Control unit for machine tool

Abstract

A technology is provided for calculating a chip length and for easily setting a machining state and an oscillation state while verifying the calculated chip length. A control unit 1 of a machine tool that performs machining while causing a cutting tool and a workpiece to oscillate relative to each other comprises: a state detection unit 12 for detecting a machining state and an oscillation state; a chip length calculation unit 13 for calculating a chip length based on the machining state and the oscillation state detected by the state detection unit 12; and a chip length output unit 14 for outputting the chip length calculated by the chip length calculation unit 13.

Description

Technical area

[0001] The present disclosure relates to a control device for machine tools. State of the art

[0002] Oscillation cutting is conventionally known as cutting a workpiece while oscillating a cutting tool and the workpiece relative to each other to prevent chips continuously generated during cutting from becoming entangled with the workpiece or cutting tool, which may cause defects or machine failure. In oscillation cutting, the oscillation frequency and amplitude are adjusted, and the tool path is selected to partially overlap the previous tool path. This creates an air cut in which the cutting edge of the cutting tool moves away from the surface of the workpiece, thereby crushing the chips.

[0003] However, even if the chips are reduced in size, if the chip length is too long, they can still become entangled with the workpiece or cutting tool. Excessive oscillation of the cutting tool or workpiece to shorten the chip length can increase machine stress and potentially lead to machine failure.

[0004] For example, a technique that considers the chip length to determine the number of oscillations based on the set chip length and the workpiece diameter has been proposed (see, for example, Patent Document 1). With this method, the number of oscillations can be automatically determined based on the set desired chip length and the set workpiece diameter. Citation listPatent document

[0005] Patent Document 1: Japanese Patent No. 6744815 Disclosure of the invention Problems to be solved by the invention

[0006] However, the technique disclosed in Patent Document 1 simply determines the desired chip length from the number of oscillations. However, since the chip length depends on the machining conditions and oscillation conditions, it has been difficult to specify the machining conditions and oscillation conditions while considering the chip length. Therefore, a technique that can calculate the chip length and easily adjust the machining conditions and oscillation conditions while checking the calculated chip length is desired.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and an object thereof is to provide a technique capable of calculating the chip length and easily adjusting the machining conditions and oscillation conditions while checking the calculated chip length. Means to solve the problems

[0008] The present disclosure provides a control device for a machine tool that machines a workpiece while the cutting tool and the workpiece are relatively oscillating. The control device includes: a state detection unit that detects machining states and oscillation states; a chip length calculation unit that calculates a chip length based on the machining states and oscillation states detected by the state detection unit; and a chip length output unit that outputs the chip length calculated by the chip length calculation unit. Effects of the invention

[0009] According to the present disclosure, it is possible to provide a technique capable of calculating a chip length and easily setting machining conditions and oscillation conditions while checking the calculated chip length. Brief description of the drawings Fig. Figure 1 is a diagram illustrating oscillation cutting; Fig. 2 is a functional block diagram of a machine tool control apparatus according to the first embodiment; Fig. 3 is a diagram showing a chip length confirmation screen in which the machining conditions and oscillation conditions have been input; Fig. 4 is a diagram showing a cutting path; Fig. 5 is a diagram showing a chip length confirmation screen displaying the calculated chip length; Fig. 6 is a functional block diagram of a machine tool control apparatus according to the second embodiment; Fig. 7 is a diagram showing the first example of a chip length correction table; Fig. 8 is a diagram showing the first example of the chip length correction table; Fig. 9 is a diagram showing a screen for confirming the calculated chip length; Fig. 10 is a diagram showing a chip length confirmation screen that displays the chip length corrected based on the chip length correction coefficient; Fig. 11 is a diagram showing the second example of the chip length correction table; Fig. 12 is a diagram showing the second example of the chip length correction table; Fig. 13 is a diagram showing a chip length confirmation screen displaying the calculated chip length; Fig. 14 is a diagram showing a chip length confirmation screen indicating the chip length corrected for each workpiece type; Fig. 15 is a functional block diagram of a machine tool control apparatus according to the third embodiment; Fig. Figure 16 is a graph showing the damping rate of the actual measured value versus the target value of the oscillation amplitude; Fig. 17 is a diagram showing a chip length confirmation screen on which the oscillation amplitude damping rate has been entered; and Fig. 18 is a diagram showing a chip length confirmation screen that displays the chip length corrected based on the damping rate of the oscillation amplitude. Preferred embodiment of the invention

[0010] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. In the descriptions of the second and subsequent embodiments, the components common to the first embodiment are denoted by the same reference numerals, and their descriptions will be omitted where appropriate. [First embodiment]

[0011] The machine tool control apparatus according to the first embodiment performs oscillation cutting in which a workpiece is machined by cutting while the cutting tool and the workpiece oscillate relative to each other. Fig. 1 is a diagram illustrating oscillation cutting. In the Fig. In the example of oscillation cutting shown in Figure 1, at least one spindle S that relatively rotates the cutting tool T and the workpiece W, and at least one feed shaft (not shown) that moves the cutting tool T relative to the workpiece W are operated to relatively rotate the cutting tool T and the workpiece W, while the cutting tool T and the workpiece W oscillate in the feed direction during cutting. In this case, the tool route is set as the path of the cutting tool T so that the current route partially overlaps the previous route. Since the current route partially encloses the machined part of the previous route, air cutting occurs in which the cutting edge of the cutting tool T moves away from the surface of the workpiece W, thereby crushing the chips.

[0012] In the oscillation cutting performed in the present embodiment, the shape of the workpiece is not limited. That is, the present embodiment can be applied in cases where multiple feed shafts (Z-axis and X-axis) are required because the workpiece has tapered or arcuate sections on the machining surface, or in cases where a specific feed shaft (Z-axis) is sufficient because the workpiece is columnar or cylindrical.

[0013] Fig. 2 is a functional block diagram of a machine tool control device 1 according to the first embodiment. As shown in Fig. As shown in Figure 2, the machine tool control device 1 according to the first embodiment includes an input unit 11, a state detection unit 12, a chip length calculation unit 13, a chip length output unit 14, and a chip length display unit 15. The machine tool control device 1 is composed of a computer including memories such as ROM (Read Only Memory) and RAM (Random Access Memory), a CPU (Control Processing Unit), and a communication control unit, which are connected to each other via a bus. The functions and operations of each functional unit are achieved through the cooperation of the CPU, the memory, and the control programs stored in the memory in the computer.

[0014] The machine tool control unit 1 can consist of a CNC (Computer Numerical Controller) and be connected to higher-level computers such as a CNC or a PLC (Programmable Logic Controller) (not shown). The higher-level computer transmits machining states such as rotational speed and feed rate, as well as oscillation states such as oscillation amplitude and oscillation frequency, to the machine tool control unit 1.

[0015] The input unit 11 inputs information about the machining and oscillation states in response to operator inputs using input means (not shown), such as a keyboard or touch panel. The information about the machining states and oscillation states input by the input unit 11 is output to the state acquisition unit 12, which will be described later.

[0016] The state detection unit 12 detects the machining states and oscillation states input from the input unit 11. The state detection unit 12 outputs the detected machining states and oscillation states to the chip length calculation unit 13, which will be described later.

[0017] The machining conditions include at least information on the machining diameter (mm) and, for example, information on the speed S (1 / min) of the spindle, the feed rate per revolution F (mm / rev), the feed rate of the cutting tool (mm / min), the workpiece diameter (mm), the radius (R) (mm) of the cutting edge and the clearance angle (°) of the cutting tool.

[0018] The oscillation states include information about the number of oscillations per relative revolution of the cutting tool and the workpiece, as well as information about the oscillation amplitude relative to the feed rate per relative revolution of the cutting tool and the workpiece. The information about the number of oscillations per relative revolution of the cutting tool and the workpiece includes an oscillation frequency multiplication factor I (times) that indicates the oscillation frequency per spindle revolution. The information about the oscillation amplitude relative to the feed rate per relative revolution of the cutting tool and the workpiece includes an oscillation amplitude multiplication factor K (times) that indicates the magnitude of the oscillation amplitude relative to the feed rate per spindle revolution.The oscillation frequency multiplication factor I (times) can be specified directly or calculated from the oscillation frequency (Hz) and the spindle speed S (rpm) after specifying the oscillation frequency (Hz). Similarly, the oscillation amplitude multiplication factor K (times) can be specified directly or calculated from the oscillation amplitude (mm) and the feed rate per revolution F (mm / rev) after specifying the oscillation amplitude (mm).

[0019] The chip length calculation unit 13 calculates the chip length based on the machining conditions and the oscillation conditions detected by the condition detection unit 12. The specific method for calculating the chip length will be described in detail later.

[0020] The chip length output unit 14 outputs the chip length calculated by the chip length calculation unit 13 to the outside. In the present embodiment, the chip length output unit 14 outputs the calculated chip length to the chip length display unit 15, which will be described later.

[0021] 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, which will be described in detail later.

[0022] The following describes the method for calculating the chip length by the chip length calculation unit 13 with reference to the Fig. 3 to 5 described in detail. Fig. Figure 3 is a diagram showing a chip length confirmation screen in which the machining conditions and oscillation conditions have been input. Fig. 4 is a diagram illustrating a cutting path. Fig. Figure 5 is a diagram showing a chip length confirmation screen that displays the calculated chip length.

[0023] As in Fig. 3, the operator first inputs the machining states and oscillation states by operating the input means of the input unit 11 using the chip length confirmation screen of the chip length display unit 15. As in the example in Fig. 3, for example, the operator inputs the machining conditions including the coordinate value in the direction of the workpiece diameter (also called the coordinate value X), which represents the information about the machining diameter, and the oscillation conditions including the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K.

[0024] Then, the state detection unit 12 acquires the input machining states and oscillation states, and the chip length calculation unit 13 automatically calculates the chip length based on the thus acquired machining states and oscillation states. Specifically, the chip length calculation unit 13 calculates the coordinate value Y (mm) in the feed direction of the cutting path using the following formula 1 and searches for the section with the maximum phase difference between the intersection points of the cutting paths (previous cutting path and current cutting path). Formula 1 Y=fS60t+Kf2{cos(2πSI60t)−1}

[0025] In formula 1, Y stands for the coordinate value in the feed direction (mm), f for the feed amount per revolution (mm / rev) of the spindle, S for the speed (1 / min) of the spindle, I for the multiplication factor of the oscillation frequency (times), K for the multiplication factor of the oscillation amplitude (times) and t for the time (sec).

[0026] In this case, as in Fig. 4, the intersection point of the previous and current cutting trajectories is the start or end point of an air cut. That is, the portion with the maximum phase difference between the intersection points of the previous and current cutting trajectories represents the cutting region where the chip length becomes maximum. Therefore, in the present embodiment, the phase difference in the cutting region for the maximum chip length is obtained by Formula 1, and the maximum chip length obtained by multiplying the phase difference in the cutting region for the maximum chip length by the workpiece radius (mm) is calculated as the chip length (mm) as in Formula 2. Hereinafter, in this description, the maximum chip length and the chip length are referred to as synonyms. Formula 2 Chip length = (phase difference (°) in the cutting area for maximum chip length / 360 (°)) × workpiece radius × 2π

[0027] As can be seen from the chip length calculation method described above, the chip length calculated by the chip length calculation unit 13 of the present embodiment excludes the air cutting portion. In contrast, the conventionally known chip length calculation includes the air cutting portion, in which the chip length is calculated as follows: chip length (mm) = 2πr / I, where r is the workpiece radius (mm) and I is the oscillation frequency multiplication factor (times). Therefore, the chip length calculation unit 13 of the present embodiment can calculate a more accurate chip length compared to the conventional method.

[0028] As in Fig. As shown in Figure 5, the chip length calculated by the chip length calculation unit 13 is automatically displayed on the chip length confirmation screen. This allows the operator to set the machining states and oscillation states while simultaneously checking the chip length, which is calculated more accurately than conventional methods, enabling easy setting of the machining states and oscillation states.

[0029] The machine tool control apparatus 1 according to the first embodiment can achieve the following effects.

[0030] The machine tool control device 1 according to the present embodiment includes the state detection unit 12 that detects machining states and oscillation states, the chip length calculation unit 13 that calculates the chip length based on the machining states and oscillation states, and the chip length output unit 14 that outputs the calculated chip length. While the chip length depends on the machining and oscillation states, and it was conventionally difficult to adjust the machining and oscillation states while considering the chip length, the present embodiment enables the calculation of the chip length based on the machining and oscillation states, allowing the operator to easily adjust the machining and oscillation states while checking the calculated and externally output chip length.

[0031] The machine tool control device 1 according to the present embodiment further includes the chip length display unit 15, which displays the chip length output by the chip length output unit 14. This allows the operator to more easily adjust the machining conditions and oscillation conditions while checking the chip length displayed on the screen of the chip length display unit 15.

[0032] The machine tool control device 1 according to the present embodiment acquires the machining conditions, including information on the machining diameter, and the oscillation conditions, including information on the number of oscillations per relative revolution of the cutting tool and the workpiece, as well as information on the oscillation amplitude relative to the feed rate per relative revolution of the cutting tool and the workpiece, and calculates the chip length based on the machining conditions and the oscillation conditions. Although the chip length depends on the oscillation amplitude, which significantly affects the occurrence of air cutting, conventional methods have not considered the oscillation amplitude. However, in the present embodiment, the oscillation amplitude is included in the calculation conditions, enabling more accurate calculation of the chip length without the air cutting range. [Second embodiment]

[0033] Fig. 6 is a functional block diagram of a machine tool control device 1A according to the second embodiment. As shown in Fig. As shown in Figure 6, the machine tool control device 1A according to the second embodiment further includes a correction value calculation unit 16 and an actual chip length detection unit 17, which are different from the machine tool control device 1 according to the first embodiment. Furthermore, the chip length calculation unit 13A also performs chip length correction, which is different from the chip length calculation unit 13 of the first embodiment. Other configurations are common to the first embodiment.

[0034] The actual chip length detection unit 17 detects the actual chip length by measuring the length of the chips obtained by actually performing the oscillating cutting. The detected actual chip length is output to the correction value calculation unit 16, which will be described later.

[0035] The correction value calculation unit 16 calculates the correction value used to correct 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 detected by the actual chip length detection unit 17. For example, the correction value calculation unit 16 calculates the correction coefficient or correction amount based on the deviation multiplication factor or the difference between the theoretical chip length and the actual chip length obtained by actually performing oscillation cutting under the machining conditions and oscillation conditions used for the calculation. The calculated correction value is output to the chip length calculation unit 13A, which will be described later.

[0036] The correction value calculation unit 16 preferably calculates correction values ​​for each machining state. Specifically, the correction value calculation unit 16 preferably calculates correction values ​​for each machining state, including at least one of the following: 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 depth, or the cutting angle.

[0037] The chip length calculation unit 13A calculates the chip length based on the machining conditions and oscillation conditions detected by the condition detection unit 12, using the same calculation method as used in the chip length calculation unit 13 of the first embodiment. The chip length calculation unit 13A corrects the calculated theoretical chip length using the correction value calculated by the correction value calculation unit 16, which is different from the chip length calculation unit 13 of the first embodiment.

[0038] Next, a first example of the chip length correction by the chip length calculation unit 13A will be described with reference to the Fig. 7 to 10 described in detail. Fig. 7 and Fig. 8 are diagrams showing the first example of the chip length correction table. Fig. Figure 9 is a diagram showing a chip length confirmation screen that displays the calculated chip length. Fig. 10 is a diagram showing a chip length confirmation screen that displays the chip length corrected based on the correction coefficient.

[0039] First, similar to the first embodiment described above, the operator inputs the machining conditions including the coordinate value X in the direction of the workpiece diameter, which contains information about the machining diameter, and the oscillation conditions including the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K. Then, as shown in Fig. As shown in Figure 9, 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. The operator operates the machine tool control unit 1A before and after the above input operation, actually performs oscillation cutting using the machining conditions and oscillation conditions used for calculating the theoretical chip length, and measures the length of the obtained chips.

[0040] The operator then operates the input means of the input unit 11 to Fig. 7 to open the chip length correction table and correct the calculated theoretical chip length. As in Fig. As shown in Figure 7, the chip length correction table automatically displays the coordinate value X in the workpiece diameter direction, the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K input on the chip length confirmation screen, and the calculated theoretical chip length.

[0041] The operator then operates the input means of the input unit 11 to enter the actually measured chip length. Based on the multiplication factor for the deviation between the theoretical chip length and the actual chip length, the correction value calculation unit 16 automatically calculates the correction coefficient. The calculated correction coefficient is automatically displayed in the chip length correction table. As shown in Fig. 10, the chip length displayed on the chip length confirmation screen is changed to the value of the chip length corrected with the correction coefficient.

[0042] As in the Fig. 7 and Fig. As shown in Figure 8, when multiple combinations of machining states and oscillation states are input and multiple combinations of theoretical chip lengths and actual chip lengths exist for each combination of states, the correction value calculation unit 16 preferably automatically calculates the correction coefficient based on the arithmetic mean of the deviation multiplication factors between the theoretical chip length calculated for each combination and the actual chip length. Other data analysis methods such as the geometric mean, harmonic mean, median, and mode value can also be used to derive the correction coefficient from the deviation multiplier.

[0043] Next, a second example of the chip length correction method by the chip length calculation unit 13A will be explained with reference to the Fig. 11 to 14 are described in detail. Fig. 11 and Fig. 12 are diagrams showing the second example of the chip length correction table. Fig. Figure 13 is a diagram showing a chip length confirmation screen that displays the calculated chip length. Fig. Figure 14 is a diagram showing a chip length confirmation screen that displays the chip length corrected for each workpiece type.

[0044] First, the operator inputs the machining conditions, including the coordinate value X in the direction of the workpiece diameter, which represents the information about the machining diameter, and the type (material) of the workpiece, as well as the oscillation conditions, including the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K. Then, as shown in Fig. As shown in Figure 13, 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 according to the selected workpiece type. The operator operates the machine tool control unit 1A before and after the above input operation, actually performs oscillation cutting machining using the machining conditions and oscillation conditions used for calculating the theoretical chip length, and measures the length of the resulting chips.

[0045] Next, the operator operates the input means of the input unit 11 to enter the Fig. 11 and correct the calculated theoretical chip length. Then the chip length correction table shows as shown in Fig. 11, automatically displays the coordinate value X in the direction of the workpiece diameter, the type of workpiece, the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K, which are input on the chip length confirmation screen, and the calculated theoretical chip length.

[0046] The operator then operates the input device of the input unit 11 to enter the actually measured chip length. Based on the multiplication factor for the deviation between the theoretical chip length and the actual chip length, the correction value calculation unit 16 automatically calculates the correction coefficient. The calculated correction coefficient is automatically displayed in the chip length correction table. As shown in Fig. 14, the chip length displayed on the chip length confirmation screen is changed to the value of the chip length corrected with the correction coefficient.

[0047] As in the Fig. 11 and Fig. As shown in Figure 12, the correction coefficient is calculated for each workpiece type. In the second example, the correction coefficient is calculated for each workpiece type, but the correction coefficient can also be calculated for each machining condition, including at least one of the following: cutting edge material of the cutting tool, cutting edge shape of the cutting tool, workpiece material, cutting speed, cutting depth, or cutting angle.Similar to the first example, when there are a plurality of combinations of machining conditions and oscillation conditions to be input, and there are a plurality of combinations of theoretical chip lengths and actual chip lengths for each combination of conditions, the correction value calculation unit 16 preferably automatically calculates the correction coefficient based on the average value of the deviation multiplication factors between the theoretical chip length calculated for each combination and the actual chip length.

[0048] The machine tool control apparatus 1A according to the second embodiment can achieve the following effects.

[0049] The machine tool control device 1A according to the second embodiment further includes the correction value calculation unit 16 that calculates the correction value used to correct the chip length, and the calculated chip length is corrected using the correction value calculated by the correction value calculation unit 16. Specifically, the actual chip length detection unit 17 that detects the actual chip length obtained by performing actual machining is further provided, and the correction value is calculated based on the calculated theoretical chip length and the detected actual chip length. This enables the calculation of a more accurate chip length.

[0050] In the machine tool control device 1A according to the second embodiment, the correction value calculation unit 16 calculates the correction value for each machining state. Specifically, the correction value calculation unit 16 calculates the correction value for each machining state, including at least one of the following: 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 depth, or the cutting angle. This enables the calculation of an even more accurate chip length. [Third Embodiment]

[0051] Fig. 15 is a functional block diagram of a machine tool control device 1B according to the third embodiment. As shown in Fig. As shown in FIG. 15, the machine tool control device 1B according to the third embodiment further includes a correction value calculation unit 16A and an actual oscillation amplitude detection unit 18, which is different from the machine tool control device 1 according to the first embodiment. Furthermore, the chip length calculation unit 13B also performs chip length correction, which is different from the chip length calculation unit 13 of the first embodiment. Other configurations are common to the first embodiment.

[0052] The actual oscillation amplitude detection unit 18 detects the actual oscillation amplitude of the cutting path, which is measured by actually performing oscillating cutting under the machining conditions and oscillation conditions used for calculating the theoretical chip length. The actually measured value of the cutting path can be detected using a position detector, such as an encoder, which is typically provided in the servo motor. The detected actual oscillation amplitude is output to the correction value calculation unit 16A, which will be described later.

[0053] The correction value calculation unit 16A calculates the correction value used to correct the chip length. Specifically, the correction value calculation unit 16A calculates the correction value based on the damping rate of the actual oscillation amplitude detected by the actual oscillation amplitude detection unit 18 relative to the oscillation amplitude detected by the state detection unit 12, that is, the target oscillation amplitude value. For example, the damping rate itself is used as the correction value. The calculated correction value is output to the chip length calculation unit 13B, which will be described later.

[0054] Similar to the correction value calculation unit 16 of the second embodiment, the correction value calculation unit 16A preferably calculates the correction value for each machining state, specifically, for at least one of the following elements: the material of the cutting edge of the cutting tool, the shape of the cutting edge of the cutting tool, the workpiece material, the cutting speed, the cutting depth, or the cutting angle.

[0055] The chip length calculation unit 13B calculates the theoretical chip length based on the machining conditions and the oscillation conditions detected by the condition detection unit 12, using the same calculation method used in the chip length calculation unit 13 of the first embodiment. When calculating the chip length using Formula 1 and using the same calculation method used in the chip length calculation unit 13 of the first embodiment, the chip length calculation unit 13B calculates the chip length by substituting the value obtained by multiplying the oscillation amplitude multiplication factor K by the damping rate into Formula 1 as a correction value, instead of using the oscillation amplitude multiplication factor K.

[0056] The following describes the method for correcting the chip length by the chip length calculation unit 13B with reference to the Fig. 16 to 18 described in detail. Fig. Figure 16 is a graph showing the damping rate of the actual measured value relative to the target value of the oscillation amplitude. Fig. Figure 17 is a diagram showing a chip length confirmation screen in which the oscillation amplitude damping rate has been entered. Fig. 18 is a diagram showing a chip length confirmation screen that displays the chip length corrected based on the damping rate of the oscillation amplitude.

[0057] First, similar to the first embodiment described above, the operator inputs the machining conditions including the coordinate value X in the direction of the workpiece diameter, which represents the information about the machining diameter, and the oscillation conditions including the oscillation frequency multiplication factor I and the oscillation amplitude multiplication factor K. Then, as in Fig. As shown in Figure 17, 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. The operator operates the machine tool control unit 1A before and after the above input operation, actually performs oscillation cutting using the machining conditions and oscillation conditions used for calculating the theoretical chip length, and obtains the actual measured values ​​of the cutting path.

[0058] Next, as in Fig. As shown in Figure 16, the correction value calculation unit 16A calculates the damping rate of the actually measured value relative to the command value of the oscillation amplitude by comparing the command value and the actually measured value of the cutting path, and uses the calculated damping rate itself as the correction value. Then, the chip length calculation unit 13B calculates the chip length corrected based on the damping rate, and as shown in Figure 16A, Fig. As shown in Figure 18, the chip length confirmation screen displays the damping rate of the oscillation amplitude, and the displayed chip length is changed to the chip length corrected based on the damping rate.

[0059] The machine tool control apparatus 1B according to the third embodiment can achieve the following effects.

[0060] The machine tool control device 1B according to the third embodiment further includes the actual oscillation amplitude detection unit 18 that detects the actual oscillation amplitude obtained by actually performing the oscillation cutting machining, and the correction value calculation unit 16A calculates the correction value based on the attenuation rate of the actual oscillation amplitude detected by the actual oscillation amplitude detection unit 18 relative to the oscillation amplitude detected by the state detection unit 12. This enables the calculation of a more accurate chip length.

[0061] The present disclosure is not limited to the above-mentioned embodiments, and changes and improvements that can achieve the object of the present disclosure are included in the present disclosure.

[0062] For example, in the second and third embodiments described above, the correction value calculation unit 16, 16A calculates the correction value automatically, but this is not a limitation. The operator can manually input and set the correction values ​​obtained by calculation on an external computer, etc.

[0063] For example, in the third embodiment described above, if the damping rate of the actual oscillation amplitude can be determined from the frequency response of the machine, the correction value can be calculated based on this damping rate. Explanation of reference symbols 1, 1A, 1B Machine tool control unit 11 Input unit 12 Condition recording unit 13, 13A, 13B chip length calculation unit 14 Chip length output unit 15 Chip length display unit 16, 16A Correction value calculation unit 17 Unit for recording the actual chip length 18 Detection unit for the actual oscillation amplitude QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 6744815

[0005]

Claims

[1] A control device for a machine tool that machines a workpiece by relatively oscillating a cutting tool and the workpiece, the control device comprising: a state detecting unit that detects a machining state and an oscillation state; a chip length calculation unit that calculates a chip length based on the machining state and the oscillation state detected by the state detection unit; and a chip length output unit that outputs the chip length calculated by the chip length calculation unit. [2] The control device for a machine tool according to claim 1, further comprising a chip length display unit that displays the chip length outputted by the chip length output unit. [3] The control device for a machine tool according to claim 1 or 2, wherein the state detection unit detects the machining status, including information about a machining diameter, and the oscillation state, including information about the number of oscillations per relative revolution of the cutting tool and the workpiece, and information about the oscillation amplitude relative to a feed amount per relative revolution of the cutting tool and the workpiece. [4] The control device for a machine tool according to any one of claims 1 to 3, further comprising a correction value calculation unit that calculates a correction value used for correcting the chip length, wherein the chip length calculation unit calculates the chip length based on the machining state and the oscillation state detected by the state detection unit, using the correction value calculated by the correction value calculation unit. [5] The control device for a machine tool according to claim 4, further comprising an actual chip length detecting unit that detects an actual chip length obtained by actually performing the machining, wherein the correction value calculating unit calculates the correction value based on the chip length calculated by the chip length calculating unit and the actual chip length detected by the actual chip length detecting unit. [6] The control device for a machine tool according to claim 4, wherein the correction value calculation unit calculates the correction value based on an attenuation rate of the actual oscillation amplitude relative to the oscillation amplitude. [7] The control device for a machine tool according to claim 6, further comprising an actual oscillation amplitude detecting unit that detects the actual oscillation amplitude obtained when the machining is actually carried out, wherein the state detection unit detects the oscillation amplitude, and the damping rate of the actual oscillation amplitude relative to the oscillation amplitude is calculated based on the oscillation amplitude detected by the state detecting unit and the actual oscillation amplitude detected by the actual oscillation amplitude detecting unit. [8] The control device for a machine tool according to any one of claims 4 to 7, wherein the correction value calculation unit calculates the correction value for each machining state. [9] The control device for a machine tool according to claim 8, wherein the correction value calculation unit calculates the correction value for each machining state including at least one of a material of a cutting edge of the cutting tool, a shape of the cutting edge of the cutting tool, a material of the workpiece, a cutting speed, a cutting depth, or a cutting angle.

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