Control device for machine tool

Abstract

Provided is a technique with which it is possible to calculate a chip length and to easily set a machining condition and a swing condition while confirming the calculated chip length. A control device (1) for a machine tool that performs machining while swinging a cutting tool and a workpiece relative to each other is provided with: a condition acquisition unit (12) that acquires a machining condition and a swinging condition; a chip length calculation unit (13) that calculates a chip length on the basis of the machining condition and the oscillation condition acquired by the condition acquisition unit (12); and a chip length output unit (14) that outputs the chip length calculated by the chip length calculation unit (13).

Description

Technical Field

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

[0002] Conventionally, in order to prevent chips continuously generated during cutting from entanglement with a workpiece or a cutting tool, which may cause machining defects or mechanical failures, swing cutting is known, in which a cutting tool and a workpiece are swung relative to each other while cutting the workpiece. In this swing cutting, the tool path, which is the trajectory of the cutting tool, is set to overlap a portion of the previous tool path by adjusting the swing frequency and the swing amplitude. Thus, the chips are broken up by generating a swing called a blank cut in which the cutting tool tip is separated from the surface of the workpiece.

[0003] Yet, even if can chip be broken up, if chip length is too long, then also there is the situation that chip is wrapped around workpiece or cutting tool.In addition, if excessively make cutting tool, workpiece swing in order to make chip length shorten, then mechanical load becomes large, and machinery is likely to break down.

[0004] For example, as a technology that takes chip length into consideration, a technology that determines the number of vibrations (oscillations) based on a set chip length and a workpiece diameter has been proposed (for example, see Patent Document 1). According to this technology, the number of vibrations can be automatically determined based on a set desired chip length and a workpiece diameter.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6744815 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, in the technology of Patent Document 1, the desired chip length is simply obtained based on the number of vibrations, but the chip length depends on the machining conditions and the swing conditions, and it is difficult to set the machining conditions and the swing conditions while considering the chip length. Therefore, a technology that can calculate the chip length and easily set the machining conditions and the swing conditions while confirming the calculated chip length is desired.

[0010] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a technology capable of calculating chip length and easily setting machining conditions and swing conditions while confirming the calculated chip length.

[0011] Means for solving problems

[0012] The present invention discloses a control device for a machine tool that performs processing while causing a cutting tool and a workpiece to swing relative to each other, the control device comprising: a condition acquisition unit that acquires processing conditions and swing conditions; a chip length calculation unit that calculates the chip length based on the processing conditions and the swing conditions acquired by the condition acquisition unit; and a chip length output unit that outputs the chip length calculated by the chip length calculation unit.

[0013] Effects of the Invention

[0014] According to the present disclosure, it is possible to provide a technology that can calculate the chip length and easily set the machining conditions and the swing conditions while checking the calculated chip length. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a diagram for explaining swing cutting.

[0016] Figure 2 This is a functional block diagram of the control device for the machine tool according to the first embodiment.

[0017] Figure 3 This figure shows the chip length confirmation screen after the machining conditions and swing conditions are input.

[0018] Figure 4 It is a diagram showing the cutting path.

[0019] Figure 5 It is a figure which shows the chip length confirmation screen which displays the calculated chip length.

[0020] Figure 6 This is a functional block diagram of a control device for a machine tool according to a second embodiment.

[0021] Figure 7 It is a diagram showing a first example of the chip length correction table.

[0022] Figure 8 It is a diagram showing a first example of the chip length correction table.

[0023] Fig. 9 It is a figure which shows the chip length confirmation screen which displays the calculated chip length.

[0024] Fig.10 The figure shows the chip length confirmation screen which displays the chip length corrected based on the correction coefficient of the chip length.

[0025] Fig.11 It is a diagram showing a second example of the chip length correction table.

[0026] Fig.12 It is a diagram showing a second example of the chip length correction table.

[0027] Fig.13 It is a figure which shows the chip length confirmation screen which displays the calculated chip length.

[0028] Fig.14 The figure shows a chip length confirmation screen which displays the chip length corrected for each type of workpiece.

[0029] Fig.15 This is a functional block diagram of a control device for a machine tool according to a third embodiment.

[0030] Fig.16 This is a graph showing the attenuation rate of the actual measured value of the swing amplitude with respect to the command value of the swing amplitude.

[0031] Fig.17 This is a diagram showing a chip length confirmation screen in which the attenuation rate of the vibration amplitude is input.

[0032] Fig.18 It is a diagram showing a chip length confirmation screen displaying the chip length corrected based on the attenuation rate of the swing amplitude. DETAILED DESCRIPTION

[0033] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the second embodiment and thereafter, the same reference numerals are given to the same configurations as those of the first embodiment, and the description thereof will be omitted as appropriate.

[0034] [First embodiment]

[0035] The control device for a machine tool according to the first embodiment executes swing cutting for cutting a workpiece while swinging a cutting tool and the workpiece relative to each other. Figure 1 This is a diagram for explaining swing cutting. Figure 1 In the example of swing cutting shown, at least one spindle S and at least one feed axis (not shown) are operated to rotate the cutting tool T and the workpiece W relative to each other, and the cutting tool T and the workpiece W are swung relative to each other in the feed direction while cutting. At least one spindle S rotates the cutting tool T and the workpiece W relative to each other, and at least one feed axis moves the cutting tool T relative to the workpiece W. At this time, the tool path as the trajectory of the cutting tool T is set so that the current path and the previous path partially overlap. That is, the current path partially includes the part that was processed in the previous path, thereby generating an idle swing called air cutting in which the cutting tip of the cutting tool T leaves the surface of the workpiece W, thereby crushing the chips.

[0036] In addition, in the swing cutting performed in the present embodiment, the shape of the workpiece is not limited. That is, even if the workpiece has a tapered portion or an arc portion on the machining surface and multiple feed axes (Z axis and X axis) are required, even if the workpiece is cylindrical or cylindrical and a specific feed axis (Z axis) is sufficient, it can also be applied.

[0037] Figure 2 1 is a functional block diagram of the control device 1 of the machine tool according to the first embodiment. Figure 2 As shown, the control device 1 of the machine tool of the first embodiment includes an input unit 11, a condition acquisition unit 12, a chip length calculation unit 13, a chip length output unit 14, and a chip length display unit 15. The control device 1 of the machine tool is configured using, for example, a computer including a memory such as a ROM (read only memory) and a RAM (random access memory) connected to each other via a bus, a CPU (control processing unit), and a communication control unit. The functions and actions of the above-mentioned functional units are realized by the cooperation of the CPU, the memory, and the control program stored in the memory mounted on the above-mentioned computer.

[0038] The control device 1 of the machine tool may be composed of a CNC (Computer Numerical Controller), and may also be connected to a host computer (not shown) such as a CNC or a PLC (Programmable Logic Controller). In addition to the machining program, machining conditions such as rotation speed and feed speed, and swing conditions such as swing amplitude and swing frequency are input from the host computer to the control device 1 of the machine tool.

[0039] The input unit 11 inputs information related to machining conditions and swing conditions according to an operator's input operation on an input unit (not shown) such as a keyboard or a touch panel. The information related to machining conditions and swing conditions input by the input unit 11 is output to a condition acquisition unit 12 described later.

[0040] The condition acquisition unit 12 acquires the machining conditions and the swing conditions inputted through the input unit 11. The condition acquisition unit 12 outputs the acquired machining conditions and the swing conditions to the chip length calculation unit 13 described later.

[0041] Here, as processing conditions, in addition to at least information related to the processing diameter (mm), it also includes information related to the spindle rotation speed S (1 / min), the feed amount per rotation F (mm / rev), the feed speed of the cutting tool (mm / min), the workpiece diameter (mm), the R of the tool tip (mm), the back angle of the cutting tool (°), etc.

[0042] In addition, as the swing condition, information related to the number of swings per rotation of the cutting tool and the workpiece relative to each other, and information about the swing amplitude relative to the feed amount per rotation of the cutting tool and the workpiece relative to each other are included. As information related to the number of swings per rotation of the cutting tool and the workpiece relative to each other, a swing frequency magnification I (times) indicating the swing frequency per rotation of the spindle can be cited. In addition, as information about the swing amplitude relative to the feed amount per rotation of the cutting tool and the workpiece relative to each other, a swing amplitude magnification K (times) indicating the size of the swing amplitude relative to the size of the feed amount per rotation of the spindle can be cited. The swing frequency magnification I (times) can be specified directly, or it can be calculated based on the swing frequency (Hz) and the spindle speed S (1 / min) after specifying the swing frequency (Hz). In addition, the swing amplitude magnification K (times) can also be specified directly, or it can be calculated based on the swing amplitude (mm) and the feed amount F (mm / rev) per rotation after specifying the swing amplitude (mm).

[0043] The chip length calculation unit 13 calculates the chip length based on the machining conditions and the swing conditions acquired by the condition acquisition unit 12. A specific method of calculating the chip length will be described in detail later.

[0044] The chip length output unit 14 outputs to the outside the chip length calculated by the chip length calculation unit 13. In the present embodiment, the chip length output unit 14 outputs the calculated chip length to a chip length display unit 15 described later.

[0045] The chip length display unit 15 displays the chip length output by the chip length output unit 14. Specifically, the chip length display unit 15 displays the chip length calculated by the chip length calculation unit 13 on a chip length confirmation screen described in detail later.

[0046] Next, refer to Figure 3 to Figure 5 The calculation method of the chip length by the chip length calculation unit 13 will be described in detail. Figure 3 It is a figure which shows the chip length confirmation screen in which the machining conditions and the swing conditions are input. Figure 4 It is a diagram showing the cutting path. Figure 5 It is a figure which shows the chip length confirmation screen which displays the calculated chip length.

[0047] like Figure 3As shown, first, the operator uses the chip length confirmation screen displayed by the chip length display unit 15 to input the machining conditions and the swing conditions by operating the input unit 11. Figure 3 As in the example shown, the operator inputs information on the machining diameter, namely, coordinate values ​​in the radial direction of the workpiece (also referred to as coordinate values ​​X) as machining conditions, and inputs a swing frequency magnification I and a swing amplitude magnification K as swing conditions.

[0048] In this way, the input machining conditions and swing conditions are obtained by the condition acquisition unit 12, and the chip length calculation unit 13 automatically calculates the chip length based on the obtained machining conditions and swing conditions. Specifically, the chip length calculation unit 13 uses the following formula (1) to calculate the coordinate value Y (mm) of the feed direction of the cutting path, and searches for the position where the phase difference between the intersection points of the cutting paths (the previous cutting path and the current cutting path) is the largest.

[0049] [Formula 1]

[0050]

[0051] In formula (1), Y represents the coordinate value of the feed direction (mm), f represents the feed amount per spindle rotation (mm / rev), S represents the spindle speed (1 / min), I represents the swing frequency multiplier (times), K represents the swing amplitude multiplier (times), and t represents time (sec).

[0052] Here, if Figure 4 As shown, the intersection of the last cutting path and the current cutting path is the starting point or the ending point of the air cutting. That is, the part with the largest phase difference between the intersection of the last cutting path and the current cutting path refers to the cutting interval of the maximum chip length with the largest chip length. Therefore, in this embodiment, the phase difference of the maximum chip length cutting interval is calculated by the above formula (1), and the maximum chip length obtained by multiplying the phase difference of the maximum chip length cutting interval by the workpiece radius (mm) is calculated as the chip length (mm) as shown in the following formula (2). Hereinafter, in this specification, the maximum chip length and the chip length are assumed to have the same meaning for explanation.

[0053] [Formula 2]

[0054] Chip length = (Phase difference in the maximum chip length cutting section (°) / 360 (°)) × workpiece radius × 2π (Formula 2)

[0055] It can be seen from the above-mentioned chip length calculation method that in the chip length calculated by the chip length calculation unit 13 of the present embodiment, the interval where air cutting occurs is removed, and the interval where air cutting occurs is not included in the chip length. In contrast, in the calculation of the chip length known in the past, when the workpiece radius (mm) is set to r and the swing frequency multiplier (times) is set to I, the chip length (mm) is calculated by 2πr / I, and the interval where air cutting occurs is also included in the chip length. Therefore, according to the chip length calculation unit 13 of the present embodiment, a more accurate chip length can be calculated compared with the past.

[0056] In addition, the chip length calculated by the chip length calculation unit 13 as described above is as follows: Figure 5 The chip length confirmation screen is automatically displayed as shown. As a result, the operator can set the machining conditions and swing conditions while confirming the chip length calculated more accurately than before, making it easier to set the machining conditions and swing conditions.

[0057] According to the control device 1 for a machine tool according to the first embodiment, the following effects are achieved.

[0058] The control device 1 of the machine tool of the present embodiment is provided with: a condition acquisition unit 12, which acquires machining conditions and swing conditions; a chip length calculation unit 13, which calculates the chip length based on the machining conditions and swing conditions; and a chip length output unit 14, which outputs the calculated chip length. Thus, the chip length depends on the machining conditions and swing conditions, and it was difficult to set the machining conditions and swing conditions while considering the chip length in the past. According to the present embodiment, the chip length can be calculated based on the machining conditions and swing conditions, and the machining conditions and swing conditions can be easily set while confirming the chip length calculated and output to the outside.

[0059] In addition, the control device 1 of the machine tool of the present embodiment is further provided with a chip length display unit 15, which displays the chip length output by the chip length output unit 14. Thus, the operator can more easily set the machining conditions and the swing conditions while checking the chip length displayed on the display screen of the chip length display unit 15.

[0060] In addition, the control device 1 of the machine tool of the present embodiment is configured to obtain information related to the machining diameter as a machining condition, and to obtain information related to the number of swings per one rotation of the cutting tool and the workpiece relative to each other, and information on the swing amplitude relative to the feed amount per one rotation of the cutting tool and the workpiece relative to each other as a swing condition, and calculate the chip length based on these machining conditions and swing conditions. Thus, although the chip length depends on the swing amplitude that has a great influence on the occurrence of air cutting, the swing amplitude has not been considered in the past. According to the present embodiment, the swing amplitude can also be included in the calculation conditions to calculate the chip length, and a more accurate chip length can be calculated without the air cutting generation interval.

[0061] [Second Embodiment]

[0062] Figure 6 1A is a functional block diagram of a control device 1A for a machine tool according to a second embodiment. Figure 6 As shown, the control device 1A of the machine tool of the second embodiment is different from the control device 1 of the machine tool of the first embodiment in that it also includes a correction value calculation unit 16 and an actual chip length acquisition unit 17, and unlike the chip length calculation unit 13 of the first embodiment, the chip length calculation unit 13A also corrects the chip length. The other structures are the same as those of the first embodiment.

[0063] The actual chip length acquisition unit 17 acquires the actual chip length obtained by actually measuring the chip length obtained by actually performing the swing cutting process, and outputs the acquired actual chip length to the correction value calculation unit 16 described later.

[0064] The correction value calculation unit 16 calculates a correction value for correcting the chip length. Specifically, the correction value calculation unit 16 calculates the correction value based on the theoretical chip length calculated by the chip length calculation unit 13A and the actual chip length measured by the actual chip length acquisition unit 17. For example, the correction value calculation unit 16 calculates a correction coefficient or a correction amount based on the deviation ratio or difference between the actual chip length obtained by actually performing the swing cutting process under the machining conditions used in the calculation and the swing conditions and the theoretical chip length. The calculated correction value is output to the chip length calculation unit 13A described later.

[0065] In addition, it is preferred that the correction value calculation unit 16 calculates the correction value for each machining condition. Specifically, it is preferred that the correction value calculation unit 16 calculates the correction value for each machining condition including at least one of the material of the cutting edge of the cutting tool, the shape of the cutting edge of the cutting tool, the material of the workpiece, the cutting speed, the cutting thickness, and the cutting angle.

[0066] The chip length calculation unit 13A calculates the chip length based on the machining conditions and the swing conditions acquired by the condition acquisition unit 12 by the same calculation method as the chip length calculation unit 13 of the first embodiment. In addition, the chip length calculation unit 13A, unlike the chip length calculation unit 13 of the first embodiment, uses the correction value calculated by the correction value calculation unit 16 to correct the calculated theoretical chip length.

[0067] Next, refer to Figure 7 to Figure 10 A first example of a method of correcting the chip length by the chip length calculation unit 13A will be described in detail. Figure 7 and Figure 8 It is a diagram showing a first example of the chip length correction table. Fig. 9 It is a figure which shows the chip length confirmation screen which displays the calculated chip length. Fig.10 The figure shows a chip length confirmation screen showing the chip length corrected based on the correction coefficient of the chip length.

[0068] First, similarly to the first embodiment described above, the operator inputs information related to the machining diameter, that is, the coordinate value X in the radial direction of the workpiece as a machining condition, and inputs the oscillation frequency magnification I and the oscillation amplitude magnification K as oscillation conditions. Fig. 9 As shown, the theoretical chip length automatically calculated by the chip length calculation unit 13A is displayed as the chip length on the chip length confirmation screen. In addition, the operator operates the control device 1A of the machine tool before and after the above-mentioned input operation, actually performs the swing cutting process under the processing conditions and swing conditions for calculating the theoretical chip length, and actually measures the length of the obtained chip.

[0069] Next, the operator operates the input unit of the input unit 11 to open the Figure 7 The chip length correction table is shown in Figure 1. Figure 7 As shown, in the chip length correction table, in addition to the coordinate value X in the radial direction of the workpiece, the swing frequency magnification I, and the swing amplitude magnification K entered in the chip length confirmation screen, the calculated theoretical chip length is automatically displayed.

[0070] Therefore, the operator operates the input unit of the input unit 11 to input the actual chip length obtained by actual measurement. Then, the correction value calculation unit 16 automatically calculates the correction coefficient based on, for example, the deviation ratio between the theoretical chip length and the actual chip length, and automatically displays the calculated correction coefficient in the chip length correction table. Fig.10 As shown, the display of the chip length on the chip length confirmation screen is changed to the value of the chip length corrected using the correction coefficient.

[0071] In addition, if Figure 7 and Figure 8As shown in FIG. 1 , when there are multiple combinations of input machining conditions and swing conditions, and there are multiple combinations of theoretical chip length and actual chip length according to the combinations of the conditions, it is preferred that the correction value calculation unit 16 automatically calculates the correction coefficient according to the arithmetic mean of the deviation magnifications of the theoretical chip length and the actual chip length calculated in each combination. When deriving the correction coefficient according to the deviation magnification, other data analysis methods such as geometric mean, harmonic mean, median value, and mode value may also be used.

[0072] Next, refer to Figure 11 to Figure 14 A second example of the method of correcting the chip length by the chip length calculation unit 13A will be described in detail. Fig.11 and Fig.12 It is a diagram showing a second example of the chip length correction table. Fig.13 It is a figure which shows the chip length confirmation screen which displays the calculated chip length. Fig.14 The figure shows a chip length confirmation screen which displays the chip length corrected for each type of workpiece.

[0073] First, the operator inputs information related to the machining diameter, namely, the radial coordinate value X of the workpiece and the type (material) of the workpiece as machining conditions, and inputs the oscillation frequency magnification I and the oscillation amplitude magnification K as oscillation conditions. Fig.13 As shown, the theoretical chip length automatically calculated by the chip length calculation unit 13A is displayed as the chip length on the chip length confirmation screen in accordance with the type of the selected workpiece. In addition, the operator operates the control device 1A of the machine tool before and after the above-mentioned input operation, actually performs the swing cutting process under the processing conditions and swing conditions for calculating the theoretical chip length, and actually measures the length of the obtained chip.

[0074] Next, the operator operates the input unit of the input unit 11 to open the Fig.11 The chip length correction table is shown in Figure 1. Fig.11 As shown, in the chip length correction table, in addition to the workpiece radial coordinate value X, workpiece type, swing frequency magnification I, and swing amplitude magnification K entered in the chip length confirmation screen, the calculated theoretical chip length is also automatically displayed.

[0075] Therefore, the operator operates the input unit of the input unit 11 to input the actual chip length obtained by actual measurement. Then, the correction value calculation unit 16 automatically calculates the correction coefficient based on, for example, the deviation ratio between the theoretical chip length and the actual chip length, and the calculated correction coefficient is automatically displayed in the chip length correction table. Fig.14 As shown, the display of the chip length on the chip length confirmation screen is changed to the value of the chip length corrected using the correction coefficient.

[0076] In addition, if Fig.11 and Fig.12 As shown, a correction coefficient is calculated for each type of workpiece. In this second example, an example of calculating a correction coefficient for each type of workpiece is given, but correction values ​​such as correction coefficients can be calculated not only for the type of workpiece, but also for each processing condition including at least one of the material of the cutting tool tip, the shape of the cutting tool tip, the cutting speed, the cutting thickness, and the cutting angle. In addition, similarly to the first example, when there are multiple combinations of input processing conditions and swing conditions, and there are multiple combinations of theoretical chip lengths and actual chip lengths according to the combinations of the conditions, it is preferred that the correction value calculation unit 16 automatically calculates the correction coefficient based on the average value of the deviation magnification of the theoretical chip length and the actual chip length calculated in each combination.

[0077] According to the control device 1A for a machine tool according to the second embodiment, the following effects are achieved.

[0078] In the control device 1A of the machine tool of the second embodiment, a correction value calculation unit 16 is further provided, which calculates a correction value for correcting the chip length, and the calculated chip length is corrected using the correction value calculated by the correction value calculation unit 16. More specifically, an actual chip length acquisition unit 17 is further provided, which acquires the actual chip length obtained by actually performing the machining, and calculates the correction value based on the calculated theoretical chip length and the actual chip length. Thus, a more accurate chip length can be calculated.

[0079] In the control device 1A of the machine tool of the second embodiment, the correction value calculation unit 16 is configured to calculate the correction value for each machining condition. More specifically, the correction value calculation unit 16 is configured to calculate the correction value for each machining condition including at least one of the material of the cutting edge of the cutting tool, the shape of the cutting edge of the cutting tool, the material of the workpiece, the cutting speed, the cutting thickness, and the cutting angle. Thus, a more accurate chip length can be calculated.

[0080] [Third Embodiment]

[0081] Fig.15 1B is a functional block diagram of a machine tool control device according to the third embodiment. Fig.15 As shown, the control device 1B of the machine tool of the third embodiment is different from the control device 1 of the machine tool of the first embodiment in that it also has a correction value calculation unit 16A and an actual swing amplitude acquisition unit 18, and unlike the chip length calculation unit 13 of the first embodiment, the chip length calculation unit 13B also performs chip length correction. The other structures are the same as those of the first embodiment.

[0082] The actual swing amplitude acquisition unit 18 acquires the swing amplitude of the cutting path measured by actually performing the swing cutting process under the machining conditions and swing conditions for calculating the theoretical chip length as the actual swing amplitude. The measured value of the cutting path can be acquired by a position detector such as an encoder generally provided in the servo motor. The acquired actual swing amplitude is output to the correction value calculation unit 16A described later.

[0083] The correction value calculation unit 16A calculates a correction value for correcting the chip length. Specifically, the correction value calculation unit 16A calculates the correction value based on the attenuation rate of the actual swing amplitude obtained by the actual swing amplitude acquisition unit 18 relative to the swing amplitude obtained by the condition acquisition unit 12, that is, the swing amplitude command value. For example, the attenuation rate itself is used as the correction value. The calculated correction value is output to the chip length calculation unit 13B described later.

[0084] In addition, it is preferred that the correction value calculation unit 16A calculates the correction value for each processing condition, specifically, for each processing condition including at least any one of the material of the cutting tool tip, the shape of the cutting tool tip, the material of the workpiece, the cutting speed, the cutting thickness and the cutting angle, in the same manner as the correction value calculation unit 16 of the second embodiment.

[0085] The chip length calculation unit 13B calculates the theoretical chip length based on the machining conditions and the swing conditions acquired by the condition acquisition unit 12 by the same calculation method as the chip length calculation unit 13 of the first embodiment. In addition, the chip length calculation unit 13B calculates the chip length by substituting the value obtained by multiplying the swing amplitude magnification K by the attenuation rate as a correction value into the formula (1) instead of the swing amplitude magnification K by the same calculation method as the chip length calculation unit 13 of the first embodiment when using the above-mentioned formula (1) to calculate the chip length. In this way, the chip length corrected based on the attenuation rate can be calculated.

[0086] Next, refer to Figure 16 to Figure 18 The method of correcting the chip length by the chip length calculation unit 13B will be described in detail. Fig.16 This is a graph showing the attenuation rate of the actual measurement value with respect to the command value of the swing amplitude. Fig.17 This is a diagram showing a chip length confirmation screen in which the attenuation rate of the vibration amplitude is input. Fig.18 It is a diagram showing a chip length confirmation screen displaying the chip length corrected based on the attenuation rate of the vibration amplitude.

[0087] First, similarly to the first embodiment, the operator inputs information related to the machining diameter, that is, the coordinate value X in the radial direction of the workpiece as machining conditions, and inputs the oscillation frequency magnification I and the oscillation amplitude magnification K as oscillation conditions. Fig.17As shown, the theoretical chip length automatically calculated by the chip length calculation unit 13B is displayed as the chip length on the chip length confirmation screen. In addition, the operator operates the control device 1A of the machine tool before and after the above-mentioned input operation, and actually performs the swing cutting process under the processing conditions and swing conditions for calculating the theoretical chip length, and obtains the actual measurement value of the cutting path.

[0088] Then, if Fig.16 As shown in FIG. 1 , the correction value calculation unit 16A calculates the attenuation rate of the actual value relative to the command value of the swing amplitude by comparing the command value of the cutting path with the actual value, and uses the calculated attenuation rate itself as the correction value. Then, the chip length calculation unit 13B calculates the chip length corrected based on the attenuation rate, as shown in FIG. Fig.18 As shown, the attenuation rate of the amplitude is displayed on the chip length confirmation screen, and the display of the chip length is changed to the value of the chip length corrected based on the attenuation rate.

[0089] According to the control device 1B for a machine tool according to the third embodiment, the following effects are achieved.

[0090] In the control device 1B of the machine tool of the third embodiment, an actual swing amplitude acquisition unit 18 is further provided, which acquires an actual swing amplitude obtained by actually performing swing cutting processing, and the correction value calculation unit 16A is configured to calculate the correction value based on the attenuation rate of the actual swing amplitude acquired by the actual swing amplitude acquisition unit 18 with respect to the swing amplitude acquired by the condition acquisition unit 12. In this way, a more accurate chip length can be calculated.

[0091] In addition, the present disclosure is not limited to the above-mentioned embodiment, and modifications and improvements within the scope that can achieve the purpose of the present disclosure are also included in the present disclosure.

[0092] For example, in the second and third embodiments, the correction value is automatically calculated by the correction value calculation unit 16, 16A, but the present invention is not limited thereto and the operator may manually input and set the correction value calculated by an external computer.

[0093] For example, in the third embodiment described above, if the attenuation rate of the actual vibration amplitude is known from the result of the frequency response of the machine, the correction value may be calculated based on the attenuation rate.

[0094] Description of Reference Numerals

[0095] 1. Control device of 1A and 1B machine tools

[0096] 11 Input section

[0097] 12 Condition Acquisition Department

[0098] 13, 13A, 13B Chip length calculation section

[0099] 14 Chip length output

[0100] 15 Chip length display

[0101] 16.16A correction value calculation unit

[0102] 17 Actual chip length acquisition unit

[0103] 18: Actual swing amplitude acquisition unit.

Claims

1. A control device for a machine tool, wherein the machine tool performs machining while causing a cutting tool and a workpiece to swing relative to each other, characterized in that: The control device has: a condition acquisition unit that acquires processing conditions and swing conditions; a chip length calculation unit that calculates a chip length based on the machining condition and the swing condition acquired by the condition acquisition unit; and A chip length output unit outputs the chip length calculated by the chip length calculation unit.

2. The control device for a machine tool according to claim 1, characterized in that: The control device further includes a chip length display unit that displays the chip length output by the chip length output unit.

3. The control device for a machine tool according to claim 1 or 2, characterized in that: The condition acquisition unit acquires information related to the machining diameter as the machining condition, and acquires information related to the number of swings per relative rotation of the cutting tool and the workpiece and information on the swing amplitude relative to the feed amount per relative rotation of the cutting tool and the workpiece as the swing condition.

4. The control device for a machine tool according to any one of claims 1 to 3, characterized in that: The control device further includes a correction value calculation unit that calculates a correction value for correcting the chip length. The chip length calculation unit corrects the chip length calculated based on the machining condition and the swing condition acquired by the condition acquisition unit, using the correction value calculated by the correction value calculation unit.

5. The control device for a machine tool according to claim 4, characterized in that: The control device further includes an actual chip length acquisition unit that acquires an actual chip length obtained by actually executing the machining. The correction value calculation unit calculates the correction value based on the chip length calculated by the chip length calculation unit and the actual chip length acquired by the actual chip length acquisition unit.

6. The control device for a machine tool according to claim 4, characterized in that: The correction value calculation unit calculates the correction value based on a decay rate of an actual swing amplitude with respect to a swing amplitude.

7. The control device for a machine tool according to claim 6, characterized in that: The control device further includes an actual swing amplitude acquisition unit that acquires an actual swing amplitude obtained by actually executing the machining. The condition acquisition unit acquires the swing amplitude, An attenuation rate of an actual swing amplitude with respect to the swing amplitude is calculated based on the swing amplitude acquired by the condition acquisition unit and the actual swing amplitude acquired by the actual swing amplitude acquisition unit.

8. The control device for a machine tool according to any one of claims 4 to 7, characterized in that: The correction value calculation unit calculates the correction value for each of the machining conditions.

9. The control device for a machine tool according to claim 8, characterized in that: The correction value calculation unit calculates the correction value for each of the machining conditions including at least one of the material of the cutting edge of the cutting tool, the shape of the cutting edge of the cutting tool, the material of the workpiece, the cutting speed, the cutting thickness, and the cutting angle.

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