JP2020013355A - Control device of machine tool and machine tool - Google Patents

Abstract

To provide a control device of a machine tool and the machine tool reducing shaking of entire bed when vibration cutting.SOLUTION: A control device of a machine tool comprises on a same bed 11: one rotation means relatively rotating a workpiece W1 and a cutting tool 130; one vibration means relatively vibrating the workpiece and the cutting tool; the other rotation means relatively rotating a workpiece W2 and a cutting tool 230; and the other vibration means relatively vibrating the workpiece and the cutting tool. During cutting of the workpiece W1, the cutting of the workpiece is performed so that cutting edge paths of the cutting tool are overlapped, operation of the other vibration means is controlled so that vibration reducing shaking of the entire bed due to the cutting of the workpiece is generated, and the number of rotation by the other rotation means rotating the workpiece W2 and the cutting tool 230 is set to the number of rotation for generating the overlap of the cutting edge paths of the cutting tool, to perform vibration cutting of the workpiece.SELECTED DRAWING: Figure 1

Description

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

  Conventionally, a cutting tool for cutting a work, a rotating means for relatively rotating the work and the cutting tool, and a vibration means for vibrating the work and the cutting tool at a predetermined number of vibrations relative to the relative rotation provided By sending the cutting tool to the work while causing the work and the cutting tool to vibrate at a predetermined vibration frequency by the vibrating means, a cutting process (vibration cutting) of processing the work by the cutting tool with vibration is performed. There is known a machine tool capable of performing such operations (for example, Patent Document 1).

WO 2015/146946

  When a work and a cutting tool are installed on a bed of a machine tool and vibration cutting is performed at a predetermined vibration frequency, the entire bed may shake. Since this sway may cause a reduction in machining accuracy and noise around the machine tool, it is desirable to suppress the sway of the entire bed.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a machine tool control device and a machine tool that suppress the swing of the entire bed when performing vibration cutting.

  The present invention firstly provides one rotating means for relatively rotating one work and one cutting tool, and one vibrating means for relatively vibrating the one work and the one cutting tool. And the other rotating means configured separately from the one rotating means, the other rotating means for relatively rotating the other work and the other cutting tool, and the one vibrating means are separately configured and the other rotating means. A control device for a machine tool, wherein a work and another vibrating means for relatively vibrating the other cutting tool are installed on the same bed, wherein the one cutting tool cuts the one work. At this time, the relative rotation of the one cutting tool in a predetermined machining feed direction accompanied by the vibration of the one vibration means and the relative rotation by the one rotating means are controlled, and the one cutting operation is performed. Tool edge path weight So that the cutting of the one work is performed, and the operation of the other vibrating means is controlled so as to generate vibration that suppresses vibration of the entire bed caused by the cutting of the one work. The other work and the other cutting tool are relatively transmitted in a predetermined machining feed direction with the vibration of the other vibrating means, and the number of revolutions of the other rotating means is changed to the cutting edge of the other cutting tool. It is characterized in that cutting of the other work is performed by setting so that overlapping of paths occurs.

  Secondly, there is a machine tool provided with the above machine tool control device.

The present invention can obtain the following effects.
(1) When the other vibrating means vibrates at the time of vibrating cutting with one cutting tool by one vibrating means, it is possible to suppress the swing of the entire bed. By performing the vibration cutting by the other cutting tool by the vibration of the other vibration means, the vibration of the entire bed can be suppressed, and the vibration cutting of each work can be performed by both the cutting tools.

(2) It is possible to provide a machine tool capable of easily suppressing the entire bed from shaking.

It is a figure showing the outline of the machine tool by one example of the present invention. It is a block diagram of a control apparatus. It is a figure explaining reciprocation and position of a cutting tool. It is a figure which shows the cutting-edge path | route of the nth rotation of a main shaft, the n + 1st rotation, and the n + 2 rotation. FIG. 4 is a diagram illustrating a relationship between a command cycle and a vibration frequency. It is a figure which shows the relationship between the frequency | count of a vibration, a main shaft rotation speed, and a vibration frequency.

  Hereinafter, a machine tool control device and a machine tool according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, a front spindle 110 is installed on a bed 11.
A chuck 120 is provided at the tip of the front spindle 110, and one workpiece W1 is gripped and held by the front spindle 110 via the chuck 120. The front spindle 110 is rotatably supported by the front spindle head 110A, and is rotated and driven by the power of a spindle motor (for example, a built-in motor) provided between the front spindle head 110A and the front spindle 110, for example. The front headstock 110A is mounted on the bed 11 via a Z-axis direction feed mechanism 160.

  The Z-axis direction feed mechanism 160 includes a base 161 integrated with the bed 11 and a Z-axis direction guide rail 162 that slidably supports the Z-axis direction feed table 163. When the Z-axis direction feed table 163 moves along the illustrated Z-axis direction that coincides with the rotation axis direction of the work W1 by driving the linear servo motor 165, the front headstock 110A moves in the Z-axis direction. The linear servo motor 165 has a mover 165a and a stator 165b. The mover 165a is provided on a Z-axis direction feed table 163, and the stator 165b is provided on a base 161.

One cutting tool 130 such as a cutting tool for processing the work W1 is mounted on a front tool table 130A, and the front tool table 130A is mounted on the bed 11 via an X-axis feed mechanism 150.
The X-axis direction feed mechanism 150 includes a base 151 integrated with the bed 11 and an X-axis direction guide rail 152 that slidably supports the X-axis direction feed table 153. When the X-axis direction feed table 153 moves along the X-axis direction orthogonal to the Z-axis direction shown by the drive of the linear servomotor 155, the front tool table 130A moves in the X-axis direction. The linear servomotor 155 includes a mover 155a and a stator 155b. The mover 155a is provided on an X-axis direction feed table 153, and the stator 155b is provided on a base 151.

The back spindle 210 is installed on the same bed 11.
A chuck 220 is provided at the tip of the back spindle 210, and the other work W2 is gripped and held by the back spindle 210 via the chuck 220. The back spindle 210 is rotatably supported by the back spindle head 210A, and is driven to rotate by the power of a spindle motor (for example, a built-in motor) provided between the back spindle head 210A and the back spindle 210, for example. The rear headstock 210A is mounted on the bed 11 via a Z-axis direction feed mechanism 260.

  The Z-axis direction feed mechanism 260 includes a base 261 integrated with the bed 11 and a Z-axis direction guide rail 262 that slidably supports the Z-axis direction feed table 263. When the Z-axis direction feed table 263 moves along the illustrated Z-axis direction by driving the linear servomotor 265, the rear headstock 210A moves in the Z-axis direction. The linear servo motor 265 has a mover 265a and a stator 265b. The mover 265a is provided on a Z-axis direction feed table 263, and the stator 265b is provided on a base 261.

The other cutting tool 230 such as a cutting tool for processing the work W2 is mounted on the back tool table 230A, and the back tool table 230A is mounted on the bed 11 via the X-axis direction feed mechanism 250.
The X-axis direction feed mechanism 250 includes a base 251 integrated with the bed 11 and an X-axis direction guide rail 252 that slidably supports the X-axis direction feed table 253. When the X-axis direction feed table 253 moves along the illustrated X-axis direction by driving the linear servomotor 255, the rear headstock 210A moves in the X-axis direction. The linear servomotor 255 has a mover 255a and a stator 255b. The mover 255a is provided on an X-axis direction feed table 253, and the stator 255b is provided on a base 251.

The machine tool 10 may be provided with a Y-axis direction feed mechanism. The Y-axis direction is orthogonal to the illustrated Z-axis direction and X-axis direction. The Y-axis direction feed mechanism may have the same structure as the Z-axis direction feed mechanisms 160 and 260 or the X-axis direction feed mechanisms 150 and 250. As conventionally known, the combination of the X-axis feed mechanisms 150 and 250 and the Y-axis feed mechanism allows the cutting tools 130 and 230 to be moved in the Y-axis direction in addition to the X-axis direction.
Although the Z-axis feed mechanisms 160 and 260, the X-axis feed mechanisms 150 and 250, and the Y-axis feed mechanism have been described using examples using a linear servomotor, they have a structure using a known ball screw and servomotor. Is also good.

The rotation of the front main shaft 110 and the rear main shaft 210 and the movement of the Z-axis direction feed mechanisms 160 and 260 are controlled by the control device 180.
As shown in FIG. 2, the control device 180 includes a control unit 181, a numerical value setting unit 182, and a storage unit 183, which are connected via a bus.
The control unit 181 includes a CPU or the like, loads various programs and data stored in, for example, the ROM of the storage unit 183 into the RAM, and executes the programs. Thereby, the operation of the machine tool 10 can be controlled based on a predetermined program.

The control unit 181 can control the rotation of the front main shaft 110 and the rear main shaft 210 and the feed of the Z-axis direction feed mechanisms 160 and 260, and has a motor control unit 190 that controls the operation of each motor.
The control unit 181 drives the spindle motor to rotate the front spindle 110, thereby rotating the work W1 with respect to the cutting tool 130, and driving the Z-axis feed mechanism 160 to cut the work W1. The tool 130 is moved in the Z axis direction, and the X axis direction feed mechanism 150 is driven to move the cutting tool 130 in the X axis direction with respect to the workpiece W1. The relative movement between the cutting tool 130 and the work W1 allows the cutting tool 130 to be sent in a predetermined machining feed direction, and the work W1 to be machined by the cutting tool 130.

  As shown in FIG. 3, the control unit 181 moves the cutting tool 130 with respect to the workpiece W1 by a predetermined amount of forward movement along the machining feed direction (forward movement), and then moves (reverses) by a predetermined amount of retreat. ), The Z-axis feed mechanism 160 or the X-axis feed mechanism 150 is moved and driven. The control unit 181 reciprocates and vibrates the cutting tool 130 by the movement of the front headstock 110A or the front tool table 130A by the movement drive of the Z-axis direction feed mechanism 160 or the X-axis direction feed mechanism 150, and the amount of advance and retreat It can be sent to the work W1 by the difference (the amount of progress) from the amount. When the outer circumference of the work W1 is cut by the cutting tool 130, the circumferential surface of the work W1 is processed into a wavy shape.

  When the cutting tool 130 starts machining the work W1 at the position of the main shaft phase 0 °, the total amount of the above-mentioned progress during the change from the main shaft phase 0 ° corresponding to one rotation of the work W1 to 360 ° is the feed of the cutting tool 130. Amount. FIG. 4 shows an example in which the number of reciprocating movements of the cutting tool 130 in one rotation of the workpiece W1 is the number of vibrations D1, and the number of vibrations D1 is 3.5 (times / r). An imaginary line (dashed-dotted line) passing through the valley of the wavy waveform is a feed straight line indicating the feed amount, and the position of the main shaft phase of 360 ° in the feed straight line corresponds to the feed amount F per rotation of the work W1. I do.

Since the number of vibrations D1 is different from an integer, the cutting edge path of the cutting tool 130 at the nth rotation of the front spindle 110 (work W1) (shown by a solid line in FIG. 4) and the cutting edge path at the (n + 1) th rotation (shown by a broken line in FIG. 4). ) Deviates in the main shaft phase direction (horizontal axis direction of the graph in FIG. 4), and the cutting edge path of the cutting tool 130 is overlapped during cutting.
During the overlap period in which the cutting edge path of the (n + 1) th rotation is included in the cutting edge path of the nth rotation, the cutting tool 130 and the workpiece W1 do not contact in the processing feed direction because the cutting has already been performed by the processing of the nth rotation. The idle period in which the tool 130 does not substantially cut the work W1 is reached, and the chips generated in the work W1 are divided into chips. By vibrating the workpiece W1 with the cutting tool 130 while vibrating due to the reciprocating movement of the cutting tool 130 with respect to the workpiece W1, the workpiece W1 can be smoothly processed while cutting chips.

  The control unit 181 moves the cutting tool 230 (forward movement) with respect to the workpiece W2 along the machining feed direction by a predetermined amount of forward movement on the side of the rear main shaft 210, and then retreats by a predetermined amount. The Z-axis feed mechanism 260 or the X-axis feed mechanism 250 is driven to move (return) by an amount, and the cutting tool 230 is reciprocated by the movement of the back headstock 210A or the back tool stand 230A to vibrate. Then, only the difference between the amount of advance and the amount of retreat (the amount of advance) can be sent to the workpiece W2. The controller 181 rotates the work W2 at the spindle rotation speed R2, and reciprocates and vibrates the cutting tool 230 at the number of vibrations D2 to cause a difference between the amount of advance and the amount of retreat along the machining feed direction (the amount of advance). By only feeding, the workpiece W2 can be subjected to vibration cutting while cutting chips generated in the workpiece W2.

The vibration of the entire bed 11 may be generated by performing the vibration cutting by reciprocating the cutting tool 130 in the processing feed direction while rotating the work W1 on the front main shaft 110.
In this case, the control unit 181 calculates the vibration frequency f2 that suppresses the vibration of the entire bed 11 and sets the vibration frequency f2 of the vibration caused by the reciprocating movement of the cutting tool 230 with respect to the work W2 on the back spindle 210 side.

Specifically, the control unit 181 rotates the work W2 with respect to the cutting tool 230, and moves the cutting tool 230 in the machining feed direction with the vibration caused by the reciprocal movement. , A parameter calculation unit 192, and a processing execution unit 193.
When the vibration frequency f1 of the vibration due to the reciprocating movement of the cutting tool 130 with respect to the front main shaft 110 is, for example, 50 (Hz), and when the entire bed 11 is vibrated, the rear main shaft 210 is set to the opposite phase of, for example, 50 (Hz). In the case where the vibration of the entire bed 11 can be suppressed by vibrating, the vibration condition calculation unit 191 calculates the vibration frequency f2 as 50 (Hz) as the vibration condition for suppressing the vibration of the entire bed 11.

  Note that the vibration generated in the entire bed 11 can use a known configuration such as measurement with a vibrometer installed in the bed 11, for example. The vibration frequency f2 is determined by the size and weight of the front headstock 110A including the front spindle 110 and the front toolrest 130A including the cutting tool 130, the rear toolhead 210A including the rear spindle 210, and the rear toolrest 230A including the cutting tool 230. In addition to being able to calculate by calculation according to the size and weight, a plurality of vibration frequencies f2 corresponding to the frequency of the bed 11 can be stored in the storage unit 183 as a table.

The parameter calculation unit 192 calculates the main shaft rotation speed R2 of the back main shaft 210 and the number of vibrations D2 of the cutting tool 230 based on the vibration frequency f2 obtained by the vibration condition calculation unit 191.
The processing execution unit 193 moves and drives the Z-axis direction feed mechanism 260 or the X-axis direction feed mechanism 250, for example, when the cutting tool 230 is vibrated at 50 (Hz) having an opposite phase to the cutting tool 130, The back headstock 210A or the back tool stand 230A is reciprocated to vibrate. When the number of vibrations D2, which is the number of reciprocating movements of the cutting tool 230 in one rotation of the work W2, is set to 1.5, the main shaft rotation speed R2 of the back main shaft 210 is set to 2000 (r / min), and the work W2 is set. By rotating the cutting tool 230, the cutting tool 230 is reciprocated at a vibration frequency D2 of (1.5), and is sent in a predetermined machining feed direction. The work W2 can be subjected to vibration cutting while cutting chips generated in W2.

Even if vibration of the entire bed 11 occurs due to vibration cutting processing involving vibration due to reciprocal movement in the front main spindle 110, the rear main spindle 210 vibrates based on the vibration frequency f2 at which vibration of the entire bed 11 can be suppressed. 11 can be suppressed.
In addition, the machining is performed on the front spindle 110 side and the rear spindle 210 side with vibrations so that the cutting edge paths overlap the workpieces W1 and W2, thereby suppressing the entire bed 11 from swaying and both. Vibration cutting with vibration caused by reciprocating movement of the cutting tools 130 and 230 can be performed.

  When it is possible for the control unit 181 to send, for example, 250 operation commands per second, the operation command to the Z-axis direction feed mechanisms 160 and 260 or the X-axis direction feed mechanisms 150 and 160 is 1 ÷ 250 = Output can be performed at a period of 4 (ms) (also referred to as a reference period IT). Generally, the command cycle T is an integral multiple of the reference cycle.

If the command cycle T is 16 (ms), which is, for example, four times the reference cycle 4 (ms), the motor control unit 190 causes the cutting tool 130 to reciprocate every 16 (ms). A drive signal can be output to the axial feed mechanism 160. In this case, as shown in FIG. 5, the cutting tool 130 can reciprocate at the vibration frequency f = 1 / T = 1 ÷ (0.004 × 4) = 62.5 (Hz).
The command cycle T is, for example, 20 times (ms) of 5 times, 24 times (ms) of 6 times, 28 times (ms) of 7 times, and 32 times (ms) of 8 times of the reference cycle IT. it can. In this case, the vibration frequency f = 1 ÷ (0.004 × 5) = 50 (Hz), 1 ÷ (0.004 × 6) = 41.666 (Hz), 1 ÷ (0.004 × 7) = 35 .714 (Hz), 1 ÷ (0.004 × 8) = 31.25 (Hz) can be used to reciprocate the cutting tool 130. Thus, the vibration frequency for reciprocating the cutting tool 130 is selected from these usable limited values.

The spindle rotation speed R, the number of vibrations D of the cutting tool in one rotation of the workpiece W, and the vibration frequency f for reciprocating the cutting tool can be set by a machining program or by inputting to the numerical value setting unit 182. Assuming that the spindle rotation speed is R (r / min), the number of vibrations is D (times / r), and the vibration frequency is f (times / sec), the number of vibrations D is D = f × 60 / R.
As shown in FIG. 6, the main shaft rotation speed R and the vibration frequency D are in inverse proportion with the vibration frequency f as a constant. For this reason, the spindle frequency R can be increased as the vibration frequency f is increased, and the work W rotates at high speed. In addition, as the number of vibrations D decreases, the spindle rotation speed R can be increased, and the work W rotates at high speed.

  When the workpiece W is rotated at the spindle rotation speed R and the cutting tool is reciprocated at the vibration frequency D, the vibration frequency f such that the vibration frequency D becomes the vibration frequency D with respect to the spindle rotation speed R is a limited value that can be used. If the value matches any of the above, this value is set to the target vibration frequency. The motor control unit 190 outputs an operation command to the linear servomotor 155 and the like for each reference cycle, and can reciprocate the cutting tool at the set vibration frequency f.

The spindle rotation speed R2 or the number of vibrations D2 can be set by setting the spindle rotation speed R2 or the number of vibrations D2 of the cutting tool 230 in one rotation of the workpiece W2 by a machining program or by inputting to the numerical value setting unit 182. Alternatively, machining can be performed at a spindle speed or vibration frequency relatively close to the spindle speed R2 or vibration frequency D2.
If the vibration frequency f2 set on the back main shaft 210 does not match any of the usable limited values, the vibration frequency f2 is set to a relatively close value among the usable limited values. be able to.
If the user sets the spindle speed R2 = 3000 (r / min) and the number of vibrations D2 = 1.5 (times / r), f = 1.5 × 3000/60 = 75 (Hz). Therefore, as the vibration frequency f2, 62.5 (Hz), which is the closest to 75 (Hz), is selected from the available limited value. The spindle rotation speed R2 and the vibration frequency D2 can be set to values close to the set values based on f2 = D2 × R2 / 60.

  When the vibration condition calculation unit 191 sets the vibration frequency f2 set on the back main shaft 210 to 50 (Hz) in order to suppress the vibration of the entire bed 11, the vibration frequency f2 = 50 (Hz) can be used as described above. This 50 (Hz) is set as the target vibration frequency because it matches a limited value. The parameter calculation unit 192 obtains the main shaft rotation speed R2 of the back main shaft 210 and the number of vibrations D2 of the cutting tool 230 so that the vibration frequency f2 = 50 (Hz) obtained by the vibration condition calculation unit 191 can be executed. When the vibration frequency f2 is set to 50 (Hz), the main shaft rotation speed R2 is set to, for example, 2400 (r / min). In this case, the number of vibrations D2 can be set to, for example, 1.25 (times / r).

  The processing execution unit 193 rotates the work W2 at a spindle rotation speed R2 of 2400 (r / min) and vibrates the vibration frequency D2 at 1.25 in order to vibrate the back spindle 210 at, for example, an opposite phase of 50 (Hz). The workpiece W2 can be subjected to vibration cutting while reciprocating the cutting tool 230 at (times / r).

Alternatively, the vibration frequency f1 of the front main shaft 110 is set to, for example, 50 (Hz), and the entire bed 11 is vibrated. When the rear main shaft 210 is vibrated at, for example, 65 (Hz), the vibration of the entire bed 11 is suppressed. In this case, the vibration frequency f2 is set to 65 (Hz).
However, since the vibration frequency f2 = 65 (Hz) does not match the limited value that can be used, 62.5 (Hz) is set as the target vibration frequency from the limited value that can be used. .

  The main shaft rotation speed R2 of the rear main shaft 210 is set to, for example, 3000 (r / min) so that the vibration frequency f2 = 62.5 (Hz) can be executed. In this case, the number of vibrations D2 can be set to, for example, 1.25 (times / r). Accordingly, the work W2 rotates at the spindle rotation speed R2 = 3000 (r / min), and the cutting tool 230 reciprocates at the vibration frequency D2 = 1.25 (times / r) to vibrate the work W2. I do.

  In the above embodiment, the spindle motor corresponds to the rotating means of the present invention, and each of the feed mechanisms 160 and 260 corresponds to the feeding means of the present invention for feeding the cutting tool in a predetermined machining feed direction. Also serves as vibration means. However, the present invention is not limited to this example. For example, the vibration means may be provided separately from the Z-axis direction feed mechanisms 160 and 260. Further, for example, the cutting tools 130 and 230 can be fed in the Z-axis direction, or the cutting tools 130 and 230 can be rotated and the main shafts 110 and 210 can be stopped.

10 machine tool 11 bed 110 front spindle 110A front headstock 120 chuck 130 cutting tool 130A front tool stand 150 X-axis feed Mechanism 151 Base 152 X-axis guide rail 153 X-axis feed table 155 Linear servo motor 155a Mover 155b Stator 160 Z-axis direction Feed mechanism 161 Base 162 Z-axis guide rail 163 Z-axis feed table 165 Linear servo motor 165a Mover 165b Stator 180 Controller 181 ··· control unit 182 ··· numerical value setting unit 183 ··· storage unit 190 ··· motor control unit 191 ··· vibration condition calculation unit 19・ ・ ・ Parameter calculation unit 193 ・ ・ ・ Machining execution unit 210 ・ ・ ・ Rear spindle 210A ・ ・ ・ Rear spindle head 220 ・ ・ ・ Chuck 230 ・ ・ ・ Cutting tool 230A ・ ・ ・ Rear tool table 250 ・ ・ ・ X-axis Directional feed mechanism 251 Base 252 X-axis guide rail 253 X-axis feed table 255 Linear servo motor 255a Mover 255b Stator 260 Z Axial feed mechanism 261 Base 262 Z-axis guide rail 263 Z-axis feed table 265 Linear servo motor 265a Mover 265b Stator

Claims (2)

One rotating means for relatively rotating one work and one cutting tool, one vibrating means for relatively vibrating the one work and the one cutting tool, and the one rotating means; Are separately configured, the other rotating means for relatively rotating the other work and the other cutting tool, and the one vibrating means are separately configured, the other work and the other cutting tool, And the other vibration means for relatively vibrating, the control device of the machine tool installed on the same bed,
When cutting the one workpiece by the one cutting tool, relative feeding of the one cutting tool in a predetermined machining feed direction accompanied by vibration by the one vibrating means and the one rotating means By controlling the relative rotation by, the cutting of the one workpiece is performed so that an overlap of the cutting edge path of the one cutting tool occurs,
The operation of the other vibrating means is controlled so as to generate vibration that suppresses the vibration of the entire bed caused by the cutting of the one work, and the other work and the other cutting tool are moved by the other vibration. The relative rotation in the predetermined machining feed direction with the vibration of the means, the number of revolutions by the other rotating means is set so that the overlap of the cutting edge paths of the other cutting tool occurs, and the other workpiece is set. Machine tool control device that performs cutting work.   A machine tool comprising the machine tool control device according to claim 1.

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