Numerical control device and computer-readable storage medium

Abstract

Provided is a numerical control device that acquires a variation condition for periodically varying a spindle speed, computes the periodically varying spindle speed on the basis of a variation amplitude ratio and a variation frequency ratio included in the variation condition, acquires the temperature of the spindle, and, when the temperature of the spindle exceeds a predetermined temperature threshold value, reduces at least one of or both of the variation amplitude ratio and the variation frequency ratio.

Description

Numerical control device and computer-readable storage medium

[0001] The present disclosure relates to a numerical control device and a computer-readable storage medium.

[0002] Cutting is a type of removal process that creates a desired shape on a workpiece through the relative motion between the tool and the workpiece to be machined. Machine tools perform cutting by attaching the tool or workpiece to a spindle and rotating the spindle. In cutting, "regenerative chatter vibration" can occur. In regenerative chatter vibration, vibration occurs on the machined surface, the chip thickness due to the previous cutting mark and the current cutting mark becomes oscillatory, the cutting force proportional to the chip thickness becomes oscillatory, and vibration of the tool or workpiece is excited. This phenomenon is repeated.

[0003] In order to avoid regenerative chatter vibration, there is a conventional technique for suppressing the vibration of the cutting thickness by varying the spindle rotation speed in a triangular wave or sinusoidal wave form, as disclosed in Patent Document 1, for example.

[0004] International Publication No. 2016 / 181450

[0005] However, periodically varying the spindle speed increases the load on the spindle motor, causing the temperature of the spindle motor to rise. To prevent the temperature of the spindle motor from rising, it is necessary to adjust the amplitude / frequency of the spindle speed fluctuation. Adjusting the amplitude / frequency of the spindle speed fluctuation is complicated.

[0006] In the field of numerical control devices, it is desired to simplify the adjustment of the fluctuation amplitude / fluctuation frequency of the spindle speed.

[0007] A numerical control device that is one aspect of the present disclosure includes a fluctuation condition acquisition unit that acquires fluctuation conditions for periodically fluctuating the spindle speed, a spindle speed calculation unit that calculates the periodically fluctuating vibration spindle speed based on the fluctuation amplitude rate and fluctuation frequency rate included in the fluctuation conditions, a temperature acquisition unit that acquires the temperature of the spindle, and a fluctuation magnification calculation unit that reduces either the fluctuation amplitude rate or the fluctuation frequency rate, or both, when the temperature of the spindle exceeds a predetermined temperature threshold.

[0008] FIG. 1 is a block diagram of a numerical control device of a first embodiment. FIG. 2 is a schematic diagram showing the relationship between a fluctuation frequency rate and a fluctuation amplitude rate. FIG. 3 is a flowchart explaining the operation of the numerical control device of the first embodiment. FIG. 4 is a graph showing changes in the fluctuation amplitude rate and the fluctuation frequency rate in the first embodiment. FIG. 5 is a graph showing changes in the fluctuation amplitude rate and the fluctuation frequency rate in the second embodiment. FIG. 6 is a block diagram of a numerical control device of a fourth embodiment. FIG. 7 is a graph of the frequency spectrum of spindle vibration. FIG. 8 is a flowchart explaining the operation of the numerical control device of the fourth embodiment. FIG. 9 is a graph showing changes in the fluctuation amplitude rate and the fluctuation frequency rate in the fourth embodiment. FIG. 10 is a block diagram of a numerical control device of a fifth embodiment. FIG. 11 is a block diagram of a numerical control device of a sixth embodiment. FIG. 12 is a flowchart explaining the operation of the numerical control device of the sixth embodiment. FIG. 13 is a screen display diagram of the numerical control device of the sixth embodiment. FIG. 14 is a hardware configuration diagram of the numerical control device.

[0009] The numerical control device disclosed herein has a function for suppressing regenerative chatter vibration. Regenerative chatter vibration is vibration caused by undulations on the machined surface that occurred during the previous cutting. When vibration occurs on the machined surface during the previous cutting, the cutting marks from the previous cutting edge and the current cutting edge cause the chip thickness to vibrate. The cutting force, which is proportional to the chip thickness, also vibrates, exciting vibrations in the tool or workpiece.

[0010] The numerical control device suppresses vibration by periodically varying the spindle speed. The numerical control device of this embodiment adjusts the fluctuation magnification of the amplitude and frequency of the spindle speed fluctuation. The greater the amplitude and frequency of the spindle, the greater the effect of suppressing chatter vibration, but the greater the load on the spindle and the higher the temperature of the spindle. The numerical control device calculates the fluctuation frequency rate and fluctuation amplitude rate of the spindle speed to suppress heating of the spindle and suppress chatter vibration.

[0011] (First embodiment) A numerical control device according to the first embodiment will be described below. Fig. 1 is a block diagram of a numerical control device 100 according to the first embodiment. The numerical control device 100 includes a variable condition acquisition unit 10, a spindle speed calculation unit 11, a spindle motor control unit 12, a temperature acquisition unit 13, and a variable magnification calculation unit 14.

[0012] The fluctuation condition acquisition unit 10 acquires the fluctuation conditions of the spindle speed. The fluctuation conditions include the fluctuation amplitude rate initial value RVA ｉｎｉｔ , fluctuation frequency rate initial value RVF ｉｎｉｔ , temperature threshold T ｔｈ The variable conditions are input by the machine tool user, the machine manufacturer.

[0013] The spindle speed calculation unit 11 calculates the spindle speed according to the following formula based on the variable conditions, and outputs it to the spindle motor control unit 12. The spindle motor control unit 12 controls the motor of the machine tool to rotate the motor at a specified spindle speed.

[0014]

[0015] In the above equation, Ω ０ is the reference spindle speed, Ω is the spindle speed, RVA is the fluctuation amplitude rate, and RVF is the fluctuation frequency rate. ０ is the spindle speed specified in the machining program. The spindle speed Ω is the reference spindle speed Ω ０ The fluctuation frequency rate RVF is a coefficient for adjusting the frequency of the spindle speed. The fluctuation amplitude rate is a coefficient for adjusting the amplitude of the spindle speed. The fluctuation frequency rate initial value RVF ｉｎｉｔ is the initial value of the fluctuation frequency RVF. ｉｎｉｔ is the initial value of the fluctuation amplitude rate RVA.

[0016] 2 shows the relationship between the fluctuation frequency rate RVF and the fluctuation amplitude rate RVA. ０ The spindle speed Ω is calculated by periodically varying the spindle speed Ω. By periodically varying the spindle speed Ω, regenerative chatter vibration is suppressed. The fluctuation frequency rate RVF and the fluctuation amplitude rate RVA are calculated by periodically varying the spindle speed Ω. ｓ and a coefficient for adjusting the amplitude A.

[0017] [Amendment based on Rule 91 25.04.2025] The following formula is the relationship between the fluctuation frequency rate RVF, the fluctuation amplitude rate RVA and the reference spindle speed Ω ０ This shows the relationship between

[0018]

[0019] The temperature acquisition unit 13 acquires the temperature of the spindle. There is no particular limitation on the method of acquiring the temperature. The temperature of the spindle is calculated based on the amplitude A and frequency f of the spindle speed Ω. ｓ It is related to the amplitude A and frequency f ｓ The larger one of these is, the higher the temperature of the main shaft becomes.

[0020] [Correction based on Rule 91 25.04.2025] The fluctuation magnification calculation unit 14 calculates the temperature of the spindle and the temperature threshold T ｔｈ and the spindle temperature is compared with the temperature threshold T ｔｈ When the temperature of the spindle exceeds the temperature threshold T ｔｈ If it is equal to or greater than the temperature threshold T ｔｈ If it is not equal to or greater than this, it is determined that cutting should be continued.

[0021] The operation of the numerical control device 100 of the first embodiment will be described with reference to the flowchart of Fig. 3. First, the variable condition acquisition unit 10 acquires the variable conditions (step S1). The spindle speed calculation unit 11 calculates the spindle speed based on the variable magnification factor (step S2). The initial variable magnification factor is the variable amplitude rate initial value RVA acquired by the variable condition acquisition unit 10. ｉｎｉｔ and fluctuation frequency rate initial value RVF ｉｎｉｔ is.

[0022] The operator operates the numerical control device 100, and the machine tool starts cutting (step S3). The temperature acquisition unit 13 acquires the temperature of the spindle. The fluctuation magnification calculation unit 14 calculates the temperature of the spindle and the temperature threshold T ｔｈ When the temperature of the spindle reaches the temperature threshold T ｔｈ If the temperature of the spindle is smaller than the temperature threshold T ｔｈ In the above cases (step S4; Yes), the fluctuation magnification calculation unit 14 decreases the fluctuation magnification (at least one of the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF) (step S6).

[0023] The fluctuation magnification calculation unit 14 waits for a certain period of time (step S7), and then calculates the temperature of the spindle and the temperature threshold T ｔｈ The temperature of the spindle is compared with the temperature threshold T ｔｈ If the temperature of the spindle is smaller than the temperature threshold T ｔｈ In the above cases (Step S8; No), the fluctuation magnification calculation unit 14 suspends cutting (Step S9).

[0024] As described above, the numerical control device 100 of the first embodiment acquires the temperature of the spindle, and determines whether the temperature of the spindle is equal to or exceeds the temperature threshold T ｔｈ When the spindle speed Ω exceeds ｓ The numerical control device 100 acquires the temperature of the spindle and decreases at least one of the frequency A and the temperature threshold T ｔｈ If the temperature of the spindle is lower than the temperature threshold T ｔｈ If it is greater than this, cutting is interrupted. This automatically adjusts the fluctuation magnification (fluctuation amplitude rate RVA, fluctuation frequency rate RVF) of the periodic fluctuation of the spindle speed Ω, thereby suppressing the temperature rise of the spindle. The numerical control device 100 automatically adjusts the spindle temperature, reducing the burden on the operator.

[0025] Second Embodiment A numerical control device 100 according to a second embodiment reduces the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF to minimum values. The configuration of the numerical control device according to the second embodiment is substantially the same as that of the numerical control device according to the first embodiment, and therefore only the differences will be described.

[0026] The fluctuation condition acquisition unit 10 acquires the fluctuation amplitude rate initial value RVA ｉｎｉｔ , fluctuation frequency rate initial value RVF ｉｎｉｔ , temperature threshold T ｔｈ In addition to this, the minimum fluctuation amplitude rate RVA ｍｉｎ , minimum fluctuation frequency rate RVF ｍｉｎ Get.

[0027] [Correction based on Rule 91 25.04.2025] The fluctuation magnification calculation unit 14 calculates the temperature of the spindle and the temperature threshold T ｔｈ and the spindle temperature is compared with the temperature threshold T ｔｈ When the fluctuation frequency rate RVF exceeds the minimum fluctuation frequency rate RVFｍｉｎ or reduce the fluctuation amplitude rate RVA to the minimum fluctuation amplitude rate RVA ｍｉｎ or reduce it to, or both.

[0028] [Correction based on Rule 91 25.04.2025] Figure 4 shows the changes in the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF. ｔｈ The fluctuation magnification is reduced to the minimum value at time t' when the fluctuation amplitude rate RVA exceeds the fluctuation amplitude rate initial value RVA. ｉｎｉｔ From the minimum fluctuation amplitude rate RVA ｍｉｎ (2) The fluctuation frequency rate RVF is reduced to the fluctuation frequency rate initial value RVF ｉｎｉｔ From the minimum fluctuation frequency rate RVF ｍｉｎ or (3) implementing both (1) and (2).

[0029] When the fluctuation magnification is reduced, the temperature of the spindle decreases. The fluctuation magnification calculation unit 14 waits for a certain period of time, and then determines whether the temperature of the spindle is below the temperature threshold T ｔｈ If it is equal to or greater than the temperature threshold T ｔｈ If not, continue cutting.

[0030] According to the numerical control device 100 of the second embodiment, the load on the spindle motor can be quickly reduced by reducing the fluctuation magnification factor to the minimum value at once.

[0031] (Third embodiment) A numerical control device 100 of a third embodiment gradually decreases the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF. The configuration of the numerical control device 100 of the third embodiment is substantially the same as that of the numerical control device 100 of the first embodiment, so only the differences will be described.

[0032] The fluctuation condition acquisition unit 10 acquires the fluctuation amplitude rate initial value RVA ｉｎｉｔ , fluctuation frequency rate initial value RVF ｉｎｉｔ , temperature threshold T ｔｈ In addition to this, the fluctuation amplitude rate slope RVA ｃｏｅｆ , fluctuation frequency rate slope RVF ｃｏｅｆ Get.

[0033] The fluctuation magnification calculation unit 14 calculates the temperature of the spindle and the temperature threshold T ｔｈ and the spindle temperature is compared with the temperature threshold T ｔｈ If the fluctuation frequency rate RVF or the fluctuation amplitude rate RVA exceeds this value, the fluctuation frequency rate RVF or the fluctuation amplitude rate RVA, or both, are gradually decreased.

[0034] [Correction based on Rule 91 25.04.2025] Figure 5 shows the changes in the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF. ｔｈ At time t' when the fluctuation magnification exceeds t, the fluctuation magnification is decreased for a predetermined time with a predetermined slope. The method of decreasing the fluctuation magnification includes: (1) decreasing the fluctuation amplitude rate RVA for a predetermined time (referred to as Δt time) with a fluctuation amplitude rate slope RVA ｃｏｅｆ (2) The fluctuation frequency rate RVF is decreased by a fluctuation frequency rate gradient RVF for a predetermined time (referred to as Δt time). ｃｏｅｆ (3) There is a method to perform both (1) and (2).

[0035] When the fluctuation magnification is reduced, the temperature of the spindle decreases. The fluctuation magnification calculation unit 14 determines whether the temperature of the spindle is below the temperature threshold T ｔｈ If it is equal to or greater than the temperature threshold T ｔｈ If not, continue cutting.

[0036] [Correction based on Rule 91 25.04.2025] In the numerical control device 100 of the third embodiment, the change in the temperature of the spindle motor is checked while decreasing the fluctuation magnification, and the decrease in the fluctuation magnification is stopped when the temperature of the spindle motor has dropped sufficiently. According to the numerical control device 100 of the third embodiment, by stopping the decrease in the fluctuation magnification when the temperature condition of the spindle motor is satisfied, it becomes possible to continue cutting with a larger fluctuation magnification, and the effect of suppressing regenerative chatter vibration is improved.

[0037] (Fourth embodiment) A numerical control device 100 according to a fourth embodiment has a frequency analysis function, and adjusts the fluctuation frequency rate RVF and the fluctuation amplitude rate RVA while comparing the regenerative chatter vibration with a predetermined threshold value, and suppresses the regenerative chatter vibration to the predetermined threshold value and adjusts the fluctuation frequency rate RVF and the fluctuation amplitude rate RVA until the temperature of the spindle reaches the temperature threshold value T ｔｈ The fluctuation frequency rate RVF and fluctuation amplitude rate RVA are calculated so that they do not exceed the above values.

[0038] 6 is a block diagram of a numerical control device 100 according to the fourth embodiment. The numerical control device 100 according to the fourth embodiment includes a regenerative chatter vibration detection unit 15. The configuration of the numerical control device 100 according to the fourth embodiment is substantially the same as that of the numerical control device 100 according to the third embodiment, and therefore only the differences will be described.

[0039] The fluctuation condition acquisition unit 10 acquires the fluctuation amplitude rate initial value RVA ｉｎｉｔ , fluctuation frequency rate initial value RVF ｉｎｉｔ , temperature threshold T ｔｈ , fluctuation amplitude rate slope RVA ｃｏｅｆ , fluctuation frequency rate slope RVF ｃｏｅｆ In addition, the chatter vibration threshold K ｔｈ (or chatter vibration threshold K ｔｈ (calculation formula) is obtained.

[0040] The fluctuation magnification calculation unit 14 calculates the temperature of the spindle and the temperature threshold T ｔｈ and the spindle temperature is compared with the temperature threshold T ｔｈ If the above is true, the fluctuation frequency rate RVF or the fluctuation amplitude rate RVA, or both, are gradually decreased. The method of gradually decreasing them is the same as in the third embodiment, and therefore a description thereof will be omitted.

[0041] The regenerative chatter vibration detection unit 15 detects regenerative chatter vibration. Methods for detecting regenerative chatter vibration include (1) a method of performing spectrum analysis on signals such as cutting force, displacement, cutting sound, and current, (2) a method of taking the root mean square of the above-mentioned signals, and (3) a method using machine learning such as deep learning.

[0042] An example of a frequency spectrum is shown in Figure 7. The regenerative chatter vibration detection unit 15 performs a Fourier transform on the vibration of the spindle to obtain the frequency spectrum. In Figure 7, the horizontal axis is frequency, and the vertical axis is the spectrum of amplitude corresponding to that frequency. Machine vibration during cutting contains a complex mixture of many frequencies. When a frequency analysis is performed, the tool cutting edge passing frequency component and its harmonic components appear strongly. The frequency of the harmonic components is an integer multiple of the cutting edge passing frequency. The regenerative chatter vibration detection unit 15 distinguishes strong vibrations other than cutting edge passing vibration and harmonics as regenerative chatter vibration.

[0043] In the method of taking the root mean square of the signal, the root mean square of the above-mentioned signal is taken in the time domain to calculate the effective value of the signal.The occurrence of regenerative chatter vibration can be detected by determining the level of the effective value.In the method using deep learning, a learning model is created in advance to extract the characteristics of regenerative chatter vibration from the input signal, and the regenerative chatter signal occurring in the signal is detected using the learning model.

[0044] The fluctuation magnification calculation unit 14 calculates a fluctuation frequency rate RVF and a fluctuation amplitude rate RVA that cause the reproduced chatter signal to fall within an allowable range. In the root mean square method described above, a fluctuation frequency rate RVF and a fluctuation amplitude rate RVA are calculated so that the effective value of the signal is equal to or less than a predetermined threshold. In the method using deep learning, for example, a learning model is created that determines whether the reproduced chatter signal falls within the allowable range.

[0045] In the method using spectrum analysis, the amplitude of the regenerative chatter vibration obtained by Fourier transform and the chatter vibration threshold K ｔｈ Compare with the chatter vibration threshold K ｔｈ indicates the allowable limit of regenerative chatter vibration. ｔｈ is the limit value that does not affect cutting. ｔｈ In this example, the chatter vibration threshold K ｔｈ The calculation formula is defined as follows: The calculation formula is: the coefficient multiplied by the maximum amplitude of the harmonic of the cutting edge passing frequency is the chatter vibration threshold K ｔｈ The fluctuation magnification calculation unit 14 selects the maximum value of the amplitude of the harmonic from the amplitude spectrum, multiplies the selected maximum value by a certain coefficient, and calculates the chatter vibration threshold K ｔｈ Calculate.

[0046] The fluctuation magnification calculation unit 14 calculates the chatter vibration threshold value K ｔｈ and the amplitude of the regenerative chatter vibration, and the amplitude of the regenerative chatter vibration is compared to the chatter vibration threshold K ｔｈ If the fluctuation magnification factor (either the fluctuation amplitude rate RVA or the fluctuation frequency rate RVF, or both) is reduced, the amplitude of the regenerative chatter vibration gradually increases. The fluctuation magnification factor calculation unit 14 calculates the amplitude of the regenerative chatter vibration when the amplitude of the regenerative chatter vibration is greater than or equal to the chatter vibration threshold value Kｔｈ When it reaches this value, the decrease in the fluctuation multiplier stops.

[0047] Chatter vibration threshold K ｔｈ The fluctuation amplitude rate RVA at the time when it reaches the fluctuation amplitude rate setting value RVA ｓｅｔ The fluctuation frequency rate RVF is called the fluctuation frequency rate setting value RVF ｓｅｔ It is called.

[0048] The variable magnification calculation unit 14 continues cutting by fixing the variable magnification to a set value, and calculates the temperature of the spindle and the temperature threshold T ｔｈ The fluctuation magnification calculation unit 14 compares the temperature of the spindle with the temperature threshold value T ｔｈ If it is smaller than the temperature threshold T ｔｈ If it is more than this, the cutting is stopped.

[0049] [Correction based on Rule 91 25.04.2025] The operation of the numerical control device 100 of the fourth embodiment will be described with reference to the flowchart in Figure 8. This flowchart illustrates an example in which regenerative chatter vibration is detected using spectral analysis. The method for detecting regenerative chatter vibration does not have to be spectral analysis. First, the fluctuation condition acquisition unit 10 acquires fluctuation conditions (step S21). The spindle speed calculation unit 11 calculates the spindle speed (step S22). The initial fluctuation magnification is calculated by the fluctuation amplitude rate initial value RVA acquired by the fluctuation condition acquisition unit 10. ｉｎｉｔ and fluctuation frequency rate initial value RVF ｉｎｉｔ is.

[0050] The operator operates the numerical control device 100, and the machine tool starts cutting (step S23). The temperature acquisition unit 13 acquires the temperature of the spindle. The fluctuation magnification calculation unit 14 calculates the temperature of the spindle and the temperature threshold value T ｔｈ When the temperature of the spindle reaches the temperature threshold T ｔｈ If the temperature of the spindle is smaller than the temperature threshold T ｔｈ In the above cases (step S24; Yes), the fluctuation magnification calculation unit 14 decreases the fluctuation magnification (at least one of the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF) (step S26).

[0051] [Correction based on Rule 91 25.04.2025] The fluctuation magnification calculation unit 14 calculates the amplitude of the regenerative chatter vibration and the chatter vibration threshold K ｔｈ The amplitude of the regenerative chatter vibration is compared with the chatter vibration threshold value K ｔｈ If the amplitude of the regenerative chatter vibration is smaller than the chatter vibration threshold K (step S27; No), the fluctuation magnification calculation unit 14 proceeds to step S26 and decreases the fluctuation magnification. ｔｈ The fluctuation magnification is decreased unless the amplitude of the regenerative chatter vibration exceeds the chatter vibration threshold K ｔｈ If it is equal to or greater than this (step S27; Yes), the fluctuation magnification calculation unit 14 calculates the chatter vibration threshold value K ｔｈ The fluctuation magnification in the range not exceeding the fluctuation magnification setting value (fluctuation amplitude rate setting value RVA ｓｅｔ and variable frequency rate setting value RVF ｓｅｔ )

[0052] The fluctuation magnification calculation unit 14 calculates the temperature of the spindle and the temperature threshold T ｔｈ The temperature of the spindle is compared with the temperature threshold T ｔｈ If the result is as above (Step S28; Yes), the fluctuation magnification calculation unit 14 suspends cutting (Step S29). ｔｈ If it is smaller (Step S28; No), the fluctuation magnification calculation unit 14 continues cutting (Step S30).

[0053] 9 shows the changes in the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF in the fourth embodiment. ｉｎｉｔ and fluctuation frequency rate initial value RVF ｉｎｉｔ The spindle speed Ω is calculated based on the fluctuation amplitude rate initial value RVA ｉｎｉｔ and fluctuation frequency rate initial value RVF ｉｎｉｔ When the spindle speed is varied based on the temperature threshold T ｔｈ If it is smaller, the fluctuation magnification calculation unit 14 decreases the fluctuation magnification. The methods for decreasing the fluctuation magnification include: (1) decreasing the fluctuation frequency rate slope RVF ｃｏｅｆ (2) Decrease the fluctuation frequency rate RVF by ｃｏｅｆ(3) A method of performing both (1) and (2) is available. When the fluctuation magnification is reduced, the amplitude of the regenerative chatter vibration gradually increases. When the amplitude of the regenerative chatter vibration reaches the chatter vibration threshold K ｔｈ If the time when the fluctuation frequency rate RVF and the fluctuation amplitude rate RVA at t' are exceeded is defined as t', the fluctuation frequency rate set value RVF ｓｅｔ and fluctuation amplitude rate setting value RVA ｓｅｔ Fix it to.

[0054] The fluctuation magnification calculation unit 14 calculates the fluctuation frequency rate setting value RVF ｓｅｔ and fluctuation amplitude rate setting value RVA ｓｅｔ When cutting is performed, the temperature of the spindle is equal to or exceeds the temperature threshold T ｔｈ As a result, it is determined whether the temperature of the spindle exceeds the temperature threshold T ｔｈ If the temperature of the spindle does not exceed the temperature threshold T ｔｈ If it exceeds this limit, cutting is stopped.

[0055] According to the numerical control device 100 of the fourth embodiment, it is possible to automatically search for the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF that keep the regenerative chatter vibration within an acceptable range and keep the temperature of the spindle within an acceptable range.

[0056] Fifth Embodiment A numerical control device 100 according to a fifth embodiment stores the fluctuation multiplier calculated by the fluctuation multiplier calculation unit 14 in association with a block of a machining program. FIG. 10 is a block diagram of the numerical control device 100 according to the fifth embodiment. The numerical control device 100 according to the fifth embodiment includes a fluctuation multiplier storage unit 16 that stores the blocks of a machining program in association with the fluctuation multipliers (fluctuation amplitude rate and fluctuation frequency rate). The configuration of the numerical control device according to the fifth embodiment shown in FIG. 10 is substantially the same as that of the numerical control device 100 according to the first embodiment, and therefore only the differences will be described. The function of the fluctuation multiplier storage unit 16 can also be applied to the numerical control devices 100 according to the second to fourth embodiments and the sixth embodiment.

[0057] According to the numerical control device 100 of the fifth embodiment, by storing the block of the machining program and the variable magnification ratio in association with each other, it is possible to use the variable magnification ratio that has already been calculated when the same machining program is executed. This eliminates the need to readjust the variable magnification ratio, and reduces the physical load on the spindle and the calculation load required to adjust the spindle speed.

[0058] (Sixth embodiment) A numerical control device 100 of the sixth embodiment displays the variable magnification factor and the temperature change of the spindle when and after cutting is interrupted, and when the spindle is cooled to a predetermined set value, resets the variable magnification factor and resumes cutting.

[0059] 11 is a block diagram of a numerical control device 100 according to the sixth embodiment. The numerical control device 100 according to the sixth embodiment includes a display control unit 17. The configuration of the numerical control device 100 according to the sixth embodiment is substantially the same as that of the numerical control device 100 according to the first embodiment, and therefore only the differences will be described. Note that the functions of the numerical control device 100 according to the sixth embodiment can also be applied to the numerical control devices 100 according to the first to fifth embodiments as functions to be used after cutting is interrupted.

[0060] The display control unit 17 displays at least the fluctuation amplitude rate RVA, fluctuation frequency rate RVF, and spindle temperature during and after the interruption of cutting as graphs and numerical values ​​on the display unit 70. Note that the fluctuation amplitude rate RVA, fluctuation frequency rate RVF, and spindle temperature may be displayed on the display unit 70 from before the interruption of cutting.

[0061] The fluctuation magnification calculation unit 14 compares the temperature of the spindle after cutting is interrupted with a predetermined set value, and when the temperature of the spindle is cooled to the set value, the values ​​of the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF at the time of interruption of cutting are set to the fluctuation amplitude rate initial value RVA. ｉｎｉｔ and fluctuation frequency rate initial value RVF ｉｎｉｔ Reset to.

[0062] The operation of the numerical control device 100 of the sixth embodiment will be described with reference to the flowchart of FIG. ｔｈIf the temperature of the spindle exceeds the predetermined value, the fluctuation magnification calculation unit 14 suspends cutting (step S31). After suspending cutting, the fluctuation magnification calculation unit 14 acquires the temperature of the spindle and determines whether the temperature of the spindle is equal to or lower than a predetermined set value. If the temperature of the spindle is higher than the predetermined set value (step S32; No), the fluctuation magnification calculation unit 14 waits for a certain period of time (step S33) and again compares the temperature of the spindle with the predetermined set value.

[0063] If the temperature of the spindle is equal to or lower than the predetermined set value (step S32; Yes), the fluctuation magnification calculation unit 14 sets the values ​​of the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF at the time of interruption of cutting to the fluctuation amplitude rate initial value RVA ｉｎｉｔ and fluctuation frequency rate initial value RVF ｉｎｉｔ (Step S34). The fluctuation magnification calculation unit 14 resets the reset fluctuation amplitude rate initial value RVA ｉｎｉｔ and fluctuation frequency rate initial value RVF ｉｎｉｔ Then, cutting is resumed (step S35).

[0064] [Correction based on Rule 91 25.04.2025] After interrupting cutting, the display control unit 17 displays graphs and numerical values ​​of the fluctuation amplitude rate RVA, fluctuation frequency rate RVF, and spindle temperature on the display unit 70. Figure 13 is an example of a display screen showing changes in the fluctuation amplitude rate RVA, fluctuation frequency rate RVF, and spindle temperature when cutting is repeatedly interrupted and restarted. The fluctuation amplitude rate RVA and fluctuation frequency rate RVF gradually decrease, and at the current time, the fluctuation amplitude rate RVA is "0.16" and the fluctuation frequency rate RVF is "0.10". The spindle temperature also decreases in accordance with the changes in the fluctuation amplitude rate RVA and fluctuation frequency rate RVF, and at the current time, the spindle temperature is "121 degrees". The spindle temperature is measured at a temperature threshold T ｔｈ Since the minimum value of the fluctuation amplitude rate RVA is exceeded, it is necessary to reset the fluctuation conditions. This display screen is an example of the display screen of the second embodiment. ｍｉｎ and the minimum fluctuation frequency rate RVF ｍｉｎ On the display screen of the third embodiment, the fluctuation amplitude rate gradient RVA ｃｏｅｆ and fluctuation frequency rate slope RVF ｃｏｅｆ The display screen of the fourth embodiment may display the frequency components of the regenerative chatter vibration.

[0065] [Correction based on Rule 91 25.04.2025] According to the numerical control device 100 of the sixth embodiment, after interrupting cutting, the fluctuation amplitude rate RVA and the fluctuation frequency rate RVF at the time of interrupting cutting are set to the fluctuation amplitude rate initial value RVA ｉｎｉｔ and fluctuation frequency rate initial value RVF ｉｎｉｔ This allows the variable conditions to be set automatically.

[0066] Furthermore, in the numerical control device 100 of the sixth embodiment, the fluctuation amplitude rate RVA, fluctuation frequency rate RVF, and spindle temperature after cutting is interrupted are displayed on the display unit 70. The values ​​of the fluctuation amplitude rate RVA and fluctuation frequency rate RVF are controlled automatically, but by displaying values ​​related to the control, the operator can check the control status.

[0067] [Correction based on Rule 91 25.04.2025] The hardware configuration of a numerical control device 100 to which the present disclosure is applied will be described below. Fig. 14 is a hardware configuration diagram of the numerical control device 100. As shown in Fig. 14, the numerical control device 100 includes a CPU 111 that controls the entire numerical control device 100, a ROM 112 that records programs and data, and a RAM 113 for temporarily expanding data. The CPU 111 reads out a system program recorded in the ROM 112 via a bus and executes regenerative chatter vibration avoidance in accordance with the system program.

[0068] The nonvolatile memory 114 is backed up by, for example, a battery (not shown), and retains its stored state even when the power to the numerical control device 100 is turned off. The nonvolatile memory 114 stores various data such as programs read from the external device 120 via the interfaces 115, 118, and 119 and operation inputs input via the input unit 30. The nonvolatile memory 114 may also store programs and data for executing the numerical control device 100 of this embodiment. The display unit 70 also displays various data, measurement results, causes of invalid data, etc.

[0069] The interface 115 is an interface for connecting the numerical control device 100 to an external device 120 such as an adapter. Programs, various parameters, etc. are loaded from the external device 120. The interface 118 is an interface for connecting the numerical control device 100 to a display unit 70 such as a liquid crystal display. The display unit 70 displays various data loaded into memory, data obtained as a result of executing programs, etc. The interface 119 is an interface for connecting the numerical control device 100 to an input unit 30 such as a keyboard or pointing device. The input unit 30 passes commands, data, etc. based on operations by an operator to the CPU 111 via the interface 119.

[0070] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the gist of the present disclosure derived from the claims and their equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these.

[0071] [Correction based on Rule 91, April 25, 2025] The following supplementary notes are further disclosed regarding the above-described embodiment and modified examples. (Supplementary Note 1) A numerical control device (100) includes a fluctuation condition acquisition unit (10) that acquires fluctuation conditions for periodically fluctuating a spindle speed, a spindle speed calculation unit (11) that calculates a periodically fluctuating vibration spindle speed based on a fluctuation amplitude rate and a fluctuation frequency rate included in the fluctuation conditions, a temperature acquisition unit (13) that acquires the temperature of the spindle, and a fluctuation magnification calculation unit (14) that reduces either or both of the fluctuation amplitude rate and the fluctuation frequency rate when the temperature of the spindle exceeds a predetermined temperature threshold. (Supplementary Note 2) After reducing either or both of the fluctuation amplitude rate and the fluctuation frequency rate, the fluctuation magnification calculation unit (14) suspends cutting if the temperature of the spindle exceeds the predetermined temperature threshold, and continues cutting if the temperature of the spindle does not exceed the predetermined threshold. (Supplementary Note 3) The fluctuation amplitude rate is a coefficient of the amplitude of the spindle speed, and the fluctuation frequency rate is a coefficient of the frequency of the spindle speed. (Supplementary Note 4) The fluctuation condition acquisition unit (10) acquires one or both of the minimum value of the fluctuation amplitude rate and the minimum value of the fluctuation frequency rate, and the fluctuation magnification calculation unit (14) reduces the fluctuation amplitude rate to a minimum value, or reduces the fluctuation frequency rate to a minimum value, or reduces both to a minimum value, when the temperature of the spindle exceeds a predetermined temperature threshold. (Supplementary Note 5) The fluctuation condition acquisition unit (10) acquires one or both of the slope of the fluctuation amplitude rate and the slope of the fluctuation frequency rate, and the fluctuation magnification calculation unit (14) reduces the fluctuation amplitude rate at the slope of the fluctuation amplitude rate, or reduces the fluctuation frequency rate at the slope of the fluctuation frequency rate, or reduces both, when the temperature of the spindle exceeds a predetermined temperature threshold. (Supplementary Note 6) The numerical control device (100) includes a regenerative chatter vibration detection unit (15) that detects regenerative chatter vibration, and the fluctuation magnification calculation unit (14) reduces one or both of the fluctuation amplitude rate and the fluctuation frequency rate until the regenerative chatter vibration falls within an allowable range. (Supplementary Note 7) The fluctuation magnification calculation unit (14) continues cutting by maintaining the fluctuation amplitude rate and the fluctuation frequency rate at the time when the amplitude of the regenerative chatter vibration reaches a predetermined amplitude threshold, interrupts cutting when the temperature of the spindle exceeds a predetermined temperature threshold, and continues cutting when the temperature of the spindle does not exceed the predetermined threshold.(Supplementary Note 8) The numerical control device (100) includes a fluctuation magnification storage unit (16) that stores blocks of a machining program and the fluctuation amplitude rate and fluctuation frequency rate calculated by the fluctuation magnification calculation unit (14) when the blocks are executed, in association with each other. (Supplementary Note 9) After interrupting the cutting, the fluctuation magnification calculation unit (14) waits until the temperature of the spindle drops to a predetermined set value, resets the fluctuation amplitude rate and fluctuation frequency rate to the values ​​at the time of interruption of the cutting as initial values, and resumes cutting. (Supplementary Note 10) The numerical control device (100) includes a display control unit (17) that displays changes in the fluctuation amplitude rate and fluctuation frequency rate on a display unit. (Supplementary Note 11) The computer-readable storage medium (112, 113, 114) stores instructions for causing one or more processors (111) to execute processing to acquire fluctuation conditions for periodically fluctuating the spindle speed, calculate the periodically fluctuating spindle speed based on a fluctuation amplitude rate and a fluctuation frequency rate included in the fluctuation conditions, acquire the temperature of the spindle, and reduce at least one or both of the fluctuation amplitude rate and the fluctuation frequency rate when the temperature of the spindle exceeds a predetermined temperature threshold.

[0072] REFERENCE SIGNS LIST 100 Numerical control device 10 Variable condition acquisition unit 11 Spindle speed calculation unit 12 Spindle motor control unit 13 Temperature acquisition unit 14 Variable magnification calculation unit 15 Regenerative chatter vibration detection unit 16 Variable magnification storage unit 17 Display control unit 111 CPU 112 ROM 113 RAM 114 Non-volatile memory

Claims

1. A numerical control device comprising: a variation condition acquisition unit that acquires variation conditions for periodically varying the spindle speed; a spindle speed calculation unit that calculates a periodically varying oscillating spindle speed based on a variation amplitude ratio and a variation frequency ratio included in the variation conditions; a temperature acquisition unit that acquires the temperature of the spindle; and a variation magnification calculation unit that decreases one or both of the variation amplitude ratio or the variation frequency ratio when the temperature of the spindle exceeds a predetermined temperature threshold.

2. The numerical control device according to claim 1, wherein the variation magnification calculation unit interrupts cutting when the temperature of the spindle exceeds a predetermined temperature threshold after decreasing one or both of the variation amplitude ratio or the variation frequency ratio, and continues cutting when the temperature of the spindle does not exceed the predetermined threshold.

3. The numerical control device according to claim 1, wherein the variation amplitude ratio is a coefficient of the amplitude of the spindle speed, and the variation frequency ratio is a coefficient of the frequency of the spindle speed.

4. The variation condition acquisition unit acquires one or both of the minimum value of the variation amplitude ratio or the minimum value of the variation frequency ratio, and the variation magnification calculation unit decreases the variation amplitude ratio to the minimum value, or decreases the variation frequency ratio to the minimum value, or decreases both to the minimum value when the temperature of the spindle exceeds a predetermined temperature threshold. The numerical control device according to claim 1.

5. The variation condition acquisition unit acquires one or both of the slope of the variation amplitude ratio or the slope of the variation frequency ratio, and the variation magnification calculation unit decreases the variation amplitude ratio by the slope of the variation amplitude ratio, or decreases the variation frequency ratio by the slope of the variation frequency ratio, or decreases both when the temperature of the spindle exceeds a predetermined temperature threshold. The numerical control device according to claim 1.

6. [Correction based on Rule 91, 25.04.2025] Comprising a chatter vibration detection unit that detects regenerative chatter vibration, and the variation magnification calculation unit decreases one or both of the variation amplitude ratio or the variation frequency ratio until the regenerative chatter vibration falls within an allowable range. The numerical control device according to claim 1.

7. The variation magnification calculation unit maintains the variation amplitude ratio and the variation frequency ratio at the time when the amplitude of the regenerative chatter vibration reaches a predetermined amplitude threshold and continues cutting, interrupts cutting when the temperature of the spindle exceeds a predetermined temperature threshold, and continues cutting when the temperature of the spindle does not exceed the predetermined threshold. The numerical control device according to claim 6.

8. The numerical control device according to claim 1, further comprising a variation magnification storage unit that associates and stores a block of a machining program with a variation amplitude ratio and a variation frequency ratio calculated by the variation magnification calculation unit during execution of the block.

9. The variation magnification calculation unit waits until the temperature of the spindle drops to a predetermined set value after the interruption of cutting, resets the variation amplitude ratio and the variation frequency ratio at the time of interruption of cutting as initial values, and resumes cutting. The numerical control device according to claim 2.

10. The numerical control device according to claim 9, further comprising a display control unit that causes a display unit to display changes in the variation amplitude ratio and the variation frequency ratio.

11. A computer-readable storage medium storing instructions for causing one or more processors to acquire variation conditions for periodically varying a spindle speed, calculate a periodically varying spindle speed based on the variation amplitude ratio and the variation frequency ratio included in the variation conditions, acquire the temperature of the spindle, and when the temperature of the spindle exceeds a predetermined temperature threshold, reduce at least one or both of the variation amplitude ratio or the variation frequency ratio.

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