JP2023141865A - Machine tool - Google Patents

Abstract

To provide a machine tool capable of automatically setting, a frequency at which a scrape cutting effect can be acquired, in processing in which, a relative speed of a tool and a workpiece is varied periodically.SOLUTION: In a machine tool 100 for relatively moving a rotary tool T1 and a workpiece W for performing drilling, the machine tool has; a main shaft 112 for rotating the fitted rotary tool T1; a table 106 to which the workpiece W is fitted; a Z axis feeding unit 118 for relatively moving the main shaft 112 and the table 106 along a center axis direction of the main shaft 112; and a control unit 10 for, when receiving a command of oscillation hole processing for drilling the workpiece W by varying, the relative movement speed of the main shaft 112 and the table 106 at the oscillation frequency, setting an oscillation frequency different from a value which is obtained by multiplying the rotary frequency of the main shaft 112 by a blade number of the rotary tool T1, and actuating the Z axis feeding unit 118 by the oscillation frequency.SELECTED DRAWING: Figure 1

Description

The present invention relates to machine tools.

Continuous chips generated during hole machining and turning operations such as drilling and boring machining can damage the tool, damage the machined surface, and eject chips from the processing machine. Conventionally, problems such as clogging of processing equipment with chips have been a problem.

To solve this problem, during drilling, the drill is moved back axially to eject the chips from the hole being drilled, then the drill is moved forward again axially, and this process is repeated until the desired depth is reached. A step-feed processing method for drilling holes has been conventionally known. However, in this machining method, since the drill unit is moved backward, it takes time for the reciprocating operation, and as a result, the machining time becomes longer. In addition, when the drill unit moves back and forth, the tip of the drill separates from the workpiece, so when the tip of the drill comes into contact with the workpiece again in a manner that causes an impact, the cutting edge may be chipped or noise may be generated due to the contact. There is a problem. Furthermore, since the moving distance increases due to the reciprocating motion, the life of the feed shaft device is adversely affected. Therefore, Patent Document 1 discloses a hole machining method in which a rotary tool such as a drill, a boring cutter, or a counterbore cutter and a workpiece are moved relative to each other to form a hole in the workpiece, in which the feed rate in the central axis direction of the rotary tool, That is, a hole machining method is disclosed in which a hole is machined in a workpiece by changing the relative movement speed between the rotary tool and the workpiece so as to repeatedly increase and decrease the speed within a range in which the rotary tool does not retreat in the direction of its central axis.

In the method described in Patent Document 1, when machining is performed by periodically increasing and decreasing the feed rate, there is an optimal oscillation frequency that achieves the chip breaking effect, and this oscillation frequency is determined by the machining conditions. It is shown. However, in machining where the feed rate is increased or decreased by the oscillation frequency, the operator calculates and sets the oscillation frequency according to a wide variety of machining conditions based on experience, which may increase the number of man-hours. There is.

Japanese Patent Application Publication No. 2015-052927

In view of the above circumstances, the present invention provides a machine tool that can automatically set a frequency at which a chip breaking effect can be obtained when machining is performed by periodically varying the relative speed between a tool and a workpiece. The purpose is to provide.

According to one aspect of the present invention, there is provided a machine tool for drilling a hole by relatively moving a rotary tool and a workpiece, the main shaft rotating the attached rotary tool, a table to which the workpiece is attached, and the main shaft and the table. When receiving a command for oscillating hole machining, which involves machining a hole in a workpiece by varying the relative movement speed between the main axis and the table at the oscillation frequency, , a control device that sets a swing frequency different from a value obtained by multiplying the rotational frequency of the spindle and the number of teeth of the rotary tool, and operates a feed shaft section at the swing frequency. be done.

Further, according to one aspect of the present invention, there is provided a machine tool that performs turning by moving a tool and a rotating workpiece relative to each other along a feeding direction, the tool stand on which the tool is attached, and the attached workpiece. The workpiece is turned by varying the relative movement speed between the rotating workpiece spindle, the feed shaft that moves the tool stand and the workpiece spindle relative to each other along the feed direction, and the tool stand and the workpiece spindle at a set oscillation frequency. a control device that sets a swing frequency different from the rotation frequency of the workpiece spindle and operates a feed shaft section at the swing frequency when a command for swing turning processing is received. Machinery provided.

According to the machine tool according to the first aspect of the present invention, the control device operates the feed shaft portion at a swing frequency different from a value obtained by multiplying the rotation frequency of the spindle by the number of teeth of the rotary tool, thereby controlling the spindle and the table. The workpiece can be machined by varying the relative movement speed with the set oscillation frequency. In such swing hole machining, the locus of the rotary tool fluctuates, and the thickness of chips produced by machining fluctuates. For this reason, the thinned portion becomes brittle, and the chips are divided from this point as a starting point. Further, since the oscillation frequency is set by the control device, there is no need for the operator to calculate and set it according to a wide variety of processing conditions, and an increase in the number of work steps can be suppressed.

Further, according to the machine tool according to one aspect of the present invention, the control device operates the feed shaft section at a swing frequency different from the rotation frequency of the workpiece spindle, thereby increasing the relative movement speed between the tool stand and the workpiece spindle. It is possible to turn a workpiece by varying the set oscillation frequency. In such oscillating turning, the locus of the tool changes, and the thickness of chips produced by oscillating turning changes. For this reason, the thinned portion becomes brittle, and the chips are divided from this point as a starting point. Further, since the oscillation frequency is set by the control device, there is no need for the operator to calculate and set it according to a wide variety of processing conditions, and an increase in the number of work steps can be suppressed.

FIG. 1 shows a side view of a hole machining machine tool according to a first embodiment. FIG. 2 shows an example of a database provided in the control device according to this embodiment. FIG. 3 shows the locus of the cutting edge operated at the fundamental frequency according to this embodiment. FIG. 4 shows the locus of the cutting edge when the swing frequency matches the product of the rotational frequency of the spindle and the number of cutting edges of the rotary tool. FIG. 5 shows the locus of the cutting edge operated at the thinnest part forming frequency according to this embodiment. FIG. 6 shows the locus of the cutting edge operating at the short piece forming frequency according to this embodiment. FIG. 7 shows a flowchart from data input to start of hole machining using the machine tool according to the present embodiment. FIG. 8 shows a block diagram when a control device according to a modification of the present embodiment is connected to a machine tool via a network. FIG. 9 shows a side view of a turning machine tool according to the second embodiment.

Hereinafter, a machine tool according to an embodiment will be described with reference to the accompanying drawings. Similar or corresponding elements are denoted by the same reference numerals, and redundant explanations will be omitted. In order to facilitate understanding, the scale of figures may be changed for explanation.

(First embodiment)
FIG. 1 shows an example of a machine tool according to the first embodiment. The machine tool 100 constitutes a vertical machining center, and includes a bed 102 as a base fixed to the floor of a factory. Further, the upper surface of the bed 102 can be moved in the left-right direction, that is, on the left side in the Y-axis direction (the left side in FIG. 1), in the front-back direction, that is, in the X-axis direction (perpendicular to the plane of the paper in FIG. 1) or in the Y-axis direction. A table 106 is arranged on which a workpiece W as a workpiece is fixed, and a column 104 is fixed and erected on the upper surface of the bed 102 on the right side of the bed 102 in the Y-axis direction (right side in FIG. 1). . Further, on the front side of the column 104, that is, on the left side in the Y-axis direction, there is an X-axis slider 108 that is configured to be movable along the The spindle head 110 is attached to be movable along the spindle and rotatably supports the spindle 112.

The column 104 includes an X-axis feed device as a feed shaft portion for reciprocating the X-axis slider 108 along a pair of X-axis guide rails (not shown) extending in the X-axis direction on the front surface of the column 104. 114 are arranged. The X-axis feed device 114 includes a ball screw that extends in the X-axis direction and engages with a nut attached to the X-axis slider 108, and an X-axis servo motor connected to one end of the ball screw. (also not shown). Thereby, the X-axis slider 108 is configured to be able to reciprocate along the X-axis direction on the front surface of the column 104.

The bed 102 includes a Y-axis feed device 116 as a feed shaft portion for reciprocating the table 106 along a pair of Y-axis guide rails (not shown) extending in the Y-axis direction on the upper surface of the bed 102. It is located. The Y-axis feed device 116 includes a ball screw that extends in the Y-axis direction and engages with a nut attached to the table 106, and a Y-axis servo motor connected to one end of the ball screw (both are not shown). omission). Thereby, the table 106 is configured to be able to reciprocate along the Y-axis direction on the upper surface of the bed 102.

The spindle head 110 supports a spindle 112 rotatably around a central axis O extending along the Z-axis direction. A rotary tool T1 is attached to the tip of the main shaft 112 facing the table 106. Here, a drill with two blades is installed as the rotary tool T1. Furthermore, a servo motor (not shown) for rotationally driving the main shaft 112 is attached to the outer side of the casing of the main spindle head 110. In the following description, the servo motor will be described as being attached to the outside of the spindle head 110, but the servo motor is not limited to this. It may be a built-in motor configured by Moreover, although the rotary tool T1 is described here as a drill, the rotary tool is not limited to this, and other tools such as a boring cutter, a counterbore cutter, a reamer, and a boring tool may be used as the rotary tool.

The column 104 includes a Z-axis feeding device as a feed shaft portion for reciprocating the spindle head 110 along a pair of Z-axis guide rails (not shown) extending in the Z-axis direction on the front side of the column 104. 118 are arranged. The Z-axis feed device 118 includes a ball screw that extends in the Z-axis direction and engages with a nut attached to the spindle head 110, and a Z-axis servo motor connected to one end of the ball screw. (not shown). Thereby, the spindle head 110 is configured to be able to reciprocate along the Z-axis direction on the front side of the column 104.

The X-axis feed device 114, the Y-axis feed device 116, and the Z-axis feed device 118 are connected to the control device 10 for controlling the machine tool 100. The control device 10 controls the reciprocation of the spindle head 110 and the table 106 by controlling the power (current value) supplied to the X-axis feed device 114, the Y-axis feed device 116, and the Z-axis feed device 118, As a result, the relative movement speed between the main shaft 112 and the table 106 is controlled.

The control device 10 reads and interprets a machining program (NC program) stored in, for example, a CAM (Computer Aided Manufacturing) system (not shown), and outputs an operation command. The NC program is automatically generated based on machining model information and machining conditions input into the CAM system.

The control device 10 has a storage for storing various data related to machining such as machining conditions and tools for oscillating hole machining in which a hole is machined while oscillating. A database DB has been constructed. The control device 10 refers to a database DB as shown in FIG. 2 to determine the swing frequency fv, which will be described below, based on the conditions regarding swing hole machining inputted from the input unit 10a such as a touch panel, for example. Calculate and output reciprocating motion command. The conditions for reciprocating operation include the material of the work W, the diameter and depth of the hole to be machined, the feed rate of the tool, the rotation speed of the rotary tool T1 (spindle 112), the number of teeth, and the type of tool such as a drill or counterbore tool. etc. are included. The control device 10 is configured to cumulatively store past reciprocating operation conditions in a database DB.

The control device 10 has a tool data management section 10c. As a result, if there is no instruction for the number of blades of the rotary tool T1 in the NC program, the control device 10 sets the number of blades by referring to the number of blades in the tool data management section 10c. Further, if there is no data on the number of blades in the tool data management unit 10c, the number of blades is set to two, for example, since a drill is generally configured with two blades. The number of blades set in this way is used as an input for calculating the swing frequency fv. Note that the tool data management section may be configured to be linked to a database.

The control device 10 further includes a controller for driving the X-axis feed device 114, Y-axis feed device 116, and Z-axis feed device 118 of the machine tool 100 based on the output X-axis, Y-axis, and Z-axis position commands. A current value is output and sent to a drive device such as a servo motor installed in these devices. When machining a swing hole, the current value output to the X-axis feed device 114, Y-axis feed device 116, and Z-axis feed device 118 is adjusted to a predetermined swing amplitude AM and a swing value in order to swing these devices. It is output as a periodically fluctuating current value determined by the frequency.

Displacement Zk in the central axis direction of the main shaft 112 of the cutting edge of the rotary tool T1 operated at the swing frequency, here the Z-axis direction, is expressed as a function of the tool rotation angle (tool phase) θ as follows. Further, the displacement Zk is positive in the direction in which the rotary tool T1 and the workpiece W approach.
Zk(θ)=AM・sin{fv・φ/fd}+Fz・n・φ/2π (1)
φ=θ−2πk/n (2)
Here, k is the number of rotations of the rotary tool T1, Fz is the feed per tooth, fd is the rotation frequency of the rotary tool T1, n is the number of teeth of the rotary tool T1, fv is the swing frequency, AM is the swing amplitude, π represents pi. As mentioned above, Zk(θ) is the relative displacement in the Z-axis direction between the outer periphery of the cutting edge of the rotary tool T1 and the work W when vibration with the swing amplitude AM and the swing frequency fv is applied in the Z-axis direction. The displacement in the first term and the displacement in the second term of equation (1) respectively represent a fluctuating portion and a steady portion due to shaft feeding.

Here, the fundamental oscillation frequency fv (hereinafter referred to as fundamental frequency fb) for producing a difference in chip thickness is expressed as follows.
fb=fd・n/2 (3)
As derived by substituting equations (2) and (3) into equation (1), the swing amplitude AM of the rotary tool T1 swinging at the fundamental frequency fb is determined by the position relative to the tool rotation angle θ. It fluctuates with the phase difference π.

FIG. 3 shows the trajectories of the cutting edges of the first blade A and the second blade B in swing hole machining in which a rotary tool T1 having two blades is swung along the Z-axis direction at a fundamental frequency fb. The vertical axis in the figure represents the displacement Zk in the Z-axis direction, and the horizontal axis represents the tool phase θ. "-1", "-2" and "-3" in the legend in the figure represent the first to third rotations of the rotary tool T1, respectively. Therefore, for example, "A-1" means the trajectory of the first blade A in its first rotation. Further, the difference in the displacement Zk of the first blade A and the second blade B in the Z-axis direction at the same tool phase θ means the thickness TH of chips cut from the workpiece W by hole drilling. Since there is a phase by π, the difference in displacement Zk in the Z-axis direction between the first blade A and the second blade B fluctuates as shown in FIG. A thin portion TH-MIN is generated. In this way, each rotation of the rotary tool T1 generates one portion TH-MIN where the chips are the thinnest, so the chips are more likely to be broken up.

As a comparison with swing hole machining at the basic frequency fb, FIG. Shows the trajectory of the cutting edge when swinging. Since there is no phase difference between the first blade A and the second blade B, the thickness TH of the chips is always constant, and the chips are not easily divided. Therefore, it is understood that the swing frequency fv needs to be set to a frequency different from the frequency found by multiplying the rotation frequency fd of the rotary tool T1 and the number n of blades of the rotary tool.

In addition, if the control device 10 wants to make the thinnest part TH-MIN of chips even thinner, the control device 10 can calculate the thinnest part forming frequency fm instead of the fundamental frequency fb and set it as the oscillation frequency fv. can. The thinnest part forming frequency fm is calculated by multiplying the fundamental frequency fb by a first coefficient smaller than 1. The first coefficient may be set in advance in the NC program, or may be set with reference to the database DB. FIG. 5 shows an example of the trajectory of the cutting edges of the first blade A and the second blade B when the rotary tool T1 having two blades is oscillated along the Z-axis direction at the thinnest part forming frequency fm. shows. Here, the thinnest part forming frequency fm is set to about half the fundamental frequency fb, with the first coefficient being about 0.5. The vertical axis, horizontal axis, and legend in the figure are the same as in FIG. 3. Compared to the case of swinging at the fundamental frequency fb, the thinnest portion TH-MIN of the chip thickness TH can be made thinner. On the other hand, the length of the chips becomes longer than in the case of swinging at the fundamental frequency fb.

Further, when the control device 10 wants to shorten the length of the chips and divide them into small pieces, the control device 10 can calculate the short piece forming frequency fs instead of the basic frequency fb and set it as the swing frequency fv. The short piece forming frequency fs is calculated by multiplying the fundamental frequency fb by a second coefficient that is larger than 1 and is a non-even number. The second coefficient may be set in advance in the NC program, or may be set with reference to the database DB. FIG. 6 shows an example of the trajectory of the cutting edges of the first blade A and the second blade B when the rotary tool T1 having two blades is oscillated along the Z-axis direction at the short piece forming frequency fs. . Here, the short piece forming frequency fs is set to about three times the fundamental frequency fb, with the second coefficient being about 3.0. The vertical axis, horizontal axis, and legend in the figure are the same as in FIGS. 3 and 5. The length of chips can be shortened compared to the case of swinging at the fundamental frequency fb. On the other hand, the thinnest portion TH-MIN of the chips becomes thicker than when the chips are oscillated at the fundamental frequency fb.

If the calculated swing frequency fv exceeds the upper limit of the frequency at which the X-axis feed device 114, the Y-axis feed device 116, and the Z-axis feed device 118 can be rocked (upper limit swing frequency), the control device 10 is configured to set this upper limit swing frequency as the swing frequency fv. Depending on the relatively moving workpiece W and the weight of these devices 114, 116, 118, it may be difficult to repeat acceleration and deceleration at a high frequency, that is, in a short period, so the control device 10 sets the upper limit swing frequency. Configurable. When oscillating at the upper limit oscillation frequency, the length of the chips will be longer than when machining at the calculated oscillation frequency fv, but there will be parts where the chips become thinner at regular intervals. , chips can be separated.

The control device 10 controls, for each machine tool 100, a fundamental frequency fb, a first coefficient related to the thinnest part forming frequency fm, a second coefficient related to the short piece forming frequency fs, a basic mode corresponding to the fundamental frequency fb, and a first coefficient. It has a mode storage section 10b that stores the thinnest part forming mode corresponding to the coefficient and the short piece forming mode corresponding to the second coefficient. The operator can select a mode according to the machining, and the control device 10 can select or calculate the swing frequency fv corresponding to the selected mode, and control the swing hole machining based on this. can. The operator can machine the swing hole at the swing frequency fv according to the mode without individually setting the basic frequency fb, the first coefficient, and the second coefficient, reducing the number of work steps. . The mode to be selected depending on the processing may be selected from the three modes described above, or an interface may be provided that allows selection from more modes including an intermediate mode between each mode. The mode selection may be performed each time using the NC program, or may be predetermined using machine parameters.

The control device 10 is configured to automatically change the second coefficient related to the short piece forming frequency fs to an odd number when it is set to an even number. Thereby, even if the operator mistakenly sets the second coefficient, it is possible to obtain the effect of appropriately dividing chips.

The effects of the machine tool 100 according to this embodiment will be explained below along with the flowchart shown in FIG.

The swing hole machining is performed by operating the machine tool 100 by executing a program stored in the control device 10. First, in step S10, the control device 10 calls the swing hole machining program in the machining program, and obtains information on the rotational frequency fd and the number of blades n from arguments and the state of the device. Specifically, for example, G81X_Y_Z_R_F_S_E_H_ is written in the machining program. Here, G81 is the G code used in the NC (numerical control unit) machining program, X is the X coordinate of the center of the hole, Y is the Y coordinate of the center of the hole, Z is the distance from the R point to the bottom of the hole in the Z coordinate, R is the position at which rapid traverse positioning shifts to cutting feed in the Z coordinate, S is the rotation speed of the spindle 112, E is the number of teeth n of the rotary tool T1, and H is the frequency when changing the thinness and length of chips. Indicates the coefficient for increasing or decreasing. Since the rotation speed of the main shaft 112 indicated by S indicates the number of rotations of the main shaft per minute, the rotation frequency fd can be obtained by dividing this by 60. In the program that commands swing hole machining, the rotation frequency fd may be directly indicated in S. If S is omitted, the last commanded S code or rotational frequency fd is referred to. Furthermore, if E is omitted, the tool data is referred to, and if there is no value there, n=2 is assumed. Furthermore, if H is omitted, it is set to 1.

Next, in step S20, one of the fundamental frequency fb, the thinnest part forming frequency fm, or the short piece forming frequency fs is determined from the acquired information on the rotational frequency fd, the number of blades n, the first coefficient, or the second coefficient. Calculate the dynamic frequency fv.

Next, in step S30, it is determined whether the calculated swing frequency fv exceeds the upper limit swing frequency at which the X-axis feed device 114, Y-axis feed device 116, and Z-axis feed device 118 can be swung. Determine whether If the swing frequency fv does not exceed the upper limit swing frequency, the process moves to step S40, and swing hole machining is started at the calculated swing frequency fv. On the other hand, if the swing frequency fv exceeds the upper limit swing frequency, the upper limit swing frequency is set to the swing frequency fv in step S50, and swing hole machining is started. In this embodiment, the hole is machined by moving the spindle in the Z direction, so the determination can be made using the upper limit swing frequency set based on the characteristics of the Z-axis feeder 118. When drilling in the direction, the determination can be made using the upper limit swing frequency set based on the characteristics of the X-axis feed device 114 and the Y-axis feed device 116.

According to the machine tool 100 according to the present embodiment, the control device 10 controls the Z-axis feed at a swing frequency fv (basic frequency fb) that is different from a value obtained by multiplying the rotational frequency fd of the spindle 112 by the number n of teeth of the rotary tool T1. By operating the device 118, the relative movement speed between the main shaft 112 and the workpiece W can be varied at the fundamental frequency fb to perform swing hole machining. In such swing hole machining, the locus of the rotary tool T1 fluctuates, and the thickness TH of chips produced by machining fluctuates. Therefore, the thinned portion TH-MIN becomes brittle, and the chips are divided from this as a starting point. Further, since the fundamental frequency fb is set by the control device 10, there is no need for the operator to calculate and set it according to a wide variety of processing conditions, and an increase in the number of work steps can be suppressed.

Further, according to the machine tool 100 according to the present embodiment, the relative movement speed between the main spindle 112 and the workpiece W can be varied within a range where the main spindle 112 or the table 106 are not separated along the Z-axis direction. Therefore, the rotary tool T1 does not retreat in the Z-axis direction, and the tip of the rotary tool T1 always remains in contact with the work W and does not separate from the work W. Therefore, it is possible to suppress or prevent the cutting edge of the rotary tool T1 from chipping and the generation of noise that may occur when the rotary tool T1 collides with or separates from the workpiece W. Furthermore, since there is no operation such as stopping or retreating along the Z-axis direction, it is possible to suppress or prevent the occurrence of a phenomenon in which machining time becomes longer, which may occur as a problem in the drill cycle. Furthermore, since the moving distance does not increase due to reciprocating motion, there is no adverse effect on the life of the feed shaft device.

Further, according to the machine tool 100 according to the present embodiment, the control device 10 multiplies the fundamental frequency fb by a first coefficient smaller than 1 when it is desired to make the thinnest portion TH-MIN of chips thinner. The thinnest part formation frequency fm can be calculated and set using the following steps. As a result, the thinnest portion TH-MIN of the chip thickness TH can be made thinner than in the case of swinging at the fundamental frequency fb.

Further, according to the machine tool 100 according to the present embodiment, when the length of the chips is shortened and the chips are to be finely divided, the control device 10 sets the fundamental frequency fb to a second frequency higher than 1 and a non-even number. The short piece formation frequency fs can be calculated and set by multiplying by the coefficient. This makes it possible to shorten the length of chips compared to the case of swinging at the fundamental frequency fb.

Furthermore, according to the machine tool 100 according to the present embodiment, when the calculated swing frequency fv exceeds the upper limit swing frequency at which the Z-axis feed device 118 can swing, the control device 10 controls the The upper limit swing frequency can be set as the swing frequency fv. As a result, although the length of the chips becomes longer than when machining is performed at the calculated oscillation frequency fv, parts where the chips become thinner occur at regular intervals, so the chips can be divided.

Further, according to the machine tool 100 according to the present embodiment, the control device 10 includes a mode storage section 10b and a database DB. The operator can select a mode according to the machining, and the control device 10 can calculate the swing frequency fv from the coefficient corresponding to the selected mode, and control the swing hole machining based on this. can. As a result, the operator can machine the swing hole at the swing frequency fv according to the mode without individually setting the basic frequency fb, the first coefficient, and the second coefficient, reducing the number of work steps. be able to.

As described above, when the machine tool 100 according to the present embodiment performs machining by periodically varying the relative speed between the rotary tool T1 and the workpiece W, the oscillation frequency fv at which the chip breaking effect can be obtained is automatically set. Can be set to .

(Modified example)
Hereinafter, a machine tool 100 according to a modification will be described using FIG. 8. Elements similar to or corresponding to those in the first embodiment are given the same reference numerals, and redundant explanations will be omitted.

According to the machine tool 100 according to this modification, the control device 10 is connected to the machine tool 100 via the network NW. Therefore, the control device 10 can swing the X-axis feed device 114, the Y-axis feed device 116, and the Z-axis feed device 118 of the machine tool 100 via the network NW. Thereby, a plurality of machine tools 100 can be centrally controlled.

In this embodiment, the rotary tool T1 is oscillated along the Z-axis direction at the fundamental frequency fb, but the present invention is not limited to this. It is also possible to perform rocking processing by moving it.

(Second embodiment)
The machine tool 200 according to the second embodiment will be described below with reference to FIG. Elements similar to or corresponding to those in the first embodiment are given the same reference numerals, and redundant explanations will be omitted.

The machine tool 200 according to the second embodiment is a machine tool 200 that performs turning by relatively moving a tool T2 and a rotating workpiece W along the feeding direction, and includes a tool stand 212 on which the tool T2 is attached, A workpiece main shaft 206 that rotates the attached workpiece W is provided. The machine tool 200 also includes an X-axis feeder 114 and a Y-axis, which serve as feed shaft sections that relatively move the tool stand 212 and the workpiece spindle 206 along the X-axis direction, Y-axis direction, and Z-axis direction, which are the feeding directions. It includes a feeding device 116 and a Z-axis feeding device 118 (hereinafter referred to as devices 114, 116, and 118). Furthermore, when the machine tool 200 receives a command for oscillating turning in which the workpiece W is turned by varying the relative movement speed between the tool stand 212 and the workpiece spindle 206 at a set oscillation frequency fv, the machine tool 200 A control device 20 is provided which sets a swing frequency fv different from the rotation frequency fd of 206 and operates the devices 114, 116, and 118 at the swing frequency fv.

According to the machine tool 200 according to the second embodiment, the control device 20 operates the tool stand 212 and the workpiece spindle by operating the devices 114, 116, and 118 at a swing frequency fv different from the rotation frequency fd of the workpiece spindle 206. The workpiece W can be turned by varying the relative movement speed with the set swing frequency fv. In such an oscillating turning process, the locus of the tool T2 changes, and the thickness TH of chips produced by the oscillating turning process changes. Therefore, the thinned portion TH-MIN becomes brittle, and the chips are divided from this as a starting point. Further, since the swing frequency fv is set by the control device 20, there is no need for the operator to calculate and set it according to a wide variety of processing conditions, and an increase in the number of work steps can be suppressed.

Although the embodiments of the machine tools 100 and 200 have been described above, the present invention is not limited to the above embodiments. Those skilled in the art will appreciate that various variations of the embodiments described above are possible.

10 Control device 20 Control device 100 Machine tool 106 Table 112 Main spindle 114 X-axis feed device (feed shaft part)
116 Y-axis feed device (feed shaft part)
118 Z-axis feed device (feed shaft part)
200 Machine tool 206 Work spindle 212 Tool stand DB Database fv Oscillation frequency fb Fundamental frequency fm Thinnest part forming frequency fs Short piece forming frequency T1 Rotary tool T2 Tool

Claims (10)

A machine tool that processes holes by moving a rotary tool and a workpiece relative to each other,
a main shaft for rotating the attached rotary tool;
a table on which the workpiece is attached;
a feed shaft portion that relatively moves the main spindle and the table along the central axis direction of the main spindle;
When receiving a command for oscillating hole machining in which the relative movement speed between the main spindle and the table is varied at a oscillation frequency to form a hole in the workpiece, multiplying the rotational frequency of the main spindle by the number of teeth of the rotary tool. a control device that sets a rocking frequency different from the value set and operates the feed shaft section at the rocking frequency;
A machine tool characterized by comprising: The machine tool according to claim 1, wherein the relative movement speed between the spindle and the table varies within a range where the spindle or the table is not separated along the central axis direction of the spindle. A machine tool that performs turning by relatively moving a tool and a rotating workpiece along the feed direction,
a tool stand on which the tool is attached;
a workpiece spindle that rotates the attached workpiece;
a feed shaft portion that relatively moves the tool stand and the workpiece spindle along the feed direction;
When receiving a command for oscillating turning processing in which the relative movement speed between the tool stand and the workpiece spindle is varied at a oscillation frequency to turn the workpiece, a oscillation frequency that is different from the rotational frequency of the workpiece spindle is received. a control device that sets the oscillation frequency and operates the feed shaft section at the oscillation frequency;
A machine tool characterized by comprising: The machine tool according to claim 3, wherein the relative movement speed between the tool stand and the workpiece spindle varies within a range where the tool stand or the workpiece spindle are not separated along the feeding direction. The machine tool according to any one of claims 1 to 4, wherein the oscillation frequency is a fundamental frequency that is a product of the rotation frequency, the number of teeth, and 0.5. The machine tool according to claim 5, wherein the oscillation frequency is a thinnest part forming frequency obtained by multiplying the fundamental frequency by a first coefficient smaller than 1. The machine tool according to claim 5, wherein the oscillation frequency is a short piece forming frequency obtained by multiplying the fundamental frequency by a second coefficient that is larger than 1 and is not an even number. According to any one of claims 1 to 7, when the set rocking frequency exceeds an upper limit value of a frequency at which the feed shaft portion can be operated, the feed shaft portion is operated at the upper limit value. Machine tools listed. The machine tool according to any one of claims 1 to 8, wherein the control device has a database for associating the workpiece and machining information with the oscillation frequency. The machine tool according to any one of claims 1 to 9, wherein the control device operates the feed shaft section via a network.

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