated from the ATC origin, the power supply to the magazine motor 55 is interrupted and the holding brake 55B is activated. The determination of whether the spindle 9 is separated from the ATC origin is made based on the position of the spindle 9 in the Z-axis direction detected by the encoder 53A.

[0052] Since no power is consumed when the holding brake 55B is activated, the power is consumed by the magazine motor 55 in the first mode only between time T3 and time T4. Then, until the tool magazine 21 rotates based on the next tool change command, the power supply to the magazine motor 55 is not performed, and the state of the tool magazine 21 is held by the holding brake 55B.

[0053] In the second mode of one side, since power is supplied to the magazine motor 55 regardless of the state of the tool magazine 21, the state of the tool magazine 21 is maintained by the magazine motor 55 driven based on the feedback signal from the encoder 55A. For example, when the tool magazine 21 rotates from the designated rotational position due to the unbalanced load generated in the tool magazine 21 with the tool 3 loaded, the drive circuit 45 drives the magazine motor 55 based on the feedback signal to rotate the tool magazine 21 in the reverse direction so that the tool magazine 21 reaches the designated rotational position. Thus, in the second mode, since the magazine motor 55 is driven to maintain the state of the tool magazine 21, power is constantly consumed by the magazine motor 55.

[0054] <Main process> Referring to FIGS. 5 and 6, the main process executed by the CPU 31 will be described. When the power of the machine tool 1 and the numerical control device 30 is turned on, the main process starts by calling the control program of the main process from the storage device 34 and executing the called control program.

[0055] As shown in FIG. 5, when the main process starts, the CPU 31 determines whether power is being supplied to the X-axis motor 51, Y-axis motor 52, Z-axis motor 53, spindle motor 54, and magazine motor 55 (S1). For example, when the machine tool 1 stopped abnormally due to an error during the previous use, power may not be supplied to the X-axis motor 51, Y-axis motor 52, Z-axis motor 53, spindle motor 54, and magazine motor 55 when the power of the machine tool 1 is turned on. If the CPU 31 determines that power is not being supplied to the X-axis motor 51, Y-axis motor 52, Z-axis motor 53, spindle motor 54, and magazine motor 55 (S1: NO), the process returns to S1.

[0056] When the CPU 31 determines that power is being supplied to the X-axis motor 51, Y-axis motor 52, Z-axis motor 53, spindle motor 54, and magazine motor 55 (S1: YES), it determines whether a mode change instruction has been received (S2). The mode change instruction is an instruction to switch the control mode from the first mode to the second mode or from the second mode to the first mode. The operator inputs the mode change instruction using the operation unit 16 of the operation panel 15.

[0057] When the CPU 31 determines that a mode change instruction has been received (S2: YES), it determines whether the control mode is the first mode (S3). When the CPU 31 determines that the control mode is the first mode (S3: YES), assuming that the control mode is switched from the first mode to the second mode, it resumes power supply to the magazine motor 55 (S4) and releases the operation of the holding brake 55B. The CPU 31 sets the value of the mode flag to 1 (S5) and returns the process to S2. The value of the mode flag indicates whether the control mode is the first mode or the second mode. When the value of the mode flag is 0, it indicates that the control mode is the first mode. When the value of the mode flag is 1, it indicates that the control mode is the second mode.

[0058] When the CPU 31 determines that the control mode is not the first mode (S3: NO), assuming that the control mode is switched from the second mode to the first mode, it interrupts the power supply to the magazine motor 55 (S6) and operates the holding brake 55B. The holding brake 55B holds the state of the tool magazine 21. The CPU 31 sets the value of the mode flag to 0 (S5) and returns the process to S2.

[0059] When the CPU 31 determines that a mode change instruction has not been received (S2: NO), it determines whether a machining start instruction has been received (S11). The machining start instruction is an instruction to machine the workpiece. The operator inputs the machining start instruction using the operation unit 16 of the operation panel 15. When the CPU 31 determines that a machining start instruction has not been received (S11: NO), it returns the process to S2.

[0060] When the CPU 31 determines that it has received an instruction to start processing (S11: YES), it reads one NC program specified from among a plurality of NC programs stored in the storage device 34 (S12). When machining the workpiece, when the control mode is the first mode, the holding brake 55B holds the state of the tool magazine 21, and when the control mode is the second mode, the magazine motor 55 holds the state of the tool magazine 21. The spindle 9 is positioned in the machining area.

[0061] The CPU 31 interprets a control command for one line from the read NC program (S13). The CPU 31 determines whether the interpreted control command is an end command (S14). The end command is a control command that ends the execution of the NC program. When the CPU 31 determines that the interpreted control command is not an end command (S14: NO), it determines whether the interpreted control command is a tool change command (S15). When the CPU 31 determines that the interpreted control command is a tool change command (S15: YES), the process proceeds to S21 (see FIG. 6).

[0062] As shown in FIG. 6, the CPU 31 drives the Z-axis motor 53 to start raising the spindle 9 in order to replace the tool 3 mounted on the spindle 9 (S21). The spindle 9 rises from the machining area toward the ATC origin within the tool change area. The tool 3 held by the spindle 9 is detached from the spindle 9 and gripped by the gripper arm 23 of the tool magazine 21.

[0063] The CPU 31 determines whether the spindle 9 is positioned at the ATC origin as a condition for detecting that the spindle 9 is positioned within the tool change area (S22). The CPU 31 makes the determination in S22 based on the rotational position of the Z-axis motor 53 specified by the encoder 53A. When the CPU 31 determines that the spindle 9 is not positioned at the ATC origin (S22: NO), the process returns to S22. When the CPU 31 determines that the spindle 9 is positioned at the ATC origin (S22: YES), it stops driving the Z-axis motor 53 and stops raising the spindle 9 (S23).

[0064] The CPU 31 determines whether the control mode is the first mode (S24). When the CPU 31 determines that the value of the mode flag is 0 and the control mode is the first mode (S24: YES), it resumes the power supply to the interrupted magazine motor 55 (S25). When the power supply to the magazine motor 55 is resumed, the operation of the holding brake 55B is released, so the tool magazine 21 becomes rotatable. The CPU 31 shifts the process to S31.

[0065] When the CPU 31 determines that the value of the mode flag is 1 and the control mode is not the first mode (S24: NO), it shifts the process to S31. In this case, the control mode is the second mode, the power supply to the magazine motor 55 is constantly performed, and the tool magazine 21 is rotatable.

[0066] The CPU 31 drives the magazine motor 55 to rotate the magazine body 22 of the tool magazine 21 (S31). The CPU 31 rotates the tool magazine 21 so that the tool 3 mounted on the spindle 9 is indexed to the tool change position.

[0067] The CPU 31 determines whether the tool 3 mounted on the spindle 9 has been indexed to the tool change position as a condition for the completion of the rotation of the tool magazine 21 by the magazine motor 55 (S32). The CPU 31 makes the determination in S32 based on the rotation position of the magazine motor 55 specified by the encoder 55A. When the CPU 31 determines that the tool 3 mounted on the spindle 9 has not been indexed to the tool change position (S32: NO), it returns the process to S32. When the CPU 31 determines that the tool 3 mounted on the spindle 9 has been indexed to the tool change position (S32: YES), it stops the drive of the magazine motor 55 and stops the rotation of the tool magazine 21 (S33).

[0068] The CPU 31 drives the Z-axis motor 53 to start the descent of the spindle 9 in order to mount the tool 3 indexed to the tool change position on the spindle 9 (S34). The spindle 9 descends from the ATC origin toward the machining area.

[0069] When the CPU31 detects that the spindle 9 is located within the tool change area, it determines whether the spindle 9 is separated from the ATC origin (S35). The CPU31 makes the determination in S35 based on the rotational position of the Z-axis motor 53 specified by the encoder 53A. If the CPU31 determines that the spindle 9 is not separated from the ATC origin (S35: NO), the process returns to S35. If the CPU31 determines that the spindle 9 is separated from the ATC origin (S35: YES), it determines whether the control mode is the first mode (S36).

[0070] If the value of the mode flag is 0 and the CPU31 determines that the control mode is the first mode (S36: YES), it interrupts the power supply to the magazine motor 55 that had been restarted (S37). When the power supply to the magazine motor 55 is interrupted, the holding brake 55B operates, so the state of the tool magazine 21 is held by the holding brake 55B. The CPU31 transfers the process to S38.

[0071] If the value of the mode flag is 1 and the CPU31 determines that the control mode is not the first mode (S36: NO), it transfers the process to S38. In this case, the control mode is the second mode, the power supply to the magazine motor 55 is constantly supplied, and the state of the tool magazine 21 is held by the magazine motor 55.

[0072] Based on the rotational position of the Z-axis motor 53 specified by the encoder 53A, the CPU31 determines whether the spindle 9 that started descending in S34 has reached the Z-axis origin, which is the upper end of the machining area (S38). If the CPU31 determines that the spindle 9 has not reached the Z-axis origin (S38: NO), the process returns to S38. If the CPU31 determines that the spindle 9 has reached the Z-axis origin (S38: YES), it stops driving the Z-axis motor 53 to stop the descent of the spindle 9 (S39), and returns the process to S13 (see Fig. 5).

[0073] As shown in FIG. 5, when the CPU 31 determines that the interpreted control command is not a tool change command (S15: NO), it executes various processes based on the control command (S16), and returns the process to S13. The various processes executed in S16 are, for example, the positioning process of the spindle 9 and the rotation process of the spindle 9.

[0074] When the CPU 31 determines that the interpreted control command is an end command (S14: YES), it ends the machining of the workpiece based on the NC program (S17), and returns the process to S2.

[0075] <Operations and Effects of this Embodiment> As described above, the numerical control device 30 detects the position of the spindle 9 in the Z-axis direction by the encoder 55A. The numerical control device 30 interrupts the power supply to the magazine motor 55 in the standby state where the tool magazine 21 is not operated (S6, S37). When the numerical control device 30 exchanges the tool 3 mounted on the spindle 9 based on a tool change command, the CPU 31 detects the position of the spindle 9 in the Z-axis direction by the encoder 55A (S22), and resumes the power supply to the magazine motor 55 on the condition that the spindle 9 is detected to be located within the tool change area (S25). In the numerical control device 30, when a tool change command is output, the spindle 9 moves from the machining area to the tool change area, and the tool magazine 21 rotates by driving the magazine motor 55. In the numerical control device 30, the power supply to the magazine motor 55 is resumed on the condition that the spindle 9 is detected to be located within the tool change area. Therefore, compared with the case where the power supply to the magazine motor 55 is resumed when the tool change command is output, the numerical control device 30 can reduce the power consumed by the magazine motor 55 until the spindle 9 moves from the machining area to the tool change area.

[0076] The numerical control device 30 resumes power supply to the magazine motor 55 (S25) on the condition that it is detected that the spindle 9 is positioned at the ATC origin (S22: YES). In the numerical control device 30, the tool magazine 21 is rotatable when the spindle 9 is positioned at the ATC origin within the tool change area. When exchanging the tool 3 based on a tool change command, when the spindle 9 reaches the ATC origin, the numerical control device 30 drives the magazine motor 55 to rotate the tool magazine 21. In the numerical control device 30, since power supply to the magazine motor 55 is resumed immediately before starting the rotation of the tool magazine 21, the power consumption of the magazine motor 55 is further reduced.

[0077] The numerical control device 30 interrupts power supply to the magazine motor 55 (S37) on the condition that the rotation of the tool magazine 21 by the magazine motor 55 is completed (S32: YES) and it is detected that the spindle 9 is positioned within the tool change area (S35). In the numerical control device 30, when the rotation of the tool magazine 21 by the magazine motor 55 is completed, the spindle 9 moves from the machining area to the tool change area. In the numerical control device 30, power supply to the magazine motor 55 is interrupted again on the condition that it is detected that the spindle 9 is positioned within the tool change area. Therefore, the numerical control device 30 can reduce the power consumed by the magazine motor 55 until the spindle 9 moves from the tool change area to the machining area.

[0078] When it is detected that the spindle 9 is positioned at the ATC origin within the tool change area (S22), the numerical control device 30 resumes the power supply to the magazine motor 55 (S31). Then, when the rotation of the tool magazine 21 by driving the magazine motor 55 whose power supply has been resumed is completed (S32) and it is detected that the spindle 9 is positioned at the ATC origin (S35), the numerical control device 30 interrupts the power supply to the magazine motor 55 (S37). In the numerical control device 30, the power supply to the magazine motor 55 is performed while the magazine motor 55 is being driven (from time T3 to time T4), and when the rotation of the tool magazine 21 by driving the magazine motor 55 is completed, the power supply to the magazine motor 55 is interrupted. Therefore, the numerical control device 30 can further reduce the power consumption of the magazine motor 55.

[0079] The numerical control device 30 switches between a first mode (S7) in which the power supply to the magazine motor 55 is interrupted and a second mode (S5) in which the power supply to the magazine motor 55 is constantly performed. Thereby, the numerical control device 30 can realize specifications adapted to the machine tool 1.

[0080] <Modification Example> The present invention can be variously modified from the above-described embodiment. The following various modification examples can be combined with each other as long as no contradiction occurs. The numerical control device 30 is not limited to being provided in the machine tool 1, and may be provided separately from the machine tool 1. For example, the numerical control device 30 may be a control device (PC, dedicated machine, etc.) electrically connected to the machine tool 1.

[0081] Instead of the CPU 31, for example, a microcomputer, an ASIC (Application Specific Integrated Circuits), an FPGA (Field Programmable Gate Array), etc. may be used for the control of the numerical control device 30. The main processing may be distributedly processed by a plurality of control devices.

[0082] Non-transitory storage media such as the ROM 32 and the storage device 34 may be any storage media that can retain information regardless of the period for which the information is stored. The non-transitory storage media may not include transitory storage media (e.g., transmitted signals). The control program for executing the main processing may be downloaded (i.e., transmitted as a transmission signal) from, for example, a server (not shown) connected to a network and stored in the storage device 34. In this case, the control program may be stored in a non-transitory storage media such as an HDD provided in the server.

[0083] The machine tool 1 only needs to be able to move the spindle 9 between the machining area and the tool change area, and the configuration of the machine tool 1 may be changed as appropriate. The machine tool 1 is not limited to an upright machine tool in which the spindle 9 extends vertically, and may be a horizontal machine tool in which the spindle 9 extends horizontally. The direction in which the spindle 9 moves is not limited to the Z-axis direction, and it may be movable in the X-axis direction or the Y-axis direction.

[0084] The tool magazine 21 only needs to convey the tool 3 mounted on the spindle 9 to the tool change position by driving a servo motor. In the above embodiment, the tool magazine 21 is a turret type, but the tool magazine 21 may be, for example, an arm type. In the above embodiment, as the operation of the tool magazine 21, the magazine body 22 rotates about the center of the support shaft 25 by driving the magazine motor 55, but the tool magazine 21 may perform operations other than rotation. For example, as the operation of the tool magazine 21, the magazine body 22 may be translated by driving the magazine motor 55. In the above embodiment, the drive circuits 41 to 45 are provided in the numerical control device 30, but the drive circuits 41 to 45 may be provided in the machine tool 1.

[0085] In the above embodiment, the numerical control device 30 detected the position of the spindle 9 in the Z-axis direction based on the rotational position of the Z-axis motor 53 specified by the encoder 53A. On the other hand, the numerical control device 30 may estimate the speed of the spindle 9 based on a command input to the drive circuit 43 and detect the position of the spindle 9 in the Z-axis direction based on the estimated speed.

[0086] In the above embodiment, the numerical control device 30 resumed the power supply to the magazine motor 55 on the condition that it was detected that the numerical control device 30 was located at the ATC origin. In contrast, the numerical control device 30 may resume the power supply to the magazine motor 55 on the condition that it is detected that the main spindle 9 is located within the tool change area. That is, when the main spindle 9 is located at a position different from the ATC origin within the tool change area, the power supply to the magazine motor 55 may be resumed. A position within the tool change area different from the ATC origin is, for example, the Z-axis origin at the lower end of the tool change area.

[0087] In the above embodiment, when the rotation of the tool magazine 21 was completed and the main spindle 9 was separated from the ATC origin within the tool change area, the numerical control device 30 interrupted the power supply to the magazine motor 55. In contrast, the numerical control device 30 may not interrupt the power supply to the magazine motor 55 within the tool change area and may interrupt the power supply to the magazine motor 55 after the main spindle 9 has moved to the machining area.

[0088] When the numerical control device 30 determines that the rotation of the tool magazine 21 has been completed, the power supply to the magazine motor 55 may be interrupted. In this case, based on the rotational position of the magazine motor 55 identified by the encoder 55A, the numerical control device 30 may determine that the rotation of the tool magazine 21 has been completed when the tool 3 mounted on the main spindle 9 has been indexed to the tool change position. The numerical control device 30 may determine that the rotation of the tool magazine 21 has been completed when a predetermined time has elapsed since the magazine motor 55 was driven.

[0089] In the above-described embodiment, the numerical control device 30 interrupts the power supply to the magazine motor 55 on the condition that it is detected that the numerical control device 30 is located at the ATC origin. In contrast, the numerical control device 30 may interrupt the power supply to the magazine motor 55 on the condition that it is detected that the main spindle 9 is located within the tool change area. That is, when the rotation of the tool magazine 21 is completed and the main spindle 9 is located at a position different from the ATC origin within the tool change area, the numerical control device 30 may interrupt the power supply to the magazine motor 55. A position within the tool change area that is different from the ATC origin is, for example, the Z-axis origin at the lower end of the tool change area. The position of the main spindle 9 that serves as a criterion for determining to resume the power supply to the magazine motor 55 and the position of the main spindle 9 that serves as a criterion for determining to interrupt the power supply to the magazine motor 55 may be different from each other as long as they are within the tool change area.

[0090] The numerical control device 30 may be further switchable to a control mode different from the first mode and the second mode. The numerical control device 30 may control the power supply to the magazine motor 55 in the first mode without performing a control mode switch.

[0091] <Others> The CPU 31 that executes the processes of S6 and S37 is an example of the "interrupt unit" of the present invention. The processes of S6 and S37 are examples of the "interrupt step" and "interrupt process" of the present invention. The CPU 31 that executes the processes of S22 and S35 is an example of the "position detection unit" of the present invention. The processes of S22 and S35 are examples of the "position detection step" and "position detection process" of the present invention. The CPU 31 that executes the process of S25 is an example of the "resumption unit" of the present invention. The process of S25 is an example of the "resumption step" and "resumption process" of the present invention. The ATC origin is an example of the "specific spindle position" of the present invention. The CPU 31 that executes the processes of S4 and S6 is an example of the "switching unit" of the present invention.

Explanation of Reference Numerals

[0092] 1 Machine tool 8 Z-axis movement mechanism 9 Main spindle 20 Tool changer 21 Tool magazine 30 Numerical control device 31 CPU 53 Z-axis motor 53A Encoder 55 Magazine motor 55A Encoder 55B Holding brake

Claims

1. A numerical control device for controlling the operation of a machine tool, comprising a spindle that can be fitted with a tool and is movable to a machining area where machining of a workpiece is performed using the tool and a tool change area where the tool is changed, and a tool magazine that can load the tool and conveys the tool to be fitted to the spindle to a tool change position by driving a servo motor, an interruption unit that interrupts power supply to the servo motor in a standby state where the tool magazine is not operated, a position detection unit that detects the position of the spindle, and a restart unit that restarts power supply to the servo motor interrupted by the interruption unit on the condition that the position detection unit detects that the spindle is located within the tool change area. The numerical control device is characterized by comprising the above.

2. The tool magazine is operable when the spindle is located at a specific spindle position within the tool change area, The restart unit restarts power supply to the servo motor on the condition that the position detection unit detects that the spindle is located at the specific spindle position. The numerical control device according to Claim 1 is characterized by this.

3. The interruption unit interrupts power supply to the servo motor on the condition that the operation of the tool magazine by the servo motor is completed in a state where power supply to the servo motor has been restarted by the restart unit. The numerical control device according to Claim 1 is characterized by this.

4. The interruption unit interrupts power supply to the servo motor on the condition that the operation of the tool magazine by the servo motor is completed in a state where power supply to the servo motor has been restarted by the restart unit and the position detection unit detects that the spindle is located within the tool change area. The numerical control device according to Claim 3 is characterized by this.

5. The tool magazine is operable when the spindle is located at a specific spindle position within the tool change area, The restart unit restarts power supply to the servo motor on the condition that the position detection unit detects that the spindle is located at the specific spindle position. The numerical control device according to claim 4, wherein the interruption unit interrupts the power supply to the servo motor on the condition that the operation of the tool magazine by the servo motor is completed in a state where the power supply to the servo motor is resumed by the resumption unit, and the position detection unit detects that the spindle has moved away from the specific spindle position.

6. The numerical control device according to claim 1, further comprising a switching unit that switches between enabling and disabling the interruption of the power supply to the servo motor by the interruption unit.

7. A control method for controlling the operation of a machine tool, the machine tool including a spindle movable between a machining area where a tool can be mounted and machining of a workpiece using the tool is performed, and a tool change area where the tool is changed, and a tool magazine capable of loading the tool and transporting the tool to be mounted on the spindle to a tool change position by driving a servo motor, the method comprising: an interruption step of interrupting the power supply to the servo motor in a standby state where the tool magazine is not operated; a position detection step of detecting the position of the spindle; a resumption step of resuming the power supply to the servo motor interrupted by the interruption step on the condition that the position detection step detects that the spindle is positioned within the tool change area; The control method is characterized by executing the steps.

8. A program for causing a computer to control the operation of a machine tool, the machine tool including a spindle movable between a machining area where a tool can be mounted and machining of a workpiece using the tool is performed, and a tool change area where the tool is changed, and a tool magazine capable of loading the tool and transporting the tool to be mounted on the spindle to a tool change position by driving a servo motor, the program causing the computer to: perform an interruption process of interrupting the power supply to the servo motor in a standby state where the tool magazine is not operated; perform a position detection process of detecting the position of the spindle; perform a resumption process of resuming the power supply to the servo motor interrupted by the interruption process on the condition that the position detection process detects that the spindle is positioned within the tool change area; The program is characterized by causing the computer to execute the processes.

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