Control method, control device, and machine tool

Abstract

This control method includes: a first step for acquiring a machine control parameter that minimizes the difference between a lower-limit relative movement speed and an actual lower-limit relative movement speed in a plurality of mass states in which a plurality of reference masses are added to a table (20); a second step for generating a first empirical information table (T1) comprising a combination of the plurality of reference masses and corresponding machine control parameters; a third step for acquiring mass information about the table (20) when a machine tool (10) performs oscillation drilling; and a fourth step for acquiring the machine control parameter that corresponds to the mass information from the first empirical information table (T1) and setting the acquired machine control parameter as the machine control parameter for oscillation drilling.

Description

Control method, control device, and machine tool

[0001] The present invention relates to a control method, control device, and machine tool for oscillating hole machining and oscillating turning of a workpiece.

[0002] During drilling, boring, and turning operations, the continuous generation of chips can cause problems such as tool damage, surface damage due to the chips, and clogging of chip removal equipment.

[0003] To solve this problem, a step-feed machining method has been conventionally known, in which the drill is retracted axially during hole drilling to discharge chips from the hole being machined, and then the drill is advanced axially again, and this is repeated to drill a hole to the desired depth. However, in this machining method, the retraction of the drill unit takes time, resulting in a longer machining time. In addition, because the drill tip separates from the workpiece during the retraction of the drill unit, there is a problem that the cutting edge may chip or noise may be generated when the drill tip makes contact with the workpiece again in a way that causes an impact. Furthermore, the increased travel distance due to the retraction motion negatively affects the lifespan of the feed axis device.Therefore, Patent Document 1 discloses an oscillating hole machining method in which a hole is machined in a workpiece by moving a rotating tool such as a drill, boring cutter, or countersink cutter relative to the workpiece, wherein the movement speed of the rotating tool in the direction of its central axis, that is, the relative movement speed between the rotating tool and the workpiece, is changed so as to increase or decrease repeatedly within a range in which the rotating tool does not retract in the direction of its central axis, thereby machining a hole in the workpiece. This allows the wood chips to be broken up.

[0004] However, the behavior of the oscillation changes depending on the mass of the oscillating part. In FIG. 14, an example of the time-series waveform of the cutting feed rate (relative movement speed) is shown with time on the horizontal axis. When the cutting feed rate is varied and oscillated (IW in the figure) so that the minimum cutting feed rate F1 can be reached within the range where the tool and the workpiece do not separate, the portion where the chips are formed thinnest can be made as thin as possible. However, even if the machine tool is operated to achieve such a cutting feed rate, when machining a lighter workpiece compared to the workpiece for which the initial settings of the machine tool were made, if it is operated with the control parameters as set initially (for example, the velocity feed forward coefficient, gain, acceleration / deceleration parameters), the oscillation amplitude becomes smaller (AW in the figure). For this reason, the minimum cutting feed rate F2 that can be reached becomes relatively large, and the portion where the chips are formed thinnest becomes thicker than expected, resulting in a reduction in the chip breaking effect. Also, when machining a heavier workpiece compared to the workpiece for which the initial settings of the machine tool were made, if it is operated with the control parameters as set initially, the oscillation amplitude increases, and the rotating tool retreats in the direction of its central axis, causing the aforementioned problems such as chipping of the tool tip, noise, and adverse effects on the life of the feed axis device.

[0005] Thus, when adjusting the oscillation control of the machine tool according to one mass during the initial setting of the machine tool, if the mass of the oscillating part changes, problems such as a reduction in the chip breaking effect and adverse effects on the tool and the feed axis device occur. Also, in oscillatory machining in which the cutting feed rate of the tool or the workpiece is periodically varied, in order to shorten the machining time, it is necessary to increase the oscillation amplitude or the oscillation frequency of the cutting feed rate. On the other hand, if the speed command value of the cutting feed rate is increased too much when the mass of the oscillating part is large, there is a possibility that the machine tool vibrates and is damaged due to an increase in the inertial force of the oscillating part. Therefore, although it is necessary to set an upper limit value for the oscillation frequency, if the upper limit value of the oscillation frequency is set according to the maximum mass that can be mechanically oscillated, when the oscillating part is lighter than the maximum mass, it is not possible to set a higher oscillation frequency and shorten the machining time.

[0006] Japanese Patent Application Laid-Open No. 2015-052927

[0007] In view of the above circumstances, the present invention aims to provide a control method, a control device, and a machine tool that can improve the chip breaking effect by optimizing the oscillation in accordance with the mass or speed command value of the oscillating part.

[0008] According to one aspect of the present invention, a control method for oscillating hole machining is performed in a machine tool while at least one of the tool and the workpiece is rotating, and the relative position and relative speed of the tool and the workpiece are changed moment by moment within a range in which the tool and the workpiece do not separate from each other, wherein in a state of multiple masses in which multiple reference masses are attached to a tool mounting part for attaching the tool or a workpiece mounting part for attaching the workpiece, the tool mounting part or the workpiece mounting part is oscillated in the same direction as the oscillating hole machining by changing the relative speed between an upper limit relative speed and a lower limit relative speed, and the difference between the lower limit relative speed and the actual lower limit relative speed is such that the tool mounting part and the workpiece mounting part do not separate from each other. A control method is provided, comprising: a first step of acquiring machine control parameters to be minimized within a range for each mass state; a second step of generating a first experimental information table consisting of a combination of a plurality of reference masses and a plurality of machine control parameters acquired for each reference mass; a third step of acquiring at least one mass information of the total mass including the tool in the tool mounting section and the total mass including the workpiece and mounting fixture in the workpiece mounting section when the machine tool receives a command to perform oscillating hole machining; and a fourth step of acquiring machine control parameters corresponding to the mass information from the first experimental information table and setting them as machine control parameters for oscillating hole machining.

[0009] Furthermore, according to one aspect of the present invention, a control method for oscillating hole machining in a machine tool, in which the relative position and relative speed of the tool and workpiece are changed moment by moment within a range in which the tool and workpiece do not separate from each other while at least one of the tool and workpiece is rotated, comprising: a first step of acquiring a reference upper limit oscillation frequency for a plurality of reference speed command values, which is the maximum oscillation frequency within a mechanically operable range when a reference object is placed on a tool mounting part for mounting the tool or a workpiece mounting part for mounting the workpiece and oscillated; and a plurality of reference upper limit oscillation frequencies corresponding to the plurality of reference speed command values A control method is provided which includes: a second step of generating a second experimental information table consisting of a combination of the above; a third step of acquiring a speed command value and a command oscillation frequency for oscillating hole machining when the machine tool receives a command for oscillating hole machining and performs oscillating hole machining; a fourth step of acquiring a reference upper limit oscillation frequency corresponding to the speed command value for oscillating hole machining from the second experimental information table and setting it as the upper limit oscillation frequency in oscillating hole machining; and a fifth step of changing the oscillation frequency in oscillating hole machining to the upper limit oscillation frequency if the command oscillation frequency is greater than the upper limit oscillation frequency.

[0010] Furthermore, according to one aspect of the present invention, a control method for oscillating turning in a machine tool, in which turning is performed by varying the relative movement speed of a tool and a rotating workpiece along the feed direction, wherein in a plurality of mass states in which a plurality of reference masses are attached to a tool mounting part for attaching a tool or a workpiece mounting part for attaching a workpiece, the tool mounting part or the workpiece mounting part is oscillated in the same direction as the oscillating turning based on a speed command value for determining machine control parameters, and the speed difference between the relative movement speed based on the speed command value for determining machine control parameters and the actual relative movement speed is minimized within a range in which the tool mounting part and the workpiece mounting part do not separate from each other. A control method is provided, which includes: a first step of acquiring machine control parameters for each mass state; a second step of generating a first experimental information table consisting of a combination of a plurality of reference masses and a plurality of machine control parameters acquired for each reference mass; a third step of acquiring at least one mass information of the mass of the tool mounting part and the mass of the workpiece mounting part when the machine tool receives a command for oscillating turning and generates an oscillating turning program; and a fourth step of acquiring machine control parameters corresponding to the mass information from the first experimental information table and setting them as machine control parameters in oscillating turning.

[0011] Furthermore, according to one aspect of the present invention, a control method for oscillating turning in a machine tool, in which turning is performed by varying the relative movement speed of a tool and a rotating workpiece along the feed direction, comprising: a first step of acquiring a reference upper limit oscillation frequency for a plurality of reference speed command values, which is the maximum oscillation frequency within a mechanically operable range when a reference object is placed on a tool mounting part for mounting a tool or a workpiece mounting part for mounting a workpiece and oscillated; and a second experimental information table consisting of a plurality of reference speed command values ​​and a plurality of reference upper limit oscillation frequencies corresponding to the plurality of reference speed command values. A control method is provided which includes a second step of generating a bull; a third step of acquiring a speed command value and a commanded oscillation frequency for oscillating turning when the machine tool receives a command for oscillating turning and performs oscillating turning; a fourth step of acquiring a reference upper limit oscillation frequency corresponding to the speed command value for oscillating turning from a second experimental information table and setting it as the upper limit oscillation frequency in oscillating turning; and a fifth step of changing the oscillation frequency in oscillating turning to the upper limit oscillation frequency if the commanded oscillation frequency is greater than the upper limit oscillation frequency.

[0012] According to a control method in one aspect of the present invention, in multiple mass states in which multiple reference masses are added to the tool mounting part or workpiece mounting part, it is possible to obtain a machine control parameter for each mass state that minimizes the difference between the lower limit relative movement speed and the actual lower limit relative movement speed within a range in which the tool mounting part and the workpiece mounting part do not separate from each other. For this reason, a first experimental information table consisting of a combination of multiple reference masses and multiple corresponding machine control parameters can be generated. Furthermore, a machine control parameter corresponding to at least one mass information of the mass of the tool mounting part and the mass of the workpiece mounting part in oscillating hole machining can be obtained from the first experimental information table and set as a machine control parameter in oscillating hole machining. This makes it possible to optimize the oscillation in accordance with the mass of the oscillating part and improve the chip breaking effect in oscillating hole machining, in which the relative position and relative movement speed of the tool and workpiece are changed moment by moment within a range in which they do not separate from each other.

[0013] Furthermore, according to a control method in one aspect of the present invention, when a reference object is placed on the tool mounting section or workpiece mounting section and oscillated, a reference upper limit oscillation frequency, which is the maximum oscillation frequency within the mechanically operable range, can be obtained for multiple reference speed command values. Therefore, a second experimental information table consisting of a combination of multiple reference speed command values ​​and the corresponding multiple reference upper limit oscillation frequencies can be generated. In addition, when performing oscillating hole machining in response to an oscillating hole machining command, the reference upper limit oscillation frequency corresponding to the speed command value obtained can be obtained from the second experimental information table and set as the upper limit oscillation frequency in oscillating hole machining. Also, if the calculated oscillation frequency is greater than the upper limit oscillation frequency, the oscillation frequency in oscillating hole machining can be changed to the upper limit oscillation frequency. As a result, in oscillating hole machining, where the relative position and relative movement speed of the tool and workpiece are changed moment by moment within a range that does not separate them, oscillating hole machining can be performed without vibration in accordance with the speed command value.

[0014] Furthermore, according to a control method in one aspect of the present invention, in multiple mass states in which multiple reference masses are added to the tool mounting part or workpiece mounting part, it is possible to acquire machine control parameters for each mass state that minimize the speed difference between the relative moving speed based on the speed command value for determining machine control parameters and the actual relative moving speed, within a range in which the tool mounting part or workpiece mounting part does not separate. For this reason, a first experimental information table can be generated consisting of a combination of multiple reference masses and multiple machine control parameters acquired for each reference mass. Furthermore, machine control parameters corresponding to at least one mass information of the mass of the tool mounting part and the mass of the workpiece mounting part in oscillating turning can be acquired from the first experimental information table and set as machine control parameters in oscillating turning. This makes it possible to optimize the oscillation in accordance with the mass of the oscillating part and improve the chip breaking effect in oscillating turning, in which turning is performed by varying the relative moving speed of the tool and the rotating workpiece along the feed direction.

[0015] Furthermore, according to a control method in one aspect of the present invention, when a reference object is placed on the tool mounting section or workpiece mounting section and oscillated, a reference upper limit oscillation frequency, which is the maximum oscillation frequency within the mechanically operable range, can be obtained for multiple reference speed command values. Therefore, a second experimental information table consisting of a combination of multiple reference speed command values ​​and the corresponding multiple reference upper limit oscillation frequencies can be generated. In addition, when oscillating turning is performed in response to an oscillating turning command, the reference upper limit oscillation frequency corresponding to the speed command value obtained can be obtained from the second experimental information table and set as the upper limit oscillation frequency in oscillating turning. Also, if the command oscillation frequency is greater than the upper limit oscillation frequency, the oscillation frequency in oscillating turning can be changed to the upper limit oscillation frequency. As a result, in oscillating turning, in which turning is performed by varying the relative movement speed of the tool and the rotating workpiece along the feed direction, oscillating turning can be performed without vibration in accordance with the speed command value.

[0016] Figure 1 shows a side view of a machine tool for oscillating hole machining according to this embodiment. Figure 2 shows a side view of the machine tool when the table oscillates on its own. Figure 3 shows a side view of the machine tool when it oscillates in multiple mass states. Figure 4 shows a flowchart for generating the first experimental information table. Figure 5 shows an example of the first experimental information table. Figure 6 shows a flowchart for performing oscillating hole machining using the first experimental information table. Figure 7 shows a flowchart for generating the second experimental information table. Figure 8 shows an example of the second experimental information table. Figure 9 shows a flowchart for performing oscillating hole machining using the second experimental information table. Figure 10 shows a flowchart for generating the third experimental information table. Figure 11 shows an example of the third experimental information table. Figure 12 shows a flowchart for performing oscillating hole machining using the third experimental information table. Figure 13 shows a side view of a machine tool for oscillating turning according to this embodiment. Figure 14 shows an example of a time series of cutting feed rates in conventional oscillating machining.

[0017] The control method, control device, and machine tool according to the embodiment will be described below with reference to the attached drawings. Similar or corresponding elements are denoted by the same reference numerals, and redundant explanations will be omitted. The scale of the drawings may be changed in some cases to facilitate understanding.

[0018] (First Embodiment) The control method according to the first embodiment will be described with reference to Figures 1 to 6. Figure 1 shows a side view of the machine tool 10 according to this embodiment. The machine tool 10 comprises a bed 12 which serves as a base and a column 14 erected on the upper surface of the bed 12. The machine tool 10 has a predetermined machine coordinate system with a predetermined position as the origin, and includes the X-axis (direction perpendicular to the plane of the paper), the Y-axis (vertical direction of the plane of the paper), and the Z-axis (left-right direction of the plane of the paper) as mutually orthogonal linear axes. The machine tool 10 according to this embodiment is horizontal, and the Z-axis extends along the horizontal direction. The X-axis and Y-axis are set on a plane perpendicular to the Z-axis, in this case, on a vertical plane.

[0019] A spindle 16, which serves as a tool mounting section, is mounted on the front of the column 14 and is configured to rotate around an axis parallel to the Z-axis direction. Furthermore, a tool 18 for machining the workpiece W while rotating together with the spindle 16 is detachably attached to the spindle 16. The spindle 16 is also configured to move along the X-axis and Y-axis directions.

[0020] A table 20, which serves as a workpiece mounting section, is positioned on the upper surface of the bed 12 for mounting the workpiece W, which is the object to be processed, using a mounting jig 22. The table 20 is configured to be movable in the Z-axis direction on the bed 12 via a guide surface. The bed 12 also has a mass information detection unit 24 for detecting the mass of objects placed on the table 20, such as the workpiece W.

[0021] The machine tool 10 is equipped with a feed device (not shown) having a feed axis for moving the spindle 16 and the workpiece W along the X-axis, Y-axis, and Z-axis directions. As a result, the machine tool 10 is configured to allow the table 20 on which the spindle 16 and the workpiece W are placed to move relative to each other along the X-axis, Y-axis, and Z-axis.

[0022] As shown in Figure 2, the machine tool 10 is equipped with a control device 26 that operates the feed device and moves the spindle 16 and the table 20 on which the workpiece W is placed relatively (RM in the figure) by executing a stored NC program. The control device 26 is configured to control oscillating hole machining, in which, with at least one of the tool 18 and the workpiece W rotating in the machine tool 10, the tool 18 and / or the workpiece W are moved RM relative to each other based on a speed command value, and the relative position and relative movement speed are changed moment by moment within a range in which they do not separate from each other to machine a hole. Here, "do not separate" means that in the direction of relative movement RM in which the tool 18 and the workpiece W approach each other during oscillating hole machining, the tool 18 and the workpiece W do not separate in the Z-axis direction in terms of the linear axis of the machine tool. Furthermore, in this specification, "speed command value" refers to a value commanded on the NC program to determine the relative movement speed (cutting feed rate), such as "F500," or a value stored in each memory unit. "Relative movement speed" refers to the cutting feed rate in the machining direction of the oscillating part, which changes moment by moment when an oscillating hole machining command including a speed command value is issued. When an oscillating hole machining command including a speed command value is issued, an oscillating hole machining program is generated to oscillate by changing the relative movement speed between an upper limit relative movement speed and a lower limit relative movement speed. The lower limit relative movement speed is F=0 or a positive value, and may be stored in the memory unit in advance, or it may be commanded each time with the oscillating hole machining command. The oscillating hole machining program may be generated so that the upper limit relative movement speed is twice the speed command value. For example, when the speed command value is commanded as F500, the oscillating hole machining program is generated so that the relative movement speed (cutting feed rate) oscillates between F0 and F1000. Alternatively, the oscillating hole machining program may be generated so that the speed command value is the same as the upper limit relative movement speed.

[0023] Furthermore, the control device 26 is electrically connected to the mass information detection unit 24 and is configured to acquire and store (save) mass information such as the mass of the placed object, such as the workpiece W, detected by the mass information detection unit 24.

[0024] The machine tool 10 is configured to generate a first experimental information table T1 (see Figure 5) for optimizing the control of the feed axis device for relative movement RM of the tool 18 and / or workpiece W prior to oscillating hole machining. Specifically, the machine tool 10 generates a first experimental information table T1 in which machine control parameters for controlling the feed axis device, in this case a servo motor (not shown) for driving the feed axis device are set. The machine control parameter referred to here is the velocity feedforward coefficient used to determine the acceleration command value commanded to the servo motor in order to reduce the deviation (velocity error) of the relative movement speed. The velocity feedforward coefficient, in this context, is a coefficient that indicates whether to add a predictable movement delay to the command in advance when operating the spindle 16 or workpiece W. In the following explanation, the machine control parameter is described as the velocity feedforward coefficient, but it is not limited to this, and other machine control parameters may be used, for example, a position feedforward coefficient in combination with the velocity feedforward coefficient, or gains (velocity loop gain, position loop gain) or acceleration / deceleration parameters may be used. Gain is the ratio of output to input, and in the case of a servo motor, it is a mechanical control parameter used to optimize its responsiveness and operational stability. Generally, increasing the gain improves the responsiveness and operational stability of the servo motor, but if the gain is too high, it can cause vibrations depending on the weight of the spindle 16 or the workpiece W. The acceleration / deceleration parameter is a mechanical control parameter used to suppress the shocks of acceleration and deceleration that occur when the machine starts moving or stops. The larger the mass of the spindle 16 or the workpiece W, the more preferable it is to increase the acceleration / deceleration parameter and set a longer acceleration / deceleration time.

[0025] The machine control parameters are set for each mass state of the table 20, that is, for each mass of the workpiece W placed on the table 20. First, as shown in Figure 2, the table 20 alone (no object placed in Figure 5) and the tool 18 are moved relative RM at an upper relative movement speed determined from a rocking hole machining command that includes a predetermined speed command value for determining the machine control parameters, and a predetermined lower relative movement speed. The speed feedforward coefficient is set so that the difference between the smallest relative movement speed among the actual cutting feed speeds (relative movement speeds) when the table 20 alone is rocked, that is, the lower relative movement speed of the actual rocking waveform, and the predetermined lower relative movement speed is minimized. Here, the predetermined lower relative movement speed is stored in the memory of the control device 26, but it may also be commanded individually in the rocking hole machining command. Note that by minimizing the difference in the lower relative movement speed, the difference in the upper relative movement speed, which shares the speed feedforward coefficient, is also minimized.

[0026] Next, as shown in Figure 3, reference mounts SW1, SW2, and SW3 (the first, second, and third reference mounts in Figure 5), each with different reference masses M2, M3, and M4 (see Figure 5), which have been prepared in advance in the stocker SK, are placed on the table 20. Note that reference mass M1 refers to the mass of the table 20 alone with nothing placed on it. With one of the multiple reference mounts SW1, SW2, and SW3 placed on the table 20, the tool 18 and the table 20 are moved relative to each other using RM, and the speed feedforward coefficient is set so that when the workpiece SW1, SW2, and SW3 are oscillated, they match a predetermined lower limit relative movement speed. Note that here, three reference mounts SW1, SW2, and SW3 are used, but this is not limited to three; two or four or more may be used.

[0027] The first experimental information table T1 is generated more specifically according to the flowchart shown in Figure 4. In step S10, when the generation of the first experimental information table T1 is started, the process moves to step S20, where a table 20 in one mass state, i.e., either the table 20 alone or the table 20 with the reference objects SW1, SW2, SW3 placed on it, is moved relative to the speed command value used for determining the machine control parameters, i.e., oscillated. When the table 20 is oscillated, the process moves to step S30, and if the lower limit relative movement speed when oscillating is not the predetermined lower limit relative movement speed, the process moves to step S40, where the speed feedforward coefficient, which is used as the reference machine control parameter, is adjusted to the minimum possible range so that the spindle 16 and the table 20 do not separate from each other. Here, "lower limit relative movement speed when oscillating" means the smallest relative movement speed among the relative movement speeds when the machine is actually oscillating, which can be determined by checking the servo waveform of the feed axis motor of the table 20 with servo adjustment software when the table 20 is oscillated. In the adjustment process, if the lower limit relative movement speed during oscillation is greater than a predetermined lower limit relative movement speed, in other words, if the amplitude of the sine wave traced by the actual relative movement speed during oscillation is smaller than the amplitude of the sine wave specified by the speed command value for determining the machine control parameters, the speed feedforward coefficient is increased. If the lower limit relative movement speed during oscillation is less than a predetermined lower limit relative movement speed, in other words, if the actual relative movement speed during oscillation is greater than the amplitude of the sine wave specified by the speed command value for determining the machine control parameters, the speed feedforward coefficient is decreased. As a result of the adjustment, if the lower limit relative movement speed during oscillation becomes the predetermined lower limit relative movement speed within the range where the main shaft 16 and the table 20 do not separate, the process proceeds to step S50, and the speed feedforward coefficient is recorded (stored) in the first experimental information table T1 stored in the control device 26 as a reference machine control parameter, in relation to the mass state. In step S40, if the difference between the lower limit relative movement speed when oscillating and the predetermined lower limit relative movement speed becomes the minimum adjustable value according to the specifications of the adjustment device or feed axis device, it may be considered that the speed has been adjusted to the command value, and the process may proceed to step S50.

[0028] Once the velocity feedforward coefficient for one mass state is recorded, the process proceeds to step S60. If the velocity feedforward coefficients for other mass states have not yet been set, the process proceeds to step S70 to change the mass state and repeats the process of setting the velocity feedforward coefficients for the remaining mass states. Once the settings for all mass states are complete, the process proceeds to step S80 to generate the first experimental information table T1 as shown in Figure 5, and then proceeds to step S90 to complete the generation.

[0029] The machine tool 10 can perform oscillating hole machining using the generated first experimental information table T1. Figure 6 shows a flowchart of oscillating hole machining using the first experimental information table T1. First, the process moves to step S110, where the user commands oscillating hole machining and inputs the spindle rotation speed, speed command value, number of teeth, and hole depth. The oscillating hole machining command refers to inputting "G**Z**S**F**T**" in the block that commands oscillating hole machining within the NC program. Here, G is the G code for commanding oscillating hole machining, Z is the hole machining depth, S is the spindle rotation speed, F is the cutting feed rate (speed command value), and T represents the number of teeth of the tool 18 used for oscillating hole machining. As mentioned above, the lower limit relative movement speed may also be commanded. When the machine tool 10 receives the oscillating hole machining command, it moves to step S120 and generates an oscillating hole machining program based on the user's input. When the machine tool 10 generates a swivel hole machining program, it proceeds to step S130 to check whether the total mass of the table 20, the mounting jig 22, and the workpiece W on the table 20 is recorded in the control device 26. If it is not recorded, it proceeds to step S140 to send a mass detection command to the mass information detection unit 24.

[0030] When the mass information detection unit 24 receives a mass detection command, the process moves to step S150, where the control device 26 operates the table 20 based on a pre-stored speed command value for mass information detection. The inertia of the table 20 is detected by the mass information detection unit 24, and the total mass of the table 20, the mounting jig 22, and the workpiece W on the table 20 is estimated. Once the mass is estimated, the process moves to step S160, where the control device 26 records the mass information, which is the total mass detected by the mass information detection unit 24.

[0031] When the control device 26 records the mass information, it proceeds to step S170 and obtains the machine control parameters corresponding to the mass information from the first experimental information table T1. Specifically, it interpolates or extrapolates the relationship between the mass information and the reference machine control parameters recorded in the first experimental information table T1 to calculate the machine control parameters corresponding to the detected mass information. The control device 26 sets the calculated machine control parameters as the machine control parameters for the rocking hole machining to be performed.

[0032] Once the machine control parameters are set, the process moves to step S180, where the oscillation frequency Fb = fd × t / 2 is calculated from the spindle rotation speed fd and the number of teeth t, and the process moves to step S190 to start the oscillating hole machining.

[0033] In this oscillating hole machining program, the number of blocks per cycle of the cutting feed rate (relative movement speed) is determined based on a predetermined reference time and a determined oscillation frequency. The reference time refers to the response speed of the control device 26 and represents the speed at which one line (one block) of the NC program can be read. For example, if the determined basic oscillation frequency is 25 Hz, one cycle of the sine curve of the oscillation speed in oscillating hole machining will be 40 msec. If, for example, the reference time is predetermined to be 5 msec, the number of blocks per cycle will be 8. Alternatively, the number of blocks per cycle can be predetermined, and the reference time can be determined according to the basic oscillation frequency. The reason for setting the reference time in this way is that if the number of blocks per cycle is a multiple of 4, the blocks can be placed exactly at the peaks of the sine wave, that is, at the peaks corresponding to the upper limit relative movement speed or the lower limit relative movement speed, thereby precisely representing the sine wave of the set oscillation speed. In the oscillating hole machining program, position commands and speed commands are issued for each block per cycle set in this manner. Specifically, a point cloud program for oscillating hole machining is generated in the format of "~Z-1.0F250; (end of block) Z-1.5F300; ~". In this way, a point cloud program for oscillating hole machining is generated that includes speed command values ​​and position command values ​​so that the relative movement speed oscillates in a sine wave pattern over time, as the relative position of the workpiece W and the tool 18 changes moment by moment. This program allows the machine tool 10 to be operated to perform oscillating hole machining.

[0034] Next, the operation and effects of the control method, control device 26, and machine tool 10 according to this embodiment will be described below.

[0035] According to the control method, control device 26, and machine tool 10 of this embodiment, in multiple mass states in which multiple reference masses M1, M2, M3, and M4 are attached to the spindle 16 or table 20, the spindle 16 or table 20 is oscillated by changing the relative movement speed so as to draw an oscillating waveform between an upper limit relative movement speed and a lower limit relative movement speed in the same direction as the oscillating hole machining. For each mass state, machine control parameters can be obtained that minimize the difference between the lower limit relative movement speed and the lower limit relative movement speed of the actual oscillating waveform within a range in which the spindle 16 and table 20 do not separate from each other. For this reason, a first experimental information table T1 can be generated, consisting of a combination of multiple reference masses M1, M2, M3, and M4 and multiple reference machine control parameters obtained for each reference mass M1, M2, M3, and M4. Furthermore, machine control parameters corresponding to at least one mass information of the mass of the spindle 16 and the mass of the table 20 in oscillating hole machining can be obtained from the first experimental information table T1 and set as machine control parameters for oscillating hole machining. This makes it possible to optimize the oscillation in accordance with the mass of the oscillating part and improve the chip breaking effect in oscillating hole machining, where the relative position and relative movement speed of the tool 18 and the workpiece W are changed moment by moment within a range that does not cause them to separate.

[0036] Furthermore, according to the control device 26 and machine tool 10 of this embodiment, in the oscillating hole machining program, by making the number of blocks per cycle of the oscillating cutting feed rate (relative movement speed) a multiple of 4, the sine wave of the set oscillating speed can be precisely represented. This makes it possible to optimize the oscillating motion in accordance with the mass of the oscillating part and improve the chip breaking effect in oscillating hole machining, where the relative position and relative movement speed of the tool 18 and the workpiece W are changed moment by moment within a range where they do not separate from each other.

[0037] As described above, the control method, control device 26, and machine tool 10 according to this embodiment can optimize the oscillation in accordance with the mass of the oscillating workpiece W and table 20, thereby improving the chip breaking effect in oscillating hole machining.

[0038] (Second Embodiment) The control method, control device 26, and machine tool 10 according to the second embodiment will be described below with reference to Figures 7 to 9. Elements that are the same as or corresponding to the first embodiment are denoted by the same reference numerals, and redundant explanations are omitted.

[0039] The machine tool 10 is configured to generate a second experimental information table T2 (see Figure 8) for optimizing the control of the feed axis device for relative movement RM of the tool 18 and / or workpiece W prior to oscillating hole machining. Specifically, the machine tool 10 generates a second experimental information table T2 that sets a reference upper limit oscillation frequency (Fr1 to Fr4 in Figure 8), which is the maximum oscillation frequency of the servo motor for driving the feed axis device within the mechanically operable range, for a plurality of reference speed command values ​​(FS1 to FS4 in Figure 8).

[0040] The second experimental information table T2 is generated according to the flowchart shown in Figure 7. In step S210, when the generation of the second experimental information table T2 is started, the process moves to step S220, where the table 20 on which the reference object is placed is moved relative to the table based on a reference speed command value and an initial oscillation frequency, i.e., oscillated. Here, the initial oscillation frequency is set to a small value that does not cause vibration, and the experiment is started. When the table 20 is oscillated, the process moves to step S230, and while the table 20 does not vibrate, the process moves to step S240, where the oscillation frequency is gradually increased from the initial oscillation frequency. When the oscillation frequency reaches its maximum while the table 20 does not vibrate, the process moves to step S250, where this upper limit oscillation frequency (reference upper limit oscillation frequency) is associated with the reference speed command value and recorded (stored) in the second experimental information table T2 stored in the control device 26.

[0041] Once the reference upper limit fluctuation frequency for one reference speed command value is recorded, the process proceeds to step S260. If the setting of the reference upper limit fluctuation frequencies for other reference speed command values ​​is incomplete, the process proceeds to step S270, and the setting of the reference upper limit fluctuation frequencies for the remaining reference speed command values ​​is repeated. Once the setting of the reference upper limit fluctuation frequencies for all reference speed command values ​​is complete, the process proceeds to step S280, where the second experimental information table T2 is generated as shown in Figure 8, and the generation is completed in step S290.

[0042] The machine tool 10 can perform oscillatory hole machining using the generated second experimental information table T2. FIG. 9 shows a flowchart of oscillatory hole machining using the second experimental information table T2. First, it proceeds to step S310, and the user inputs the spindle rotation speed, speed command value, number of cutting edges, and hole depth as an oscillatory hole machining command. When the machine tool 10 receives the oscillatory hole machining command, it proceeds to step S320 and generates an oscillatory hole machining program based on the input from the user. When the machine tool 10 generates the oscillatory hole machining program, it proceeds to step S330.

[0043] When it proceeds to step S330, the control device 26 acquires the upper limit oscillation frequency corresponding to the speed command value input at the time of the oscillatory hole machining command from the second experimental information table T2. Specifically, the relationship between the reference speed command value and the reference upper limit oscillation frequency recorded in the second experimental information table T2 is interpolated or extrapolated to calculate the upper limit oscillation frequency corresponding to the speed command value input at the time of the oscillatory hole machining command. After calculating the upper limit oscillation frequency, it proceeds to step S340, calculates the oscillation frequency Fb = fd × t / 2 as the commanded oscillation frequency from the spindle rotation speed fd and the number of cutting edges t, and proceeds to step S350.

[0044] The control device 26 compares the calculated oscillation frequency with the upper limit oscillation frequency. If the calculated oscillation frequency is greater than the upper limit oscillation frequency, it proceeds to step S370 and sets the oscillation frequency in the oscillatory hole machining to the upper limit oscillation frequency. If the calculated oscillation frequency is the same as or smaller than the upper limit oscillation frequency, it proceeds to step S360 and sets the calculated oscillation frequency as the oscillation frequency in the oscillatory hole machining. When these confirmations and settings are completed, it proceeds to step S380 and performs oscillatory hole machining.

[0045] According to the control method, control device 26, and machine tool 10 of this embodiment, when a reference object is placed on the table 20 and oscillated, a reference upper limit oscillation frequency, which is the maximum oscillation frequency within the mechanically operable range, can be obtained for multiple reference speed command values. Therefore, a second experimental information table T2 can be generated, consisting of a combination of multiple reference speed command values ​​and the corresponding multiple reference upper limit oscillation frequencies. Furthermore, when a command for oscillating hole machining is received and an oscillating hole machining program is generated, the reference upper limit oscillation frequency corresponding to the speed command value obtained can be obtained from the second experimental information table T2 and set as the upper limit oscillation frequency in oscillating hole machining. Also, if the calculated oscillation frequency is greater than the upper limit oscillation frequency, the oscillation frequency in oscillating hole machining can be set to the upper limit oscillation frequency. As a result, in oscillating hole machining, in which the relative position and relative movement speed of the tool 18 and the workpiece W are changed moment by moment within a range where they do not separate from each other, oscillating hole machining can be performed without vibration in accordance with the speed command value.

[0046] (Third Embodiment) Hereinafter, the control method, control device 26, and machine tool 10 according to the third embodiment will be described with reference to Figures 10 to 12. Elements that are the same as or corresponding to those in the first and second embodiments are denoted by the same reference numerals, and redundant explanations are omitted.

[0047] The machine tool 10 is configured to generate a third experimental information table T3 (see Figure 11) for optimizing the control of the feed axis device for relative movement RM of the tool 18 and / or workpiece W prior to oscillating hole machining. Specifically, the machine tool 10 generates a third experimental information table T3 that sets a reference upper limit oscillation frequency (Fr1 to Fr8 in Figure 11, including subsequent data not shown) which is the maximum oscillation frequency of the servo motor for driving the feed axis device within the mechanically operable range, for multiple mass states (M1 and M2 in Figure 11, including subsequent data not shown) and multiple reference speed command values ​​(FS1 to FS8 in Figure 11, including subsequent data not shown).

[0048] The third experimental information table T3 is generated according to the flowchart shown in FIG. 10. When the generation of the third experimental information table T3 starts in step S410, the process proceeds to step S420, and a table 20 with one reference load placed thereon is relatively moved, that is, oscillated, based on one reference speed command value and an initial oscillation frequency. Here, the experiment is started by setting the initial oscillation frequency to a small value at which no vibration occurs. When the table 20 is oscillated, the process proceeds to step S430, and when it is within the range where the table 20 does not vibrate, the process proceeds to step S440, and the oscillation frequency is gradually increased. When the oscillation frequency reaches the maximum within the range where the table 20 does not vibrate, the process proceeds to step S450, and this upper limit oscillation frequency (reference upper limit oscillation frequency) is recorded (stored) in the third experimental information table T3 stored in the control device 26 in association with the mass state and the reference speed command value.

[0049] When the reference upper limit oscillation frequency at one reference speed command value is recorded, the process proceeds to step S460. Here, if the setting of the reference upper limit oscillation frequency at other reference speed command values is incomplete, the process proceeds to step S470, and the setting of the reference upper limit oscillation frequency at the remaining reference speed command values is repeated. When the setting of the reference upper limit oscillation frequency for all reference speed command values is completed, the process proceeds to step S480. If the setting of the reference upper limit oscillation frequency in other mass states is incomplete, the process proceeds to step S490, and the reference load placed on the table 20 is changed to change the mass state. When the mass state is changed, the process proceeds to step S420, and the setting of the reference upper limit oscillation frequency in that mass state is repeated. When the setting of the reference upper limit oscillation frequency for all mass states is completed, the process proceeds to step S500, and as shown in FIG. 11, the third experimental information table T3 is generated, and the generation is terminated in step S510.

[0050] The machine tool 10 can perform oscillating hole machining using the generated third experimental information table T3. Figure 12 shows a flowchart of oscillating hole machining using the third experimental information table T3. First, the process moves to step S610, where the user commands oscillating hole machining and inputs the spindle rotation speed, speed command value, number of teeth, and hole depth. Upon receiving the oscillating hole machining command, the machine tool 10 moves to step S620 and generates an oscillating hole machining program based on the user's input. Once the machine tool 10 has generated the oscillating hole machining program, it moves to step S630.

[0051] The process moves to step S630, where the control device 26 checks whether the total mass of the table 20, the mounting jig 22, and the workpiece W on the table 20 has been recorded. If it has not been recorded, the process moves to step S640, where a mass detection command is sent to the mass information detection unit 24.

[0052] When the mass information detection unit 24 receives a mass detection command, the process moves to step S650, where the control device 26 operates the table 20 based on a pre-stored speed command value for mass information detection. The inertia of the table 20 is detected by the mass information detection unit 24, and the total mass of the table 20, the mounting jig 22, and the workpiece W on the table 20 is estimated. Once the total mass is estimated, the process moves to step S660, where the control device 26 records the mass information, which is the total mass detected by the mass information detection unit 24.

[0053] When the control device 26 records the mass information, it proceeds to step S670 and obtains the upper limit oscillation frequency corresponding to the mass information and speed command value from the third experimental information table T3. Specifically, it first compares the relationship between the recorded mass information and the multiple reference masses recorded in the third experimental information table T3, and obtains a reference mass that is larger than the mass information and is the closest value. Next, it interpolates or extrapolates the relationship between the multiple reference speed command values ​​corresponding to the obtained reference mass recorded in the third experimental information table T3 and the reference upper limit oscillation frequency to calculate the upper limit oscillation frequency corresponding to the speed command value input when the oscillation hole machining command is issued. Once the upper limit oscillation frequency is calculated, it proceeds to step S680, calculates the oscillation frequency Fb = fd × t / 2 as the command oscillation frequency from the spindle rotation speed fd and the number of teeth t, and proceeds to step S690.

[0054] The control device 26 compares the calculated oscillation frequency with the upper limit oscillation frequency. If the calculated oscillation frequency is greater than the upper limit oscillation frequency, it proceeds to step S710 and sets the oscillation frequency for the oscillating hole machining to the upper limit oscillation frequency. If the calculated oscillation frequency is the same as or less than the upper limit oscillation frequency, it proceeds to step S700 and sets the calculated oscillation frequency to the oscillation frequency for the oscillating hole machining. Once these confirmations and settings are complete, it proceeds to step S720 and performs the oscillating hole machining.

[0055] According to the control method, control device 26, and machine tool 10 of this embodiment, when a reference object is placed on the table 20 and oscillated, a reference upper limit oscillation frequency, which is the maximum oscillation frequency within the mechanically operable range, can be obtained for multiple mass states and reference speed command values. Therefore, a third experimental information table T3 can be generated, consisting of a combination of multiple mass states and reference speed command values ​​and the corresponding multiple reference upper limit oscillation frequencies. Furthermore, when generating an oscillating hole machining program in response to an oscillating hole machining command, the reference upper limit oscillation frequency corresponding to the speed command value and mass state obtained can be acquired from the third experimental information table T3 and set as the upper limit oscillation frequency in oscillating hole machining. In addition, if the oscillation frequency calculated based on the oscillating hole machining command is greater than the upper limit oscillation frequency, the oscillation frequency in oscillating hole machining can be changed to the upper limit oscillation frequency. This makes it possible to perform oscillating hole machining without vibration in accordance with the mass and speed command values ​​of the oscillating part, in oscillating hole machining where the relative position and relative movement speed of the tool 18 and the workpiece W are changed moment by moment within a range where they do not separate from each other.

[0056] (Fourth Embodiment) Hereinafter, the control method, control device 26, and machine tool 30 according to the fourth embodiment will be described with reference to Figure 13. Elements that are the same as or corresponding to the first to third embodiments are denoted by the same reference numerals, and redundant explanations are omitted.

[0057] Figure 13 shows a side view of the machine tool 30 according to this embodiment. The machine tool 30 is configured as a turning machine tool for turning by moving a cutting tool 40, which is a tool, and a rotating workpiece W relative to each other. For this reason, the machine tool 30 is positioned above the bed 12 and includes a workpiece spindle 42 as a workpiece mounting part that rotates the workpiece W, which is mounted via a chuck 44. The machine tool 30 also includes a feed device (not shown) for moving the cutting tool 40 and the workpiece spindle 42 relative to each other.

[0058] According to the control method, control device 26, and machine tool 30 of this embodiment, in multiple mass states in which multiple reference masses M1, M2, M3, and M4 are attached to the spindle 16 or work spindle 42, the spindle 16 or work spindle 42 is oscillated by changing the relative movement speed so as to draw an oscillating waveform between an upper limit relative movement speed and a lower limit relative movement speed in the same direction as oscillating turning, and machine control parameters that minimize the difference between the lower limit relative movement speed and the lower limit relative movement speed of the actual oscillating waveform can be obtained for each mass state. For this reason, a first experimental information table T1 can be generated, consisting of a combination of multiple reference masses M1, M2, M3, and M4 and multiple machine control parameters obtained for each reference mass M1, M2, M3, and M4. Furthermore, machine control parameters corresponding to at least one mass information of the mass of the spindle 16 and the mass of the work spindle 42 in oscillating turning can be obtained from the first experimental information table T1 and set as machine control parameters in oscillating turning. This makes it possible to optimize the oscillation in accordance with the mass of the oscillating part and improve the chip breaking effect in oscillating turning, where the relative position and relative movement speed of the cutting tool 40 and the workpiece W are changed moment by moment within a range that does not cause them to separate.

[0059] According to the control method, control device 26, and machine tool 30 of this embodiment, when a reference object is placed on the workpiece spindle 42 and oscillated, a reference upper limit oscillation frequency, which is the maximum oscillation frequency within the mechanically operable range, can be obtained for multiple reference speed command values. Therefore, a second experimental information table T2 can be generated, consisting of a combination of multiple reference speed command values ​​and the corresponding multiple reference upper limit oscillation frequencies. Furthermore, when generating an oscillating turning program in response to an oscillating turning command, the reference upper limit oscillation frequency corresponding to the speed command value obtained can be acquired from the second experimental information table T2 and set as the upper limit oscillation frequency in oscillating turning. Also, if the calculated oscillation frequency is greater than the upper limit oscillation frequency, the oscillation frequency in oscillating turning can be changed to the upper limit oscillation frequency. As a result, in oscillating turning, in which the relative position and relative moving speed of the cutting tool 40 and the workpiece W are changed moment by moment within a range where they do not separate from each other, oscillating turning can be performed without vibration in accordance with the speed command value.

[0060] According to the control method, control device 26, and machine tool 30 of this embodiment, when a reference object is placed on the workpiece spindle 42 and oscillated, a reference upper limit oscillation frequency, which is the maximum oscillation frequency within the mechanically operable range, can be obtained for multiple mass states and reference speed command values. Therefore, a third experimental information table T3 can be generated, consisting of a combination of multiple mass states and reference speed command values ​​and the corresponding multiple reference upper limit oscillation frequencies. Furthermore, when generating an oscillating turning program in response to an oscillating turning command, the reference upper limit oscillation frequency corresponding to the speed command value and mass state obtained can be acquired from the third experimental information table T3 and set as the upper limit oscillation frequency in oscillating turning. In addition, if the oscillation frequency calculated based on the oscillating hole machining command is greater than the upper limit oscillation frequency, the oscillation frequency in oscillating turning can be changed to the upper limit oscillation frequency. This enables oscillating hole machining in oscillating turning operations, where the relative position and relative movement speed of the cutting tool 40 and the workpiece W are changed moment by moment within a range that does not cause them to separate, in accordance with the mass and speed command value of the oscillating part, without vibration.

[0061] As described above, the control method, control device 26, and machine tool 10 according to this embodiment can optimize the oscillation in accordance with the mass of the oscillating workpiece W and workpiece spindle 42, thereby improving the chip breaking effect in oscillating turning.

[0062] The embodiments of the control method, control device 26, and machine tools 10 and 30 for oscillating hole machining and oscillating turning of workpiece W have been described above, but the present invention is not limited to the embodiments described above. In addition to the above, it is expected that those skilled in the art will understand that various modifications of the above embodiments are possible. For example, as mentioned above, when a gain is used instead of a velocity feedforward coefficient as a machine control parameter, a first experimental information table can be generated in which the gain becomes smaller as the mass of the oscillating part increases. Also, when an acceleration / deceleration parameter is used instead of a velocity feedforward coefficient as a machine control parameter, a first experimental information table can be generated in which the acceleration / deceleration parameter becomes larger as the mass of the oscillating part increases.

[0063] 10 Machine tool 16 Spindle (tool mounting section) 18 Tool 20 Table (workpiece mounting section) 24 Mass information detection unit 26 Control device 30 Machine tool 40 Cutting tool (tool) 42 Workpiece spindle (workpiece mounting section) M1 Reference mass M2 Reference mass M3 Reference mass SW1 Reference object SW2 Reference object SW3 Reference object T1 First experimental information table T2 Second experimental information table T3 Third experimental information table W Workpiece

Claims

1. A control method for oscillating hole machining in a machine tool, in which the relative position and relative movement speed of the tool and the workpiece are changed moment by moment within a range in which the tool and the workpiece do not separate from each other, while the tool and the workpiece are rotating, comprising: a first step of acquiring a machine control parameter for each mass state in which a plurality of reference masses are attached to a tool mounting part for attaching the tool or a workpiece mounting part for attaching the workpiece, the tool mounting part or the workpiece mounting part is oscillated in the same direction as oscillating hole machining by changing the relative movement speed between an upper limit relative movement speed and a lower limit relative movement speed, and the difference between the lower limit relative movement speed and the actual lower limit relative movement speed is minimized within a range in which the tool mounting part and the workpiece mounting part do not separate from each other; a second step of generating a first experimental information table consisting of a combination of a plurality of reference masses and a plurality of machine control parameters acquired for each reference mass; and when the machine tool receives a command to perform oscillating hole machining, A control method comprising: a third step of acquiring at least one mass information of the total mass of the tool mounting portion including the tool and the total mass of the workpiece mounting portion including the workpiece and mounting jig; and a fourth step of acquiring the machine control parameters corresponding to the mass information from the first experimental information table and setting them as the machine control parameters for oscillating hole machining.

2. The control method according to claim 1, wherein the machine control parameter includes one of a feedforward coefficient, a gain, or an acceleration / deceleration parameter for controlling oscillation.

3. A control method for oscillating hole machining in a machine tool, in which the relative position and relative movement speed of the tool and the workpiece are changed moment by moment within a range in which the tool and the workpiece do not separate from each other while the tool and the workpiece are rotating, comprising: a first step of acquiring a reference upper limit oscillation frequency for a plurality of reference speed command values, which is the maximum oscillation frequency within a mechanically operable range when a reference object is placed on a tool mounting part for mounting the tool or a workpiece mounting part for mounting the workpiece and oscillated; a second step of generating a second experimental information table consisting of a plurality of reference speed command values ​​and a plurality of reference upper limit oscillation frequencies corresponding to the plurality of reference speed command values; a third step of acquiring a speed command value and a command oscillation frequency for oscillating hole machining when the machine tool receives a command for oscillating hole machining and performs oscillating hole machining; and a fourth step of acquiring the reference upper limit oscillation frequency corresponding to the speed command value for oscillating hole machining from the second experimental information table and setting it as the upper limit oscillation frequency for oscillating hole machining. A control method comprising: a fifth step of changing the oscillation frequency in the oscillating hole machining to the upper limit oscillation frequency when the command oscillation frequency is greater than the upper limit oscillation frequency.

4. The control method of claim 3, characterized in that the reference mounting object has the maximum mass that can be attached to the tool mounting portion or the workpiece mounting portion.

5. The control method according to claim 3, wherein in the first step, a reference speed command value and a corresponding reference upper limit oscillation frequency are obtained for a plurality of reference mounts having different masses; in the second step, a third experimental information table is generated consisting of combinations of the masses of the plurality of reference mounts, a plurality of reference speed command values, and a plurality of corresponding reference upper limit oscillation frequencies; in the third step, at least one mass information of the mass of the tool mounting part and the mass of the workpiece mounting part is obtained; and in the fourth step, the reference upper limit oscillation frequency corresponding to the mass information and the speed command value for machining the oscillating hole is obtained from the third experimental information table and set as the upper limit oscillation frequency for machining the oscillating hole.

6. The control method according to claim 1 or 3, wherein generating the oscillating hole machining program includes at least the steps of: acquiring command information including the rotational speed of either the spindle on which the tool is mounted or the workpiece, a speed command value, the number of tool teeth, and the depth of the hole in the machining area; determining the oscillation frequency based on the rotational speed and the number of tool teeth; determining the number of blocks per oscillation period in the oscillating hole machining program based on a given reference time which is an interval at which block commands of the oscillating hole machining program can be read and the oscillation frequency; and generating a point cloud program that changes the relative position and relative movement speed of the tool and the workpiece moment by moment within a range in which the tool and the workpiece do not separate from each other, based on the number of blocks, the speed command value, and the depth of the hole.

7. A control device that performs the control method described in any one of claims 1 to 6.

8. A machine tool comprising the control device described in claim 7, a spindle, a table, and a feed axis.

9. A control method for oscillating turning in a machine tool, in which turning is performed by varying the relative movement speed of a tool and a rotating workpiece along the feed direction, comprising: a first step of acquiring a machine control parameter for each mass state, in which a plurality of reference masses are attached to a tool mounting section for attaching the tool or a workpiece mounting section for attaching the workpiece, such that the tool mounting section or the workpiece mounting section is oscillated in the same direction as oscillating turning by varying the relative movement speed between an upper limit relative movement speed and a lower limit relative movement speed, and the difference between the lower limit relative movement speed and the actual lower limit relative movement speed is minimized within a range in which the tool mounting section and the workpiece mounting section do not separate from each other; a second step of generating a first experimental information table consisting of a combination of a plurality of reference masses and a plurality of machine control parameters acquired for each reference mass; and a third step of acquiring at least one mass information of the total mass of the tool mounting section including the tool and the workpiece mounting section including the workpiece and mounting jig when the machine tool receives a command for oscillating turning and performs oscillating turning, A control method characterized by comprising: a fourth step of obtaining the machine control parameters corresponding to the mass information from the first experimental information table and setting them as the machine control parameters in oscillating turning.

10. The control method according to claim 9, wherein the machine control parameter includes one of a feedforward coefficient, a gain, or an acceleration / deceleration parameter for controlling oscillation.

11. A control method for oscillating turning, in which a machine tool performs turning by varying the relative movement speed of a tool and a rotating workpiece along the feed direction, comprising: a first step of acquiring a reference upper limit oscillating frequency for a plurality of reference speed command values, which is the maximum oscillating frequency within a mechanically operable range when a reference object is placed on a tool mounting part for mounting the tool or a workpiece mounting part for mounting the workpiece and oscillated; a second step of generating a second experimental information table consisting of a combination of a plurality of reference speed command values ​​and a plurality of reference upper limit oscillating frequencies corresponding to the plurality of reference speed command values; a third step of acquiring a speed command value and a command oscillating frequency for oscillating turning when the machine tool receives a command for oscillating turning and performs oscillating turning; and a fourth step of acquiring the reference upper limit oscillating frequency corresponding to the speed command value for oscillating turning from the second experimental information table and setting it as the upper limit oscillating frequency in oscillating turning. A control method comprising: a fifth step of changing the oscillation frequency in oscillating turning to the upper limit oscillation frequency when the command oscillation frequency is greater than the upper limit oscillation frequency.

12. The control method of claim 11, characterized in that the reference mounting object has the maximum mass that can be attached to the tool mounting portion or the workpiece mounting portion.

13. The control method according to claim 11, wherein in the first step, a reference speed command value and a corresponding reference upper limit oscillation frequency are obtained for a plurality of reference mounts having different masses; in the second step, a third experimental information table is generated consisting of combinations of the masses of the plurality of reference mounts, a plurality of reference speed command values, and a plurality of corresponding reference upper limit oscillation frequencies; in the third step, at least one mass information of the mass of the tool mounting part and the mass of the workpiece mounting part is obtained; and in the fourth step, the reference upper limit oscillation frequency corresponding to the mass information and the speed command value for oscillating turning is obtained from the third experimental information table and set as the upper limit oscillation frequency for oscillating turning.

14. The control method according to claim 9 or 11, wherein generating the oscillating turning program includes at least the steps of: acquiring command information including the rotational speed of either the spindle on which the tool is mounted or the workpiece, a speed command value, the number of tool teeth, and the depth of the hole in the machining area; determining the oscillation frequency based on the rotational speed and the number of tool teeth; determining the number of blocks per oscillation period in the oscillating turning program based on a given reference time which is an interval at which block commands of the oscillating turning program can be read, and the oscillation frequency; and generating a point cloud program that changes the relative position and relative moving speed of the tool and the workpiece moment by moment within a range in which the tool and the workpiece do not separate from each other, based on the number of blocks and the speed command value.

15. A control device that performs the control method described in any one of claims 9 to 14.

16. A machine tool comprising the control device described in claim 15, a spindle, a table, and a feed axis.

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