A tool breakage identification method based on power variation amplitude of machine tool spindle

Abstract

The present application belongs to the technical field of numerical control processing monitoring, and particularly relates to a tool breakage identification method based on the power change amplitude of a machine tool spindle, which specifically comprises the following steps: a first part processing tool breakage monitoring strategy: performing numerical control program segmentation, obtaining the maximum power value and the minimum power value when the spindle is idling, calculating the spindle idling power change amplitude value, and setting the first part processing power change amplitude monitoring value; during part processing, the maximum power value and the minimum power value are obtained; the first part processing power change amplitude value is calculated; and it is observed whether the first part processing power change amplitude value is less than the first part processing power change amplitude monitoring value for 7 consecutive monitoring segments; if yes, a tool breakage alarm is reported and the machine is stopped. The method also realizes tool breakage monitoring for the first part processing of a structural part, and avoids the quality risks caused by risky processing due to the lack of monitoring data for the first part processing.

Description

Technical Field

[0001] This invention belongs to the field of CNC machining monitoring technology, specifically a tool breakage identification method based on the variation amplitude of machine tool spindle power. Background Technology

[0002] In CNC machining of structural components, cutting tools gradually wear down and break over time, sometimes even fracturing, leading to reduced machining efficiency and decreased part quality. Since the cutting tool is in direct contact with the workpiece, its integrity directly affects the dimensional accuracy and surface quality of the part. If a tool breakage is not detected promptly, it can easily cause serious consequences such as tool breakage damaging the part, inaccurate part dimensions, friction burns, and damage to the machine tool spindle. Therefore, during CNC machining, it is crucial to constantly monitor for tool breakage and promptly detect and replace any broken tools. Currently, in CNC machining, tool breakage detection relies heavily on operator experience, making it highly susceptible to human error and prone to delays in responding to abnormal situations. Consequently, machining quality problems frequently arise due to tool breakage.

[0003] Existing patents, such as Chinese invention patent CN115922442A entitled "A Tool Breakage Identification Method Based on Machine Tool Spindle Power Variation Amplitude," disclose the following: A real-time monitoring method and related device for tool wear and breakage based on spindle vibration signals. By synchronously collecting spindle vibration and internal data of the CNC system, power spectrum analysis is performed on the vibration data after noise reduction to obtain power spectrum frequency band energy indicators reflecting tool wear and dimensionless monitoring indicators reflecting tool breakage. The indicators are then fused to obtain a comprehensive monitoring indicator reflecting the tool status. An effective method for setting tool wear and breakage thresholds is proposed. Once the comprehensive monitoring indicator exceeds the failure threshold, the tool failure is determined by the material removal rate increment. This eliminates false alarms caused by the instantaneous switching of working parameters and accurately identifies the tool status. However, the data in the above documents comes from the triaxial acceleration sensor data of the machine tool peripheral. Deploying a triaxial acceleration sensor on the machine tool spindle not only involves complicated sensor wiring, but also the rationality of the deployment location. The vibration of the tool is transmitted to the sensor, involving the tool holder, spindle and other media, which can easily lead to vibration transmission distortion. In addition, the cost of peripheral vibration sensors is relatively high. Summary of the Invention

[0004] The purpose of this invention is to address the problem that tool breakage during CNC machining of structural components can easily lead to machining quality accidents. This invention provides a tool breakage identification method based on the variation of machine tool spindle power, so as to provide timely warning of tool breakage and avoid part scrapping and machine tool failure.

[0005] To achieve the above-mentioned objectives, the technical solution provided in this application is as follows:

[0006] A method for identifying tool breakage based on the variation amplitude of machine tool spindle power includes the following steps:

[0007] S1: Tool breakage monitoring strategy for the first part:

[0008] The CNC program is segmented. When the spindle is idling, the maximum and minimum power values ​​are obtained, the spindle idling power variation range is calculated, and the power variation range monitoring value for the first part is set. When the part is being machined, the maximum and minimum power values ​​are obtained; the power variation range for the first part is calculated; it is observed whether the power variation range for the first part is less than the power variation range monitoring value for the first part for 7 consecutive monitoring segments. If so, a tool breakage alarm is triggered and the machine is stopped.

[0009] S2: Tool breakage monitoring strategy for the second part:

[0010] When the spindle is idling, acquire the maximum and minimum power values; calculate the spindle idling power variation range; superimpose the spindle idling power variation range value for the first part, and set the power variation range monitoring value for the second part; when the part is being processed, acquire the maximum and minimum power values; calculate the power variation range value for the second part; observe whether the power variation range value for the second part is less than the power variation range monitoring value for the second part for three consecutive monitoring segments, and whether the power variation range monitoring value for the second part is less than the power variation range value for the first part. If so, trigger a tool breakage alarm and stop the machine.

[0011] S3: Tool breakage monitoring strategy for the third part:

[0012] When the spindle is idling, acquire the maximum and minimum power values; calculate the spindle idling power variation range; superimpose the spindle idling power variation range value for the second part, and set the power variation range monitoring value for the third part; when the part is being processed, acquire the maximum and minimum power values; calculate the power variation range value for the third part; observe whether the power variation range value for the third part is lower than the power variation range monitoring value for the third part for two consecutive monitoring segments, and whether the power variation range monitoring value for the third part is lower than the power variation range values ​​for the first and second parts. If so, trigger a tool breakage alarm and stop the machine.

[0013] S4: Tool breakage monitoring strategy for the i-th part, i≥4:

[0014] During part processing, the maximum and minimum power values ​​are obtained; the power variation range of the i-th part is calculated; it is observed whether the power variation range of the i-th part is less than the power variation range monitoring value of the i-th part, and the power variation range monitoring value of the i-th part is less than the power variation range of the previous i-1 parts. If so, a tool breakage alarm is triggered and the machine is stopped.

[0015] Furthermore, S1 specifically refers to:

[0016] S101: During the process of compiling CNC programs for part machining, each CNC program is divided into segments according to the tool advance and retraction during the post-processing process, and each monitoring segment is numbered sequentially.

[0017] S102: Before executing the m-th item of the CNC program for the first part, collect the maximum and minimum spindle power values ​​during idle rotation at the corresponding speed of the CNC program, and record them as follows:

[0018]

[0019]

[0020] Where P represents the power value, the upper left corner mark 1 indicates the first part, the upper right corner mark m indicates the mth CNC program, the lower right corner mark k indicates the spindle idling, MAX indicates the maximum value, and MIN indicates the maximum value.

[0021] S103: Calculate the spindle power change value of the m-th CNC program when the spindle is idling, and record it as:

[0022]

[0023] Where W represents the power change magnitude;

[0024] S104: Enlarge the original calculated value, set the monitoring value for the change in processing power of the first part, and record it as:

[0025]

[0026] Wherein, the subscript f represents the amplitude of the amplification power change, and e represents the amplification factor;

[0027] S105: During part processing, the maximum and minimum power values ​​for each monitoring segment are collected and recorded as follows:

[0028]

[0029]

[0030] Wherein, the subscript n represents the nth monitoring segment divided by the mth CNC program;

[0031] S106: Calculate the change in machining power of the first part in the nth monitoring segment under the mth CNC program, and denote it as:

[0032]

[0033] S107: Compare the value of the change in part processing power in the nth monitoring segment under the mth CNC program with the value of the change in part processing power monitoring. If the former is less than the latter for 7 consecutive monitoring segments, then determine that the tool has broken in the (n+6)th monitoring segment. Otherwise, return to step S105.

[0034] S108: Tool breakage alarm, machine tool stops running.

[0035] Furthermore, the size comparison relationship in S107 is specifically as follows:

[0036]

[0037] Furthermore, S2 specifically refers to:

[0038] S201: Before executing the m-th item of the CNC program for the second part, collect the maximum and minimum spindle power values ​​during idle rotation at the corresponding speed of the CNC program, and record them as follows:

[0039]

[0040]

[0041] The number 2 in the upper left corner indicates the second item;

[0042] S202: Calculate the spindle power change value of the m-th CNC program when the spindle is idling, and record it as:

[0043]

[0044] S203: Superimpose the spindle idling power variation value of the first part, and amplify the original calculated value on this basis to set the monitoring value for the machining power variation of the second part, denoted as:

[0045]

[0046] S204: During part processing, acquire the maximum and minimum power values ​​for each monitoring segment, and record them as follows:

[0047]

[0048]

[0049] S205: Calculate the change in machining power of the second part in the nth monitoring segment under the mth CNC program, denoted as:

[0050]

[0051] S206: Compare the part processing power change amplitude value and the part processing power change amplitude monitoring value of the second part in the nth monitoring segment under the mth CNC program. If the former is less than the latter, and the latter is less than the power change amplitude value corresponding to the processing (normal processing) of the first part, and this continues for 3 monitoring segments, then it is determined that the tool has broken in the n+2th monitoring segment. Otherwise, return to step S204.

[0052] S207: Tool breakage alarm, machine tool stops running.

[0053] Furthermore, the size comparison relationship in S206 is specifically as follows:

[0054]

[0055] Furthermore, S3 specifically refers to:

[0056] S301: Before executing the CNC program for the mth item of the 3rd part, collect the maximum and minimum spindle power values ​​during idle rotation at the corresponding speed of the CNC program, and record them as follows:

[0057]

[0058]

[0059] The number 3 in the upper left corner indicates the third item;

[0060] S302: Calculate the spindle power change value of the m-th CNC program when the spindle is idling, and record it as:

[0061]

[0062] S303: Superimpose the spindle idling power variation values ​​of the first two parts, and amplify the original calculated value to set the monitoring value for the machining power variation of the third part, denoted as:

[0063]

[0064] S304: During part processing, acquire the maximum and minimum power values ​​for each monitoring segment, and record them as follows:

[0065]

[0066]

[0067] S305: Calculate the change in machining power of the third part in the nth monitoring segment under the mth CNC program, denoted as:

[0068]

[0069] S306: Compare the part processing power change amplitude value and the part processing power change amplitude monitoring value of the third part in the nth monitoring segment under the mth CNC program. If the former is less than the latter, and the latter is less than the power change amplitude value corresponding to the processing of the first and second parts, and this continues for 2 monitoring segments, then it is determined that the tool has broken in the n+1th monitoring segment. Otherwise, return to step S304.

[0070] S307: Tool breakage alarm, machine tool stops running.

[0071] Furthermore, the size comparison relationship in S306 is specifically as follows:

[0072]

[0073] Furthermore, S4 specifically includes:

[0074] S401: When the i-th part is being processed, the maximum and minimum power values ​​for each monitoring segment are obtained and recorded as follows:

[0075]

[0076]

[0077] S402: Calculate the change in machining power of the i-th part in the n-th monitoring segment under the m-th CNC program, denoted as:

[0078]

[0079] S403: After the third part is processed, the power change amplitude monitoring value of the i-th part is adopted from the power change amplitude monitoring value of the third part. The power change amplitude value of the i-th part in the nth monitoring segment under the m-th CNC program is compared with the power change amplitude monitoring value of the i-th part. If the former is less than the latter, and the latter is less than the power change amplitude value corresponding to the processing of the first i-1 parts, then it is determined that the tool has broken in the nth monitoring segment. Otherwise, return to step S401.

[0080] S404: Tool breakage alarm, machine tool stops running.

[0081] Furthermore, the size comparison relationship in S403 is specifically as follows:

[0082]

[0083] The beneficial effects of this invention are as follows:

[0084] 1. This method also implements tool breakage monitoring for the first piece machining of structural components, avoiding the quality risks caused by risky machining due to a lack of monitoring data during the first piece machining. Structural components made of difficult-to-machine materials not only have expensive raw material prices but also extremely high machining costs. Therefore, it is not feasible to use the first part for trial and error machining and to create a monitoring database. This method designs a monitoring value for the machining power variation of the first part at the corresponding spindle speed in the CNC program before the first part is formally machined. It also designs a strategy that triggers an alarm only if the power variation value is less than the monitoring value for seven consecutive monitoring segments. This fully considers the situation where there are small machining allowance segments during the machining of structural components, which may lead to insignificant spindle power changes. The probability of insignificant power changes for seven consecutive times is extremely low, ensuring the effectiveness of tool breakage monitoring during the first piece machining.

[0085] 2. This method sets an amplification factor for the power variation of the spindle idling based on the number of times the part is processed. This amplifies the monitoring value for fewer processing cycles, avoiding false alarms caused by inaccurate monitoring data. The fewer the processing cycles, the greater the impact of abnormal data on the monitoring process. Appropriately amplifying the power variation of the spindle idling based on the number of part processing cycles can effectively avoid the influence of abnormal data and reduce the false alarm rate.

[0086] 3. This method comprehensively considers both current and previous processing data during the machining of non-first-piece parts, effectively improving monitoring accuracy. During the machining of non-first-piece parts, it compares not only the current power variation amplitude with the monitored power variation amplitude, but also the monitored power variation amplitude with the corresponding power variation amplitude during previous part machining. Tool breakage monitoring and judgment are considered both horizontally and vertically, effectively improving monitoring accuracy. Attached Figure Description

[0087] Figure 1 This is a schematic diagram of the tool breakage monitoring strategy for the first part.

[0088] Figure 2 This is a schematic diagram of the tool breakage monitoring strategy for the second part.

[0089] Figure 3 This is a schematic diagram of the tool breakage monitoring strategy for the third part.

[0090] Figure 4 This is a schematic diagram of the tool breakage monitoring strategy for the i-th (i≥4) part. Detailed Implementation

[0091] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are for explaining the invention and not for limiting it. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0092] The specific implementation method of the present invention will be described below with reference to the accompanying drawings and examples. The present invention is not limited to this embodiment.

[0093] Example 1

[0094] A method for identifying tool breakage based on the variation amplitude of machine tool spindle power includes the following steps:

[0095] S1: Tool breakage monitoring strategy for the first part:

[0096] The CNC program is segmented. When the spindle is idling, the maximum and minimum power values ​​are obtained, the spindle idling power variation range is calculated, and the power variation range monitoring value for the first part is set. When the part is being machined, the maximum and minimum power values ​​are obtained; the power variation range for the first part is calculated; it is observed whether the power variation range for the first part is less than the power variation range monitoring value for the first part for 7 consecutive monitoring segments. If so, a tool breakage alarm is triggered and the machine is stopped.

[0097] S2: Tool breakage monitoring strategy for the second part:

[0098] When the spindle is idling, acquire the maximum and minimum power values; calculate the spindle idling power variation range; superimpose the spindle idling power variation range value for the first part, and set the power variation range monitoring value for the second part; when the part is being processed, acquire the maximum and minimum power values; calculate the power variation range value for the second part; observe whether the power variation range value for the second part is less than the power variation range monitoring value for the second part for three consecutive monitoring segments, and whether the power variation range monitoring value for the second part is less than the power variation range value for the first part. If so, trigger a tool breakage alarm and stop the machine.

[0099] S3: Tool breakage monitoring strategy for the third part:

[0100] When the spindle is idling, acquire the maximum and minimum power values; calculate the spindle idling power variation range; superimpose the spindle idling power variation range value for the second part, and set the power variation range monitoring value for the third part; when the part is being processed, acquire the maximum and minimum power values; calculate the power variation range value for the third part; observe whether the power variation range value for the third part is lower than the power variation range monitoring value for the third part for two consecutive monitoring segments, and whether the power variation range monitoring value for the third part is lower than the power variation range values ​​for the first and second parts. If so, trigger a tool breakage alarm and stop the machine.

[0101] S4: Tool breakage monitoring strategy for the i-th part, i≥4:

[0102] During part processing, the maximum and minimum power values ​​are obtained; the power variation range of the i-th part is calculated; it is observed whether the power variation range of the i-th part is less than the power variation range monitoring value of the i-th part, and the power variation range monitoring value of the i-th part is less than the power variation range of the previous i-1 parts. If so, a tool breakage alarm is triggered and the machine is stopped.

[0103] Furthermore, S1 specifically refers to:

[0104] S101: During the process of compiling CNC programs for part machining, each CNC program is divided into segments according to the tool advance and retraction during the post-processing process, and each monitoring segment is numbered sequentially.

[0105] S102: Before machining the m-th CNC program for the first part (under the same CNC program, the spindle speed remains constant), collect the maximum and minimum spindle power values ​​during idle operation (lasting 2 minutes) at the corresponding speed of the CNC program, and record them as follows:

[0106]

[0107]

[0108] Where P represents the power value, the upper left corner mark 1 indicates the first part, the upper right corner mark m indicates the mth CNC program, the lower right corner mark k indicates the spindle idling, MAX indicates the maximum value, and MIN indicates the maximum value.

[0109] S103: Calculate the spindle power change value of the m-th CNC program when the spindle is idling, and record it as:

[0110]

[0111] Where W represents the power change magnitude;

[0112] S104: Considering that occasional uncertainties in a single processing operation can lead to inaccurate power variation values, the original calculated value needs to be increased to avoid frequent false alarms. The power variation monitoring value for the processing of the first part is set as follows:

[0113]

[0114] Wherein, the subscript f represents the amplitude of the amplification power change, and e represents the amplification factor;

[0115] S105: During part processing, the maximum and minimum power values ​​for each monitoring segment are collected and recorded as follows:

[0116]

[0117]

[0118] Wherein, the subscript n represents the nth monitoring segment divided by the mth CNC program;

[0119] S106: Calculate the change in machining power of the first part in the nth monitoring segment under the mth CNC program, and denote it as:

[0120]

[0121] S107: Compare the value of the change in part processing power in the nth monitoring segment under the mth CNC program with the value of the change in part processing power monitoring. If the former is less than the latter for 7 consecutive monitoring segments, then determine that the tool has broken in the (n+6)th monitoring segment. Otherwise, return to step S105.

[0122] S108: Tool breakage alarm, machine tool stops running.

[0123] Furthermore, the size comparison relationship in S107 is specifically as follows:

[0124]

[0125] Furthermore, S2 specifically refers to:

[0126] S201: Before machining the m-th item of the CNC program for the second part (under the same CNC program, the spindle speed remains constant), collect the maximum and minimum spindle power values ​​during idle operation (lasting 2 minutes) at the corresponding speed of the CNC program, and record them as follows:

[0127]

[0128]

[0129] The number 2 in the upper left corner indicates the second item;

[0130] S202: Calculate the spindle power change value of the m-th CNC program when the spindle is idling, and record it as:

[0131]

[0132] S203: Considering that the accidental uncertainties in a single machining operation may lead to inaccurate power variation values, it is necessary to superimpose the power variation value of the first spindle idle operation, and amplify the original calculated value on top of it to avoid frequent false alarms. The power variation monitoring value for the second part is set as follows:

[0133]

[0134] S204: During part processing, acquire the maximum and minimum power values ​​for each monitoring segment, and record them as follows:

[0135]

[0136]

[0137] S205: Calculate the change in machining power of the second part in the nth monitoring segment under the mth CNC program, denoted as:

[0138]

[0139] S206: Compare the part processing power change amplitude value and the part processing power change amplitude monitoring value of the second part in the nth monitoring segment under the mth CNC program. If the former is less than the latter, and the latter is less than the power change amplitude value corresponding to the processing (normal processing) of the first part, and this continues for 3 monitoring segments, then it is determined that the tool has broken in the n+2th monitoring segment. Otherwise, return to step S204.

[0140] S207: Tool breakage alarm, machine tool stops running.

[0141] Furthermore, the size comparison relationship in S206 is specifically as follows:

[0142]

[0143] Furthermore, S3 specifically refers to:

[0144] S301: Before machining the m-th item of the CNC program for the 3rd part (under the same CNC program, the spindle speed remains constant), collect the maximum and minimum spindle power values ​​during idle operation (lasting 2 minutes) at the corresponding speed of the CNC program, and record them as follows:

[0145]

[0146]

[0147] The number 3 in the upper left corner indicates the third item;

[0148] S302: Calculate the spindle power change value of the m-th CNC program when the spindle is idling, and record it as:

[0149]

[0150] S303: Considering that occasional uncertainties in a single machining operation can lead to inaccurate power variation values, it is necessary to superimpose the power variation values ​​of the first two spindle idle cycles and amplify the original calculated value to avoid frequent false alarms. The power variation monitoring value for the third part is set as follows:

[0151]

[0152] S304: During part processing, acquire the maximum and minimum power values ​​for each monitoring segment, and record them as follows:

[0153]

[0154]

[0155] S305: Calculate the change in machining power of the third part in the nth monitoring segment under the mth CNC program, denoted as:

[0156]

[0157] S306: Compare the part processing power change amplitude value and the part processing power change amplitude monitoring value of the third part in the nth monitoring segment under the mth CNC program. If the former is less than the latter, and the latter is less than the power change amplitude value corresponding to the processing (normal processing) of the first and second parts, and this continues for 2 monitoring segments, then it is determined that the tool has broken in the n+1th monitoring segment. Otherwise, return to step S304.

[0158] S307: Tool breakage alarm, machine tool stops running.

[0159] Furthermore, the size comparison relationship in S306 is specifically as follows:

[0160]

[0161] Furthermore, S4 specifically includes:

[0162] S401: When the i-th part is being processed, the maximum and minimum power values ​​for each monitoring segment are obtained and recorded as follows:

[0163]

[0164]

[0165] S402: Calculate the change in machining power of the i-th part in the n-th monitoring segment under the m-th CNC program, denoted as:

[0166]

[0167] S403: After the third part has been processed, the monitoring value of the processing power change amplitude has become relatively stable. Therefore, the monitoring value of the processing power change amplitude of the i-th part is adopted from the monitoring value of the processing power change amplitude of the third part. The processing power change amplitude value of the i-th part in the nth monitoring segment under the m-th CNC program is compared with the size of the processing power change amplitude monitoring value. If the former is less than the latter, and the latter is less than the power change amplitude value corresponding to the processing of the first i-1 parts (normal processing), then it is determined that the tool has broken in the nth monitoring segment. Otherwise, return to step S401.

[0168] S404: Tool breakage alarm, machine tool stops running.

[0169] Furthermore, the size comparison relationship in S403 is specifically as follows:

[0170]

[0171] Example 2

[0172] Taking the processing of titanium alloy structural parts as an example, the specific implementation content and steps are as follows:

[0173] S1: Tool breakage monitoring strategy for the first part

[0174] S101: During the process of compiling CNC programs for part machining, each CNC program is divided into segments according to the tool advance and retraction during the post-processing stage, and each monitoring segment is numbered sequentially.

[0175] S102: Before machining the 5th item of the CNC program for the first part (under the same CNC program, the spindle speed remains constant), collect the maximum and minimum spindle power values ​​during idle operation (lasting 2 minutes) at the corresponding speed of the CNC program:

[0176]

[0177]

[0178] S103: Calculate the spindle power change value during spindle idling in the 5th CNC program, and record it as:

[0179]

[0180] S104: Considering the occasional uncertainties in a single machining operation (mainly the influence of the machine tool's own operating status), which may lead to inaccurate power variation values, the original calculated value needs to be amplified to avoid frequent false alarms, especially when machining titanium alloy structural parts. 1 With e set to 1.5, the monitoring value for the variation in processing power of the first part is:

[0181]

[0182] S105: During part machining, collect the maximum and minimum power values ​​of each monitoring segment of the 5th CNC program, which are as follows:

[0183]

[0184]

[0185] S106: Calculate the machining power variation value of the first part in each monitoring segment under the 5th CNC program, as follows:

[0186]

[0187]

[0188] S107: Compare the value of the change in machining power of the first part with the value of the monitored change in machining power of the first part in each monitoring segment under the fifth CNC program, as follows:

[0189]

[0190]

[0191] Although it appeared in the 8th monitoring segment But in the 9th monitoring segment Therefore, the suspected abnormal data only occurred once and was not determined to be a tool breakage. However, starting from the 10th monitoring segment, The monitoring lasted for 7 segments, namely:

[0192]

[0193] The tool is determined to be broken in the 16th monitoring segment.

[0194] S108: Tool breakage alarm, machine tool stops running.

[0195] S2: Tool breakage monitoring strategy for the second part

[0196] S201: Before machining the 5th item of the CNC program for the 2nd part (under the same CNC program, the spindle speed remains constant), collect the maximum and minimum spindle power values ​​during idling (lasting 2 minutes) at the corresponding speed of the CNC program, and record them as follows:

[0197]

[0198]

[0199] S202: Calculate the spindle power change value in the 5th CNC program when the spindle is idling:

[0200]

[0201] S203: Considering that the accidental uncertainties in a single machining operation may lead to inaccurate power variation values, it is necessary to superimpose the power variation value of the first spindle idle operation and amplify the original calculated value on top of it to avoid frequent false alarms, especially when machining titanium alloy structural parts. 2 With e set to 1.35, the monitored value for the change in processing power of the second part is calculated as follows:

[0202]

[0203] S204: When the part is being machined, obtain the maximum and minimum power values ​​for each monitoring segment in the 5th CNC program, as follows:

[0204]

[0205] S205: Calculate the machining power variation value of the second part in each monitoring segment under the fifth CNC program, as follows:

[0206]

[0207]

[0208] S206: Compare the changes in machining power and the monitored values ​​of machining power changes for the second part in each monitoring segment under the fifth CNC program.

[0209]

[0210] Starting from the 5th monitoring segment, The monitoring lasted for three segments, and all three segments met the requirements. Right now:

[0211]

[0212] The tool is determined to be broken in the 7th monitoring segment.

[0213] S207: Tool breakage alarm, machine tool stops running.

[0214] S3: Tool breakage monitoring strategy for the third part

[0215] S301: Before machining the 5th item of the CNC program for the 3rd part (under the same CNC program, the spindle speed remains constant), collect the maximum and minimum spindle power values ​​during idling (lasting 2 minutes) at the corresponding speed of the CNC program, and record them as follows:

[0216]

[0217]

[0218] S302: Calculate the spindle power change value during spindle idling in the fifth CNC program, and record it as:

[0219]

[0220] S303: Considering that the accidental uncertainties in a single machining operation can lead to inaccurate power variation values, it is necessary to superimpose the power variation values ​​of the first two spindle idle cycles and amplify the original calculated value to avoid frequent false alarms, especially when machining titanium alloy structural parts. 3 With e set to 1.25, the monitored value for the change in processing power of the third part is calculated as follows:

[0221]

[0222] S304: When machining a part, obtain the maximum and minimum power values ​​for each monitoring segment in the 5th CNC program, as follows:

[0223]

[0224] S305: Calculate the machining power variation value of the 3rd part in each monitoring segment under the 5th CNC program, as follows:

[0225]

[0226]

[0227] S306: Compare the changes in machining power of the third part under the fifth CNC program, and the magnitudes of the changes in machining power monitoring values ​​for each monitoring segment, as follows:

[0228]

[0229] Starting from the third monitoring segment, Two monitoring segments were conducted consecutively, and both segments met the requirements. and Right now:

[0230]

[0231] The tool is then determined to be broken in the third monitoring segment.

[0232] S307: Tool breakage alarm, machine tool stops running.

[0233] S4: Tool breakage monitoring strategy for the 4th part

[0234] S401: When the part is being machined, obtain the maximum and minimum power values ​​for each monitoring segment in the 5th CNC program, as follows:

[0235]

[0236] S402: Calculate the machining power variation value of the 4th part in each monitoring segment under the 5th CNC program, as follows:

[0237]

[0238] S403: After machining the third part, the monitored value of the machining power variation has become relatively stable. Therefore, the monitored value of the machining power variation for the fourth part will be the same as that for the third part. The monitored values ​​of the machining power variation for each monitoring segment of the fourth part under the fifth CNC program are compared as follows:

[0239]

[0240] In the second monitoring segment, And satisfy and and Right now:

[0241]

[0242] The tool is then determined to be broken in the second monitoring segment.

[0243] S404: Tool breakage alarm, machine tool stops running.

[0244] The processing strategy for the i-th (i≥5) part is the same as that for the 4th part, so it will not be repeated here.

[0245] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for identifying tool breakage based on the variation amplitude of machine tool spindle power, characterized in that: Includes the following steps: S1: Tool breakage monitoring strategy for the first part: The CNC program is segmented. When the spindle is idling, the maximum and minimum power values ​​are obtained, the spindle idling power variation range is calculated, and the power variation range monitoring value for the first part is set. When the part is being machined, the maximum and minimum power values ​​are obtained; the power variation range for the first part is calculated; it is observed whether the power variation range for the first part is less than the power variation range monitoring value for the first part for 7 consecutive monitoring segments. If so, a tool breakage alarm is triggered and the machine is stopped. Specifically, S1 is: S101: During the process of compiling CNC programs for part machining, each CNC program is divided into segments according to the tool advance and retraction during the post-processing process, and each monitoring segment is numbered sequentially. S102: In the first part, m Before executing the CNC program, the maximum and minimum power values ​​of the spindle during idle operation at the corresponding speed of the CNC program are collected and recorded as follows: in, P The power value is indicated by a superscript number 1, which indicates the first component, and a superscript number 1. m Indicates the first m Item CNC program, subscript k This indicates that the spindle is idling. MAX Indicates the maximum value. MIN Indicates the maximum value; S103: Calculate the... m The value of the spindle power change during spindle idling in the CNC program is recorded as: in, W This indicates the magnitude of the power change; S104: Enlarge the original calculated value, set the monitoring value for the change in processing power of the first part, and record it as: Subscript f This indicates the magnitude of the change in amplification power. e Indicates the magnification factor; S105: During part processing, the maximum and minimum power values ​​for each monitoring segment are collected and recorded as follows: Subscript n Indicates the first m The first item of the CNC program n One monitoring segment; S106: Calculate the first part in the... m Under the CNC program, the first n The variation range of processing power in each monitoring segment is denoted as: S107: Compare the first part in the... m Under the CNC program, the first n If the change in part processing power in each monitoring segment is less than the change in part processing power for seven consecutive monitoring segments, then in the [number]th monitoring segment... n+ The 6 monitoring segments determine whether the tool has broken. If not, return to step S105. S108: Tool breakage alarm, machine tool stops running; S2: Tool breakage monitoring strategy for the second part: When the spindle is idling, acquire the maximum and minimum power values; calculate the spindle idling power variation range; superimpose the spindle idling power variation range value for the first part, and set the power variation range monitoring value for the second part; when the part is being processed, acquire the maximum and minimum power values; calculate the power variation range value for the second part; observe whether the power variation range value for the second part is less than the power variation range monitoring value for the second part for three consecutive monitoring segments, and whether the power variation range monitoring value for the second part is less than the power variation range value for the first part. If so, trigger a tool breakage alarm and stop the machine. S3: Tool breakage monitoring strategy for the third part: When the spindle is idling, acquire the maximum and minimum power values; calculate the spindle idling power variation range; superimpose the spindle idling power variation range value for the second part, and set the power variation range monitoring value for the third part; when the part is being processed, acquire the maximum and minimum power values; calculate the power variation range value for the third part; observe whether the power variation range value for the third part is lower than the power variation range monitoring value for the third part for two consecutive monitoring segments, and whether the power variation range monitoring value for the third part is lower than the power variation range values ​​for the first and second parts. If so, trigger a tool breakage alarm and stop the machine. S4: Tool breakage monitoring strategy for the i-th part, i≥4: During part processing, the maximum and minimum power values ​​are obtained; the power variation range of the i-th part is calculated; it is observed whether the power variation range of the i-th part is less than the power variation range monitoring value of the i-th part, and the power variation range monitoring value of the i-th part is less than the power variation range of the previous i-1 parts. If so, a tool breakage alarm is triggered and the machine is stopped.

2. The tool breakage identification method based on the variation amplitude of machine tool spindle power according to claim 1, characterized in that: The size comparison relationship in S107 is specifically as follows: 。 3. The tool breakage identification method based on the variation amplitude of machine tool spindle power according to claim 1, characterized in that: Specifically, S2 is: S201: In the second part, m Before executing the CNC program, the maximum and minimum power values ​​of the spindle during idle operation at the corresponding speed of the CNC program are collected and recorded as follows: Among them, among them, P This indicates the power value; the superscript 2 indicates the second component; the superscript 0 indicates the power value. m Indicates the first m Item CNC program, subscript k This indicates that the spindle is idling. MAX Indicates the maximum value. MIN Indicates the maximum value; S202: Calculate the... m The value of the spindle power change during spindle idling in the CNC program is recorded as: in, W This indicates the magnitude of the power change; S203: Superimpose the spindle idling power variation value of the first part, and amplify the original calculated value on this basis to set the monitoring value for the machining power variation of the second part, denoted as: Subscript f This indicates the magnitude of the change in amplification power. e Indicates the magnification factor; S204: During part processing, acquire the maximum and minimum power values ​​for each monitoring segment, and record them as follows: Subscript n Indicates the first m The first item of the CNC program n One monitoring segment; S205: Calculate the second part in the... m Under the CNC program, the first n The variation range of processing power in each monitoring segment is denoted as: S206: Compare the second part in the... m Under the CNC program, the first n The monitoring values ​​for the change in part processing power and the monitoring value for the change in part processing power are used for each monitoring segment. If the former is less than the latter, and the latter is less than the power change value corresponding to the processing of the first part, and this continues for 3 monitoring segments, Then in the n+ Two monitoring segments determine whether the tool has broken. If not, return to step S204. S207: Tool breakage alarm, machine tool stops running.

4. The tool breakage identification method based on the variation amplitude of machine tool spindle power according to claim 3, characterized in that: The size comparison relationship in S206 is specifically as follows: 。 5. The tool breakage identification method based on the variation amplitude of machine tool spindle power according to claim 1, characterized in that: Specifically, S3 is: S301: In the 3rd part, m Before executing the CNC program, the maximum and minimum power values ​​of the spindle during idle operation at the corresponding speed of the CNC program are collected and recorded as follows: in, P This indicates the power value; the superscript 3 indicates the third component; the superscript 4 indicates the power value. m Indicates the first m Item CNC program, subscript k This indicates that the spindle is idling. MAX Indicates the maximum value. MIN Indicates the maximum value; S302: Calculate the... m The value of the spindle power change during spindle idling in the CNC program is recorded as: in, W This indicates the magnitude of the power change; S303: Superimpose the spindle idling power variation values ​​of the first two parts, and amplify the original calculated value to set the monitoring value for the machining power variation of the third part, denoted as: Subscript f This indicates the magnitude of the change in amplification power. e Indicates the magnification factor; S304: During part processing, acquire the maximum and minimum power values ​​for each monitoring segment, and record them as follows: Subscript n Indicates the first m The first item of the CNC program n One monitoring segment; S305: Calculate the third part in the... m Under the CNC program, the first n The variation range of processing power in each monitoring segment is denoted as: S306: Compare the third part in the... m Under the CNC program, the first n The monitoring values ​​for the power variation amplitude of the parts in each monitoring segment and the monitoring value for the power variation amplitude of the parts are considered. If the former is less than the latter, and the latter is less than the power variation amplitude corresponding to the processing of the first and second parts, and this continues for two monitoring segments, then in the [missing information] segment... n+ One monitoring segment determines that the tool has broken; if not, it returns to step S304. S307: Tool breakage alarm, machine tool stops running.

6. The tool breakage identification method based on the variation amplitude of machine tool spindle power according to claim 5, characterized in that: The size comparison relationship in S306 is specifically as follows: 。 7. The tool breakage identification method based on the variation amplitude of machine tool spindle power according to claim 1, characterized in that: Specifically, S4 is: S401: When the i-th part is being processed, the maximum and minimum power values ​​for each monitoring segment are obtained and recorded as follows: in, P The power value is indicated by the superscript 'i' indicating the i-th component, and the superscript 'i' indicating the power value. m Indicates the first m Item CNC program, subscript k This indicates that the spindle is idling. MAX Indicates the maximum value. MIN Indicates the maximum value; S402: Calculate the i-th part in the... m Under the CNC program, the first n The variation range of processing power in each monitoring segment is denoted as: in, W This indicates the magnitude of the power change; S403: After the third part is machined, the monitoring value of the machining power variation of the i-th part is adopted from the monitoring value of the machining power variation of the third part, and compared with the monitoring value of the machining power variation of the i-th part in the third part. m Under the CNC program, the first n The monitoring segment's part processing power change amplitude value and the part processing power change amplitude monitoring value are used to determine the order of events. If the former is less than the latter, and the latter is less than the power change amplitude value corresponding to the processing of the first i-1 parts, then in the i-th segment... n If the monitoring segment determines that the tool has broken, it returns to step S401 if not. S404: Tool breakage alarm, machine tool stops running.

8. The tool breakage identification method based on the variation amplitude of machine tool spindle power according to claim 7, characterized in that: The size comparison relationship in S403 is specifically as follows: 。

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