Automatic feeding boring method and equipment for RV reducer planet carrier

Abstract

The application relates to the technical field of machine tool boring, in particular to an automatic feeding boring machining method and equipment for a RV reducer planet carrier. The method comprises the following steps: acquiring spindle vibration data and spindle load power in a machining process; determining a cutting state index by linkage judgment according to the spindle vibration data and the spindle load power, and adaptively adjusting a feeding rate based on the cutting state index to control a cutting heat generation rate; acquiring a tool wear state coefficient according to vibration trend deviation and load trend deviation in each machining, and adjusting a boring tool U-axis extension amount based on the tool wear state coefficient; taking a temperature difference between a current machining hole position and a reference hole position as input, taking the tool wear state coefficient as a working condition correction factor, calculating a total compensation coefficient, and determining actual machining coordinates to perform boring machining; and performing online detection after machining to verify hole system position accuracy, and forming a data closed loop to optimize subsequent machining parameters, thereby improving first pass yield and machining efficiency.

Description

Technical Field

[0001] This application belongs to the field of machine tool boring technology, specifically relating to an automatic feed boring method and equipment for planetary carriers of RV reducers. Background Technology

[0002] The planetary carrier of an RV reducer has a central bearing bore and multiple evenly distributed planetary gear shaft bores, requiring extremely high positional accuracy (typically at the micrometer level). In automated feed boring operations, all holes must be machined sequentially under the same clamping. The heat generated during cutting causes uneven thermal expansion between the workpiece and the machine spindle, resulting in holes machined earlier and later operating at different temperature baselines, leading to out-of-tolerance positional accuracy after cooling. Simultaneously, cutting vibrations caused by uneven blank allowance and dimensional drift due to progressive tool wear further exacerbate the uncertainty of thermal deformation. Existing machining methods typically employ fixed cutting parameters and constant cooling measures, failing to adaptively adjust to changing operating conditions during machining, resulting in decreased machining accuracy, yield, and efficiency. Summary of the Invention

[0003] To address the aforementioned issues, this application provides an automatic feed boring method and equipment for planetary carriers of RV reducers.

[0004] According to a first aspect of the embodiments of this application, an automatic feed boring method for a planetary carrier of an RV reducer is provided, the method comprising: Acquire spindle vibration data and spindle load power during the machining process; The cutting state index is determined by linking the spindle vibration data and the spindle load power, and the feed rate is adaptively adjusted based on the cutting state index to control the rate of cutting heat generation. Based on the vibration trend offset and load trend offset in each machining operation, the tool wear state coefficient is obtained, and the U-axis extension of the boring tool is adjusted based on the tool wear state coefficient. Using the temperature difference between the current machining hole position and the reference hole position as input, and the tool wear state coefficient as the working condition correction factor, the total compensation coefficient is calculated and the actual machining coordinates are determined to perform boring machining. After machining is completed, online inspection is performed to verify the positional accuracy of the hole system and to form a data closed loop to optimize subsequent machining parameters.

[0005] In one embodiment, the spindle vibration data includes effective vibration values. The step of determining a cutting state index based on the spindle vibration data and the spindle load power, and adaptively adjusting the feed rate based on the cutting state index, includes: Obtain the warning threshold for vibration and the load safety threshold for load. The vibration exceedance ratio is obtained by the ratio of the effective vibration value to the warning threshold of the vibration dimension. The overload ratio is obtained based on the ratio of the spindle load power to the load safety threshold. The cutting state index is obtained based on the vibration over-limit ratio and the load over-limit ratio, and the graded feed rate adjustment is performed according to the interval of the cutting state index.

[0006] In one embodiment, obtaining the cutting condition index based on the vibration over-limit ratio and the load over-limit ratio includes: Obtain the current sampling period count and the preset sampling count threshold; The cutting state index is obtained based on the number of sampling cycles, the sampling count threshold, the vibration over-limit ratio, and the load over-limit ratio.

[0007] In one embodiment, the step of performing graded feed rate adjustment based on the range of the cutting state index includes: When the cutting state index is less than or equal to the first preset threshold and the load over-limit ratio is less than or equal to 1, the feed rate is set to a high-efficiency feed rate. When the cutting state index is greater than the first preset threshold and less than or equal to the second preset threshold, the feed rate is reduced to the standard feed rate. When the cutting state index is greater than the second preset threshold, the feed rate is forcibly reduced to the safe feed rate, the high-efficiency feed rate is greater than the standard feed rate, and the standard feed rate is greater than the safe feed rate.

[0008] In one embodiment, the step of performing graded feed rate adjustment based on the range of the cutting state index further includes: When the spindle load power reaches the load warning threshold of the load dimension, regardless of the value of the cutting state index, the feed rate is forcibly reduced to the safe feed rate, and the load warning threshold is greater than the load safety threshold. When the cutting state index falls below the first preset threshold and the load over-limit ratio is less than or equal to 1 and is maintained for a continuous sampling count threshold sampling period, the feed rate is gradually restored to the high-efficiency feed rate.

[0009] In one embodiment, the step of obtaining a tool wear state coefficient based on the vibration trend offset and load trend offset in each machining operation, and adjusting the U-axis extension of the boring tool based on the tool wear state coefficient, includes: When machining the first hole in the new tool state, obtain the first average vibration value and the first average load value during the smooth cutting stage; After machining the target hole, the second average vibration value and the second average load value during the smooth cutting phase of the target hole machining process are obtained, where the target hole is any machined hole after the first hole. The vibration trend deviation ratio is determined based on the ratio of the second vibration mean to the first vibration mean, and the load trend deviation ratio is determined based on the ratio of the second load mean to the first load mean. Based on the vibration trend offset ratio and the load trend offset ratio, the tool wear trend coefficient is obtained, and the tool wear trend coefficient is directly mapped to the tool wear state coefficient; The tool wear compensation amount is obtained based on the tool wear state coefficient, and the U-axis extension of the boring tool is adjusted based on the tool wear compensation amount.

[0010] In one embodiment, obtaining the tool wear trend coefficient includes: Obtain the cumulative number of processed holes and the preset reference number of holes; The tool wear trend coefficient is obtained based on the cumulative value, the number of reference holes, the vibration trend offset ratio, and the load trend offset ratio.

[0011] In one implementation, calculating the total compensation coefficient and determining the actual machining coordinates to perform boring includes: The workpiece temperature at the moment the first hole is completed is used as the temperature reference, and the tool wear state coefficient at the moment the first hole is completed is used as the tool working condition reference. The difference between the workpiece temperature at the current hole position and the temperature reference is obtained, as well as the tool wear coefficient at the current hole position. The thermal expansion basic compensation coefficient is calculated based on the difference between the workpiece temperature at the current hole position and the temperature reference. The relative change factor is calculated based on the ratio of the tool wear state coefficient when machining the current hole position to the tool working condition reference, and the product of the thermal expansion basic compensation coefficient and the relative change factor is used as the total compensation coefficient. The actual machining coordinates of each hole are calculated based on the total compensation coefficient and the preset basic compensation reference value, and the actual machining coordinates are written into the interpolation command of the CNC system to perform boring.

[0012] In one embodiment, after the machining is completed, online inspection is performed to verify the positional accuracy of the hole system and form a data closed loop, including: After all holes have been machined, when the workpiece temperature drops back to within the sum of the initial temperature and the cooling completion threshold, measure the actual coordinate position of each hole and calculate the positional deviation. If the positional deviation is within the preset tolerance range, the temperature rise curve, compensation record and test results of this processing will be written into the historical database. If the positional deviation exceeds the preset tolerance range, the deviation data is compared and analyzed with historical data. If the deviation shows a systematic trend, the basic compensation benchmark value is adjusted to form a closed-loop optimization of processing-compensation-detection-update.

[0013] According to a second aspect of the embodiments of this application, an automatic feed boring machine for a planetary carrier of an RV reducer is provided, the machine including a controller, the controller comprising: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the steps of the method of any one of the first aspects.

[0014] The embodiments of this application have the following beneficial effects: acquiring spindle vibration data and spindle load power during the machining process; determining the cutting state index by linkage judgment based on the spindle vibration data and spindle load power, and adaptively adjusting the feed rate based on the cutting state index to control the rate of cutting heat generation; acquiring the tool wear state coefficient based on the vibration trend deviation and load trend deviation in each machining operation, and adjusting the U-axis extension of the boring tool based on the tool wear state coefficient; calculating the total compensation coefficient and determining the actual machining coordinates to perform boring machining by using the temperature difference between the current machining hole position and the reference hole position as input and the tool wear state coefficient as the working condition correction factor; performing online detection after machining to verify the hole system position accuracy and forming a data closed loop to optimize subsequent machining parameters. The embodiments of this application achieve adaptive protection of the hole system position accuracy by controlling the heat source through vibration and load linkage, combined with wear assessment and temperature difference compensation, effectively improving the first-pass yield and machining efficiency.

[0015] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating an automatic feed boring method for an RV reducer planetary carrier according to an exemplary embodiment; Figure 2 This is a flowchart illustrating a method for determining a cutting state index based on a linkage judgment of spindle vibration data and spindle load power, and adaptively adjusting the feed rate based on the cutting state index, according to an exemplary embodiment. Figure 3 This is a flowchart illustrating a method for obtaining a cutting state index based on a vibration over-limit ratio and a load over-limit ratio, according to an exemplary embodiment. Figure 4This is a flowchart illustrating a method for performing graded feed rate adjustment based on the range of the cutting state index, according to an exemplary embodiment. Figure 5 This is a flowchart illustrating another method for performing graded feed rate adjustment based on the range of the cutting state index, according to an exemplary embodiment. Figure 6 This is a flowchart illustrating a method for obtaining a tool wear state coefficient based on vibration trend offset and load trend offset in each machining operation, and adjusting the U-axis extension of a boring tool based on the tool wear state coefficient, according to an exemplary embodiment. Figure 7 This is a flowchart illustrating a method for obtaining a tool wear trend coefficient according to an exemplary embodiment; Figure 8 This is a flowchart illustrating a method for calculating the total compensation coefficient and determining the actual machining coordinates to perform boring machining, according to an exemplary embodiment. Figure 9 This is a flowchart illustrating a method for performing online inspection after machining to verify the positional accuracy of the hole system and form a data closed loop, according to an exemplary embodiment. Detailed Implementation

[0017] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0018] Figure 1 This is a flowchart illustrating an automatic feed boring method for an RV reducer planetary carrier according to an exemplary embodiment. Figure 1 As shown in the figure, this application provides an automatic feed boring method for an RV reducer planetary carrier, which may include the following steps: In step S10, spindle vibration data and spindle load power during the machining process are acquired.

[0019] In step S20, the cutting state index is determined by linkage judgment based on the spindle vibration data and the spindle load power, and the feed rate is adaptively adjusted based on the cutting state index to control the rate of cutting heat generation.

[0020] In step S30, the tool wear state coefficient is obtained based on the vibration trend offset and load trend offset in each machining operation, and the U-axis extension of the boring tool is adjusted based on the tool wear state coefficient.

[0021] In step S40, the temperature difference between the current machining hole position and the reference hole position is used as input, and the tool wear state coefficient is used as the working condition correction factor to calculate the total compensation coefficient and determine the actual machining coordinates to perform boring.

[0022] In step S50, after machining is completed, online inspection is performed to verify the positional accuracy of the hole system and to form a data closed loop to optimize subsequent machining parameters.

[0023] For example, in a specific machining process, this invention first relies on a comprehensive data acquisition phase. An accelerometer installed at the spindle bearing housing collects the spindle radial vibration signal at a sampling frequency of no less than 1 kHz. After hardware filtering, the effective vibration value is calculated to characterize the dynamic stability of the cutting process. Simultaneously, the q-axis current is read from the vector control loop of the CNC system servo drive, and the real-time spindle load power is calculated, which directly reflects the magnitude of the cutting resistance.

[0024] Infrared temperature measurement points positioned at the workpiece clamping location are responsible for sensing the real-time temperature of the workpiece. In addition, the system can read the currently machining hole number, current feed rate, boring bar U-axis extension, and theoretical coordinates of each hole from the CNC system. Before machining the first hole, the initial workpiece temperature and the average vibration and load under new tool conditions are recorded as a benchmark for all subsequent evaluation and compensation calculations. This data acquisition step is fundamental to the entire adaptive machining method, ensuring that all subsequent control logic is built upon real-time and accurate physical measurements.

[0025] Subsequently, the core adaptive control and compensation stage begins. In this stage, feed rate adjustment linked to vibration and load can be implemented first. By calculating the vibration over-limit ratio and the load over-limit ratio, and substituting them into a comprehensive cutting state index formula, the degree of deterioration of the current cutting condition can be accurately quantified. The core of this formula lies in the fact that when vibration and load deteriorate simultaneously, their product effect rapidly amplifies the index value, accurately reflecting the true cutting state under multi-physics coupling. Based on the range of this index, refined graded adjustments can be performed: from high-efficiency feed to standard feed, then to safe feed, and even forced speed reduction when the load reaches a warning threshold, thereby achieving source control of the cutting heat generation rate.

[0026] Next, the trend assessment of tool wear can be performed using the stable phase data accumulated during each machining operation. By comparing the mean deviation of vibration and load between the current hole position and the new tool state, and using a wear trend coefficient that takes into account both deviation consistency and cumulative machining amount, the trend deterioration of working conditions caused by tool wear can be robustly identified and quantified as a wear state coefficient. Based on this, the U-axis compensation amount can be calculated and the CNC system parameters can be updated.

[0027] Based on this, thermal deformation coordinate compensation can be performed finally. Using the temperature of the first hole as a reference, the temperature difference of the current hole is calculated, and combined with a factor reflecting the positional weight of the machining sequence, a basic thermal expansion compensation coefficient is obtained. Simultaneously, the current tool wear state coefficient is compared with the reference value at the time of the first hole to obtain a relative change factor. This factor effectively acts as a unified proxy parameter for deteriorating working conditions, incorporating information on vibration, load, and wear. Finally, the two are multiplied to obtain the total compensation coefficient, and the theoretical coordinates are reverse-corrected to generate the actual machining coordinates for boring.

[0028] After all holes have been machined, this invention also incorporates a comprehensive post-processing and closed-loop optimization mechanism. Once the workpiece has cooled to the specified temperature, online detection can be automatically initiated to measure the actual position of each hole. If the deviation is within acceptable limits, the temperature rise curve, compensation record, and detection results of this machining process are written into the historical database; if the deviation exceeds the tolerance, the deviation data is analyzed to identify any systematic trends, and the basic compensation benchmark value is automatically adjusted accordingly, enabling the compensation parameters to self-learn and self-correct between batches.

[0029] The data closed-loop design of this embodiment enables the machining parameters to be continuously optimized as external factors such as equipment status and ambient temperature change, thereby ensuring the first-pass yield of the planetary carrier hole system position accuracy in a long-term stable manner and significantly improving machining accuracy and efficiency.

[0030] Figure 2 This is a flowchart illustrating a method for determining a cutting state index based on a linkage judgment of spindle vibration data and spindle load power, and adaptively adjusting the feed rate based on the cutting state index, according to an exemplary embodiment. Figure 2 As shown, the spindle vibration data includes the effective vibration value. The step of determining the cutting state index by linking the spindle vibration data and the spindle load power, and adaptively adjusting the feed rate based on the cutting state index, may include the following steps: In step S201, the warning threshold for vibration dimension and the load safety threshold for load dimension are obtained.

[0031] In step S202, the vibration over-limit ratio is obtained based on the ratio of the effective vibration value to the warning threshold of the vibration dimension.

[0032] In step S203, the overload ratio is obtained based on the ratio of the spindle load power to the load safety threshold.

[0033] In step S204, the cutting state index is obtained based on the vibration over-limit ratio and the load over-limit ratio, and graded feed rate adjustment is performed based on the interval of the cutting state index.

[0034] For example, in the implementation of the present invention, acquiring spindle vibration data and load power data is the first step in starting adaptive control. These data are not used directly, but are processed through a series of steps to form control commands.

[0035] Specifically, the effective vibration value can be extracted from the collected vibration signal, which is a key indicator for measuring the smoothness of the cutting process. Simultaneously, the real-time spindle load power can be obtained from the servo drive's control loop, directly reflecting the magnitude of the cutting resistance. To achieve adaptive adjustment of the feed rate, multiple threshold parameters can be preset internally, including a warning threshold for vibration and a load safety threshold for load. These thresholds serve as baselines for judging whether the current cutting state is normal or trending towards deterioration.

[0036] Optionally, the vibration dimensions may include a stability threshold, a warning threshold, and an impact threshold. These three thresholds are obtained through standard cutting tests on a specific machine tool model. During the test, brand-new, sharp cutting tools are used to continuously cut the same batch of planetary carrier blanks at the maximum allowance specified in the process, medium speed, and feed rate. The effective values ​​of spindle vibration throughout the entire process are collected. Statistical analysis was conducted based on this dataset: the root mean square value of the vibration signal was taken as the "stability threshold," representing the expected fluctuation level of normal cutting; the upper limit covering 95% of the data points was taken as the "warning threshold," exceeding which indicates a significant deviation of vibration from normal; and the vibration peak value under extreme conditions such as intentionally introduced hard points or chip entanglement in the experiment was taken as the "impact threshold." These thresholds were fixed in tabular form in the process documents according to different planetary carrier materials and tool combinations.

[0037] The above standard cutting test program can be run during the trial cutting of new products or the first piece processing after equipment overhaul. The control system will automatically collect and calculate the above statistical values, which will be written into the parameter table after confirmation by process personnel.

[0038] The load dimension can include a safe load threshold and a warning load threshold, both of which are directly derived from the machine tool spindle motor's technical specifications and the equipment manufacturer's recommendations. The "safe load threshold" is typically set at 60% of the spindle motor's rated power. This value represents the boundary where the motor's temperature rise and torque output are within a safe and efficient range during long-term continuous operation. The "warning load threshold" is typically set at 80% of the spindle motor's rated power. This represents the maximum allowable short-term continuous load without triggering an overload alarm, and this setting method conforms to general CNC machine tool electrical design specifications.

[0039] The parameters can be preset by the equipment manufacturer in the CNC system parameters, or fine-tuned by the service engineer during equipment installation and commissioning based on the on-site power grid and cooling conditions. Modification permissions are usually not granted to end users.

[0040] Based on the above data and thresholds, the linkage judgment can begin. First, by calculating the ratio of the effective vibration value to the vibration warning threshold, a vibration exceedance ratio can be obtained. This ratio quantifies the degree of deviation of the current vibration level from the safety benchmark. Similarly, by calculating the ratio of the real-time spindle load power to the load safety threshold, a load exceedance ratio can be obtained, which measures whether the current cutting resistance is within the safe range. These two exceedance ratios are the core elements for constructing the cutting state index.

[0041] For example, vibration exceedance ratio It can be obtained from the following formula: Formula 1 in, This is the effective value of vibration. This is the warning threshold, and this value is not zero.

[0042] Overload ratio It can be obtained from the following formula: Formula 2 in, Main spindle load power, This is the load safety threshold, and this value is not zero.

[0043] Then, these two over-limit ratios can be substituted into a preset function. The characteristic of this function is that when either vibration or load exceeds the limit, the exponent will increase accordingly; and when both exceed the limit at the same time, since the numerator is the product of the two and the denominator is the sum of the two, the exponent will increase more rapidly, thus accurately reflecting the severity of the overall deterioration of the cutting condition. This calculated cutting condition exponent becomes the direct basis for implementing feed rate adjustment.

[0044] Based on the magnitude of the cutting condition index, a tiered adjustment strategy can be implemented. This strategy divides the index value into several intervals, each corresponding to a different feed rate level. When the index value is very low, indicating a very stable cutting condition, a higher "high-efficiency feed rate" can be selected to improve machining efficiency. When the index value rises to a certain intermediate range, indicating a slight abnormality in cutting, the feed rate can be proactively reduced to a "standard feed rate" to slow down the rate of cutting heat generation and prevent further deterioration of the working condition. When the index value exceeds a higher threshold, indicating a severely deteriorated cutting condition, the lowest "safe feed rate" can be enforced to minimize the rate of cutting heat generation, prioritizing machining safety and workpiece quality.

[0045] The graded adjustment in this embodiment is not a simple on / off control, but a refined proactive management based on real-time operating condition scoring, which can ensure efficiency under normal conditions and effectively curb the risk of thermal deformation under abnormal conditions.

[0046] Figure 3 This is a flowchart illustrating a method for obtaining a cutting state index based on vibration over-limit ratio and load over-limit ratio, according to an exemplary embodiment. Figure 3 As shown, obtaining the cutting state index based on the vibration over-limit ratio and the load over-limit ratio may include the following steps: In step S2041, the number of sampling periods of the current state and the preset sampling count threshold are obtained.

[0047] In step S2042, the cutting state index is obtained based on the number of sampling cycles, the sampling count threshold, the vibration over-limit ratio, and the load over-limit ratio.

[0048] For example, to more accurately reflect the evolution trend of the cutting state and avoid misadjustments caused by instantaneous disturbances, this invention introduces a stability correction factor that reflects the duration of the state when calculating the cutting state index. The design idea is that a single or short-term vibration or load fluctuation may be caused by random factors such as localized hard spots in the workpiece or chip entanglement, and does not represent an inherent deterioration of the cutting condition. However, if the abnormal state persists, it indicates that a systematic instability has indeed occurred in the cutting process, requiring intervention.

[0049] Based on this, when calculating the comprehensive cutting condition index, in addition to relying on the current vibration over-limit ratio and load over-limit ratio, the number of sampling cycles during which the current abnormal state lasts can also be obtained and compared with a preset sampling count threshold. This threshold depends on the sampling frequency of the vibration signal and the response cycle of the control system. Its setting is to balance "rapid response to abnormal working conditions" and "avoiding erroneous adjustments caused by transient interference." Its value is determined through testing: a transient vibration disturbance (such as short-term chip impact) is artificially introduced, and the system is observed to determine the sampling cycle within which the disturbance can be effectively filtered out. Simultaneously, the shortest number of cycles required from the onset of actual working condition deterioration to the vibration signal stabilizing and exceeding the threshold is recorded. The number of cycles that can filter out more than 90% of transient interference and has a response delay of no more than 0.5 seconds is taken as the set value. During the equipment commissioning phase, by executing a test cycle containing artificial interference, the control system can automatically analyze and recommend an optimal sampling count threshold, which is then set after confirmation by engineers.

[0050] This preset counting threshold can be understood as the system's "tolerance" or observation window for abnormal states. The ratio of the number of sampling periods to the sampling counting threshold can be used as a denominator in the calculation formula of the cutting state index. The ingenuity of this design lies in the fact that when an abnormal state has just occurred and the number of periods is small, the value of this denominator is large, thus lowering the overall cutting state index and preventing the system from immediately triggering a speed reduction action, avoiding unnecessary loss of production efficiency due to occasional events. Conversely, if the abnormal state persists, causing the number of sampling periods to approach or exceed the preset sampling counting threshold, the value of this denominator will gradually decrease to close to 1. At this point, the cutting state index truly reflects the combined deterioration of vibration and overload ratio, and the corresponding feed rate reduction operation can be performed accordingly.

[0051] For example, the cutting condition index It can be obtained from the following formula: Formula 3 in, This is the number of sampling periods, which is not zero in this scenario. This is the sampling count threshold, and this value is not zero. To adjust the constants, all values ​​are set to 1 to prevent the denominator from being zero.

[0052] This mechanism in the embodiments of this application makes the feed rate adjustment decision more robust and reasonable, effectively balancing the conflict between processing safety and processing efficiency.

[0053] Figure 4 This is a flowchart illustrating a method for adjusting the graded feed rate based on the range of the cutting state index, according to an exemplary embodiment. Figure 4 As shown, the step of performing graded feed rate adjustment based on the range of the cutting state index may include the following steps: In step S2043, when the cutting state index is less than or equal to the first preset threshold and the load over-limit ratio is less than or equal to 1, the feed rate is set to a high-efficiency feed rate.

[0054] In step S2044, when the cutting state index is greater than the first preset threshold and less than or equal to the second preset threshold, the feed rate is reduced to the standard feed rate.

[0055] In step S2045, when the cutting state index is greater than the second preset threshold, the feed rate is forcibly reduced to the safe feed rate, the high-efficiency feed rate is greater than the standard feed rate, and the standard feed rate is greater than the safe feed rate.

[0056] For example, after establishing the calculation method of the cutting state index, this invention further refines the specific logic for performing graded feed rate adjustment based on the index, so as to achieve fine control of the cutting heat generation rate. This adjustment logic sets clear boundary thresholds and corresponding feed rate levels, forming a clear control strategy that is easy to implement in a CNC system.

[0057] Specifically, a lower first preset threshold can be set first. and a higher second preset threshold These two thresholds divide the cutting condition index into three main ranges. Simultaneously, three feed rate levels are preset internally, namely, high-efficiency feed rates. Standard feed rate and safe feed rate The value decreases progressively. In each sampling or control cycle, the current cutting state index can be calculated in real time, and its range can be determined. When the cutting state index is less than or equal to the first preset threshold, and the load overload ratio is less than or equal to 1, this indicates that the current cutting process is very smooth, the cutting resistance is within a safe range, and it is an ideal machining state. To maximize production efficiency, the feed rate can be set to a high-efficiency feed rate.

[0058] When the cutting condition index is greater than the first preset threshold but less than or equal to the second preset threshold, it indicates that a certain degree of abnormality has occurred during the cutting process, but it has not yet reached a point of serious deterioration. At this point, instead of immediately taking the most severe measures, a preventative strategy can be adopted: uniformly reducing the feed rate to the standard feed rate. The purpose of this adjustment is to proactively reduce the cutting intensity, slow down the rate of cutting heat generation, and prevent more severe tool wear and thermal deformation caused by excessive heat accumulation. When the cutting condition index is greater than the second preset threshold, it indicates that the cutting condition has seriously deteriorated, and the combined effects of vibration and load have exceeded the safety boundary. At this point, decisive intervention is necessary, forcibly reducing the feed rate to the minimum safe feed rate, sacrificing some machining efficiency to fully ensure the stability of the machining process and the quality of the workpiece, and controlling the cutting heat input to the lowest level to avoid workpiece scrap due to thermal runaway.

[0059] For example, it can be based on The interval and , The specific combination will be subject to tiered adjustment: 1. The index is in a slightly abnormal range, but the vibration and load are not exceeded. when < ≤ ,but ≤1 and A value ≤1 indicates that although the individual indicators of vibration and load are within safe ranges, the combined effect of the two has caused the overall cutting condition index to enter a slightly abnormal range. This situation is common in a "sub-healthy" state where both vibration and load are close to but have not yet exceeded their respective thresholds. At this point, the vibration condition indicator... Set to 0, load status flag Set to 0, but uniformly reduce the feed rate to the standard feed rate. This is a preventative speed reduction measure to prevent the operating conditions from deteriorating further.

[0060] 2. The index is within the good range, but either vibration or load has exceeded the limit. when ≤ ,but > 1 or A value >1 indicates that although the overall index is rated as excellent, a single indicator has exceeded its limit. This situation usually occurs because the excellent performance of another indicator is suppressing the rise of the overall index. In this case, the system cannot ignore the warning signal of a single indicator exceeding its limit. >1 and ≤1, will Set to 1, Set to 0 to maintain efficient feed rate. The status remains unchanged, but the system internally marks this state as "requiring attention" and shortens the sampling period for subsequent monitoring to enable a rapid response if the vibration worsens. If >1 and ≤1, similarly Set to 1, Set to 0, feed rate maintained However, it has also entered a "needs attention" status.

[0061] 3. The index is in a severely deteriorated range, but the vibration and load are not exceeding the limits. when > ,but ≤1 and When the value is ≤1, this situation is relatively rare and is usually caused by a small sampling count Ncount. The cutting condition index is abnormally amplified, or this is due to the cumulative effect of historical data in the index calculation. In this case, since the actual measured values ​​of vibration and load are within safe limits, the system does not determine it as a true deterioration but instead lowers the feed rate to the standard feed rate. Instead of forcibly reducing to a safe feed rate Meanwhile, the system marks this state as "to be observed," and will decide whether to further reduce the speed after reassessment in the next sampling cycle.

[0062] 4. Vibration status marking Applicable scenarios for 2 = 2 Only when the cutting condition is judged as "severely deteriorated" and It can only be set when the value is greater than 1. In any other state, even if... >1, The maximum value is only 1. =2 indicates that the vibration has exceeded the warning threshold and reached the impact threshold level. This mark will trigger additional correction and amplification in the subsequent tool wear assessment and thermal deformation compensation process, so its setting conditions are strictly limited.

[0063] Among them, the preset cutting state index threshold and This is derived from a comparative analysis of qualified and abnormal workpieces in a historical machining database. A large amount of sensor data was collected during normal machining and during abnormal machining processes such as vibration marks and dimensional deviations, and the corresponding cutting state indices were calculated for each. By using receiver operating characteristic (ROC) curves or cluster analysis, the critical values ​​that best distinguish between "excellent / stable" and "slightly abnormal" operating conditions, as well as "slightly abnormal" and "severely deteriorated" operating conditions, are determined, thereby defining... and .

[0064] After the production line has been running stably for a period of time, process engineers can retrieve data from the historical database, run background analysis scripts, and the system will recommend new thresholds. After review by process engineers, the new thresholds can be updated into the system, achieving adaptive optimization of thresholds based on equipment status.

[0065] Preset feed rates of high efficiency, standard, and safety. , , It is a formal process specification directly derived from the boring process of the planetary carrier. This refers to the standard cutting parameters specified on the process card. It is determined based on standard parameters, combined with high-performance cutting parameters recommended by the tool supplier, and verified through process tests to ensure that it has no impact on quality (surface roughness, dimensional accuracy) under stable working conditions. It is determined based on the machine tool's minimum stable feed rate or the minimum cutting thickness to ensure chip breaking, and is the minimum guaranteed speed to maintain the continuous cutting process.

[0066] It can be determined by process engineers during the new product introduction phase through cutting tests, and written into the macro variables of the CNC machining program or the process database in the form of parameters.

[0067] Figure 5This is a flowchart illustrating another method for performing graded feed rate adjustment based on the range of the cutting state index, according to an exemplary embodiment. Figure 5 As shown, the step of performing graded feed rate adjustment based on the range of the cutting state index may further include the following steps: In step S2046, when the spindle load power reaches the load warning threshold of the load dimension, regardless of the value of the cutting state index, the feed rate is forcibly reduced to the safe feed rate, and the load warning threshold is greater than the load safety threshold.

[0068] In step S2047, when the cutting state index falls below the first preset threshold and the load over-limit ratio is less than or equal to 1 and is maintained for a sampling count threshold number of sampling cycles, the feed rate is restored to the high-efficiency feed rate in a stepwise manner.

[0069] For example, based on the graded feed rate adjustment strategy, this application also includes several special condition logics and recovery logics to cope with extreme working conditions and ensure the stability of system operation. These supplementary rules make the entire control strategy more rigorous and complete, and adapt to various complex situations that may occur in actual processing.

[0070] First, for the most hazardous condition of overload, a separate, highest-priority judgment rule can be established. Specifically, when the spindle load power is detected to reach or exceed a preset load warning threshold, regardless of the result calculated by the comprehensive cutting condition index, the system will immediately and forcibly reduce the feed rate to the safe feed rate. This design is based on a profound understanding of machining safety: continuous high load means extremely high cutting resistance, which not only generates a sharp increase in cutting heat but may also lead to serious accidents such as tool breakage and spindle overload. Therefore, overload is considered a dangerous condition that must be dealt with unconditionally, and its handling authority surpasses that of conventional comprehensive condition assessment.

[0071] Secondly, a smooth recovery logic can be designed to avoid frequent switching of the feed rate between high and low levels, which could affect the quality of the machined surface and the lifespan of the machine tool. When the cutting condition index, after experiencing an abnormal period, falls back below the first preset threshold, and the overload ratio also recovers to a safe range (less than or equal to 1), the system will not immediately jump the feed rate from the safe or standard level back to the high-efficiency level. Instead, this favorable state can be required to be maintained continuously and stably for a preset sampling count threshold number of cycles. Only when this stability condition is met can a step-wise recovery process be executed to gradually increase the feed rate back to the high-efficiency level.

[0072] For example, when (i.e., when the load reaches the warning threshold), regardless of Regardless of the value, the feed rate is forced to decrease. Because the harm of sustained overload takes precedence over any other factor, The load warning threshold is typically set at 80% of the rated power. The load safety threshold is typically 60% of the rated power.

[0073] when Falling back to The following and and maintain continuously After one cycle, the system will gradually restore the feed rate to [normal value]. All status flags are restored to 0.

[0074] Optionally, feed rate step recovery may include the following steps: 1. Determining the trigger condition for recovery When the cutting state index Falling back to the first preset threshold Below, and the load over-limit ratio Furthermore, this favorable state is maintained continuously and stably at the preset sampling count threshold. After one sampling period, the system determines that the operating condition has stabilized and recovered from the abnormal state, and starts the step-by-step recovery procedure.

[0075] 2. Preset Stepped Recovery Sequence The system internally pre-sets a stepped sequence for restoring from a safe or standard feed rate to an efficient feed rate. This sequence includes... A recovery step ( Typically, 2 to 3 are used, with each step corresponding to an intermediate feed rate value, arranged in ascending order. For example, if the current feed rate is the standard feed rate... The goal is to achieve a high feed rate. Then set an intermediate step. If the current feed rate is the safe feed rate. Then, two intermediate steps are set, in order as follows: and .

[0076] 3. Maintaining stability and confirming status between steps Starting from the current feed rate, after each adjustment to the next feed rate step, the system must continuously run for a preset step stabilization period on that step. Each sampling period ( Usually taken (50% to 100%). During the stabilization period of each step, the system continuously monitors... and If during this period, Breakthrough again or If the condition is not met, the recovery procedure is immediately stopped, the feed rate is adjusted back to the value of the previous step or directly back to the original position before the recovery was triggered, and the grade adjustment is re-executed according to the new cutting condition index. If the condition remains good throughout the entire step stabilization cycle, the next step is initiated.

[0077] 4. Complete recovery and clear status flags. When the feed rate passes through all intermediate steps and finally reaches the high-efficiency feed rate And it runs stably in that gear. After one sampling period, the system confirms that the recovery is complete and marks the vibration state. and load status flags All data has been reset to zero, restoring normal monitoring status.

[0078] This graded adjustment mechanism keeps the cutting heat within a controllable range, suppressing the tendency of thermal deformation to intensify from the source.

[0079] The recovery mechanism with hysteresis and filtering characteristics in this embodiment effectively prevents repeated oscillations in the feed rate caused by minor fluctuations in the cutting state, thus ensuring the smoothness of the cutting process and the tool life.

[0080] Figure 6 This is a flowchart illustrating a method for obtaining a tool wear state coefficient based on vibration trend offset and load trend offset during each machining operation, and adjusting the U-axis extension of a boring bar based on the tool wear state coefficient, according to an exemplary embodiment. Figure 6 As shown, the step of obtaining the tool wear state coefficient based on the vibration trend offset and load trend offset in each machining operation, and adjusting the U-axis extension of the boring tool based on the tool wear state coefficient, may include the following steps: In step S301, when machining the first hole in the new tool state, the first average vibration value and the first average load value of the smooth cutting stage are obtained.

[0081] In step S302, after machining the target hole, the second average vibration value and the second average load value during the smooth cutting phase of the target hole machining process are obtained, and the target hole is any machined hole after the first hole.

[0082] In step S303, the vibration trend offset ratio is determined based on the ratio of the second vibration average to the first vibration average, and the load trend offset ratio is determined based on the ratio of the second load average to the first load average.

[0083] In step S304, the tool wear trend coefficient is obtained based on the vibration trend offset ratio and the load trend offset ratio, and the tool wear trend coefficient is directly mapped to the tool wear state coefficient.

[0084] In step S305, the tool wear compensation amount is obtained according to the tool wear state coefficient, and the U-axis extension amount of the boring tool is adjusted according to the tool wear compensation amount.

[0085] For example, this invention designs an indirect evaluation and compensation method based on the trend of machining parameters, targeting tool wear, a key factor affecting machining accuracy. This method does not rely on additional hardware sensors, but rather senses the evolution of tool condition by analyzing existing vibration and load data. It has the advantages of low cost, sensitive response, and direct correlation with the cutting process.

[0086] When a new cutting tool is used for the first time, an initial state baseline can be established. This baseline is obtained during the smooth cutting phase of machining the first hole, including the average vibration and load values ​​during this phase. These two averages represent the cutting characteristics of the tool under optimal conditions. The control system will traverse each subsequent hole as a target hole according to a predetermined machining sequence. After machining a subsequent target hole, the average vibration and load values ​​during the smooth cutting phase of that hole machining can be extracted again. By dividing the current target hole's average vibration value by the initial average vibration value, a vibration trend offset ratio can be obtained. A ratio greater than 1 reflects a relative increase in vibration level. Similarly, by dividing the current target hole's average load value by the initial average load value, a load trend offset ratio can be obtained. The magnitude of this ratio reflects the relative increase in cutting resistance. These two offset ratios are the basic data for assessing tool wear.

[0087] To transform these raw offset ratios into a reliable, quantifiable indicator of wear status, a tool wear trend coefficient can be further constructed. The core of this coefficient's construction lies in examining the consistency between vibration offset and load offset. When tool wear is the primary cause of deteriorating working conditions, it typically leads to increased cutting resistance (increased load) and instability in the cutting process (intensified vibration). Therefore, the offset ratios of these two factors will show a synchronous upward trend with similar values. In this case, a higher wear coefficient value can be assigned. Conversely, if there is only vibration offset while the load is normal, or vice versa, it indicates that the current anomaly is more likely caused by sudden changes in the blank allowance or other instantaneous disturbances, rather than true tool wear. In this case, the wear coefficient value can be effectively suppressed by taking a smaller value, dividing it by a larger value, and adding a constant, thus avoiding misjudgment. This coefficient is also multiplied by a confidence factor based on the number of machined holes, making the evaluation results more conservative in the early stages of tool life. The weight gradually increases as machining data accumulates. The final output tool wear status coefficient is used to calculate the U-axis compensation amount, achieving proactive compensation for the impact of tool wear.

[0088] Then, the tool wear trend coefficient is directly used as the tool wear state coefficient.

[0089] For example, the vibration trend offset ratio It can be obtained from the following formula: Formula 4 in, The second vibration mean, The mean value of the first vibration. To adjust the constant, a value of 0.01 is used to prevent the denominator from being zero, and to ensure the dimensions are consistent with... Same, for .

[0090] Load trend offset ratio It can be obtained from the following formula: Formula 5 in, The second average load, The first load average, To adjust the constant, a value of 0.01 is used to prevent the denominator from being zero, and to ensure the dimensions are consistent with... Same, for .

[0091] Tool wear compensation It can be obtained from the following formula: Formula 6 in, This is the maximum allowable wear compensation for the tool (determined by the tool manufacturer's recommendation or process testing). This is the tool wear condition coefficient.

[0092] The larger, The closer to the maximum allowable value, the more the U-axis extends to compensate for wear. The updated U-axis extension amount will be adjusted accordingly. ( The reference U-axis extension amount (when the new tool is used) is written into the CNC system and takes effect in the machining of the next hole.

[0093] when Exceeding the preset tool change warning threshold When the value is typically 0.8, the system issues a tool change prompt.

[0094] Preset maximum tool wear compensation Tool change warning threshold ,in, This information primarily comes from the tool manufacturer's technical manual, which specifies the maximum permissible wear (such as the width of the flank wear band) for that model of boring bar insert when machining specific materials. Then, the maximum radial compensation is calculated based on the principal cutting edge angle of the boring tool. It is typically set to 0.8, which is a common equipment management metric that indicates an alert is issued when 80% of the tool's lifespan is reached, allowing sufficient time to prepare the tool.

[0095] You can directly enter the model and grade of the purchased cutting tools in the system's tool management interface. It can be set uniformly in the equipment management system, or it can be fine-tuned according to the workshop's tool preparation strategy.

[0096] Figure 7 This is a flowchart illustrating a method for obtaining a tool wear trend coefficient according to an exemplary embodiment. Figure 7 As shown, obtaining the tool wear trend coefficient may include the following steps: In step S3041, the cumulative value of the number of processed holes and the preset reference number of holes are obtained.

[0097] In step S3042, the tool wear trend coefficient is obtained based on the cumulative value, the number of reference holes, the vibration trend offset ratio, and the load trend offset ratio.

[0098] For example, in order to improve the accuracy and robustness of tool wear assessment, this invention introduces a confidence weighting mechanism based on the cumulative value of the number of machined holes when calculating the tool wear trend coefficient. The core concept of this design is that tool wear is a gradual process, and the reliability of its trend assessment should increase as the amount of accumulated machining data increases.

[0099] Specifically, in calculating this coefficient, in addition to using the vibration trend offset ratio and load trend offset ratio, two key parameters can be obtained: first, the cumulative number of holes currently machined by the tool, which directly reflects the tool's lifespan consumption; and second, a preset reference number of holes, which can be set based on the total number of holes on the planetary carrier, typically twice the total number of holes, as a benchmark for measuring the reliability of the assessment. These two parameters can be combined into a weighting factor, mathematically expressed as the cumulative value divided by the sum of the cumulative value and the reference number of holes.

[0100] The characteristic of this weighting factor is that when the cumulative value is small, the factor is also small. This means that in the early stages of a new tool's break-in, even if vibration and load data show some deviation, the system assigns a low weight to them and will not immediately judge them as severe wear. This provides a buffer for the tool's initial break-in and adaptation. As the number of machined holes increases, the cumulative value becomes larger and larger, and the weighting factor gradually approaches 1. This means that the system becomes more confident in the wear trend indicated by the vibration and load deviation ratio, and the evaluation results become more certain and sensitive.

[0101] For example, tool wear trend coefficient It can be obtained from the following formula: Formula 7 in, This is the cumulative value of the number of holes processed. The preset reference number of holes, To adjust the constant, a value of 1 is set to prevent the denominator from being zero. To obtain the minimum value, To obtain the maximum value.

[0102] It should be noted that, The parameter is used for confidence weighting in tool wear assessment. It is set to twice the total number of holes on the planetary carrier, based on the statistical principle of sample size: the sample mean is only sufficiently robust to the true trend when the data size is more than twice the total number of holes. For standard planetary carriers (e.g., total number of holes...), Multiplying this by 2 means that the confidence level of the wear assessment will only approach 1 after at least two complete sets of workpieces have been machined. This can be automatically calculated in the machining program based on the planetary carrier model currently being machined. .

[0103] This expression consists of the product of two fractional factors. The first factor... Reflects the degree of consistency between vibration offset and load offset: when and When both indicators rise synchronously and their values ​​are close, it indicates that the trends in the two dimensions are consistent, and the wear assessment is reliable. When only a single indicator deviates, if the numerator is taken as the smaller value of 1.0 and the denominator is taken as the larger value of 1.8 plus 1, the factor is suppressed. This effectively avoids misjudging wear due to occasional fluctuations in operating conditions causing a single indicator to become abnormal; when neither of these two indicators deviates significantly (both are close to 1), the factor is approximately This indicates that the cutting tool is still in normal condition.

[0104] Second Factor A confidence-weighted average of cumulative processing volume in wear assessment. The larger the value, the closer the factor is to 1, and the higher the confidence level of the trend assessment; in the new knife stage ( (If the factor is smaller, the weight of trend judgment will be reduced accordingly.)

[0105] The embodiments of this application effectively adjust the sensitivity of the wear trend coefficient to the original data through the weighting factor, avoiding false alarms caused by small sample data fluctuations in the early stage of tool life, and reflecting the wear status in a timely and accurate manner in the middle and late stages of tool life, providing a reliable basis for subsequent compensation and tool replacement decisions.

[0106] Figure 8 This is a flowchart illustrating a method for calculating the total compensation coefficient and determining the actual machining coordinates to perform boring machining, according to an exemplary embodiment. Figure 8 As shown, calculating the total compensation coefficient and determining the actual machining coordinates to perform boring may include the following steps: In step S401, the workpiece temperature at the moment the first hole is completed is used as the temperature reference, and the tool wear state coefficient at the moment the first hole is completed is used as the tool working condition reference.

[0107] In step S402, the difference between the workpiece temperature and the temperature reference for machining the current hole position is obtained, as well as the tool wear state coefficient when machining the current hole position.

[0108] In step S403, the thermal expansion basic compensation coefficient is calculated based on the difference between the workpiece temperature at the current hole position and the temperature reference.

[0109] In step S404, a relative change factor is calculated based on the ratio of the tool wear state coefficient when machining the current hole position to the tool working condition reference, and the product of the thermal expansion basic compensation coefficient and the relative change factor is used as the total compensation coefficient.

[0110] In step S405, the actual machining coordinates of each hole are calculated based on the total compensation coefficient and the preset basic compensation reference value, and the actual machining coordinates are written into the interpolation command of the CNC system to perform boring.

[0111] For example, after completing the adaptive feed rate control and tool wear assessment, the ultimate and most important goal of this invention is to achieve thermal deformation coordinate compensation based on temperature differences and wear conditions. This step directly affects the machining positioning process and is the core means to ensure the position accuracy of the hole system.

[0112] First, the workpiece temperature at the moment the first hole is completed can be set as the temperature benchmark for the entire compensation calculation. Simultaneously, the tool wear state coefficient obtained from the wear assessment stage at the moment the first hole is completed can be used as the tool condition benchmark. These two benchmark values ​​define the workpiece thermal field and tool conditions in the initial state.

[0113] When machining subsequent holes, the workpiece temperature at the current hole location can be obtained, and the difference between it and the temperature reference can be calculated. This temperature difference directly drives the calculation of the thermal expansion compensation coefficient. This coefficient is designed considering two factors: first, the absolute magnitude of the temperature rise—the higher the temperature rise, the more significant the thermal expansion; and second, the positional weight of the machining sequence—the later the hole, the longer the time interval between it and the first hole, resulting in a more sufficient heat accumulation effect. Therefore, this coefficient accurately reflects the amount of thermal drift at the current hole location due to the overall temperature rise of the workpiece.

[0114] More importantly, when calculating the final total compensation coefficient, the system does not rely solely on temperature data. Instead, it introduces the tool wear state coefficient as a key condition correction factor. By calculating the ratio of the current tool wear state coefficient to the first hole reference coefficient, a relative change factor can be obtained. This factor acts as a "condition deterioration amplifier." When tool wear intensifies, it increases cutting resistance and generates more frictional heat. Simultaneously, the increase in the wear state coefficient indirectly reflects the increased vibration and load monitored in previous stages, all of which contribute additionally to thermal deformation. Therefore, when this relative change factor is greater than 1, it means that the degree of thermal deformation under the current conditions will be more severe than predicted solely by temperature differences. This factor can be multiplied by the thermal expansion basic compensation coefficient to obtain the total compensation coefficient.

[0115] Finally, based on this total compensation coefficient and the preset basic compensation benchmark value, the theoretical X and Y coordinates of each hole position can be reversed to generate the actual machining coordinates. These actual coordinates take into account the offset caused by thermal expansion and deterioration of working conditions, ensuring that the hole position can return to the theoretical design position after cooling, thereby greatly improving the positional accuracy.

[0116] For example, the workpiece temperature at the current hole position i. With temperature reference The difference It can be obtained from the following formula: Formula 8 The larger the value, the higher the overall temperature of the workpiece during hole machining, the more severe the thermal expansion, and the greater the amount of hole shrinkage after cooling.

[0117] Thermal expansion basic compensation coefficient It can be obtained from the following formula: Formula 9 in, This is a temperature reference value (taken as 5℃), used to scale the effect of temperature rise. Let i be the total number of holes and i be the current hole sequence. To adjust the constant, a value of 0.01 is set to prevent the denominator from being zero.

[0118] It should be noted that, (5℃) is a scaling constant used to dimensionlessly represent the temperature rise effect. It is selected based on the typical temperature fluctuation range of a workshop environment. In a constant-temperature workshop, this value can be smaller (e.g., 2℃); in a general workshop, it can be 5-10℃. It can be set by the equipment installation engineer according to the workshop temperature control conditions.

[0119] This expression consists of the product of two fractional factors: the first factor This reflects the temperature rise of the current hole relative to the first hole; the greater the temperature rise, the more significant the thermal expansion, and the stronger the compensation requirement; the second factor. The positional weight reflects the processing sequence; the later a hole is processed, the longer the processing time between it and the first hole, resulting in more sufficient heat accumulation and a greater need for compensation. When the factor is zero, This is consistent with the design where the first hole does not perform compensation.

[0120] relative change factor It can be obtained from the following formula: Formula 10 in, This is the tool wear coefficient when machining the current hole position i. As a reference for tool operating conditions, To adjust the constant, a value of 1 is set to prevent the denominator from being zero.

[0121] when hour, This indicates that the tool wear condition is consistent with the reference and no additional correction is required; when hour, This indicates that tool wear is more severe than with the reference hole, cutting conditions deteriorate, frictional heat increases, and amplification compensation is required. Because... It already integrates information on the trend and offset of vibration and load. The increase in temperature not only reflects tool wear, but also indirectly reflects the additional contribution of increased cutting vibration and load to thermal deformation.

[0122] Total compensation coefficient It can be obtained from the following formula: Formula 11 Actual positioning coordinates during processing ( )for: / 1000 Formula 12 / 1000 Formula 13 in, For Kong Xu Theoretical coordinates and The basic compensation reference value (positive value) is the unit compensation amount (in μm / mm) for the X-axis and Y-axis, respectively, which is preset by the machine tool manufacturer according to the typical thermal deformation law of this model of planetary carrier.

[0123] Preset basic compensation benchmark value and This comes from the "thermal deformation test" conducted by machine tool manufacturers before the equipment leaves the factory. During the test, the actual machining conditions (speed, feed, cooling) are simulated and the machine runs continuously for several hours. Precision equipment such as a laser interferometer is used to measure the spatial displacement of the spindle and workpiece table under different temperature rises, and a mapping relationship between temperature rise and displacement is established. and This refers to the basic compensation coefficient of the mapping relationship under standard temperature rise conditions. It can be used as an inherent parameter of the machine tool and written into the compensation parameter table of the CNC system by the manufacturer. After equipment overhaul or precision adjustment, it can be recalibrated and updated by professional service personnel.

[0124] The compensation principle is: thermal expansion causes each hole to shift radially outward, located in the positive direction of the origin ( The hole is offset in the positive direction, located in the negative direction of the origin ( The holes in the positive direction will shift to a more negative direction. After cooling, the actual position of the hole in the positive direction will be greater than the theoretical coordinate, and the actual position of the hole in the negative direction will be less than the theoretical coordinate (i.e., the absolute value will be larger).

[0125] The CNC system will correct the coordinates , Write the interpolation command to execute the boring process on the hole. After machining, record the actual compensation amount, temperature difference value, and tool wear state coefficient of the hole for subsequent data traceability and trend analysis.

[0126] Figure 9 This is a flowchart illustrating a method for performing online inspection after machining to verify the positional accuracy of the hole system and form a data closed loop, according to an exemplary embodiment. Figure 9 As shown, the online inspection performed after processing to verify the positional accuracy of the hole system and form a data closed loop may include the following steps: In step S501, after all holes have been machined, when the workpiece temperature drops back to within the sum of the initial temperature and the cooling completion threshold, the actual coordinate position of each hole is measured and the positional deviation is calculated.

[0127] In step S502, if the positional deviation is within the preset tolerance range, the temperature rise curve, compensation record and test results of this processing are written into the historical database.

[0128] In step S503, if the positional deviation exceeds the preset tolerance range, the deviation data is compared and analyzed with historical data. If the deviation shows a systematic trend, the basic compensation benchmark value is adjusted to form a closed-loop optimization of processing-compensation-detection-update.

[0129] For example, after completing the boring of all holes, the present invention may also include an online detection and data closed-loop step. This step connects the machining process with subsequent optimization, making the method an intelligent system with self-learning and self-adaptive capabilities, rather than just a set of fixed control commands.

[0130] After all holes are machined, the workpiece needs to undergo a cooling phase. The cooling process continues until the workpiece temperature has returned to its initial temperature plus a small cooling completion threshold. Within the time limit, ( Typically, a temperature of 2°C is used, which indicates that the workpiece has returned to room temperature. Only at this point do the measured hole dimensions and positional accuracy have final evaluative significance. Subsequently, an online detection program can be started, using the machine tool's built-in probe or other online measuring equipment to measure the actual coordinate positions of each hole and calculate their positional accuracy deviations relative to the theoretical positions. This step is the final criterion for verifying the effectiveness of all previous adaptive control and compensation measures.

[0131] It should be noted that, It can be set according to precision measurement specifications, typically requiring the temperature difference between the workpiece and the ambient temperature to not exceed 2℃ to ensure measurement accuracy and avoid the influence of thermal expansion and contraction on the measurement results. It can be set according to the company's internal testing standards or with reference to national standards (such as GB / T 17421).

[0132] Based on the test results, different data flows and processing logics can be executed. If the calculated positional deviation is within the preset tolerance range, it indicates that the processing is successful. All key data recorded during the processing, including the entire temperature rise curve, coordinate compensation records for each step, and the final test results, can then be written into the historical database. This data provides valuable offline analysis information for process engineers and supports subsequent process optimization.

[0133] If the positional deviation exceeds the tolerance range, the system does not simply discard the data but initiates a deep analysis process. It compares the current deviation data with historical batch data stored in the database. If a systematic trend is found—for example, three consecutive batches showing the same tendency of deviation in the same direction at the same hole position—it can be inferred that the current preset basic compensation benchmark value may have a systematic deviation and needs correction. Based on this judgment, the basic compensation benchmark value can be automatically and gradually adjusted to more closely approximate the actual physical compensation amount.

[0134] Optionally, the correction process can be as follows: 1. Identification and Judgment of Systematic Biases When the positional deviation exceeds the tolerance range, the system marks the workpiece's deviation data (including the deviation hole position, deviation direction, deviation value, temperature rise curve during machining, tool wear condition, etc.) as "out of tolerance" and stores it. Subsequently, the system retrieves out-of-tolerance records for the same model planetary carrier, the same hole position, and the same deviation direction from the historical database.

[0135] If continuous batches ( Typically, if the test data in step 3) simultaneously meet the following three conditions, a systematic bias is considered to exist: Directional consistency: The deviation direction is the same, that is, it is the same direction among the positive X-axis direction, negative X-axis direction, positive Y-axis direction, or negative Y-axis direction.

[0136] Numerical persistence: The absolute value of the deviation for each batch exceeds the preset deviation alarm threshold. (This threshold is typically set to 50% to 80% of the tolerance, which is less than the formal out-of-tolerance threshold, and is used to capture early trends.)

[0137] Trend monotonicity: The absolute value of the deviation shows a monotonically decreasing trend, that is, the absolute value of the deviation of subsequent batches is not less than that of the previous batch.

[0138] 2. Calculation of the calibration reference value After determining the existence of a systematic deviation, the system automatically initiates the correction calculation of the compensation benchmark value. A continuous value satisfying the above conditions is selected. Calculate the average deviation value of the hole position in the out-of-tolerance direction based on the positional deviation data of each batch. Correction amount The calculation formula is: / d Formula 14 in, The gain coefficient is set to a value between 0.3 and 0.7. The setting of this coefficient is based on the following considerations: instead of compensating completely according to the average deviation value, an "under-correction" strategy is adopted, which only corrects a part of the deviation. This can avoid over-correction caused by random factors in a single batch or measurement noise, so that the compensation value gradually and stably approaches the true value, and prevents the compensation value from oscillating greatly near the theoretical value. d is the theoretical coordinate distance of the hole position.

[0139] Corrected basic compensation reference value for: Formula 15 in, The correction amount is the current base compensation reference value. The sign (positive or negative) depends on the direction of the deviation—if the actual hole position deviates from the theoretical position in the positive direction, the compensation amount needs to be increased. If the deviation is positive, then the compensation amount needs to be reduced; conversely, if it deviates in the negative direction, then the compensation amount needs to be reduced. Take the negative value; the corrected reference value The compensation parameter table written into the CNC system will replace the original one. And it will take effect in the next batch of processing. The sign of ΔC can be determined according to the sign relationship between the position deviation direction and the theoretical coordinate X_(0,i) of the hole position: when the vector direction of the position deviation is the same as the vector direction from the origin to the theoretical coordinate point, it represents excessive expansion and the basic compensation reference value needs to be increased (ΔC takes positive); when the two directions are opposite, the basic compensation reference value needs to be decreased (ΔC takes negative).

[0140] 3. Correction Iteration and Safety Limits In subsequent batches of processing, the system continues to perform online detection and deviation analysis. If the deviation has fallen back to the tolerance range, the current compensation benchmark value is maintained unchanged, and the correction is completed. If the deviation is still not eliminated, but the trend condition is still met, the above correction calculation process is repeated, and the benchmark value is adjusted again.

[0141] To prevent abnormal drift of compensation values ​​due to abnormal causes such as sensor malfunction or machine tool hardware damage, the system sets safety limits for the basic compensation reference value in each direction. That is, the maximum and minimum allowable range of the benchmark value, when calculated. If the safety limit is exceeded, the system will not perform the update, but will immediately issue an alarm, indicating that there may be an abnormal situation requiring manual intervention.

[0142] 4. Data closed-loop recording Regardless of whether the correction is performed, the entire process of this out-of-tolerance analysis—including deviation data, trend judgment results, correction amount calculation, baseline values ​​before and after the update, and information such as whether safety limits are triggered—is recorded in the historical database with timestamps. This record provides process engineers with a complete traceability chain, supporting offline analysis and continuous optimization of correction strategies.

[0143] This mechanism enables the invention to automatically optimize the compensation model parameters based on the actual processing results, thereby forming a closed loop of "processing-compensation-detection-update", ensuring the high precision and high reliability of the compensation system in long-term operation, and effectively coping with changes in equipment status and seasonal fluctuations in ambient temperature.

[0144] Based on the same inventive concept, this application also provides an automatic feed boring machine for an RV reducer planetary carrier, including a controller, which is used to execute the above-described automatic feed boring method for an RV reducer planetary carrier.

[0145] This application also provides a computer-readable storage medium storing computer program instructions thereon, which, when executed by a processor, implement the steps of the automatic feed boring method for the planetary carrier of the RV reducer provided in this application.

[0146] In another exemplary embodiment, a computer program product is also provided, which includes a computer program executable by a programmable electronic device, the computer program having a code portion for performing the above-described automatic feed boring method for the planetary carrier of the RV reducer when executed by the programmable electronic device.

Claims

1. An automatic feed boring method for planetary carriers of RV reducers, characterized in that, The method includes: Acquire spindle vibration data and spindle load power during the machining process; The cutting state index is determined by linking the spindle vibration data and the spindle load power, and the feed rate is adaptively adjusted based on the cutting state index to control the rate of cutting heat generation. Based on the vibration trend offset and load trend offset in each machining operation, the tool wear state coefficient is obtained, and the U-axis extension of the boring tool is adjusted based on the tool wear state coefficient. Using the temperature difference between the current machining hole position and the reference hole position as input, and the tool wear state coefficient as the working condition correction factor, the total compensation coefficient is calculated and the actual machining coordinates are determined to perform boring machining. After machining is completed, online inspection is performed to verify the positional accuracy of the hole system and to form a data closed loop to optimize subsequent machining parameters.

2. The automatic feed boring method for the planetary carrier of an RV reducer according to claim 1, characterized in that, The spindle vibration data includes effective vibration values. The step of determining a cutting state index based on the spindle vibration data and the spindle load power, and adaptively adjusting the feed rate based on the cutting state index, includes: Obtain the warning threshold for vibration and the load safety threshold for load. The vibration exceedance ratio is obtained by the ratio of the effective vibration value to the warning threshold of the vibration dimension. The overload ratio is obtained based on the ratio of the spindle load power to the load safety threshold. The cutting state index is obtained based on the vibration over-limit ratio and the load over-limit ratio, and the graded feed rate adjustment is performed according to the interval of the cutting state index.

3. The automatic feed boring method for the planetary carrier of an RV reducer according to claim 2, characterized in that, The step of obtaining the cutting state index based on the vibration over-limit ratio and the load over-limit ratio includes: Obtain the current sampling period count and the preset sampling count threshold; The cutting state index is obtained based on the number of sampling cycles, the sampling count threshold, the vibration over-limit ratio, and the load over-limit ratio.

4. The automatic feed boring method for the planetary carrier of an RV reducer according to claim 2, characterized in that, The step of performing graded feed rate adjustment based on the range of the cutting state index includes: When the cutting state index is less than or equal to the first preset threshold and the load over-limit ratio is less than or equal to 1, the feed rate is set to a high-efficiency feed rate. When the cutting state index is greater than the first preset threshold and less than or equal to the second preset threshold, the feed rate is reduced to the standard feed rate. When the cutting state index is greater than the second preset threshold, the feed rate is forcibly reduced to the safe feed rate, the high-efficiency feed rate is greater than the standard feed rate, and the standard feed rate is greater than the safe feed rate.

5. The automatic feed boring method for the planetary carrier of an RV reducer according to claim 4, characterized in that, The step of performing graded feed rate adjustment based on the range of the cutting state index further includes: When the spindle load power reaches the load warning threshold of the load dimension, regardless of the value of the cutting state index, the feed rate is forcibly reduced to the safe feed rate, and the load warning threshold is greater than the load safety threshold. When the cutting state index falls below the first preset threshold and the load over-limit ratio is less than or equal to 1 and is maintained for a continuous sampling count threshold sampling period, the feed rate is gradually restored to the high-efficiency feed rate.

6. The automatic feed boring method for the planetary carrier of an RV reducer according to claim 1, characterized in that, The step of obtaining the tool wear state coefficient based on the vibration trend offset and load trend offset in each machining operation, and adjusting the U-axis extension of the boring tool based on the tool wear state coefficient, includes: When machining the first hole in the new tool state, obtain the first average vibration value and the first average load value during the smooth cutting stage; After machining the target hole, the second average vibration value and the second average load value during the smooth cutting phase of the target hole machining process are obtained, where the target hole is any machined hole after the first hole. The vibration trend deviation ratio is determined based on the ratio of the second vibration mean to the first vibration mean, and the load trend deviation ratio is determined based on the ratio of the second load mean to the first load mean. Based on the vibration trend offset ratio and the load trend offset ratio, the tool wear trend coefficient is obtained, and the tool wear trend coefficient is directly mapped to the tool wear state coefficient; The tool wear compensation amount is obtained based on the tool wear state coefficient, and the U-axis extension of the boring tool is adjusted based on the tool wear compensation amount.

7. The automatic feed boring method for the planetary carrier of an RV reducer according to claim 6, characterized in that, The process of obtaining the tool wear trend coefficient includes: Obtain the cumulative number of processed holes and the preset reference number of holes; The tool wear trend coefficient is obtained based on the cumulative value, the number of reference holes, the vibration trend offset ratio, and the load trend offset ratio.

8. The automatic feed boring method for the planetary carrier of an RV reducer according to claim 1, characterized in that, The calculation of the total compensation coefficient and determination of the actual machining coordinates for performing boring machining includes: The workpiece temperature at the moment the first hole is completed is used as the temperature reference, and the tool wear state coefficient at the moment the first hole is completed is used as the tool working condition reference. The difference between the workpiece temperature at the current hole position and the temperature reference is obtained, as well as the tool wear coefficient at the current hole position. The thermal expansion basic compensation coefficient is calculated based on the difference between the workpiece temperature at the current hole position and the temperature reference. The relative change factor is calculated based on the ratio of the tool wear state coefficient when machining the current hole position to the tool working condition reference, and the product of the thermal expansion basic compensation coefficient and the relative change factor is used as the total compensation coefficient. The actual machining coordinates of each hole are calculated based on the total compensation coefficient and the preset basic compensation reference value, and the actual machining coordinates are written into the interpolation command of the CNC system to perform boring.

9. The automatic feed boring method for the planetary carrier of an RV reducer according to claim 8, characterized in that, After the machining is completed, online testing is performed to verify the positional accuracy of the hole system and form a data closed loop, including: After all holes have been machined, when the workpiece temperature drops back to within the sum of the initial temperature and the cooling completion threshold, measure the actual coordinate position of each hole and calculate the positional deviation. If the positional deviation is within the preset tolerance range, the temperature rise curve, compensation record and test results of this processing will be written into the historical database. If the positional deviation exceeds the preset tolerance range, the deviation data is compared and analyzed with historical data. If the deviation shows a systematic trend, the basic compensation benchmark value is adjusted to form a closed-loop optimization of processing-compensation-detection-update.

10. An automatic feed boring machine for a planetary carrier of an RV reducer, characterized in that, The device includes a controller, the controller comprising: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the steps of the method according to any one of claims 1-9.

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