Machining state monitoring method and device for numerical control system

Abstract

The invention discloses a machining state monitoring method and device for a numerical control system, and relates to the technical field of machining state monitoring. The use state (tool apparent value) of the tool can be monitored in real time and quickly reflected by calling the tool image and carrying out gray processing, pixel statistics and other operations; the method comprises the following steps: acquiring and analyzing cutting force, cutting speed, amplitude and temperature of each part of a machine tool, and calculating to obtain influence factors; comprehensive analysis is carried out on the apparent value and the influence factor of the cutter to obtain a cutter state value, a curve graph of the cutter state value changing along with time is constructed, predictive monitoring analysis is carried out according to the curve graph to judge the state of the cutter, the replacement strategy of the cutter is intelligently adjusted, and intelligent, scientific and automatic cutter replacement is achieved; the cutter state change can be responded in time, the machining process is ensured to be carried out smoothly, and the product quality and the production efficiency are guaranteed to the maximum extent.

Description

Technical Field

[0001] The present invention relates to the technical field of machining state monitoring, and in particular to a machining state monitoring method and device for a numerical control system. Background Art

[0002] Numerical Control System (CNC) is an automated system that controls machine tools and other manufacturing equipment through computer programs. It uses pre-programmed instructions to control the movement of tools and machine tools to achieve high-precision processing of complex parts. In the CNC processing process, the tool is particularly important, and the tool directly determines the roughness, shape accuracy and dimensional accuracy of the processed surface. The tools used in current CNC systems are usually replaced when they reach a preset service life. However, the fixed-time tool replacement strategy has limitations. If the tool is replaced prematurely before its service life is completely exhausted within the preset period, it will lead to waste of resources and increased costs. Especially for high-cost tools or large processing equipment, too high a replacement frequency will significantly increase production costs. Summary of the invention

[0003] The main purpose of the present invention is to provide a machining state monitoring method and method for a numerical control system to overcome the problems mentioned in the above background technology.

[0004] To achieve the above object, according to one aspect of the present invention, a method for monitoring machining status for a numerical control system is provided, the method comprising the following steps: Step 1: Collect and save processing information by communicating with the CNC system; the processing information includes tool image, cutting force, cutting speed, amplitude, and temperature of various parts of the machine tool; Step 2: Perform real-time monitoring and analysis based on tool graphics to obtain tool appearance values; Step 3: Monitor and analyze the impact of the tool based on the processing information to obtain the impact factor; Step 4: Perform a comprehensive analysis based on the tool's apparent value and influencing factors to determine whether the tool needs to be replaced; specifically: The tool appearance value and influencing factor corresponding to each acquisition moment are retrieved, and the tool appearance value is divided by the influencing factor to obtain the tool state value recorded as ZFi, and the tool state value is used as the horizontal coordinate and the tool state value is used as the vertical coordinate to obtain a curve graph of the tool state value changing with time; a tangent line is drawn at the state point, and the tangent expression is obtained by data fitting, and the state derivative of each state point is obtained by derivative operation on the tangent expression and recorded as Ui, where i=1, 2, 3...I, and I is a positive integer, I represents the total number of acquisition moments, and i represents the sequence number of any acquisition moment; When the absolute value of the state derivative is greater than the upper limit of the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is in the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is greater than the lower limit of the variation interval, a low tool loss is accumulated; the accumulated number of high tool loss, medium tool loss and low tool loss is counted and recorded as P1, P2 and P3 respectively; Obtain the tool state value corresponding to the current acquisition moment and record it as ZF, and substitute it with the cumulative number of high loss P1, the cumulative number of medium loss P2, the cumulative number of low loss P3, and the state derivative Ui into the set formula The loss index Pn is calculated, where n1, n2, and n3 are respectively set proportional coefficients, and n1>n2>n3>0; When the loss index is greater than or equal to the set loss threshold, a tool change instruction is generated to control the tool retraction operation and replace the new tool.

[0005] Furthermore, the specific process of real-time monitoring and analysis based on tool graphics is as follows: 201: retrieve the tool image corresponding to each acquisition time, use the photo identifier to identify the tool image, and perform grayscale processing on it; divide the grayscale processed blade image into a number of squares, count the number of pixels in each square and record it as Gk, where k=, 2, 3...K, K is a positive integer, K represents the total number of squares, and k represents the sequence number of any square; take the center point of each square, calculate its shortest distance to the edge of the tool blade and record it as Lk; 202: Identify pixel points and horizontal gradients and vertical gradients corresponding to each pixel point, calculate the horizontal gradient and vertical gradient using the Sobel operator to obtain the gradient amplitude corresponding to each pixel point, and compare and analyze them to obtain the clarity value of the grid; 203: Substitute the number of pixels Gk, the shortest distance Lk and the clarity value Tak of the grid into the set formula Calculate to obtain the sharpness value Rb of each grid, wherein b1, b2, and b3 are respectively set proportional coefficients, and the values ​​thereof are set by those skilled in the art according to actual needs. Grids with the same shortest distance are grouped together, and the sharpness values ​​of the grids in the group are averaged to obtain the sharpness mean; thus, the sharpness mean of each group can be obtained, and the groups are numbered in descending order according to the shortest distance of each group, thus obtaining the number of each group; 203: The tool sharpness change curve is obtained by taking the number as the horizontal axis and the sharpness mean as the vertical axis, and the tool sharpness mean change trend is analyzed based on this to obtain the tool apparent value.

[0006] Furthermore, the specific steps for comparing and analyzing the gradient amplitudes corresponding to each pixel point are as follows: Compare and analyze the gradient amplitude of each pixel point in the grid with the set amplitude range to divide the pixel points corresponding to the gradient amplitude into high-definition points, medium-definition points and low-definition points; count the cumulative number of high-definition points, medium-definition points and low-definition points in the grid respectively, and record them as T1, T2, and T3 respectively; sum the gradient amplitudes corresponding to the high-definition points, medium-definition points and low-definition points to obtain high-definition values, medium-definition values ​​and low-definition values, and record them as T4, T5, and T6 respectively; Substitute T1, T2, T3, T4, T5, and T6 into the set formula The clarity value Ta of the grid is obtained by calculation, wherein a1, a2, and a3 are respectively set proportional coefficients, and a1>a2>a3>0, and the value is set by those skilled in the art according to actual needs.

[0007] Furthermore, the specific steps for analyzing the trend of tool sharpness mean are as follows: Draw tangents of the curve at each sharp point, use the tangent expression of data fitting, and derive the tangent expression to obtain the tangent derivatives of each sharp point. Sum the tangent derivatives greater than zero to obtain the increasing value, recorded as Z1; count the number of tangent derivatives equal to zero, recorded as Z2, and count the number of tangent derivatives less than zero, recorded as Z3, sum the tangent derivatives less than zero and take the absolute value to calculate the decreasing degree, recorded as Z4; use the set formula The tool apparent value Zd is calculated, where d1, d2, d3, and d4 are respectively set proportional coefficients, and their values ​​are set by technical personnel in this field according to actual needs; thus, the tool apparent value corresponding to each acquisition moment is recorded as Zdi.

[0008] Furthermore, the specific process of monitoring and analyzing the impact of machining information on the tool is as follows: 501: Retrieve the cutting force, cutting speed, amplitude, and temperature of each part of the machine tool corresponding to each acquisition moment; 502: Set a sensitivity coefficient corresponding to each part of the machine tool, compare each part of the machine tool with all the set parts of the machine tool to match the corresponding sensitivity coefficient, multiply the temperature of each part of the machine tool by the corresponding sensitivity coefficient to obtain a temperature sensitivity value recorded as Mqi, and compare and analyze it to obtain a temperature sensitivity influence value, where q=1, 2, 3...Q, Q is a positive integer, Q represents the total number of machine tool parts, and q represents the serial number of any part in the machine tool; 503: The cutting force Fi, cutting speed Vi, amplitude Ai and temperature sensitivity influence value Ygi are calculated by the set formula The influence factor FYi is calculated, where h1, h2, h3, and h4 are respectively the set proportional coefficients; thus, the influence factor corresponding to each acquisition moment can be obtained.

[0009] Furthermore, the specific process of comparative analysis of the temperature sensitivity values ​​is as follows: The temperature sensitivity value is compared with the set temperature sensitivity range to divide the parts of the machine tool corresponding to the temperature sensitivity value into high-impact parts, medium-impact parts and low-impact parts, and the cumulative number of high-impact parts, medium-impact parts and low-impact parts in the machine tool is counted respectively, and recorded as Y1, Y2, and Y3 respectively; Substitute the cumulative number of high-impact parts Y1, the cumulative number of medium-impact parts Y2, the cumulative number of low-impact parts Y3 and the temperature sensitivity value Mqi of each part of the machine tool into the set formula The temperature-sensitive influence value Ygi is calculated, where g1, g2, and g3 are respectively set proportional coefficients, and g1>g2>g3>0.

[0010] In order to achieve the above object, according to another aspect of the present invention, a machining state monitoring device for a numerical control system is provided, the device comprising: a data acquisition module, a state monitoring module and a machining control module; The data acquisition module communicates with the numerical control system to collect and save processing information, wherein the processing information includes tool image, cutting force, cutting speed, amplitude, and temperature of various parts of the machine tool; The condition monitoring module performs real-time monitoring and analysis based on the tool graphics to obtain the tool appearance value. At the same time, it monitors and analyzes the impact of the tool based on the processing information to obtain the impact factor. The machining control module performs a comprehensive analysis based on the tool apparent value and influencing factors to determine whether the tool needs to be replaced; specifically: The tool appearance value and influencing factor corresponding to each acquisition moment are retrieved, and the tool appearance value is divided by the influencing factor to obtain the tool state value recorded as ZFi, and the tool state value is used as the horizontal coordinate and the tool state value is used as the vertical coordinate to obtain a curve graph of the tool state value changing with time; a tangent line is drawn at the state point, and the tangent expression is obtained by data fitting, and the state derivative of each state point is obtained by derivative operation on the tangent expression and recorded as Ui, where i=1, 2, 3...I, and I is a positive integer, I represents the total number of acquisition moments, and i represents the sequence number of any acquisition moment; When the absolute value of the state derivative is greater than the upper limit of the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is in the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is greater than the lower limit of the variation interval, a low tool loss is accumulated; the accumulated number of high tool loss, medium tool loss and low tool loss is counted and recorded as P1, P2 and P3 respectively; Obtain the tool state value corresponding to the current acquisition moment and record it as ZF, and substitute it with the cumulative number of high loss P1, the cumulative number of medium loss P2, the cumulative number of low loss P3, and the state derivative Ui into the set formula The loss index Pn is calculated, where n1, n2, and n3 are respectively set proportional coefficients, and n1>n2>n3>0; When the loss index is greater than or equal to the set loss threshold, a tool change instruction is generated to control the tool retraction operation and replace the new tool.

[0011] Beneficial effects of the present invention: (1) The present invention can monitor and quickly respond to the tool usage status (tool apparent value) in real time by retrieving tool images and performing grayscale processing, pixel statistics and other operations, providing detailed analysis and monitoring of the tool usage status, achieving in-depth analysis and accurate evaluation of the tool status, and providing important technical support and decision-making basis for tool management in industrial production; (2) The present invention collects and analyzes the cutting force, cutting speed, amplitude and the temperature of each part of the machine tool to calculate the influencing factor, which can accurately reflect the actual influence of the machine tool working conditions on the tool, realize real-time monitoring of the tool use environment, and make the tool management more scientific and efficient; (3) By constructing a curve graph showing the change of tool status value over time, the present invention enables the staff to understand the working status of the tool in real time, including the consumption of its service life, and to promptly discover abnormal changes or rapid consumption of the tool during use. Based on this, the present invention can conduct predictive monitoring and analysis to determine the status of the tool and intelligently adjust the tool replacement strategy, thereby avoiding the waste of premature replacement, extending the tool service life to the greatest extent, and reducing the overall procurement and maintenance costs of the tool. The present invention realizes intelligent, scientific and automated tool replacement, can promptly respond to tool status changes, ensure the smooth progress of the processing process, and maximize product quality and production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 It is a schematic flow chart of the method of the present invention; Figure 2 It is a schematic diagram of the device of the present invention. DETAILED DESCRIPTION

[0013] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0014] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0015] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present invention described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0016] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] According to an embodiment of the present invention, Figure 1 As shown, a method for monitoring machining status for a numerical control system is provided, the method comprising the following steps: Step 1: Collect and save processing information by communicating with the CNC system; the processing information includes tool image, cutting force, cutting speed, amplitude (amplitude of machine tool vibration), and temperature of various parts of the machine tool; Step 2: Based on the tool image, the tool usage status is monitored and analyzed in real time to obtain the tool apparent value, specifically: Retrieve the tool image corresponding to each acquisition moment; use the photo identifier to identify the tool image and perform grayscale processing on it; divide the grayscale processed blade image into several squares, count the number of pixels in each square and record it as Gk, where k=, 2, 3...K, K is a positive integer, K represents the total number of squares, and k represents the sequence number of any square; take the center point of each square, calculate its shortest distance to the edge of the tool blade and record it as Lk; it should be noted that, under normal circumstances, the closer the square is to the edge of the blade, the more pixels the corresponding square should have, because the blade is sharper; when the tool is worn and the blade is not sharp, the number of corresponding square pixels close to the edge is smaller; Identify the pixel points and the horizontal and vertical gradients corresponding to each pixel point, and use the Sobel operator to calculate the horizontal and vertical gradients to obtain the gradient amplitude corresponding to each pixel point; it should be noted that the larger the gradient amplitude of the pixel point, the clearer the pixel point is, and the smaller the gradient amplitude is, the more blurred it is; compare and analyze the gradient amplitude of each pixel point in the grid with the set amplitude range. When the gradient amplitude is greater than the set upper limit of the amplitude range, a high-definition point is accumulated; when the gradient amplitude is in the set amplitude range, a medium-definition point is accumulated; when the gradient amplitude is less than the set lower limit of the amplitude range, a low-definition point is accumulated; count the cumulative number of high-definition points, medium-definition points and low-definition points in the grid respectively, and record them as T1, T2, and T3 respectively; sum the gradient amplitudes corresponding to high-definition points, medium-definition points and low-definition points to obtain high-definition values, medium-definition values ​​and low-definition values, and record them as T4, T5, and T6 respectively; use the set formula The clarity value Ta of the grid is obtained by calculation, wherein a1, a2, and a3 are respectively set proportional coefficients, and a1>a2>a3>0, and the values ​​are set by those skilled in the art according to actual needs; thus, the clarity value of each grid is recorded as Tak; The number of pixels Gk, the shortest distance Lk and the clarity value Tak of the grid are calculated by the formula Calculate to obtain the sharpness value Rb of each grid, wherein b1, b2, and b3 are respectively set proportional coefficients, and the values ​​thereof are set by those skilled in the art according to actual needs; group the grids with the same shortest distance into one group, and calculate the average of the sharpness values ​​of the grids in the group to obtain the sharpness mean; thereby, the sharpness mean of each group can be obtained, and the groups are numbered in descending order according to the shortest distance of each group, thereby obtaining the number of each group; construct a two-dimensional rectangular coordinate system with the number as the horizontal coordinate and the sharpness mean as the vertical coordinate, and input the sharpness mean into the coordinate axis according to its corresponding number, and input the sharpness mean into the coordinate axis. The position of the mean in the coordinate axis is recorded as the sharp point, and a smooth curve is used to connect the sharp points in sequence to obtain a tool sharpness change curve. It should be noted that when the tool is in normal condition (no wear or very little wear, which does not affect the processing and can be ignored), the sharp mean should be a curve that increases accordingly. This is because the closer the distance to the edge of the blade, the sharper it should be. Correspondingly, if the blade is worn, if the blade of the tool is worn and the blade becomes blunt, then the squares closer to the edge of the blade may show a lower sharp mean, because the distribution of pixels around the edge is no longer obvious and the clarity is reduced. Draw tangents of the curve at each sharp point, use the tangent expression of data fitting, and derive the tangent expression to obtain the tangent derivatives of each sharp point. Sum the tangent derivatives greater than zero to obtain the increasing value, recorded as Z1; count the number of tangent derivatives equal to zero, recorded as Z2, and count the number of tangent derivatives less than zero, recorded as Z3, sum the tangent derivatives less than zero and take the absolute value to calculate the decreasing degree, recorded as Z4; use the set formula The tool apparent value Zd is obtained by calculation, wherein d1, d2, d3, and d4 are respectively set proportional coefficients, and the values ​​thereof are set by technicians in the field according to actual needs; thus, the tool apparent value corresponding to each acquisition moment is recorded as Zdi, wherein i=1, 2, 3...I, I is a positive integer, I represents the total number of acquisition moments, and i represents the sequence number of any one of the acquisition moments; it can be seen from the formula that the sharper the tool, the greater the tool apparent value; By retrieving the tool image and performing grayscale processing, pixel statistics and other operations, it is possible to monitor the tool usage status (tool apparent value) in real time and quickly respond to it, provide detailed analysis and monitoring of the tool usage status, achieve in-depth analysis and accurate evaluation of the tool status, and provide important technical support and decision-making basis for tool management in industrial production.

[0018] Step 3: Based on the influence of machining information on tool usage, real-time monitoring and analysis are performed to obtain the influencing factors, specifically: The cutting force, cutting speed, amplitude, and temperature of each part of the machine tool corresponding to each acquisition moment are retrieved (the machine tool is divided into several parts, and the temperature of each part is collected), and they are recorded as Fi, Vi, Ai, and Wqi, respectively, where q=1, 2, 3...Q, Q is a positive integer, Q represents the total number of machine tool parts, and q represents the serial number of any part in the machine tool; Set a sensitivity coefficient for each part of the machine tool. It should be noted that different parts of the machine tool are affected by temperature to different degrees due to different functions and working conditions. Therefore, a specific sensitivity coefficient needs to be set for each part. These sensitivity coefficients reflect the degree of influence of each part on the overall performance of the tool when the temperature changes. For example, the tool guide part of the machine tool is more sensitive to temperature changes, because temperature changes will directly affect the accuracy and stability of the tool, and thus affect the processing quality, while other parts of the machine tool, such as the casing or auxiliary structure, are less responsive to temperature changes, so their sensitivity coefficients are set to lower values. Set the sensitivity coefficients of each part of the machine tool to the same value. The part is compared with all the set machine tool parts to match the corresponding sensitivity coefficient, and the temperature of each part of the machine tool is multiplied by the corresponding sensitivity coefficient to obtain the temperature sensitivity value, and it is recorded as Mqi; the temperature sensitivity value is compared and analyzed with the set temperature sensitivity interval. When the temperature sensitivity value is greater than the set upper limit of the temperature sensitivity interval, a high-impact part is accumulated; when the temperature sensitivity value is in the set temperature sensitivity interval, a medium-impact part is accumulated; when the temperature sensitivity value is greater than the set upper limit of the temperature sensitivity interval, a low-impact part is accumulated; the cumulative number of high-impact parts, medium-impact parts and low-impact parts in the machine tool are counted respectively, and they are recorded as Y1, Y2, and Y3 respectively; using the set formula The temperature-sensitive influence value Ygi is calculated, where g1, g2, and g3 are respectively the set proportional coefficients, and g1>g2>g3>0; The cutting force Fi, cutting speed Vi, amplitude Ai and temperature sensitivity influence value Ygi are calculated by the formula The influence factor FYi is calculated, where h1, h2, h3, and h4 are respectively the set proportional coefficients; thus, the influence factor corresponding to each acquisition moment can be obtained; from the formula, it can be seen that when the temperature-sensitive influence value is larger, it means that the machine tool temperature has a greater negative interference on the tool accuracy, and the influence factor is larger; when the cutting force and cutting speed are larger, it means that the tool is used more frequently and the cutting volume is larger, the negative interference on the tool wear and heat is greater, and the influence factor is larger; the specific reasons are: high cutting force and cutting speed will lead to increased tool wear, especially the cutting edge of the tool, because high-speed cutting will increase the friction and heat on the tool surface, and accelerate the wear of the tool blade; high cutting force and cutting speed will generate a lot of heat, which will cause deformation of the tool material or reduce the surface hardness, thereby affecting the tool life and processing quality; when the machine tool amplitude is larger, it will accelerate the fatigue wear of the tool, especially for the tool blade, which will cause early wear and failure of the cutting edge and reduce the service life of the tool; By collecting and analyzing the cutting force, cutting speed, amplitude and temperature of various parts of the machine tool, the influencing factors are calculated, which can accurately reflect the actual impact of the machine tool working conditions on the tool, realize real-time monitoring of the tool use environment, and make tool management more scientific and efficient.

[0019] Step 4: Perform a comprehensive analysis based on the tool apparent value and influencing factors to determine whether the tool needs to be replaced, so as to achieve intelligent, scientific and automated tool replacement; specifically: The tool apparent value Zdi and influencing factor FYi at each acquisition time are retrieved, and the tool apparent value is divided by the influencing factor to obtain the tool state value recorded as ZFi. A two-dimensional rectangular coordinate system is constructed with time as the horizontal coordinate and the tool state value as the vertical coordinate. The tool state value is input into the coordinate axis according to its corresponding acquisition time, and the position of the state value in the coordinate axis is recorded as the state point. A smooth curve is used to connect the state points in sequence to obtain a curve chart of the tool state value changing with time; a tangent line is drawn at the state point, and a tangent expression is obtained by data fitting. The state derivative of each state point is obtained by derivation of the tangent expression and recorded as Ui. Since the tool state value will only become smaller and smaller with the use of time, the state derivatives are all less than zero; Compare and analyze the absolute value of the state derivative with the variation interval. When the absolute value of the state derivative is greater than the upper limit of the variation interval, a high tool loss is accumulated once; when the absolute value of the state derivative is in the variation interval, a high tool loss is accumulated once; when the absolute value of the state derivative is greater than the lower limit of the variation interval, a low tool loss is accumulated once; the accumulated number of high tool loss, medium tool loss and low tool loss is counted and recorded as P1, P2 and P3 respectively; Get the tool status value corresponding to the current acquisition time, record it as ZF, and use the set formula The loss index Pn is calculated, where n1, n2, and n3 are respectively the set proportional coefficients, and n1>n2>n3>0; the loss index is compared and analyzed with the set loss threshold. When the loss index is greater than or equal to the set loss threshold, it means that the tool state has accumulated to have a relatively large negative impact on the processing, resulting in a high risk of the precision of the processed parts not meeting the requirements, and the tool needs to be replaced; then a tool replacement instruction is generated to control the tool track to withdraw (tool retraction operation) and replace a new tool to ensure the smooth progress of the processing process and the stability of product quality; By constructing a curve chart showing the tool status value changing over time, the staff can understand the working status of the tool in real time, including the consumption of its service life, and promptly discover abnormal changes or rapid consumption during the use of the tool. Based on this, they can conduct predictive monitoring and analysis to determine the status of the tool and intelligently adjust the tool replacement strategy to avoid the waste of premature replacement, maximize the tool life, and reduce the overall procurement and maintenance costs of the tool. It can also achieve intelligent, scientific and automated tool replacement, respond to tool status changes in a timely manner, ensure the smooth progress of the machining process, and maximize product quality and production efficiency.

[0020] According to an embodiment of the present invention, Figure 2 As shown, a processing state monitoring device for a numerical control system is also provided, the device comprising: a data acquisition module, a state monitoring module and a processing control module; The data acquisition module communicates with the numerical control system to collect and save processing information, wherein the processing information includes tool image, cutting force, cutting speed, amplitude, and temperature of various parts of the machine tool; The condition monitoring module performs real-time monitoring and analysis based on the tool graphics to obtain the tool appearance value. At the same time, it monitors and analyzes the impact of the tool based on the processing information to obtain the impact factor. The machining control module performs a comprehensive analysis based on the tool apparent value and influencing factors to determine whether the tool needs to be replaced; specifically: The tool appearance value and influencing factor corresponding to each acquisition moment are retrieved, and the tool appearance value is divided by the influencing factor to obtain the tool state value recorded as ZFi, and the tool state value is used as the horizontal coordinate and the tool state value is used as the vertical coordinate to obtain a curve graph of the tool state value changing with time; a tangent line is drawn at the state point, and the tangent expression is obtained by data fitting, and the state derivative of each state point is obtained by derivative operation on the tangent expression and recorded as Ui, where i=1, 2, 3...I, and I is a positive integer, I represents the total number of acquisition moments, and i represents the sequence number of any acquisition moment; When the absolute value of the state derivative is greater than the upper limit of the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is in the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is greater than the lower limit of the variation interval, a low tool loss is accumulated; the accumulated number of high tool loss, medium tool loss and low tool loss is counted and recorded as P1, P2 and P3 respectively; Obtain the tool state value corresponding to the current acquisition moment and record it as ZF, and substitute it with the cumulative number of high loss P1, the cumulative number of medium loss P2, the cumulative number of low loss P3, and the state derivative Ui into the set formula The loss index Pn is calculated, where n1, n2, and n3 are respectively set proportional coefficients, and n1>n2>n3>0; When the loss index is greater than or equal to the set loss threshold, a tool change instruction is generated to control the tool retraction operation and replace the new tool.

[0021] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A machining state monitoring method for a numerical control system, characterized in that: The following steps are involved: Step 1: Collect and save processing information by communicating with the CNC system; the processing information includes tool image, cutting force, cutting speed, amplitude, and temperature of various parts of the machine tool; Step 2: Perform real-time monitoring and analysis based on tool graphics to obtain tool appearance values; Step 3: Monitor and analyze the impact of the tool based on the processing information to obtain the impact factor; Step 4: Perform a comprehensive analysis based on the tool's apparent value and influencing factors to determine whether the tool needs to be replaced; specifically: The tool appearance value and influencing factor corresponding to each acquisition moment are retrieved, and the tool state value corresponding to each acquisition moment is calculated by formulating the value, and a curve graph of tool state value changing with time is obtained with time as the horizontal coordinate and tool state value as the vertical coordinate; a tangent line is drawn at the state point, and a tangent line expression is obtained by data fitting, and the state derivative of each state point is obtained by derivation of the tangent line expression; When the absolute value of the state derivative is greater than the upper limit of the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is in the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is greater than the lower limit of the variation interval, a low tool loss is accumulated; the accumulated number of high tool loss, medium tool loss and low tool loss is counted; Obtain the tool state value corresponding to the current acquisition moment, normalize it with the cumulative number of high losses, the cumulative number of medium losses, the cumulative number of low losses, and the state derivative, and take their values, and analyze the values ​​to obtain the loss index; When the loss index is greater than or equal to the set loss threshold, a tool change instruction is generated to control the tool retraction operation and replace the new tool.

2. A method for monitoring machining status for a numerical control system according to claim 1, characterized in that: The specific process of real-time monitoring and analysis based on tool graphics is as follows: 201: Retrieving the tool image corresponding to each acquisition moment, using a photo recognizer to recognize the tool image, and grayscale processing it; dividing the grayscale processed blade image into a number of squares, counting the number of pixels in each square; taking the center point of each square, and calculating the shortest distance between it and the edge of the tool blade; 202: Identify pixel points and horizontal gradients and vertical gradients corresponding to each pixel point, calculate the horizontal gradient and vertical gradient using the Sobel operator to obtain the gradient amplitude corresponding to each pixel point, and compare and analyze them to obtain the clarity value of the grid; 203: normalize the number of pixels, the shortest distance and the clarity value of the square and take the values ​​thereof, analyze the values ​​to obtain the sharpness value of each square, group the squares with the same shortest distance into one group, and calculate the average of the sharpness values ​​of the squares in the group to obtain the sharpness mean; thereby obtaining the sharpness mean of each group, and labeling the groups in descending order according to the shortest distance of each group, thereby obtaining the label of each group; 203: The tool sharpness change curve is obtained by taking the number as the horizontal axis and the sharpness mean as the vertical axis, and the tool sharpness mean change trend is analyzed based on this to obtain the tool apparent value.

3. A method for monitoring machining status for a numerical control system according to claim 2, characterized in that: The specific steps for comparing and analyzing the gradient amplitude corresponding to each pixel point are: Compare and analyze the gradient amplitude of each pixel point in the grid with the set amplitude range to divide the pixel points corresponding to the gradient amplitude into high-definition points, medium-definition points and low-definition points; count the cumulative number of high-definition points, medium-definition points and low-definition points in the grid respectively, and sum the gradient amplitudes corresponding to the high-definition points, medium-definition points and low-definition points to obtain high-definition values, medium-definition values ​​and low-definition values ​​respectively; The cumulative number of high-definition points, the cumulative number of medium-definition points, the cumulative number of low-definition points, the high-definition value, the medium-definition value and the low-definition value are analyzed to obtain the clarity value of the grid, thereby obtaining the clarity value of each grid.

4. A method for monitoring machining status for a numerical control system according to claim 3, characterized in that: The specific steps for analyzing the trend of tool sharpness mean are as follows: Draw tangents of the curve at each sharp point, use the tangent expression of data fitting, and derive the tangent expression to obtain the tangent derivatives of each sharp point. Sum the tangent derivatives greater than zero to obtain the increasing value, recorded as Z1; count the number of tangent derivatives equal to zero, recorded as Z2, and count the number of tangent derivatives less than zero, recorded as Z3, sum the tangent derivatives less than zero and take the absolute value to calculate the decreasing degree, recorded as Z4; use the set formula The tool apparent value Zd is calculated, where d1, d2, d3, and d4 are respectively set proportional coefficients, and their values ​​are set by technical personnel in this field according to actual needs; thus, the tool apparent value corresponding to each acquisition moment is recorded as Zdi, where i=1, 2, 3...I, I represents the total number of acquisition moments, and i represents the sequence number of any acquisition moment.

5. The method for monitoring machining status for a numerical control system according to claim 1, characterized in that: The specific process of monitoring and analyzing the impact of machining information on the tool is as follows: 501: Retrieve the cutting force, cutting speed, amplitude, and temperature of each part of the machine tool corresponding to each acquisition moment; 502: Set a sensitivity coefficient for each part of the machine tool, compare each part of the machine tool with all the set parts of the machine tool to match the corresponding sensitivity coefficient, multiply the temperature of each part of the machine tool by the corresponding sensitivity coefficient to obtain the temperature sensitivity value, and compare and analyze it to obtain the temperature sensitivity influence value; 503: The cutting force, cutting speed, amplitude and temperature sensitivity influence values ​​are normalized and their values ​​are taken, and the influencing factors are obtained by numerical analysis.

6. A method for monitoring machining status for a numerical control system according to claim 5, characterized in that: The specific process of comparative analysis of temperature sensitivity values ​​is as follows: Compare and analyze the temperature sensitivity value with the set temperature sensitivity range to divide the parts of the machine tool corresponding to the temperature sensitivity value into high-impact parts, medium-impact parts and low-impact parts, and count the cumulative number of high-impact parts, medium-impact parts and low-impact parts in the machine tool respectively; The cumulative number of high-impact parts, the cumulative number of medium-impact parts, the cumulative number of low-impact parts and the temperature-sensitive values ​​of each part of the machine tool are analyzed to obtain the temperature-sensitive impact value.

7. A machining status monitoring device for a numerical control system, characterized in that A method for monitoring machining status for a numerical control system according to any one of claims 1 to 6, the device comprising: a data acquisition module, a status monitoring module and a machining control module; The data acquisition module communicates with the numerical control system to collect and save processing information, wherein the processing information includes tool image, cutting force, cutting speed, amplitude, and temperature of various parts of the machine tool; The condition monitoring module performs real-time monitoring and analysis based on the tool graphics to obtain the tool appearance value. At the same time, it monitors and analyzes the impact of the tool based on the processing information to obtain the impact factor. The machining control module performs a comprehensive analysis based on the tool apparent value and influencing factors to determine whether the tool needs to be replaced; specifically: The tool appearance value and influencing factor corresponding to each acquisition moment are retrieved, and the tool state value corresponding to each acquisition moment is calculated by formulating the value, and a curve graph of tool state value changing with time is obtained with time as the horizontal coordinate and tool state value as the vertical coordinate; a tangent line is drawn at the state point, and a tangent line expression is obtained by data fitting, and the state derivative of each state point is obtained by derivation of the tangent line expression; When the absolute value of the state derivative is greater than the upper limit of the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is in the variation interval, a high tool loss is accumulated; when the absolute value of the state derivative is greater than the lower limit of the variation interval, a low tool loss is accumulated; the accumulated number of high tool loss, medium tool loss and low tool loss is counted; Obtain the tool state value corresponding to the current acquisition moment, normalize it with the cumulative number of high losses, the cumulative number of medium losses, the cumulative number of low losses, and the state derivative, and take their values, and analyze the values ​​to obtain the loss index; When the loss index is greater than or equal to the set loss threshold, a tool change instruction is generated to control the tool retraction operation and replace the new tool.

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