An EDM machine tool operation and maintenance method based on digital twin

Abstract

The present invention relates to the technical field of machine tool operation and maintenance, and specifically discloses an operation and maintenance method for an electric discharge machine tool based on digital twins. By obtaining the discharge parameters of the electric discharge machine tool when processing the same part of each part in the same batch, the discharge stability coefficient of the electric discharge machine tool when processing each part in the same batch is analyzed, and based on the discharge stability coefficient, it is identified whether the electric discharge machine tool has abnormal discharge behavior; if it is identified that the electric discharge machine tool has abnormal discharge behavior, the electric discharge machine tool is adjusted accordingly for operation and maintenance; at the same time, through the equipped electrode wear monitoring sensor, the initial volume of the electric discharge machine tool electrode when processing each part in the same batch is obtained in real time, and the wear rate of the electrode is analyzed by an algorithm. If the wear rate of the electrode is greater than the set wear threshold, the processing parameters of the electric discharge machine tool are automatically adjusted, which can significantly improve the operation and maintenance efficiency of the electric discharge machine tool, reduce production costs, and ensure product quality.

Description

Technical Field

[0001] The present invention belongs to the technical field of machine tool operation and maintenance, and relates to an electric spark machine tool operation and maintenance method based on digital twins. Background Art

[0002] EDM machines, which utilize electric spark discharge to erode materials, are widely used in mold manufacturing and complex parts processing. However, traditional EDM machines often experience poor machining quality or equipment damage during operation due to abnormal discharge conditions or severe electrode wear. These issues highlight the importance of EDM machine operation and maintenance management. However, current operation and maintenance technologies still have significant deficiencies and drawbacks in several areas:

[0003] First, traditional EDM machines lack real-time monitoring capabilities. Most rely on periodic inspections to identify problems, a method that is not only inefficient but also prone to delayed problem detection, making it impossible to promptly address risks posed by abnormal discharges or electrode wear. Furthermore, many machines lack intelligent sensors and data acquisition systems, making it impossible to acquire and analyze key discharge parameters in real time, making it impossible to dynamically adjust machining parameters to optimize the process.

[0004] Secondly, the maintenance strategy for many machine tools is still based on preventive maintenance at fixed intervals, rather than predictive maintenance based on equipment status. This approach cannot effectively prevent sudden failures and is prone to unplanned downtime and production interruptions. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the present invention provides an EDM machine tool operation and maintenance method based on digital twins to solve the above technical problems.

[0006] In order to achieve the above-mentioned and other purposes, the technical solutions adopted by the present invention are as follows:

[0007] A first aspect of the present invention provides an operation and maintenance method for an EDM machine tool based on digital twins, the method comprising the following steps:

[0008] Based on digital twin technology, a one-to-one model of the EDM machine tool is built to obtain a digital twin model of the EDM machine tool. The physical machine tool and the digital twin model are then connected through the Internet of Things technology.

[0009] The digital twin model of the EDM machine collects discharge parameters when processing the same part of each part in the same batch. It then analyzes the discharge stability coefficient of each part in the same batch and identifies abnormal discharge behavior based on the coefficient. If abnormal discharge behavior is identified, the EDM machine is adjusted accordingly.

[0010] The parts in the same batch are numbered in sequence. The initial volume of the EDM machine electrode during processing of each part in the same batch is monitored in real time through the electrode wear monitoring sensor equipped on the physical machine tool and sent to the digital twin model. The electrode wear rate is analyzed through an algorithm. If the electrode wear rate is greater than the set wear threshold, the processing parameters of the EDM machine are automatically adjusted.

[0011] The analysis logic for analyzing the discharge stability coefficient of EDM machines when processing parts in the same batch is as follows:

[0012] Based on the discharge parameters of the EDM machine when processing the same part of each part in the same batch, the voltage, current, pulse duration and pulse interval of the EDM machine when processing the same part of each part in the same batch are extracted and marked in sequence. Instead, j is the number of each part in the same batch, j=1,2,...J, J represents the total number of parts in the same batch;

[0013] The comprehensive index of discharge parameters of each part of the EDM machine tool is calculated from this , The specific calculation formula is shown as follows:

[0014] ;

[0015] In the above formula They represent the mean voltage, mean current, mean pulse duration and mean pulse interval of the EDM machine when processing the same part of the same batch of parts. They represent the voltage standard deviation, current standard deviation, pulse duration standard deviation and pulse interval standard deviation of the EDM machine when processing the same part of the parts in the same batch; ω1, ω2, ω3 and ω4 represent the set voltage calculation weight, current calculation weight, pulse duration calculation weight and pulse interval calculation weight respectively;

[0016] The environmental parameters corresponding to each part in the same batch of EDM machine tools are collected synchronously. The environmental parameters are divided into temperature and humidity, which are recorded as ;

[0017] Substitute the temperature and humidity corresponding to each part in the same batch processed by the EDM machine into the calculation formula of the environmental impact factor of each part in the same batch processed by the EDM machine to obtain the environmental impact factor of each part in the same batch processed by the EDM machine , where WD and SD represent the standard ambient temperature and standard ambient humidity respectively, α1, α2 and α3 represent the set temperature influence coefficient, humidity influence coefficient and temperature-humidity interaction influence coefficient respectively;

[0018] Finally, based on the comprehensive index of discharge parameters of EDM machine tools corresponding to each part and the environmental impact factor, the discharge stability coefficient of EDM machine tools in processing each part in the same batch is comprehensively analyzed. .

[0019] Identify whether the EDM machine tool has abnormal discharge behavior. The specific identification logic is:

[0020] Based on the discharge stability coefficient of EDM machine tools in processing parts in the same batch Then, the discharge stability average value and discharge stability standard deviation of the EDM machine tool in processing parts in the same batch are calculated and recorded as ;

[0021] The upper and lower thresholds for abnormality detection are set for EDM machines when processing parts in the same batch. The specific setting process is as follows:

[0022] ;

[0023] ;

[0024] in and They represent the upper and lower thresholds for abnormality detection of parts in the same batch processed by the EDM machine tool, respectively. k is a set calculation constant, which sets the sensitivity for detection.

[0025] Then identify the authenticity of discharge anomalies of EDM machines in processing parts in the same batch ;

[0026] The total number of true discharge anomalies corresponding to parts in the same batch processed by the EDM machine is counted as the numerator of the fraction, and the total number of parts in the same batch is used as the denominator of the fraction. The fraction is solved to obtain the discharge anomaly ratio of parts in the same batch processed by the EDM machine;

[0027] The discharge abnormality ratio of the EDM machine tool when processing parts in the same batch is compared with the set allowable abnormality ratio. If the former is greater than the latter, it is determined that the EDM machine tool has abnormal discharge behavior; otherwise, it is determined that the EDM machine tool does not have abnormal discharge behavior.

[0028] Make corresponding operation and maintenance adjustments to the EDM machine. The specific adjustment logic is as follows:

[0029] Based on the voltage, current, pulse duration, and pulse interval of the EDM machine tool when processing the same part of each part in the same batch, the Z-score method is used to determine the abnormal type of abnormal discharge behavior of the EDM machine tool. The abnormal types are specifically divided into voltage abnormality, current abnormality, pulse duration abnormality, and pulse interval abnormality.

[0030] If the abnormal discharge behavior of the EDM machine tool is identified as voltage abnormality, the voltage threshold range is determined according to the processing requirements of the same part of the part. , and the iterative adjustment formula for the corresponding voltage operation and maintenance adjustment of the EDM machine tool is calculated as follows: ;

[0031] In the above formula, △DY is the voltage deviation value. , DY' is the voltage target value, is the set voltage adjustment step value, Iteratively adjust the voltage value for the corresponding voltage operation and maintenance adjustment of the EDM machine;

[0032] The iterative adjustment voltage value of the EDM machine tool for corresponding voltage operation and maintenance adjustment is equal to If the difference between the iteratively adjusted voltage value of the EDM machine tool corresponding to the voltage operation and maintenance adjustment and the voltage target value is not within the set difference allowable range, a second or even multiple iterations will be performed until the difference between the iteratively adjusted voltage value of the EDM machine tool corresponding to the voltage operation and maintenance adjustment and the voltage target value is within the set difference allowable range;

[0033] If the abnormal discharge behavior of the EDM machine is identified as abnormal current, abnormal pulse duration or abnormal pulse interval, the current operation, pulse duration or pulse interval operation of the EDM machine is adjusted accordingly according to the corresponding voltage operation and maintenance adjustment method of the EDM machine.

[0034] The Z-score method is used to determine the abnormal type of abnormal discharge behavior in EDM machines. The specific determination process includes:

[0035] Obtain the voltage of the EDM machine when processing the same part of each part in the same batch, and then use the Z-score method to calculate the mean Z-score of the voltage of the EDM machine when processing the parts in the same batch ;

[0036] Then determine the authenticity of the EDM machine in the corresponding voltage anomaly , k1 is the set voltage Z-score calculation constant;

[0037] If the calculation result of the authenticity of the corresponding voltage anomaly of the EDM machine is , then it is determined that the abnormal type of abnormal discharge behavior of the EDM machine tool is voltage abnormality;

[0038] Based on the calculation method for determining the authenticity of the corresponding voltage anomaly of the EDM machine, the authenticity of the corresponding current anomaly, pulse duration anomaly and pulse interval anomaly of the EDM machine can be determined in the same way;

[0039] If the authenticity of the corresponding current anomaly of the EDM machine is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine is determined to be current anomaly;

[0040] If the authenticity of the EDM machine tool in the corresponding pulse continuous abnormality is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine tool is determined to be pulse continuous abnormality;

[0041] If the authenticity of the EDM machine tool in the corresponding pulse interval abnormality is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine tool is determined to be pulse interval abnormality;

[0042] Based on the above judgment process, the abnormal type of abnormal discharge behavior of the EDM machine tool can be comprehensively determined.

[0043] The wear rate of the electrode is analyzed by an algorithm, including:

[0044] The initial volume of the EDM machine electrode in processing the parts in the same batch is recorded as , j is the number of each part in the same batch;

[0045] The total time t spent by the EDM machine in processing the same batch of parts is recorded simultaneously, and the electrode wear rate is calculated from this , J represents the total number of parts in the same batch, It represents the initial volume of the EDM machine electrode when processing the j-1th part in the same batch, and τ is the set error correction value.

[0046] The machining parameters of the electric spark machine tool are discharge gap, pulse width, working fluid pressure and electrode feed speed.

[0047] Automatically adjust the discharge gap and pulse width of the EDM machine. The specific adjustment process is as follows:

[0048] Obtain the electrode wear rate η;

[0049] Calculate the adjustment value of the discharge gap of the EDM machine tool ;

[0050] Calculate the pulse width adjustment value corresponding to the EDM machine tool ;

[0051] In the above formula They are the current value of the discharge gap and the current value of the pulse width of the EDM machine tool respectively. Wear adjustment threshold set for the electrode, The maximum permissible threshold value of the wear rate set for the electrode, λ1 and λ2 represent the set adjustment coefficients, which are used to control the adjustment amplitude.

[0052] Automatically adjust the working fluid pressure and electrode feed speed of the EDM machine. The specific adjustment process is as follows:

[0053] Calculate the adjustment value of the corresponding working hydraulic pressure of the EDM machine ;

[0054] Calculate the adjustment value of the electrode feed speed corresponding to the EDM machine tool ;

[0055] In the above formula are the current values ​​of the working hydraulic pressure and electrode feed speed of the EDM machine tool respectively. λ3 and λ4 represent the set adjustment coefficients, which are used to control the adjustment range.

[0056] A second aspect of the present invention provides an EDM machine tool operation and maintenance device based on digital twins, comprising a processor, a memory, and a communication bus;

[0057] The memory stores a computer-readable program executable by the processor;

[0058] The communication bus realizes the connection and communication between the processor and the memory;

[0059] When the processor executes the computer-readable program, the steps in the above-mentioned digital twin-based EDM machine operation and maintenance method are implemented.

[0060] The third aspect of the present invention provides a computer-readable storage medium, which stores one or more programs. The one or more programs can be executed by one or more processors to implement the steps in the above-mentioned digital twin-based EDM machine operation and maintenance method.

[0061] As described above, the digital twin-based EDM machine tool operation and maintenance method provided by the present invention has at least the following beneficial effects:

[0062] (1) The embodiment of the present invention can effectively evaluate the discharge stability of the EDM machine tool by monitoring and analyzing the discharge parameters of each part in the same batch of parts, and then identify whether there is abnormal discharge behavior. The necessity of this process is that abnormal discharge will not only lead to a decrease in processing accuracy, but may also cause equipment damage, increase production costs and downtime. Therefore, timely identification and adjustment of abnormal discharge behavior is an important link to ensure the normal operation of the equipment. The analysis of the discharge stability coefficient can provide information about the consistency and reliability of the discharge of the EDM machine tool during the processing process. By comparing the discharge parameters of parts in the same batch, potential abnormal fluctuations can be found. Such fluctuations may be caused by uneven electrode wear, unstable working fluid pressure or equipment failure. After identifying these anomalies, the EDM machine tool can be immediately adjusted for operation and maintenance to restore the stability and accuracy of the processing.

[0063] (2) The embodiment of the present invention is equipped with an electrode wear monitoring sensor to obtain the initial volume of the electrode and calculate the wear rate in real time, making the management of the electrode more scientific and efficient. When the electrode wear rate is detected to exceed the set threshold, the system can automatically adjust the processing parameters, such as reducing the discharge current, optimizing the pulse width, or increasing the discharge gap, to extend the service life of the electrode. This adaptive adjustment not only improves the utilization rate of the electrode, but also reduces the processing defects and downtime caused by electrode wear.

[0064] (3) The embodiments of the present invention can significantly improve the operation and maintenance efficiency of EDM machines, reduce production costs, and ensure product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0066] Figure 1 It is a schematic diagram of the connection of each step of the method of the present invention. DETAILED DESCRIPTION

[0067] The above contents described below in conjunction with the implementation of the present invention are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

[0068] Example 1

[0069] See also Figure 1As shown, an EDM machine tool operation and maintenance method based on digital twins includes the following steps:

[0070] Based on digital twin technology, a one-to-one model of the EDM machine tool is built to obtain a digital twin model of the EDM machine tool. The physical machine tool and the digital twin model are then connected through the Internet of Things technology.

[0071] The digital twin model of the EDM machine collects discharge parameters when processing the same part of each part in the same batch. It then analyzes the discharge stability coefficient of each part in the same batch and identifies abnormal discharge behavior based on the coefficient. If abnormal discharge behavior is identified, the EDM machine is adjusted accordingly.

[0072] In the preferred technical solution of this application, the analysis logic for the discharge stability coefficient of the EDM machine tool is as follows:

[0073] Based on the discharge parameters of the EDM machine when processing the same part of each part in the same batch, the voltage, current, pulse duration and pulse interval of the EDM machine when processing the same part of each part in the same batch are extracted and marked in sequence. Instead, j is the number of each part in the same batch, j=1,2,...J, J represents the total number of parts in the same batch;

[0074] The comprehensive index of discharge parameters of each part of the EDM machine tool is calculated from this , The specific calculation formula is shown as follows:

[0075] ;

[0076] In the above formula They represent the mean voltage, mean current, mean pulse duration and mean pulse interval of the EDM machine when processing the same part of the same batch of parts. They represent the voltage standard deviation, current standard deviation, pulse duration standard deviation, and pulse interval standard deviation of the EDM machine when processing the same part of the parts in the same batch; ω1, ω2, ω3, and ω4 represent the set voltage calculation weight, current calculation weight, pulse duration calculation weight, and pulse interval calculation weight, respectively, and ω1+ω2+ω3+ω4=1 must also be satisfied;

[0077] Indicates the actual current during the discharge process, measured in amperes (A). In EDM, current directly affects machining efficiency and surface finish. Higher currents generally increase machining speed but may result in reduced surface quality. Indicates the degree of current fluctuation during the entire machining process. If the standard deviation is large, it means that the current fluctuation is large and the machining is unstable;

[0078] Usually measured in volts (V), the voltage affects the formation of the discharge gap and the transfer of discharge energy. A stable voltage contributes to uniform processing, but large voltage fluctuations may lead to unstable discharge. Indicates the degree of voltage fluctuation;

[0079] Indicates the duration of each discharge, usually in microseconds. The longer the pulse duration, the greater the discharge energy per unit time, which helps to improve the material removal rate, but may cause the heat affected area to increase;

[0080] Indicates the time interval between two discharges, usually in microseconds. The shorter the pulse interval, the faster the processing speed, but it may lead to unstable processing (such as discharge short circuit or over-discharge).

[0081] The environmental parameters corresponding to each part in the same batch of EDM machine tools are collected synchronously. The environmental parameters are divided into temperature and humidity, which are recorded as ;

[0082] Substitute the temperature and humidity corresponding to each part in the same batch processed by the EDM machine into the calculation formula of the environmental impact factor of each part in the same batch processed by the EDM machine to obtain the environmental impact factor of each part in the same batch processed by the EDM machine , where WD and SD represent the standard ambient temperature and standard ambient humidity respectively, α1, α2 and α3 represent the set temperature influence coefficient, humidity influence coefficient and temperature-humidity interaction influence coefficient respectively;

[0083] The temperature influence coefficient α1 indicates the degree of influence of temperature on the discharge process; temperature changes will affect the dielectric properties of the discharge gap, thereby affecting the stability of the discharge; higher temperatures may cause increased evaporation of the dielectric, affecting the discharge efficiency and processing accuracy;

[0084] The humidity influence coefficient α2 indicates the degree of influence of humidity on the discharge process. Humidity changes will affect the conductivity of air and medium, thereby affecting the discharge characteristics of the discharge gap. Higher humidity may cause an increase in moisture in the medium, affecting the stability of the discharge process.

[0085] The temperature-humidity interaction coefficient α3 indicates the degree of influence of the combined effects of temperature and humidity on the discharge process. The interaction between temperature and humidity may amplify or weaken the effect of a single factor. For example, in a high temperature and high humidity environment, the physical properties of the medium may change significantly, affecting the discharge stability.

[0086] Finally, based on the comprehensive index of discharge parameters of EDM machine tools corresponding to each part and the environmental impact factor, the discharge stability coefficient of EDM machine tools in processing each part in the same batch is comprehensively analyzed. .

[0087] In the preferred technical solution of this application, it is possible to identify whether the EDM machine tool has abnormal discharge behavior. The specific identification logic is as follows:

[0088] Based on the discharge stability coefficient of EDM machine tools in processing parts in the same batch Then, the discharge stability average value and discharge stability standard deviation of the EDM machine tool in processing parts in the same batch are calculated and recorded as ;

[0089] The upper and lower thresholds for abnormality detection are set for EDM machines when processing parts in the same batch. The specific setting process is as follows:

[0090] ;

[0091] ;

[0092] in and They represent the upper and lower thresholds for abnormality detection of parts in the same batch processed by the EDM machine tool, respectively. k is a set calculation constant that sets the sensitivity for detection. The value of k is usually 2 or 3. The specific meanings are as follows:

[0093] When k=2, the detection range is two times the standard deviation of the mean, which is suitable for situations where you want to detect more anomalies. When k=3, the detection range is three times the standard deviation of the mean, which is suitable for situations where you only want to detect obvious anomalies. By adjusting the value of k, you can control the sensitivity and false alarm rate of anomaly detection.

[0094] Then identify the authenticity of discharge anomalies of EDM machines in processing parts in the same batch ;

[0095] The total number of true discharge anomalies corresponding to parts in the same batch processed by the EDM machine is counted as the numerator of the fraction, and the total number of parts in the same batch is used as the denominator of the fraction. The fraction is solved to obtain the discharge anomaly ratio of parts in the same batch processed by the EDM machine;

[0096] The discharge abnormality ratio of the EDM machine when processing parts in the same batch is compared with the set allowable abnormality ratio. If the former is greater than the latter, it is determined that the EDM machine has abnormal discharge behavior; otherwise, it is determined that the EDM machine does not have abnormal discharge behavior; the former refers to the discharge abnormality ratio of the EDM machine when processing parts in the same batch, and the latter refers to the set allowable abnormality ratio.

[0097] In the preferred technical solution of this application, the EDM machine tool is adjusted for operation and maintenance accordingly, and the specific adjustment logic is as follows:

[0098] Based on the voltage, current, pulse duration, and pulse interval of the EDM machine tool when processing the same part of each part in the same batch, the Z-score method is used to determine the abnormal type of abnormal discharge behavior of the EDM machine tool. The abnormal types are specifically divided into voltage abnormality, current abnormality, pulse duration abnormality, and pulse interval abnormality.

[0099] If the abnormal discharge behavior of the EDM machine tool is identified as voltage abnormality, the voltage threshold range is determined according to the processing requirements of the same part of the part. , and the iterative adjustment formula for the corresponding voltage operation and maintenance adjustment of the EDM machine tool is calculated as follows: ;

[0100] In the above formula, △DY is the voltage deviation value. , DY' is the voltage target value, is the set voltage adjustment step value, Iteratively adjust the voltage value for the corresponding voltage operation and maintenance adjustment of the EDM machine;

[0101] The specific steps for determining the voltage threshold range and setting the adjustment voltage step value mentioned above are as follows: First, according to the processing requirements and material properties, a detailed process analysis is required, including research on the electrical conductivity, thermal conductivity and response characteristics of the processed material to EDM. In combination with the technical parameters of the equipment and the recommended operating manual, a voltage threshold range suitable for the process is formulated. Usually, preliminary data can be obtained through experiments and multiple processing verifications can be performed to optimize the range; secondly, when setting the adjustment voltage step value, the sensitivity and processing accuracy of the equipment should be considered to select a suitable step size. It is generally recommended to start with a smaller step size, such as 1-5V. According to the response speed of the equipment to voltage changes and the feedback of processing quality, the step size is gradually adjusted to ensure that no excessive fluctuations are caused during the adjustment process. At the same time, precise control can be achieved, thereby ensuring the stability of the processing process and product quality;

[0102] The iterative adjustment voltage value of the EDM machine tool for corresponding voltage operation and maintenance adjustment is equal to If the difference between the iteratively adjusted voltage value of the EDM machine tool corresponding to the voltage operation and maintenance adjustment and the voltage target value is not within the set difference allowable range, a second or even multiple iterations will be performed until the difference between the iteratively adjusted voltage value of the EDM machine tool corresponding to the voltage operation and maintenance adjustment and the voltage target value is within the set difference allowable range;

[0103] If the abnormal discharge behavior of the EDM machine is identified as abnormal current, abnormal pulse duration or abnormal pulse interval, the current operation, pulse duration or pulse interval operation of the EDM machine is adjusted accordingly according to the corresponding voltage operation and maintenance adjustment method of the EDM machine.

[0104] In the preferred technical solution of this application, the Z-score method is used to determine the abnormal type of abnormal discharge behavior of the EDM machine tool. The specific determination process includes:

[0105] Obtain the voltage of the EDM machine when processing the same part of each part in the same batch, and then use the Z-score method to calculate the mean Z-score of the voltage of the EDM machine when processing the parts in the same batch ;

[0106] Then determine the authenticity of the EDM machine in the corresponding voltage anomaly , k1 is the set voltage Z-score calculation constant;

[0107] If the calculation result of the authenticity of the corresponding voltage anomaly of the EDM machine is , then it is determined that the abnormal type of abnormal discharge behavior of the EDM machine tool is voltage abnormality;

[0108] Based on the calculation method for determining the authenticity of the corresponding voltage anomaly of the EDM machine, the authenticity of the corresponding current anomaly, pulse duration anomaly and pulse interval anomaly of the EDM machine can be determined in the same way;

[0109] If the authenticity of the corresponding current anomaly of the EDM machine is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine is determined to be current anomaly;

[0110] If the authenticity of the EDM machine tool in the corresponding pulse continuous abnormality is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine tool is determined to be pulse continuous abnormality;

[0111] If the authenticity of the EDM machine tool in the corresponding pulse interval abnormality is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine tool is determined to be pulse interval abnormality;

[0112] Based on the above judgment process, the abnormal type of abnormal discharge behavior of the EDM machine tool can be comprehensively determined.

[0113] The parts in the same batch are numbered in sequence. The initial volume of the EDM machine electrode during processing of each part in the same batch is monitored in real time through the electrode wear monitoring sensor equipped on the physical machine tool and sent to the digital twin model. The electrode wear rate is analyzed through an algorithm. If the electrode wear rate is greater than the set wear threshold, the processing parameters of the EDM machine are automatically adjusted.

[0114] In the preferred technical solution of this application, the wear rate of the electrode is analyzed by an algorithm, including:

[0115] The initial volume of the EDM machine electrode in processing the parts in the same batch is recorded as , j is the number of each part in the same batch;

[0116] The total time t spent by the EDM machine in processing the same batch of parts is recorded simultaneously, and the electrode wear rate is calculated from this , J represents the total number of parts in the same batch, It represents the initial volume of the EDM machine electrode when processing the j-1th part in the same batch, and τ is the set error correction value.

[0117] In a preferred technical solution of the present application, the machining parameters of the electric spark machine are discharge gap, pulse width, working fluid pressure and electrode feed speed.

[0118] When the electrode wear rate exceeds the set wear threshold, the EDM machine parameters (including discharge gap, pulse width, working fluid pressure, and electrode feed speed) are adjusted to optimize the machining process, extend electrode life, and ensure machining quality. These four parameters are selected based on their direct impact on the discharge process and electrode wear:

[0119] First, the discharge gap is the distance between the electrode and the workpiece during the discharge process. An appropriate discharge gap can ensure stable discharge conditions and reduce excessive wear of the electrode. When the wear rate is too high, increasing the discharge gap can reduce the contact frequency between the electrode and the workpiece, thereby reducing wear;

[0120] Secondly, the pulse width determines the duration of each discharge. Adjusting the pulse width can affect the discharge energy, which in turn affects the material removal rate and the degree of electrode wear. Shortening the pulse width can reduce the discharge energy and reduce electrode wear.

[0121] The working fluid pressure has a significant impact on the chip removal and cooling effect within the discharge gap. Properly increasing the working fluid pressure can more effectively remove the debris generated by the discharge, prevent electrode wear caused by secondary discharge, and improve the cooling effect, reducing thermal wear of the electrode.

[0122] Finally, the electrode feed speed controls the rate at which the electrode is fed into the workpiece. Properly adjusting the feed speed ensures that the electrode operates within the appropriate discharge gap and avoids excessive contact between the electrode and the workpiece due to excessive feeding, which increases wear.

[0123] In summary, these four parameters directly influence EDM discharge conditions, energy transfer, and thermal management. By adjusting these parameters, it is possible to optimize the machining environment when wear rates are excessive, reduce electrode wear, and improve machining quality and efficiency. This adjustment strategy not only extends electrode life but also ensures process stability and controllability.

[0124] In the preferred technical solution of this application, the discharge gap and pulse width of the EDM machine are automatically adjusted. The specific adjustment process is as follows:

[0125] Obtain the electrode wear rate η;

[0126] Calculate the adjustment value of the discharge gap of the EDM machine tool , using the logarithmic function log can achieve smooth adjustment and avoid drastic changes;

[0127] Calculate the pulse width adjustment value corresponding to the EDM machine tool , using an exponential function to quickly respond to large wear differences;

[0128] In the above formula They are the current value of the discharge gap and the current value of the pulse width of the EDM machine tool respectively. Wear adjustment threshold set for the electrode, The maximum permissible threshold value of the wear rate set for the electrode, λ1 and λ2 represent the set adjustment coefficients, which are used to control the adjustment amplitude.

[0129] In the preferred technical solution of this application, the working fluid pressure and electrode feed speed of the EDM machine are automatically adjusted. The specific adjustment process is as follows:

[0130] Calculate the adjustment value of the corresponding working hydraulic pressure of the EDM machine , using the sine function sin, to provide nonlinear adjustment;

[0131] Calculate the adjustment value of the electrode feed speed corresponding to the EDM machine tool , using the hyperbolic tangent function to limit extreme adjustments;

[0132] In the above formula are the current values ​​of the working hydraulic pressure and electrode feed speed of the EDM machine, respectively. λ3 and λ4 represent the set adjustment coefficients, which are used to control the adjustment amplitude. tanh(·) represents the hyperbolic tangent function.

[0133] In the above formula, λ1, λ2, λ3 and λ4 usually take values ​​between 0 and 1;

[0134] The wear adjustment threshold of the electrode setting in the above calculation formula and the maximum permissible threshold of the wear rate set by the electrode The specific meanings are as follows:

[0135] Wear adjustment threshold for electrode settings This is a target value used to determine when machining parameters need to be adjusted. If the electrode wear rate exceeds this value, it means that adjustments need to be made to optimize the machining process.

[0136] Maximum permissible threshold for electrode wear rate setting This is a limit value, indicating the maximum acceptable range of electrode wear rate. Exceeding this value may lead to reduced processing quality or equipment damage. It is used in the formula to normalize and calculate the adjustment range to ensure that the adjustment is carried out within a safe range.

[0137] In summary, is a trigger point, and It’s a safety boundary.

[0138] Example 2

[0139] An EDM machine tool operation and maintenance device based on digital twin, comprising a processor, a memory, and a communication bus;

[0140] The memory stores a computer-readable program executable by the processor;

[0141] The communication bus realizes the connection and communication between the processor and the memory;

[0142] When the processor executes the computer-readable program, the steps in the above-mentioned digital twin-based EDM machine operation and maintenance method are implemented.

[0143] Example 3

[0144] A computer-readable storage medium stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps in the above-mentioned digital twin-based EDM machine operation and maintenance method.

[0145] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0146] It should be understood that determining B based on A does not mean determining B based solely on A. B can also be determined based on A and / or other information.

[0147] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0148] Finally: 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, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An EDM machine tool operation and maintenance method based on digital twin, characterized in that: The steps include: Based on digital twin technology, a one-to-one model of the EDM machine tool is built to obtain a digital twin model of the EDM machine tool. The physical machine tool and the digital twin model are then connected through the Internet of Things technology. The digital twin model of the EDM machine tool collects the discharge parameters of the EDM machine tool when processing the same part of each part in the same batch. The discharge stability coefficient of the EDM machine tool when processing each part in the same batch is analyzed, and based on this, it is identified whether the EDM machine tool has abnormal discharge behavior; If abnormal discharge behavior is detected on the EDM machine, corresponding operation and maintenance adjustments will be made to the EDM machine; The analysis logic for analyzing the discharge stability coefficient of EDM machines when processing parts in the same batch is as follows: Based on the discharge parameters of the EDM machine when processing the same part of each part in the same batch, the voltage, current, pulse duration and pulse interval of the EDM machine when processing the same part of each part in the same batch are extracted and marked in sequence. Instead, j is the number of each part in the same batch, j=1,2,...J, J represents the total number of parts in the same batch; The comprehensive index of discharge parameters of each part of the EDM machine tool is calculated from this , The specific calculation formula is shown as follows: ； In the above formula They represent the mean voltage, mean current, mean pulse duration and mean pulse interval of the EDM machine when processing the same part of the same batch of parts. They represent the voltage standard deviation, current standard deviation, pulse duration standard deviation and pulse interval standard deviation of the EDM machine when processing the same part of the parts in the same batch; ω1, ω2, ω3 and ω4 represent the set voltage calculation weight, current calculation weight, pulse duration calculation weight and pulse interval calculation weight respectively; The environmental parameters corresponding to each part in the same batch of EDM machine tools are collected synchronously. The environmental parameters are divided into temperature and humidity, which are recorded as ; Substitute the temperature and humidity corresponding to each part in the same batch processed by the EDM machine into the calculation formula of the environmental impact factor of each part in the same batch processed by the EDM machine to obtain the environmental impact factor of each part in the same batch processed by the EDM machine , where WD and SD represent the standard ambient temperature and standard ambient humidity respectively, α1, α2 and α3 represent the set temperature influence coefficient, humidity influence coefficient and temperature-humidity interaction influence coefficient respectively; Finally, based on the comprehensive index of discharge parameters of EDM machine tools corresponding to each part and the environmental impact factor, the discharge stability coefficient of EDM machine tools in processing each part in the same batch is comprehensively analyzed. ; Identify whether the EDM machine tool has abnormal discharge behavior. The specific identification logic is: Based on the discharge stability coefficient of EDM machine tools in processing parts in the same batch Then, the discharge stability average value and discharge stability standard deviation of the EDM machine tool in processing parts in the same batch are calculated and recorded as ; The upper and lower thresholds for abnormality detection are set for EDM machines when processing parts in the same batch. The specific setting process is as follows: ； ； in and They represent the upper and lower thresholds for abnormality detection of parts in the same batch processed by the EDM machine tool, respectively. k is a set calculation constant, which sets the sensitivity for detection. Then identify the authenticity of discharge anomalies of EDM machines in processing parts in the same batch ； The total number of true discharge anomalies corresponding to parts in the same batch processed by the EDM machine is counted as the numerator of the fraction, and the total number of parts in the same batch is used as the denominator of the fraction. The fraction is solved to obtain the discharge anomaly ratio of parts in the same batch processed by the EDM machine; Compare the discharge abnormality ratio of the EDM machine tool when processing parts in the same batch with the set allowable abnormality ratio. If the former is greater than the latter, it is determined that the EDM machine tool has abnormal discharge behavior; otherwise, it is determined that the EDM machine tool does not have abnormal discharge behavior. Make corresponding operation and maintenance adjustments to the EDM machine. The specific adjustment logic is as follows: Based on the voltage, current, pulse duration, and pulse interval of the EDM machine tool when processing the same part of each part in the same batch, the Z-score method is used to determine the abnormal type of abnormal discharge behavior of the EDM machine tool. The abnormal types are specifically divided into voltage abnormality, current abnormality, pulse duration abnormality, and pulse interval abnormality. If the abnormal discharge behavior of the EDM machine tool is identified as voltage abnormality, the voltage threshold range is determined according to the processing requirements of the same part of the part. , and the iterative adjustment formula for the corresponding voltage operation and maintenance adjustment of the EDM machine tool is calculated as follows: ; In the above formula, △DY is the voltage deviation value. , DY' is the voltage target value, is the set voltage adjustment step value, Iteratively adjust the voltage value for the corresponding voltage operation and maintenance adjustment of the EDM machine; The iterative adjustment voltage value of the EDM machine tool for corresponding voltage operation and maintenance adjustment is equal to If the difference between the iteratively adjusted voltage value of the EDM machine tool corresponding to the voltage operation and maintenance adjustment and the voltage target value is not within the set difference allowable range, a second or even multiple iterations will be performed until the difference between the iteratively adjusted voltage value of the EDM machine tool corresponding to the voltage operation and maintenance adjustment and the voltage target value is within the set difference allowable range; If the abnormal discharge behavior of the EDM machine tool is identified as abnormal current, abnormal pulse duration, or abnormal pulse interval, the current operation, pulse duration, or pulse interval operation of the EDM machine tool is adjusted accordingly according to the above-mentioned voltage operation and maintenance adjustment method; The parts in the same batch are numbered in sequence. The initial volume of the EDM machine electrode during processing of each part in the same batch is monitored in real time through the electrode wear monitoring sensor equipped on the physical machine tool and sent to the digital twin model. The electrode wear rate is analyzed through an algorithm. If the electrode wear rate is greater than the set wear threshold, the processing parameters of the EDM machine are automatically adjusted.

2. The method for operating and maintaining an EDM machine tool based on digital twin according to claim 1, characterized in that: The Z-score method is used to determine the abnormal type of abnormal discharge behavior in EDM machines. The specific determination process includes: Obtain the voltage of the EDM machine when processing the same part of each part in the same batch, and then use the Z-score method to calculate the mean Z-score of the voltage of the EDM machine when processing the parts in the same batch ; Then determine the authenticity of the EDM machine in the corresponding voltage anomaly , k1 is the set voltage Z-score calculation constant; If the calculation result of the authenticity of the corresponding voltage anomaly of the EDM machine is , then it is determined that the abnormal type of abnormal discharge behavior of the EDM machine tool is voltage abnormality; Based on the calculation method for determining the authenticity of the corresponding voltage anomaly of the EDM machine, the authenticity of the corresponding current anomaly, pulse duration anomaly and pulse interval anomaly of the EDM machine can be determined in the same way; If the authenticity of the corresponding current anomaly of the EDM machine is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine is determined to be current anomaly; If the authenticity of the EDM machine tool in the corresponding pulse continuous abnormality is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine tool is determined to be pulse continuous abnormality; If the authenticity of the EDM machine tool in the corresponding pulse interval abnormality is expressed as True, then the abnormal type of abnormal discharge behavior of the EDM machine tool is determined to be pulse interval abnormality; Based on the above judgment process, the abnormal type of abnormal discharge behavior of the EDM machine tool can be comprehensively determined.

3. The operation and maintenance method of an EDM machine tool based on digital twin according to claim 1, characterized in that: The wear rate of the electrode is analyzed by an algorithm, including: The initial volume of the EDM machine electrode in processing the parts in the same batch is recorded as , j is the number of each part in the same batch; The total time t spent by the EDM machine in processing the same batch of parts is recorded simultaneously, and the electrode wear rate is calculated from this , J represents the total number of parts in the same batch, It represents the initial volume of the EDM machine electrode when processing the j-1th part in the same batch, and τ is the set error correction value.

4. The method for operating and maintaining an EDM machine tool based on digital twin according to claim 1, characterized in that: The machining parameters of the electric spark machine tool are discharge gap, pulse width, working fluid pressure and electrode feed speed.

5. The method for operating and maintaining an EDM machine tool based on digital twin according to claim 4, characterized in that: Automatically adjust the discharge gap and pulse width of the EDM machine. The specific adjustment process is as follows: Obtain the electrode wear rate η; Calculate the adjustment value of the discharge gap of the EDM machine tool ; Calculate the pulse width adjustment value corresponding to the EDM machine tool ; In the above formula They are the current value of the discharge gap and the current value of the pulse width of the EDM machine tool respectively. Wear adjustment threshold set for the electrode, The maximum permissible threshold value of the wear rate set for the electrode, λ1 and λ2 represent the set adjustment coefficients, which are used to control the adjustment amplitude.

6. The method for operating and maintaining an EDM machine tool based on digital twin according to claim 5, characterized in that: Automatically adjust the working fluid pressure and electrode feed speed of the EDM machine. The specific adjustment process is as follows: Calculate the adjustment value of the corresponding working hydraulic pressure of the EDM machine ; Calculate the adjustment value of the electrode feed speed corresponding to the EDM machine tool ; In the above formula are the current values ​​of the working hydraulic pressure and electrode feed speed of the EDM machine tool respectively. λ3 and λ4 represent the set adjustment coefficients, which are used to control the adjustment range.

7. An EDM machine tool operation and maintenance device based on digital twin, characterized by: It is implemented based on an EDM machine tool operation and maintenance method based on digital twin according to any one of claims 1 to 6, comprising a processor, a memory and a communication bus; The memory stores a computer-readable program executable by the processor; The communication bus realizes the connection and communication between the processor and the memory; When the processor executes the computer-readable program, it implements an EDM machine tool operation and maintenance method based on digital twin as described in any one of claims 1 to 6.

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