Machine tool control device

Abstract

The present invention provides a control device for a machine tool, which can perform thread cutting while reducing the burden on the machine tool caused by the swing action without extending the cycle time, and can effectively crush the chips when the non-swinging action of the current path is performed after the swing action of the previous path. The control device for the machine tool comprises: a swing action execution determination unit, which determines whether to perform a swing action that causes the cutting tool to swing in the radial direction of the workpiece; a swing instruction generation unit, which generates a swing instruction according to the determination result; and a control unit, which generates a drive instruction by overlapping the swing instruction with the position instruction of the feed axis, the swing action execution determination unit determines that the swing action is performed intermittently, and the swing instruction generation unit generates the swing instruction so that the non-swinging cutting processing part of the current path includes the swinging cutting processing completed part of the previous path, or the swinging cutting processing part of the current path includes the non-swinging cutting processing completed part of the previous path.

Description

Technical Field

[0001] The invention relates to a control device for a machine tool. Background Art

[0002] At present, there is a known technique for performing thread cutting while crushing the chips. For example, during a predetermined multiple cutting process, the workpiece and the cutting tool are reciprocated and vibrated, and the vibration mode during each cutting process accompanied by the reciprocating vibration is set so that the cutting process portion during the predetermined cutting process partially includes the portion that has been cut by other cutting processes (for example, refer to Patent Document 1).

[0003] However, in the technology of Patent Document 1, since the reciprocating vibration (hereinafter also referred to as swinging motion) between the workpiece and the cutting tool is always performed during the thread cutting process, the reciprocating vibration places a heavy burden on the machine tool. Therefore, a control device for a machine tool is desired, which can perform thread cutting while reducing the burden on the machine tool caused by the swinging motion without extending the important cycle time during the processing of the machine tool.

[0004] In addition, in the technology of Patent Document 1, due to response delay and the like, the deviation between the position command and the actual position, i.e., the position deviation, is large during the swing operation, thereby causing incomplete cutting (see the following description). Figure 7 ). Therefore, it is currently difficult to achieve chip crushing in the final path finish machining, and a machine tool control device is desired that can effectively crush the chips when performing a non-swinging action of the current path after the swinging action of the previous path, such as in the final path finish machining of thread cutting.

[0005] Patent Document 1: International Publication No. 2016 / 056526 Summary of the invention

[0006] One embodiment of the present disclosure is a control device for a machine tool, which causes at least one main shaft and at least one feed shaft to cooperate with each other, and performs thread cutting processing while a cutting tool cuts into a workpiece multiple times in a radial direction. The at least one main shaft causes the cutting tool to rotate relative to the workpiece, and the at least one feed shaft causes the cutting tool to move relative to the workpiece. The control device for the machine tool includes: a swing action execution determination unit, which determines whether to execute a swing action for causing the cutting tool to swing in the radial direction of the workpiece; a swing instruction generation unit, which generates a swing instruction for the swing action based on a determination result of the swing action execution determination unit; and a control unit, which generates a drive instruction for the feed shaft by superimposing the swing instruction on a position instruction of the feed shaft, the swing action execution determination unit determines that the swing action is to be executed intermittently, and the swing instruction generation unit generates a swing instruction so that a non-swing cutting processing portion in this cutting action includes a swing cutting processing completed portion in a previous cutting action, or so that a swing cutting processing portion in this cutting action includes a non-swing cutting processing completed portion in a previous cutting action.

[0007] According to the present disclosure, a control device for a machine tool can be provided, which can perform thread cutting while reducing the burden on the machine tool caused by the swinging action without extending the cycle time. In addition, a control device for a machine tool can be provided, which can effectively cut chips when a non-swinging action is performed in this path after a swinging action in the previous path, such as finishing in the final path of the thread cutting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a functional block diagram showing the structure of a control device for a machine tool according to one embodiment of the present disclosure.

[0009] Figure 2 Indicates screws made by thread cutting.

[0010] Figure 3 Represents a workpiece in thread cutting processing.

[0011] Figure 4 The following is used to explain the operation of thread cutting performed by a control device for a machine tool according to one embodiment of the present disclosure.

[0012] Figure 5 The following is used to explain the operation of thread cutting performed by a control device for a machine tool according to one embodiment of the present disclosure.

[0013] Figure 6 The following is used to explain the operation of thread cutting performed by a control device for a machine tool according to one embodiment of the present disclosure.

[0014] Figure 7Represents the finishing in the final pass of an existing thread cutting operation.

[0015] Figure 8 The following shows finishing in the final path of thread cutting performed by a control device for a machine tool according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0016] Hereinafter, one embodiment of the present disclosure will be described in detail with reference to the drawings.

[0017] The control device of a machine tool of one embodiment of the present invention enables at least one main shaft and at least one feed shaft to cooperate with each other, and performs thread cutting processing by cutting into the workpiece multiple times in the radial direction through the cutting tool. The at least one main shaft causes the cutting tool and the workpiece to rotate relative to each other, and the at least one feed shaft causes the cutting tool to move relative to the workpiece.

[0018] Figure 1 1 is a functional block diagram showing the structure of a control device 100 for a machine tool according to one embodiment of the present disclosure. Figure 1 As shown, the control device 100 outputs a drive command for driving the motor 120 for driving at least one spindle and at least one feed axis to make these axes work in coordination. The at least one spindle causes the cutting tool and the workpiece to rotate relative to each other, and the at least one feed axis causes the cutting tool to move relative to the workpiece.

[0019] Before describing the structure of the control device 100, Figure 2 and Figure 3 Here, thread cutting is explained. Figure 2 The figure shows a screw 12 manufactured by thread cutting. Figure 3 A workpiece 14 is shown during a thread cutting process.

[0020] like Figure 2 As shown, the screw 12 made by thread cutting has a thread groove 10 of sufficient depth formed spirally on its outer peripheral surface. The control device 100 of the machine tool of one embodiment of the present invention makes the cutting tool and the workpiece rotate relative to each other, and makes the cutting tool move relative to the workpiece to perform cutting, thereby forming the thread groove 10.

[0021] like Figure 3 As shown by arrow P in FIG. 1 , the cutting tool 16 performs cutting processing on the thread groove 10 of the workpiece 14 multiple times on a predetermined trajectory 10a (i.e., the position of the thread groove 10) on the workpiece 14. The trajectory 10a exists in a spiral shape on the entire outer peripheral surface of the workpiece 14. Figure 3 This is the state where the cutting process has just started, and the depth of the thread groove 10 is still shallow. Figure 2 The deep thread groove 10 is shown, and the final screw 12 is completed.

[0022] exist Figure 3 In the embodiment, the workpiece 14 is mounted on the spindle 18 and is controlled to rotate in the rotation direction indicated by the arrow C. The rotation coordinate axis indicated by the arrow C is referred to as the C axis. That is, the C axis is an angular coordinate indicating an angle around the spindle 18.

[0023] The cutting tool 16 moves on the trajectory 10a on the surface of the rotating workpiece 14 to cut the thread groove 10. Therefore, the cutting tool 16 is controlled to move along the Z axis, which is the longitudinal coordinate axis of the workpiece 14, in synchronization with the rotation of the workpiece 14 in the C axis direction.

[0024] In addition, the cutting tool 16 gradually moves in the direction perpendicular to the surface of the workpiece 14, that is, in the X-axis direction which is a radial coordinate axis, during each cutting process. Therefore, the cutting tool 16 is controlled to perform cutting process at a gradually deeper position relative to the workpiece 14.

[0025] Next, the structure of the control device 100 of the machine tool according to one embodiment of the present disclosure will be described. Figure 1 As shown, the control device 100 includes a swing operation execution determination unit 102 , a swing condition calculation unit 104 , a swing instruction generation unit 106 , an adder 108 , and a control unit 110 .

[0026] For example, a numerical controller is used as the control device 100. The control device 100 is realized by causing a computer including a CPU, a memory, etc. to read the program of the present embodiment.

[0027] The swinging action execution determination unit 102 determines whether to execute a swinging action that causes the cutting tool 16 to swing in the radial direction (X-axis direction) of the workpiece 14. This determination is performed based on a machining program input from the outside. The swinging action execution determination unit 102 of one embodiment of the present disclosure is characterized in that it determines whether the swinging action is executed intermittently. That is, the swinging action execution determination unit 102 determines the execution of the intermittent swinging action, so that the swinging action that causes the cutting tool 16 and the workpiece 14 to reciprocate relative to each other and the non-swinging action that does not perform the reciprocating vibration are repeated alternately. Thus, within the same machining path, the swinging action and the non-swinging action are repeated alternately.

[0028] Preferably, the swing operation execution determination unit 102 determines the execution of the swing operation so that the swing cutting process is performed at a position different from the swing cutting process completed portion in the previous swing operation in the current cutting operation. As a result, the previous cutting process completed portion can be more reliably included in the current cutting process, so that the so-called empty swing is reliably generated, and the chip breaking becomes more reliable.

[0029] In addition, it is preferred that the swinging motion execution determination unit 102 determines that after the cutting based on the swinging motion is intermittently performed, the cutting without the swinging motion is performed in the next path. Thus, for example, when non-swinging cutting is performed in the final path after the swinging cutting is performed, the chips can be reliably cut. This will be described in detail later.

[0030] In addition, it is preferred that the swinging motion execution determination unit 102 determines that the non-swinging cutting process is performed in the non-swinging cutting process portion based on the intermittent swinging motion until the deviation between the position command and the actual position, i.e., the position deviation, becomes less than a predetermined threshold value. Thus, in the non-swinging cutting process portion based on the intermittent swinging motion, the chips can be reliably cut. This will be described in detail later.

[0031] The swing condition calculation unit 104 calculates the swing operation condition output to the swing instruction generation unit 106 based on at least one of the machining program, machining parameters, and feedback values ​​from the machine tool. Figure 1 As shown, the swing condition calculation unit 104 calculates the interval of the swing operation (described later) based on the machining program input from the outside. Figure 4 The distance between adjacent vertices in the swing waveform shown), amplitude, period and other conditions.

[0032] Preferably, the swing condition calculation unit 104 changes the interval of the swing action. More specifically, the swing condition calculation unit 104 may change the interval of the swing action between different processing paths. In addition, the swing condition calculation unit 104 may also change the interval of the swing action within the same processing path. Alternatively, the swing condition calculation unit 104 may change the interval of the swing action between different processing paths and change the interval of the swing action within the same processing path.

[0033] In addition, the swing condition calculation unit 104 may also change the interval of the swing action according to the diameter of the workpiece 14. For example, the smaller the diameter of the workpiece 14 becomes, that is, the more the number of cutting processes increases, the longer the interval of the swing action is. Alternatively, on the contrary, the smaller the diameter of the workpiece 14 becomes, that is, the more the number of cutting processes increases, the shorter the interval of the swing action is. The interval setting of the swing action will be described in detail later.

[0034] The swing instruction generation unit 106 generates a swing instruction for the swing action according to the determination result of the swing action execution determination unit 102. In addition, the swing instruction generation unit 106 generates a swing instruction for the swing action according to the swing condition calculated by the swing condition calculation unit 104. The swing instruction generation unit 106 of one embodiment of the present disclosure generates a swing instruction so that the non-swing cutting processing part in this cutting action includes the swing cutting processing completed part in the previous cutting action. Alternatively, the swing instruction generation unit 106 generates a swing instruction so that the swing cutting processing part in this cutting action includes the non-swing cutting processing completed part in the previous cutting action. Thereby, the so-called empty swing can be generated more effectively, and the chip cutting can be performed more effectively.

[0035] Adder 108 calculates a position deviation, which is a difference between position feedback obtained by position detection of an encoder (not shown) provided in motor 120 and a position command of the feed axis. The position command of the feed axis and the position deviation are input to control unit 110 described later.

[0036] The control unit 110 generates a drive command for the motor 120 for driving the feed shaft by superimposing the swing command generated by the swing command generating unit 106 on the position command and position deviation of the feed shaft. In addition, in one embodiment of the present disclosure, the position command of the conveying shaft is temporarily generated, and the swing command is superimposed on the generated position command, but it is not limited to this, and the position command of the feed shaft may be generated by superimposing the swing command in advance.

[0037] Next, refer to Figures 4 to 6 The operation of thread cutting processing by the control device 100 of a machine tool according to one embodiment of the present disclosure will be described in detail. Figures 4 to 6 The following are used to explain the operation of thread cutting performed by the control device 100 of a machine tool according to one embodiment of the present disclosure. Figure 3 In more detail, Figure 4 An example is shown in which the intervals of the swing operations of each machining path (hereinafter referred to as a path) are fixed. Figure 5 This is an example in which the interval of the swinging operation is made longer as the diameter of the workpiece 14 is smaller. Figure 6 An example is shown in which the swinging motion of each path is not in a direction of cutting into the workpiece 14 but in a direction of moving away from the workpiece 14 .

[0038] In addition, by Figure 3 The same definition is used for the C-axis, Z-axis, and X-axis in Figures 4 to 6 In the C-axis, Z-axis and X-axis. Figures 4 to 6In the figure, the portion encircled by a dotted circle is a portion in this cutting process that includes the portion completed in the previous cutting process, indicating a portion where so-called idle swing occurs and the chips are broken into pieces.

[0039] exist Figure 4 In the example of operation shown, any one of the first to fourth paths performs intermittent oscillating motion, and linear non-oscillating cutting and curved deep-cut oscillating cutting are repeated alternately. Figure 4 The interval L of the swinging motion shown is set to be constant. As for the final path, since it is finish machining, it is only non-swinging cutting machining without swinging, and all becomes linear cutting machining.

[0040] Here, regarding the interval L of the swing action, that is, Figure 4 The distance between adjacent vertices in the swing waveform shown can be set according to the allowed chip length. The allowed chip length is set to a length that does not interfere with the cutting tool 16 during cutting. Thus, the chips can be broken up within a range that does not interfere with the cutting. The allowed chip length can be specified by a G code or a parameter, thereby specifying the interval L of the intermittent swing action.

[0041] exist Figure 5 In the example shown, Figure 4 Similarly, in the example of operation shown in FIG. 1 , any one of the first to fourth paths performs intermittent oscillation, and linear non-oscillation cutting and curved deep-cut oscillation cutting are repeated alternately. Figure 5 As shown, the intervals of the oscillating motions are made different between the first to fourth paths. As for the final path, since it is a finishing process, only non-oscillating cutting without oscillation is performed, and all the cutting processes become linear.

[0042] Specifically, as the diameter of the workpiece 14 becomes smaller, that is, as the cutting process progresses, the interval of the swinging action is set longer. Figure 5 As shown, the interval L2 of the swinging motion of the fourth path is set longer than the interval L1 of the swinging motion of the first path. Therefore, as the number of cutting operations increases, the circumference of the workpiece 14 becomes shorter, and the interval of the swinging motion is extended, thereby keeping the length of the chips constant.

[0043] exist Figure 6 In the example shown, Figure 4Similarly to the example of operation shown in the figure, any one of the first to fourth paths performs intermittent oscillation, and linear non-oscillation cutting and curved oscillation cutting are repeated alternately. Figure 4 In the same manner as in the example of operation shown in FIG. 1 , the interval L of the swinging operation is set to be constant. However, the swinging operation of any one of the first to fourth paths is not in the direction of cutting into the workpiece 14 but in the direction of moving away from the workpiece 14. Figure 4 or Figure 5 Compared with the action example, the swing direction is opposite.

[0044] Here, if Figure 4 and Figure 5 As shown in FIG. 1 , when performing a swinging action in the direction of cutting into the workpiece 14, in order to determine the swinging amplitude so that the cutting process of the next path includes the cutting process completed in the current path, since the cutting depth of the next path depends on the swinging amplitude of the current path, it is necessary to pre-read the processing program by the control device 100 such as a numerical control device. In contrast, Figure 6 By reversing the direction of the swing as in the illustrated operation example, the swing amplitude of the next path does not depend on the swing amplitude of the current path, so that the control device 100 such as a numerical controller does not need to read the machining program in advance.

[0045] Next, refer to Figure 7 and Figure 8 The finishing process in the final path of the thread cutting process performed by the control device 100 of the machine tool according to one embodiment of the present disclosure will be described in detail. Figure 7 Represents the finishing in the final pass of an existing thread cutting operation. Figure 8 The present invention discloses a finishing process in the final path of the thread cutting process performed by the control device 100 of the machine tool. Figure 3 The same definition is used for the C-axis, Z-axis, and X-axis in Figure 7 and Figure 8 In addition, Figure 8 The portion encircled by the dotted line in the figure is a portion of the current cutting process that includes the portion completed in the previous cutting process, indicating a portion where so-called idle swing occurs and the chips are broken into pieces.

[0046] In the conventional thread cutting process, when the cutting action without swinging in the final path is performed after the cutting action with swinging in the previous path of the final path, the thread cutting process is performed as follows. Figure 7As shown by the dotted line 72 in FIG. 1 , the chips should be chopped because there is a place where the processed part of the final path includes the processed part of the previous path of the final path (i.e., the place where the dotted line 72 overlaps with the straight line of the final path. The valley part of the dotted line 72 is the so-called idle swing part.). However, in reality, as Figure 7 As shown by the solid line 71 in FIG. 1 , the chips may not be cut into pieces because the machining part in the final path does not include the machining completed part in the previous path of the final path (i.e., the solid line 71 overlaps with the straight line of the final path). This is caused by the deviation between the position command and the actual position during the swing action, i.e., the position deviation.

[0047] In contrast, in one embodiment of the present disclosure, it is ideal that Figure 8 As shown by the dotted line 82 in FIG. 8 , the processing portion in the final path includes the processing completed portion in the previous path of the final path, which is actually the same as Figure 8 As shown by the solid line 81 in the figure and the dotted line surrounded by the circle, the chips are broken up where the processed part in the final path includes the processed part in the previous path of the final path. This is because by setting the swing action and the non-swing action in the same path, the position deviation converges during the non-swing action. As a result, the chips can be broken up reliably in the final path.

[0048] In addition, the period of the non-oscillating action can be determined simply by using a value predetermined by time or distance, or can be determined based on whether the position deviation is below a predetermined threshold value. In addition, in the above description, the finishing in the final path of the thread cutting process is described as an example, but it is not limited to this, and the same can be said for all cases in which a non-oscillating cutting action is performed in the next path after a cutting action with swing.

[0049] In summary, according to one embodiment of the present invention, the following effects are achieved.

[0050] (1) A control device 100 of a machine tool enables at least one spindle 18 and at least one feed axis to cooperate with each other, and performs thread cutting processing by cutting into a workpiece 14 multiple times in a radial direction (X direction) by a cutting tool 16. The at least one spindle 18 causes the cutting tool 16 to rotate relative to the workpiece 14, and the at least one feed axis causes the cutting tool 16 to move relative to the workpiece 14. The machine tool control device 100 is provided with: a swing action execution determination unit 102, which determines whether to execute a swing action of causing the cutting tool 16 to swing in a radial direction (X direction) of the workpiece 14; a swing instruction generation unit 106, which generates a swing instruction for the swing action based on the determination result of the swing action execution determination unit 102; and a control unit 110, which generates a drive instruction for the feed axis by superimposing the swing instruction on the position instruction of the feed axis. Furthermore, the swing action execution determination unit 102 determines that the swing action is performed intermittently, and the swing instruction generation unit 106 is configured to generate a swing instruction so that the non-swing cutting processing part in the current cutting action includes the swing cutting processing completed part in the previous cutting action, or the swing cutting processing part in the current cutting action includes the non-swing cutting processing completed part in the previous cutting action.

[0051] Thus, by intermittently performing the swinging motion, the chips can be reliably broken without extending the cycle time compared with the past. In addition, the number of swinging motions can be reduced, so the burden on the machine tool caused by the swinging motion can be reduced.

[0052] Furthermore, in the past, due to large position deviations caused by response delays during swinging motions, incomplete cutting would occur and chips would not be crushed. However, according to the present disclosure, since the position deviation converges during non-swinging motions, chips can be effectively crushed when a non-swinging motion of the current path is performed after the swinging motion of the previous path.

[0053] (2) The swing operation execution determination unit 102 is configured to determine execution of the swing operation so that the swing cutting process is performed at a position different from the swing cutting process completed portion in the previous swing cutting process in the current plunge operation.

[0054] As a result, the completed portion of the previous cutting process can be more reliably included in the current cutting process, so that the so-called idle swing can be more reliably generated and the chips can be more reliably broken.

[0055] (3) A swing condition calculation unit 104 is also provided. The swing condition calculation unit 104 calculates the conditions of the swing action output to the swing instruction generation unit 106 based on the machining program, machining parameters and at least one of the feedback values ​​from the above-mentioned machine tool, and the swing condition calculation unit 104 changes the interval of the swing action.

[0056] Thus, the conditions such as the interval, amplitude, and cycle of the swinging motion can be calculated, and the chips can be broken up more reliably. In particular, the length of the chips can be adjusted by changing the interval of the swinging motion.

[0057] (4) The swing condition calculation unit 104 is configured to change the interval of the swing operation between different machining paths. This makes it possible to more reliably break up the chips and adjust the length of the chips.

[0058] (5) The swing condition calculation unit 104 is configured to change the interval of the swing operation within the same machining path. This makes it possible to more reliably break up the chips and adjust the length of the chips.

[0059] (6) The swing condition calculation unit 104 is configured to change the interval of the swing operation according to the diameter of the workpiece 14 .

[0060] Thus, as the number of cutting operations increases, the circumference of the workpiece 14 becomes shorter. As the diameter of the workpiece 14 becomes smaller, the interval of the swinging operation is lengthened, thereby keeping the length of the chips constant, so that the thread cutting process can be performed more efficiently and smoothly.

[0061] (7) The swing operation execution determination unit 102 is configured to determine that, after the cut-in by the swing operation is intermittently performed, the cut-in without the swing operation is performed in the next path.

[0062] Thus, when non-oscillation cutting is performed in the next pass after oscillation cutting, the chips can be reliably broken. For example, the chips can also be reliably broken in the finishing process of the final pass.

[0063] (8) The swing operation execution determination unit 102 is configured to determine that the non-swing cutting process is to be executed until the positional deviation becomes equal to or smaller than a predetermined threshold value in the non-swing cutting process portion based on the intermittent swing operation.

[0064] Thereby, in the non-oscillating cutting portion by the intermittent oscillating motion, the chips can be broken more reliably.

[0065] In addition, the present invention is not limited to the above-described embodiment, and modifications and improvements within the scope that can achieve the object of the present invention are included in the present invention.

[0066] Description of Reference Numerals

[0067] 10: thread groove; 12: screw; 14: workpiece; 16: cutting tool; 18: spindle; 100: control device; 102: swing action execution determination unit; 104: swing condition calculation unit; 106: swing instruction generation unit; 108: adder; 110: control unit; 120: motor; X: X-axis; Z: Z-axis; C: C-axis; L, L1, L2: intervals of the swing action.

Claims

1. A control device for a machine tool, which enables at least one spindle and at least one feed axis to cooperate with each other, and performs thread cutting processing by cutting into a workpiece multiple times in a radial direction by a cutting tool, wherein the at least one spindle causes the cutting tool and the workpiece to rotate relative to each other, and the at least one feed axis causes the cutting tool to move relative to the workpiece, characterized in that: The control device of the above machine tool has: a swing operation execution determination unit for determining whether to execute a swing operation for swinging the cutting tool in a radial direction of the workpiece; a swing instruction generating unit, which generates a swing instruction for the swing action according to the determination result of the swing action execution determining unit; and a control unit that generates a drive command for the feed shaft by superimposing the swing command on a position command for the feed shaft, The swing action execution determination unit determines that the swing action is to be performed intermittently. The above-mentioned swing instruction generating unit generates a swing instruction so that the non-swing cutting processing part in this cutting action includes the swing cutting processing completed part in the previous cutting action, or so that the swing cutting processing part in this cutting action includes the non-swing cutting processing completed part in the previous cutting action.

2. The control device for a machine tool according to claim 1, characterized in that: The swing operation execution determination unit determines the execution of the swing operation so that the swing cutting process is performed at a position different from the swing cutting process completed portion in the previous swing cutting process in the current cutting operation.

3. The control device for a machine tool according to claim 1, characterized in that: The control device of the machine tool further comprises a swing condition calculation unit, which calculates the conditions of the swing operation output to the swing instruction generation unit based on at least one of the machining program, machining parameters and feedback value from the machine tool. The swing condition calculation unit changes an interval of the swing operation.

4. The control device for a machine tool according to claim 2, characterized in that: The control device of the machine tool further comprises a swing condition calculation unit, which calculates the conditions of the swing operation output to the swing instruction generation unit based on at least one of the machining program, machining parameters and feedback value from the machine tool. The swing condition calculation unit changes an interval of the swing operation.

5. The control device for a machine tool according to claim 3, characterized in that: The swing condition calculation unit changes an interval of the swing operation between different machining paths.

6. The control device for a machine tool according to claim 4, characterized in that: The swing condition calculation unit changes an interval of the swing operation between different machining paths.

7. The control device for a machine tool according to any one of claims 3 to 6, characterized in that: The swing condition calculation unit changes an interval of the swing operation within the same machining path.

8. The control device for a machine tool according to any one of claims 3 to 6, characterized in that: The swing condition calculation unit changes an interval of the swing operation according to a diameter of the workpiece.

9. The control device for a machine tool according to claim 7, characterized in that: The swing condition calculation unit changes an interval of the swing operation according to a diameter of the workpiece.

10. The control device for a machine tool according to any one of claims 1 to 6, characterized in that: The oscillation operation execution determination unit determines that the non-oscillation cutting process is to be executed in the non-oscillation cutting process unit based on the intermittent oscillation operation until the position deviation becomes equal to or smaller than a predetermined threshold value.

11. The control device for a machine tool according to claim 7, characterized in that: The oscillation operation execution determination unit determines that the non-oscillation cutting process is to be executed in the non-oscillation cutting process unit based on the intermittent oscillation operation until the position deviation becomes equal to or smaller than a predetermined threshold value.

12. The control device for a machine tool according to claim 8, characterized in that: The oscillation operation execution determination unit determines that the non-oscillation cutting process is to be executed in the non-oscillation cutting process unit based on the intermittent oscillation operation until the position deviation becomes equal to or smaller than a predetermined threshold value.

13. The control device for a machine tool according to claim 9, characterized in that: The oscillation operation execution determination unit determines that the non-oscillation cutting process is to be executed in the non-oscillation cutting process unit based on the intermittent oscillation operation until the position deviation becomes equal to or smaller than a predetermined threshold value.

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