JP2018005423A - Control device of machine tool and machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a machine tool and the machine tool, which can be driven to vibrate at an arbitrary vibration number with respect to an arbitrary rotation number.SOLUTION: A control device 180 of a machine tool includes: workpiece holding means (illustrated as a chuck 120) for holding a workpiece; a cutting tool 130 for cutting the workpiece; rotation means for relatively rotating the workpiece and the cutting tool; and vibration means (illustrated as a Z-axis direction feed mechanism 160) which vibrates the workpiece and the cutting tool at a prescribed vibration number with respect to relative rotation by successively moving the workpiece holding means or the cutting tool toward a prescribed position. The control device of the machine tool machines the workpiece with vibration by the vibration means. The control device further includes a vibration means control section 191 which sets following responsiveness of the moving of the workpiece holding means or the cutting tool with respect to the prescribed position so that the workpiece holding means or the cutting tool moves with a change in a moving direction from a continuous one prescribed position side to the other prescribed position side.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a machine tool control device and a machine tool, and more particularly to a machine tool control device and a machine tool for machining a workpiece into a cutting tool at a predetermined vibration frequency.

  Conventionally, a work holding means for holding a work, a cutting tool for cutting the work, a rotating means for relatively rotating the work and the cutting tool, and the work holding means and the cutting tool are sequentially moved toward a predetermined position. And a vibration means for vibrating the workpiece and the cutting tool at a predetermined number of times with respect to relative rotation. By moving the workpiece holding means and the cutting tool relative to each other, vibration is caused by the vibration means. A machine tool for machining a workpiece is known (for example, Patent Document 1).

International Publication No. 2015/146946

By the way, it is desirable that the number of rotations of the rotating means and the number of vibrations by the vibrating means can be arbitrarily set depending on the processing conditions.
However, since the workpiece holding means and the cutting tool are sequentially moved toward the predetermined position, the movement direction is changed at the moved position, and the movement destination is the change position of the vibration direction. Therefore, any rotation desired by the operator can be obtained. There is a problem that it may not be possible to vibrate at an arbitrary number of vibrations with respect to the number.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a machine tool control device and a machine tool that can be driven to vibrate at an arbitrary number of vibrations with respect to an arbitrary number of rotations. To do.

  The present invention includes, firstly, a work holding means for holding a work, a cutting tool for cutting the work, a rotating means for relatively rotating the work and the cutting tool, and the work holding means or the Vibrating means for vibrating the workpiece and the cutting tool at a predetermined number of times with respect to the relative rotation by moving the cutting tool sequentially toward a predetermined position, the workpiece holding means and the cutting tool Is a control device for a machine tool that processes the workpiece with the vibration by the vibration means, wherein the workpiece holding means or the cutting tool is one continuous predetermined position. Movement of the work holding means or the cutting tool with respect to the predetermined position so as to move with a change in the moving direction from the side toward the other predetermined position side. Characterized by comprising a vibrating means control unit for setting the slave response.

  Secondly, the vibration means control unit sets the follow-up response of the movement by setting a gain of servo control.

  Third, it has amplitude setting means for setting the amplitude of the vibration based on the set gain so that the machining portion at the time of forward movement and the machining portion at the time of backward movement by the vibration means overlap. It is characterized by.

  4thly, it has the phase setting means which sets the phase of the said vibration based on the said following responsiveness set.

  Fifth, a work holding means for holding a work, a cutting tool for cutting the work, a rotating means for relatively rotating the work and the cutting tool, and the work holding means or the cutting tool are sequentially provided. Vibrating means for causing the workpiece and the cutting tool to vibrate at a predetermined number of vibrations relative to the relative rotation by moving the workpiece and the cutting tool relative to each other, the workpiece holding means and the cutting tool being relatively A machine tool for machining the workpiece with the vibration by the vibration means, wherein the workpiece holding means or the cutting tool is continuously moved from one predetermined position side to the other predetermined position side. The vibration means follows the movement of the work holding means or the cutting tool with respect to the predetermined position so as to move with a change of the moving direction toward Wherein the answers property is set.

The present invention can obtain the following effects.
(1) Arbitrary rotation of relative rotation by setting the follow-up response of the vibration means so as to move with a change in the moving direction from one continuous predetermined position side to the other predetermined position side Any number of vibrations can be easily realized with a number.

(2) The follow-up response can be easily performed by setting a servo control gain.

(3) Even if the follow-up response is changed, processing by desired vibration can be performed by setting the amplitude.

(4) Even if a phase advance or delay occurs due to the change in follow-up response, desired processing can be performed by setting to an arbitrary phase.

(5) A machine tool capable of easily obtaining an arbitrary number of vibrations at an arbitrary number of relative rotations can be provided.

It is a figure showing the outline of the machine tool by one example of the present invention. It is the schematic which shows the relationship between a cutting tool and a workpiece | work. It is a figure explaining the reciprocating vibration and position of a cutting tool. It is a figure which shows the relationship of the blade path | route at the time of each rotation of the nth rotation of a main axis | shaft, n + 1st rotation, and n + 2 rotation. It is a block diagram of a control apparatus. 3 is a flowchart of a machining process performed by a control unit according to the first embodiment. 6 is a flowchart of a correction process by a control unit according to the first embodiment. It is a figure explaining the blade edge | path route of Example 1. FIG. It is a figure explaining the blade edge | path route of Example 1. FIG. 10 is a flowchart of correction processing by a control unit according to the second embodiment. It is a figure explaining the blade edge | path route of Example 2. FIG. 10 is a flowchart of correction processing by a control unit according to the third embodiment. It is a figure explaining the blade edge | path route of Example 3. FIG.

A machine tool control device and a machine tool according to the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the machine tool 100 according to the present invention includes a main shaft 110, a cutting tool base 130 </ b> A, and a control device 180.

  A chuck 120 is provided at the tip of the main shaft 110. The main shaft 110 is used as a work holding means, and the work W is held on the main shaft 110 via the chuck 120. The spindle 110 is rotatably supported by the spindle stock 110A and is driven to rotate by the power of the spindle motor. The spindle motor may be a known built-in motor provided between the spindle stock 110A and the spindle 110, for example.

A Z-axis direction feed mechanism 160 is provided on the bed of the machine tool 100.
The Z-axis direction feed mechanism 160 includes a base 161 integrated with the bed, and a Z-axis direction guide rail 162 fixed to the base 161. A Z-axis direction feed table 163 is slidably supported on the Z-axis direction guide rail 162 via a Z-axis direction guide 164. The headstock 110 </ b> A is mounted on the Z-axis direction feed table 163. The headstock 110 </ b> A is arranged so that the axial direction of the main shaft 110 coincides with the extending direction of the Z-axis direction guide rail 162.

  The linear servo motor 165 includes a mover 165a and a stator 165b. The mover 165a is provided on the Z-axis direction feed table 163, and the stator 165b is provided on the base 161. When the Z-axis direction feed table 163 moves along the Z-axis direction guide rail 162 by driving the linear servo motor 165, the headstock 110A moves in the axial direction (Z-axis direction in the drawing) of the main shaft 110, and the main shaft 110 moves. It moves along the Z-axis direction via the headstock 110A.

The cutting tool base 130A constitutes a tool post on which a cutting tool 130 such as a cutting tool for processing the workpiece W is mounted and holds the cutting tool.
An X-axis direction feed mechanism 150 is provided on the bed side of the machine tool 100.

  The X-axis direction feed mechanism 150 includes a base 151 that is integral with the bed side, and an X-axis direction guide rail 152 that extends in the X-axis direction perpendicular to the Z-axis direction in the vertical direction. The X-axis direction guide rail 152 is fixed to the base 151, and an X-axis direction feed table 153 is slidably supported on the X-axis direction guide rail 152 via the X-axis direction guide 154. A cutting tool base 130A is mounted on the X-axis direction feed table 153.

  The linear servo motor 155 includes a mover 155a and a stator 155b. The mover 155a is provided on the feed table 153, and the stator 155b is provided on the base 151. When the X-axis direction feed table 153 is moved in the X-axis direction along the X-axis direction guide rail 152 by driving the linear servo motor 155, the cutting tool base 130A is moved in the X-axis direction, and the cutting tool 130 is moved in the X-axis direction. Moving.

A Y-axis direction feed mechanism may be provided. The Y-axis direction is a direction orthogonal to the illustrated Z-axis direction and X-axis direction. The Y-axis direction feed mechanism can have the same structure as the X-axis direction feed mechanism 150. By mounting the X-axis direction feed mechanism 150 on the bed via the Y-axis direction feed mechanism, the Y-axis direction feed table is moved in the Y-axis direction by driving the linear servo motor, and the cutting tool base 130A is moved in the X-axis direction. In addition, the cutting tool 130 can be moved in the X-axis direction and the Y-axis direction by moving in the Y-axis direction.
The Y-axis direction feed mechanism may be mounted on the bed via the X-axis direction feed mechanism 150, and the cutting tool table 130A may be mounted on the Y-axis direction feed table.

The rotation of the main shaft 110 and the movement of the X-axis direction feed mechanism 150, the Z-axis direction feed mechanism 160, and the like are controlled by the control device 180.
The X-axis direction feed mechanism 150 and the Z-axis direction feed mechanism 160 or a feed means including the Y-axis direction feed mechanism constitutes the X-axis direction feed mechanism 150 or the Y-axis direction feed mechanism and the Z-axis direction feed mechanism 160. By this cooperation, as shown in FIG. 2, the headstock 110A and the cutting tool base 130A can be moved to predetermined positions. By moving the headstock 110A and the cutting tool base 130A to predetermined positions, the cutting tool 130 is moved relative to the spindle 110, and the spindle 110 is moved relative to the workpiece W and the cutting tool 130. The workpiece W can be processed into a desired shape by being driven as a rotating means for rotating and rotating the workpiece W with respect to the cutting tool 130.

  In the present embodiment, both the headstock 110A and the cutting tool base 130A are configured to move. However, the headstock 110A is fixed to the bed, and the cutting tool base 130A is moved in the X-axis direction, the Y-axis direction, and the Z-axis direction. It may be movable. In this case, the feeding means is constituted by a feeding mechanism that moves the cutting tool base 130A. Alternatively, the cutting tool base 130A may be fixed, and the head stock 110A may be movable in the X axis direction, the Y axis direction, and the Z axis direction. In this case, the feeding means is constituted by a feeding mechanism provided on the bed.

In this embodiment, an example in which a linear servo motor is used for the X-axis direction feed mechanism 150 and the Z-axis direction feed mechanism 160 has been described. However, a known ball screw and servo motor may be used.
In the present embodiment, the workpiece W is rotated with respect to the cutting tool 130, but a rotary tool such as a drill may be used as the cutting tool 130 and the cutting tool 130 may be rotated with respect to the workpiece W. In this case, the motor that rotates the cutting tool 130 corresponds to the rotating means of the present invention.

The control device 180 moves the cutting tool base 130A forward (forward movement) by a predetermined forward amount along the feed direction as shown in FIG. By moving (reciprocating), the cutting tool 130 can be fed to the workpiece W in the feed direction by a difference (advance amount) between the advance amount and the reverse amount with vibration along the feed direction.
The vibrating means is constituted by feeding means including the X-axis direction feeding mechanism 150 and the Z-axis direction feeding mechanism 160 or the Y-axis direction feeding mechanism, and moves the headstock 110A and the cutting tool stage 130A forward and backward. Thus, the cutting tool 130 can be vibrated with respect to the workpiece W. The cutting tool 130 is fed along with the vibration along the feeding direction to the workpiece W by the feeding unit that also serves as the vibrating unit, and processes the workpiece W.

The cutting tool base 130A is sent along the feed direction during one rotation of the spindle 110, that is, while the spindle phase changes from 0 ° to 360 °, and the total of the above-mentioned progress amounts becomes the feed amount in the Z-axis direction.
As the cutting tool 130 processes the forward movement and the backward movement in the feed direction repeatedly, the peripheral surface of the workpiece W is processed into a sinusoidal shape by the cutting tool 130 as shown in FIG. FIG. 4 shows an example in which the number of vibrations N of the headstock 110 </ b> A per rotation of the main shaft 110 is 3.5 times (also referred to as the frequency N = 3.5).

The peripheral surface shape (indicated by a solid line in FIG. 4) of the workpiece W at the nth rotation (n is an integer of 1 or more) of the main shaft 110 processed by the cutting tool 130, and the peripheral surface of the workpiece W at the n + 1th rotation of the main shaft 110. The shape (indicated by a broken line in FIG. 4) is shifted in the main axis phase direction (the horizontal axis direction of the graph of FIG. 4).
The position of the lowest point of the valley in the circumferential shape of the workpiece W indicated by the broken line in FIG. 4 (the highest point of the peak in the cutting tool 130) is the lowest point of the valley in the circumferential shape of the workpiece W indicated by the solid line in FIG. It does not coincide with the position of the peak point of the cutting tool 130 in the main axis phase direction.

  Thereby, the cutting edge portion of the cutting tool 130 overlaps the cutting portion at the time of the forward movement and the cutting portion at the time of the next backward movement. Since the peripheral surface shape of the workpiece W at the n-th rotation of the spindle 110 is included, the cutting tool 130 performs an idling operation that does not process the workpiece W. During this idling operation, chips generated from the workpiece W are divided. The machine tool 100 smoothly processes the outer shape and the like of the workpiece W while cutting the chips.

  The number of vibrations N of the cutting tool base 130A (cutting tool 130) per rotation of the spindle 110 (work W) can be set to 1.1, 1.25, 2.6, 3.75 times, etc., for example. It can also be set to a value smaller than once. When the vibration frequency N is set to a value smaller than one, the spindle 110 rotates more than one rotation before the cutting tool base 130A makes one reciprocation. The number of vibrations N can also be set as the number of rotations of the main shaft 110 per vibration.

As illustrated in FIG. 5, the control device 180 includes, for example, a control unit 181, a numerical value setting unit 182, a display unit 183, and a storage unit 184, which are connected via a bus.
The control unit 181 includes a CPU and the like, and loads various programs and data stored in, for example, the ROM of the storage unit 184 into the RAM, and executes the program. Thereby, the operation of the machine tool 100 can be controlled based on the program. The storage unit 184 includes a table 194 for gain G1 and gain G2.
The gain G1 and the gain G2 indicate control gains in PID control of a servo motor that controls the Z-axis direction feed mechanism and the X-axis direction feed mechanism.

The reciprocating vibration of the cutting tool 130 by the vibration means is executed by the control unit 181 at a command frequency fc based on a predetermined command cycle T.
For example, when the control unit 181 can send an operation command 250 times per second, the operation command can be output in a cycle of 1/250 = 4 (ms) (also referred to as a reference cycle IT). In general, the command cycle T is an integral multiple of this reference cycle.

  When the command cycle T is 16 (ms), which is four times the reference cycle 4 (ms), for example, the motor control unit 190 causes the cutting tool 130 to perform reciprocating vibration every 16 (ms) along the feed direction. In addition, a drive signal is output to the Z-axis direction feed mechanism 160, the X-axis direction feed mechanism 150, or the Y-axis direction feed mechanism. In this case, the cutting tool 130 performs reciprocal vibration at a command frequency fc = 1 / T = 1 ÷ (0.004 × 4) = 62.5 (Hz) resulting from the command cycle T = 16 (ms). That is, by causing the movement of the cutting tool base 130A to follow the position commanded by the control unit 181, the cutting tool 130 is set to 20 (ms), which is 5 times the reference period, 24 (ms), which is 6 times, 7 The reciprocating vibration can be executed every 28 (ms) double and 32 (ms) eight times. In this case, the cutting tool 130 has a command frequency fc = 1 ÷ (0.004 × 5) = 50 (Hz), 1 ÷ (0.004 × 6) = 41.666 (Hz), 1 ÷ (0.004). Reciprocating vibration can be performed at a plurality of limited frequencies of x7) = 35.714 (Hz), 1 / (0.004 * 8) = 31.25 (Hz).

  If the rotation speed of the spindle 110 is S (r / min), the vibration frequency of the cutting tool 130 with respect to the rotation of the workpiece W is N (times), and the vibration frequency f (times / sec) of the cutting tool 130 with respect to the workpiece W is N is N = f × 60 / S. The rotation speed S and the vibration frequency N are inversely proportional to each other with the vibration frequency f as a constant, and the main shaft 110 can be rotated at a higher speed as the vibration frequency f is increased, and can be rotated at a higher speed as the vibration frequency N is decreased. it can.

  The control unit 181 rotates the spindle 110 at the rotation speed S and causes the cutting tool 130 to vibrate at the vibration frequency N while processing it in the feed direction. At this time, if the vibration frequency f at which the vibration frequency N is equal to the rotation speed S matches one of the plurality of limited command frequencies, the necessary command frequency is set as the target command frequency fc. The motor control unit 190 sets a gain G1 at which the head stock 110A or the cutting tool base 130A follows the operation command for each reference period so that the cutting tool 130 passes the position specified by the operation command for each reference period. . The gain G1 is set from the storage unit 184. The motor control unit 190 outputs an operation command to the linear servo motor 155 or the like for each reference period, and the spindle head 110A or the cutting tool table 130A moves following the coordinate position where the operation command is issued, thereby The cutting tool 130 can be vibrated at the frequency fc.

  On the other hand, when the vibration frequency f that becomes the vibration frequency N with respect to the rotation speed S does not coincide with any of the plurality of limited command frequencies, the motor control unit 190 causes the vibration waveform based on the vibration frequency f. An operation command for each reference cycle is output so that the cutting tool 130 moves to the target movement position, with the position corresponding to the predetermined command cycle as a target movement position. The motor control unit 190 sets the follow-up response of movement of the head stock 110A or the cutting tool base 130A by the gain G2. The gain G2 is set by, for example, calling from the table G194 for the gain G2 in the storage unit 184 by the vibration unit control unit 191. By setting the gain G2 in place of the gain G1, the sensitivity of servo control can be changed to adjust and set the follow-up response. By setting the gain G2, the follow-up responsiveness of the Z-axis direction feed mechanism 160, the X-axis direction feed mechanism 150, and the Y-axis direction feed mechanism is lowered and a follow-up delay occurs.

  The movement of the cutting tool 130 is performed toward the position commanded by the operation command with a follow-up delay. For example, the next operation command is issued before reaching the commanded position, whereby the cutting tool 130 is moved. Moves from one predetermined continuous position commanded by an operation command for each reference cycle toward the other position with a change in the moving direction. Thereby, the cutting tool 130 can be moved along the vibration waveform of the vibration frequency f where the inflection point is located during the reference period.

The rotation speed S, the vibration frequency N, and the vibration frequency f can be set by a machining program or input to the numerical value setting unit 182. Thereby, the cutting path (start point, end point, linear interpolation and circular interpolation) of the cutting tool 130 and the vibration conditions (the rotational speed S of the main shaft 110 and the vibration frequency N of the cutting tool 130 with respect to the rotation of the main shaft 110) are set. The
The control unit 181 obtains a vibration frequency f, and obtains a vibration waveform by superimposing vibration conditions on the cutting path (step S1 in FIG. 6).

  The controller 181 determines whether or not the vibration frequency f is an integer multiple of the reference period IT (step S2). When the vibration frequency f matches one of the plurality of limited command frequencies (YES in step S2), the servo control gain is set to the gain G1. The motor control unit 190 outputs an operation command to the linear servo motor 155 or the like for each reference period (step S3). At each command cycle T corresponding to the command frequency, the operation command matches the most forward position or the most backward position of the vibration frequency f, and this operation command is the same as that output every command cycle T, and depends on the command frequency. With the reciprocating vibration, the cutting tool 130 can process the workpiece W (step S4).

  When the vibration frequency f matches one of the plurality of limited command frequencies, the path of the cutting edge of the cutting tool 130 is the most advanced position of the target waveform at 72 °, as shown by the ♦ mark in FIG. , Reaching the most retracted position at 144 °, reaching the most advanced position at 216 °, reaching the most retracted position at 288 °, and reaching the most advanced position at 360 °. Thus, the path of the cutting edge of the cutting tool 130 connects the most advanced position and the most retracted position of the target waveform.

On the other hand, when the vibration frequency f does not coincide with any of the plurality of limited command frequencies (NO in step S2 in FIG. 6), vibration waveform correction processing is executed (step S5).
Specifically, the control unit 181 selects a target command frequency fc (for example, a value closest to the vibration frequency f among the limited command frequencies), and sets a command cycle T corresponding to the target command frequency fc. Set. The vibration means control unit 191 calls from the gain G2 table 194 and sets the gain G2 to the servo control gain (step S11 in FIG. 7). When the gain G1 for the command frequency fc selected by the control unit 181 has already been set, the gain G2 is changed. The gain G2 is set, for example, to a value lower than the gain G1, and the follow-up response is set to decrease so as to reduce the sensitivity of servo control. Then, the motor control unit 190 outputs an operation command to the linear servo motor 155 or the like for each reference cycle with the position corresponding to the command cycle T of the vibration waveform at the vibration frequency f as a target movement position (step S3 in FIG. 6). ). According to the operation command for each reference cycle, the robot moves toward the target moving position with a change in the moving direction from one predetermined continuous position commanded by the operation command for each reference cycle to the other position, The cutting tool 130 processes the workpiece W with reciprocating vibration along the vibration waveform of the vibration frequency f where the inflection point is located during the period (step S4).

An example of the case where the vibration frequency f does not match any of the plurality of limited command frequencies will be described with reference to FIG. The solid line in FIG. 9 is the waveform of the vibration frequency f, and there is an inflection point at a timing (different main axis phase) different from 72 °, 144 °, 216 °, 288 °, and 360 °.
When moving with the above-described gain G1 in response to the operation command of the mark, in order to move linearly between the adjacent marks ●, the path of the desired cutting edge shown by the broken line is not the path of the cutting edge shown by the solid line It will not be. In the embodiment, the path of the blade edge can be set to a desired vibration frequency by adjusting the servo control gain and setting the follow-up response.

The path of the cutting edge of the cutting tool 130 when the servo control gain is set to the gain G2 and an operation command is issued with a mark ● is shown by a broken line in FIG. The path of the cutting edge of the cutting tool 130 tries to reach a position corresponding to the target waveform at 72 °, but a gain G2 lower than the gain G1 is set and a follow-up delay occurs. The target position is not reached. Since there is a drive delay in the feed mechanism, the path of the cutting edge of the cutting tool 130 moves toward the commanded target position even after passing through 72 °.
When the position for moving to the 72 ° mark is passed, the cutting edge of the cutting tool 130 has moved in the positive direction of the cutting tool position, but in response to the next operation command, the cutting tool position moves to the 144 ° mark. Therefore, it moves with a change of the moving direction so that the inflection point is located during the reference period. Similarly, when an operation command to move to the marks 216 °, 288 °, and 360 ° is output, the path of the cutting edge of the cutting tool 130 moves on the broken line. The frequency of the dashed waveform coincides with the set vibration frequency f. By setting different gains G1 and G2 in the same command cycle T, the cutting tool 130 can be moved at different desired vibration frequencies.

  For example, for the gain G2, a value corresponding to the target vibration frequency f can be experimentally determined in advance and stored in the storage unit 184 as a table for the gain G2.

<Example 2 (correction of vibration amplitude): FIGS.
When the gain G2 is set, the amplitude may be attenuated, for example, as shown by the broken-line vibration waveform in FIG. 9, and a waveform correction unit 192 is provided in the control unit 181 as shown in FIG. The cutting tool 130 can also be configured to move with a vibration waveform having a desired vibration frequency by correcting the attenuation of the amplitude.
Specifically, based on the vibration frequency f that becomes the vibration frequency N with respect to the rotation speed S, the vibration means control unit 191 calls and sets the gain G2 from the gain G2 table 194 (step of FIG. 10). S21). Next, the waveform correction unit 192 acquires a value that compensates the amplitude of the vibration waveform by the gain G2 from the table of the storage unit 184 (step S22). In this table, for example, by storing in advance the reciprocal of the amplitude attenuation rate, the gain G2 is multiplied by the reciprocal of the amplitude attenuation rate, and the amplitude of the target waveform is increased in advance to obtain the amount of amplitude attenuation. The waveform correction unit 192 can be configured to correct (step S23). The waveform correction unit 192 corresponds to the amplitude setting means of the present invention.

For example, in the case of the first embodiment, since the gain G2 is set to a value lower than the gain G1, a cutting edge having a small amplitude as shown by a broken line is shown with respect to the path of the cutting tool 130 shown by a solid line in FIG. Become a route. Here, for ease of explanation, the description will be made assuming that there is no amplitude delay.
In the case of the second embodiment, the vibration of the one-dot chain line obtained by multiplying the amplitude component of the vibration waveform of the vibration frequency f that becomes the vibration frequency N with respect to the rotation speed S by the reciprocal of the attenuation factor of the amplitude generated by the gain G2. An operation command is determined based on the waveform. That is, as shown in FIG. 11, the position indicated by 振動 in the vibration waveform obtained by amplifying the amplitude of the vibration waveform having the vibration frequency f that becomes the vibration frequency N with respect to the rotation speed S is set for each command period T. By setting the target movement position, the cutting tool 130 can move on the cutting edge path indicated by a solid line, which is a vibration waveform having a vibration frequency f such that the vibration frequency N is equal to the rotation speed S. In this way, by correcting the amount of attenuation of the amplitude due to the setting of the gain G2, the overlap between the machining portion during the forward movement and the machining portion during the backward movement is maintained. The amplitude is preferably corrected so that the cutting edge locus of the cutting tool at the time of backward movement reaches the cutting edge locus of the cutting tool at the time of forward movement. However, the amount of amplitude may be such that the cutting edge locus of the cutting tool at the time of backward movement and the cutting edge locus of the cutting tool at the time of forward movement are close enough that the chips generated from the workpiece W are actually divided.

<Example 3 (phase correction): FIGS. 12 and 13>
When the gain G2 is set, for example, as shown in FIG. 9, a phase lag may occur, and the waveform correction unit 192 is used as a phase setting unit in addition to the correction of the amplitude attenuation amount, or the amplitude In addition to correcting the amount of attenuation, it is also possible to correct the phase lag and move the cutting tool 130 with a vibration waveform having a desired vibration frequency.
Specifically, the follow-up adjustment unit 191 calls and sets the gain G2 corresponding to the vibration frequency f that becomes the frequency N with respect to the rotation speed S from the table 194 for the gain G2 (step in FIG. 12). S31). Next, the waveform correction unit 192 acquires values from the table of the storage unit 184 to compensate for the amplitude attenuation amount and phase delay amount of the vibration waveform due to the gain G2 (step S32). In this table, for example, by storing in advance the reciprocal of the attenuation rate of the amplitude and the amount of phase delay, the gain G2 is multiplied by the reciprocal of the attenuation rate, and the amplitude of the target waveform is increased in advance to attenuate the amplitude. The waveform correction unit 192 may be configured to correct the amount (step S33), advance the waveform by the amount of phase delay, and advance the phase of the target waveform in advance to correct the phase delay (step S34). it can.

For example, in the case of the first embodiment, since the gain G2 is set to a value lower than the gain G1, the amplitude of the path of the cutting tool 130 indicated by the solid line in FIG. This is the path where the delay occurred.
In the case of the third embodiment, the vibration waveform obtained by multiplying the amplitude component of the vibration waveform of the vibration frequency f that becomes the vibration frequency N with respect to the rotation speed S by the reciprocal of the attenuation factor of the amplitude generated by the gain G2 is shown in FIG. The phase delay caused by the gain G2 is corrected for the phase component of the vibration waveform at the vibration frequency f that is indicated by the one-dot chain line of FIG. ) The vibration waveform is shown by a two-dot chain line in FIG. By setting the position indicated by □ in the vibration waveform indicated by the two-dot chain line as the target movement position for each command period T, the cutting tool 130 has a vibration frequency N with respect to the rotation speed S. It can move on the path of the vibration frequency f. Thus, if the attenuation amount of the amplitude and the phase delay due to the setting of the gain G2 are compensated for, the cutting tool 130 can achieve the desired cutting edge with the desired vibration frequency even if the servo control sensitivity is dulled. You can move on the route.

In the present embodiment, the phase delay is advanced after multiplying the reciprocal of the attenuation rate. However, the reciprocal of the attenuation rate may be multiplied after the phase delay is advanced.
Further, values such as the amplitude attenuation rate and the phase delay amount may be stored in advance in a table for the gain G2, and the gain, the amplitude attenuation rate, and the phase delay amount may be simultaneously called from the obtained vibration frequency f.
A plurality of gains different from the gain G1 for the command frequency fc may be set. For example, the vibration frequency can be divided into a plurality of sections, and the entire section of the vibration frequency can be covered with a plurality of gains, such as a gain G2 in a predetermined section and a gain G3 in an adjacent section.

DESCRIPTION OF SYMBOLS 100 ... Machine tool 110 ... Spindle 110A ... Spindle 120 ... Chuck 130 ... Cutting tool 130A ... Cutting tool stand 150 ... X-axis direction feed mechanism 151 ... Base 152 ... X-axis direction guide rail 153 ... X-axis direction feed table 154 ... X-axis direction guide 155 ... Linear servo motor 155a ... Movable element 155b ... Stator 160 ... Z-axis Direction feed mechanism 161 ... Base 162 ... Z-axis direction guide rail 163 ... Z-axis direction feed table 164 ... Z-axis direction guide 165 ... Linear servo motor 165a ... Movable element 165b ...・ Stator 180 ・ ・ ・ Control device 181 ・ ・ ・ Control unit 182 ・ ・ ・ Numerical value setting unit 183 ・ ・ ・ Display unit 184 ・ ・ ・ Storage unit 190・ ・ ・ Motor control unit 191 ・ ・ ・ Vibration means control unit 192 ・ ・ ・ Waveform correction unit 194 ・ ・ ・ Table for gain G2

Claims (5)

A workpiece holding means for holding a workpiece, a cutting tool for cutting the workpiece, a rotating means for relatively rotating the workpiece and the cutting tool, and the workpiece holding means or the cutting tool sequentially toward a predetermined position. And moving the workpiece and the cutting tool at a predetermined number of times with respect to the relative rotation, and relatively moving the workpiece holding means and the cutting tool. A machine tool control device for machining the workpiece with the vibration by the vibration means,
The work holding means or the cutting tool with respect to the predetermined position so that the work holding means or the cutting tool moves with a change in the moving direction from one continuous predetermined position side to the other predetermined position side. A machine tool control device comprising a vibration means control unit for setting the follow-up response of the movement of the machine tool.   2. The machine tool control device according to claim 1, wherein the vibration means control unit sets the follow-up response of the movement by setting a servo control gain. 3.   Based on the set gain, it has amplitude setting means for setting the amplitude of the vibration so that the machining part at the time of forward movement and the machining part at the time of backward movement by the vibration means overlap each other. The machine tool control device according to claim 2.   The machine tool control device according to any one of claims 1 to 3, further comprising phase setting means for setting the phase of the vibration based on the set following response. A workpiece holding means for holding a workpiece, a cutting tool for cutting the workpiece, a rotating means for relatively rotating the workpiece and the cutting tool, and the workpiece holding means or the cutting tool sequentially toward a predetermined position. And moving the workpiece and the cutting tool at a predetermined number of times with respect to the relative rotation, and relatively moving the workpiece holding means and the cutting tool. A machine tool that processes the workpiece with the vibration by the vibration means,
The oscillating means holds the workpiece with respect to the predetermined position so that the workpiece holding means or the cutting tool moves from one continuous predetermined position side toward the other predetermined position side in accordance with a change in movement direction. A machine tool in which follow-up response of movement of the means or the cutting tool is set.