JP6875810B2 - Machine tools and their control devices - Google Patents

Description

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

Conventionally, a cutting tool for cutting a work, a rotating means for relatively rotating the cutting tool and the work, a vibrating means for relatively reciprocating the cutting tool and the work, and a cutting tool for cutting the work. Peripheral rotation per rotation according to the vibration frequency of the relative reciprocating vibration between the cutting tool and the work by the vibrating means is provided with the peripheral speed maintaining means for setting the rotation speed of the rotating means so that the peripheral speed is maintained. A machine tool that performs vibration cutting of a workpiece with vibration of the frequency of is known (see, for example, Patent Document 1).
Further, it is known that when a command can be given to the vibrating means only at a predetermined cycle, the vibration frequency as described above becomes a discontinuous value based on the cycle that can be commanded to the vibrating means. (See, for example, Patent Document 2.).

JP 2001-150201 (in particular, see claim 1 and FIG. 1) International Publication No. 2015/146946 (see in particular, claim 1 and FIG. 6).

A machine tool control device capable of maintaining a peripheral speed within a predetermined range when the vibration frequency takes a discontinuous value based on a period commandable to the vibration means is desired. The present invention solves the above-mentioned problems of the prior art, and provides a machine tool and its control device capable of achieving both a desired frequency and a desired peripheral speed.

The control device of the machine tool of the present invention for solving the above problems includes a cutting tool for cutting a work, a rotating means for relatively rotating the cutting tool and the work, and the cutting tool and the work. Vibration means for relatively reciprocating vibration, peripheral speed maintaining means for setting the rotation speed of the rotating means so that the peripheral speed at the time of cutting the work by the cutting tool is maintained, and vibration of the reciprocating vibration. It is a control device for a machine tool that is provided with a vibration frequency setting means for setting a frequency and that vibrates and cuts the workpiece with vibration of the frequency per one relative rotation according to the vibration frequency. The peripheral speed maintaining means sets the rotation speed based on the work diameter and the peripheral speed of the work, or based on the vibration frequency and the frequency, and the vibration frequency setting means sets the peripheral speed. A temporary vibration frequency is calculated based on the set rotation frequency and a predetermined frequency of the maintenance means, and an actual vibration frequency based on a commandable cycle is set based on the temporary vibration frequency. The frequency setting means cooperate with each other to set the peripheral speed to the actual frequency while keeping the peripheral speed constant regardless of the work diameter, and the actual frequency is the predetermined frequency and the allowable range. The first feature is to set the number of rotations within the predetermined range determined from.

Secondly, in the peripheral speed maintaining means, the peripheral speed maintaining means and the frequency setting means cooperate with each other to keep the actual vibration frequency and the actual frequency within the predetermined range. When setting and, the peripheral speed maintaining means is characterized in that the actual rotation speed is set so as to keep the actual frequency within the predetermined range without exceeding a predetermined maximum rotation speed. And.

Thirdly, when the peripheral speed maintaining means and the frequency setting means cooperate with each other to set the actual vibration frequency and the rotation speed that keeps the actual frequency within the predetermined range. The peripheral speed maintaining means and the vibration frequency setting means set the actual vibration frequency and set a predetermined range of the actual frequency from any one of a plurality of predetermined frequency values and the allowable range. It is characterized in that the actual rotation speed is set so that the actual frequency falls within the predetermined range of any of the plurality of predetermined ranges.

Fourth, a cutting tool for cutting a work, a rotating means for relatively rotating the cutting tool and the work, a vibrating means for relatively reciprocating the cutting tool and the work, and the cutting. The peripheral speed maintaining means for setting the rotation speed of the rotating means and the vibration frequency setting means for setting the vibration frequency of the reciprocating vibration are provided so that the peripheral speed at the time of cutting the work by the tool is maintained. A control device for a machine tool that performs vibration cutting of the work with vibration of the frequency per one relative rotation according to the vibration frequency, and the peripheral speed maintaining means is the work of the work. The rotation frequency is set based on the diameter and the predetermined peripheral speed, or based on the vibration frequency and the frequency, and the vibration frequency setting means sets the rotation speed and the predetermined frequency of the peripheral speed maintaining means. A temporary vibration frequency is calculated based on the above, and an actual vibration frequency based on a commandable cycle is set based on the temporary vibration frequency. The feature is that the actual frequency is set to the actual vibration frequency and the actual peripheral speed is set within the predetermined speed range while keeping the frequency constant regardless of the work diameter. And.

Fifth, when the peripheral speed maintaining means and the frequency setting means cooperate with each other to set the actual vibration frequency and the actual rotation speed that keeps the actual peripheral speed within the predetermined range. In addition, the frequency is characterized in that the rotation speed is set so that the peripheral speed is maintained with a predetermined value as an upper limit or a lower limit.

Sixth, when the peripheral speed maintaining means and the frequency setting means cooperate with each other to set the actual vibration frequency and the actual rotation speed that keeps the actual peripheral speed within the predetermined range. In addition, the peripheral speed maintaining means is characterized in that the actual rotation speed is set so as to keep the actual frequency within the predetermined range without exceeding a predetermined maximum rotation speed.

Seventh, the peripheral speed maintaining means maintains the frequency within a range in which the cut portion at the time of reciprocating vibration and the cut portion at the time of return of the reciprocating vibration in the vibration cutting process overlap. , The above-mentioned rotation speed is set .

Eighth, it is a machine tool provided with the above-mentioned control device.

According to the structure of the machine tool of the present invention configured as described above, the vibration frequency at which the rotation speed is set so as to maintain the frequency and the peripheral speed within a predetermined range is set. It is possible to perform cutting that achieves both peripheral speed conditions.

By setting the frequency range at which the cutting parts during the forward movement and the reverse movement can overlap, it is possible to divide the chips in the vibration cutting work.

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 nth rotation, the n + 1th rotation, and the n + 2nd rotation of a spindle. It is a flowchart of peripheral speed setting of Example 1 of this invention. This is an example of the outer shape of a workpiece finished by vibration cutting. It is a table of cutting conditions corresponding to the work diameter in Example 1 of the present invention. It is a flowchart of peripheral speed setting of Example 2 of this invention. It is a flowchart of peripheral speed setting of Example 2 of this invention. It is a table of cutting conditions corresponding to the work diameter in Example 2 of the present invention. It is a flowchart of peripheral speed setting of Example 3 of this invention. It is a table of cutting conditions corresponding to the work diameter in Example 3 of the present invention. It is a flowchart of peripheral speed setting of Example 4 of this invention. It is a table of cutting conditions corresponding to the work diameter in Example 4 of the present invention.

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

A Z-axis direction feed mechanism 160 is provided on the bed side 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 headstock 110A is movably provided in the axial direction of the spindle 110 (Z-axis direction in the drawing) by the Z-axis direction feed mechanism 160, and the spindle 110 can move along the Z-axis direction via the headstock 110A.

A mover 165a of the linear servomotor 165 is provided on the Z-axis direction feed table 163.
A stator 165b of the linear servomotor 165 is provided on the base 161.
When the Z-axis direction feed table 163 moves in the Z-axis direction by driving the linear servomotor 165, the headstock 110A moves in the Z-axis direction, and the spindle 110 moves along the Z-axis direction.

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 integrated with the bed 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 cutting tool base 130A is provided so as to be movable in the X-axis direction by the X-axis direction feed mechanism 150.
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 130.

A mover 155a of the linear servomotor 155 is provided on the X-axis direction feed table 153.
A stator 155b of the linear servomotor 155 is provided on the base 151.
When the X-axis direction feed table 153 moves in the X-axis direction by driving the linear servomotor 155, the cutting tool base 130A moves in the X-axis direction, and the cutting tool 130 moves along the X-axis direction.

Although not shown, a Y-axis direction feed mechanism may be provided with respect to the Y-axis direction orthogonal to the Z-axis direction and the X-axis direction shown.
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 Y-axis direction. The cutting tool 130 can be moved in the X-axis direction and the Y-axis direction.
The Y-axis direction feed mechanism may be provided on the bed side 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 unit 181 included in 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 are configured. As shown in FIG. 2, the headstock 110A and the cutting tool base 130A can be moved to a predetermined position in cooperation with the headstock 110A.
By moving the spindle 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 relatively moved between the work W and the cutting tool 130. The work W can be machined into a desired shape by driving the work W as a rotating means to rotate and rotating the work W with respect to the cutting tool 130.

In the present embodiment, the structure in which both the headstock 110A and the cutting tool base 130A can be moved has been described, but the headstock 110A is fixed to the bed and the cutting tool base 130A is set in the X-axis direction and the Y-axis direction. The structure may be movable in the Z-axis direction.
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 to the bed, and the headstock 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 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 this embodiment, an example in which the work W is rotated with respect to the cutting tool 130 will be described, but a rotating tool such as a drill may be used for the cutting tool 130, and the cutting tool 130 may be rotated 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.

As shown in FIG. 3, the control unit 181 of the control device 180 moves the spindle 110A forward by a predetermined forward amount (forward movement) and then moves backward by a predetermined backward amount (return). The cutting tool 130 can be fed to the work W in the feed direction by the difference (advance amount) between the forward amount and the backward amount with vibration along the feed direction.
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 spindle 110A and the cutting tool base 130A forward and backward. As a result, the cutting tool 130 can be vibrated with respect to the work W.
The cutting tool 130 is fed to the work W with vibration along the feeding direction by a feeding means that also serves as a vibrating means, and processes the work W.

When the work W is externally cut into a predetermined shape by the cutting tool 130, the outer peripheral surface of the work is machined in a sinusoidal shape by the cutting tool 130 as shown in FIG.
This is the amount of change in the position of the cutting tool 130 when the spindle phase changes from 0 ° to 360 ° for one rotation of the spindle 110 in a virtual line (one-point chain line) passing through a valley of a sinusoidal waveform. The total amount of progress is the feed amount of the cutting tool 130.
FIG. 4 shows an example in which the frequency N of the cutting tool base 130A per rotation of the spindle 110 is 3.5 times (frequency N = 3.5).
Further, in FIG. 4, in order to explain the state of the outer peripheral surface of the work in an easy-to-understand manner, the vertical axis of the graph is the position of the cutting tool 130 with respect to the work W in the machining feed direction, and the horizontal axis of the graph is one rotation of the work W, that is, the main axis. The phase is set from 0 ° to 360 °, and the cutting locus of the vibration cutting process by the cutting tool 130 on the outer peripheral surface of the work developed along the circumferential direction is shown.

Cutting locus of the outer peripheral surface of the work at the n (n is an integer of 1 or more) rotation of the spindle 110 machined by the cutting tool 130 (shown by a solid line in FIG. 4) and cutting of the outer peripheral surface of the work at the n + 1th rotation of the spindle 110. The locus (shown by a broken line in FIG. 4) is deviated from the main axis phase direction (horizontal axis direction in the graph of FIG. 4).
Specifically, the position of the shallowest point of the phase valley of the shape of the outer peripheral surface of the work shown by the broken line in FIG. 4 (in other words, the apex of the mountain seen from the cutting tool 130) is shown by the solid line in FIG. The position of the shallowest point of the phase valley of the outer peripheral surface shape (in other words, the apex of the mountain seen from the cutting tool 130) is deviated from the position in the main axis phase direction (horizontal axis direction of the graph).

Since the vibration cutting process has a phase and amplitude at which the cutting locus during the reciprocating vibration and the cutting locus during the reciprocation intersect, the cutting part during the reciprocating movement by the cutting tool 130 and the cutting locus during the rewinding A part of the cut part overlaps, and the cut part at the n + 1th rotation on the outer peripheral surface of the work includes the cut part at the nth rotation, and when passing through this cut cutting locus, vibration cutting is performed. During the machining feed direction, the cutting tool 130 does not cut the work W, resulting in an idle swing operation.
The cutting chips generated from the work W during the vibration cutting process are sequentially divided by this air swing operation.
As a result, the machine tool 100 can smoothly perform the vibration cutting process of the work W while dividing the cutting chips by the reciprocating vibration along the machining feed direction of the cutting tool 130.

FIG. 4 shows an example in which the cut portion at the time of the current movement and the cut portion at the time of the next return partially overlap the shallowest point of the phase valley.
However, the idling operation of the cutting tool 130 occurs, for example, if the cutting portion of the work outer peripheral surface at the n + 1th rotation of the spindle 110 includes the cut portion of the work outer peripheral surface at the nth rotation of the spindle 110.
In other words, the cutting locus of the cutting tool 130 at the time of recovery at the n + 1th rotation (n is an integer of 1 or more) on the outer peripheral surface of the work may reach the cutting locus of the cutting tool 130 at the nth rotation of the outer peripheral surface of the work. ..
The cut portion of the outer peripheral surface of the work at the n + 1th rotation of the spindle 110 and the cut portion of the outer peripheral surface of the work at the nth rotation of the spindle 110 are brought close to each other, and the cutting chips are divided so as to break at the close portion. May be good.

As shown in FIG. 4, the phases of the shapes cut by the cutting tool 130 in the work W at the n + 1th rotation and the nth rotation need not be the same (in-phase), and it is not always necessary to invert 180 °.
For example, the frequency N, which is the number of times the work W and the cutting tool 130 are reciprocally vibrated while rotating the spindle 110 once, is, for example, 1.1, 1.25, 2.6, 3.75 (times / r). ) Etc.
Further, the frequency N can be set to a value smaller than 1 (times / r) (0 <frequency N <1.0).
When the frequency N is set to a value smaller than 1 (times / r), the spindle 110 rotates more than one rotation by the time the cutting tool base 130A makes one reciprocation.

In the machine tool 100, the control unit 181 of the control device 180 issues an operation command at a predetermined command cycle.
By this operation command, the reciprocating vibration of the spindle 110A (spindle 110) or the cutting tool base 130A (cutting tool 130) can be operated at a predetermined vibration frequency f based on the command cycle of the control unit 181.
For example, in the case of a machine tool 100 capable of sending an operation command 500 times per second by the control unit 181, the command cycle of the control unit 181 is 1 (second) ÷ 500 (times) = 2 (ms / time). Is the reference cycle.

The command cycle is determined based on the reference cycle, and is generally an integral multiple of the reference cycle.
For example, if 10 (ms), which is 5 times the reference cycle (2 (ms)), is set as the command cycle, forward and backward movements can be executed every 10 (ms), and 1 ÷ (0.002 × 5). ) = 100.0 (Hz), the headstock 110A (spindle 110) or the cutting tool base 130A (cutting tool 130) can be reciprocally vibrated.

In addition, the headstock 110A (spindle 110) or the cutting tool base 130A (cutting tool 130) can be reciprocally vibrated only at a plurality of predetermined limited frequencies that are the reciprocals of a value that is an integral multiple of the reference period.
When the collection of vibration frequency f corresponding to the command cycle and oscillating frequency group, the vibration frequency of the spindle slide 110A or cutting tool post 130A is determined to a value selected from the vibration frequency group.
Depending on the control device 180 (control unit 181), the command cycle may be set in a multiple other than an integral multiple of the reference cycle (2 (ms)).

When the spindle 110A (spindle 110) or the cutting tool base 130A (cutting tool 130) is reciprocally vibrated, the frequency N is determined by the following equation, where S is the rotation speed of the spindle 110.
N = f × 60 / S
The frequency N is proportional to the vibration frequency f and inversely proportional to the rotation speed S.
The higher the vibration frequency f and the lower the frequency N, the higher the speed of the spindle 110.

In the machine tool 100 of the present embodiment, the rotation speed S, the frequency N, and the vibration frequency f are used as parameters, and the user sets the value of a predetermined parameter in the control unit 181 via the numerical value setting unit 182 or the like. Is configured to allow
The parameters can be set in the control unit 181 as parameter values, for example, the values of the rotation speed S and the frequency N can be described in the machining program and set, or a predetermined program block. The frequency N can be set as an argument in (one line of the program).

In particular, if the frequency N is configured to be set as an argument in the program block of the machining program, the rotation speed S of the spindle 110 generally described on the machining program and the argument in the program block are described. With the frequency N, the user can easily set the rotation speed S and the frequency N in the control unit 181 from the machining program.

The control unit 181 rotates the spindle 110 at a rotation speed based on the set rotation speed S, and reciprocates the cutting tool 130 along the machining feed direction at a frequency based on the set frequency N for machining. The movement of the headstock 110A or the cutting tool base 130A is controlled so that the headstock is fed in the feed direction.

The peripheral speed maintaining portion 183 of the peripheral speed maintaining means to the control unit 180 and the vibration frequency setting unit 184 as the oscillation frequency setting means.
The peripheral speed maintaining unit 183 is configured to automatically set the rotation speed S based on the work diameter and the peripheral speed so that the peripheral speed at the time of cutting the work W by the cutting tool 130 is maintained. ing.
Assuming that the peripheral speed to be maintained is V and the work diameter is Wd, the rotation speed S is determined by the following equation.
S = V ÷ (π × Wd)
However, since the rotation speed S is determined based on the frequency N and the vibration frequency f as described above, the frequency N is maintained within a predetermined range and the peripheral speed V is maintained with an error in the predetermined range allowed. The peripheral speed maintenance unit 183 and the vibration frequency setting unit 184 are linked so that the vibration frequency setting unit 184 sets the vibration frequency f at which the peripheral speed maintenance unit 183 can set the rotation speed S. ..

For the predetermined range in which the frequency N is maintained, for example, the permissible range B can be set in advance and the frequency N ± the permissible range B can be set.
The peripheral speed maintenance unit 183 of the present embodiment is configured so as not to allow rotation exceeding a predetermined maximum rotation speed Smax.
The peripheral speed V, the maximum rotation speed Smax, the allowable range B, the work diameter Wd, etc. maintained by the peripheral speed maintaining unit 183 can be set in the control unit 181 via the numerical value setting unit 182 or the like.

Settings for the control unit 181 such as peripheral speed V, maximum rotation speed Smax, allowable range B, and work diameter Wd can be input to the control unit 181 as parameter values. For example, each value is described in the machining program. It can be set as an argument in a predetermined program block (one line of the program).
When the peripheral speed maintenance unit 183 is operated, the control unit 181 has a spindle according to the vibration frequency f set by the vibration frequency setting unit 184 and the rotation speed S and the frequency N set by the peripheral speed maintenance unit 183. The 110 is rotated and the movement of the spindle 110A or the cutting tool base 130A is controlled.

<Example 1>
The work diameter Wd of the work W to be machined, the peripheral speed V maintained by the peripheral speed maintenance unit 183, the maximum rotation speed Smax, the frequency N, the allowable range B, etc. are set, and the work is in the operating state of the peripheral speed maintenance unit 183. When the machining of W is started, as shown in FIG. 5, the peripheral speed maintaining portion 183 becomes the peripheral speed V based on the work diameter Wd according to the movement of the cutting tool 130 in the radial direction of the work W. calculates the rotational speed S t provisional (STEP 103).

Vibration frequency setting unit 184, and a rotational speed S t of the calculated provisionally with frequency N, and calculates the vibration frequency f t of the temporary (STEP 104).
Vibration frequency setting unit 184, the value closest to the vibration frequency f t of the temporary calculated from the vibration frequency group select (recently Nitinol), to the control unit 181 the value as an actual vibration frequency f And set (STEP105).

Next, the peripheral speed maintaining unit 183 determines the rotational speed S t of the calculated provisional, to or smaller than a maximum speed Smax, which is set as a command value (STEP 106).
When the rotational speed S t of the calculated provisional or less maximum speed Smax (determination YES), the peripheral speed maintaining unit 183, and a real oscillation frequency f and the temporary speed S t, the frequency of temporary N Calculate t (STEP107).
Next, the peripheral speed maintenance unit 183 determines whether or not the calculated temporary frequency N t is within the range of the frequency N ± allowable range B set as the command value (STEP 108).
When the calculated temporary frequency N t is within the range of the frequency N ± the allowable range B (determination YES), the peripheral speed maintenance unit 183 uses the calculated temporary rotation speed St as the actual rotation speed. It is set as S in the control unit 181 (STEP109).
The control unit 181 operates the spindle 110 and the cutting tool 130 with the set actual vibration frequency f and the actual rotation speed S, and has an actual frequency Nr (provisional frequency Nt) . Perform machining by vibration.

In STEP106, when the rotational speed S t of the calculated provisional exceeds the maximum speed Smax (determination NO), the peripheral speed maintaining unit 183, the actual rotation speed S and the maximum speed Smax (STEP 110), STEP 109 And set to the control unit 181.

In STEP108, when the frequency N t of the calculated provisional is not within the range of frequencies N ± tolerance B (determination NO), the actual frequency Nr is when exceeds the upper limit of the range of the command value The actual rotation speed S is calculated so that the upper limit value is the frequency N + the allowable range B, and when the actual frequency Nr is less than the lower limit value, the actual frequency Nr is the lower limit value of the command value range N-the allowable range B. (STEP111), the process proceeds to STEP109, and the control unit 181 is set.

For example, the vibration frequency group, 31.3,33.3,35.7,38.5,41.7,45.5,50.0,55.6,62.5,71.4,83. 3, For a machine tool of 100.0 (Hz), a work W having a work diameter Wd = 10.0 (mm) has a work diameter Wd = 3.0 (mm) at the tip, as shown in FIG. When processing into a shape having multiple stages, peripheral speed V = 50 (m / min), maximum rotation speed Smax = 7000 (r / min), frequency N = 1.5 (times / r), vibration The permissible range B of the number N is set to ± 0.1 (times / r).

For a predetermined work diameter Wd, the actual rotation speed S determined based on the set peripheral speed V, the actual vibration frequency f, the set actual rotation speed S and the actual frequency at the actual vibration frequency f. Nr, the actual peripheral speed (actual peripheral speed Vr) is shown in FIG. 7, the work diameter Wd = 9.0 (mm), the temporary rotation speed St = 1769 (r / min), and the temporary vibration frequency f. because it is calculated as t = 44.2 (Hz), the actual oscillation frequency f is set to 45.5 closest to the vibration frequency f t of the calculated provisional (Hz).

Since the provisional rotation speed St = 1769 (r / min) is equal to or less than the maximum rotation speed Smax = 7000 (r / min), the actual frequency Nr = 1.54 (times / r) is calculated and the actual vibration. The number Nr = 1.54 (times / r) is within the permissible range (1.4 to 1.6).
When the work diameter Wd = 9.0 (mm), the actual rotation speed S = 1769 (r / min), the actual vibration frequency f = 45.5 (Hz) are set, and the actual peripheral speed Vr = 50. Processing is performed with (m / min) and an actual frequency Nr = 1.54 (times / r). The peripheral speed V is maintained at 50 (m / min).

In the work diameter Wd = 3.7 (mm), the rotational speed S t = 4302 (r / min ) of the provisional vibration frequency of the provisional t f = 107.6 and (Hz) is calculated, the actual vibration frequency f 100 It is set to 0.0 (Hz).

Temporary speed S t = 4302 (r / min ) , because it is below the maximum rotational speed Smax = 7000 (r / min) , the frequency N t = 1.39 tentative (times / r) is calculated However, since the provisional frequency N t = 1.39 (times / r) is less than the lower limit of the permissible range (1.4 to 1.6), the actual frequency Nr is the lower limit of the permissible range 1.4. The rotation speed S = 4286 (r / min) is set so as to be.
Therefore, when the work diameter Wd = 3.7 (mm), the actual rotation speed S = 4286 (r / min) and the actual vibration frequency f = 100.0 (Hz) are set, and the actual peripheral speed V≈ Processing is performed at 50 (m / min) and the actual frequency Nr = 1.4 (times / r), and the peripheral speed V is almost maintained at 50 (m / min).
After that, the same process is performed up to the work diameter Wd = 3.0 (mm).

Thus, to maintain the peripheral speed V constant, the actual rotational speed S to maintain the actual frequency N r within a predetermined range so that you can set peripheral speed maintaining means, from the vibration frequency group A vibration frequency setting means for setting an actual vibration frequency f and setting it as a peripheral speed maintaining means is provided.
Since the peripheral speed V is maintained constant according to the work diameter Wd, it is possible to perform machining accompanied by vibration with stable machining accuracy and grain.

However, when the workpiece diameter Wd is less than 3.7 (mm) is set to the actual maximum value of the vibration frequency f of vibration frequency group 100 (Hz), the actual frequency Nr is allowable range lower limit Since the actual rotation speed S is set to be 1.4, the peripheral speed V is lower than 50 (m / min).
As the control of the first embodiment, can be set to the actual speed S and the actual vibration frequency f value, because it is limited by the maximum speed Smax and vibration frequency group, the actual frequency of N r is the acceptable range If it deviates from B, it may be difficult to maintain the peripheral speed V.
In the first embodiment has been described with reference to frequency N = 1.5 (times / r), the maximum rotational speed of the actual rotational speed S when the rotational speed S t tentative exceeds the upper Smax the actual frequency of N r can be controlled so as to maintain a predetermined range as.

<Example 2>
And to the control unit 181 sets the two frequency N, the oscillation frequency setting unit 184, the frequency N t tentative calculated is maintained in a predetermined range in one of the set the frequency N It is also possible to set the actual vibration frequency f as described above.

The work diameter Wd of the work W to be machined, the peripheral speed V maintained by the peripheral speed maintenance unit 183, the maximum rotation speed Smax, the two frequencies N, the permissible range B, etc. are set, and the machining of the work W is started. As shown in FIG. 8, the larger value of the two frequency N is set to the first value N1 , the smaller value is set to the second value N2, and the first value N1 is set in the control unit 181 (STEP201). ..
The second value N2 can be stored, for example, by providing a memory in the numerical value setting unit 182.
Since STEP 203 to 208 and STEP 209, 210 shown in FIG. 8 are the same as the processing of the reference numerals having the same last two digits of STEP 103 to 108 or STEP 109 to 110, the description thereof will be omitted.

If the temporary frequency N t calculated in STEP 208 is not within the set frequency N 1 ± allowable range B, as shown in FIG. 9, the peripheral speed maintenance unit 183 has a temporary frequency N t. It is determined whether or not the upper limit value (N1 + B) is exceeded (STEP211).
If the determination is YES in STEP 211, the actual rotation speed S is calculated (STEP 212) so that the actual frequency Nr becomes the upper limit (N1 + B) of the command value range, and the process shifts to STEP 209 and is set in the control unit 181. ..

If the determination in STEP211 is NO, then that is, when the frequency N t tentative is less than the lower limit of the range of the command value (N1-B), the peripheral speed maintaining unit 183, first is set frequency N It is determined whether or not it matches the value N1 of (STEP 213).
When the frequency N is the first value N1 (determination YES), the control unit 181 calls the second value N2 from the memory of the numerical value setting unit 182, sets the frequency N (STEP214), and shifts to STEP203. ..
When the frequency N does not match the first value N1 , that is, when the frequency N is the second value N2 (determination NO), the actual frequency Nr is the lower limit of the frequency N in the command value range (N2). The actual vibration frequency f and the actual rotation speed S are calculated so as to be −B) or the upper limit (N2 + B), and the process shifts to STEP209 and is set in the control unit 181.

For example, for a machine tool having the same vibration frequency group as in Example 1, the workpiece W, when processed into a shape having a plurality of stages as shown in FIG. 6, the circumferential speed V = 50 (m / min ), Maximum rotation speed Smax = 7000 (r / min), first value of frequency N = 1.5 (times / r) and second value = 0.5 (times / r), frequency N The permissible range B = ± 0.1 (times / r) is set.

For a predetermined work diameter Wd, the actual rotation speed S, the actual vibration frequency f, the set actual rotation speed S and the actual vibration frequency f determined based on the set peripheral speed V Nr, the actual peripheral speed (actual peripheral speed Vr) is shown in FIG.
First, the control unit 181 sets the first value N1 to 1.5 (times / r), and similarly to the first embodiment, the temporary rotation speed St , the temporary vibration frequency ft , and the temporary vibration. performs a process for calculating the number N t, when the frequency N t tentative is frequency N ± tolerance B (1.4 to 1.6), as in example 1, on the basis of the peripheral speed V The actual vibration frequency f and the actual rotation speed S are set, the peripheral speed V is maintained at 50 (m / min), the actual peripheral speed Vr = 50 (m / min), and the processing is performed at a predetermined actual frequency Nr. Is done.

On the other hand, for example, when the work diameter Wd = 3.7 (mm), the temporary frequency N t = 1.39 (times / r) is calculated, and the temporary frequency N t = 1.39 is within the permissible range (1). Since it is less than the lower limit of .4 to 1.6), the frequency N is set to the second value N2 (0.5).
For frequency N = 0.5 (times / r), the tentative vibration frequency f t = 35.9 (Hz) is calculated and set to the actual vibration frequency f = 35.7 (Hz).
Since tentative rotational speed S t = 4302 and (r / min) and the actual vibration frequency f = 35.7 (Hz), the frequency N t = 0.50 tentative is calculated tentative frequency N t = 0.50 (times / r) is within the permissible range (0.4 to 0.6).

Therefore, in the state of the work diameter Wd = 3.7 (mm), the actual rotation speed S = 4302 (r / min) and the actual vibration frequency so that the peripheral speed V = 50 (m / min) is maintained. The processing is performed with f = 35.7 (Hz) set, the actual peripheral speed Vr = 50 (m / min), and the actual frequency Nr = 0.50 (times / r).
After that, the same process is performed up to the work diameter Wd = 3.0 (mm) with the frequency N as the second value N2.
Compared with Example 1 in which the frequency N = 1.5 (times / r) is set, the frequency N is set to the first value N1 (1.5) and the second value N2 (0.5). By setting, the peripheral speed V = 50 (m / min) is maintained even when the work diameter is smaller than Wd = 3.7 (mm).

In this way, in order to maintain the peripheral speed V constant, it is set to be maintained within a predetermined range at any of a plurality of predetermined frequencies N, and the value of the set frequency N is predetermined. A peripheral speed maintaining means for calling and setting a small value frequency N when the range is exceeded is provided.

As a result, the range of machining dimensions in which the peripheral speed V is maintained constant can be expanded according to the work diameter Wd, and machining with vibration can be performed with more stable machining accuracy and grain.

The explanation was given to set a large value of the frequency N as the first value N1 , but when setting the rotation speed, each parameter was obtained using the first value N1 and the second value N2, and the actual peripheral speed Vr and The control may be such that the value on which the difference between the actual frequency Nr and the peripheral speed V set as the command value and the frequency N becomes smaller is selected as the frequency N.
The number of frequencies N set as the command value may be three or more.
The permissible range B may be set to a different value for each of a plurality of command values of the frequency N.

<Example 3>
The frequency N by a constant value, the actual vibration speed Nr can be configured to set the actual vibration frequency f of the actual rotational speed S such that frequency N.
As shown in FIG. 11, STEP 303 to 305 and STEP 310 are the same as the processing of the code in which the last two digits of STEP 103 to 105 or STEP 110 are common, and thus the description thereof will be omitted.

After setting the actual vibration frequency f in STEP 305, the peripheral speed maintaining unit 183 calculates the rotational speed S t tentative from the actual vibration frequency f and the actual frequency N (STEP305-2).
Rotational speed S t tentative peripheral speed maintaining unit 183 is calculated to determine whether it is below the maximum rotational speed Smax (STEP 306), if the determination is YES, the process proceeds to STEP 309, the rotation speed St provisional set in the control unit 181 as a rotational speed S.
If the determination is NO, the process proceeds to STEP310.

For example, for a machine tool having the same vibration frequency group as in Example 1, the workpiece W, when processed into a shape having a plurality of stages as shown in FIG. 6, the circumferential speed V = 50 (m / min ), The maximum rotation speed Smax = 7000 (r / min), and the frequency N = 1.5 (times / r).

For a predetermined work diameter Wd, the temporary vibration frequency ft and the temporary rotation speed St determined based on the set peripheral speed V are the work diameter Wd = 9.0 (mm) and the temporary rotation speed. S t = 1769 (r / min ), since the provisional vibration frequency f t = 44.2 and (Hz) is calculated, the actual vibration frequency f closest to the vibration frequency f t of the calculated provisional 45.5 Set to (Hz).

As shown in FIG. 12, a temporary rotation speed St = 1820 (r / min) at which the frequency N = 1.5 (times / r) at the actual vibration frequency f = 45.5 (Hz) is calculated. Will be done. Since the temporary rotation speed St = 1820 (r / min) is equal to or less than the maximum rotation speed Smax = 7000 (r / min), the provisional rotation speed St = 1820 (r / min) is set as the actual rotation speed S. It is set in the control unit 181 and the frequency N = 1.5 (times / r) is maintained as the actual frequency Nr , and the processing is performed at the actual peripheral speed Vr = 51.45 (m / min).
After that, the same process is performed up to the work diameter Wd = 3.0 (mm).

Thus, to maintain the peripheral speed V in a predetermined speed range, the actual vibration speed Nr as the actual rotational speed S such that frequency N can be set peripheral speed maintaining means, in the vibration frequency group A vibration frequency setting means for calculating the actual vibration frequency f from the above and setting it as the peripheral speed maintaining means is provided.
Since the peripheral speed V is maintained within a predetermined speed range according to the work diameter Wd, it is possible to perform machining with vibration with more stable machining accuracy and grain.

<Example 4>
As shown in the third embodiment, when the frequency N is set to a constant value and the actual frequency f is set to be the actual rotation speed S such that the actual frequency Nr is the frequency N, the actual peripheral speed Vr is set. may be configured to operate in the following peripheral velocity V of the set set configuration or actual peripheral speed Vr is operated in a range of more than the circumferential speed V as the lower limit of the peripheral speed V was peripheral speed V as upper limit.
The steps of STEP 403, 304 and STEP 405-2, 406, 409, 410 shown in FIG. 13 are the same as the processing of codes having the same last two digits of STEP 103, 104 or STEP 305-2, 306, 309, 310, respectively. Therefore, the description is omitted.

The peripheral speed V is determined by the following equation.
V = (f × 60 × π × Wd) ÷ N
Vibration frequency setting unit 184 selects the closest value at the vibration frequency f t or more temporary value calculated in STEP 40 4 from the vibration frequency group, the value is set to the actual vibration frequency f.
From this, the actual peripheral speed Vr becomes equal to or higher than the set peripheral speed V.
Incidentally, the oscillation frequency setting unit 184, the nearest value selected from among the oscillation frequency group at the vibration frequency f t following temporary value calculated in STEP 40 4, the value is set to the actual vibration frequency f By configuring in this way, the actual peripheral speed Vr can be set to the set peripheral speed V or less.

For example, for a machine tool having the same vibration frequency group as in Example 1, the workpiece W, when processed into a shape having a plurality of stages as shown in FIG. 6, the circumferential speed V = 50 (m / min ) Above, the maximum rotation speed Smax = 7000 (r / min) and the frequency N = 1.5 (times / r) are set.

For a given workpiece diameter Wd, "circumferential speed V ≧ 50 real peripheral speed Vr is 50 (m / min) or more and becomes the actual vibration frequency f, the real rotational speed S, and the actual peripheral speed Vr is 14 The actual vibration frequency f, the actual rotation speed S, and the actual peripheral speed Vr at which the actual peripheral speed is 50 (m / min) or less are shown in the “peripheral speed V ≦ 50” column of FIG. Is done.
In this case, the work diameter Wd = 9.0 (mm), the rotational speed S = 1 768 (r / min ), is calculated and the vibration of the temporary frequency f t = 44.2 (Hz), the actual oscillation frequency f It is set to the vibration of the calculated provisional frequency f t = 44.2 45.5 nearest (Hz) or higher (Hz).

At the actual vibration frequency f = 45.5 (Hz), a temporary rotation speed St = 1820 (r / min) at which the frequency N = 1.5 (times / r) is calculated.
Since the temporary rotation speed St = 1820 (r / min) is equal to or less than the maximum rotation speed Smax = 7000 (r / min), the provisional rotation speed St = 1820 (r / min) is controlled as the rotation speed S. It is set in the unit 181 and the frequency N = 1.5 (times / r) is maintained, and the processing is performed at the actual peripheral speed Vr = 51.45 (m / min) equal to or higher than the set peripheral speed V.
After that, the same process is performed up to the work diameter Wd = 3.0 (mm).

When the peripheral speed condition is peripheral speed V = 50 (m / min) or less, the actual vibration frequency f = 41.7 (Hz) is set, and the temporary rotation speed St = 1668 (r / min). Is set in the control unit 181 as the rotation speed S , the frequency N = 1.5 (times / r) is maintained, and the actual peripheral speed Vr = 47.15 (m / min) equal to or less than the set peripheral speed V. Processing is done.

Even when the actual frequency Nr is set to a predetermined frequency N and the peripheral speed V is set to a condition equal to or less than a set value, the peripheral speed V can be set by setting the actual vibration frequency f by the vibration frequency setting unit 184. It is possible to set the actual rotation speed S which is maintained in a predetermined range and the actual frequency Nr is maintained by allowing an error in the predetermined range.
By setting the actual peripheral speed Vr to be equal to or higher than the peripheral speed V with the peripheral speed V as the lower limit, the machining time of the work W can be shortened.
Further, by setting the actual peripheral speed Vr to the peripheral speed V or less with the peripheral speed V as the upper limit, it may be possible to suppress the wear of the cutting tool 130.

In the case the control of the third and fourth embodiments, the possible values for the vibration frequency f, because it is limited by the vibration frequency group, oscillation frequency f is set to the maximum value of the vibration frequency group, As the work diameter Wd becomes smaller, the peripheral speed V decreases, and it may be difficult to maintain the peripheral speed V.

100 ・ ・ ・ Machine tool 110 ・ ・ ・ Spindle (rotation means)
110A ・ ・ ・ Spindle 120 ・ ・ ・ Chuck (work holding means)
130 ・ ・ ・ Cutting tool 130A ・ ・ ・ Cutting tool base 150 ・ ・ ・ X-axis direction feed mechanism (feed means, vibration means)
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 ・ ・ ・ Stator 160 ・ ・ ・ Z-axis direction feed mechanism (feed means, vibration means)
161 ・ ・ ・ Base 162 ・ ・ ・ Z-axis direction guide rail 163 ・ ・ ・ Z-axis direction feed table 164 ・ ・ ・ Z-axis direction guide 165 ・ ・ ・ Linear servomotor 165a ・ ・ ・ Movable element 165b ・ ・ ・ Stator 180 ・ ・ ・ Control device 181 ・ ・ ・ Control unit (cutting control means)
182 ・ ・ ・ Numerical value setting unit (resetting means)
183 ・ ・ ・ Peripheral speed maintenance unit (peripheral speed maintenance means)
184 ・ ・ ・ Vibration frequency setting unit (vibration frequency setting means)
f ・ ・ ・Actual vibration frequency N ・ ・ ・ Frequency Nr ・ ・ ・ Actual frequency (actual frequency)
S ・ ・ ・Actual rotation speed W ・ ・ ・ Work Wd ・ ・ ・ Work diameter

Claims (8)

A cutting tool for cutting a work, a rotating means for relatively rotating the cutting tool and the work, a vibrating means for relatively reciprocating the cutting tool and the work, and the work by the cutting tool. comprising of a peripheral speed maintaining means for setting the rotational speed of said rotating means as circumferential speed during cutting is maintained, and a vibration frequency setting means for setting the vibration frequency of the reciprocating vibration, the vibration frequency It is a control device of a machine tool that performs vibration cutting of the work with vibration of the frequency per one rotation of the relative rotation corresponding to the relative rotation.
The peripheral speed maintaining means sets the rotation speed based on the work diameter and the peripheral speed of the work, or based on the vibration frequency and the frequency.
The vibration frequency setting means calculates a temporary vibration frequency based on the rotation speed set by the peripheral speed maintaining means and a predetermined frequency, and the actual vibration frequency based on a period that can be commanded based on the temporary vibration frequency. Set and
The peripheral speed maintaining means and the frequency setting means cooperate with each other to set the peripheral speed to the actual vibration frequency and set the actual frequency to the predetermined value while keeping the peripheral speed constant regardless of the work diameter. A machine tool control device that sets the number of revolutions within a predetermined range defined by the frequency and allowable range of the machine tool. When the peripheral speed maintaining means and the frequency setting means cooperate with each other to set the actual vibration frequency and the rotation speed that keeps the actual frequency within the predetermined range.
The peripheral speed maintaining means sets the actual rotational speed accommodate the actual frequency prior Symbol without exceeding the maximum speed predetermined for the range of the predetermined range, the machine tool according to claim 1 Control device. When the peripheral speed maintaining means and the frequency setting means cooperate with each other to set the actual vibration frequency and the rotation speed that keeps the actual frequency within the predetermined range.
The peripheral speed maintaining means and the vibration frequency setting means set the actual vibration frequency and set a predetermined range of the actual frequency from any one of a plurality of predetermined frequency values and the allowable range. determined actual frequency said said set the actual rotational speed falls within the scope of any of the predetermined range of said plurality of predetermined ranges, machine tool control apparatus according to請Motomeko 1 or 2. A cutting tool for cutting a work, a rotating means for relatively rotating the cutting tool and the work, a vibrating means for relatively reciprocating the cutting tool and the work, and the work by the cutting tool. comprising of a peripheral speed maintaining means for setting the rotational speed of said rotating means as circumferential speed during cutting is maintained, and a vibration frequency setting means for setting the vibration frequency of the reciprocating vibration, the vibration frequency It is a control device of a machine tool that performs vibration cutting of the work with vibration of the frequency per one rotation of the relative rotation corresponding to the relative rotation.
The peripheral speed maintaining means sets the rotation speed based on the work diameter of the work and a predetermined peripheral speed, or based on the vibration frequency and the frequency.
The vibration frequency setting means calculates a temporary vibration frequency based on the rotation speed set by the peripheral speed maintaining means and a predetermined frequency, and the actual vibration frequency based on a period that can be commanded based on the temporary vibration frequency. Set and
The peripheral speed maintaining means and the frequency setting means cooperate with each other to set the actual vibration frequency and the actual peripheral speed while keeping the actual frequency constant regardless of the work diameter. A machine tool control device that sets the actual number of revolutions within a predetermined speed range. When the peripheral speed maintaining means and the frequency setting means cooperate with each other to set the actual vibration frequency and the actual rotation speed that keeps the actual peripheral speed within the predetermined range.
The frequency, the peripheral speed is set to the rotational speed so as to maintain a predetermined value as the upper limit or lower limit, the machine tool control apparatus according to claim 4. When the peripheral speed maintaining means and the frequency setting means cooperate with each other to set the actual vibration frequency and the actual rotation speed that keeps the actual peripheral speed within the predetermined range.
The peripheral speed maintaining means sets the actual rotational speed kept within the range of the predetermined range before Symbol actual frequency without exceeding the maximum speed to a predetermined, according to claim 4 or 5 Machine tool control device. The peripheral speed maintaining means has the rotation speed so that the frequency is maintained within a range in which the cutting portion at the time of reciprocating vibration and the cutting portion at the time of return in the vibration cutting process overlap. setting the machine tool control apparatus according to any one of claims 1-6. A machine tool provided with the control device according to any one of claims 1 to 7.

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