JP2021064363A - Numerical value control unit and control method - Google Patents

Abstract

To provide a numerical value control unit and a control method that can reduce the operation time for cutting.SOLUTION: The present invention relates to a numerical value control unit and a control method. The numerical value control unit moves a tool from the m-th cutting position toward the m+1-th cutting position in the horizontal direction. In the process of relative movement of the tool from the m-th cutting position to the m+1-th cutting position, the numerical value control unit moves the tool upward to a coasting position. While the tool moving to the coasting position passes through the m-th end position from the coasting position, the numerical value control unit calculates a start time to start relative movement of the tool downward from the coasting position, so that the tool reaches the m+1-th cutting position. When the tool reaches the coasting position and the calculated start time is reached, the numerical value control unit moves the tool from the coasting position downward to the m+1-th start position through the m-th end position.SELECTED DRAWING: Figure 3

Description

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

In the numerical control device described in Patent Document 1, the Z-axis motor moves the spindle head upward from the completion position of the cutting operation toward the return position, and further coasts the spindle head upward to a position beyond the return position. At this time, the numerical control device maintains the speed of the Z-axis motor until the spindle head reaches the return position from the completion position. Therefore, the numerical control device can shorten the time for moving the spindle head from the completion position to the return position. The numerical control device moves the spindle head during coasting movement in the horizontal direction to position it, and then moves the spindle head downward by the movement distance due to the coasting movement to return it to the original return position. The numerical control device moves the spindle head in the return position downward to the completion position and performs the next cutting operation.

JP-A-2009-237929

In order to shorten the cutting work time, not only the time to move the spindle head upward from the completion position to the return position but also the time to move the spindle head downward from the return position to the completion position during the cutting operation is shortened. Is valid. After stopping the spindle head once at the return position, the numerical control device starts moving the spindle head by the Z-axis motor and moves downward to the completion position. Therefore, since the time for moving the spindle head downward from the return position to the completion position during the cutting operation is relatively long, it may not be possible to shorten the cutting work time.

An object of the present invention is to provide a numerical control device and a control method capable of shortening the working time of cutting.

The numerical control device of the invention according to claim 1 has a first-axis motor that moves a tool relative to a workbench holding a work material in the first-axis direction and a second-axis direction that is orthogonal to the first-axis direction. It is a numerical control device that drives a second shaft motor that moves relative to the work material and controls the cutting process of cutting the work material, in order to position the relative position of the tool with respect to the work material in the process of the cutting process. The program includes a storage unit that stores a program including the command, and a control unit that positions the tool by controlling the first-axis motor and the second-axis motor based on the program. The mth machining position (m is an integer of 1 or more), the mth end position, the m + 1 start position, the m + 1 machining position, and the mth cutting that defines the position in the second axial direction. It is a command to move the tool between the position and the m + 1 cutting position, and the tool is moved to the workbench from the m cutting position to the m + 1 cutting position along the second axial direction. The nth command for relative movement (n is an integer of 1 or more), the tool is placed on the workbench in the proximity direction, which is the direction in which the tool is close to the workbench along the first axial direction. The n + 1 command for relative movement from the end position to the m + 1 start position, the tool is relatively moved to the m + 1 machining position in the proximity direction along the first axial direction with respect to the work table. The control unit includes at least the n + 2 command for relatively moving from the m + 1 processing position to the m + 1 end position in the separation direction, which is the direction away from the workbench, and the control unit is based on the nth command. The first moving portion that drives the shaft motor and moves the tool relative to the second axial direction from the mth cutting position to the m + 1 cutting position, and the tool is the first moving portion depending on the first moving portion. The first shaft motor is driven in the process of relative movement from the m cutting position to the m + 1 cutting position, and the tool is relative to the separation direction to a coasting position separated in the separation direction from the m end position. When the moving second moving portion and the tool that has been relatively moved to the coasting position by the second moving portion are relatively moved from the coasting position to the proximity direction and the tool passes the m-th end position. The first calculation unit calculates the start time when the tool starts the relative movement from the coasting position in the proximity direction so that the tool that moves relative to the first moving unit reaches the m + 1 cutting position. The tool reaches the coasting position according to the second moving unit, and depends on the first calculation unit. When the calculated start time arrives, the third movement that drives the first shaft motor and relatively moves the tool in the proximity direction from the coasting position to the m + 1 start position via the mth end position. It is characterized by having a part.

The numerical control device can maintain the velocity at the m-th end position when the tool is relatively moved downward. Therefore, the numerical control device can shorten the working time required for cutting the work material by the tool.

A second calculation unit that calculates the distance between the coasting position and the m-th end position of the numerical control device of the invention according to claim 2 as a coasting distance is provided, and the second moving unit is the second. The tool is relatively moved in the distance direction to the coasting position according to the coasting distance calculated by the calculation unit, and the second calculation unit is between the m end position and the m + 1 start position. The coasting distance is calculated based on the n + 1 command distance, which is the distance in the first axis direction, the maximum speed of the tool due to the drive of the first axis motor, and the time constant during acceleration / deceleration of the tool. At this time, the numerical control device can maximize the speed of the tool passing downward through the m-th end position, so that the working time required for cutting can be further shortened.

The second calculation unit of the numerical control device of the invention according to claim 3 moves relative to the proximity direction by the n + 1 command distance from the m end position while decelerating based on the time constant, and the m end. When the speed at the position is less than the maximum speed, it moves relative to the m-th end position while accelerating based on the time constant, and moves relative to the m-end position at the m-end position. The movement start position is determined to be the coasting position, and the distance between the determined coasting position and the mth end position is calculated as the coasting distance based on the n + 1 command distance. At that time, the numerical control device can easily calculate an appropriate coasting distance.

The third moving unit of the numerical control device of the invention according to claim 4 determines the speed during which the tool relatively moves from the coasting position toward the proximity direction by the coasting distance, based on the time constant. Accelerates to, and decelerates the speed during the relative movement of the tool in the proximity direction by the n + 1 command distance from the elapsed speed based on the time constant. At that time, the numerical control device can maximize the speed of the tool within the range of the time constant and the elapsed speed. Therefore, the numerical control device can reduce the time required for the tool to move relative from the mth end position to the m + 1th start position as much as possible.

The second calculation unit of the numerical control device of the invention according to claim 5 moves relative to the proximity direction by the n + 1 command distance from the m end position while decelerating based on the time constant. When the speed at the end position is the maximum speed, the relative movement start that reaches the maximum speed at the m end position when the relative movement toward the mth end position toward the mth end position while accelerating based on the time constant. The position is determined as the coasting position, and the distance between the determined coasting position and the m-th end position is calculated as the coasting distance based on the time constant and the maximum speed. At that time, the numerical control device can easily calculate an appropriate coasting distance.

The third moving unit of the numerical control device of the invention according to claim 6 determines the speed during which the tool moves relative to the coasting position by the coasting distance from the coasting position to the maximum speed based on the time constant. Accelerates to, and decelerates the speed while the tool moves relative to the proximity direction by the n + 1 command distance from the maximum speed based on the time constant. At that time, the numerical control device can maximize the speed of the tool within the range of the time constant and the maximum speed. Therefore, the numerical control device can reduce the time required for the tool to move relative from the mth end position to the m + 1th start position as much as possible.

The control method of the invention according to claim 7 is that the tool is relative to the workbench holding the work material from the mth cutting position (m is an integer of 1 or more) to the m + 1 cutting position along the second axial direction. The nth command for moving (n is an integer of 1 or more), the proximity direction in which the tool is close to the work table along the first axis direction orthogonal to the second axis direction with respect to the work table. The n + 1 command for relative movement from the mth end position to the m + 1 start position, the tool is relatively moved to the m + 1 machining position in the proximity direction along the first axial direction with respect to the workbench. Based on a program that includes at least the n + 2 command for relatively moving from the m + 1 machining position to the m + 1 end position in the separation direction, which is the direction away from the work table, the tool is placed on the work table. This is a control method for controlling a cutting process for cutting a work material by controlling a first-axis motor that moves relative to one axis and a second-axis motor that moves relative to the second axis, and the nth command. According to the first moving step of driving the second shaft motor and moving the tool relative to the second axis direction from the mth cutting position to the m + 1 cutting position, and the first moving step. In the process of the tool moving relative to the mth cutting position to the m + 1 cutting position, the first shaft motor is driven, and the tool is moved to a coasting position separated in the separation direction from the m end position. The second moving step that moves relative to the separation direction and the tool that has moved relative to the coasting position according to the second moving step are relatively moved from the coasting position to the proximity direction, and the tool moves relative to the m. When passing through the end position, the start time for starting the relative movement of the tool in the proximity direction from the coasting position is calculated so that the tool that moves relative to the first movement step reaches the m + 1 cutting position. When the tool reaches the coasting position according to the first calculation step and the start time calculated according to the first calculation step, the first shaft motor is driven. It is characterized by including a third moving step of relatively moving the tool in the proximity direction from the coasting position to the m + 1 start position via the mth end position. At that time, the same effect as that of Technical Plan 1 is obtained.

The left side view which shows the outline of the machine tool 10. The block diagram which shows the electrical structure of a numerical control device 20 and a machine tool 10. The figure which shows the relative movement locus of the tool 4 which moves based on the nth command to n + 2 command. The chart which shows the moving speed of a tool 4. A chart (X-axis direction) showing the moving speed of the tool 4. Flow diagram of main processing. The flow chart of the main processing following FIG. The flow chart of the first calculation process. The flow chart of the second calculation process. The flow chart of the third calculation process.

The machine tool 10 shown in FIG. 1 uses a tool 4 mounted on a spindle 9 to cut a work material W on a workbench 50. The numerical control device 20 of FIG. 2 controls the operation of the machine tool 10. The front side, rear side, left side, right side, upper side, and lower side of the machine tool 10 correspond to the left side, right side, back side, front side, upper side, and lower side of FIG. 1, respectively. The horizontal direction, the front-rear direction, and the vertical direction of the machine tool 10 are the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively.

As shown in FIG. 1, the machine tool 10 includes a base 2, a vertical column 5, a spindle head 7, a spindle 9, a workbench device 40, an operation panel 16 (see FIG. 2), and the like. In the machine tool 10, the workbench 50 of the workbench device 40 moves in the biaxial directions of the X-axis and the Y-axis. The base 2 is the base of the machine tool 10. The vertical column 5 is fixed to the rear part of the upper surface of the base 2. The spindle head 7 moves in the Z-axis direction along the front surface of the vertical column 5. The vertical column 5 is provided with a Z-axis moving mechanism on the front surface. The Z-axis movement mechanism uses a Z-axis motor 11 (see FIG. 2) as a drive source. The Z-axis moving mechanism has the same structure as the Y-axis moving mechanism described later. The spindle head 7 is provided with a spindle 9 rotatably inside. The tool 4 is mounted in the tool mounting hole provided at the lower end of the spindle 9.

The workbench device 40 is provided on the upper surface of the base 2 and below the spindle head 7. The workbench device 40 supports the workbench 50 so as to be movable in the biaxial directions of the X-axis and the Y-axis. In the workbench device 40 shown in FIG. 1, only the Y-axis moving mechanism that moves the workbench 50 in the Y-axis direction is shown, and the X-axis moving mechanism is omitted. The workbench device 40 includes a bed 41, a Y-axis track 42, a Y-axis motor 14, a joint 43, a ball screw 44, a bearing portion 45, a nut 46, a workbench 50, and the like. The bed 41, the Y-axis track 42, the Y-axis motor 14, the joint 43, the ball screw 44, the bearing portion 45, and the nut 46 form a Y-axis moving mechanism. The bed 41 is installed on the upper surface of the base 2. The bed 41 is provided with a recess that is long in the Y-axis direction at the center in the left-right direction, and most of the Y-axis moving mechanism is stored inside the recess. The Y-axis track 42 is provided on the upper part of the bed 41 and extends in the Y-axis direction. The Y-axis track 42 guides the workbench 50 so as to be movable in the Y-axis direction. The Y-axis motor 14 is provided on the rear side of the recess of the bed 41. The ball screw 44 is provided inside the recess of the bed 41 and extends in the Y-axis direction. The joint 43 connects the output shaft of the Y-axis motor 14 and the rear end of the ball screw 44 to each other. The bearing portion 45 rotatably supports the front end portion of the ball screw 44. Therefore, when the output shaft of the Y-axis motor 14 rotates, the ball screw 44 rotates via the joint 43. The nut 46 is fixed to the lower surface of the work table 50 and screwed into the ball screw 44. Therefore, as the ball screw 44 rotates, the workbench 50 moves in the Y-axis direction together with the nut 46. The workbench device 40 includes an X-axis movement mechanism in addition to the Y-axis movement mechanism. The X-axis moving mechanism supports the Y-axis moving mechanism so as to be movable in the X-axis direction. The X-axis movement mechanism is driven by the X-axis motor 13 (see FIG. 2) and has the same structure as the Y-axis movement mechanism.

Hereinafter, moving the workbench 50 holding the work material W in the X-axis direction with respect to the tool 4 according to the X-axis movement mechanism, and moving the tool 4 in the X-axis direction (with respect to the work material W) In other words, move. When the workbench 50 holding the work material W is moved in the Y-axis direction with respect to the tool 4 according to the Y-axis movement mechanism, and when the tool 4 is moved in the Y-axis direction (with respect to the work material W). In other words.

As shown in FIG. 2, the operation panel 16 includes an input unit 17 and a display unit 18. The input unit 17 is a device for performing various inputs, instructions, settings, and the like. The display unit 18 is a device that displays various screens. The numerical control device 20 includes a CPU 21, a ROM 22, a RAM 23, a storage device 24, an input / output unit 25, drive circuits 26 to 29, and the like. The CPU 21 controls the numerical control device 20 in an integrated manner. The ROM 22 stores a program and a set value for the CPU 21 to execute the main process. The RAM 23 stores various data during execution of various processes. The storage device 24 is a non-volatile memory and stores various parameters and the like in addition to the NC program. The NC program describes the operation of the machine tool 10 with a plurality of control commands depending on a predetermined program language. Each control command is a command for positioning the tool 4 in the process of cutting by the machine tool 10. Various parameters include the maximum speed Vxmax (maximum speed of the X-axis motor 13), Vymax (maximum speed of the Y-axis motor 14), Vzmax (maximum speed of the Z-axis motor 11), and the time constants Cx, Cy, and Cz described later. The input / output unit 25 is connected to the operation panel 16, the CPU 21, the ROM 22, the RAM 23, the storage device 24, and the drive circuits 26 to 29. The drive circuits 26 to 29 are servo amplifiers. The Z-axis motor 11 includes an encoder 11A. The spindle motor 12 includes an encoder 12A. The X-axis motor 13 includes an encoder 13A. The Y-axis motor 14 includes an encoder 14A. The drive circuit 26 is connected to the Z-axis motor 11 and the encoder 11A. The drive circuit 27 is connected to the spindle motor 12 and the encoder 12A. The drive circuit 28 is connected to the X-axis motor 13 and the encoder 13A. The drive circuit 29 is connected to the Y-axis motor 14 and the encoder 14A. The drive circuits 26 to 29 are collectively referred to as a drive circuit 30. The Z-axis motor 11, the spindle motor 12, the X-axis motor 13, and the Y-axis motor 14 are collectively referred to as a motor 15. Encoders 11A to 14A are collectively referred to as encoders 15A. The detection result output by the encoder 15A to the drive circuit 30 shows the positional relationship between the tool 4 and the work material W in the X-axis direction, the Y-axis direction, and the Z-axis direction. The CPU 21 reads the NC program stored in the storage device 24, and transmits a drive signal for positioning the tool 4 to the target position based on the control command to the drive circuit 30. The drive circuit 30 outputs a drive current to the corresponding motor 15 in response to the drive signal received from the CPU 21. The drive circuit 30 receives a feedback signal from the encoder 15A and controls the position and speed of the motor 15.

Indicates when the machine tool 10 is driven based on an NC program command (referred to as a feed axis command) for moving the tool 4 in the X-axis direction, the Y-axis direction, and the Z-axis direction with respect to the work material W. The time when the tool 4 is moved in the Z-axis direction with respect to the work material W to be machined will be described. The same applies when the tool 4 is moved with respect to the work material W in the X-axis direction and the Y-axis direction, respectively.

When the CPU 21 reads the feed axis command of the NC program, the spindle head 7 holding the spindle 9 moves to a position specified by the feed axis command, so that time-series data of the target position of the spindle head 7 is generated. The CPU 21 outputs the data of the target position to the drive circuit 26 at a predetermined cycle. The drive circuit 26 drives the Z-axis motor 11 based on the target position data output by the CPU 21. The Z-axis motor 11 moves the tool 4 to the target position in the Z-axis direction via the spindle head 7. Each time the CPU 21 inputs the data of the target position to the drive circuit 26, the drive circuit 26 drives the Z-axis motor 11. As a result, the tool 4 finally reaches the position (referred to as the command position) specified by the feed axis command. The control executed by the CPU 21 based on the feed axis command is referred to as feed axis control.

When the CPU 21 generates time-series data of the target position, the CPU 21 first determines each target position so that the speed at which the tool 4 moves in the Z-axis direction to the command position remains constant. Next, the CPU 21 applies a moving average filter to a waveform (referred to as a velocity waveform) indicating a time-series change in velocity, and adjusts acceleration / deceleration characteristics corresponding to the rising and falling characteristics of the velocity waveform. The moving average filter is a digital filter having an impulse response for a finite time, that is, an FIR filter. The process of applying the moving average filter to the velocity waveform to adjust the acceleration / deceleration characteristics is called the acceleration / deceleration process. The slopes of the rising and falling speed waveforms for which acceleration / deceleration processing is executed correspond to the acceleration / deceleration at the start and end of rotation of the Z-axis motor 11, and fluctuate based on the time constant Cz of the moving average filter.

The CPU 21 determines the target position for each predetermined cycle based on the speed waveform obtained by executing the acceleration / deceleration process. The CPU 21 outputs the determined target position data to the drive circuit 26 at a predetermined cycle. At this time, the tool 4 that moves by the Z-axis motor 11 driven by the drive circuit 26 accelerates at the acceleration based on the time constant Cz of the moving average filter at the start of movement, and reaches the time constant Cz of the moving average filter at the end of movement. Decelerate with the based acceleration. The time constant of the moving average filter applied when moving the workbench 50 in the X-axis direction by the same method as above is called Cx, and the time constant of the moving average filter applied when moving the workbench 50 in the Y-axis direction is Cy. Called.

An outline of drilling will be described as an example of the operation of the machine tool 10. In the drilling process, the tool 4 is moved in the Z-axis direction with respect to the work material W to form a hole extending in parallel with the Z-axis direction in the work material W. For example, the NC program for forming the m + 1 hole (m is an integer of 0 or more) in the work material W has at least the nth command (n is an integer of 1 or more), the n + 1 command, and the n + 2 command as feed axis commands. Including any. The nth command, the n + 1 command, and the n + 2 command are collectively referred to as the N command. The CPU 21 executes the commands in the order of the ordinal number N.

FIG. 3 shows the transition of the relative positions of the tool 4 with respect to the work table 50 and the work material W with reference to the work table 50 and the work material W. As shown in FIG. 3, the machine tool 10 moves the tool 4 from the mth cutting position to the m + 1 cutting position in the X and Y axis directions, and forms the m + 1 hole at the m + 1 cutting position in the X and Y axis directions. Take time as an example. The mth end position indicates the initial position of the tool 4. The first m + 1 start position, the first m + 1 machining position, and the first m + 1 end position indicate the command positions of the tool 4 to be positioned when forming the first m + 1 hole, respectively. The mth end position, the m + 1th start position, and the m + 1th end position are separated from the workbench 50 in the Z-axis direction. The m + 1th machining position overlaps with the work material W in the Z-axis direction. The positional relationship between the mth end position and the m + 1 end position in the Z-axis direction is not limited to FIG.

The nth command is a command for horizontally moving the tool 4 from the mth cutting position to the m + 1th cutting position along at least one of the X and Y axis directions. Since the tool 4 moves horizontally, the position of the tool 4 in the Z-axis direction after the movement based on the nth command is the same m end position as before the movement. Hereinafter, it is assumed that the tool 4 moves in the X-axis direction and does not move in the Y-axis direction based on the nth command. The moving distance of the tool 4 according to the nth command is referred to as the nth command distance Lxy.
The n + 1 command is a command for moving the tool 4 that has moved from the m cutting position to the m + 1 cutting position from the m end position to the m + 1 start position downward along the Z-axis direction based on the n command. .. The moving distance of the tool 4 according to the n + 1 command is referred to as the n + 1 command distance Lzdown.
The n + 2 command moves the tool 4 that has moved downward to the m + 1 start position based on the n + 1 command from the m + 1 start position to the m + 1 machining position downward along the Z-axis direction, and then moves downward from the m + 1 machining position. This is a command for moving upward along the Z-axis direction up to the m + 1 end position. The n + 2nd command may include two control commands. At this time, the first command is a command for moving the tool 4 which has moved downward to the m + 1 start position downward along the Z-axis direction from the m + 1 start position to the m + 1 machining position. The second command is a command for moving upward along the Z-axis direction from the m + 1 processing position to the m + 1 end position.

In the feed axis control of the numerical control device 20 (see FIGS. 3 and 4), the CPU 21 executes the feed axis control based on an NC program that repeatedly includes the nth command, the n + 1 command, and the n + 2 command. At that time, the NC program includes at least the nth command, the n + 1th command, and the n + 2 command. Since the drilling process is executed in a short time, it is preferable that the time required for the tool 4 to move downward from the mth end position to the m + 1 start position based on the n + 1 command is short. Therefore, when the tool 4 starts moving downward from the m-th end position, the initial velocity should be larger than 0. As shown in FIG. 3, when the CPU 21 moves the tool 4 from the mth cutting position to the m + 1 cutting position in the X-axis direction based on the nth command, at the same time, the CPU 21 moves the tool 4 from the m end position to the position above the m end position ( Move upward toward the coasting position). After the tool 4 reaches the coasting position, the CPU 21 moves the tool 4 downward from the coasting position to the mth end position before moving the tool 4 downward from the mth end position to the m + 1 start position based on the n + 1 command. Move to. At this time, the CPU 21 does not stop the tool 4 at the mth end position and continues to move downward to the m + 1 start position. Therefore, the CPU 21 can shorten the time required for the tool 4 to move from the m-th end position to the m + 1 start position, and can execute the drilling process in a short time.

Two operation types will be described with reference to FIG.

In FIG. 4A, the n + 1 command distance Lzdown (denoted as the command distance Lz) satisfies the relationship of the equation (1-1). Cz is the time constant and Vzmax is the maximum speed. The tool 4 that moves based on the n + 1th command moves downward by the command distance Lz while decelerating from the mth end position (time t55) based on the time constant Cz, and stops at the m + 1 start position (time t56). At this time, the moving speed when the tool 4 passes through the m-th end position is a elapsed speed Vzdown smaller than the maximum speed Vzmax. The command distance Lz is an integral value of the velocity straight line of the n + 1 command between the time t55 and t56. The time constant Cz is the elapsed time from when the tool 4 starts moving until the moving speed reaches the maximum speed Vzmax, and when the tool 4 starts decelerating from the maximum speed Vzmax, the tool 4 stops (moving speed is). It is the same as the elapsed time until (0).

ＣＰＵ２１は工具４が惰走位置から下向きに惰走距離Ｌｄ分移動する時の移動速度を時定数Ｃｚに基づき経過速度Ｖｚｄｏｗｎ迄加速する。ＣＰＵ２１は工具４が第ｍ終了位置から下向きに第ｎ＋１指令距離Ｌｄｏｗｎ移動する時の移動速度を経過速度Ｖｚｄｏｗｎから時定数Ｃｚに基づき０迄減速し、工具４を第ｍ＋１開始位置迄移動する。 When the tool 4 accelerates downward from the coasting position and reaches the elapsed speed Vzdown at the mth end position (time t55), the time t54, which is the start of movement of the tool 4, is based on the acceleration according to the time constant Cz. Determined according to the method of. The position of the tool 4 in the Z-axis direction at the time t54 is the coasting position. The distance in the Z-axis direction between the coasting position and the m-th end position (referred to as coasting distance Ld) is the integral value of the velocity straight line of the n + 1 command between the time t54 and t55, and the command distance Lz (= n + 1). It is equal to the command distance Lzdown). Therefore, the coasting distance Ld satisfies the relationship of Eq. (1-2).

The CPU 21 accelerates the moving speed when the tool 4 moves downward by the coasting distance Ld from the coasting position to the elapsed speed Vzdown based on the time constant Cz. The CPU 21 decelerates the moving speed when the tool 4 moves downward by the n + 1 command distance Ldown from the mth end position from the elapsed speed Vzdown to 0 based on the time constant Cz, and moves the tool 4 to the m + 1 start position.

When the tool 4 moves upward from the m-th end position to the coasting position, it accelerates from the time t51 based on the time constant Cz (time t51 to t52). The tool 4 moves by the coasting distance Ld, reaches the coasting position, and switches the moving speed from acceleration to deceleration so as to stop (time t52). The tool 4 decelerates based on the time constant Cz and stops at the coasting position (time t53). When the tool 4 starts moving upward toward the coasting position (time t51), the tool 4 starts moving in the X-axis direction by the nth command. The tool 4 starts moving in the X-axis direction from the mth cutting position. The tool 4 reaches the m + 1 cutting position at the time t55 and stops.

The CPU 21 calculates the time (movement time Txy) required for the tool 4 to move from the mth cutting position to the m + 1th cutting position. FIG. 5 is a chart showing the time change of the moving speed of the tool 4 in the X-axis direction. The maximum speed Vxmax is the moving speed of the tool 4 when the X-axis motor 13 is rotated at a predetermined maximum rotation speed. When the tool 4 starts moving in the X-axis direction, the moving speed of the tool 4 accelerates based on the time constant Cx. When the tool 4 finishes moving, the moving speed of the tool 4 decelerates based on the time constant Cx. The time constant Cx is the elapsed time from when the tool 4 starts moving in the X-axis direction until the moving speed reaches the maximum speed Vxmax, and when the tool 4 starts decelerating from the maximum speed Vxmax, the tool 4 stops (moving). It is the same as the elapsed time until the speed becomes 0). The area surrounded by the velocity straight line of the nth command and the horizontal axis is the nth command distance Lxy. FIG. 5A shows the time when the deceleration starts and returns to 0 before the moving speed of the tool 4 increases from 0 to the maximum speed Vxmax. The acceleration time and deceleration time at that time are referred to as Cx'. The maximum velocity Vxmax shows the relationship of the equation (1-3). The maximum speed at which the tool 4 moves is referred to as Vx.

At that time, the relationship of Vxmax / Cx = Vx / Cx'and Lxy = Cx'Vx / 2 is satisfied. When Cx'is obtained from the two equations, Txy matches the value obtained by doubling Cx', so the relationship of equation (1-4) is shown.

FIG. 5B shows the time when the moving speed of the tool 4 is increased and maintained from 0 to the maximum speed Vxmax, and then deceleration is started and the moving speed returns to 0. The maximum velocity Vxmax shows the relationship of the equation (1-5).

At this time, Txy shows the relationship of the formula (1-6).

The CPU 21 coasts so that the time when the tool 4 moving in the X-axis direction reaches the m + 1 cutting position by the nth command and the time when the tool 4 moving downward from the coasting position passes through the m end position coincide with each other. The time (time t54) at which the tool 4 at the position starts to move downward is determined as follows. As shown in FIG. 4, the time from when the tool 4 starts moving downward from the coasting position to when it passes through the m-th end position is referred to as Tzdown. The ratio of the maximum velocity Vzmax to the time constant Cz is consistent with the ratio of the elapsed velocity Vzdown to the time Tzdown. Therefore, the relation of equation (1-7) is satisfied.

Since the n + 1 command distance Lzdown is the integral value of the command straight line of the n + 1 command between the time t55 and t56, the relationship of the equation (1-8) is satisfied.

ｎ指令で工具４が移動開始する時機ｔ５１からの遅れ時間Ｔｄｅｌａｙは、式（１−１０）を満たす。

ＣＰＵ２１は式（１−４）又は（１−６）と、（１−９）（１−１０）を用いて時機ｔ５４を決定する。該時、ＣＰＵ２１は惰走位置からＺ軸方向に沿って下向きに移動した工具４が第ｍ終了位置を通過する時機ｔ５５で、ｎ指令で移動する工具４が第ｍ＋１切削位置に到達できる時機ｔ５４を決定する。 From equations (1-7) and (1-8), the time Tzdown satisfies the relationship of equation (1-9).

The delay time Tdelay from the time t51 when the tool 4 starts moving by the n command satisfies the equation (1-10).

The CPU 21 uses the equations (1-4) or (1-6) and (1-9) (1-10) to determine the time t54. At this time, the CPU 21 is a time t55 when the tool 4 moved downward along the Z-axis direction from the coasting position passes the mth end position, and a time t54 when the tool 4 moved by the n command can reach the m + 1 cutting position. To determine.

In FIG. 4B, the command distance Lz satisfies the relationship of the equation (2-1).

ＣＰＵ２１は工具４が惰走位置から下向きに惰走距離Ｌｄ分移動する時の速度を時定数Ｃｚに基づき最大速度Ｖｚｍａｘ迄加速する。工具４は惰走位置から第ｍ終了位置迄移動する。ＣＰＵ２１は工具４が第ｍ終了位置から下向きに第ｎ＋１指令距離Ｌｄｏｗｎ移動する時の速度を最大速度Ｖｚｍａｘで維持し、該後、時定数Ｃｚに基づき０迄減速する。該時、工具４は第ｍ＋１開始位置迄移動する。 When the tool 4 accelerates downward from the coasting position and reaches the maximum speed Vzmax at the mth end position (time t65), the time t64, which is the start time of the movement of the tool 4, is based on the time constant Cz and acceleration, and the following method is used. Determined according to. The position of the tool 4 in the Z-axis direction at the time t64 is the coasting position. The coasting distance Ld is an integral value of the velocity straight line of the n + 1 command between the times t64 and t65, and satisfies the relation of the equation (2-2).

The CPU 21 accelerates the speed at which the tool 4 moves downward by the coasting distance Ld from the coasting position to the maximum speed Vzmax based on the time constant Cz. The tool 4 moves from the coasting position to the m-th end position. The CPU 21 maintains the speed at which the tool 4 moves downward by the n + 1 command distance Ldown from the m-th end position at the maximum speed Vzmax, and then decelerates to 0 based on the time constant Cz. At this time, the tool 4 moves to the m + 1 start position.

ＣＰＵ２１はｎ指令で工具４が移動開始する時機ｔ６１からの遅れ時間Ｔｄｅｌａｙを式（２−３）を用いて算出し、時機ｔ６４を決定する。 When the tool 4 moves upward from the m-th end position to the coasting position, it accelerates from the time t61 based on the time constant Cz (time t61 to t62). The tool 4 moves by the coasting distance Ld, reaches the coasting position, and switches the moving speed from acceleration to deceleration so as to stop (time t62). The tool 4 starts deceleration based on the time constant Cz and then stops at the coasting position (time t63). When the tool 4 starts moving upward toward the coasting position (time t61), the tool 4 starts moving in the X-axis direction by the nth command. The tool 4 starts moving in the X-axis direction from the mth cutting position. The tool 4 reaches the m + 1 cutting position at the time t65. The time required for the tool 4 to move from the mth cutting position to the m + 1th cutting position is the movement time Txy. At this time, the CPU 21 coincides with the time when the tool 4 moving in the X-axis direction reaches the m + 1 cutting position by the nth command and the time when the tool 4 moving downward from the coasting position passes through the mth end position. Therefore, the time (time t64) at which the tool 4 in the coasting position starts to move downward is determined as follows. The delay time Tdelay from the time t61 when the tool 4 starts moving by the n command satisfies the relationship of the equation (2-3).

The CPU 21 calculates the delay time Tdelay from the time t61 when the tool 4 starts moving by the n command using the equation (2-3), and determines the time t64.

The main process will be described with reference to FIGS. 6 and 7. When the power of the machine tool 10 is turned on, the CPU 21 of the numerical control device 20 starts the main process by reading and executing the program stored in the ROM 22. At the start of the main process, the CPU 21 sets 1 in the variable n stored in the RAM 23. As shown in FIG. 6, the CPU 21 reads the nth command, the n + 1th command, and the n + 2 command from the NC program (S11). The CPU 21 determines whether the nth command is a control command for terminating the cutting process (S13). When the nth command is determined to be a control command for ending the cutting process (S13: YES), the CPU 21 ends the main process. When the CPU 21 determines that the nth command is not a control command for ending cutting (S13: NO), the n + 1 command is a feed axis command (Z axis) for moving the tool 4 downward along the Z axis direction. It is determined whether it is a downward command) (S15). When it is determined that the n + 1 command is not the Z-axis downward command (S15: NO), the CPU 21 controls the machine tool 10 based on the n command (S41). The CPU 21 adds 1 to the variable n stored in the RAM 23 (S43), and returns the process to S11. The CPU 21 repeats the process based on the updated variable n. When the CPU 21 determines that the n + 1 command is a Z-axis downward command (S15: YES), the CPU 21 determines whether the n-th command is a feed axis command (referred to as an X-axis command) for moving the tool 4 along the X-axis direction (referred to as an X-axis command). S17). When the CPU 21 determines that the nth command is not the X-axis command (S17: NO), the CPU 21 advances the process to S41. When the nth command is determined to be the X-axis command (S17: YES), the CPU 21 executes the first calculation process (see FIG. 8) in order to calculate the movement time Txy (S31).

The first calculation process will be described with reference to FIG. The CPU 21 determines whether the tool 4 starts decelerating and returns to 0 before the moving speed increases from 0 to the maximum speed Vxmax (S101). When the equation (1-3) is satisfied, the CPU 21 determines that the deceleration starts and returns to 0 before the moving speed of the tool 4 increases from 0 to the maximum speed Vxmax (S101: YES). At this time, the CPU 21 determines the travel time Txy based on the equation (1-4) (S103), and ends the first calculation process. When the CPU 21 does not satisfy the equation (1-3), it determines that the tool 4 increases and maintains the moving speed from 0 to the maximum speed Vxmax, then starts deceleration and returns to the moving speed 0 (S101: NO, equation (S101: NO, equation (S101: NO)). See 1-5)). At this time, the CPU 21 determines the travel time Txy based on the equation (1-6) (S105), and ends the first calculation process.

As shown in FIG. 6, the CPU 21 executes the second calculation process (see FIG. 9) in order to calculate the coasting distance Ld (S33). The second calculation process will be described with reference to FIG. The CPU 21 determines whether the tool 4 reaches the m-th end position before the moving speed of the tool 4 increases to the maximum speed Vzmax (S111). When the CPU 21 determines that the tool 4 reaches the m-th end position before the moving speed of the tool 4 increases to the maximum speed Vzmax based on the equation (1-1) (S111: YES), the CPU 21 determines the equation (1-2). Based on this, the n + 1 command distance Lzdown (= Lz) is determined as the coasting distance Ld (S113), and the second calculation process is terminated. When the CPU 21 determines that the tool 4 reaches the m-th end position after the moving speed of the tool 4 increases to the maximum speed Vzmax (S111: NO), the CPU 21 determines the coasting distance Ld based on the equation (2-2) (S115). , Ends the second calculation process.
As shown in FIG. 6, the CPU 21 calculates the time Tzdown (referred to as coasting distance movement time) from when the tool 4 starts moving downward from the coasting position to when it passes through the m-th end position, so that a third calculation process is performed. (See FIG. 10) is executed (S35). The third calculation process will be described with reference to FIG. The CPU 21 determines whether the tool 4 reaches the m-th end position before the moving speed of the tool 4 increases to the maximum speed Vzmax (S121). Based on the formula (1-1), when the CPU 21 determines that the tool 4 reaches the m-th end position before the moving speed of the tool 4 increases to the maximum speed Vzmax (S121: YES), the CPU 21 performs the formula (1-9). The coasting distance travel time Tzdown to be satisfied is determined (S123), and the third calculation process is completed. Based on the equation (2-1), when the CPU 21 determines that the tool 4 reaches the m-th end position after the moving speed of the tool 4 increases to the maximum speed Vzmax (S121: NO), the time constant is set as the coasting distance movement time Tzdown. Cz is determined (see S125, equation (2-3)), and the third calculation process is completed.

As shown in FIG. 6, the CPU 21 calculates the delay time in order to calculate the time when the tool 4 starts moving downward from the coasting position (S21). The delay time Tdeay subtracts the coasting distance travel time Tzdown calculated in the third calculation process (see S35) from the travel time Txy calculated in the first calculation process (see S31).
The CPU 21 drives the X-axis motor 13 and starts an operation of moving the tool 4 in the X-axis direction from the mth cutting position to the m + 1th cutting position (S23). At the same time, the CPU 21 drives the Z-axis motor 11 and starts an operation of moving the tool 4 upward from the m-th end position toward the coasting position (S23). The CPU 21 starts measuring the elapsed time from the start of the movement of the tool 4 in the X-axis direction (S29). The CPU 21 advances the process to S51 (see FIG. 7).

As shown in FIG. 7, the CPU 21 determines whether the elapsed time when the tool 4 which has started the upward movement according to S23 reaches the coasting position and the elapsed time when the measurement is started according to S29 coincides with the delay time Tdeliy and the start time has arrived. (S51). The CPU 21 does not reach the coasting position corresponding to the coasting distance Ld calculated by the second calculation process (see S33), or the elapsed time does not match the delay time Tdelay calculated by S21. When it is determined that the start time has not arrived (S51: NO), the process is returned to S51. When the CPU 21 determines that the tool 4 has reached the coasting position and the elapsed time coincides with the delay time Tdeli and the start time has arrived (S51: YES), the CPU 21 of the tool 4 moves from the coasting position to the m + 1 start position. The downward movement is started (S53). The time when the tool 4 which started the movement along the X-axis direction according to S23 reaches the m + 1 cutting position coincides with the time when the tool 4 which starts the downward movement according to S53 passes through the mth end position.

The CPU 21 determines whether the tool 4 that has started moving along the X-axis direction has reached the m + 1 cutting position according to S23 and the tool 4 that has started moving downward according to S53 has reached the m + 1 starting position (S55). ). When the tool 4 has not reached the m + 1 cutting position or the tool 4 has not reached the m + 1 starting position (S55: NO), the CPU 21 returns the process to S55 and repeats the process. When the tool 4 reaches the m + 1 cutting position and the tool 4 reaches the m + 1 starting position (S55: YES), the CPU 21 advances the process to S57. The CPU 21 moves the tool 4 which has moved downward to the m + 1 start position by the n + 2 command downward along the Z-axis direction from the m + 1 start position to the m + 1 machining position. The CPU 21 moves the tool 4 upward along the Z-axis direction from the m + 1 machining position to the m + 1 end position (S57). The CPU 21 adds 2 to the variable n stored in the RAM 23 (S59), and returns the process to S11 (see FIG. 6).

The numerical control device 20 calculates the coasting distance Ld and the delay time Tdeli (S33, S21). The tool 4 is moved from the mth cutting position to the m + 1th cutting position (S23), and at the same time, the tool 4 is moved upward to the coasting position (S23). When the delay time Tdeliy elapses (S51: YES) after the tool 4 reaches the coasting position and the tool 4 starts moving in the X-axis direction, the numerical control device 20 moves the tool 4 downward from the coasting position. It moves to the m + 1 start position via the m end position (S53). At this time, the numerical control device 20 can maintain the moving speed at the m-th end position when the tool 4 is moved downward. Therefore, the numerical control device 20 can shorten the working time required for cutting the work material W by the tool 4.

The numerical control device 20 calculates the coasting distance Ld based on the n + 1 command distance Lzdown when the moving speed of the tool 4 becomes the maximum at the elapsed speed Vzdown smaller than the maximum speed Vzmax (Equation (1-2)). At that time, the numerical control device 20 can easily calculate an appropriate coasting distance Ld. The numerical control device 20 accelerates the speed while the tool 4 moves downward by the coasting distance Ld from the coasting position to the elapsed speed Vzdown based on the time constant Cz. The numerical control device 20 decelerates the speed while the tool 4 moves downward by the n + 1 command distance Lzdown from the elapsed speed Vzdown based on the time constant Cz. At this time, the numerical control device 20 can maximize the moving speed of the tool 4 within the range of the time constant Cz and the elapsed speed Vzdown. Therefore, the numerical control device 20 can reduce the time required for the tool to move from the mth end position to the m + 1th start position as much as possible.

When the moving speed of the tool 4 becomes maximum at the maximum speed Vzmax, the numerical control device 20 calculates the coasting distance Ld based on the time constant Cz and the maximum speed Vzmax (Equation (2-2)). At that time, the numerical control device 20 can easily calculate an appropriate coasting distance Ld based on the time constant Cz and the maximum speed Vzmax. The numerical control device 20 accelerates the moving speed while the tool 4 moves downward from the coasting position by the coasting distance Ld to the maximum speed Vzmax based on the time constant Cz and maintains the maximum speed Vzmax. Next, the numerical control device 20 decelerates the moving speed while the tool 4 moves downward by the n + 1 command distance Lzdown from the maximum speed Vzmax based on the time constant Cz. At this time, the numerical control device 20 can maximize the moving speed of the tool 4 within the range of the time constant Cz and the maximum speed Vzmax. Therefore, the numerical control device 20 can reduce the time required for the tool 4 to move from the m-th end position to the m + 1 start position as much as possible.

The present invention is not limited to the above embodiment. The numerical control device 20 may add a predetermined movement amount to the calculated coasting distance Ld to obtain the coasting distance. At this time, the coasting position is further separated upward from the work material W with respect to the position determined above.

The numerical control device 20 may determine the start time for moving the tool 4 downward from the coasting position based on a variable other than the delay time Tdeli. For example, the numerical control device 20 may determine the amount of movement of the tool 4 in the X-axis direction based on the signal acquired from the encoder 13A connected to the X-axis motor 13. When the determined movement amount matches the predetermined threshold value, the numerical control device 20 may determine the start time for moving the tool 4 downward. The numerical control device 20 may calculate a predetermined threshold value in advance based on the delay time Tdelay, the command distance of the nth command, the time constant Cz, and the maximum speed Vzmax. At this time, the numerical control device 20 more accurately determines the time when the tool 4 reaches the m + 1 cutting position and the time when the tool 4 passes the mth end position, as compared with the time when the start time is determined based on the delay time Tdeli. Can match.

There are times when the command distance of the nth command is short. At this time, even if the tool 4 that has moved to the coasting position is immediately moved downward, the tool 4 moves in the X-axis direction to the m + 1 cutting position from the time when the tool 4 passes the m end position downward. There are times when the time to reach is faster. At that time, the working time of the cutting process becomes long, which is not preferable. At that time, a value obtained by subtracting a predetermined movement amount from the calculated coasting distance Ld may be determined as the coasting distance.

The machine tool 1 may move the tool 4 in the X and Y axis directions relative to the work material W by moving the tool 4 in the X and Y axis directions instead of the workbench 50. The machine tool 1 may move the tool 4 relative to the work material W in the Z-axis direction by moving the workbench 50 in the Z-axis direction instead of the spindle head 7.

The Z-axis direction is an example of the first-axis direction of the present invention. The Z-axis motor 11 is an example of the first-axis motor of the present invention. The X-axis direction and the Y-axis direction are examples of the second axis direction of the present invention. The X-axis motor 13 and the Y-axis motor 14 are examples of the second-axis motor of the present invention. The storage device 24 is an example of a storage unit of the present invention. Upward is an example of the separation direction of the present invention. The downward direction is an example of the proximity direction of the present invention. The CPU 21 that performs the processing of S21 is an example of the first calculation unit of the present invention. The CPU 21 that performs the processing of S33 is an example of the second calculation unit of the present invention. The CPU 21 that performs the processing of S23 is an example of the first moving unit and the second moving unit of the present invention. The CPU 21 that performs the processing of S53 is an example of the third moving unit of the present invention. The process of S21 is an example of the first calculation step of the present invention. The process of S33 is an example of the second calculation step of the present invention. The treatment of S23 is an example of the first moving step and the second moving step of the present invention. The treatment of S53 is an example of the third moving step of the present invention.

4: Tool 9: Spindle 10: Machine tool 11: Z-axis motor 12: Spindle motor 13: X-axis motor 14: Y-axis motor 20: Numerical control device 21: CPU
24: Storage device Cz: Time constant Ld: Coasting distance Vzmax: Maximum speed Vzup: Elapsed speed W: Work material

Claims (7)

A first-axis motor that moves the tool relative to the workbench holding the work material in the first-axis direction and a second-axis motor that moves relative to the second-axis direction orthogonal to the first-axis direction are driven. It is a numerical control device that controls the cutting process for cutting the work material.
A storage unit that stores a program including a command for positioning the relative position of the tool with respect to the work material in the process of cutting.
A control unit that controls the first-axis motor and the second-axis motor to position the tool based on the program is provided.
The program
The m end position (m is an integer of 1 or more) that defines the position in the first axial direction, the m + 1 start position, the m + 1 machining position, the m cutting position that defines the position in the second axial direction, and the m + 1 th. It is a command to move the tool between the cutting positions.
The nth command (n is an integer of 1 or more) for moving the tool relative to the workbench from the mth cutting position to the m + 1 cutting position along the second axial direction.
The n + 1 command for moving the tool relative to the workbench from the mth end position to the m + 1 start position in a proximity direction which is a direction close to the workbench along the first axial direction.
The tool is relatively moved to the m + 1 machining position in the proximity direction along the first axial direction with respect to the work table, and is separated from the work table from the m + 1 machining position. Includes at least the n + 2 command to move relative to the m + 1 end position, including
The control unit
A first moving portion that drives the second shaft motor based on the nth command and moves the tool relative to the second axis direction from the m cutting position to the m + 1 cutting position.
The first shaft motor was driven in the process of relative movement of the tool from the mth cutting position to the m + 1 cutting position by the first moving portion, and separated from the m end position in the separation direction. A second moving part that moves the tool relative to the separation direction to the coasting position, and
When the tool that has moved relative to the coasting position by the second moving portion is relatively moved from the coasting position to the proximity direction and the tool passes the m end position, it depends on the first moving portion. A first calculation unit that calculates a start time for starting the relative movement of the tool in the proximity direction from the coasting position so that the tool that moves relative to the tool reaches the m + 1 cutting position.
When the tool reaches the coasting position by the second moving unit and the start time calculated by the first calculating unit arrives, the first shaft motor is driven to drive the first shaft motor from the coasting position. A numerical control device including a third moving unit that relatively moves the tool in the proximity direction to the m + 1 start position via the m end position. It is provided with a second calculation unit that calculates the distance between the coasting position and the m-th end position as the coasting distance.
The second moving part is
The tool is relatively moved in the distance direction to the coasting position according to the coasting distance calculated by the second calculation unit.
The second calculation unit
The n + 1 command distance, which is the distance between the mth end position and the m + 1 start position in the first axis direction, the maximum speed of the tool due to the drive of the first axis motor, and acceleration / deceleration of the tool. The numerical control device according to claim 1, wherein the coasting distance is calculated based on a time constant of time. The second calculation unit
When the speed at the m-th end position is smaller than the maximum speed by moving relative to the proximity direction by the n + 1 command distance from the m-end position while decelerating based on the time constant, the time constant The coasting position is determined by determining the movement start position at which the elapsed speed is reached at the mth end position by moving relative to the proximity direction toward the mth end position while accelerating based on the above. The numerical control device according to claim 2, wherein the distance between the m-th end position and the m-th end position is calculated as the coasting distance based on the n + 1 command distance. The third moving part is
The speed during which the tool relatively moves from the coasting position to the proximity direction by the coasting distance is accelerated to the elapsed speed based on the time constant, and the tool is relative to the n + 1 command distance in the proximity direction. The numerical control device according to claim 3, wherein the speed during movement is decelerated from the elapsed speed based on the time constant. The second calculation unit
Accelerate based on the time constant when the speed at the m end position when moving relative to the proximity direction by the n + 1 command distance from the m end position while decelerating based on the time constant is the maximum speed. While moving relative to the m-th end position in the proximity direction, the relative movement start position having the maximum speed at the m-th end position is determined as the coasting position, and the determined coasting position and the said The numerical control device according to claim 2, wherein the distance between the m-th end positions is calculated as the coasting distance based on the time constant and the maximum speed. The third moving part is
The speed during which the tool relatively moves from the coasting position to the proximity direction by the coasting distance is accelerated to the maximum speed based on the time constant, and the tool is relative to the n + 1 command distance in the proximity direction. The numerical control device according to claim 5, wherein the speed during movement is decelerated from the maximum speed based on the time constant. The nth command (n is 1) for moving the tool relative to the workbench holding the work material from the mth cutting position (m is an integer of 1 or more) to the m + 1 cutting position along the second axial direction. (The above integer), from the m end position to the m + 1 start position in the proximity direction, which is the direction in which the tool is close to the work table along the first axis direction orthogonal to the second axis direction with respect to the work table. The n + 1 command for relative movement, the separation direction in which the tool moves relative to the workbench along the first axial direction to the m + 1 machining position in the proximity direction and is separated from the workbench. A first-axis motor that moves the tool relative to the workbench in the first-axis direction based on a program that includes at least an n + 2 command for relative movement from the m + 1 machining position to the m + 1 end position. It is a control method that controls a second shaft motor that moves relative to the second shaft direction to control a cutting process for cutting the work material.
A first moving step of driving the second shaft motor based on the nth command and relatively moving the tool from the m cutting position toward the m + 1 cutting position in the second axis direction.
According to the first moving step, the first shaft motor was driven in the process of relative movement of the tool from the mth cutting position to the m + 1 cutting position, and separated from the m end position in the separation direction. The second moving step of moving the tool relative to the separation direction to the coasting position, and
When the tool that has moved relative to the coasting position according to the second moving step is relatively moved from the coasting position to the proximity direction and the tool passes the m end position, the first moving step is used. The first calculation step of calculating the start time of starting the relative movement of the tool in the proximity direction from the coasting position so that the tool that moves relative to the tool reaches the m + 1 cutting position.
When the tool reaches the coasting position according to the second moving step and the start time calculated according to the first calculation step arrives, the first shaft motor is driven to drive the first shaft motor from the coasting position. A control method comprising a third moving step of relatively moving the tool in the proximity direction to the m + 1 start position via the m end position.

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