Numerical control device, numerical control system, and numerical control method

Abstract

The present disclosure provides a numerical control device (1) that causes a machine tool to perform vibration cutting, and includes an operator instruction detection unit (411) and a vibration condition determination unit. The operator instruction detection unit (411) detects a chip breakage signal that notifies the occurrence of chip breakage and is input by an operator observing a workpiece during vibration cutting. Upon detecting the chip breakage signal, the vibration condition determination unit indicates the relationship between the vibration conditions, which are conditions for performing vibration cutting by the machine tool during vibration cutting, and servo information that indicates the status of servo motors (61x, 61z) that drive the machine tool, acquires servo status information recorded during vibration cutting, and determines the vibration conditions during vibration cutting based on the servo status information.

Description

[Technical Field]

[0001] The present disclosure relates to a numerical control device, a numerical control system, and a numerical control method for controlling a machine tool that performs vibration cutting. [Background technology]

[0002] When machining a workpiece with a machine tool, a machining method called vibration cutting is known in which the tool and workpiece are vibrated relative to each other in the machining feed direction to break up chips. In vibration cutting, chips are broken up by setting vibration conditions such as vibration amplitude and vibration frequency when vibrating the tool.

[0003] However, when vibrating the tool, the motor may not be able to keep up with the command value for the vibration amplitude, and the actual vibration amplitude may tend to be smaller than the command value, resulting in failure to break the chips. On the other hand, if the command value for the vibration amplitude is set too high, the load on the motor that vibrates the tool increases. Therefore, users must adjust the vibration amplitude to an optimal value. However, this requires repeated steps, such as inputting the amplitude-feed ratio, which is the ratio between the vibration amplitude and the tool feed amount per spindle rotation, and checking the data to see if the chips are being broken, which places a heavy burden on the user.

[0004] Various techniques have been proposed to reduce the burden on users when adjusting the vibration amplitude to an optimal value. For example, Patent Document 1 discloses a technique for calculating the difference between the feedback position of the feed axis and a command position, which is an ideal position, and correcting the amplitude feed ratio so that the position approaches the command position. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6843314 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above Patent Document 1, the user needs to set an ideal value for the amplitude feed ratio as a vibration condition in advance, which means that a process of obtaining the vibration condition before machining is required, which is a burden on the user.

[0007] The present disclosure has been made in view of the above, and aims to provide a numerical control device that can reduce the burden on a user when setting vibration conditions related to vibration cutting. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, the present disclosure provides a numerical control device that causes a machine tool to perform vibration cutting, and includes an operator instruction detection unit and a vibration condition determination unit. The operator instruction detection unit detects a chip breakage signal that notifies the occurrence of chip breakage and is input by an operator observing a workpiece during vibration cutting. Upon detecting the chip breakage signal, the vibration condition determination unit indicates the relationship between the vibration conditions that are conditions for performing vibration cutting by the machine tool during vibration cutting and servo information that indicates the state of a servo motor that drives the machine tool, acquires servo status information recorded during vibration cutting, and determines vibration conditions during vibration cutting based on the servo status information. [Effects of the Invention]

[0009] The numerical control device according to the present disclosure has the effect of reducing the burden on the user when setting vibration conditions related to vibration cutting. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic diagram showing the concept of vibration cutting [Figure 2] FIG. 1 is a diagram schematically illustrating an example of the configuration of a numerical control device according to a first embodiment. [Figure 3] FIG. 10 is a diagram showing an example of servo status information; [Figure 4]FIG. 10 is a diagram showing an example of the relationship between vibration amplitude and amplitude feed ratio. [Figure 5] FIG. 10 is a diagram showing an example of a relationship between first time-series feedback position data and second time-series feedback position data; [Figure 6] 1 is a flowchart showing an example of a procedure for a vibration condition determination method according to the first embodiment. [Figure 7] 1 is a flowchart showing an example of a procedure for a vibration condition determination method according to the first embodiment. [Figure 8] FIG. 1 is a diagram showing an example of the appearance of a numerical control system having a machine tool and a numerical control device. [Figure 9] FIG. 10 is a diagram for explaining another example of a method for determining an idiosyncratic interval in the numerical control device according to the first embodiment. [Figure 10] FIG. 10 is a diagram for explaining another example of a method for determining an idiosyncratic interval in the numerical control device according to the first embodiment. [Figure 11] FIG. 10 is a diagram schematically illustrating an example of the configuration of a numerical control device according to a second embodiment. [Figure 12] FIG. 10 is a diagram showing an example of servo status information; [Figure 13] 10 is a flowchart showing an example of a procedure of a vibration condition determination method according to a second embodiment. [Figure 14] 10 is a flowchart showing an example of a procedure of a vibration condition determination method according to a second embodiment. [Figure 15] FIG. 10 is a diagram schematically illustrating an example of the configuration of a numerical control system according to a third embodiment. [Figure 16] FIG. 1 is a diagram showing an example of a hardware configuration of a control calculation unit included in a numerical control device according to a first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A numerical control device, a numerical control system, and a numerical control method according to embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0012] Embodiment 1 FIG. 1 is a schematic diagram illustrating the concept of vibration cutting. As shown in FIG. 1, a machine tool 70 for vibration cutting includes a workpiece W (a workpiece) attached to a spindle 71 whose rotation axis is the Z-axis direction, and a cutting tool 72 positioned to protrude in the X-axis direction, perpendicular to the Z-axis. The workpiece W rotates as the spindle 71 rotates. The tool 72 is movable in the X-axis and Z-axis directions. During cutting, the tool 72 reciprocates, i.e., vibrates, in the Z-axis direction at a position where the tip of the tool 72 contacts the surface of the workpiece W. In this machine tool 70, the tool 72 is vibrated in the Z-axis direction in synchronization with the rotation of the spindle 71 to generate a miss-cut region during cutting. The tool 72 is then vibrated in the cutting direction while the feed axis of the tool 72 is vibrated. This creates a "miss-cut section" where the workpiece W and the tool 72 do not come into contact, resulting in the chips C being broken into small pieces.

[0013] Figure 2 is a diagram schematically showing an example of the configuration of a numerical control device according to embodiment 1. The numerical control (NC) device 1 is a computer that causes a machine tool 70, such as the one shown as an example in Figure 1, to perform machining, including vibration cutting, on a workpiece W using a tool 72. The numerical control device 1 performs machining of the workpiece W using the tool 72 by controlling two or more drive axes of the machine tool 70.

[0014] The numerical control device 1 includes an input operation unit 2, a display unit 3, and a control calculation unit 4. FIG. 2 shows the numerical control device 1 and a drive unit 6, which is a component that causes a machine tool 70 to perform machining. The drive unit 6 is connected to the control calculation unit 4. The numerical control device 1 generates various commands in accordance with a machining program. The numerical control device 1 controls the machine tool 70 by outputting the generated various commands to the drive unit 6. Note that the drive unit 6 may be an element independent of the machine tool 70.

[0015] The machine tool 70 cuts the workpiece W by bringing the tool 72 into contact with the workpiece W and causing relative movement between the tool 72 and the workpiece W. The machine tool 70 cuts the workpiece W to remove unnecessary portions from the workpiece W, thereby machining the workpiece W into a desired shape. In the first embodiment, the machine tool 70 machines the workpiece W using the tool 72 while moving the tool 72 and the workpiece W relative to each other using two or more drive axes. In the first embodiment, the machine tool 70 machines the workpiece W by, for example, rotating the workpiece W using the drive unit 6 and moving the tool 72 in two directions, the X-axis direction and the Z-axis direction, using the drive unit 6. In one example, the X-axis is a vertical axis. In one example, the Z-axis is an axis parallel to a horizontal plane. The X-axis and Z-axis are perpendicular to each other. Note that the X-axis is not limited to a vertical axis, and the Z-axis is not limited to an axis parallel to a horizontal plane. The X-axis and Z-axis can be set appropriately according to the configuration of the machine tool 70.

[0016] The drive unit 6 includes a servo motor 61x, a detector 62x, and an X-axis servo control unit 63x. The servo motor 61x constitutes an X-axis drive mechanism. The X-axis drive mechanism is a drive mechanism that drives a tool 72 that cuts the workpiece W or the workpiece W in the X-axis direction. In the first embodiment, the X-axis drive mechanism is a drive mechanism that drives the tool 72 in the X-axis direction. The servo motor 61x is a power source for the X-axis drive mechanism. The detector 62x detects the rotational position and rotational speed of the servo motor 61x. The detector 62x outputs position information indicating the rotational position of the servo motor 61x and speed information indicating the rotational speed of the servo motor 61x to the X-axis servo control unit 63x.

[0017] The numerical control device 1 outputs a command to drive the tool 72 in the X-axis direction to the X-axis servo control unit 63x. The X-axis servo control unit 63x performs feedback (FB) control of the servo motor 61x based on the command from the numerical control device 1 and position information and speed information from the detector 62x. The drive unit 6 operates the tool 72 in the X-axis direction by feedback control of the servo motor 61x.

[0018] The drive unit 6 also includes a servo motor 61z, a detector 62z, and a Z-axis servo control unit 63z. The servo motor 61z constitutes a Z-axis drive mechanism. The Z-axis drive mechanism is a drive mechanism that drives the tool 72 that cuts the workpiece W or the workpiece W in the Z-axis direction. In the first embodiment, the Z-axis drive mechanism is a drive mechanism that drives the tool 72 in the Z-axis direction. The servo motor 61z is a power source for the Z-axis drive mechanism. The detector 62z detects the rotational position and rotational speed of the servo motor 61z. The detector 62z outputs position information indicating the rotational position of the servo motor 61z and speed information indicating the rotational speed of the servo motor 61z to the Z-axis servo control unit 63z.

[0019] The numerical control device 1 outputs a command to drive the tool 72 in the Z-axis direction to the Z-axis servo control unit 63z. The Z-axis servo control unit 63z performs feedback control of the servo motor 61z based on the command from the numerical control device 1 and the position information and speed information from the detector 62z. The drive unit 6 operates the tool 72 in the Z-axis direction by feedback control of the servo motor 61z.

[0020] The machine tool 70 is equipped with one or more tool posts (not shown). A drive mechanism drives the tool post and a tool 72. The tool post and the tool 72 are driven objects driven by the drive mechanism. The tool 72 is attached to the tool post. The drive unit 6 is equipped with a set of a servo motor 61x, a detector 62x, and an X-axis servo control unit 63x, and a set of a servo motor 61z, a detector 62z, and a Z-axis servo control unit 63z, for each tool post.

[0021] The drive unit 6 also includes a spindle motor 61s, a detector 62s, and a spindle control unit 63s. The spindle motor 61s is a servo motor that rotates a spindle 71. The spindle 71 is an axis that rotates the workpiece W. The detector 62s detects the rotational position and rotational speed of the spindle motor 61s. The detector 62s outputs position information indicating the rotational position of the spindle motor 61s and speed information indicating the rotational speed of the spindle motor 61s to the spindle control unit 63s.

[0022] The numerical control device 1 outputs a command to rotate the spindle 71 to the spindle control unit 63s. The spindle control unit 63s performs feedback control of the spindle motor 61s based on the command from the numerical control device 1 and the position information and speed information from the detector 62s. The drive unit 6 rotates the workpiece W by feedback control of the spindle motor 61s.

[0023] The machine tool 70 may be one that machines one workpiece W, or one that machines two or more workpieces W simultaneously. When the machine tool 70 is one that machines two or more workpieces W simultaneously, the drive unit 6 is provided with two or more sets of spindle motor 61s, detector 62s, and spindle control unit 63s. When the machine tool 70 is one that machines two or more workpieces W simultaneously, the machine tool 70 is provided with, for example, two or more tool rests.

[0024] The input operation unit 2 is a means for inputting information to the control operation unit 4. The input operation unit 2 is composed of input means such as a keyboard, buttons, and a mouse. The input operation unit 2 receives information such as commands, machining programs, and parameters for the numerical control device 1 from an operator and inputs the information to the control operation unit 4.

[0025] The display unit 3 is a means for displaying information processed by the control calculation unit 4 on a display screen. The display unit 3 is configured with display means such as a liquid crystal display device. Here, a case will be described in which the display unit 3 is a liquid crystal display device directly connected to the numerical control device 1, but the display unit 3 may also be a display device or a display device of a computer connected to a communication network when the numerical control device 1 is connected to this communication network.

[0026] The control calculation unit 4 includes a data input / output control unit 41, a storage unit 42, a machine control signal processing unit 43, a programmable logic controller (PLC) 44, a machining program analysis processing unit 45, an interpolation processing unit 46, an acceleration / deceleration processing unit 47, and an axis data input / output unit 48. The PLC 44 may be disposed outside the control calculation unit 4.

[0027] The data input / output control unit 41 receives information input from the input operation unit 2 and stores the received information in the memory unit 42. The data input / output control unit 41 also controls the display unit 3 to display screen display data stored in a display data memory area 423 (described later) of the memory unit 42. The data input / output control unit 41 has an operator instruction detection unit 411. The operator instruction detection unit 411 detects a chip breakage signal that is input by an operator observing the workpiece W during vibration cutting by the machine tool 70 and notifies the occurrence of chip breakage. In the first embodiment, the chip breakage signal is input from the input operation unit 2.

[0028] The storage unit 42 is a means for storing data such as a non-volatile memory, a hard disk, an SSD (Solid State Drive), etc. The storage unit 42 has a parameter storage area 421, a machining program storage area 422, a display data storage area 423, a servo data storage area 424, and a shared area 425.

[0029] The parameter storage area 421 stores parameters and the like used in the processing of the control calculation unit 4. Specifically, the parameter storage area 421 stores control parameters for operating the numerical control device 1, servo parameters, tool data, and parameters related to vibration cutting.

[0030] The machining program storage area 422 stores a machining program, which is an NC program used to machine the workpiece W. The machining program in the first embodiment includes a movement command that is a command to move the tool 72, a rotation command that is a command to rotate the spindle 71, and a vibration cutting command that is a command to vibrate the tool 72.

[0031] The display data storage area 423 stores screen display data, which is data of a screen to be displayed on the display unit 3. The screen display data is data for displaying information on the display unit 3.

[0032] The servo data storage area 424 stores servo status information indicating the status of each servo motor 61x, 61z and spindle motor 61s related to vibration cutting during vibration cutting. The servo status information indicates the relationship between the vibration conditions, which are the conditions for performing vibration cutting by the machine tool 70 during vibration cutting, and servo information indicating the status of the servo motors 61x, 61z and spindle motor 61s that drive the machine tool 70, and is information recorded during vibration cutting. The servo status information is information used when determining the vibration conditions, which are the conditions for performing vibration cutting during vibration cutting by the machine tool 70. Specifically, the servo status information is information that chronologically records the vibration conditions and servo information indicating the status of the servo motors 61x, 61z and spindle motor 61s that drive the machine tool 70. In the first embodiment, an example is given in which the vibration condition is the amplitude feed ratio. The amplitude feed ratio is the ratio between the vibration amplitude and the movement amount of the tool 72 relative to the workpiece W per vibration.

[0033] The servo status information is information recorded in chronological order, in association with the amplitude feed ratio and servo data for two or more consecutive unit operation periods (two in the example of FIG. 3 ), which indicates the contact state of the tool 72 with the workpiece W during a unit operation period of the spindle 71 when the vibration amplitude is stable. The unit operation period of the spindle 71 is a period during which the spindle 71 periodically performs a predetermined operation, and in one example, is a period during which the spindle 71 makes one rotation. In the following, an example is given in which the unit operation period is a period during which the spindle 71 makes one rotation. The servo data is information that indicates whether the tool 72 is in contact with the workpiece W during one rotation of the spindle 71. An example of such servo data is feedback position data detected by the detectors 62x, 62z, and 62s.

[0034] In the following, an example will be given in which the servo data is feedback position data. When the servo data is feedback position data, the servo data is time-series data of feedback position data acquired at predetermined time intervals during one rotation of the spindle 71. The time-series feedback position data during one rotation of the spindle 71 is also referred to as time-series feedback position data or time-series feedback position data for one rotation of the spindle. By using two consecutive pieces of time-series feedback position data, it is possible to determine whether or not there is a miss-motion section in the trajectory of the tool 72 during one rotation of the spindle 71.

[0035] FIG. 3 is a diagram showing an example of servo status information. The servo status information is information that associates an amplitude-feed ratio, a vibration amplitude stable state, first servo data, and second servo data. The amplitude-feed ratio is stored as an amplitude-feed ratio set by a vibration cutting parameter reading unit 461 (described later) of the interpolation processing unit 46, or as an amplitude-feed ratio updated by an amplitude-feed ratio determination unit 463 (described later) of the interpolation processing unit 46. The vibration amplitude stable state is information indicating whether the vibration amplitude is stable. For example, if the vibration amplitude is unstable, "0" is stored, and if the vibration amplitude is stable, "1" is stored. The first servo data and second servo data are servo data for the servo motors 61x and 61z and the spindle motor 61s. The first servo data and second servo data are stored as two consecutive pieces of time-series feedback position data when the vibration amplitude is stable, i.e., when "1" is stored in the vibration amplitude stable state. The first servo data is the time-series feedback position data for the first spindle rotation when it is determined that the vibration amplitude is stable. The second servo data is time-series feedback position data for one spindle revolution following the first servo data. Hereinafter, one piece of data combining the amplitude feed ratio, vibration amplitude stable state, first servo data, and second servo data of the servo status information will be referred to as a record. In the example of FIG. 3, one record corresponds to one revolution of the spindle 71, so the first servo data and the second servo data are not stored simultaneously. Furthermore, the first servo data and the second servo data are not stored in a record when the vibration amplitude stable state is "0." Note that, although an example is shown in which feedback position data is used as the servo data, feedback current values ​​may also be used.

[0036] 2, the shared area 425 stores data that is temporarily used when each processing unit of the control and calculation unit 4 executes processing. In the following explanation, the data that is temporarily used by each processing unit passes through the shared area 425, but this explanation may be omitted for simplicity.

[0037] The servo data is acquired by a servo data acquisition unit 462 (described later) of the interpolation processing unit 46, and is temporarily stored as time-series data for one spindle revolution in the shared area 425. When the amplitude feed ratio determination unit 463 determines that the vibration amplitude has stabilized, it stores the two consecutive time-series data for one spindle revolution stored in the shared area 425 after the determination in the servo status information of the servo data storage area 424.

[0038] In the control calculation unit 4, the machine control signal processing unit 43, the machining program analysis processing unit 45, and the interpolation processing unit 46 are connected via a memory unit 42, and information is written and read via the memory unit 42. In the following explanation, when explaining the writing and reading of information between the machine control signal processing unit 43, the machining program analysis processing unit 45, and the interpolation processing unit 46, the fact that the memory unit 42 is involved may be omitted.

[0039] The machine control signal processing unit 43 is connected to the PLC 44 and receives signal information from the PLC 44, such as relays that operate the mechanisms of the machine tool 70. The machine control signal processing unit 43 writes the received signal information into the shared area 425 of the memory unit 42. This signal information is referenced by the interpolation processing unit 46 during machining operation. Furthermore, when an auxiliary command is output to the shared area 425 by the machining program analysis processing unit 45, the machine control signal processing unit 43 reads this auxiliary command from the shared area 425 and sends it to the PLC 44. An auxiliary command is a command other than a command that operates a drive axis, which is a numerically controlled axis. Examples of auxiliary commands are M-codes and T-codes.

[0040] The PLC 44 holds a ladder program that describes the machine operations to be executed by the PLC 44. When the PLC 44 receives an M code or T code, which is an auxiliary command of the machining program, from the machine control signal processing unit 43, it executes processing corresponding to the auxiliary command in accordance with the ladder program. After executing the processing corresponding to the auxiliary command, the PLC 44 sends a completion signal indicating that the processing corresponding to the auxiliary command has been completed to the machine control signal processing unit 43, in order to execute the next block of the machining program.

[0041] The machining program analysis processing unit 45 is connected to the memory unit 42. The machining program analysis processing unit 45 reads out the machining program from the machining program storage area 422 and performs analysis processing on each block of the machining program, i.e., each line of the machining program. In one example, the machining program analysis processing unit 45 analyzes G-codes, which are commands related to axis movement, vibration cutting, etc., T-codes, such as tool change commands, S-codes, which are spindle motor rotation speed commands, and M-codes, which are machine operation commands.

[0042] When a machining program includes a G-code, the machining program analysis processing unit 45 analyzes the G-code to generate movement conditions corresponding to the G-code and writes the movement conditions into the shared area 425. These movement conditions include the speed at which the tool post moves in each of the X-axis direction and the Z-axis direction, and the positions to which the tool post moves in each of the X-axis direction and the Z-axis direction.

[0043] Furthermore, when a G-code for vibration cutting is included in the machining program, the machining program analysis processing unit 45 analyzes the G-code to generate vibration conditions, which are conditions for vibration in vibration cutting corresponding to the G-code, and writes the vibration conditions to the shared area 425. The vibration conditions include, for example, the number of vibrations per one spindle rotation and an amplitude feed ratio. For example, the number of vibrations per one spindle rotation is the number of vibrations of the tool 72 while the spindle 71 rotates once during vibration cutting.

[0044] When an S code is included in a machining program, the machining program analysis processing unit 45 analyzes the S code to generate a rotation speed of the spindle 71 corresponding to the S code and writes the rotation speed of the spindle 71 in the shared area 425.

[0045] The interpolation processing unit 46 is connected to the storage unit 42 and the acceleration / deceleration processing unit 47. The interpolation processing unit 46 processes the G-code and issues a command to the drive unit 6 via the acceleration / deceleration processing unit 47 and the axis data input / output unit 48. Specifically, when the movement conditions and vibration conditions are written to the shared area 425, the interpolation processing unit 46 reads the movement conditions and vibration conditions from the shared area 425. Based on the read movement conditions and vibration conditions, the interpolation processing unit 46 generates an X-axis command vibration movement amount, which is a command for the vibration movement amount in the X-axis direction, and a Z-axis command vibration movement amount, which is a command for the vibration movement amount in the Z-axis direction. The interpolation processing unit 46 writes the generated command vibration movement amount to the shared area 425 and outputs the generated command vibration movement amount to the acceleration / deceleration processing unit 47.

[0046] The acceleration / deceleration processing unit 47 is connected to the interpolation processing unit 46 and the axis data input / output unit 48. The acceleration / deceleration processing unit 47 acquires the command vibration movement amount from the interpolation processing unit 46 and converts the command vibration movement amount into a movement command per unit time that takes acceleration / deceleration into consideration in accordance with a pre-specified acceleration / deceleration pattern. The acceleration / deceleration processing unit 47 outputs the movement command per unit time to the axis data input / output unit 48.

[0047] The axis data input / output unit 48 is connected to the acceleration / deceleration processing unit 47 and the driving unit 6. The axis data input / output unit 48 acquires a movement command per unit time from the acceleration / deceleration processing unit 47 and outputs the movement command per unit time to the driving unit 6. The axis data input / output unit 48 also acquires feedback position data from the driving unit 6 and outputs the feedback position data to the acceleration / deceleration processing unit 47. When the acceleration / deceleration processing unit 47 acquires the feedback position data from the axis data input / output unit 48, it outputs the acquired feedback position data to the interpolation processing unit 46.

[0048] The interpolation processing unit 46 includes a vibration cutting parameter reading unit 461 , a servo data acquiring unit 462 , and an amplitude feed ratio determining unit 463 .

[0049] The vibration cutting parameter reading unit 461 reads vibration conditions, which are the conditions for performing vibration cutting, and sets the read vibration conditions as parameters for the vibration cutting process. In the first embodiment, the vibration condition to be determined by the user is the amplitude-feed ratio. When starting to execute a machining program, the vibration cutting parameter reading unit 461 reads, as an initial value, the value of the amplitude-feed ratio that has been set in advance as a parameter, or the value of the amplitude-feed ratio obtained as a result of analyzing the machining program by the machining program analysis processing unit 45. The initial value of the amplitude-feed ratio is normally set to "1".

[0050] The servo data acquisition unit 462 acquires servo information of each servo motor 61x, 61z and spindle motor 61s related to vibration cutting during vibration cutting at a predetermined cycle via the axis data input / output unit 48 and the acceleration / deceleration processing unit 47. In this example, servo data is acquired as the servo information. Also, in this example, the servo data is time-series feedback position data for one rotation of the spindle. The feedback position data is position data detected by the detectors 62x, 62z, 62s. In one example, the servo data acquisition unit 462 acquires the feedback position data at a predetermined cycle via the axis data input / output unit 48 and the acceleration / deceleration processing unit 47, and temporarily stores a group of feedback position data acquired during one rotation of the spindle 71 in the shared area 425 as time-series feedback position data.

[0051] As described above, the servo data may be time-series feedback current values ​​for one rotation of the spindle. In this case, the servo data acquisition unit 462 acquires the feedback current values ​​of the servo motors 61x, 61z and the spindle motor 61s via the axis data input / output unit 48 and the acceleration / deceleration processing unit 47. The feedback current value of the X-axis drive mechanism is acquired from the servo motor 61x by the X-axis servo control unit 63x. The feedback current value of the Z-axis drive mechanism is acquired from the servo motor 61z by the Z-axis servo control unit 63z. The feedback current value of the spindle 71 is acquired from the spindle motor 61s by the spindle control unit 63s. The servo data acquisition unit 462 temporarily stores a group of feedback current values ​​acquired during one rotation of the spindle 71 in the shared area 425 as time-series feedback current values.

[0052] After the amplitude-feed ratio is set by the vibration cutting parameter reading unit 461 or after the amplitude-feed ratio is updated by the amplitude-feed ratio determining unit 463, the amplitude-feed ratio determining unit 463 determines from the servo data whether the vibration amplitude has stabilized. FIG. 4 is a diagram showing an example of the relationship between the vibration amplitude and the amplitude-feed ratio. In FIG. 4, the amplitude-feed ratio is 1.1 in section (a), and the vibration amplitude is stable. In this case, the vibration waveform is, for example, feedback position data in the Z-axis direction. In section (a), the peak-to-peak value Ha, which is the difference between the maximum and minimum values ​​of this vibration waveform, is constant, and the vibration waveform is stable.

[0053] Section (c) shows the state when the amplitude-feed ratio is changed from 1.1 to 1.2. In this case, the vibration amplitude of the vibration waveform gradually decreases, and then gradually increases when the amplitude-feed ratio is changed to 1.2. Section (b) shows the state when the amplitude-feed ratio is 1.2 and the vibration amplitude is stable. Even in section (b), the peak-to-peak value Hb of the vibration waveform remains constant.

[0054] Returning to Fig. 2, the amplitude-feed ratio determination unit 463 determines from the vibration waveform of the servo data whether the spindle 71 has made one or more revolutions with the vibration amplitude stable. If the spindle 71 has not made one or more revolutions with the vibration amplitude stable, the amplitude-feed ratio determination unit 463 inputs the value of the currently set amplitude-feed ratio into the amplitude-feed ratio of the servo status information in the servo data storage area 424, and inputs "0" into the vibration amplitude stable state, indicating that the vibration amplitude is not stable. In one example, this process is performed every time the spindle 71 makes one revolution.

[0055] When the spindle 71 has made one or more revolutions while the vibration amplitude is stable, the amplitude-feed ratio determination unit 463 inputs the value of the amplitude-feed ratio currently set as the amplitude-feed ratio of the servo status information in the servo data storage area 424, inputs "1" indicating that the vibration amplitude is stable as the vibration amplitude stable state, and inputs the latest servo data stored in the shared area 425 at that time as the first servo data or the second servo data. In one example, the amplitude-feed ratio determination unit 463 records, in one record, the servo data temporarily written in the shared area 425, which corresponds to one spindle revolution when it is determined that the vibration amplitude is stable while the vibration amplitude is stable, as the first servo data, and records the servo data corresponding to the next spindle revolution as the second servo data in the next record.

[0056] The amplitude-feed ratio determination unit 463 determines whether a chip break signal is detected from the operator observing the workpiece W while vibration cutting is being performed after the spindle 71 has rotated one or more revolutions while the vibration amplitude of vibration cutting is stable after the amplitude-feed ratio has been set or changed. If a chip break signal from the operator is not detected, the amplitude-feed ratio determination unit 463 adds a fixed number to the currently set amplitude-feed ratio. The fixed number is determined in advance. In one example, the fixed number can be "0.1."

[0057] When a chip breakage signal from the operator is detected, the amplitude-feed ratio determination unit 463 uses the pair of first and second servo data stored in the servo status information to determine, as the vibration condition for the vibration cutting being performed, the amplitude-feed ratio corresponding to the pair of servo data in which the missed interval occurred earliest among the pairs of servo data in which the missed interval for vibration cutting occurred. In other words, using the pair of first and second servo data stored in the servo status information, the amplitude-feed ratio determination unit 463 obtains the vibration condition corresponding to the pair of servo data in which the missed interval appears next to the pair of servo data in which the missed interval for vibration cutting is not present and which is closest to the time when the chip breakage signal was detected.

[0058] Specifically, the amplitude-feed ratio determiner 463 acquires a set of first servo data and second servo data at the time when the chip separation signal is input from the servo status information. The amplitude-feed ratio determiner 463 compares the first time-series feedback position data, which is the first servo data, with the second time-series feedback position data, which is the second servo data, during one rotation of the spindle 71. At this time, the amplitude-feed ratio determiner 463 aligns the rotation phase of the spindle 71 and compares the first time-series feedback position data with the second time-series feedback position data. Then, the amplitude-feed ratio determiner 463 determines whether the second time-series feedback position data is always greater than the first time-series feedback position data.

[0059] FIG. 5 is a diagram showing an example of the relationship between the first time-series feedback position data and the second time-series feedback position data. In FIG. 5, the horizontal axis represents the phase of the main shaft 71 (the rotation angle of the main shaft 71), and the vertical axis represents the feedback position. In FIG. 5(A), during one rotation of the main shaft 71, which is the unit operation period of the main shaft 71, the second time-series feedback position data is always greater than the first time-series feedback position data at the same phase of the main shaft 71. This indicates that no miss interval occurs during the operation period of the main shaft 71 corresponding to the second time-series feedback position data. On the other hand, in FIG. 5(B), there is a section where the second time-series feedback position data is smaller than the first time-series feedback position data at the same phase of the main shaft 71. This section indicates a miss interval.

[0060] In other words, the amplitude feed ratio determination unit 463 determines that no idle interval has occurred if the second time-series feedback position data is always greater than the first time-series feedback position data during one rotation of the spindle 71. In this case, the amplitude feed ratio determination unit 463 receives the chip breakage signal, but since no idle interval has occurred, it generates alarm information indicating that no chip breakage has occurred and stores this in the display data storage area 423. The data input / output control unit 41 displays the alarm information on the display unit 3.

[0061] Furthermore, the amplitude-feed ratio determiner 463 determines that an idling interval has occurred if there is an interval during which the second time-series feedback position data is smaller than the first time-series feedback position data during one rotation of the spindle 71. The occurrence of an idling interval indicates that chip separation has occurred. In this case, the amplitude-feed ratio determiner 463 traces back the servo data sets in the servo status information prior to the time when the chip separation signal was received, and identifies the oldest servo data set among the servo data sets in which an idling interval has occurred as the first idling interval. The amplitude-feed ratio determiner 463 then obtains from the servo status information the amplitude-feed ratio corresponding to the period during which the spindle 71 rotates once, which includes the identified first idling interval, and determines this as the amplitude-feed ratio for the vibration cutting currently being performed.

[0062] In the example of the servo status information in FIG. 3, the servo data sets Dc, Db, and Da that precede the servo data set Dd at the time the chip break signal was input are traced back in order to determine whether a miss interval has occurred. Here, it is assumed that a miss interval occurred in the servo data sets Dd, Dc, and Db, but not in the servo data set Da. In this case, the oldest servo data set Db among the servo data sets Dd, Dc, and Db in which a miss interval has occurred is identified as the first miss interval. Then, the amplitude-feed ratio "1.1" corresponding to this servo data set Db is read from the servo status information, and the amplitude-feed ratio "1.1" is determined. The determined value will be used as the amplitude-feed ratio for subsequent vibration cutting in the currently executed machining program.

[0063] As described above, upon detecting a chip breakage signal, the amplitude-feed ratio determiner 463 acquires servo status information recorded during vibration cutting, indicating the relationship between the vibration conditions under which vibration cutting is performed by the machine tool 70 and the servo information indicating the status of the servo motors 61x, 61z and the spindle motor 61s that drive the machine tool 70, and determines the vibration conditions during vibration cutting based on the servo status information. Specifically, the amplitude-feed ratio determiner 463 acquires the vibration conditions for vibration cutting corresponding to the servo information obtained by tracing back from the time the chip breakage signal was detected in accordance with preset conditions. Furthermore, the amplitude-feed ratio determiner 463 gradually changes the vibration conditions during vibration cutting by the machine tool 70 and records the vibration conditions and servo information in chronological order in the servo status information. Note that the amplitude-feed ratio determiner 463 in the first embodiment corresponds to the vibration condition determiner.

[0064] The following describes the operation of determining vibration conditions in the numerical control method in the numerical control device 1 according to embodiment 1. Figures 6 and 7 are flowcharts showing an example of the procedure of the vibration condition determining method according to embodiment 1.

[0065] First, the vibration cutting parameter reading unit 461 reads the amplitude-feed ratio and sets it as an initial value (step S11). Next, the numerical control device 1 starts vibration cutting using vibration conditions including the set amplitude-feed ratio (step S12). The amplitude-feed ratio is set in advance by a parameter or by a machining program. The initial value of the amplitude-feed ratio is usually set to "1". In addition, the servo data acquisition unit 462 acquires feedback position data and temporarily stores the time-series feedback position data for one spindle rotation in the shared area 425 as servo data (step S13).

[0066] Thereafter, the amplitude-feed ratio determination unit 463 uses the servo data acquired by the servo data acquisition unit 462 to determine whether the spindle 71 has rotated one revolution or more with the vibration amplitude stable (step S14). As described above, the amplitude-feed ratio determination unit 463 uses the time-series feedback position data of the vibration amplitude to determine whether the period during which the peak-to-peak value of the vibration waveform remains constant continues for at least the period during which the spindle 71 rotates one revolution or more.

[0067] If the spindle 71 has not made one or more revolutions while the vibration amplitude is stable (No in step S14), the amplitude-feed ratio determination unit 463 records the amplitude-feed ratio at this point in time and a vibration amplitude stable state indicating that the vibration amplitude is not stable in the servo status information of the servo data storage area 424 (step S15). In one example, as in record 301 of the servo status information shown in FIG. 3, a "1" is recorded in the amplitude-feed ratio and a "0" is recorded in the vibration amplitude stable state. Then, the process returns to step S13.

[0068] If the spindle 71 rotates one or more times while the vibration amplitude is stable (Yes in step S14), the amplitude feed ratio determination unit 463 records the amplitude feed ratio at this time, the vibration amplitude stable state indicating stability, the first servo data at this time, and the second servo data obtained in the next operating period of the first servo data in the servo status information of the servo data storage area 424 (step S16).

[0069] In one example, the amplitude-feed ratio determination unit 463 records "1" in the amplitude-feed ratio field, records "1" in the vibration amplitude stable state field, and records time-series feedback position data for one spindle rotation in the first servo data, as in record 302 of the servo status information shown in Fig. 3. The first servo data is the time-series feedback position data for one spindle rotation that was used at the time of determination and temporarily stored in shared area 425. After recording record 302, when the time-series feedback position data for the next spindle rotation is temporarily stored in shared area 425, the amplitude-feed ratio determination unit 463 records "1" in the amplitude-feed ratio field, records "1" in the vibration amplitude stable state field, and records time-series feedback position data for one spindle rotation in the second servo data, as in record 303 of the servo status information shown in Fig. 3.

[0070] The amplitude-feed ratio determination unit 463 then determines whether the operator has input a chip breakage signal indicating that chip breakage has occurred during vibration cutting (step S17). FIG. 8 is a diagram schematically illustrating an example of the exterior of a numerically controlled machine tool having a machine tool and a numerical control device. The numerically controlled machine tool 10 includes a machining area 11 where a workpiece W is machined by a machine tool 70, a numerical control device 1 that controls the operation of the machine tool 70, and a numerical control operation panel 2a corresponding to the input operation unit 2. The operator monitors the chip breakage status during vibration cutting in the machining area 11 of the machine tool 70 as shown in FIG. 8. The door to the machining area 11 is not shown in FIG. 8. In reality, the operator monitors the chip breakage status during vibration cutting through a transparent window provided in the door to the machining area 11. When chip breakage during machining is confirmed, the operator presses a predetermined key 21 on the keyboard of the numerical control operation panel 2a. Pressing this predetermined key 21 generates a chip breakage signal. The operator instruction detection unit 411 determines whether the signal input from the numerical control operation panel 2a is a chip breaking signal. If the detected signal is a chip breaking signal resulting from pressing a predetermined key 21, the operator instruction detection unit 411 notifies the amplitude feed ratio determination unit 463 of the chip breaking signal via the shared area 425. In this way, the amplitude feed ratio determination unit 463 determines whether a chip breaking signal has been input. In other words, the amplitude feed ratio determination unit 463 determines whether a chip breaking signal has been received from the operator. The processing of step S17 corresponds to the operator instruction detection step.

[0071] Returning to FIG. 6, if the chip breaking signal has not been input (No in step S17), the amplitude-feed ratio determination unit 463 adds a fixed number to the current amplitude-feed ratio (step S18), and the process returns to step S13. In the example of FIG. 3, 0.1 is added as the fixed number. The processes of steps S14, S15, S16, and S18 correspond to the servo status information recording step. In this way, the amplitude-feed ratio determination unit 463 gradually changes the vibration conditions during vibration cutting by the machine tool 70, and records the vibration conditions and servo information in chronological order in the servo status information.

[0072] If the chip separation signal is input (Yes in step S17), the amplitude feed ratio determination unit 463 uses the servo status information to compare the first servo data and the second servo data at the time the chip separation signal was input (step S19). The amplitude feed ratio determination unit 463 determines whether or not there is an idling interval as a result of the comparison (step S20). Specifically, as shown in FIG. 5(B), it determines whether or not there is an interval during one rotation of the spindle 71 in which the second time-series feedback position data in the same phase is smaller than the first time-series feedback position data. The interval in which the second time-series feedback position data is smaller than the first time-series feedback position data is the idling interval.

[0073] Here, another method for determining the miss-rotation section will be described. In the above description, feedback position data was used as the servo data, but feedback current values ​​may also be used separately or in addition to this. The feedback current values ​​are indicators of the loads on the servo motors 61x, 61z and the spindle motor 61s. In this case, the first servo data of the servo status information in FIG. 3 records first time-series feedback current values ​​for a first period, which is the period during which the spindle 71 makes one rotation when it is determined that the vibration amplitude has stabilized, and the second servo data records second time-series feedback current values ​​for a second period, which is the period during which the spindle 71 makes one rotation following the first period.

[0074] FIG. 9 is a diagram illustrating another example of a method for determining an idling interval in the numerical control device according to the first embodiment. FIG. 9 shows an example of a comparison result of servo data when it is determined that an idling interval has not occurred. (A) of FIG. 9 is a diagram showing an example of the relationship between the first time-series feedback position data and the second time-series feedback position data, with the horizontal axis indicating the phase of the main shaft 71 (the rotation angle of the main shaft 71) and the vertical axis indicating the feedback position. (B) of FIG. 9 is a diagram showing an example of the relationship between the first time-series feedback current value and the second time-series feedback current value, with the horizontal axis indicating the phase of the main shaft 71 (the rotation angle of the main shaft 71) and the vertical axis indicating the feedback current value. It is also assumed that the horizontal axes of (A) and (B) of FIG. 9 are the same.

[0075] As shown in FIG. 9A, there is no overlap between the waveform of the first time-series feedback position data included in the first servo data and the waveform of the second time-series feedback position data included in the second servo data. Also, as shown in FIG. 9B, both the first time-series feedback current value included in the first servo data and the second time-series feedback current value included in the second servo data are greater than the feedback current reference value and are constant across all spindle phases. This indicates that when vibration cutting is performed in the second period following the first period, the tool 72 is in direct contact with the body of the workpiece W for the entire second period, cutting the workpiece W, and there is no period during which the tool misses the workpiece W and breaks the chips C generated from the workpiece W during the first period. In FIG. 9B, the second time-series feedback current value and the first time-series feedback current value are the same value across all spindle phases, and the waveform representing the second time-series feedback current value overlaps with the waveform representing the first time-series feedback current value. Here, the feedback current reference value is a reference value for determining whether the tool 72 is in contact with the workpiece W.

[0076] In this way, the amplitude feed ratio determiner 463 determines that no idling interval has occurred based on the fact that there is no overlap between the waveform of the first time-series feedback position data and the waveform of the second time-series feedback position data, that the second time-series feedback current value is constant throughout the second period, etc. In the first embodiment, the amplitude feed ratio determiner 463 determines that no idling interval has occurred based on the comparison result of at least one of the time-series feedback position data and the time-series feedback current value. In other words, the amplitude feed ratio determiner 463 may determine that no idling interval has occurred using the time-series feedback position data, the time-series feedback current value, or the time-series feedback position data and the time-series feedback current value.

[0077] FIG. 10 is a diagram illustrating another example of a method for determining an idling interval in the numerical control device according to the first embodiment. FIG. 10 shows an example of a comparison result of servo data when it is determined that an idling interval has occurred. (A) of FIG. 10 is a diagram showing an example of the relationship between the first time-series feedback position data and the second time-series feedback position data, with the horizontal axis indicating the phase of the main shaft 71 (the rotation angle of the main shaft 71) and the vertical axis indicating the feedback position. (B) of FIG. 10 is a diagram showing an example of the relationship between the first time-series feedback current value and the second time-series feedback current value, with the horizontal axis indicating the phase of the main shaft 71 (the rotation angle of the main shaft 71) and the vertical axis indicating the feedback current value. It is also assumed that the horizontal axes of (A) and (B) of FIG. 10 are the same.

[0078] As shown in (A) of FIG. 10, there is an overlap between the waveform of the first time-series feedback position data included in the first servo data and the waveform of the second time-series feedback position data included in the second servo data. Specifically, during periods T1 and T2, there is an overlap between the waveform of the first time-series feedback position data and the waveform of the second time-series feedback position data. Also, as shown in (B) of FIG. 10, the first time-series feedback current value included in the first servo data is greater than the feedback current reference value and is constant across all spindle phases. Meanwhile, during periods T1 and T2 where there is an overlap in the time-series feedback position data, the second time-series feedback current value included in the second servo data is smaller than the first time-series feedback current value and is below the feedback current reference value in some sections. This is thought to be because, when the workpiece W and the tool 72 are not in contact, the loads on the servo motors 61x, 61z and the spindle motor 61s are reduced, resulting in a smaller feedback current value.

[0079] In this way, the amplitude feed ratio determiner 463 determines that a swing-out interval has occurred based on, for example, the presence of an overlap between the waveform of the first time-series feedback position data and the waveform of the second time-series feedback position data, or the second time-series feedback current value being lower than the first time-series feedback current value during a portion of the second period. Note that in the first embodiment, the amplitude feed ratio determiner 463 determines that a swing-out interval has occurred based on a comparison result of at least one of the time-series feedback position data and the time-series feedback current value. In other words, the amplitude feed ratio determiner 463 may determine that a swing-out interval has occurred using the time-series feedback position data, the time-series feedback current value, or both the time-series feedback position data and the time-series feedback current value.

[0080] In the above determination method, if the feedback current value is negative, the magnitude of the absolute value of the feedback current value is used. Also, when at least one of feedback position data and feedback current value is used as servo data, a reference time may be set to deal with noise when making the determination. The above determination method makes it possible to more reliably determine whether a swing-out interval has occurred.

[0081] Returning to FIG. 7 , if no idle section has occurred (No in step S20), this means that even though the operator determined that chip breakage had occurred and pressed the key 21, no chip breakage has occurred. In this case, the amplitude / feed ratio determination unit 463 generates alarm information indicating that chip breakage has not occurred (step S21) and stores the alarm information in the display data storage area 423. The data input / output control unit 41 displays the alarm information stored in the display data storage area 423 on the display unit 3 (step S22). In one example, an alarm message indicating that chip breakage has not occurred is displayed on the display unit 3 in FIG. 1. This allows the operator to check for erroneous key operation. Here, the amplitude / feed ratio determination unit 463 may not terminate the process, but may continue the process by selecting NC parameters, etc. In this case, after viewing the alarm message, the operator presses the key 21 again when chip breakage is confirmed. The amplitude / feed ratio determination unit 463 then determines the idle section and determines the vibration conditions (amplitude / feed ratio).

[0082] Furthermore, if an idling interval occurs (Yes in step S20), the amplitude-feed ratio determination unit 463 identifies the first idling interval using the first servo data and second servo data set in the servo status information that precedes the time when the operator pressed the key 21, i.e., the time when the chip break signal was input (step S23). Specifically, the amplitude-feed ratio determination unit 463 determines whether an idling interval exists based on the first time-series feedback position data and the second time-series feedback position data of the servo data set that precedes the time when the chip break signal was input. If an idling interval exists, the servo data sets in the servo status information are further traced back until a servo data set that does not have an idling interval is found. Then, the servo data set immediately following the servo data set that was initially determined not to have an idling interval becomes the data that has the first idling interval.

[0083] 3, it is determined whether or not there is an idling interval for the servo data sets Dc, Db, and Da that precede the servo data set Dd at the time when the chip separation signal is input. If there is an idling interval for the servo data sets Dc and Db, but there is no idling interval for the servo data set Da, the servo data set that has the first idling interval is the servo data set Db.

[0084] Thereafter, the amplitude-feed ratio determination unit 463 acquires the amplitude-feed ratio corresponding to the set of servo data identified as having the miss section first (step S24), and determines the acquired amplitude-feed ratio as the amplitude-feed ratio for the current vibration cutting processing (step S25). The processing of steps S19, S20, S23, S24, and S25 corresponds to the vibration condition determination step.

[0085] In the example of Fig. 3, the amplitude-feed ratio of the servo data set Db having the first miss section is acquired as "1.1", and this "1.1" is determined as the amplitude-feed ratio. This completes the method for determining vibration conditions.

[0086] The determination in step S14 as to whether the main shaft 71 has made one or more revolutions while the vibration amplitude is stable is performed for each unit operation period of the main shaft 71, that is, for each revolution of the main shaft 71. Also, although an example has been described in which servo data is acquired at the cycle of the number of revolutions of the main shaft 71, servo data may also be acquired at other cycles.

[0087] The amplitude-feed ratio determined in the first embodiment may be stored in the storage unit 42 by the amplitude-feed ratio determination unit 463. In this case, it is desirable that the stored amplitude-feed ratio be associated with the corresponding vibration conditions. This makes it possible to use the amplitude-feed ratio value stored in the storage unit 42 based on the vibration conditions commanded by the machining program when performing vibration cutting processing next time and thereafter. In one example, if the commanded vibration conditions are exactly the same as the previous time, the amplitude-feed ratio determination unit 463 does not determine the amplitude-feed ratio by comparing the servo data shown in Figures 6 and 7, but sets the same amplitude-feed ratio value as the previous time. This method allows vibration cutting processing to be performed more efficiently.

[0088] Up to this point, we have explained that vibration cutting is performed while changing the vibration conditions (amplitude / feed ratio) and the vibration conditions (amplitude / feed ratio) are determined by the operator's chip breaking signal, but the vibration conditions (amplitude / feed ratio) may also be determined in a different way.

[0089] In one example, the vibration conditions (amplitude / feed ratio) are fixed, and the operator observes chip breakage during vibration cutting and inputs whether or not chip breakage has occurred using the keys 21 on the numerical control operation panel 2a, which is the input operation unit 2. Here, it is assumed that the corresponding keys 21 are determined in advance by parameters, etc. When a key input for chip breakage is made, the amplitude / feed ratio determination unit 463 determines the vibration conditions (amplitude / feed ratio) using servo status information, as described in the first embodiment. On the other hand, when a key input for chip breakage or not is made, the amplitude / feed ratio determination unit 463 changes the vibration conditions (amplitude / feed ratio) by a value determined in advance by parameters, etc. Then, the operator again observes chip breakage during vibration cutting under the changed vibration conditions (amplitude / feed ratio) and inputs whether or not chip breakage has occurred. By repeating this process at the operator's own pace, that is, by carefully observing chip breakage, the vibration conditions (amplitude / feed ratio) can be reliably determined.

[0090] As described above, the numerical control device 1 according to the first embodiment is a numerical control device 1 that causes the machine tool 70 to perform vibration cutting, and includes an operator instruction detection unit 411 and a vibration condition determination unit. The operator instruction detection unit 411 detects a chip breakage signal that notifies the occurrence of chip breakage, input by an operator observing the workpiece during vibration cutting. Upon detecting the chip breakage signal, the vibration condition determination unit indicates the relationship between the vibration conditions, which are the conditions for performing vibration cutting by the machine tool 70 during vibration cutting, and servo information that indicates the status of the servo motors 61x, 61z and spindle motor 61s that drive the machine tool 70, acquires the servo status information recorded during vibration cutting, and determines the vibration conditions during vibration cutting based on the servo status information.

[0091] Furthermore, the numerical control method according to the first embodiment is a numerical control method in a numerical control device 1 that causes a machine tool 70 to perform vibration cutting, and includes an operator instruction detection step and a vibration condition determination step. In the operator instruction detection step, the numerical control device 1 detects a chip breakage signal that notifies the occurrence of chip breakage, input by an operator observing the workpiece during vibration cutting. In the vibration condition determination step, upon detecting the chip breakage signal, the numerical control device 1 obtains servo status information recorded during vibration cutting, indicating the relationship between the vibration conditions that are conditions for performing vibration cutting by the machine tool 70 during vibration cutting and servo information that indicates the status of the servo motors 61x, 61z and spindle motor 61s that drive the machine tool 70, and determines the vibration conditions during vibration cutting based on the servo status information.

[0092] This allows the operator to visually confirm chip breakage during vibration cutting, i.e., to determine the vibration cutting conditions using a notification regarding the operator's instructions as a trigger. Therefore, the process of the operator obtaining ideal vibration conditions before machining can be eliminated. In other words, the numerical control device 1 and numerical control method according to the first embodiment do not require the operator to set vibration conditions in advance, thereby solving the problem of having to confirm pre-determined vibration conditions through trial machining, etc. In one example, the process of the operator setting vibration cutting parameters and the trial vibration cutting process can be omitted. As a result, the burden on the operator in machining setup, etc. can be reduced, contributing to improved productivity. In other words, the burden on the user when setting vibration conditions for vibration cutting can be reduced.

[0093] Furthermore, since the servo data is compared after receiving a chip breakage signal from the operator indicating that chip breakage has occurred, the processing load of the numerical control device 1 can be reduced compared to when servo data is compared for each process.

[0094] The vibration condition determination unit acquires vibration conditions for vibration cutting corresponding to servo information going back in time from the time when the chip break signal was detected in accordance with preset conditions. This makes it possible to identify the oldest set of servo data among sets of servo data in which a miss interval occurs before the time when the chip break signal was received as the first miss interval.

[0095] Furthermore, the vibration condition determination unit gradually changes the vibration conditions during vibration cutting by the machine tool 70, and records the vibration conditions and servo information in chronological order in the servo status information. By gradually changing the vibration conditions, it becomes possible to more accurately determine the vibration conditions of vibration cutting at the time when the chip breakage signal is detected.

[0096] The numerical control device 1 according to the first embodiment further includes a servo data acquisition unit 462 that acquires servo information at a predetermined cycle. The machine tool 70 includes a spindle 71 that rotates the workpiece, and servo motors 61x, 61z and a spindle motor 61s that vibrate at least one of the workpiece and the tool 72 that machines the workpiece. The servo information is servo data that can determine whether the tool 72 is in contact with the workpiece during a unit operation period of the spindle 71. The vibration condition determination unit records the first and second servo data, which are servo data for two consecutive unit operation periods when the operation of the spindle 71 is stable, in the servo status information, and then changes the vibration conditions. When the vibration condition determination unit detects a chip breakage signal, it uses the pair of first and second servo data stored in the servo status information to acquire vibration conditions corresponding to the pair of servo data that includes an idling interval in vibration cutting that appears next to the pair of servo data that does not include an idling interval in vibration cutting closest to the time when the chip breakage signal was detected. In this way, when the operator confirms the occurrence of chip breakage during vibration cutting and notifies the numerical control device 1, the vibration conditions are adjusted by comparing the sets of servo data acquired from the drive unit 6, so the operator can determine the vibration conditions without having to set parameters or perform trial cutting. As a result, the burden on the operator can be reduced and productivity can be improved.

[0097] Furthermore, in the numerical control device 1 according to the first embodiment, when the vibration condition determination unit determines that there is no idling section using the first servo data and the second servo data after the chip breakage signal is detected, it generates alarm information indicating that chip breakage has not occurred. This makes it possible to check for erroneous key operations by the operator.

[0098] Furthermore, in the numerical control device 1 according to the first embodiment, the servo data is feedback position data, which is a position detected by detectors 62x, 62z, 62s attached to the servo motors 61x, 61z and the spindle motor 61s, or feedback current values, which are current values ​​detected by the servo control unit and the spindle control unit 61s that control the servo motors 61x, 61z and the spindle motor 61s. These data are information that indicates whether or not the tool 72 is in contact with the workpiece W, and therefore it is possible to detect an idling section using the first servo data and the second servo data.

[0099] Furthermore, in the numerical control device 1 according to the first embodiment, the vibration condition is the amplitude-feed ratio, which is the ratio between the amplitude of vibration and the amount of movement of the tool 72 that processes the workpiece relative to the workpiece per vibration. By changing the amplitude-feed ratio, it is possible to change whether or not chip breakage occurs. This allows the operator to reliably determine the conditions for chip breakage in vibration cutting. This makes it easy for the operator to adjust the vibration conditions for vibration cutting.

[0100] Embodiment 2 11 is a diagram schematically illustrating an example of the configuration of a numerical control device according to the second embodiment. The same components as those in the first embodiment are given the same reference numerals, and their description will be omitted, and only the parts that differ from the first embodiment will be described. The numerical control device 1A according to the second embodiment differs from the first embodiment in the configuration of an interpolation processing unit 46A of a control calculation unit 4A. Also, the servo status information stored in the servo data storage area 424 of the storage unit 42 differs from the first embodiment.

[0101] FIG. 12 is a diagram showing an example of servo status information. The servo status information of the second embodiment includes the number of spindle rotations in addition to the amplitude feed ratio, the vibration amplitude stable state, the first servo data, and the second servo data. The number of spindle rotations is information indicating, for example, the number of rotations of the spindle 71 since machining began. The number of spindle rotations is an example of servo information indicating the status of the servo motors 61x, 61z and the spindle motor 61s. Note that the rest is the same as FIG. 3 of the first embodiment, so a description thereof will be omitted.

[0102] Returning to FIG. 11, the interpolation processing unit 46A further includes a visual stimulus response time correction unit 464. There is a time lag between when the operator visually confirms chip breakage and when he or she moves his or her finger and presses the key 21 on the numerical control operation panel 2a, which is the input operation unit 2. This time lag is called the visual stimulus response time, and is generally said to be a delay time of about 250 ms. Therefore, in the second embodiment, the visual stimulus response time correction unit 464 calculates the number of rotations of the spindle 71 during the visual stimulus response time, and uses the calculated number of rotations to calculate the number of spindle rotations at the time when the operator confirms that chip breakage of the desired length has occurred.

[0103] Specifically, the visual stimulus reaction time correction unit 464 calculates the corrected number of spindle rotations by subtracting the number of spindle rotations during the visual stimulus reaction time from the number of spindle rotations at the time when a chip breakage signal indicating that chip breakage of the desired length has occurred is received from the operator. The corrected number of spindle rotations is the number of spindle rotations at the time when the operator determines that chip breakage has occurred. The visual stimulus reaction time correction unit 464 then outputs the corrected number of spindle rotations to the amplitude feed ratio determination unit 463. Here, the number of spindle rotations is based on the time when vibration cutting starts.

[0104] The amplitude-feed ratio determination unit 463 uses the data stored in the servo status information to obtain the amplitude-feed ratio corresponding to the corrected number of spindle rotations, and determines this amplitude-feed ratio as the amplitude-feed ratio for the vibration cutting currently being performed. In the second embodiment, the amplitude-feed ratio determination unit 463 and the visual stimulus reaction time correction unit 464 correspond to the vibration condition determination unit.

[0105] A specific example of a method for correcting the number of spindle rotations in the visual stimulus reaction time correction unit 464 will be described. The number of spindle rotations N' at the time when chip breakage of the desired length occurs for the operator is calculated by the following formula (1). Here, the number of spindle rotations at the time when a key operation by the operator is detected is taken as Na, and the command spindle rotation speed during vibration cutting is taken as M [r / min]. The time when the key operation is detected can, for example, be the time when the chip breakage signal is received.

[0106] N'=Na-M / 60×250 / 1000 (1)

[0107] In equation (1), the visual stimulus reaction time is set to a typical value of 250 [ms]. However, if the visual stimulus reaction time differs depending on the operator, the visual stimulus reaction time may be changed to suit the operator. In this case, the number of spindle rotations N' at the time when chip breakage of the desired length occurs for the operator is calculated using the following equation (2). However, the visual stimulus reaction time of the operator is set to P [ms]. Because a visual stimulus reaction time with a smaller error is used, it is possible to improve the calculation accuracy of the number of spindle rotations at the time when chip breakage of the desired length occurs for the operator.

[0108] N' = Na - M / 60 × P / 1000 (2)

[0109] Next, a description will be given of the operation of determining a vibration condition in the numerical control method in the numerical control device 1A according to embodiment 2. Figures 13 and 14 are flowcharts showing an example of the procedure of the method of determining a vibration condition according to embodiment 2.

[0110] First, the vibration cutting parameter reading unit 461 reads the amplitude-feed ratio and sets it as an initial value (step S31). Then, the numerical control device 1A starts vibration cutting using vibration conditions including the set amplitude-feed ratio (step S32). Next, the amplitude-feed ratio determining unit 463 records the number of spindle rotations since the start of vibration cutting in the servo status information (step S33). In addition, the servo data acquiring unit 462 acquires feedback position data and temporarily stores the time-series feedback position data in a unit operation period of the spindle 71 as servo data in the shared area 425 (step S34). The unit operation period of the spindle 71 is, for example, the period during which the spindle 71 rotates once.

[0111] Thereafter, the amplitude-feed ratio determination unit 463 determines whether a chip breaking signal has been input, which notifies the operator that chips of the desired length have been broken (step S35). If the chip breaking signal has not been input (No in step S35), the amplitude-feed ratio determination unit 463 uses the servo data acquired by the servo data acquisition unit 462 to determine whether the spindle 71 has made one or more revolutions with the vibration amplitude stable (step S36).

[0112] If the spindle 71 has not made one or more revolutions while the vibration amplitude is stable (No in step S36), the amplitude-feed ratio determination unit 463 records the amplitude-feed ratio and the vibration amplitude stable state, which indicates that the vibration amplitude is not stable, in association with the number of spindle revolutions at this time in the servo status information in the servo data storage area 424 (step S37).Then, the process returns to step S33.

[0113] Furthermore, if the spindle 71 has made one or more revolutions while the vibration amplitude is stable (Yes in step S36), the amplitude-feed ratio determination unit 463 records the amplitude-feed ratio, vibration amplitude stability information indicating stability, the first servo data at this time, and the second servo data acquired in the next unit operation period of the first servo data, in the servo status information of the servo data storage area 424, in association with the number of spindle rotations at this time (step S38). Thereafter, the amplitude-feed ratio determination unit 463 adds a fixed number to the current amplitude-feed ratio (step S39), and the process returns to step S33. In the example of FIG. 12, 0.1 is added as the fixed number.

[0114] If a chip breakage signal is input in step S35 (Yes in step S35), the visual stimulus reaction time correction unit 464 calculates the corrected number of spindle rotations at the time the operator confirmed chip breakage, taking into account the visual stimulus reaction time (step S40).

[0115] A specific example of the calculation of the corrected spindle rotation number will be explained using Figure 12. Assume that the spindle rotation number M during vibration cutting is 5000 [r / min]. The timing when the operator recognizes that chip breakage of the desired length has occurred and performs a key operation is assumed to be equal to the time when the chip breakage signal is input, and in this case, the chip breakage signal is input at record De1. The spindle rotation number at this time is "64". In other words, the spindle rotation number Na at the time the operator's key operation is detected is "64". From the above, by using equation (1), the spindle rotation number N' when chip breakage of the operator's desired length occurs can be calculated using the following equation (3).

[0116] N'=64-5000 / 60×250 / 1000=43 (3)

[0117] In other words, the operator judges that the chip C is of the desired length at record De2 of the servo status information in Fig. 12. The value of the number of spindle rotations at this time, "43", becomes the corrected number of spindle rotations.

[0118] Returning to FIG. 13, the visual stimulus reaction time correction unit 464 outputs the corrected number of spindle rotations to the amplitude-feed ratio determination unit 463. Thereafter, the amplitude-feed ratio determination unit 463 uses the data accumulated in the servo status information to obtain the amplitude-feed ratio corresponding to the corrected number of spindle rotations (step S41). Then, the amplitude-feed ratio determination unit 463 determines the obtained amplitude-feed ratio as the amplitude-feed ratio for the current vibration cutting processing (step S42). In the example of FIG. 12, the amplitude-feed ratio corresponding to the corrected number of spindle rotations "43" is "1.3", so this "1.3" is determined as the amplitude-feed ratio. This completes the method for determining vibration conditions.

[0119] After acquiring the amplitude feed ratio in step S41, it is also possible to determine the amplitude feed ratio in step S42 after confirming whether an idling interval has occurred, which is an interval in which the second feedback position in the same phase is smaller than the first feedback position during a unit operation period of the spindle 71 when the vibration amplitude is at a stable amplitude feed ratio. In this example, the unit operation period of the spindle 71 is the period during which the spindle 71 makes one rotation. Also, confirming whether an idling interval has occurred corresponds to confirming whether chip breakage has occurred. Here, if an idling interval has not occurred, the processing from step S21 to step S22 in FIG. 7 is executed.

[0120] Furthermore, the determination in step S36 as to whether the main shaft 71 has made one or more revolutions while the vibration amplitude is stable is performed for each unit operation period of the main shaft 71, in this example, for each revolution of the main shaft 71. Furthermore, although the case where servo data is acquired at the cycle of the number of revolutions of the main shaft 71 has been described as an example, servo data may also be acquired at other cycles. Furthermore, in the second embodiment, feedback current values ​​may be used as servo data instead of feedback position data.

[0121] Furthermore, similarly to the first embodiment, the amplitude-feed ratio determination unit 463 may associate the determined amplitude-feed ratio with the corresponding vibration conditions and store it in the storage unit 42. This makes it possible to use the amplitude-feed ratio value stored in the storage unit 42 based on the vibration conditions commanded by the processing program when performing vibration cutting machining from the next time onwards.

[0122] Furthermore, the numerical control device 1A may be configured to be able to select or switch between the method of determining the amplitude-feed ratio in embodiment 1 and the method of determining the amplitude-feed ratio in embodiment 2. The selection or switching may be performed by parameter settings of the numerical control device 1A, or by an input signal of a PLC signal or a machining program command.

[0123] In the numerical control device 1A according to the second embodiment, a machine tool 70 includes a spindle 71 that rotates a workpiece, and servo motors 61x, 61z, and a spindle motor 61s that vibrate at least one of the workpiece and a tool 72 that processes the workpiece. The servo information is the number of rotations of the spindle 71 since vibration cutting began. The vibration condition determination unit records the number of rotations of the spindle 71 in the servo status information as the servo information. Furthermore, upon detecting a chip breakage signal, the vibration condition determination unit uses the servo status information to calculate a corrected number of rotations of the spindle 71, which is calculated by retroactively calculating the number of rotations of the spindle 71 at the time the chip breakage signal was detected by a visual stimulus response time, which is the time between the operator's confirmation of chip breakage and the issuance of the chip breakage signal. The vibration condition determination unit then obtains vibration conditions corresponding to the corrected number of rotations of the spindle 71. This allows the operator to easily and reliably determine vibration conditions that break chips to the desired length.

[0124] The numerical control device 1A according to the second embodiment further includes a servo data acquisition unit 462 that acquires servo information at a predetermined interval. The servo information further includes servo data that can determine whether the tool 72 is in contact with the workpiece during a unit operation period of the spindle 71. The vibration condition determination unit records the first and second servo data, which are servo data for two consecutive unit operation periods when the spindle 71 is operating stably, in the servo status information, and then changes the vibration conditions. Furthermore, when the vibration condition determination unit detects a chip breakage signal, if it determines using the first and second servo data that there is no idle period in vibration cutting, it generates alarm information indicating that chip breakage has not occurred. This allows for checking for incorrect key operation by the operator.

[0125] Embodiment 3 FIG. 15 is a diagram schematically illustrating an example of the configuration of a numerical control system according to the third embodiment. The numerical control system 80 includes a numerically controlled machine tool 10, a communication terminal 81, and a relay device 82. The numerically controlled machine tool 10 includes the numerical control device 1, 1A described in the first and second embodiments and a machine tool 70, and is a device that performs vibration cutting of a workpiece W according to a machining program. The numerically controlled machine tool 10 also includes a wireless data input / output unit (not shown) and a wireless antenna (not shown), and is configured to be capable of wireless communication. The wireless data input / output unit and the wireless antenna constitute a communication unit.

[0126] The communication terminal 81 is an information processing device having a communication unit such as a smartphone, tablet terminal, or personal computer. The relay device 82 is a device that relays data transmission and reception via wireless communication between the numerically controlled machine tool 10 and the communication terminal 81. Here, wireless communication can be performed using a wireless LAN (Local Area Network) such as Wi-Fi (registered trademark) (Wireless Fidelity) communication, mobile communication, Bluetooth (registered trademark) communication, or the like. Fig. 15 shows an example in which the numerically controlled machine tool 10, the communication terminal 81, and the relay device 82 are connected via Wi-Fi communication, and an example of the relay device 82 is a Wi-Fi router.

[0127] 15 shows an example of wireless communication, the numerically controlled machine tool 10, the communication terminal 81, and the relay device 82 may be connected by wired communication. In this case, the relay device 82 is a device such as a hub or a router. The numerically controlled machine tool 10, the communication terminal 81, and the relay device 82 may also be connected by wireless communication and wired communication. In other words, the numerical control system 80 may be configured so that the numerically controlled machine tool 10, the communication terminal 81, and the relay device 82 can communicate with each other via a network.

[0128] In a numerical control system 80 shown in FIG. 15, data communication is performed between a numerically controlled machine tool 10 and a communication terminal 81 using Wi-Fi communication via a Wi-Fi router, which is an example of a relay device 82.

[0129] In step S17 of Fig. 6 or step S35 of Fig. 13, the operator confirms chip breakage during vibration cutting and notifies the numerical control device 1, 1A of a chip breakage signal by operating the keyboard of the numerical control operation panel 2a of Fig. 8. However, in the case of a large numerically controlled machine tool 10, the size of the machine makes it difficult to see the state of the machining area 11 from the location of the numerical control operation panel 2a shown in Fig. 8. In other words, there are cases where the operator is unable to confirm chip breakage during vibration cutting.

[0130] Therefore, by configuring a numerical control system 80 as shown in Fig. 15, a communication terminal 81 that functions as the input operation unit 2 and the numerical control device 1, 1A of the numerically controlled machine tool 10 are connected via Wi-Fi. This allows the operator carrying the communication terminal 81 to freely move to a position where he or she can see the machining area 11. Then, while checking the state of the machining area 11, the operator can press a predetermined key on the communication terminal 81 to notify the numerical control device 1, 1A of a chip breakage signal indicating that chip breakage during vibration cutting has been confirmed.

[0131] However, in the case of mobile communications, delays occur depending on the radio wave conditions, the degree of congestion of mobile communications, etc. In other words, a delay greater than that described in the second embodiment may occur between the time when the operator confirms chip separation during vibration cutting, presses a predetermined key, and the time when the chip separation signal is input to the numerical control device 1, 1A. For this reason, in addition to the visual stimulus reaction time, a delay caused by the network may be corrected.

[0132] In a numerical control system 80 according to the third embodiment, the numerical control device 1, 1A according to the first or second embodiment is connected to an information processing device having a communication unit via a communication system. The numerical control device 1, 1A is equipped with a communication unit that communicates with the information processing device, and the information processing device can transmit a chip breaking signal to the numerical control device 1, 1A in response to an operation by an operator. This allows the operator to use the information processing device as the input operation unit 2. As a result, when the numerically controlled machine tool 10 on which the numerical control device 1, 1A is installed is a large device, the operator can move to a position where he or she can directly check chip breaking during vibration cutting and reliably notify the numerical control device 1, 1A of the chip breaking signal.

[0133] Next, the hardware configuration of the control calculation unit 4, 4A provided in the numerical control device 1, 1A described in each embodiment will be described. Since the hardware configuration of the control calculation unit 4, 4A provided in the numerical control device 1, 1A described in each embodiment is the same, the hardware configuration of the control calculation unit 4 provided in the numerical control device 1 according to the first embodiment will be described as an example.

[0134] FIG. 16 is a diagram illustrating an example of a hardware configuration of a control calculation unit included in the numerical control device according to the first embodiment.

[0135] The control calculation unit 4 is realized by a control circuit 100 shown in Fig. 16. The control circuit 100 includes a processor 101 and a memory 102. The control circuit 100 is a circuit in which the processor 101 executes software.

[0136] The control calculation unit 4 is realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in the memory 102. In the control circuit 100, the processor 101 reads and executes a computer program stored in the memory 102, thereby realizing each function of the control calculation unit 4. In other words, the control circuit 100 includes the memory 102 for storing a program that results in the processing of the control calculation unit 4. This program is a numerical control program that causes a computer to execute the procedures and methods of the control calculation unit 4. The memory 102 is also used as a temporary memory when the processor 101 executes various processes.

[0137] The processor 101 is a CPU (Central Processing Unit), a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a processor, a DSP (Digital Signal Processor), a system LSI (Large Scale Integration), etc. The memory 102 is, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), or an EEPROM (registered trademark) (Electrically Erasable Programmable Read Only Memory), or a magnetic disk, a flexible disk, an optical disk, a compact disk, a minidisk, or a DVD (Digital Versatile Disc), etc.

[0138] The program executed by the processor 101 may be a computer program product having a computer-readable, non-transitory recording medium that includes a plurality of instructions executable by a computer for performing data processing. The program executed by the processor 101 causes the computer to execute the plurality of instructions to perform data processing.

[0139] The control and calculation unit 4 may be realized by dedicated hardware. Alternatively, some of the functions of the control and calculation unit 4 may be realized by dedicated hardware, and other parts of the functions of the control and calculation unit 4 may be realized by software or firmware.

[0140] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention. [Explanation of symbols]

[0141] 1,1A numerical control device, 2 input operation unit, 2a numerical control operation panel, 3 display unit, 4,4A control calculation unit, 6 drive unit, 10 numerically controlled machine tool, 11 machining area, 21 key, 41 data input / output control unit, 42 memory unit, 43 machine control signal processing unit, 44 PLC, 45 machining program analysis processing unit, 46,46A interpolation processing unit, 47 acceleration / deceleration processing unit, 48 axis data input / output unit, 61s spindle motor, 61x,61z servo motor, 62s,62x,62z detector, 63s spindle control unit, 63x X-axis servo control unit, 63z Z-axis servo control unit, 70 machine tool, 71 spindle, 72 tool, 80 numerical control system, 81 communication terminal, 82 relay device, 100 control circuit, 101 processor, 102 memory, 411 operator instruction detection unit, 421 Parameter storage area, 422 machining program storage area, 423 display data storage area, 424 servo data storage area, 425 shared area, 461 vibration cutting parameter reading unit, 462 servo data acquisition unit, 463 amplitude feed ratio determination unit, 464 visual stimulus reaction time correction unit, C chips, W workpiece.

Claims

1. A numerical control device that causes a machine tool to perform vibration cutting, an operator instruction detection unit that detects a chip breakage signal that is input by an operator observing the workpiece during vibration cutting and that notifies the operator of the occurrence of chip breakage; a vibration condition determination unit that, upon detecting the chip breakage signal, indicates the relationship between vibration conditions, which are conditions for performing vibration cutting by the machine tool during vibration cutting, and servo information indicating the state of a servo motor that drives the machine tool, acquires servo state information recorded during the execution of vibration cutting, and determines the vibration conditions during vibration cutting based on the servo state information; A numerical control device comprising:

2. 2. The numerical control device according to claim 1, wherein the vibration condition determination unit acquires vibration conditions for vibration cutting corresponding to the servo information at a point in time going back from the point in time when the chip breakage signal was detected according to preset conditions.

3. The numerical control device according to claim 1, characterized in that the vibration condition determination unit gradually changes the vibration conditions during the vibration cutting by the machine tool, and records the vibration conditions and the servo information in chronological order in the servo status information.

4. a servo data acquisition unit that acquires the servo information at a predetermined cycle; the machine tool has a spindle that rotates the workpiece, and the servo motor that vibrates at least one of the workpiece and a tool that processes the workpiece, the servo information is servo data that is information that can determine whether or not the tool is in contact with the workpiece during a unit operation period of the spindle, The vibration condition determination unit changing the vibration condition after recording the first servo data and the second servo data, which are the servo data in two consecutive unit operation periods while the operation of the spindle is stable, in the servo status information; 2. A numerical control device according to claim 1, characterized in that when the chip breakage signal is detected, the set of first servo data and second servo data stored in the servo status information is used to obtain the vibration condition corresponding to the set of servo data that includes an missed section of the vibration cutting that appears next to the set of servo data that does not include an missed section of the vibration cutting closest to the time when the chip breakage signal is detected.

5. 5. The numerical control device according to claim 4, wherein the vibration condition determination unit generates alarm information indicating that chip breakage has not occurred when, after the chip breakage signal is detected, it determines that the miss-swing section does not exist using the first servo data and the second servo data.

6. the machine tool has a spindle that rotates the workpiece, and the servo motor that vibrates at least one of the workpiece and a tool that processes the workpiece, the servo information is the number of rotations of the spindle since the vibration cutting started, The vibration condition determination unit The number of rotations of the spindle is recorded in the servo status information as the servo information, 2. The numerical control device according to claim 1, wherein, when the chip breakage signal is detected, the servo status information is used to calculate a corrected number of rotations of the spindle, which is calculated by going back a visual stimulus reaction time, which is the time from when the operator confirms the chip breakage to when the chip breakage signal is sent, to the number of rotations of the spindle at the time when the chip breakage signal was detected, and the vibration condition corresponding to the corrected number of rotations of the spindle is acquired.

7. a servo data acquisition unit that acquires the servo information at a predetermined cycle; the servo information further includes servo data that is information that can determine whether or not the tool is in contact with the workpiece during a unit operation period of the spindle, The vibration condition determination unit changing the vibration condition after recording the first servo data and the second servo data, which are the servo data in two consecutive unit operation periods while the operation of the spindle is stable, in the servo status information; 7. The numerical control device according to claim 6, wherein, when the chip breakage signal is detected, if it is determined using the first servo data and the second servo data that there is no missed section of the vibration cutting, alarm information is generated to indicate that chip breakage has not occurred.

8. 5. The numerical control device according to claim 4, wherein the servo data is feedback position data, which is a position detected by a detector attached to the servo motor, or feedback current data, which is a current value detected by a servo control unit that controls the servo motor.

9. 2. The numerical control device according to claim 1, wherein the vibration condition is an amplitude-feed ratio, which is a ratio between an amplitude of vibration and a movement amount of a tool for machining the workpiece relative to the workpiece per vibration.

10. The numerical control device according to any one of claims 1 to 9 and an information processing device having a communication unit are connected via a communication system, the numerical control device includes a communication unit that communicates with the information processing device, The numerical control system is characterized in that the information processing device is capable of transmitting the chip breaking signal to the numerical control device in response to an operation by the operator.

11. A numerical control method for a numerical control device that causes a machine tool to perform vibration cutting, comprising: an operator instruction detection step in which the numerical control device detects a chip breakage signal input by an operator observing the workpiece during vibration cutting, the chip breakage signal notifying the occurrence of chip breakage; a vibration condition determination step in which, when the numerical control device detects the chip breakage signal, the numerical control device indicates the relationship between vibration conditions, which are conditions for performing vibration cutting by the machine tool during vibration cutting, and servo information, which indicates the state of a servo motor that drives the machine tool, acquires servo state information recorded during the execution of vibration cutting, and determines the vibration conditions during vibration cutting based on the servo state information; A numerical control method comprising:

Images