CN108241341A - Numerical control device and control method - Google Patents

Abstract

The present invention relates to a kind of numerical control device and control methods.The CPU of numerical control device determines whether that the current action that the energization of spindle motor is off-state and lathe is axis movement.When it be the current action of off-state and lathe is axis movement to be judged as being powered, whether CPU, which judges to rotate comprising main shaft in the move of next action generated, instructs.When being judged as in the move of next action comprising main shaft rotation instruction, the energization of spindle motor is switched to on-state by CPU before axis movement is completed from off-state.Therefore, numerical control device can shorten the stand-by time until spindle motor is turned on rotating main shaft in next action.

Description

Numerical control device and control method

technical field

The invention relates to a numerical control device and a control method.

Background technique

In a machine tool equipped with a tool changer, the spindle motor is stopped and the tool attached to the spindle is replaced with another tool, and then the spindle is rotated again to restart machine processing. In the spindle motor control method disclosed in Japanese Patent Laying-Open No. 80172 of 1984, when performing tool replacement, the spindle motor is stopped at a target position, and the spindle in the stopped state is locked to the main body of the device. In the spindle motor control method, the excitation of the spindle motor is turned off during a part of the spindle lock period to prevent the spindle motor from heating even if the spindle is forcibly changed by external force during the lock period. In the spindle motor control method, after another tool is mounted on the spindle, the excitation of the spindle motor is turned ON to rotate the spindle again.

It takes a predetermined time from when the excitation of the spindle motor is turned off until when the excitation is turned on and the spindle motor can be rotated. Therefore, conventionally, there has been a problem in that the start of rotation of the spindle is delayed by the predetermined time during an operation accompanying tool replacement.

Contents of the invention

An object of the present invention is to provide a numerical control device and a numerical control device capable of rapidly starting the rotation of the main shaft in the next operation even if the energization (excitation) of the motor for driving the main shaft is off during the current operation. Control Method.

The numerical control device of claim 1 includes a control unit that interprets a control command of the NC program to generate an internal command, and controls the operation of the device according to the generated internal command. In the numerical control device, the device has A spindle for mounting a tool, wherein the control unit includes: a first judging unit that judges whether the power supply to the motor for rotationally driving the spindle is off and the current operation of the device is shaft movement. the second judging part, when the first judging part judges that the power supply of the motor is off and the current action is shaft movement, the second judging part judges that the internal command in the next action whether the main shaft rotation command for rotating the main shaft is included in; and the energization control unit determines that the main shaft rotation command is included in the internal command for the next operation when the second determination unit determines that the main shaft rotation command is included. The energization control unit switches energization of the motor from an off state to an on state before the movement of the shaft is completed. It takes time to switch the motor for driving the spindle from the off state to the on state. When the current operation is axis movement and the spindle rotation command is included in the internal command for the next operation, the numerical controller switches the power supply to the motor from OFF to ON before the axis movement as the current operation is completed. Therefore, the numerical control device can shorten the standby time until the motor turns on and the main shaft can rotate in the next operation. When the motor for rotationally driving the main shaft is not used, in principle, the power supply to the motor should be turned off. Therefore, the numerical controller can consume the power consumed by the equipment.

The control unit of the numerical control device according to claim 2 may further include a rotation execution unit configured to execute the next operation after the shaft movement is completed after the energization control unit turns on the energization of the motor. When the internal command is issued, the rotation execution unit executes the spindle rotation command. The numerical controller does not rotate the main shaft until the next internal command is executed even if the motor is turned on before the movement of the axis is completed. Assume that the spindle is in a stopped state when the machine is stopped at the point in time when the axis movement is completed. Therefore, the numerical control device prevents the main shaft from being rotated, thereby improving the safety of work.

In the numerical control device according to claims 3 and 4, the control unit may generate an axis movement command when the control command of the NC program is a tapping command for performing tapping on a workpiece. , a cutting feed command, and an exit command are used as the internal commands. The axis movement command is used to move the axis from the current position to the reference point when the power to the motor is turned off. The reference point is at the The position at which machining starts in the workpiece, the cutting feed command includes the spindle rotation command for rotating the spindle, and is used to rotate the spindle according to the spindle rotation command from the reference point to the The cutting feed is performed at the target position of the workpiece, and the exit command is used to make the spindle direction and the rotation direction during the cutting feed after the cutting feed is carried out to the target position. Rotate in the opposite direction and perform shaft movement for withdrawing the main shaft from the hole formed in the workpiece, and the first judging unit judges that the energization of the motor is off and the The current operation is an axis movement corresponding to the axis movement command, and the second determination unit determines that the spindle rotation command is included in the cutting feed command as the internal command for the next operation. , the energization control unit switches the energization of the motor from the OFF state to the ON state before the axis movement to the reference point as the current operation is completed. When the control unit interprets the tapping command, it generates three internal commands of an axis movement command, a cutting feed command, and an exit command. When the motor is turned off during the execution of the axis movement command from the current position to the reference point, the internal command for the next operation is a cutting feed command including a spindle rotation command. Therefore, the numerical controller can switch the energization of the motor from the OFF state to the ON state before the axis movement to the reference point is completed. Therefore, the numerical control device can also shorten the standby time until the motor is turned on and the main shaft is rotated when the tapping operation is performed.

The device controlled by the control unit of the numerical control device according to claims 5 to 8 may include: a spindle head that supports the spindle in a rotatable manner and is provided so as to be able to move vertically in the vertical direction. moving; and a tool magazine, the tool magazine rotates and supports a tool when the spindle head is located at an ATC origin, the ATC origin is a position above the equipment origin within the movement range of the spindle head in the up and down direction, The device is capable of performing a tool replacement action, and the tool replacement action includes the following actions: a first lifting action, which makes the spindle head rise from the current position to the origin of the device; a second lifting action, which makes the spindle head rise from the The origin of the equipment rises to the origin of the ATC. During this period, the current tool currently installed on the spindle is removed and handed over to the tool magazine; when the spindle head is at the origin of the ATC, the rotation action makes the The tool magazine rotates to position the next tool to be installed on the main shaft to face the main shaft; the first descending action makes the main shaft head descend from the ATC origin to the equipment origin, during which , receiving the next tool from the tool magazine and installing it on the spindle; and a second descending action, causing the spindle head to descend from the origin of the device to a target position, during which time the spindle is rotated, When the control command of the NC program is a tool replacement command for instructing the tool replacement operation, the generator generates a first ascending command, a second ascending command, a rotation command, a first descending command, and a second A descending command is used as the internal command, the first ascending command is used to instruct the shaft movement of the first ascending action, the second ascending command is used to indicate the shaft movement of the second ascending action, and the rotation The command is used to indicate the rotation action, the first lowering command is used to indicate the shaft movement of the first lowering action, and the second lowering command is used to indicate the shaft movement of the second lowering action, and includes The main shaft rotation command for the main shaft rotation is judged by the first judging unit that the energization of the motor is off and the current operation is a shaft movement corresponding to the first lowering command, and the When the second determination unit determines that the second lowering command as the internal command for the next operation includes the main shaft rotation command, the direction of the energization control unit during the first lowering operation The energization of the motor is switched from an off state to an on state before the axis movement of the origin of the device is completed. The control unit interprets the tool replacement command, and generates a first ascending command, a second ascending command, a rotation command, a first descending command, and a second descending command as internal commands. The second descending command is a command including a spindle rotation command. Therefore, when the numerical control device executes the first lowering command, when the internal command for the next operation is the second lowering command, it is possible to stop the power supply of the motor from The off state is switched to the on state. Therefore, the numerical control device can also shorten the standby time until the motor is turned on and the main shaft is rotated when the tool replacement operation is performed.

The numerical control device according to claim 9 may further include a setting unit capable of setting an upper limit value of a range that is compared with that of the spindle attachment during the first lowering operation. In the range where the energization control unit can switch the energization of the motor from the off state to the on state within the range below the predetermined position of the cutter and above the origin of the device, the first determination unit judges The energization of the motor is off and the current operation is shaft movement corresponding to the first lowering command, and the second determination unit determines that the internal command that is the next operation is When the spindle rotation command is included in the second lowering command, and the upper limit value set by the setting unit is equal to or smaller than the upper limit value set by the setting unit during the first lowering operation, the energization control unit sends Before the axis movement of the origin of the device is completed, the energization of the motor is switched from the OFF state to the ON state. The numerical controller can set an upper limit value of a range in which energization of the motor can be switched from an off state to an on state within a range below the predetermined position and above the origin of the device during the first lowering operation. When the predetermined position is reached, the motor of the main shaft is turned off, and the torque of the motor is not applied to the main shaft. Therefore, the numerical controller prevents the torque of the motor from affecting the equipment when the predetermined position is reached.

The control method in claim 10 is a control method of a numerical control device, including a control step in which an internal command is generated by interpreting a control command of the NC program, and the internal command is executed according to the generated internal command. In the control method, the control step includes the following steps: a first judging step, judging whether it is the energization of the motor for rotationally driving the main shaft is in an off state and the current action of the device controlled in the control step is shaft movement; in the second judging step, it is judged in the first judging step that the energization of the motor is in an off state and the When the current action is axis movement, it is judged whether the internal command for the next action includes a spindle rotation command for rotating the spindle; When the internal command for the next operation includes the main shaft rotation command, the power supply to the motor is switched from the OFF state to the ON state before the shaft movement is completed. The numerical control device can obtain the effects described in claims 1 to 9 by performing the above steps.

In the present invention, a part of the invention-specific matters of the above-mentioned claims 1 to 9 may be arbitrarily combined.

Description of drawings

FIG. 1 is a perspective view of a machine tool 1 .

FIG. 2 is a partial cross-sectional view around the spindle head 7 .

Fig. 3 is a route diagram of a tool replacement operation.

FIG. 4 is a partial cross-sectional view around the spindle head 7 during the lifting operation of the spindle head 7 .

FIG. 5 is a partial cross-sectional view around the spindle head 7 during the up-and-down operation of the spindle head 7 .

FIG. 6 is a partial cross-sectional view around the spindle head 7 during the lifting operation of the spindle head 7 .

FIG. 7 is a partial cross-sectional view around the spindle head 7 during the up-and-down operation of the spindle head 7 .

FIG. 8 is a block diagram showing the electrical configuration of the machine tool 1 and the numerical control device 30 .

FIG. 9 is a diagram in which acceleration and deceleration processing is applied to the speed block B1.

FIG. 10 is a timing chart showing the output of the spindle motor ON command in the basic operation mode.

FIG. 11 is a table showing target operation modes A to G.

Fig. 12 is a flowchart of movement control processing.

FIG. 13 is a flowchart showing a continuation of FIG. 12 .

FIG. 14 is a timing chart of Mode A. FIG.

FIG. 15 is a timing chart of mode B.

Fig. 16 is a path diagram of a tapping operation.

FIG. 17 is a timing chart of mode C.

FIG. 18 is a timing chart of Mode D. FIG.

FIG. 19 is a time chart of mode G.

Fig. 20 is a path diagram of the drilling operation.

Detailed ways

Embodiments of the present invention will be described. In the following description, left and right, front and rear, and up and down indicated by arrows in FIG. 1 are used. The left-right direction, front-rear direction, and up-down direction of the machine tool 1 are the X-axis direction, the Y-axis direction, and the Z-axis direction of the machine tool 1 , respectively.

The configuration of the machine tool 1 will be described with reference to FIG. 1 . The machine tool 1 includes a base 2 , an equipment main body 3 , a table 10 , a tool changing device 20 , and the like. The base 2 is a substantially cuboid iron base. The equipment main body 3 is provided behind the upper part of the base 2 and is used for cutting a workpiece (not shown) held on the upper surface of the table 10 . The table 10 is provided at the upper center of the base 2, and is movable in the X-axis direction and the Y-axis direction by an X-axis motor 51, a Y-axis motor 52 (see FIG. 8 ) and a guide mechanism (not shown). The tool changer 20 is fixed to the frame 8 provided on the upper part of the equipment main body 3, and is used to replace the tool 4 mounted on the main shaft 9 of the equipment main body 3 with another tool (hereinafter referred to as the next tool).

The machine tool 1 includes an operation panel 15 (see FIG. 8 ). The operation panel 15 includes an input unit 24 and a display unit 25 . A worker inputs an NC program, a tool type, tool information, various parameters, and the like through the input unit 24 . When a worker operates the input unit 24 , the display unit 25 displays various input screens, operation screens, and the like.

The configuration of the device main body 3 will be described with reference to FIGS. 1 and 2 . The device main body 3 includes a column 5, a spindle head 7, a spindle 9, a control box 6, and the like. The column 5 is vertically arranged behind the upper part of the abutment 2 . The spindle head 7 can be raised and lowered along the Z-axis direction along the front surface of the column 5 . A tool holder 17 (see FIG. 2 ) is attached to the spindle 9 , and the spindle 9 is driven to rotate at high speed by a spindle motor 54 . The spindle motor 54 is arranged on the top of the spindle head 7 . The knife holder 17 serves to hold the knife 4 . The control box 6 houses a numerical controller 30 (see FIG. 8 ). The numerical controller 30 controls the operation of the machine tool 1 .

The spindle head 7 is raised and lowered in the Z-axis direction by a Z-axis moving mechanism provided on the front surface of the column 5 . The Z-axis moving mechanism includes a pair of Z-axis guide mechanisms (not shown), a Z-axis ball screw 26 , and a Z-axis motor 53 (see FIG. 8 ). The Z-axis guide mechanism extends in the Z-axis direction and guides the spindle head 7 in the Z-axis direction. The Z-axis ball screw 26 is disposed between a pair of Z-axis guide mechanisms, and is provided rotatably via an upper bearing portion 27 and a lower bearing portion (not shown). The spindle head 7 is provided with a nut 29 on the back. The nut 29 is threadedly combined with the Z-axis ball screw 26 . The Z-axis motor 53 rotates the Z-axis ball screw 26 in forward and reverse directions. Therefore, the spindle head 7 moves in the Z-axis direction together with the nut 29 . The spindle head 7 rotatably supports the spindle 9 inside the front lower portion. The main shaft 9 has a rotation axis extending in the vertical direction. The spindle 9 is connected to the drive shaft of the spindle motor 54 via the connection portion 23 . Therefore, the spindle 9 is rotated by the rotation drive of the spindle motor 54 . The main shaft 9 is provided with a tapered hole 18 , a holder holding member 19 , and a draw bar 81 . The tapered hole 18 is provided at the top end (lower end) of the main shaft 9 . The holder clamping member 19 is disposed above the tapered hole 18 . The draw bar 81 is arranged inside the main shaft 9 . The tool holder 17 holds the tool 4 on one end side, and has a tapered mounting portion 17A and a pull stud 17B on the other end side. The tapered mounting portion 17A has a substantially conical shape. A draw bolt 17B axially protrudes from the top of the tapered mounting portion 17A. The tapered mounting portion 17A is mounted on the tapered hole 18 of the main shaft 9 . When the tapered mounting portion 17A is mounted to the tapered hole 18 , the holder holding member 19 holds the pull bolt 17B. When the draw bar 81 presses the holder clamping member 19 downward, the holder clamping member 19 releases the clamping of the draw bolt 17B. The spindle head 7 is provided with a rod member 60 inside the rear upper portion. The lever member 60 has a substantially L-shape and is free to swing around the support shaft 61 . The supporting shaft 61 is fixed inside the spindle head 7 . The rod member 60 includes a longitudinal rod 63 and a lateral rod 62 . The longitudinal rod 63 extends obliquely upward relative to the side of the column 5 from the support shaft 61 , then bends upward at the middle portion 65 and further extends upward. The transverse rod 62 extends substantially horizontally from the support shaft 61 toward the main shaft 9 side. The front end portion of the transverse rod 62 can engage with the pin 58 protruding perpendicularly to the draw bar 81 from above the pin 58 . The longitudinal bar 63 is provided with a plate cam body 66 on the back of the upper end. The plate cam body 66 has a cam surface on the column 5 side. The cam surface of the plate cam body 66 is capable of contacting and separating from the cam follower 67 fixed to the upper bearing portion 27 . The cam follower 67 slides on the cam surface of the plate cam body 66 . A tension coil spring (not shown) is elastically provided between the longitudinal rod 63 and the spindle head 7 . When viewing the lever member 60 from the right side, the tension coil spring always urges the lever member 60 in the clockwise direction. Therefore, the lever member 60 always releases the downward pressing of the pin 58 by the horizontal lever 62 . The tool changing device 20 includes a tool magazine 21 . The tool magazine 21 includes a disk-shaped tool magazine base 71 and a plurality of grip arms 90 . A plurality of grip arms 90 are provided along the outer periphery of the tool magazine base 71 so as to be swingable in the front-rear direction. The tool magazine supporting platform 45 is fixed on one end of the frame 8 . The other end of the frame 8 is fixed to the column 5 . The tool magazine support 45 supports the spindle 75 so that the spindle 75 can rotate. The support shaft 75 extends obliquely downward with respect to the front of the machine tool 1 . The support shaft 75 supports the magazine base 71 in a rotatable manner. The magazine base 71 is arranged so that the front faces the front of the machine tool 1 .

The tool replacement operation will be described with reference to FIGS. 3 to 7 . In the following description, the device origin of the Z-axis is referred to as the Z-axis origin. The machine origin is a position where the machine coordinates of the X-axis and the Y-axis are zero, and is a position where the machine coordinates of the Z-axis are the upper limit position where a workpiece can be machined. In this embodiment, for convenience of description, the target position (processing position) is assumed to be Z200, the current position is assumed to be Z300, the Z-axis origin is assumed to be Z400, and the ATC origin is assumed to be Z500 (see FIG. 3 ). The area closer to the table 10 than the Z-axis origin is the machining area, and the area opposite the Z-axis origin to the machining area is the tool replacement area. The machining area is an area for performing machining operations on workpieces. The tool changing area is an area for tool changing by the tool changing device 20 . The unit of each figure is mm. The tool replacement operation includes a first step 101 to a fifth step 105 . As shown in FIG. 4 , the first step 101 is to move the spindle head 7 from the current position (for example, the processing position) toward the Z-axis in the state where the tapered mounting portion 17A of the tool holder 17 is mounted on the tapered hole 18 of the spindle 9 . This is a process of performing an orienting operation of the main shaft 9 by raising the origin. The orientation operation is an operation for stopping the rotational angular position of the main shaft 9 at a predetermined position. The second step 102 is a step of raising the spindle head 7 from the Z-axis origin toward the ATC origin and turning off the power supply of the spindle motor 54 . At a predetermined position between the Z-axis origin and the ATC origin, the plate cam body 66 provided on the lever member 60 contacts and slides with the cam follower 67 . As shown in FIG. 5 , the grip portion 91 of the grip arm 90 grips the knife holder 17 , and the cam follower 67 slides along the cam shape of the plate cam body 66 . The lever member 60 rotates counterclockwise around the support shaft 61 when viewed from the right side. The horizontal bar 62 engages with the pin 58 from above and presses the draw bar 81 downward. The draw bar 81 biases the holder holding member 19 downward. The holder clamping member 19 releases the clamping of the pull bolt 17B.

As shown in the order of FIGS. 6 and 7 , the spindle head 7 is further raised. The tool holder 17 emerges from the tapered hole 18 of the spindle 9 . The removal of the tool holder 17 from the tapered hole 18 of the spindle 9 is complete. As described above, in the second step 102, the spindle motor 54 is turned off. Therefore, the machine tool 1 prevents the mechanical mechanism for attaching and detaching the tool holder 17 from the spindle 9 from oscillating due to the superposition of the torque of the spindle motor 54 in the ON state, so that no load is applied to the mechanical mechanism. The mechanical mechanism includes a draw bar 81, a rod member 60, a tension coil spring, and the like. The spindle head 7 arrives at the ATC origin. The third step 103 is a step of rotating the tool magazine 21 . The tool changer 20 positions the next tool designated by the control command of the NC program at the tool change position. The tool replacement position is the lowermost position of the tool magazine 21 and a position close to and facing the main shaft 9 . The next tool positioned at the tool change position is located below the spindle head 7 moved to the ATC origin. As shown in the order of FIG. 7 and FIG. 6 , the fourth process 104 is to lower the spindle head 7 from the ATC origin toward the Z-axis origin so that the tapered mounting portion 17A of the tool holder 17 enters the tapered hole of the spindle 9 18 processes. With the tapered mounting portion 17A of the tool holder 17 inserted into the tapered hole 18 of the spindle 9 , the spindle head 7 further descends. The plate cam body 66 provided on the lever member 60 slides toward the cam follower 67 . The cam follower 67 slides along the cam shape of the plate cam body 66 . As shown in FIG. 5 , the lever member 60 rotates clockwise around the support shaft 61 when viewed from the right side. Therefore, the horizontal bar 62 is separated from the pin 58, and the downward pressing on the draw bar 81 is released. The draw bar 81 releases the downward bias on the holder holding member 19 , and the holder holding member 19 holds the draw bolt 17B. The spindle head 7 further descends to reach the Z-axis origin. The fifth step 105 is a step in which the spindle head 7 descends from the Z-axis origin toward the target position. When the cutting feed is performed next to the end of the tool changing operation, the numerical controller 30 starts the rotation of the spindle motor 54 before the spindle head 7 reaches the target position. The spindle head 7 reaches the target position, and the tool replacement operation ends. After the spindle head 7 reaches the target position and the spindle speed reaches the target value, the numerical control device 30 executes the cutting feed. The first process 101 and the second process 102 are ascending processes, and the fourth process 104 and the fifth process 105 are descending processes.

The electrical configurations of the numerical controller 30 and the machine tool 1 will be described with reference to FIG. 8 . The numerical controller 30 includes a CPU 31 , a ROM 32 , a RAM 33 , a storage device 34 , an input/output unit 50 , motor control units 35 to 39 , and the like. The CPU 31 collectively controls the numerical controller 30 . The ROM 32 stores various programs and the like. The ROM 32 stores a movement control program for the CPU 31 to execute movement control processing (see FIGS. 12 and 13 ), which will be described later. The CPU 31 functions as an example of a processing device that executes the movement control unit by decompressing the movement control program stored in the ROM 32 on the RAM 33 . The RAM 33 temporarily stores various data during execution of various processes. The storage device 34 is, for example, a nonvolatile flash memory, and stores, for example, a plurality of NC programs input and registered by an operator through the input unit 24 . The NC program is composed of a plurality of blocks including various control commands, and controls various operations including axis movement and tool replacement of the machine tool 1 in block units. Axis movement refers to an operation to move the position of the main axis. The number of internal commands generated by the control unit by interpreting one control command differs depending on the type of control command. The internal command refers to a command for specifically controlling the operation of the device by interpreting the control command of the NC program. In this embodiment, the command for instructing the movement of the axis among the internal commands is referred to as a movement command, such as a fast-forward command, a cutting feed command, and other movement commands. "The internal command for the next operation includes a spindle rotation command to rotate the spindle" includes, for example, a spindle rotation command included in a part of the internal commands, or a case where the internal command itself is a spindle rotation command. 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, for example, servo motors. The motor control unit 35 is connected to the X-axis motor 51 and the encoder 51B. The motor control unit 36 is connected to the Y-axis motor 52 and the encoder 52B. The motor control unit 37 is connected to the Z-axis motor 53 and the encoder 53B. The motor control unit 38 is connected to the spindle motor 54 and the encoder 54B. The motor control unit 39 is connected to the magazine motor 55 and the encoder 55B. The motor control units 35 to 39 receive internal commands from the CPU 31 and output drive currents to the corresponding motors 51 to 55 . Motor control units 35 to 39 receive feedback signals from encoders 51B to 55B, and perform feedback control of position and speed. The feedback signal is a pulse signal. In the following description, when the motor control units 35 to 39 are collectively referred to as the motor control unit 40 . The motor control unit 40 each includes a distribution processing unit 401 and a filter processing unit 402 which will be described later. The input/output unit 50 is connected to the input unit 24 and the display unit 25 . The user can select one NC program from a plurality of NC programs through the input unit 24 . The CPU 31 displays the selected NC program on the display unit 25 . The CPU 31 controls the operation of the machine tool 1 based on the NC program displayed on the display unit 25 .

The acceleration and deceleration processing of the moving speed will be described with reference to FIG. 9 . The CPU 31 interprets the NC program for each block, and generates internal commands for the X-axis, Y-axis, and Z-axis. When generating a movement command as one of the internal commands, the motor control unit 40 receives the movement command from the CPU 31 . The motor control unit 40 calculates a target position, a moving distance, a moving speed, a moving time, and the like for each axis based on the received moving command. The numerical controller 30 performs acceleration and deceleration processing. The acceleration/deceleration process is a process of smoothing the speed change with respect to the calculated moving speed for each axis through a moving average filter (hereinafter referred to as an FIR filter). The acceleration and deceleration time constant of the FIR filter (hereinafter referred to as the time constant) corresponds to the number of samples averaged by the FIR filter. For example, when the sampling time is 1 msec and the time constant of the FIR filter is 10 msec, the FIR filter uses the average of the commands up to the previous 10 commands including the current movement command as the current output. The time constant of the FIR filter is t ₁ . The motor control unit 40 distributes the moving speeds every 1 msec from t11 , processes them with an FIR filter, and outputs them to the axes of the X-axis motor 51 , Y-axis motor 52 , and Z-axis motor 53 . The tool takes time _t1 from t11 to increase the speed gently and then reaches the maximum speed at t12. The tool moves at the highest speed, and at the same time as the assignment of the moving speed at t13 is completed, the speed of the tool gradually decreases from the highest speed over time _t1 , and stops at t14. Therefore, the numerical controller 30 absorbs a sudden change in the moving speed by processing the moving speed with an FIR filter, thereby suppressing the vibration of the machine tool 1 . In addition to the movement command, the internal command includes a command such as a spindle rotation command of M03 that does not involve movement of the workpiece or the spindle head 7 .

A basic operation pattern in which the spindle motor 54 is turned on first will be described with reference to FIG. 10 . The command to turn on the spindle motor 54 is a command to turn on the power to the spindle motor 54 . When the spindle rotation command is executed from the energized OFF state of the spindle motor 54 , the rotation start of the spindle 9 is delayed by the time required from the output of the ON command of the spindle motor 54 to the energized ON state. For example, in this embodiment, a movement command is assumed in which the spindle motor 54 is off, the current operation (hereinafter referred to as the current operation) is fast forward, and the next operation includes a spindle rotation command. The upper graph in FIG. 10 shows a conventional basic operation pattern. The speed block B2, which is the fast-forward command of the current action, begins to distribute the moving speed according to the sampling period from t20, and uses the FIR filter to perform acceleration and deceleration processing. Thus, the tool accelerates smoothly from t20 onwards and reaches its maximum speed at t21. Simultaneously with the completion of the allocation of the moving speed at t22, the vehicle decelerates gradually from the highest speed, and stops after reaching the target position at t23. The conventional numerical controller outputs an ON command for the spindle motor 54 at t23 when the target position of the fast forward command is reached. At t24 when the spindle motor 54 is turned on, the spindle 9 can start to rotate, and at t26 the movement as the next operation is completed. A typical fast-forward command is G00, which is a command for positioning at the highest positioning speed stored in the storage device 34 . The lower graph in FIG. 10 shows the basic operation pattern of this embodiment. The numerical controller 30 of the present embodiment outputs an ON command for the spindle motor 54 at t22 when the assignment of the moving speed of the fast forward command is completed. At t22 when the distribution of the moving speed is completed, the numerical controller 30 determines whether the internal command for the next operation is a movement command including a spindle rotation command. By executing the ON command of the spindle motor 54 at t22, at t23 at which the target position of the fast-forward command is reached, the spindle motor 54 has been brought into the ON state. Therefore, the main shaft 9 can be rotated immediately at t23, so that the numerical control device 30 can shorten the machining cycle compared with conventional ones.

The target operation pattern of this embodiment will be described with reference to FIG. 11 . The target operation patterns A to G are operation patterns based on movement commands generated by interpreting the NC program, and define at least the current operation and the next operation. When the next action is the Nth action, the current action is the N-1th action. The spindle motors 54 are all in the off state when the current operation starts. When the numerical controller 30 does not rotate the spindle 9 , in principle, by turning off the energization of the spindle motor 54 , the power consumed for driving the spindle motor 54 can be saved.

The N-1th action of modes A to F is fast forward. The Nth action of mode A is cutting feed and spindle rotation. The Nth action of mode B is tapping. The Nth action in mode C is fast forward and spindle rotation, and the N+1th action is cutting feed. The Nth action of mode D is fast forward and spindle rotation, the N+1th action is fast forward, and the N+2th action is cutting feed. The Nth action in mode E is spindle rotation, and the N+1th action is cutting feed. The Nth action of mode F is spindle rotation, the N+1st action is fast forward, and the N+2th action is cutting feed. The N-1th action of mode G is the descending action from the ATC origin in the tool changing action, the Nth action is the descending action from the Z-axis origin and the spindle rotation in the tool changing action, and the N+1th action The action is cutting feed. Regarding the cutting feed command (cutting feed command), the feed speed is usually described in the program, but in this embodiment, the highest cutting feed speed stored in advance in the storage device 34 is used.

Movement control processing will be described with reference to FIGS. 12 and 13 . When the user selects an NC program using the operation panel 15 and inputs an execution operation, the CPU 31 reads the movement control program from the ROM 32 and executes this process.

An example of the NC program P1 of pattern A is shown.

As shown in FIG. 12, the CPU 31 reads the NC program P1 of one block (S1). The CPU 31 judges whether or not there is an end command of M30 in one read block (S2). There is no M30 in the read-in block (S2: No), so the CPU 31 interprets G00 as a control command in the read-in block to generate an internal command (S3), and the generated internal command It is output to the motor control unit 40 (S4). G00 is a fast-forward command, so the CPU 31 generates a fast-forward movement command as an internal command. The CPU 31 judges whether the spindle motor 54 is off and whether the X-axis, Y-axis, and Z-axis are currently moving (S5). The spindle motor 54 is off, but the X-axis, Y-axis, and Z-axis are not currently moving (S5: No), so the CPU 31 judges whether the received internal command is the first moving command (S20). The first movement command refers to the first movement command generated by interpreting the NC program. Since the executed internal command is the first movement command (S20: YES), the allocation processing unit 401 of the motor control unit 40 starts the movement allocation of the speed block B3 (see FIG. 14 ) which is a fast-forward movement command (S17).

As shown in FIG. 14 , at t30 , the allocation processing unit 401 of the motor control unit 40 starts the movement allocation of the speed block B3 in each sampling cycle. The filter processing unit 402 of the motor control unit 40 performs acceleration and deceleration processing of the moving speed for each axis using an FIR filter, and outputs drive currents to the motors 51 to 53 . The tool 4 thus accelerates smoothly from t30 onwards, reaching its maximum speed at t31. The CPU 31 judges whether the movement assignment of the speed block B3 has been completed (S18). While the movement allocation is not completed (S18: No), the CPU 31 returns to S18 and waits. When the movement allocation of the velocity block B3 is completed at t32 (S18: Yes), the CPU 31 judges that all movement commands in one block have been completed (S19: Yes), and reads the second line of the NC program P1 (S1). There is no M30 in one block of the read second line (S2: No), so the read second line is interpreted to generate an internal command (S3), and the internal command is output to the motor control unit 40 ( S4). G01 on the second line is a cutting feed command including a spindle rotation command. The current state is that the spindle motor 54 is off and moving (S5: YES), so the CPU 31 judges whether the internal command includes a spindle rotation command (S6). Since the internal command includes a spindle rotation command (S6: YES), the CPU 31 judges whether or not the internal command is descending from the Z-axis origin during the tool change operation (S7). Since the internal command is not descending from the Z-axis origin (S7: No), the CPU 31 outputs an ON command to the spindle motor 54 at t32 when the movement allocation of the speed block B3 is completed (S10). The tool decelerates gradually from t32 onwards. Before the tool stops at the target position at t33, the spindle motor 54 is turned on. The CPU 31 judges whether or not the current coordinates of the tool have reached the target position (S11). While the current coordinates have not reached the target position (S11: No), the CPU 31 returns to S11 and waits. When the current coordinate reaches the target position at t33 (S11: YES), the CPU 31 instructs the spindle motor 54 to rotate (S12). The spindle motor 54 starts to rotate. While the current coordinates do not reach the target position, the spindle motor 54 does not rotate, and therefore the numerical controller 30 prevents the spindle 9 from rotating through the current operation that does not include a spindle rotation command. The CPU 31 judges whether or not the current operation is descending from the Z-axis origin during the tool replacement operation (S13). The current operation is not descending from the Z-axis origin (S13: No), so the CPU 31 judges whether the next operation is a tapping operation (S14). The next operation is cutting feed (S14: No), so the CPU 31 judges whether the next operation is fast forward (S15). The next operation is cutting feed (S15: No), so the CPU 31 judges whether or not the spindle rotation speed has reached the target value (S16). The target value may be determined, for example, as a ratio (P%) to the spindle speed (S command value). For example, in the case of P=85(%), it is considered that the spindle speed reaches the target value at 8500 (rpm) relative to the S command value of 10000 (rpm). When the spindle rotation speed has not reached the target value (S16: No), the CPU 31 returns to S16 and waits. When the spindle speed reaches the target value at t34 (S16: Yes), the motor control unit 40 starts the movement distribution of the speed block B4 of the cutting feed command (S17), and outputs it to each motor 51-53 after processing by the FIR filter. . Therefore, the tool speed increases gradually from t34 to reach the highest speed at t35. At t36, when the movement allocation of the speed block B4 is completed (S18: Yes), all the movement instructions in one block are completed (S19: Yes), so the CPU 31 returns to S1 in FIG. 12 and repeats the process. When M30 exists in one read block (S2: YES), the CPU 31 ends this process.

As described above, in the mode A, the numerical controller 30 outputs the ON command of the spindle motor 54 before t33 when the current operation is completed. Therefore, the time required for the spindle motor 54 to be energized and turned on can be shortened, and thus the waiting time W1 from t33 to t34 can be shortened.

NC program P2 of mode B is shown.

As shown in FIG. 12, the CPU 31 reads the NC program P2 of one block (S1). The first line of the NC program P2 is the same as the first line of the NC program P1 of the mode A, and therefore descriptions of the same parts are simplified or omitted. As shown in FIG. 15 , at t40 , the allocation processing unit 401 of the motor control unit 40 starts the movement allocation of the speed block B5 for the fast-forward command in each sampling period ( S17 ). The filter processing unit 402 of the motor control unit 40 performs acceleration and deceleration processing of the moving speed for each axis using an FIR filter, and outputs drive currents to the motors 51 to 53 . The tool 4 thus accelerates smoothly from t40 onwards and reaches its maximum speed. When the movement allocation of the speed block B5 is completed at t41 (S18: YES), all movement instructions in one block are completed (S19: Yes), so the CPU 31 reads the second line of the NC program P2 (S1). The second line is a tapping command of G77, which is not M30 (S2: No), so the CPU 31 interprets the read G77 of the second line to generate four internal commands (S3). As shown in FIG. 16 , the tapping operation includes, for example, four operations of a fast-forwarding operation 151 , a tapping operation 152 , a tapping operation 153 , and a fast-forwarding operation 154 . The fast-forward operation 151 is, for example, an operation for moving the main shaft 9 from the Z100 to the reference point (point R) of the Z40 in a fast-forward manner without rotating the spindle 9 . The tapping operation 152 is an operation of performing tapping by rotating the spindle 9 in one direction from the point R and moving to the bottom of the hole at Z20. The tapping operation 153 is an operation in which the main shaft 9 is rotated in the reverse direction and moved back from the hole bottom to the point R, and is a tapping retraction operation. The fast-forward operation 154 is an operation for moving the main shaft 9 in a fast-forward manner from point R to retracting to Z100 without rotating the main shaft 9 . Therefore, the CPU 31 generates four movement instructions (two fast-forward instructions and two tapping instructions) corresponding to the fast-forward operation 151, the tapping operation 152, the tapping operation 153, and the fast-forward operation 154 based on G77 in one block. . The movement commands corresponding to the tapping operations 152 and 153 all need to rotate the main shaft 9, and therefore include a main shaft rotation command. The fast-forward command corresponding to the fast-forward action 154 includes a spindle stop command. I2 in the tapping command of G77 means that the tapping pitch is 2. The CPU 31 generates a fast-forward command as an internal command corresponding to the fast-forward operation 151, and outputs it to the motor control unit 40 (S4). At t41, the spindle motor 54 is off and moving (S5: YES). The fast forward command does not include the spindle rotation command (S6: No), nor is it the first movement command (S20: No). The CPU 31 judges whether the current coordinates of the tool currently moving have reached the target position (Z100) (S21). While the current coordinates have not reached the target position (S21: No), the CPU 31 returns to S21 and waits. When the current coordinate reaches the target position at t42 (S21: YES), the CPU 31 judges whether or not the next operation is a tapping retracting operation (S22). The next operation is not a tapping retracting operation (S22: No), so the CPU 31 judges whether the spindle 9 is rotating (S23). The main shaft 9 is not rotating (S23: No), so the motor control unit 40 starts to distribute the movement of the speed block B6 of the tapping command (S17), uses the FIR filter to perform acceleration and deceleration processing of the movement speed, and outputs to the Z-axis motor 53 drive current. Therefore, the tool 4 gradually accelerates from t42 and then performs the fast-forward operation 151 after reaching the maximum speed. When the movement assignment of the speed block B6 is completed at t43 (S18: YES), the CPU 31 judges whether all internal instructions within a block have been completed (S19). Three of the four internal commands generated by interpreting G77 remain (S19: No), so the CPU 31 outputs a tapping command corresponding to the tapping operation 152 to the motor control unit 40 (S4). At t43, the spindle motor 54 is off and moving (S5: YES). The thread tapping instruction includes the spindle rotation instruction (S6: Yes), but the thread tapping instruction is not descending from the Z-axis origin (S7: No), so the CPU 31 outputs the connection of the spindle motor 54 at t43 when the movement distribution of the speed block B6 is completed. instruction (S10). The tool 4 decelerates gradually from t43 onwards. Before the tool 4 stops at point R which is the target position at t44, the spindle motor 54 is turned on. The CPU 31 judges whether or not the current coordinates of the tool have reached the R point (S11). When the current coordinate reaches point R at t44 (S11: YES), the CPU 31 outputs a rotation command to the spindle motor 54 (S12). The spindle motor 54 starts to rotate. The CPU 31 judges whether or not the current operation is descending from the Z-axis origin during the tool replacement operation (S13). The current operation is not descending from the Z-axis origin (S13: No), so the CPU 31 judges whether the next operation is a tapping operation (S14). Since the next operation is a tapping operation (S14: YES), the motor control unit 40 starts the movement distribution of the speed block B7 of the tapping command (S17). The motor control unit 40 performs acceleration and deceleration processing of the moving speed using an FIR filter, and outputs a drive current to the Z-axis motor 53 . Therefore, the tool 4 rotates from t44 and accelerates gently to perform the tapping operation. When the movement assignment of the speed block B7 is completed at t45 (S18: YES), the CPU 31 judges whether all internal instructions within a block have been completed (S19). Two of the four internal commands generated by interpreting G77 remain (S19: No), so the CPU 31 outputs an internal command corresponding to the tapping operation 153 to the motor control unit 40 (S4). At t45, the spindle motor 54 is turned on (S5: No), and the internal command is not the first movement command (S20: No), so the CPU 31 judges whether the current coordinate of the tool 4 has reached Z20 (S21). Z20 is the target position of the tapping operation 152 . When the current coordinate reaches the target position at t46 (S21: YES), the CPU 31 judges whether or not the next operation is a tapping retracting operation (S22). The tapping operation 153 that is the next operation is a tapping retraction operation (S22: Yes), so the CPU 31 temporarily stops the spindle motor 54 in the ON state and then rotates it in the reverse direction, and starts the operation corresponding to the tapping operation 153. Movement allocation of the speed block of the tapping instruction (S17). The motor control unit 40 performs acceleration and deceleration processing of the moving speed using an FIR filter, and outputs a drive current to the Z-axis motor 53 . Therefore, the cutter 4 reversely rotates from t46, moves upward while gradually accelerating, and gradually retreats upward from the hole obtained by tapping. When the movement allocation of the speed block of the tapping operation 153 is completed (S18: YES), the CPU 31 judges whether all internal commands in one block have been completed (S19). One of the four movement commands generated by interpreting G77 remains (S19: No), so the CPU 31 outputs a fast-forward command corresponding to the fast-forward operation 154 to the motor control unit 40 (S4). Since the spindle motor 54 is on (S5: NO), the CPU 31 judges whether the fast forward command is the first movement command (S20). The fast-forward command is not the first movement command (S20: NO), so the CPU 31 judges whether or not the R point has been reached (Z40) (S21). Point R is the target position of the tapping operation 153 . When the tool 4 reaches the R point (S21: YES), it withdraws upward from the hole obtained by performing the tapping process. The next operation is not a tapping retraction operation (S22: No), so the CPU 31 judges whether the main shaft 9 is rotating (S23). The spindle 9 is rotating (S23: YES), so the CPU 31 judges whether or not a spindle stop command is included in the received fast-forward command (S24). The fast-forward command corresponding to the fast-forward operation 154 includes a spindle stop command (S24: YES), so the CPU 31 outputs a command to turn off the spindle motor 54 (S25). Therefore, the rotation of the main shaft 9 stops. The motor control unit 40 starts the movement distribution of the speed block of the fast forward command (S17). The motor control unit 40 performs acceleration and deceleration processing of the moving speed using an FIR filter, and outputs a drive current to the Z-axis motor 53 . Therefore, the cutter 4 moves upward while gradually increasing the speed from the R point. When the movement allocation of the speed block of the fast-forward action 154 is completed (S18: Yes), all movement instructions in one block are completed (S19: Yes), so the CPU 31 reads in the next block (S1). When the fast forward action 154 is completed, the tool 4 returns to the Z100 position. When M30 exists in one read block (S2: YES), the CPU 31 ends this process.

As described above, in the mode B, the numerical controller 30 outputs the ON command of the spindle motor 54 before t44 when the fast-forward operation 151 as the current operation is completed. Therefore, the numerical control device 30 can shorten the time required for the spindle motor 54 to be energized, so that the tapping operation as the next operation can be quickly started after t44 when the fast-forward operation 151 is completed.

An example of the NC program P3 of pattern C is shown.

The CPU 31 reads the NC program P3 of one block (S1). The first line of NC program P3 is the same as the first line of NC program P1 in mode A, which is G00. As shown in FIG. 17 , at t50 , the motor control unit 40 starts assignment of movement of the speed block B8 for the fast-forward command in each sampling cycle ( S17 ). The motor control unit 40 performs acceleration and deceleration processing of the moving speed for each axis using an FIR filter, and outputs drive currents to the respective motors 51 to 53 . The tool therefore accelerates smoothly from t50 onwards to its maximum speed. When the movement assignment is completed at t51 (S18: YES), all movement instructions in one block have been completed (S19: YES), so the CPU 31 reads the second line of the NC program P2 (S1). The second line is the fast forward command of G00 and the spindle rotation command of M03 (S2: No). Therefore, the CPU 31 generates a fast-forward command including a spindle rotation command as an internal command ( S3 ). The CPU 31 outputs a fast-forward command to the motor control unit 40 (S4). At t51, the spindle motor 54 is off and moving (S5: YES). The outputted fast-forward command includes the spindle rotation command (S6: yes), but it does not descend from the Z-axis origin (S7: no), so the CPU 31 outputs the connection of the spindle motor 54 at t51 when the movement distribution of the speed block B8 is completed. instruction (S10). The tool 4 decelerates gradually from t51 onwards. Before the tool 4 stops at the target position at t52, the spindle motor 54 is turned on. The motor control unit 40 judges whether or not the current coordinates of the tool 4 have reached the target position (S11). When the current coordinates of the tool 4 have reached the target position at t52 (S11: YES), the CPU 31 instructs the rotation of the spindle motor 54 (S12). The spindle motor 54 starts to rotate. The current action is not descending from the Z-axis origin (S13: No), and the next action is not a tapping action (S14: No), so the CPU 31 judges whether the movement command of the next action is a fast forward command (S15). Since the movement command of the next operation is a fast-forward command (S15: YES), at t52 the motor control unit 40 starts the movement allocation of the speed block B9 for the fast-forward command (S17). The motor control unit 40 performs acceleration and deceleration processing of the moving speed for each axis using an FIR filter, and outputs drive currents to the respective motors 51 to 53 . The tool 4 therefore accelerates smoothly from t52 onwards and reaches its maximum speed. When the move allocation is completed at t53 (S18: YES), all the move instructions in one block have been completed (S19: YES), so the CPU 31 reads the third line of the NC program P2 (S1). The third line is the cutting feed command of G01 (S2: No). Therefore, the CPU 31 generates a cutting feed command as an internal command (S3). The CPU 31 outputs a cutting feed command to the motor control unit 40 (S4). At t53, the spindle motor 54 is turned on and is moving (S5: NO). The CPU 31 judges whether the fast forward command is the first movement command (S20). Since the fast forward command is not the first movement command (S20: No), the CPU 31 judges whether or not the tool 4 has reached the target position of the fast forward command (S21). When the current coordinates at t54 have reached the target position (S21: Yes), the next action is not a tapping thread retraction action (S22: No), and the current spindle 9 is rotating (S23: Yes), so the CPU 31 judges that the cutting feed is in progress. Whether the command includes the spindle stop command (S24). The cutting feed command does not include a spindle stop command (S24: No), so the CPU 31 judges whether or not the next operation is fast forward (S26). The next operation is cutting feed (S26: No), so the CPU 31 judges whether or not the spindle rotation speed has reached the target value (S27). When the spindle rotation speed reaches the target value at t55 (S27: YES), the motor control unit 40 starts the movement distribution of the speed block B10 of the cutting feed command (S17). The motor control unit 40 performs acceleration and deceleration processing of the moving speed for each axis using an FIR filter, and outputs drive currents to the respective motors 51 to 53 . Tool 4 therefore accelerates smoothly from t55 onwards and reaches its maximum speed. When at t56 the movement allocation of the speed block B10 is completed (S18: YES), all internal commands in one block are completed (S19: YES), so the CPU 31 reads the next block of the NC program P3 (S1). At t57 the tool 4 reaches the target position of the cutting feed. When M30 exists in one read block (S2: YES), the CPU 31 ends this process.

As described above, in the mode C, the numerical controller 30 outputs an ON command for the spindle motor 54 before t52 when the current operation is completed. Therefore, the numerical controller 30 can shorten the time required to turn on the spindle motor 54 , and therefore can quickly rotate the spindle 9 after t52 when the current operation is completed. During the fast forward of the next action, the spindle speed increases. The numerical controller 30 performs the cutting feed after the spindle speed reaches the target value after the next operation is completed, so the period between t54 and t55 is the waiting time W2. Mode C can shorten the waiting time W2 by the time it takes for the spindle motor 54 to be turned on.

An example of the NC program P4 of the pattern D is shown.

The first row and the second row of pattern D are the same as those of pattern C, so the description of the same parts as pattern C will be omitted in this embodiment, and the differences from pattern C will be described using FIG. 18 Describe the center. The speed block B11 corresponds to the fast forward command of G00 in the first line. The tool 4 starts moving at t60 and reaches the target position at t62. The speed block B12 corresponds to the fast forward command of G00 and the spindle rotation command of M03 in the second line. The tool 4 starts to rotate and starts to move at t62. When the tool reaches the target position at t63 (S21: YES), the CPU 31 judges whether the next motion is a tapping retracting motion (S22). The speed block B13 corresponds to the fast forward command of G00 in the third line. The next action is fast forward, the main shaft 9 is currently rotating, and the next action does not include a main shaft stop command (S22: No, S23: Yes, S24: No, S26: Yes), so the CPU 31 causes the motor control section 40 to start at t63. The movement distribution of the speed block B13 of the fast forward command is performed (S17). At t63, the spindle speed did not reach the target value, but continued to increase towards the target value. Tool 4 reaches the target position at t64. The speed block B14 corresponds to the cutting feed command of G01 in the fourth line. At t64 when the fast-forward action (N+1th action) in the third row ends, the spindle speed does not reach the target value. Therefore, the tool 4 does not start moving the speed block B14 while the spindle rotation speed has not reached the target value. At t65, the spindle speed reaches the target value. Therefore, the tool 4 cuts the workpiece by starting to rotate at t65 and starting to move, and reaches the target position at t66. In pattern D, the period between t64 and t65 becomes the waiting time W3. The movement assignment of speed block B11 starts at t60 and finishes at t61. The next action is fast forward including the spindle rotation command. Therefore, the CPU 31 outputs an ON command of the spindle motor 54 at t61. The spindle motor 54 is turned on until t62 when the tool reaches the target position by the fast-forward of the current operation. Therefore, the numerical controller 30 can shorten the time required to turn on the spindle motor 54 , and therefore can quickly rotate the spindle 9 after t62 when the current operation is completed. Therefore, the numerical controller 30 can shorten the waiting time W3 by the time it takes for the spindle motor 54 to be turned on.

An example of the NC program P5 of the pattern E is shown.

The movement command generated by interpreting the first line of NC program P5 is the fast forward command of G00, the internal command generated by interpreting the second line is the spindle rotation command of M03, and the movement command generated by interpreting the third line The command is the cutting feed command of G01. In mode E, the action in the first line is the current action. The second line is only the spindle rotation command, and the third line is the cutting feed command, so the cutting feed obtained by combining the second line and the third line becomes the next action. Therefore, pattern E behaves the same as pattern A shown in FIG. 14 . Also in the mode E, the numerical controller 30 outputs an ON command for the spindle motor 54 before t33 when the fast forwarding of the current operation is completed. Therefore, the numerical controller 30 can shorten the time taken to turn on the spindle motor 54 , and thus can shorten the waiting time W1 until the next operation starts.

An example of the NC program P6 of pattern F is shown.

The movement command generated by interpreting the first line of NC program P6 is the fast forward command of G00, the internal command generated by interpreting the second line is the spindle rotation command of M03, and the movement command generated by interpreting the third line The command is the fast forward command of G00, and the movement command generated by explaining the fourth line is the cutting feed command of G01. In mode F, the action on the first line is also the current action. The second line is only the spindle rotation command, and the third line is the fast forward command, so the fast forward action obtained by combining the second line and the third line becomes the next action. Therefore, pattern F behaves the same as pattern C shown in FIG. 15 . Also in the mode F, the numerical controller 30 outputs an ON command for the spindle motor 54 before t44 when the fast-forwarding of the current operation is completed. Therefore, the numerical controller 30 can shorten the time required to turn on the spindle motor 54 , and therefore can quickly rotate the spindle 9 after t44 when the current operation is completed.

An example of the NC program P7 of the mode G is shown and described using FIG. 19 .

G100 in the first line of NC program P7 is a tool replacement command. The tool replacement operation is as described above. As shown in FIG. 3 , in the present embodiment, the designated position Ps is set on the Z axis in the fourth step 104 . The numerical controller 30 rotates the spindle 9 in the fifth step 105 . In order to quickly rotate the spindle 9 in the fifth step 105 , the numerical controller 30 preempts the ON command of the spindle motor 54 in the fourth step 104 . In the fourth step 104 , the tool holder 17 is attached to the tapered hole 18 of the main shaft 9 from below the tapered hole 18 . Before the tool holder 17 is mounted on the spindle 9, the spindle motor 54 is switched on. There is a possibility that the torque of the spindle motor 54 for driving the spindle 9 is superimposed on the above-mentioned mechanical mechanism to cause an influence such as oscillation. Therefore, it is preferable that the numerical controller 30 outputs an ON command for the spindle motor 54 after the tool holder 17 is attached to the spindle 9 . The specified position Ps set in the fourth step 104 is a position where the spindle motor 54 can be turned on. The specified position Ps is, for example, a parameter that can be freely set using the operation panel 15, and may be stored in the storage device 34 or the like, for example.

As shown in FIG. 12, the CPU 31 reads the NC program P7 of one block (S1). Since M30 does not exist in one read block (S2: No), the CPU 31 interprets G100 in one read block to generate five internal commands (S3). The five internal commands are the first fast-forward command corresponding to the first process 101, the second fast-forward command and the spindle stop command corresponding to the second process 102, the tool magazine rotation command corresponding to the third process 103, and the fourth The third fast-forward command corresponding to the process 104 and the fourth fast-forward command and spindle rotation command corresponding to the fifth process 105 . Among the generated internal commands, the first to fourth fast forward commands are movement commands. The generated internal commands are stored in RAM 33 . The CPU 31 outputs the first fast-forward command to the motor control unit 40 (S4). The spindle motor 54 is off, but the tool 4 has stopped (S5: No), so the CPU 31 judges whether the first fast-forward command is the first movement command (S20). Since the first fast-forward command is the first movement command (S20: YES), the motor control unit 40 starts the movement allocation of the speed block of the first fast-forward command (S17). When the movement allocation is completed (S18: Yes), there is an incomplete movement command in one block (S19: No), so the CPU 31 outputs the second fast forward command and the spindle stop command to the motor control unit 40 (S4). The spindle motor 54 is off and moving, and the second fast forward command does not include a rotation command (S5: Yes, S6: No), so the CPU 31 determines whether the second fast forward command is the first move command (S20). Since the second fast forward command is not the first movement command (S20: No), the CPU 31 determines whether the spindle head 7 has reached the Z-axis origin which is the target position of the first process 101 (S21). When the spindle head 7 has reached the Z-axis origin (S21: Yes), the next action is not a tapping retraction action (S22: No), and the main shaft 9 is in a disconnected state (S22: No), so the motor control unit 40 starts Movement allocation of the second fast forward instruction (S17). The spindle head 7 starts to move from the origin of the Z axis towards the origin of the ATC. When the movement allocation is completed (S18: Yes), there is an internal command not completed within one block (S19: No), so the CPU 31 outputs the third fast-forward command to the motor control unit 40 (S4). The current spindle motor 54 is in an off state and the spindle head 7 is moving (S5: Yes), but the third fast-forward command does not include a spindle rotation command (S6: No), so the CPU 31 judges whether the third fast-forward command is The first movement instruction (S20). Since the third fast forward command is not the first movement command (S20: No), the CPU 31 determines whether the spindle head 7 has reached the ATC origin which is the target position of the second process 102 (S21). When the spindle head 7 reaches the ATC origin (S21: Yes), the next action is not a tapping retreat action (S22: No), and the main shaft 9 does not rotate (S23: No). Therefore, after the rotation operation of the tool magazine base 71 as the third step 103 is completed, the motor control unit 40 starts the movement distribution of the speed block B15 of the third fast forward command at t70 ( S17 ). The spindle head 7 starts to descend from the ATC origin toward the Z-axis origin. When the movement allocation of the speed block B15 at t71 is completed (S18: Yes), there is an internal instruction not completed in one block (S19: No), so the CPU 31 outputs the fourth fast-forward instruction to the motor control section 40 (S4 ). The current spindle motor 54 is in an off state and the spindle head 7 is moving (S5: Yes), and the fourth fast-forward command includes a spindle rotation command (S6: Yes), so the CPU 31 judges whether the fourth fast-forward command is from Z The axis origin is lowered (S7). The fourth fast-forward command is descending from the Z-axis origin (S7: YES), so the motor control unit 40 starts the movement distribution of the speed block B16 for the fourth fast-forward command (S8). The speed block B16 is a speed block for moving the spindle head 7 at a low speed until reaching the Z-axis origin at t72 and then moving at a high speed from the Z-axis origin. Therefore, the moving speed is fixed between t71 and t72 when the speed of the speed block B15 is gradually decelerated from t71 and the speed of the speed block B16 is gradually accelerated.

The CPU 31 judges whether or not the current coordinates of the spindle head 7 are equal to or less than the designated position Ps (S9). When the current coordinates are higher than the designated position Ps (S9: NO), the CPU 31 returns to S9 to stand by. When the current coordinate at t711 becomes below the designated position Ps (S9: YES), the tool holder 17 is already attached to the spindle 9, so the CPU 31 outputs a command to turn on the spindle motor 54 (S10). Therefore, the numerical control device 30 prevents the mechanical mechanism for attaching and fixing the tool holder 17 to the spindle 9 from oscillating due to superposition of the torque of the spindle motor 54 in the ON state, and thus does not apply a load to the mechanical mechanism.

The CPU 31 judges whether or not the spindle head 7 has reached the Z-axis origin which is the target position in the fourth step 104 (S11). While the Z-axis origin is not reached (S11: No), the CPU 31 returns to S11 and waits. When the Z-axis origin is reached at t72 (S11: YES), the CPU 31 instructs the spindle motor 54 to rotate (S12). The ongoing operation is the fifth process 105 and descending from the Z-axis origin (S13: Yes), so the CPU 31 judges whether the movement allocation of the speed block B16 of the fourth fast-forward command has been completed (S18). When the movement assignment of the speed block B16 at t73 is completed (S18: Yes), all internal instructions in one block have been completed (S19: Yes), so the CPU 31 returns to S1 and reads the block of the second line of the NC program P7. The second row is a cutting feed command of G01, which is not M30 (S2: No), so the CPU 31 interprets the read G01 of the second row, and generates a cutting feed command as an internal command (S3). The CPU 31 outputs a cutting feed command to the motor control unit 40 (S4). The spindle head 7 is moving, but the spindle motor 54 is already on (S5: NO), so the CPU 31 judges whether the cutting feed command is the first movement command (S20). Since the cutting feed command is not the first movement command (S20: No), the CPU 31 determines whether the spindle head 7 has reached the target position (Z20) of the fifth step 105 (S21). When the target position is reached (S21: Yes), the cutting feed as the next action is not a tapping retraction action (S22: No), the spindle 9 is rotating (S23: Yes), and the cutting feed command does not include the spindle The command is stopped (S24: NO), so the CPU 31 judges whether the next action is fast forward (S26). The next operation is the cutting feed operation (S26: No), so the CPU 31 judges whether or not the spindle rotation speed is equal to or greater than the target value (S27). When the spindle rotation speed is smaller than the target value (S27: NO), the CPU 31 returns to S27 and waits. Therefore, while the spindle speed is lower than the target value, the spindle head 7 stops. When the spindle rotation speed becomes equal to or greater than the target value at t75 (S27: YES), the motor control unit 40 starts the movement distribution of the speed block B17 of the cutting feed command (S17). In pattern G, the period between t74 and t75 becomes the waiting time W4. Since the spindle head 7 starts moving toward the target position, the tool 4 rotates to cut the workpiece. When the movement distribution of the speed block B17 was completed (S18: yes), all movement instructions in a block of the second line of the NC program P7 had been completed (S19: yes), so the CPU31 read into the next block of the NC program P7 ( S1). When the next block to be read is M30 (S2: YES), the numerical controller 30 ends this process. The spindle head 7 ends the cutting feed operation at t76.

As described above, in mode G, the numerical controller 30 outputs an ON command for the spindle motor 54 before t72 when the current operation of descending from the ATC origin toward the Z-axis origin in the descending step of the tool replacement operation is completed. Therefore, the numerical controller 30 can shorten the time required to turn on the spindle motor 54 , and thus can quickly rotate the spindle 9 after the spindle head 7 reaches the Z-axis origin at t72 . The waiting time W4 from t74 to t75 is the time obtained by subtracting the movement time of the spindle head 7 (time required to move from the Z-axis origin to the target position) from the time required for the spindle rotation speed to reach the target value. Therefore, the numerical controller 30 can shorten the waiting time W4 by the time it takes for the spindle motor 54 to be turned on.

In this embodiment, the tapping command (G77) in mode B and the tool change command (G100) in mode G were described as an example of generating a plurality of movement commands by interpreting the NC program block by block. Instruction (S81) is also interpreted by the CPU 31 to generate three movement instructions. In this embodiment, an example of an NC program for a drilling operation using a drilling command is shown below.

As shown in FIG. 20 , the drilling operation includes, for example, three operations of a fast-forward operation 201 , a cutting feed operation 202 , and a fast-forward operation 203 . The fast-forward operation 201 is, for example, an operation for rotating the main shaft 9 and moving in a fast-forward manner from Z100 to the reference point (R point) of Z40. The cutting feed operation 202 is, for example, an operation of moving from point R to Z20 and rotating the main shaft 9 in one direction to drill a hole in a workpiece. The fast-forward operation 203 is an operation in which the main shaft 9 is moved back from the bottom of the hole toward Z100 in fast-forward without rotating. Therefore, the CPU 31 interprets the drilling command, and generates three internal commands corresponding to the three operations of the fast-forward operation 201 , the cutting feed operation 202 , and the fast-forward operation 203 .

The internal command corresponding to the fast-forward operation 201 needs to rotate the spindle 9, and therefore includes a spindle rotation command. Therefore, by setting the motion of the axis movement (for example, fast forward) before the fast forward motion 201, the drilling motion corresponds to the motion of the mode A. In this case, the numerical control device 30 can give the spindle motor 54 an ON command before starting the fast forward operation 201 , so that the waiting time W1 until the next fast forward operation 201 starts can be shortened.

In the above description, the CPU 31 of the numerical controller 30 is an example of the control unit of the present invention. The machine tool 1 is an example of the equipment of the present invention. The CPU 31 that executes the process of S5 is an example of the first judging unit of the present invention. The CPU 31 executing the process of S6 is an example of the second judging unit of the present invention. The CPU 31 executing the process of S10 is an example of the energization control unit of the present invention. The CPU 31 that executes the process of S12 is an example of the rotation execution unit of the present invention. The operation panel 15 is an example of the setting unit of the present invention.

In the mode B, the fast-forward command of the fast-forward operation 151 is an example of the axis movement command of the present invention. The tapping command of the tapping operation 152 is an example of the cutting feed command of the present invention. The tapping command of the tapping operation 153 is an example of the withdrawal command of the present invention. In pattern G, the first step 101 is an example of the first raising operation of the present invention. The second step 102 is an example of the second raising operation of the present invention. The third step 103 is an example of the rotation operation of the present invention. The fourth step 104 is an example of the first lowering operation in the present invention. The fifth step 105 is an example of the second lowering operation of the present invention. The Z-axis origin is an example of the device origin of the present invention. The specified position Ps is an example of an upper limit value of a range in which energization of the motor can be switched from an off state to an on state.

As described above, the CPU 31 of the numerical controller 30 of the present embodiment interprets the control commands of the NC program, generates internal commands such as movement commands, and controls the operation of the machine tool 1 according to the generated internal commands. The machine tool 1 has a spindle 9 for mounting a tool holder 17 supporting a tool 4 . The CPU 31 judges whether the spindle motor 54 is powered off and whether the current operation of the machine tool 1 is axis movement. When it is determined that the power is off and the current operation of the machine tool 1 is axis movement, the CPU 31 determines whether or not a spindle rotation command is included in the movement command for the next operation. When it is determined that the movement command for the next operation includes the spindle rotation command, the CPU 31 switches the energization of the spindle motor 54 from OFF to ON before the axis movement is completed. Therefore, the numerical controller 30 can shorten the standby time until the spindle motor 54 is turned on to rotate the spindle 9 in the next operation.

The present invention is not limited to the above-described embodiments, and various modifications are possible. Modes A to G in the above-described embodiment are examples of target operation modes in which the spindle motor 54 is OFF, the current operation is axis movement, and the next operation includes an operation including a spindle rotation command, and operation modes other than these modes may be used. NC programs P1 to P7 are examples of NC programs for executing the operation modes of modes A to G, and are not limited to these NC programs P1 to P7. Control commands such as G command and M command in the NC program are also examples, and the operation may be set by control commands other than these commands.

The numerical controller 30 of the above-described embodiment performs acceleration and deceleration processing for smoothing the speed change by using a moving average filter with respect to the calculated moving speed of each axis. In the example of acceleration and deceleration processing shown in Fig. 9, for the sake of explanation, the case where processing is performed using a first-order moving average filter is described as an example, but processing can also be performed using a second-order or higher moving average filter. . Therefore, the numerical controller 30 can further absorb a sudden change in the moving speed of the tool 4 , and thus can effectively suppress the vibration of the machine tool 1 .

In the above-described embodiment, in the mode G, the designated position Ps at which the spindle motor 54 can be turned on is set in the fourth step 104, but the designated position Ps may not be set. That is, the determination process of S9 in FIG. 12 may be omitted.

In this embodiment, instead of the CPU 31 , a microcomputer, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or the like may be used as a processing device. Regarding the movement control processing, distributed processing may be performed by a plurality of processing devices. The ROM 32 for storing the program may be constituted by, for example, HDD and/or other non-transitory storage media such as flash memory such as the storage device 34 . The non-transitory storage medium may be any storage medium as long as it can retain information regardless of the storage period of the information. Non-transitory storage media may also exclude transitory storage media (eg, transmitted signals). The mobility control program may be downloaded (that is, transmitted as a transmission signal) from a server connected to a network not shown, for example, and may be stored in the storage device 34 or the like. In this case, the movement control program may be stored in a non-transitory storage medium such as an HDD installed in the server.

Claims (10)

1. A numerical control device, comprising a control unit (31), the control unit (31) interprets a control command of an NC program to generate an internal command, and controls the operation of the device (1) according to the generated internal command control, the numerical control device is characterized in that, The device has a spindle (9) for mounting a tool (4), The control unit has: a first judging unit that judges whether the motor (54) for rotationally driving the main shaft is powered off and the current action of the device is shaft movement; The second determination unit is configured to determine that the internal command for the next operation is performed when the first determination unit determines that the energization of the motor is off and the current operation is shaft movement. whether to include a spindle rotation command to rotate the spindle; and The energization control unit, when the second determination unit determines that the spindle rotation command is included in the internal command for the next operation, the energization control unit stops the energization of the motor from The off state is switched to the on state. 2. The numerical controller according to claim 1, wherein: The control unit further includes a rotation execution unit configured to execute the rotation execution unit when the internal command for the next operation is executed after the shaft movement is completed after the energization control unit turns on the energization of the motor. The execution unit executes the spindle rotation command. 3. The numerical controller according to claim 1, wherein: When the control command of the NC program is a tapping command for performing tapping on a workpiece, The control unit generates a shaft movement command, a cutting feed command, and a withdrawal command as the internal command, The axis movement command is used to move the axis from a current position to a reference point where machining starts in the workpiece while the motor is powered off, The cutting feed command includes the spindle rotation command for rotating the spindle, and rotates the spindle from the reference point to the target position of the workpiece according to the spindle rotation command. cutting feed, The exit command is used to rotate the main shaft in a direction opposite to a rotation direction during the cutting feed after the cutting feed is performed to the target position, and is used to rotate the main shaft to the target position. the axis moves out of the hole formed in the workpiece, When the first judging unit judges that the energization of the motor is off and the current operation is a shaft movement corresponding to the shaft moving command, and the second judging unit judges that the motor is in the When the cutting feed command of the internal command of one operation includes the spindle rotation command, The energization control unit switches energization of the motor from an off state to an on state before the axis movement to the reference point as the current operation is completed. 4. The numerical controller according to claim 2, wherein: When the control command of the NC program is a tapping command for performing tapping on a workpiece, The control unit generates a shaft movement command, a cutting feed command, and a withdrawal command as the internal command, The axis movement command is used to move the axis from a current position to a reference point where machining starts in the workpiece while the motor is powered off, The cutting feed command includes the spindle rotation command for rotating the spindle, and rotates the spindle from the reference point to the target position of the workpiece according to the spindle rotation command. cutting feed, The exit command is used to rotate the main shaft in a direction opposite to a rotation direction during the cutting feed after the cutting feed is performed to the target position, and is used to rotate the main shaft to the target position. the axis moves out of the hole formed in the workpiece, When the first judging unit judges that the energization of the motor is off and the current operation is a shaft movement corresponding to the shaft moving command, and the second judging unit judges that the motor is in the When the cutting feed command of the internal command of one operation includes the spindle rotation command, The energization control unit switches energization of the motor from an off state to an on state before the axis movement to the reference point as the current operation is completed. 5. The numerical controller according to claim 1, wherein: The device has: a spindle head (7) supporting the spindle in such a manner that the spindle is rotatable, and configured to be movable in an up and down direction; and a tool magazine (21), the tool magazine rotates and supports a tool when the spindle head is located at an ATC origin, and the ATC origin is a position above the equipment origin within the vertical movement range of the spindle head, The device is capable of performing a tool change action, which includes the following actions: The first lifting action is to make the spindle head rise from the current position to the origin of the equipment; The second raising action is to make the spindle head rise from the origin of the equipment to the origin of the ATC. During this period, the current tool currently installed on the spindle is removed and handed over to the tool magazine; a rotating action, when the spindle head is located at the ATC origin, the tool magazine is rotated to position the next tool to be installed on the spindle so as to face the spindle; A first descending action, causing the spindle head to descend from the ATC origin to the equipment origin, during which time the next tool is received from the tool magazine and installed on the spindle; and The second lowering action is to lower the spindle head from the origin of the device to the target position, during which time the spindle is rotated, When the control command of the NC program is a tool change command for instructing the tool change operation, The control unit generates a first ascending command, a second ascending command, a rotation command, a first descending command, and a second descending command as the internal command, The first ascending command is used to instruct the shaft movement of the first ascending action, The second ascending command is used to instruct the shaft movement of the second ascending action, The rotation instruction is used to indicate the rotation action, The first descending command is used to instruct the shaft movement of the first descending action, the second lowering command is for instructing axis movement of the second lowering motion and includes the spindle rotation command for rotating the spindle, The first judging unit judges that the energization of the motor is off and the current operation is a shaft movement corresponding to the first lowering command, and the second judging unit judges that the motor is in the When the second descending command of the internal command in the next operation includes the spindle rotation command, The energization control unit switches energization of the motor from an off state to an on state before the axis movement to the device origin in the first lowering operation is completed. 6. The numerical controller according to claim 2, wherein: The device has: a spindle head that supports the spindle in such a manner that the spindle is rotatable, and is configured to be movable in an up and down direction; and a tool magazine that rotates and supports a tool when the spindle head is located at an ATC origin, the ATC origin being a position above the equipment origin within the vertical movement range of the spindle head, The device is capable of performing a tool change action, which includes the following actions: The first lifting action is to make the spindle head rise from the current position to the origin of the equipment; The second raising action is to make the spindle head rise from the origin of the equipment to the origin of the ATC. During this period, the current tool currently installed on the spindle is removed and handed over to the tool magazine; a rotating action, when the spindle head is located at the ATC origin, the tool magazine is rotated to position the next tool to be installed on the spindle so as to face the spindle; A first descending action, causing the spindle head to descend from the ATC origin to the equipment origin, during which time the next tool is received from the tool magazine and installed on the spindle; and The second lowering action is to lower the spindle head from the origin of the device to the target position, during which time the spindle is rotated, When the control command of the NC program is a tool change command for instructing the tool change operation, The control unit generates a first ascending command, a second ascending command, a rotation command, a first descending command, and a second descending command as the internal command, The first ascending command is used to instruct the shaft movement of the first ascending action, The second ascending command is used to instruct the shaft movement of the second ascending action, The rotation instruction is used to indicate the rotation action, The first descending command is used to instruct the shaft movement of the first descending action, the second lowering command is for instructing axis movement of the second lowering motion and includes the spindle rotation command for rotating the spindle, The first judging unit judges that the energization of the motor is off and the current operation is a shaft movement corresponding to the first lowering command, and the second judging unit judges that the motor is in the When the second descending command of the internal command in the next operation includes the spindle rotation command, The energization control unit switches energization of the motor from an off state to an on state before the axis movement to the device origin in the first lowering operation is completed. 7. The numerical controller according to claim 3, wherein: The device has: a spindle head that supports the spindle in such a manner that the spindle is rotatable, and is configured to be movable in an up and down direction; and a tool magazine that rotates and supports a tool when the spindle head is located at an ATC origin, the ATC origin being a position above the equipment origin within the vertical movement range of the spindle head, The device is capable of performing a tool change action, which includes the following actions: The first lifting action is to make the spindle head rise from the current position to the origin of the equipment; The second raising action is to make the spindle head rise from the origin of the equipment to the origin of the ATC. During this period, the current tool currently installed on the spindle is removed and handed over to the tool magazine; a rotating action, when the spindle head is located at the ATC origin, the tool magazine is rotated to position the next tool to be installed on the spindle so as to face the spindle; A first descending action, causing the spindle head to descend from the ATC origin to the equipment origin, during which time the next tool is received from the tool magazine and installed on the spindle; and The second lowering action is to lower the spindle head from the origin of the device to the target position, during which time the spindle is rotated, When the control command of the NC program is a tool change command for instructing the tool change operation, The control unit generates a first ascending command, a second ascending command, a rotation command, a first descending command, and a second descending command as the internal command, The first ascending command is used to instruct the shaft movement of the first ascending action, The second ascending command is used to instruct the shaft movement of the second ascending action, The rotation instruction is used to indicate the rotation action, The first descending command is used to instruct the shaft movement of the first descending action, the second lowering command is for instructing axis movement of the second lowering motion and includes the spindle rotation command for rotating the spindle, The first judging unit judges that the energization of the motor is off and the current operation is a shaft movement corresponding to the first lowering command, and the second judging unit judges that the motor is in the When the second descending command of the internal command in the next operation includes the spindle rotation command, The energization control unit switches energization of the motor from an off state to an on state before the axis movement to the device origin in the first lowering operation is completed. 8. The numerical controller according to claim 4, wherein: The device has: a spindle head that supports the spindle in such a manner that the spindle is rotatable, and is configured to be movable in an up and down direction; and a tool magazine that rotates and supports a tool when the spindle head is located at an ATC origin, the ATC origin being a position above the equipment origin within the vertical movement range of the spindle head, The device is capable of performing a tool change action, which includes the following actions: The first lifting action is to make the spindle head rise from the current position to the origin of the equipment; The second raising action is to make the spindle head rise from the origin of the equipment to the origin of the ATC. During this period, the current tool currently installed on the spindle is removed and handed over to the tool magazine; a rotating action, when the spindle head is located at the ATC origin, the tool magazine is rotated to position the next tool to be installed on the spindle so as to face the spindle; A first descending action, causing the spindle head to descend from the ATC origin to the equipment origin, during which time the next tool is received from the tool magazine and installed on the spindle; and The second lowering action is to lower the spindle head from the origin of the device to the target position, during which time the spindle is rotated, When the control command of the NC program is a tool change command for instructing the tool change operation, The control unit generates a first ascending command, a second ascending command, a rotation command, a first descending command, and a second descending command as the internal command, The first ascending command is used to instruct the shaft movement of the first ascending action, The second ascending command is used to instruct the shaft movement of the second ascending action, The rotation instruction is used to indicate the rotation action, The first descending command is used to instruct the shaft movement of the first descending action, the second lowering command is for instructing axis movement of the second lowering motion and includes the spindle rotation command for rotating the spindle, The first judging unit judges that the energization of the motor is off and the current operation is a shaft movement corresponding to the first lowering command, and the second judging unit judges that the motor is in the When the second descending command of the internal command in the next operation includes the spindle rotation command, The energization control unit switches energization of the motor from an off state to an on state before the axis movement to the device origin in the first lowering operation is completed. 9. The numerical controller according to any one of claims 5 to 8, further comprising a setting unit (15) capable of setting an upper limit value of the following range, This range is a range in which the energization control unit can control the energization of the motor from below a predetermined position where the tool is attached to the main shaft and above the origin of the device during the first lowering operation. range from the off state to the on state, The first judging unit judges that the energization of the motor is off and the current operation is a shaft movement corresponding to the first lowering command, and the second judging unit judges that the motor is in the When the second descending command of the internal command in the next operation includes the spindle rotation command and is equal to or less than the upper limit value set by the setting unit in the first descending operation, the The energization control unit switches energization of the motor from an off state to an on state before the axis movement to the origin of the device is completed. 10. A control method for a numerical control device, comprising a control step, in which, a control command of an NC program is interpreted to generate an internal command, and an internal command for installing a tool is executed according to the generated internal command. The action of the spindle device is controlled, and the control method is characterized in that, Described control step comprises the following steps: The first judging step is judging whether the motor for rotationally driving the main shaft is powered off and the current action of the device controlled in the controlling step is shaft movement; In the second judging step, when it is judged in the first judging step that the energization of the motor is off and the current action is shaft movement, it is judged whether the internal command for the next action includes a a spindle rotation command for said spindle rotation; and In the energization control step, when it is determined in the second determination step that the main shaft rotation command is included in the internal command for the next operation, the energization of the motor is switched from the OFF state until the movement of the shaft is completed. Switch to on state.