Numerical control device, control method, and program

Abstract

To provide a numerical control device, a control method, and a program that can operate a tool magazine and a spindle based on appropriate parameters even when the tool magazine is rotated with a time constant optimized according to the tool loading conditions during tool exchange.SOLUTION: A control unit sets a time constant for acceleration and deceleration in rotation operation of a tool magazine based on loading conditions of the tool magazine (S13). The control unit sets a parameter P2 based on a set time constant t1 (S17). The parameter P2 is for starting the rotation operation of the tool magazine after the tool magazine receives a tool from a spindle at a receiving position and before the spindle reaches a separating position, and for starting movement operation of the spindle from the separating position to an exchange position before the tool magazine rotates to a delivery position. In tool exchange, the rotation operation of the tool magazine and the movement operation of the spindle are executed based on the set time constant t1 and the set parameter P2 (S25).SELECTED DRAWING: Figure 6

Description

Technical Field

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

Background Art

[0002] The machine tool described in Patent Document 1 controls the operation of a tool magazine and a spindle to perform tool change. Tools are loaded in the tool magazine. A tool is mounted on the spindle. At the time of tool change, the machine tool performs a turning operation of the tool magazine after the spindle passes through the Z-axis origin and before reaching the ATC origin. The machine tool performs a moving operation of the spindle from the ATC origin to the Z-axis origin before the tool magazine reaches the target position. The turning operation and the moving operation are executed based on parameters for controlling these operations. In this way, the machine tool overlaps the turning operation of the tool magazine and the moving operation of the spindle to shorten the time for tool change.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the above-described machine tool is equipped with a function of setting the time constant when turning the tool magazine to an optimized time constant according to the tool loading condition on the tool magazine, the appropriate value of the above parameters changes with respect to the time constant after setting. If tool change is executed in a state where the parameter is not an appropriate value with respect to the time constant after setting, for example, there is a possibility that the spindle and the tool magazine interfere with each other.

[0005] An object of the present invention is to provide a numerical control device, a control method, and a program capable of operating a tool magazine and a spindle based on appropriate parameters even when the tool magazine is rotated with an optimized time constant according to the loading condition of the tool in tool change.

Means for Solving the Problems

[0006] The numerical control device according to claim 1 is capable of mounting a tool, and in tool change for exchanging the tool, a spindle movable between an exchange position for exchanging the tool by driving a drive motor and a separated position separated from the exchange position, and the tool can be loaded, and in the tool change, a tool magazine capable of turning around a turning axis by driving a magazine motor and turning between a receiving position for receiving the tool mounted on the spindle and a delivery position for delivering the tool to be mounted on the spindle to the spindle. A numerical control device for controlling a machine tool, comprising a control unit that controls the operations of the spindle and the tool magazine by outputting commands to the drive motor and the magazine motor, and the control unit is based on the loading condition of the tool magazine. A time constant setting process for setting a time constant for acceleration and deceleration in the turning operation of the tool magazine, and after the tool magazine receives the tool from the spindle at the receiving position, before the spindle reaches the separated position, the turning operation of the tool magazine is started, and before the tool magazine turns to the delivery position, a parameter for starting the moving operation of the spindle from the separated position to the exchange position, and a parameter setting process for setting based on the time constant set in the time constant setting process, and in the tool change, based on the time constant set in the time constant setting process and the parameter set by the parameter setting process, an operation control process for executing the turning operation of the tool magazine and the moving operation of the spindle is executed.

[0007] The above numerical control device can operate the tool magazine and the spindle based on appropriate parameters even when the tool magazine is rotated with an optimized time constant according to the loading condition of the tool in tool change.

[0008] In the numerical control device according to claim 2, the loading condition may be defined by at least one of the inertia and the unbalance load around the turning axis of the tool magazine. The numerical control device can set a time constant based on the inertia and the unbalance load.

[0009] The numerical control device according to claim 3 includes a storage unit that stores information indicating a correspondence relationship between the time constant and the parameter, and the parameter setting process may execute an arithmetic process of setting the parameter based on the time constant set in the time constant setting process and the information stored in the storage unit. The numerical control device can set a time constant based on the information indicating the correspondence relationship.

[0010] In the numerical control device according to claim 4, the time constant includes a reference time constant corresponding to the maximum inertia and the maximum unbalance load of the tool magazine, the parameter includes a reference parameter corresponding to the reference time constant, the information is a change rate of the parameter with respect to a change in the time constant, and the arithmetic process may calculate the parameter based on the reference time constant, the reference parameter, the time constant set by the time constant setting process, and the change rate. The numerical control device can obtain a parameter by calculation.

[0011] In the numerical control device according to claim 5, the parameter may include a first parameter indicating a position of the spindle at which the turning operation of the tool magazine can be started before the spindle reaches the separated position, and a second parameter indicating a turning position of the tool magazine at which the spindle can start the moving operation from the separated position toward the exchange position before the tool magazine turns to the delivery position. The numerical control device can control the operations of the tool magazine and the spindle based on the first parameter and the second parameter.

[0012] In the numerical control device according to claim 6, the time constant includes a reference time constant corresponding to the maximum inertia and the maximum unbalanced load of the tool magazine, and in the operation control process, when the time constant is set to the time constant shortened with respect to the reference time constant by the time constant setting process, the position of the spindle when starting the turning operation of the tool magazine from the receiving position to the delivery position is closer to the separation position than the position of the spindle when starting the turning operation of the tool magazine with the reference time constant, and the turning position of the tool magazine when starting the moving operation of the spindle from the separation position to the exchange position is farther from the delivery position than the turning position of the tool magazine when starting the moving operation of the spindle with the reference time constant, and the moving operation of the spindle may be started. The numerical control device can shorten the time required for tool change by shortening the time constant from the reference time constant.

[0013] In the numerical control device according to claim 7, the control unit may execute a reception process for receiving whether the execution of the time constant setting process is valid or invalid. In the above numerical control device, the user can change the time constant as necessary.

[0014] In the numerical control device according to claim 8, the parameter setting process may set different parameters depending on whether the total weight of the tools loaded in the tool magazine is equal to or greater than a predetermined value and whether the total weight of the tools loaded in the tool magazine is less than the predetermined value. In the above numerical control device, appropriate parameters can be set according to the total weight of the load in the tool magazine.

[0015] The control method according to claim 9 is applicable to a machine tool equipped with a tool and capable of replacing the tool. In the tool replacement process, the machine tool includes a spindle that can be driven by a drive motor to move between an exchange position for replacing the tool and a separated position separated from the exchange position, and a tool magazine that can load the tool and can rotate around a rotation axis by driving a magazine motor in the tool replacement process to rotate between a receiving position for receiving the tool mounted on the spindle and a delivery position for delivering the tool to be mounted on the spindle to the spindle. The control method is for a numerical control device that controls the operations of the spindle and the tool magazine by outputting commands to the drive motor and the magazine motor. The control method includes: a time constant setting step of setting a time constant for acceleration and deceleration in the rotation operation of the tool magazine based on the loading condition of the tool magazine; a parameter setting step of setting parameters for starting the rotation operation of the tool magazine after the tool magazine receives the tool from the spindle at the receiving position and before the spindle reaches the separated position, and starting the movement operation of the spindle from the separated position to the exchange position before the tool magazine rotates to the delivery position, based on the time constant set in the time constant setting step; and an operation control step of executing the rotation operation of the tool magazine and the movement operation of the spindle based on the time constant set in the time constant setting step and the parameters set in the parameter setting step in the tool replacement. The above control method obtains the same effect as the numerical control device according to claim 1.

[0016] The program according to claim 10 is capable of mounting a tool. In the tool change for exchanging the tool, a spindle that can be moved between an exchange position for exchanging the tool by driving a drive motor and a separated position separated from the exchange position, and the tool can be loaded. In the tool change, a tool magazine that can be rotated about a pivot axis by driving a magazine motor, and can be rotated between a receiving position for receiving the tool mounted on the spindle and a delivery position for delivering the tool to be mounted on the spindle to the spindle. A numerical control device that controls the operation of the spindle and the tool magazine by outputting commands to the drive motor and the magazine motor, and a computer of the numerical control device, based on the loading conditions of the tool magazine, a time constant setting step for setting a time constant for acceleration and deceleration in the pivoting operation of the tool magazine, and after the tool magazine receives the tool from the spindle at the receiving position, before the spindle reaches the separated position, the pivoting operation of the tool magazine is started, and before the tool magazine pivots to the delivery position, a parameter setting step for setting a parameter for starting the moving operation of the spindle from the separated position to the exchange position based on the time constant set in the time constant setting step, and in the tool change, based on the time constant set in the time constant setting step and the parameter set in the parameter setting step, an operation control step for executing the pivoting operation of the tool magazine and the moving operation of the spindle is executed. The above program obtains the same effect as the numerical control device of claim 1.

[0017] A computer-readable storage medium storing the above program is also novel and useful.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0019] An embodiment of the present invention will be described. The following description uses the left - right, up - down, and front - back directions indicated by arrows in the figures. The left - right, up - down, and front - back directions of the machine tool 1 are the X - axis direction, Y - axis direction, and Z - axis direction of the machine tool 1, respectively. The machine tool 1 shown in Fig. 1 is a vertical machining center in which the spindle 9 extends in the up - down direction (Z - axis direction). The "ATC" described in this embodiment is an abbreviation for "Automatic Tool Changer". Also, the "NC" described in this embodiment is an abbreviation for "Numerical Control".

[0020] Referring to Figs. 1 and 2, the structure of the machine tool 1 will be described. The machine tool 1 includes a base 2, a column 5, a control box 6, a table 13, a spindle head 7, a spindle 9, and a tool changer 20. The base 2 is a substantially rectangular parallelepiped - shaped metal base. The column 5 is erected at the rear of the upper part of the base 2. The control box 6 is provided on the back side of the column 5. The control box 6 houses the numerical control device 40 (see Fig. 4) described later. The table 13 is movable in two axial directions, the X - axis direction and the Y - axis direction. The spindle head 7 moves up and down in the Z - axis direction on the front surface of the column 5 by the driving force of a driving motor 63 (see Fig. 4).

[0021] As shown in Fig. 2, the main shaft 9 is rotatably supported inside the main shaft head 7. The main shaft motor 65 is fixed to the upper part of the main shaft head 7. The main shaft 9 is connected to a drive shaft 65A extending downward from the main shaft motor 65. The main shaft 9 rotates by the drive of the main shaft motor 65. The main shaft 9 includes a mounting hole 92, a shaft hole 91, a clamping portion 93, and a drawbar 94. The mounting hole 92 is provided at the lower end of the main shaft 9 and communicates with the shaft hole 91 extending coaxially with the main shaft 9. The clamping portion 93 is provided above the mounting hole 92. The drawbar 94 is provided inside the shaft hole 91.

[0022] The tool 3 includes a holder 17 and a cutting tool 4. The holder 17 holds the cutting tool 4 at one end side and includes a mounting portion 17A and a pull stud 17B at the other end side. The mounting portion 17A is mounted in the mounting hole 92 of the main shaft 9. The pull stud 17B protrudes in the axial direction of the cutting tool 4 from the top of the mounting portion 17A. When the mounting portion 17A is mounted in the mounting hole 92, the clamping portion 93 clamps the pull stud 17B. When the drawbar 94 presses the clamping portion 93 downward, the clamping portion 93 releases the clamping of the pull stud 17B.

[0023] The main shaft head 7 includes a crank lever 30 and a tension coil spring (not shown) inside. The crank lever 30 is substantially reverse L-shaped in a right side view and is swingable about a support shaft 31. The support shaft 31 extends in the left-right direction and is fixed inside the main shaft head 7. The front end portion of the crank lever 30 engages with a pin 95 provided on the drawbar 94 from above. A plate cam 32 is provided at the rear end portion of the crank lever 30. A cam follower 34 is supported forward on the upper front surface of the column 5. The cam follower 34 slides on the cam surface of the plate cam 32 that moves up and down. The tension coil spring constantly biases the crank lever 30 clockwise in a right side view. Therefore, the crank lever 30 constantly releases the downward pressing of the pin 95.

[0024] Referring to FIG. 2, the structure of the tool changer 20 will be described. The tool changer 20 includes a tool magazine 21, a support base 24, a speed reducer 25, and a magazine motor 64. The tool magazine 21 is of the turret type. The tool magazine 21 includes a magazine body 22, a swivel shaft 23, and a plurality of grip arms 8. The magazine body 22 is disk-shaped. The swivel shaft 23 is inclined obliquely downward with respect to the front of the machine tool 1. The axis of the swivel shaft 23 passes through the center of the magazine body 22 described later. The swivel shaft 23 is provided at the center of rotation of the magazine body 22. The front of the magazine body 22 faces the front side of the machine tool 1. The grip arms 8 are provided at predetermined intervals in the circumferential direction on the outer peripheral portion of the magazine body 22. In the present embodiment, 28 grip arms 8 are provided on the magazine body 22. Therefore, the tool magazine 21 can accommodate 28 tools 3. The grip arm 8 is provided so as to be swingable in the front-rear direction about a fulcrum base 26 fixed to the outer peripheral portion of the magazine body 22. The grip arm 8 is provided with a gripping portion 81 at its tip. The gripping portion 81 detachably grips the holder 17. The spindle position of the tool magazine 21 is the position at the lowermost part of the magazine body 22 and is a position close to and facing the spindle 9. The grip arm 8 at the spindle position faces the spindle 9 and becomes the target position for tool change.

[0025] The support base 24 is fixed to a frame (not shown). The frame is fixed to the column 5 and provided in the vicinity of the spindle head 7. The support base 24 supports the swivel shaft 23. The speed reducer 25 is fixed to the upper part of the support base 24. The speed reducer 25 has a plurality of gears and cams (not shown). The magazine motor 64 is fixed to the upper part of the speed reducer 25. The drive shaft of the magazine motor 64 is connected to the speed reducer 25. The speed reducer 25 reduces the driving force of the magazine motor 64 and transmits it to the swivel shaft 23. Therefore, the tool magazine 21 rotates by the driving force of the magazine motor 64.

[0026] Referring to FIG. 3, the Z-axis origin A1, ATC origin A2, receiving position B1, and delivery position B2 during tool change will be described. The spindle 9 moves up and down in the Z-axis direction together with the spindle head 7 by the drive of the drive motor 63. Specifically, the spindle 9 moves up and down between the Z-axis origin A1 and the ATC origin A2 during tool change. The Z-axis origin A1 is the position where the tool 3 is exchanged with the tool magazine 21. The ATC origin A2 is a position separated upward from the Z-axis origin A1.

[0027] Also, the magazine body 22 rotates around the rotation shaft 23 by the drive of the magazine motor 64 during tool change. This rotation operation is also referred to as the "rotation operation of the tool magazine 21". The rotation position of the magazine body 22 when the grip arm 8 that does not hold the tool 3 is at the spindle position is referred to as the "receiving position B1 of the tool magazine 21". The receiving position B1 is the position where the grip arm 8 receives the tool 3 (hereinafter also referred to as the "current tool 3") mounted on the spindle 9. The rotation position of the magazine body 22 when the grip arm 8 that holds the tool 3 (hereinafter also referred to as the "next tool 3") to be mounted on the spindle 9 is at the spindle position is referred to as the "delivery position B2 of the tool magazine 21". The delivery position B2 is the position where the next tool 3 is delivered from the grip arm 8 to the spindle 9.

[0028] Referring to FIG. 4, the electrical configuration of the numerical control device 40 and the machine tool 1 will be described. The numerical control device 40 includes a control unit 41, a ROM 42, a RAM 43, a storage unit 44, an input / output unit 45, drive circuits 48 to 50, etc. The control unit 41 is connected to the drive circuits 48 to 50 via the input / output unit 45. The control unit 41 includes a CPU etc. and controls the operation of the machine tool 1. The ROM 42 stores a program for executing the main process described later.

[0029] The RAM 43 temporarily stores data generated in various processes. The storage unit 44 is a rewritable storage medium, such as an EPROM, EEPROM, flash memory, etc. The storage unit 44 stores the NC program, the maximum inertia Jb, the maximum unbalanced load Twb, the reference time constant tb, the reference parameter P1, etc. described later.

[0030] The input / output unit 45 performs input / output of various signals among the drive circuits 48 to 50, the encoders 641, 631, 651, the control unit 41, the ROM 42, the RAM 43, the storage unit 44, the operation unit 18, and the display unit 19.

[0031] The drive circuit 48 corresponds to the magazine motor 64, and outputs a pulse signal to the magazine motor 64 based on a command output from the control unit 41. The encoder 641 detects the rotational position of the magazine motor 64. The encoder 641 feeds back the detected rotational position to the drive circuit 48 and the input / output unit 45. The encoder 641 is a general absolute encoder and is a position sensor that detects and outputs the absolute position of the rotational position. The control unit 41 acquires the inertia J and the unbalanced load Tw of the tool magazine 21 during turning based on the feedback information from the encoder 641. The inertia J and the unbalanced load Tw are stored in the storage unit 44 as the acquired inertia J and the acquired unbalanced load Tw, respectively.

[0032] The drive circuits 49 and 50 correspond to the drive motor 63 and the spindle motor 65, respectively, and output pulse signals to the drive motor 63 and the spindle motor 65 based on commands output from the control unit 41. The encoders 631 and 651 detect the rotational positions of the drive motor 63 and the spindle motor 65, respectively. The encoders 631 and 651 feed back the detected rotational positions to the drive circuits 49 and 50 and the input / output unit 45, respectively. The encoders 631 and 651 are general absolute encoders and are position sensors that detect and output the absolute positions of the rotational positions.

[0033] The operation unit 18 receives input of instructions by a user's operation. The display unit 19 displays information to be notified to the user. The display unit 19 is, for example, a liquid crystal touch panel.

[0034] Referring to FIG. 5, a normal synchronized ATC will be described. In tool change, after the spindle 9 passes through the Z-axis origin A1 and before reaching the ATC origin A2, the machine tool 1 starts the turning operation of the tool magazine 21 (see arrow Q1). Before the tool magazine 21 reaches the target position, the machine tool 1 starts the movement operation of the spindle 9 from the ATC origin A2 to the Z-axis origin A1 (see arrow Q2). In this way, the machine tool 1 overlaps the turning operation of the tool magazine 21 and the movement operation of the spindle 9 to shorten the tool change time.

[0035] In the synchronized ATC, an interference area shown in FIG. 5 is set. The interference area indicates the area where the spindle 9 and the tool magazine 21 interfere with each other. For example, when the spindle 9 is rising and the turning of the tool magazine 21 starts too quickly relative to the position of the spindle 9, the tool magazine 21 enters the interference area (see arrow Q3). In this case, for example, the grip arm 8 of the tool magazine 21 or the current tool 3 interferes with the mounting hole 92 of the spindle 9. When the spindle 9 is descending and the descent of the spindle 9 starts too quickly relative to the turning position of the tool magazine 21, the spindle 9 enters the interference area (see arrow Q4). In this case, for example, the mounting hole 92 of the spindle 9 interferes with the grip arm 8 of the tool magazine 21 or the next tool 3. Therefore, the numerical control device 40 needs to perform the movement operation of the spindle 9 and the turning operation of the tool magazine 21 while avoiding entry into the interference area.

[0036] In order to avoid entry into the interference area and achieve shortening of tool change in the synchronized ATC, a time constant t and a parameter P are set. The time constant t is the time constant for acceleration and deceleration of the turning operation of the tool magazine 21. The parameter P indicates the position where the operations of the tool magazine 21 and the spindle 9 can be started. The parameter P includes a first parameter Pa and a second parameter Pb. The first parameter Pa indicates the Z-axis position of the spindle 9 where the turning operation of the tool magazine 21 can be started before the spindle 9 reaches the ATC origin A2. The second parameter Pb indicates the turning position of the tool magazine 21 where the spindle 9 can start the movement operation from the ATC origin A2 to the Z-axis origin A1 before the tool magazine 21 turns to the delivery position B2. Details of the operations will be described later.

[0037] In a normal synchronous ATC, the time constant t is set to the reference time constant tb. The reference time constant tb is a time constant that can operate without exceeding the maximum torque that the magazine motor 64 can output in the reference loading state. The reference loading state is a loading state where the maximum inertia Jb and the maximum unbalance load Twb are determined by the machine specifications. The maximum inertia Jb and the maximum unbalance load Twb are reference loading conditions.

[0038] The parameter P is set to the reference parameter P1. The reference parameter P1 corresponds to the reference time constant tb. The reference parameter P1 includes a first parameter Pa1 and a second parameter Pb1. The first parameter Pa1 indicates the distance from the ATC origin A2 (see Fig. 5). When the main spindle 9 rises, the turning operation of the tool magazine 21 can be started from the position indicated by the first parameter Pa1 (see Fig. 5). The second parameter Pb1 indicates the turning position from the delivery position B2 where the tool magazine 21 completes turning (see Fig. 5). When the main spindle 9 descends, the descending operation of the main spindle 9 can be started from the turning position of the tool magazine 21 indicated by the second parameter Pb1 (see Fig. 5).

[0039] Referring to Fig. 5, the normal synchronous ATC operation will be described. When tool change is started, with the mounting portion 17A of the current tool 3 mounted in the mounting hole 92 of the main spindle 9, the main spindle 9 rises from the machining position of the workpiece fixed to the table 13. In this case, the main spindle 9 moves toward the Z-axis origin A1.

[0040] The cam follower 34 slides down the cam surface of the plate cam 32 of the crank lever 30 from top to bottom. The crank lever 30 rotates counterclockwise in a right-side view about the support shaft 31. The front end of the crank lever 30 engages with the pin 95 from above and presses the draw bar 94 downward. The draw bar 94 biases the clamping portion 93 downward. Therefore, the clamping portion 93 releases the clamping of the pull stud 17B. The grip arm 8 at the main spindle position swings counterclockwise in a right-side view about the fulcrum base 26 as the main spindle 9 rises. The gripping portion 81 of the grip arm 8 releases the clamping by the clamping portion 93. At the same time, the gripping portion 81 of the grip arm 8 grips the current tool 3 mounted on the main spindle 9.

[0041] The main shaft 9 further rises from the Z-axis origin A1 toward the ATC origin A2. The current tool 3 held by the gripping portion 81 detaches from the mounting hole 92 of the main shaft 9. Before the main shaft 9 reaches the ATC origin A2, the magazine motor 64 is driven to start a turning operation of the tool magazine 21 from the receiving position B1 toward the delivery position B2. Specifically, when the main shaft 9 reaches the position indicated by the first parameter Pa1 of the reference parameter P1, the tool magazine 21 starts a turning operation at the reference time constant tb. That is, the tool magazine 21 turns with the next tool 3 to be mounted next toward the main shaft position.

[0042] After the tool magazine 21 starts turning, the main shaft 9 reaches the ATC origin A2. The turning of the tool magazine 21 continues.

[0043] Before the next tool 3 is indexed to the main shaft position, that is, before the tool magazine 21 turns to the delivery position B2, the main shaft 9 starts to descend from the ATC origin A2. Specifically, when the tool magazine 21 turns to the turning position indicated by the second parameter Pb1 of the reference parameter P1, the main shaft 9 starts a descending operation from the ATC origin A2 toward the Z-axis origin A1.

[0044] Thereafter, the tool magazine 21 completes its rotation to the delivery position B2. The next tool 3 is indexed to the spindle position and is disposed below the spindle 9. The spindle 9 continues to descend further toward the Z-axis origin A1. The mounting portion 17A of the holder 17 of the next tool 3 enters the mounting hole 92 of the spindle 9. With the mounting portion 17A inserted into the mounting hole 92, the spindle 9 descends further together with the spindle 9. The cam follower 34 slides on the cam surface of the plate cam 32 from bottom to top. The crank lever 30 rotates clockwise in a right side view about the support shaft 31. The front end portion of the crank lever 30 moves away from the pin 95 upward to release the pressing of the draw bar 94 downward. The draw bar 94 releases the downward biasing of the clamping portion 93. The clamping portion 93 clamps the pull stud 17B of the next tool 3. The next tool 3 is mounted on the spindle 9. The spindle 9 descends further. Accordingly, the gripping portion 81 of the grip arm 8 disengages from the next tool 3 mounted on the spindle 9. Thereby, the tool change from the current tool 3 to the next tool 3 is completed.

[0045] In the above-described synchronized ATC, the spindle 9 and the tool magazine 21 can operate without interference, and the tool change time is shortened as compared with the case where the synchronized ATC is off. In order to further shorten the tool change time, there may be a case where it is desired to shorten the time constant t of the tool magazine 21 from the reference time constant tb to the optimum time constant t1. In this case, the appropriate parameter P changes to the adjusted time constant t1.

[0046] Referring to FIG. 6, the main process will be described. Hereinafter, the description will be made on the premise that the synchronized ATC operation is effective. The user selects and executes a machining program. When the machining program is executed, the control unit 41 executes the main process. When the main process is executed, the control unit 41 specifies the loading condition of the tool magazine 21 (S1). The control unit 41 reads, for example, the loading conditions (maximum inertia Jb, maximum eccentric load Twb) corresponding to the loaded state from the storage unit 44. The user can also set the appropriate loading conditions for the loaded state of the tool magazine 21 by himself / herself.

[0047] The control unit 41 accepts whether to enable or disable the adjustment function of the time constant t (S3). The user operates the operation unit 18 to select whether to enable or disable the adjustment function of the time constant t. The control unit 41 determines whether the adjustment function of the time constant t1 of the tool magazine 21 is enabled (S5). When it is determined that the adjustment function of the time constant t1 of the tool magazine 21 is not enabled (S5: NO), the control unit 41 sets the time constant t1 of the tool magazine 21 to the reference time constant tb (S7). The control unit 41 sets the parameter P of the synchro ATC to the reference parameter P1 (S9).

[0048] The control unit 41 reads a block from the machining program (S19). The control unit 41 determines whether the command of the read block is a tool change command (S21). When it is determined that the command is not a tool change command (S21: NO), the control unit 41 executes the command of the read block. For example, the cutting feed of tool 3 is performed on the workpiece.

[0049] The control unit 41 determines whether the machining program has ended (S23). When it is determined that the machining program has not ended (S23: NO), the control unit 41 returns the process to S19.

[0050] On the other hand, when it is determined that the command is a tool change command (S21: YES), the control unit 41 executes the synchro ATC (S25). In this case, the synchro ATC based on the reference time constant tb set in the process of S7 and the reference parameter P1 set in the process of S9 is executed. The control unit 41 returns the process to S19.

[0051] On the other hand, when it is determined that the adjustment of the time constant t1 of the tool magazine 21 is enabled (S5: YES), the control unit 41 calculates the time constant t1 (S11). The control unit 41 calculates the time constant t1 by using, for example, the following (Equation 1). ·t1 = Jtb / {Jb + tb(|Twb| - |Tw|) / Vmax} (Equation 1) Here, J is the acquired inertia, tb is the reference time constant, Jb is the maximum inertia, Twb is the maximum unbalanced load, Tw is the acquired unbalanced load, and Vmax is the maximum angular velocity. As described above, the maximum inertia jb and the maximum unbalanced load Twb are loading conditions. That is, the time constant t1 is calculated based on the loading conditions specified in the process of S1.

[0052] The control unit 41 sets the time constant t of the tool magazine 21 to the acquired time constant t1 (S13). That is, the control unit 41 sets the acceleration / deceleration time constant t1 in the turning operation of the tool magazine 21 based on the loading conditions of the tool magazine 21.

[0053] The control unit 41 calculates an optimal parameter P2 for the calculated time constant t1 (S15).

[0054] The calculation of the parameter P2 will be described. The parameter P2 includes a first parameter Pac and a second parameter Pbc (see FIG. 7). The first parameter Pac is calculated by using the following (Equation 2). ·Pac = Pa1 + (tb - t1) × D1 ··· (Equation 2) Here, tb is the reference time constant, Pa1 is the first parameter of the reference parameter P1, t1 is the time constant, and D1 is the change rate. For example, when Pa1 = 30, tb = 100, t1 = 70, and D1 = -0.2, the first parameter Pa is 30 + (100 - 70) × -0.2 = 24. The first parameter Pa indicates a position 24 mm away from the ATC origin A2. This position is the position where the turning operation of the tool magazine 21 can be started.

[0055] Here, the change rate D1 can be obtained from the correspondence relationship between the time constant t and the parameter P shown in FIG. 8. For example, in FIG. 8, the value of the first parameter Pa1 corresponding to the reference time constant tb is plotted. Also, the values of the first parameters Pa2 and Pb3 corresponding to the shortened time constants tA and tB after shortening the time constant t are plotted respectively. The relationships between the time constants tb, tA, tB and the first parameters Pa1, Pa2, Pa3 have been obtained in advance through experiments or the like. The change rate D1 is the slope when linearly interpolating these plotted relationships. The change rate D1 is, for example, stored in advance in the storage unit 44. The change rate D1 is information indicating the correspondence relationship between the time constant t and the parameter P. Incidentally, for example, when the time constant t is shortened from the reference time constant tb, when the main shaft 9 rises, the startable position of the turning operation of the tool magazine 21 needs to be set closer to the ATC origin A2 than the startable position of the turning operation of the tool magazine 21 at the reference time constant tb. Therefore, the relationship D1 < 0 holds.

[0056] On the other hand, the second parameter Pbc is calculated by using the following (Equation 3). ·Pbc = Pb1 + (tb - t1) × D2 ··· (Equation 3) Here, tb is the reference time constant, Pb1 is the second parameter of the reference parameter P1, t1 is the time constant, and D2 is the change rate. The position indicated by the second parameter Pbc indicates the turning position with respect to the delivery position B2. This position is the position where the downward movement of the main shaft 9 can be started. Incidentally, the change rate D2 can be obtained from the correspondence relationship between the time constant t and the parameter P shown in FIG. 9. Specifically, the change rate D2 is the slope when performing linear interpolation on the plot results of FIG. 9. The change rate D2 is, for example, stored in advance in the storage unit 44. The change rate D2 is information indicating the correspondence relationship between the time constant t and the parameter P. Incidentally, for example, when the time constant t1 is shortened from the reference time constant tb, the turning position of the tool magazine 21 where the downward movement of the main shaft 9 can be started can be set farther from the delivery position B2 than the turning position of the tool magazine 21 where the downward movement of the main shaft 9 can be started at the reference time constant tb. Therefore, the relationship D2 > 0 holds.

[0057] The control unit 41 sets the parameter P to the parameter P2 obtained by calculating the parameter P (S17). That is, the control unit 41 sets the parameter P2 based on the set time constant t1. The control unit 41 proceeds with the process to S19.

[0058] Here, in the process of S21, if it is determined that it is a tool change command (S21: YES), the control unit 41 executes the synchronous ATC based on the time constant t1 set in the process of S13 and the parameter P2 set in the process of S17 (S25). As shown in FIG. 7, when the time constant t1 is set to be shorter than the reference time constant tb, the control unit 41 starts the turning operation of the tool magazine 21 from the receiving position B1 to the delivery position B2 at a position of the spindle 9 closer to the ATC origin A2 than the position of the spindle 9 when starting the turning operation of the tool magazine 21 with the reference time constant tb (see arrow Q5 in FIG. 7). In this case, when the spindle 9 descends, the control unit 41 starts the movement operation of the spindle 9 from the ATC origin A2 to the Z-axis origin A1 at a position of the tool magazine 21 where the turning position of the tool magazine 21 is farther from the delivery position B2 than the turning position of the tool magazine 21 when starting the movement operation of the spindle 9 with the reference time constant tb (see arrow Q6 in FIG. 7). Thereby, the control unit 41 can obtain the shortening effect from the reference time constant tb to the time constant t1 and can realize the synchronous ATC operation with the optimal parameter P.

[0059] After the tool change is completed in S25, the control unit 41 returns the process to S19.

[0060] On the other hand, if it is determined that the machining program has ended (S23: YES), the control unit 41 ends the main process.

[0061] As described above, the control unit 41 sets the time constant t1 of the acceleration / deceleration in the turning operation of the tool magazine 21 based on the loading condition of the tool magazine 21. The control unit 41 sets the parameter P based on the set time constant t1. In the tool change, the control unit 41 executes the turning operation of the tool magazine 21 and the movement operation of the spindle 9 based on the set time constant t1 and the set parameter P.

[0062] Even when the tool magazine 21 is rotated with the time constant t1 optimized according to the loading conditions of the tool 3 during tool change, the tool magazine 21 and the spindle 9 can operate based on appropriate parameters P. Also, if the parameter P is not set to an appropriate value for the set time constant t1, there is a possibility that the tool magazine 21 and the spindle 9 may interfere. In this case, it is conceivable that the numerical control device 40 further performs acceleration / deceleration of the tool magazine 21 to avoid interference between the tool magazine 21 and the spindle 9. However, when this turning operation is executed, the load on the speed reducer 25 for turning the tool magazine 21 increases. Since the numerical control device 40 does not need to perform further acceleration / deceleration to avoid interference, it can reduce the possibility of an increase in the load on the speed reducer 25 of the tool magazine 21.

[0063] The loading conditions are defined by the maximum inertia Jb and the maximum eccentric load Twb around the turning axis 23 of the tool magazine 21. The numerical control device 40 can set the time constant t1 based on the maximum inertia Jb and the eccentric load Twb.

[0064] The storage unit 44 stores change rates D1 and D2 indicating the correspondence between the time constant t and the parameter P. The control unit 41 sets the parameter P based on the set time constant t1 and the change rates D1 and D2 stored in the storage unit 44.

[0065] The time constant t includes a reference time constant tb corresponding to the maximum inertia Jb and the maximum eccentric load Twb. The parameter P includes a reference parameter P1 corresponding to the reference time constant tb. The information indicating the correspondence is the change rates D1 and D2 of the parameter P with respect to the variation of the time constant t. The control unit 41 calculates a parameter P2 based on the reference time constant tb, the reference parameter P1, the set time constant t1, and the change rates D1 and D2. The numerical control device 40 can obtain the parameter P2 by calculation.

[0066] The parameter P includes a first parameter Pa and a second parameter Pb. The first parameter Pa indicates the position of the spindle 9 at which the turning operation of the tool magazine 21 can be started before the spindle 9 reaches the ATC origin A2. The second parameter Pb indicates the turning position of the tool magazine 21 at which the spindle 9 can start moving from the ATC origin A2 toward the Z-axis origin A1 before the tool magazine 21 turns to the delivery position B2. The numerical control device 40 can control the operations of the tool magazine 21 and the spindle 9 based on the first parameter Pa and the second parameter Pb.

[0067] The time constant t1 includes a reference time constant tb corresponding to the maximum inertia Jb and the maximum unbalanced load Twb. When the control unit 41 is set to the time constant t1 shortened with respect to the reference time constant tb, the turning operation of the tool magazine 21 from the receiving position B1 to the delivery position B2 starts at a position of the spindle 9 closer to the ATC origin A2 than the position of the spindle 9 when the turning operation of the tool magazine 21 starts with the reference time constant tb. The control unit 41 starts the movement operation of the spindle 9 from the ATC origin A2 toward the Z-axis origin A1 at a turning position of the tool magazine 21 farther from the delivery position B2 than the turning position of the tool magazine 21 when the movement operation of the spindle 9 starts with the reference time constant tb. The numerical control device 40 can shorten the time required for tool change by shortening the time constant t from the reference time constant tb.

[0068] The control unit 41 accepts valid or invalid for the adjustment of the time constant t. In the above numerical control device, the user can change the time constant t as needed.

[0069] In the above description, the Z-axis origin A1 is an example of an "exchange position". The ATC origin A2 is an example of a "separation position". The maximum inertia Jb and the maximum unbalanced load Twb are examples of "loading conditions". The change rates D1 and D2 are examples of "information". The control unit 41 that executes the process of S13 is an example of a "time constant setting process". The control unit 41 that executes the process of S17 is an example of a "parameter setting process". The control unit 41 that executes the process of S25 is an example of an "operation control process". The control unit 41 that executes the process of S11 is an example of a "calculation process". The control unit 41 that executes the process of S3 is an example of a "reception process".

[0070] The present invention is not limited to the above-described embodiments, and various modifications are possible. Although the machine tool 1 is an upright machine tool in which the axial direction of the main shaft 9 extends in the vertical direction, it may be a horizontal machine tool in which the axial direction of the main shaft 9 extends in the front-rear direction.

[0071] In the above embodiment, it is assumed that the time constant t1 is shortened from the reference time constant tb, but it is not limited to this. For example, it may be assumed that the time constant t1 is increased. Even in this case, the numerical control device 40 can set an appropriate parameter P2 according to the time constant t.

[0072] The first parameter Pa and the second parameter Pb respectively correspond to the Z-axis position of the main shaft 9 and the turning position of the tool magazine 21, but it is not limited to this. For example, the first parameter Pa and the second parameter Pb may be based on the elapsed time since the start of tool exchange. Even in this case, the numerical control device 40 can obtain the same effects as in the above embodiment.

[0073] In the above embodiment, the parameter Pb indicates the rotatable position of the tool magazine 21 when the main shaft 9 ascends, but it is not limited to this. For example, even when the time constant t is adjusted, the turning position of the tool magazine 21 when the main shaft 9 ascends may not be changed. For example, when the main shaft 9 moves up and down, the moving speed of the main shaft 9 may be changed according to the adjusted time constant t1. That is, as the parameter Pac, the moving speed, acceleration, etc. of the main shaft 9 may be used. When the main shaft 9 descends, the moving speed, acceleration, moving start time, etc. of the main shaft 9 may be changed according to the adjusted time constant t.

[0074] In the above embodiment, the loading conditions are defined by the maximum inertia Jb and the maximum unbalance load Twb, but it is not limited to this. For example, the loading conditions may be defined by at least one of the maximum inertia Jb and the maximum unbalance load Twb around the turning axis 23 of the tool magazine 21. Also, the loading conditions may be defined by at least one of the acquired inertia J and the acquired unbalance load Tw. That is, the loading conditions may be changed as appropriate.

[0075] In the above embodiment, the torque in the reference loading state was the maximum output of the magazine motor 64, but it is not limited to this. For example, the torque in the reference loading state may not be the maximum output of the magazine motor 64. Also, the reference time constant tb may be the time constant t determined in consideration of the life of the speed reducer 25 and torque shortage.

[0076] In the above embodiment, the time constant t1 was calculated by the control unit 41, but it is not limited to this. For example, the time constant t1 may be set by the user operating the operation unit 18 within a settable range. Also, the correspondence relationship between the loading conditions and the optimal time constant t1 may be stored in the storage unit 44 as a table in advance. For example, the table may be based on FIGS. 8, 9, (Equation 1). As the "information indicating the correspondence relationship" of the present invention, a table, a mathematical formula, etc. may be targeted. The time constant t1 was calculated by (Equation 1), but other mathematical formulas may be used. In (Equation 1), both the maximum inertia Jb and the maximum unbalance load Twb were used as the loading conditions, but the time constant t1 may be calculated using only one of them.

[0077] In the above embodiment, the parameter P is set based on the loading conditions, but it is not limited to this. For example, the control unit 41 may set the loading conditions and the parameters P1 and P2 by paying attention to the total weight of the tools 3 loaded in the tool magazine 21. In this case, the storage unit 44 stores the maximum inertia Jb and the maximum eccentric load Twb when the total weight is equal to or greater than a predetermined value, and the maximum inertia Jb and the maximum eccentric load Twb when the total weight is less than the predetermined value. The control unit 41 sets different parameters P1 and P2 depending on, for example, whether the total weight of the tools 3 loaded in the tool magazine 21 is equal to or greater than a predetermined value or less than the predetermined value. The predetermined value may be determined as appropriate. In the above numerical control device, an appropriate parameter P can be set according to the total weight of the tools loaded in the tool magazine 21.

Explanation of Signs

[0078] 1 Machine tool 3 Tool, current tool, next tool 9 Spindle 21 Tool magazine 23 Swivel axis 40 Numerical control device 41 Control unit 44 Storage unit 63 Drive motor 64 Magazine motor A1, A2, B1, B2 Positions t, tb, t1 Time constants J, jb Inertias Tw, Twb Eccentric loads D1, D2 Rates of change P, P1, P2 Parameters Pa, Pa1, Pac First parameters Pb, Pb1, Pbc Second parameters

Claims

1. A numerical control device for controlling a machine tool including a spindle that can mount a tool and is movable between an exchange position where the tool is exchanged by driving a drive motor and a separated position separated from the exchange position, and a tool magazine that can load the tool and is rotatable about a rotation axis by driving a magazine motor in tool exchange, between a receiving position for receiving the tool mounted on the spindle and a delivery position for delivering the tool to be mounted on the spindle to the spindle The numerical control device includes: a control unit that controls the operations of the spindle and the tool magazine by outputting commands to the drive motor and the magazine motor The numerical control device further includes: The control unit Performs a time constant setting process of setting a time constant for acceleration and deceleration in the rotation operation of the tool magazine based on the loading condition of the tool magazine; A parameter setting process of setting parameters for starting the rotation operation of the tool magazine after the tool magazine receives the tool from the spindle at the receiving position and before the spindle reaches the separated position, and starting the movement operation of the spindle from the separated position to the exchange position before the tool magazine rotates to the delivery position, based on the time constant set in the time constant setting process; An operation control process of executing the rotation operation of the tool magazine and the movement operation of the spindle based on the time constant set in the time constant setting process and the parameters set by the parameter setting process during tool exchange The numerical control device executes the above processes Characterized in that.

2. The loading condition is defined by at least one of the inertia and the unbalance load of the tool magazine about the rotation axis. The numerical control device according to claim 1, characterized in that.

3. The numerical control device includes a storage unit that stores information indicating the correspondence between the time constant and the parameter, and The parameter setting process executes an arithmetic process of setting the parameter based on the time constant set in the time constant setting process and the information stored in the storage unit. The numerical control device according to claim 1, characterized in that.

4. The time constant includes a reference time constant corresponding to the maximum inertia and the maximum unbalance load of the tool magazine, The parameter includes a reference parameter corresponding to the reference time constant, The information is the change rate of the parameter with respect to the variation of the time constant. The arithmetic processing calculates the parameter based on the reference time constant, the reference parameter, the time constant set by the time constant setting process, and the change rate The numerical control device according to claim 3, characterized in that

5. The parameter is a first parameter indicating a position of the spindle at which the turning operation of the tool magazine can be started before the spindle reaches the separated position, and a second parameter indicating a turning position of the tool magazine at which the spindle can start the moving operation from the separated position toward the exchange position before the tool magazine turns to the delivery position including The numerical control device according to claim 1, characterized in that

6. The time constant includes a reference time constant corresponding to the maximum inertia and the maximum unbalanced load of the tool magazine, The operation control process when the time constant is set to be shorter than the reference time constant by the time constant setting process, the turning operation of the tool magazine from the receiving position to the delivery position starts at a position of the spindle closer to the separated position than the position of the spindle when the turning operation of the tool magazine starts with the reference time constant, and the turning position of the tool magazine when the moving operation of the spindle from the separated position to the exchange position starts starts the moving operation of the spindle at a position farther from the delivery position than the turning position of the tool magazine when the moving operation of the spindle starts with the reference time constant The numerical control device according to claim 1, characterized in that

7. The control unit executes a reception process for receiving validity or invalidity regarding the execution of the time constant setting process executing The numerical control device according to claim 1, characterized in that

8. The parameter setting process sets different parameters depending on whether the total weight of the tools loaded in the tool magazine is equal to or greater than a predetermined value and whether the total weight of the tools loaded in the tool magazine is less than the predetermined value The numerical control device according to claim 1, characterized in that

9. a spindle that can mount a tool and is movable between an exchange position where the tool is exchanged by driving a drive motor and a separated position separated from the exchange position in a tool exchange for exchanging the tool The tool magazine is capable of loading the tool, and in the tool change, by rotating around the rotation axis by driving the magazine motor, it can rotate between a receiving position for receiving the tool mounted on the spindle and a delivery position for delivering the tool to be mounted on the spindle to the spindle. A control method for a numerical control device that controls a machine tool having the above components and outputs commands to the drive motor and the magazine motor to control the operations of the spindle and the tool magazine, a time constant setting step of setting a time constant for acceleration and deceleration in the turning operation of the tool magazine based on the loading conditions of the tool magazine; a parameter setting step of setting parameters for starting the turning operation of the tool magazine after the tool magazine receives the tool from the spindle at the receiving position and before the spindle reaches the separated position, and starting the moving operation of the spindle from the separated position to the exchange position before the tool magazine rotates to the delivery position, based on the time constant set in the time constant setting step; an operation control step of executing the turning operation of the tool magazine and the moving operation of the spindle based on the time constant set in the time constant setting step and the parameters set in the parameter setting step in the tool change; is executed This is a characteristic of the control method.

10. A spindle that can mount a tool and can move between an exchange position for exchanging the tool by driving a drive motor and a separated position separated from the exchange position in the tool change for exchanging the tool, The tool magazine is capable of loading the tool, and in the tool change, by rotating around the rotation axis by driving the magazine motor, it can rotate between a receiving position for receiving the tool mounted on the spindle and a delivery position for delivering the tool to be mounted on the spindle to the spindle. In a computer of a numerical control device that controls a machine tool having the above components and outputs commands to the drive motor and the magazine motor to control the operations of the spindle and the tool magazine, a time constant setting step of setting a time constant for acceleration and deceleration in the turning operation of the tool magazine based on the loading conditions of the tool magazine; After the tool magazine receives the tool from the spindle at the receiving position, a parameter for starting the turning operation of the tool magazine before the spindle reaches the separation position and for starting the movement operation of the spindle from the separation position to the exchange position before the tool magazine turns to the delivery position is set based on the time constant set in the time constant setting step; a parameter setting step; An operation control step of executing the turning operation of the tool magazine and the movement operation of the spindle based on the time constant set in the time constant setting step and the parameter set in the parameter setting step in the tool change; A program characterized by causing the above to be executed.

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