JP6799446B2 - Machine tool controls and machine tools - Google Patents

Description

The present invention relates to a machine tool control device and a machine tool.

The heat generated during the cutting process raises the temperature of the cutting tool and workpiece. An increase in the temperature of the cutting tool causes wear of the cutting edge, and an increase in the temperature of the work may affect the machining accuracy of the work. For example, Patent Document 1 discloses a technique of measuring the temperature of a cutting tool to adjust the rotation speed and feed rate of a work.

Japanese Unexamined Patent Publication No. 2014-140951

By the way, in the above-mentioned Patent Document 1, adjustment of cutting conditions according to the temperature of the cutting tool in the case of performing vibration cutting processing such as cutting by vibrating the work with respect to the cutting tool is not considered.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device and a machine tool for a machine tool that performs vibration cutting according to the temperature of a cutting tool.

First, the present invention includes a work holding means for holding a work, a cutting tool for cutting the work, a rotating means for relatively rotating the cutting tool and the work holding means, and the cutting tool. The cutting tool and the work have a vibrating means for relatively reciprocating the work holding means, and the cutting tool and the work are overlapped with each other so that the machined portion during the forward movement and the machined portion during the return movement by the vibrating means overlap. A control device for a machine tool that performs vibration cutting of a workpiece by relatively moving the holding means along a predetermined feed direction, and is based on the temperature of the cutting tool during the forward movement. It is characterized by having a vibration adjusting means for adjusting an overlapping state between the processed portion and the processed portion at the time of recovery.

Secondly, the vibration adjusting means is a non-overlapping period between the processed portion at the time of the forward movement and the processed portion at the time of the return movement, or a non-operation between the processed portion at the time of the forward movement and the processed portion at the time of the return movement. It is characterized by setting an overlapping period.

Thirdly, the vibration adjusting means adjusts the overlapping state so that the temperature of the cutting tool is maintained within a predetermined range.

Fourth, the vibration adjusting means adjusts the overlapping state by setting the amplitude of the reciprocating vibration.

Fifth, the vibration adjusting means adjusts the overlapping state by setting the ratio of the time required for the forward amount and the time required for the backward amount in the reciprocating vibration with respect to the feed direction.

Sixth, the vibration adjusting means is characterized in that the overlapping state is adjusted by setting the frequency of the reciprocating vibration.

Seventh, it is a machine tool provided with a control device for any of the above machine tools.

The present invention can obtain the following effects.
(1) Since the vibration adjusting means can control the calorific value generated in the cutting tool by adjusting the reciprocating vibration condition, specifically, the overlapping state of the machined portion due to the reciprocating vibration based on the temperature of the cutting tool, for example, the efficiency of cutting can be improved. It is possible to perform vibration cutting according to the temperature of the cutting tool, such as being able to suppress the temperature of the cutting portion and perform machining without lowering it.

(2) By making it possible to set the overlapping period between the processed portion at the time of the forward movement and the processed portion at the time of the return movement or the non-overlapping period between the processed portion at the time of the forward movement and the processed portion at the time of the return movement. For example, when the temperature of the cutting tool becomes high, it is possible to set the overlapping period to a longer period than the non-overlapping period and prevent the temperature of the cutting tool from rising during machining.

(3) Since the temperature of the cutting tool can be maintained within a predetermined range by the above, it is possible to adjust the overlapping period and prevent the temperature of the cutting tool from rising during machining.

(4) When the temperature of the cutting tool becomes high, for example, by setting the amplitude to, for example, a large value, the overlapping period between the machined portion during the forward movement and the machined portion during the reverse movement can be extended for a long period of time. It is possible to extend the cooling time of the cutting tool and prevent the temperature of the cutting tool from rising during machining.

(5) When the temperature of the cutting tool becomes high, for example, the time ratio between advancing and retreating is set to a value different from that before the change, and the overlapping period is extended to extend the cooling time of the cutting tool. It is possible to prevent the temperature of the cutting tool from rising during machining.

(6) When the temperature of the cutting tool becomes high, for example, by increasing the frequency, for example, the period during which the machined portion during the forward movement and the machined portion during the reverse movement do not overlap is shortened, and the forward movement is performed. It is possible to promptly start the overlapping period between the machined portion at the time and the machined portion at the time of recovery to prevent the temperature rise of the cutting tool during machining.

(7) It is possible to provide a machine tool capable of performing vibration cutting according to the temperature of a cutting tool.

It is a figure which shows the outline of the machine tool according to one Example of this invention. It is a schematic diagram which shows the relationship between a cutting tool and a work. It is a figure explaining the reciprocating vibration and the position of a cutting tool. It is a figure which shows the relationship of the cutting edge path at each rotation of the nth rotation, n + 1th rotation, and n + 2nd rotation of a spindle. It is a block diagram of a control device. It is a flowchart of the processing process by a control unit. It is a figure explaining the cutting edge path of Example 1. FIG. It is a figure explaining the temperature control by Example 1. FIG. It is a figure explaining the cutting edge path of Example 2. FIG. It is a figure explaining the temperature control by Example 2. FIG. It is a figure explaining the cutting edge path of Example 3. It is a figure explaining the relationship between heat generation and cooling. It is a figure explaining the temperature control by Example 3. FIG.

Hereinafter, the machine tool control device and the machine tool of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the machine tool 100 according to the present invention includes a spindle 110, a cutting tool base 130A, and a control device 180.

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

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 110A is mounted on the Z-axis direction feed table 163. The headstock 110A is arranged so that the axial direction of the spindle 110 coincides with the extending direction of the Z-axis direction guide rail 162.

The linear servomotor 165 has 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 servomotor 165, the headstock 110A moves in the axial direction of the spindle 110 (Z-axis direction in the figure), and the spindle 110 moves. It moves along the Z-axis direction.

The cutting tool base 130A is provided with a cutting tool 130 such as a cutting tool for machining a work W, and constitutes a tool post for holding the cutting tool.
The 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 integrated with the bed side, and an X-axis direction guide rail 152 extending in the X-axis direction orthogonal to the Z-axis direction in the vertical direction. The X-axis direction guide rail 152 is fixed to the base 151, and the 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 servomotor 155 has 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 moves in the X-axis direction along the X-axis direction guide rail 152 by driving the linear servomotor 155, the cutting tool base 130A moves in the X-axis direction, and the cutting tool 130 moves 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 Z-axis direction and the X-axis direction shown in the figure. 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 the drive of the linear servomotor, and the cutting tool base 130A is moved in the X-axis direction. In addition, it can be moved in the Y-axis direction to move the cutting tool 130 in the X-axis direction and 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 base 130A may be mounted on the Y-axis direction feed table.

The rotation of the spindle 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 the Y-axis direction feed mechanism is included in the feed means, and the X-axis direction feed mechanism 150 or the Y-axis direction feed mechanism and the Z-axis direction feed mechanism 160 The headstock 110A and the cutting tool base 130A can be moved to a predetermined position by the cooperation of. 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 motor is moved relative to the spindle 110 and the cutting tool 130. The work W can be machined into a desired shape by driving it as a rotating means to rotate and rotating the work W with respect to the cutting tool 130 as shown in FIG.

In the present embodiment, both the headstock 110A and the cutting tool base 130A can be moved, but 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 configured by a feeding mechanism that moves the cutting tool base 130A. Alternatively, the cutting tool base 130A may be fixed so that the headstock 110A can be moved in the X-axis direction, the Y-axis direction, and the Z-axis direction. In this case, the feeding means is configured by a feeding mechanism provided on the bed.

In the present embodiment, an example in which a linear servomotor is used for the X-axis direction feed mechanism 150 and the Z-axis direction feed mechanism 160 has been described, but a known ball screw and servomotor may be used.
In the present embodiment, the work W is rotated with respect to the cutting tool 130, but a rotating tool such as a drill may be used for the cutting tool 130 to rotate the cutting tool 130 with respect to the work 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) by a predetermined forward amount as shown in FIG. 3 along a predetermined feed direction with respect to the headstock 110A, and then moves a predetermined backward amount. By moving backward (recovery) by the amount, the cutting tool 130 can be sent to the work W by the difference (advance amount) between the forward amount and the backward amount.
The vibrating means is composed of the X-axis direction feed mechanism 150 and the Z-axis direction feed mechanism 160, or the feed means including the Y-axis direction feed mechanism, and moves the headstock 110A and the cutting tool base 130A forward and backward. As a result, the cutting tool 130 can be reciprocally vibrated with respect to the work W.

The cutting tool base 130A is fed along the feeding direction by the feeding means while repeatedly vibrating by the vibrating means, that is, one rotation of the spindle 110, that is, the spindle phase. The total amount of progress during the change from 0 ° to 360 ° is the feed amount.
As the cutting tool 130 repeatedly moves forward and backward along the feed direction to machine the work W, the peripheral surface of the work W is machined into a sinusoidal curve by the cutting tool 130 as shown in FIG. Will be done. FIG. 4 shows an example in which the frequency D of the headstock 110A per rotation of the spindle 110 is 3.5.

The peripheral surface shape of the work W at the n (n is an integer of 1 or more) rotation of the spindle 110 machined by the cutting tool 130 (shown by the solid line in FIG. 4) and the peripheral surface of the work W at the n + 1 rotation of the spindle 110. The shape (shown by a broken line in FIG. 4) deviates from the spindle phase direction (horizontal axis direction in the graph of FIG. 4).
The position of the lowest point of the valley of the peripheral surface shape of the work W shown by the broken line in FIG. 4 (the highest point of the mountain in the cutting tool 130) is the lowest point of the valley of the peripheral surface shape of the work W shown by the solid line in FIG. It does not match the position of (the highest point of the mountain in the cutting tool 130) in the phase direction of the spindle.

As a result, the cutting tool locus of the cutting tool 130 overlaps the cutting part at the time of this forward movement and the cutting part at the time of the next return movement, and for example, the peripheral surface shape of the work W at the n + 1th rotation of the spindle 110. Since the peripheral surface shape of the work W at the nth rotation of the spindle 110 is included, the cutting tool 130 causes an idle swing operation without processing the work W. The chips generated from the work W are separated during this idle swing operation due to the overlapping period between the processed portion during the forward movement and the processed portion during the reverse movement. The machine tool 100 processes the outer shape of the work W while dividing the chips, and the cutting tool 130 processes the work W in a non-overlapping period in which the machined portion during the forward movement and the machined portion during the reverse movement do not overlap. Perform processing (cutting).

The frequency D of the cutting tool base 130A (cutting tool 130) per rotation of the spindle 110 (work W) can be, for example, 1.1 or 1.25 times, and is set to a value smaller than one time. You can also do it. When the frequency D is set to a value smaller than one time, the spindle 110 rotates more than one rotation by the time the cutting tool base 130A makes one reciprocation. The frequency D can also be set as the rotation speed of the spindle 110 per vibration.

As shown in FIG. 5, the control device 180 includes a control unit 181, a temperature detection unit 182, and a storage unit 184, which are connected via a bus.
The control unit 181 is composed of a CPU or the like, and includes a motor control unit 190 that controls the operation of each of the motors and a vibration adjustment unit 191 that controls the operation of the vibration means to adjust the vibration. The control unit 181 loads various programs and data stored in, for example, a ROM of the storage unit 184 into the RAM, and executes the various programs. As a result, the motor control unit 190 and the vibration adjustment unit 191 are based on the programs. The operation of the machine tool 100 can be controlled via the above.

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

When the command cycle T is, for example, 16 (ms), which is four times the reference cycle 4 (ms), the motor control unit 190 causes the cutting tool 130 to reciprocate 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 reciprocates at a command frequency fc = 1 / T = 1 ÷ (0.004 × 4) = 62.5 (Hz) due to the command cycle T = 16 (ms).

Assuming that the rotation speed of the spindle 110 is S (r / min), the frequency of the cutting tool 130 with respect to the rotation of the work W is D (times / r), and the vibration frequency of the cutting tool 130 with respect to the work W is f (Hz), the frequency is D is D = f × 60 / S. The rotation speed S and the frequency D are inversely proportional to each other with the vibration frequency f as a constant, and the spindle 110 can rotate at a high speed as the vibration frequency f increases, and rotates at a high speed as the frequency D decreases. it can.

The control unit 181 rotates the spindle 110 at the rotation speed S and sends the cutting tool 130 in the feed direction while vibrating at the frequency D in order to process the work W into a predetermined shape. The motor control unit 190 outputs an operation command to the linear servomotor 155 and the like for each reference cycle IT, and the headstock 110A or the cutting tool base 130A moves following the coordinate position in which the operation command is given. The cutting tool 130 can be vibrated at the command frequency fc.

In the control device 180, as shown in FIG. 6, when machining is started (step S1), the control unit 181 sets the temperature T of the tip (cutting edge) of the cutting tool 130 based on the output of the temperature detection unit 182. Calculate (step S2).
The temperature detection unit 182 can be configured by a thermocouple attached near the cutting edge, an infrared detection element, or the like. When the control unit 181 calculates the temperature T, whether or not the temperature maintenance control of the cutting tool 130 is performed from the calculated temperature T is determined by, for example, comparing the set value which is the threshold value stored in the storage unit 184 with the temperature T. Determine (step S3).

The set value can be in a temperature range such as 150 ° C. to 200 ° C. In addition, the set value can be set to the upper limit temperature or the lower limit temperature, or can be specified by the rate of change with respect to the predetermined temperature so as to be "+ 40% change from the initial temperature" or "-10% change from the saturation temperature". It can also be in the range of the rate of change, such as "-10% to + 20%" with respect to a predetermined temperature. It can be a pre-calculated average temperature at the time of machining, or an increase rate from the start of non-cutting. The set value can be set by, for example, an operator of a machine tool via an input unit such as a keyboard.

For example, when the set value is set as the upper limit temperature, the temperature T of the cutting edge becomes equal to or higher than the set value, and it is determined that temperature maintenance control is necessary (YES in step S3), the temperature of the cutting edge is within a predetermined range by the vibration adjusting unit 191. The overlapping state and non-overlapping period of the processed part at the time of the forward movement and the processed part at the time of the reverse movement are set so as to be maintained at, and the processed part at the time of the forward movement and the processed part at the time of the reverse movement are set. The overlapping state is adjusted (step S4), the process returns to step S1, and the cutting process is continued in the newly adjusted overlapping state.
The vibration adjusting unit 191 corresponds to the vibration adjusting means of the present invention.
When it is determined in step S3 that the temperature maintenance control is unnecessary (NO in step S3), the end of machining is checked (step S5), the process returns to step S2 if the machining is not completed, and the flow is performed when the machining is completed. finish.

In the non-overlapping period, the work W and the cutting tool 130 come into contact with each other in the feeding direction to perform the cutting process, so that frictional heat is generated due to the cutting and the temperature of the cutting edge of the cutting tool 130 rises. On the other hand, in the overlapping period, since the work W and the cutting tool 130 do not come into contact with each other in the feed direction, the heat generated in the cutting tool 130 is dissipated and the temperature of the cutting edge drops. The amount of heat generated in the cutting tool 130 can be controlled based on the heat dissipation during the overlapping period and the temperature rise of the cutting edge during the non-overlapping period.
The vibration conditions can be set so that the overlapping period or the non-overlapping period becomes a predetermined predetermined period.

The overlapping period and the non-overlapping period can be set by adjusting the amplitude in the reciprocating vibration by the vibration adjusting unit 191 as shown in FIGS. 7 and 8. The amplitude can be determined, for example, by multiplying the feed amount by a predetermined amplitude feed ratio Q. In this case, the amplitude can be adjusted by changing the setting of the amplitude feed ratio Q. The amplitude feed ratio Q can be set by describing the value of the amplitude feed ratio Q in the machining program.
For example, when the temperature T of the cutting edge exceeds the set value, the value of the amplitude feed ratio Q is increased to extend the overlap period and shorten the non-overlap period as compared with before the change of the amplitude feed ratio Q. can do.

In FIG. 7, the cutting edge path of the nth rotation of the spindle 110 is shown by a solid line, the cutting edge path of the n + 1th rotation of the spindle 110 is shown by a broken line, and the cutting edge path of the n + 2nd rotation of the spindle 110 is shown by a chain line (A). duplicate ~ (C) are each the amplitude feed ratio Q respectively 2.0, 3.0, 4.0, the overlap period when the Q = 2.0 at _{O a,} when Q = 3.0 the period _{O B,} depicts the overlap period when Q = 4.0 at _{O C.}

As shown in FIG. 7, the overlap period _is, O _A, O B, increases in the order of _{O C (O A <O B} <O C), the heat dissipation is the duration of the cutting edge (release according to increase the amplitude feed ratio Q The amount of heat) can be increased.
For example, the set values set a first threshold value for changing the amplitude feed ratio Q from 2.0 to 3.0 and a second threshold value for changing the amplitude feed ratio Q from 3.0 to 4.0. As shown in FIG. 8, when the temperature T of the cutting edge reaches the first threshold value, the amplitude feed ratio Q is set to 3.0 to suppress an increase in the temperature of the cutting edge. When the temperature T of the cutting edge reaches the second threshold value, the amplitude feed ratio Q is set to 4.0, and the temperature of the cutting edge can be substantially maintained.

By changing the amplitude feed ratio Q based on the temperature T of the cutting tool 130 and adjusting the overlapping period or the non-overlapping period, the temperature of the cutting edge of the cutting tool 130 is maintained in a predetermined temperature range for vibration cutting. It can be carried out.
The amplitude feed ratio Q can be automatically changed and set each time the temperature T of the cutting edge exceeds the first threshold value or the second threshold value.
In addition to increasing the amplitude feed ratio Q in increments of 1.0, the rate of change of the amplitude feed ratio Q can be set by increasing it by 20% with respect to a predetermined value, or a calculation formula or table is provided in advance. It is also possible to obtain and set a predetermined amplitude feed ratio Q from the table.

As shown in FIGS. 9 and 10, the overlapping period and the non-overlapping period can be set by adjusting the ratio of the amount of retreat in one vibration of the reciprocating vibration (forward / backward ratio K) by the vibration adjusting unit 191. The ratio of the retreat amount can be determined, for example, by the ratio of the time required for the advance amount and the time required for the retreat amount with respect to the feed direction of the reciprocating vibration. The forward / backward ratio K can be set by describing the value of the forward / backward ratio K in the machining program.
For example, when the temperature T of the cutting edge exceeds the set value, the value of the forward / backward ratio K is increased to extend the overlapping period and shorten the non-overlapping period as compared with before the change of the forward / backward ratio K. can do.

In FIG. 9, the cutting edge path of the nth rotation of the spindle 110 is shown by a solid line, the cutting edge path of the n + 1th rotation of the spindle 110 is shown by a broken line, and the cutting edge path of the n + 2nd rotation of the spindle 110 is shown by a chain line (A). , (B) are each a forward and backward ratio K respectively and 0.5,0.9, the overlap period when the K = 0.5 at _{O D,} the overlap period when the K = 0.9 _{O E} Indicated by.

As shown in FIG. 9, the overlap period _{is, O} D, increases in the order of _{O E (O D <O E} ), to increase the period (heat radiation amount) is radiated in the cutting edge in accordance with increasing the forward and backward ratio K it can.
For example, a first threshold (upper limit temperature) for changing the forward / backward ratio K from 0.5 to 0.9 and a second threshold for changing the forward / backward ratio K from 0.9 to 0.5. When (lower limit temperature) is set as the set value, as shown in FIG. 10, when the temperature T of the cutting edge reaches the first threshold value, the forward / backward ratio K is set to 0.9 as a vibration condition. When the temperature rise of the cutting edge is suppressed and the temperature T of the cutting edge reaches the second threshold value, the forward / backward ratio K is set to 0.5, and the temperature falling of the cutting edge is suppressed.

After that, the temperature of the cutting edge can be kept within a predetermined range by changing the forward / backward ratio K every time the temperature T of the cutting edge reaches the first threshold value or the second threshold value.
By changing the forward / backward ratio K based on the temperature T of the cutting tool 130 and adjusting the overlapping period or the non-overlapping period, the temperature of the cutting edge of the cutting tool 130 is maintained within a predetermined temperature range for vibration cutting. It can be carried out.

The forward / backward ratio K can be automatically changed and set each time the temperature T of the cutting edge exceeds the first threshold value or the second threshold value. It is also possible to set the forward / backward ratio K that can maintain the temperature of the cutting edge at a predetermined temperature, and then continue the vibration cutting process with the forward / backward ratio K.

The overlapping period and the non-overlapping period can be set by adjusting the frequency D of the reciprocating vibration by the vibration adjusting unit 191 as shown in FIGS. 11, 12, and 13. The frequency D can be set by describing the rotation speed S of the spindle 110 and the value of the vibration frequency f of the cutting tool 130 with respect to the work W in the machining program.
For example, when the temperature T of the cutting edge exceeds the set value, the value of the frequency D is increased to increase the number of overlapping / non-overlapping states as compared with before the frequency D is changed, and the non-overlapping state is increased. The period can be shortened.

In FIG. 11, the cutting edge path of the nth rotation of the spindle 110 is shown by a solid line, the cutting edge path of the n + 1th rotation of the spindle 110 is shown by a broken line, and the cutting edge path of the n + 2nd rotation of the spindle 110 is shown by a chain line (A). , (B) are each a frequency D respectively with 0.5, 1.5, the non-overlapping period of time of D = 0.5 at _{Q F,} the non-overlapping period of time of D = 1.5 Q Indicated by _G.

As shown in FIG. 11, the non-overlapping period increases in the order of Q _G and Q _F (Q _G <Q _F ), and as the frequency D increases, the chance of heat dissipation of the cutting edge increases and the amount of heat radiation increases. Can be made to. At the frequency D = 0.5 shown by the solid line in FIG. 12, heat is dissipated in an overlapping period after the temperature of the cutting edge is almost saturated. At the frequency D = 1.5 shown by the broken line in FIG. 12, heat is dissipated in an overlapping period before the temperature of the cutting edge is saturated.
Therefore, when comparing the temperature of the cutting edge at the time of one vibration at the frequency D = 0.5 and the temperature of the cutting edge at the time of three vibrations at the frequency D = 1.5 in two rotations of the spindle 110, the vibration The number D = 1.5 is lower by Δt.

For example, when a threshold value (upper limit temperature) for changing the frequency D from 0.5 to 1.5 is set as the set value, the temperature T of the cutting edge is the threshold value as the vibration condition as shown in FIG. When it reaches, the frequency D is set to 1.5, and the temperature of the cutting edge can be generally maintained.
By changing the frequency D based on the temperature T of the cutting tool 130 and adjusting the overlapping period or the non-overlapping period, the temperature of the cutting edge of the cutting tool 130 is maintained in a predetermined temperature range to perform vibration cutting. be able to. By providing a plurality of threshold values, the frequency D can be configured to be automatically changed and set each time the temperature T of the cutting edge exceeds each threshold value.

The amplitude feed ratio Q, the forward / backward ratio K, and the frequency D are used as parameters for adjusting the overlapping state between the processed portion at the time of forward movement and the processed portion at the time of reverse movement to adjust the overlapping period and the non-overlapping period. , The setting of the amplitude feed ratio Q described in the examples of FIGS. 7 and 8, the setting of the forward / backward ratio K described in the examples of FIGS. 9 and 10, and the vibration described in the examples of FIGS. 11, 12, and 13. It is also possible to combine the settings of the number D.
For example, a parameter to be prioritized is determined in advance, a worker or the like inputs the priority of the parameter into a program or the like, and each time the adjustment range of each parameter is exceeded, the value of each parameter is changed in order of priority. be able to.
Further, the priority parameter may be automatically set according to each combination pattern of the work W material and the cutting tool material type.

If the parameter value is changed during the execution of machining corresponding to a predetermined program block, it is possible that the machining part at the time of forward movement and the machining part at the time of recovery do not sufficiently overlap immediately after the change. The parameter values may be changed for each program block or for each machining cycle.
After the parameter value is changed, the machining can be continuously executed according to the changed parameter value for a predetermined period.

100 ・ ・ ・ Machine machine 110 ・ ・ ・ Main shaft 110A ・ ・ ・ Headstock 120 ・ ・ ・ Chuck 130 ・ ・ ・ Cutting tool 130A ・ ・ ・ Cutting tool base 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 servomotor 155a ・ ・ ・ Movable element 155b ・ ・ ・ Controller 160 ・ ・ ・ Z-axis Directional feed mechanism 161 ・ ・ ・ Base 162 ・ ・ ・ Z-axis direction guide rail 163 ・ ・ ・ Z-axis direction feed table 164 ・ ・ ・ Z-axis direction guide 165 ・ ・ ・ Linear servomotor 165a ・ ・ ・ Mover 165b ・ ・ ・・ Controller 180 ・ ・ ・ Control device 181 ・ ・ ・ Control unit 182 ・ ・ ・ Temperature detection unit 184 ・ ・ ・ Storage unit 190 ・ ・ ・ Motor control unit 191 ・ ・ ・ Vibration adjustment unit

Claims (7)

The work holding means for holding the work, the cutting tool for cutting the work, the rotating means for relatively rotating the cutting tool and the work holding means, and the cutting tool and the work holding means are relative to each other. The cutting tool and the work holding means are fed in a predetermined feed direction so as to have a vibrating means for reciprocating and reciprocating the cutting tool so that the machined portion during the forward movement and the machined portion during the return movement by the vibrating means overlap. It is a control device of a machine tool that performs vibration cutting of the work by moving it relatively along the above.
A machine tool control device having a vibration adjusting means for adjusting an overlapping state between a machined portion during forward movement and a machined portion during reverse movement based on the temperature of the cutting tool. The vibration adjusting means sets an overlapping period between the processed portion at the time of the forward movement and the processed portion at the time of the return movement, or a non-overlapping period between the processed portion at the time of the forward movement and the processed portion at the time of the return movement. The machine tool control device according to claim 1. The machine tool control device according to claim 1 or 2, wherein the vibration adjusting means adjusts the overlapping state so that the temperature of the cutting tool is maintained within a predetermined range. The machine tool control device according to any one of claims 1 to 3, wherein the vibration adjusting means adjusts the overlapping state by setting the amplitude of the reciprocating vibration. Any one of claims 1 to 4, wherein the vibration adjusting means adjusts the overlapping state by setting a ratio of a time required for a forward amount and a time required for a backward amount in the reciprocating vibration with respect to the feed direction. The machine tool control device described in. The machine tool control device according to any one of claims 1 to 5, wherein the vibration adjusting means adjusts the overlapping state by setting the frequency of the reciprocating vibration. A machine tool provided with the control device for the machine tool according to any one of claims 1 to 6.