A method and system for matching dynamic characteristics of a numerical control machine tool for efficient cutting and machining path planning

Abstract

The application discloses a kind of high-efficiency cutting-oriented dynamic characteristics matching and machining path planning method and system of numerical control machine tool, and it is related to intelligent manufacturing and numerical control machining path optimization technical field, the method includes the following steps: based on the CAD three-dimensional drawing of machining part, CAD three-dimensional drawing is imported into CAM software, the machining surface and non-machining surface of part are determined, and a plurality of machining schemes and process parameters of different machining surfaces of part are generated by CAM software in combination with drawing parameter requirements;The machining scheme under the process parameter of the different machining surface generated is combined with the part material data, the machining stiffness, vibration parameter is calculated, and the standard stiffness, vibration parameter of current numerical control machine tool is collected.The tool path planning and process parameters in CAM programming process are matched by combining the dynamic performance of numerical control machine tool, and the clothing is tailored according to the different machine numerical control programming, and the clothing is tailored according to the different machine numerical control programming.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent manufacturing and CNC machining path optimization, and relates to computer-aided manufacturing, dynamic modeling of CNC machine tools, and tool path planning technology. Specifically, it relates to a method and system for dynamic characteristic matching and machining path planning of CNC machine tools for efficient cutting, which is used to improve the matching degree between the machining path and the machine tool performance, and enhance machining stability and precision. Background Art

[0002] CNC machine tools are computer-controlled machines that achieve automated machining. They offer high precision, efficiency, and flexibility, making them widely used in a variety of high-end manufacturing fields, including aerospace, automotive, precision molds, and medical devices. Typical CNC machining systems utilize pre-programmed programs, including G-codes and M-codes, to automatically control tool motion, speed, feed rate, and other parameters, thereby achieving complex machining tasks.

[0003] However, existing CNC machine tools often generate machining paths based on a 3D CAD drawing of the part, combined with preset machining strategies in CAM software. This process primarily focuses on part geometry, and process parameters are often based on empirical values ​​or material library recommendations. However, different CNC machine tools have varying characteristics, including machine stiffness, vibration, acceleration, and electrical system response speed. Existing machining path planning simply selects machining plans for each machining surface based on the drawing requirements. It fails to tailor tool path planning and process parameters during CAM programming to the characteristics of individual machine tools, resulting in limited practicality and functionality. For example, machine tools with insufficient stiffness are prone to structural deformation during high-speed milling or heavy-load cutting, leading to dimensional errors. When the tool excitation frequency approaches the natural frequency of the machine tool structure, chatter is easily induced, severely impacting surface quality and tool life. Furthermore, the response time of the electrical control system to motion commands varies between machine tools, potentially causing following errors or servo lag in highly dynamic path sections, reducing machining accuracy.

[0004] In the prior art, Chinese patent CN107710084B discloses a processing path planning method, which inserts a continuous curvature clothoid transition when adjacent line segments are switched to reduce the jump of acceleration and jerk values ​​during CNC machine tool processing. However, this method only focuses on the smooth transition of the geometric path and ignores the influence of the dynamic performance of the machine tool itself on the processing process. CN118605381A discloses a processing path planning method for a CNC machine tool, which performs surface topology analysis through workpiece surface scanning data, constructs a spatiotemporal dynamic model of cutting force, and performs dynamic path correction. However, this method focuses on the perception of workpiece surface features and the modeling of the cutting process, and the consideration of the dynamic characteristics of the machine tool itself is still not in-depth enough, and relies on complex sensor systems and calculation models, and the implementation cost is high.

[0005] Furthermore, current machining path optimization primarily focuses on single-objective optimization (e.g., shortest path, minimum machining time), lacking a multi-dimensional, comprehensive optimization mechanism based on real-world physical performance modeling. This mismatch between tool paths and machine tool dynamics is particularly prominent in high-performance machining and efficient cutting scenarios, severely hindering further improvements in machining efficiency.

[0006] In summary, existing CNC machining path planning technologies have yet to effectively integrate the dynamic characteristics of machine tools, making it difficult to achieve coordinated optimization of machining plans and equipment capabilities. This leads to significant challenges such as insufficient machining stability, large path execution deviations, and limited machining accuracy. Therefore, accurately matching machining paths with machine tool dynamics, and improving the adaptability of path planning and the dynamic stability of the machining process, are pressing technical challenges in the field of CNC machining path planning. Summary of the Invention

[0007] (1) Purpose of the invention

[0008] In response to the above-mentioned defects and shortcomings in the prior art, the present invention aims to propose a method and system for dynamic characteristic matching and machining path planning of CNC machine tools for efficient cutting. By introducing the dynamic performance parameters of CNC machine tools, an association mechanism with the machining path generation process is established. Based on the multiple machining schemes generated by CAM software, the machining stiffness and vibration characteristics are calculated in combination with the material properties of the parts, and the optimal machining scheme that matches the current machine tool performance is screened; and further according to the relationship between the machine tool acceleration and the part quality, the tool path sequence and speed profile are optimized, and at the same time, the tool path smoothness is compensated by the speed look-ahead model, so as to realize the dynamic coupling and coordinated matching of the machining path and the CNC machine tool capabilities, thereby improving the stability, accuracy and efficiency of the machining process and meeting the needs of efficient and flexible manufacturing in a heterogeneous equipment environment.

[0009] (2) Technical solution

[0010] In order to achieve the purpose of the invention and solve the technical problems, the present invention adopts the following technical solutions:

[0011] The first object of the present invention is to provide a method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting, which is used to match the CNC machining path with the dynamic performance parameters of the CNC machine tool to improve the stability, accuracy, and efficiency of the machining process. The method comprises the following steps:

[0012] S100. Generate multiple processing plans:

[0013] Based on the CAD 3D drawing of the part to be machined, the CAD 3D drawing is imported into the CAM software system. The geometric features of the part are extracted through feature recognition to determine the machined and non-machined surfaces of the part. Combined with the machining parameter requirements of the drawing, the CAM software generates multiple machining plans and corresponding process parameters for different machining surfaces of the part.

[0014] S200. Processing solution suitability screening:

[0015] Based on the generated multiple processing schemes for different processing surfaces, the processing stiffness and vibration parameters under each processing scheme are calculated in combination with the part material data. At the same time, the standard stiffness and vibration parameters of the current CNC machine tool are collected and compared with the corresponding processing stiffness and vibration parameters under different processing schemes, and the processing schemes that meet the characteristics of the current CNC machine tool are selected and retained;

[0016] S300. Tool Path Planning and Dynamic Compensation:

[0017] The retained machining plans for different machining surfaces are integrated, and the acceleration of the current CNC machine tool is calculated in combination with the part mass. The tool path combinations for different machining surfaces are generated to obtain the tool path plan. Combined with the electrical system response speed of the current CNC machine tool, the tool path smoothness in the tool path plan is compensated to obtain the final tool machining path.

[0018] The second object of the present invention is to provide a CNC machine tool dynamic characteristic matching and machining path planning system for efficient cutting, comprising at least:

[0019] A machining feature recognition unit is used to import the CAD 3D drawing of the part to be machined into the CAM software system, extract the geometric information of the part through the feature recognition module, and further determine and mark the machined and non-machined surfaces of the part;

[0020] A processing plan generation unit performs sub-plan modeling based on different processing surfaces and generates multiple processing plans with different process parameter configurations according to the recognition results and drawing parameter requirements;

[0021] A machining dynamic characteristic calculation unit calculates the dynamic stiffness parameters and vibration characteristic indicators under each machining scheme by setting a mechanical model and combining the material parameters of the parts involved in each machining scheme;

[0022] a machine tool performance database unit for storing standard performance parameters of the currently used CNC machine tools, including at least standard stiffness, standard vibration frequency, standard damping ratio, electrical system response speed, and acceleration-load characteristic relationship curve;

[0023] a processing plan adaptability determination unit, configured to compare each of the processing plan indicators output by the processing dynamic characteristics calculation unit with the standard performance parameters in the machine tool performance database, and select a processing plan that meets the dynamic performance matching conditions according to a preset determination logic;

[0024] A tool path planning and combination optimization unit is used to integrate all retained processing plans and optimize the processing sequence. It combines the weight changes of the parts under each processing surface and the relationship between the machine tool's acceleration and mass characteristics to generate a tool path combination plan corresponding to each processing surface and output preliminary path data.

[0025] A path dynamic compensation unit is used to dynamically adjust and smoothness compensate the preliminary path data based on the speed look-ahead model in combination with the response time constant of the machine tool electrical control system, so as to generate a final processing path that meets the dynamic response characteristics of the machine tool control system.

[0026] (3) Technical effects

[0027] Compared with the prior art, the method and system for dynamic characteristic matching and machining path planning of CNC machine tools for efficient cutting of the present invention have the following beneficial and significant technical effects:

[0028] 1. The present invention divides the machining surface of the machined part, generates multiple machining plans based on different machining surfaces, calculates the change in the part's damping ratio and stiffness in different machining plans, and determines the machining plan based on the stiffness and vibration parameters of the current CNC machine tool, retaining the machining plan that meets the characteristics of the actual CNC machine tool to achieve the best part machining effect;

[0029] 2. This invention optimizes the acceleration in the generated tool path based on the relationship between part quality and CNC machine acceleration and part quality, ensuring that the acceleration matches the CNC machine acceleration during machining of each machining surface. This can reduce vibration and chatter problems caused by excessive acceleration during machining, thereby improving machining accuracy and surface finish, and making the machining plan conform to the characteristics of current CNC machine tools.

[0030] 3. The present invention compensates for the smoothness of the tool path by combining the response speed of the current CNC machine tool electrical system, reduces the following error of the tool path, and enables the tool to move more accurately along the predetermined path, thereby improving the processing accuracy. Targeted compensation is performed according to the response characteristics of the electrical systems of different machine tools, making the tool path more in line with the capabilities of the CNC machine tool, thereby enhancing the functionality and practicality of the method. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in 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 paying any creative work.

[0032] Figure 1 This is a flow chart of a method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to an embodiment of the present invention.

[0033] Figure 2 This is a framework diagram of a dynamic characteristic matching and machining path planning system for CNC machine tools for efficient cutting according to an embodiment of the present invention.

[0034] Description of reference numerals:

[0035] Machining feature recognition unit 10, machining plan generation unit 20, machining dynamic characteristics calculation unit 30, machine tool performance database unit 40, machining plan adaptability judgment unit 50, tool path planning and combination optimization unit 60, path dynamic compensation unit 70, data processing and control unit 80, CNC machine tool control system 100. DETAILED DESCRIPTION

[0036] The present invention aims to provide a method and system for dynamic characteristic matching and machining path planning for CNC machine tools for efficient cutting, which is used to match the CNC machining path with the dynamic performance parameters of the CNC machine tool to improve the stability, accuracy, and efficiency of the machining process. To further illustrate various embodiments, the present invention provides accompanying drawings, which form part of the disclosure of the present invention and are primarily used to illustrate the embodiments and, in conjunction with the relevant description in the specification, to explain the operating principles of the embodiments. By referring to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention.

[0037] Example 1: Machine Tool Dynamic Characteristics Matching and Processing Path Planning Method

[0038] like Figure 1As shown, the embodiment of the present invention provides a method for matching the dynamic characteristics of machine tools and planning machining paths for efficient cutting, which aims to improve the degree of coordinated matching between the machining path and the dynamic performance of the machine tool during CNC machining, thereby effectively improving the stability, machining accuracy and overall efficiency of the machining process. The implementation of this method mainly includes the following steps:

[0039] S100. Generate multiple processing plans:

[0040] Based on the CAD three-dimensional drawing of the part to be processed, the CAD three-dimensional drawing is imported into the CAM software system, and the geometric features of the part (such as holes, grooves, bosses, surfaces, etc.) are extracted through feature recognition to determine the processing surface and non-processing surface of the part; then, combined with the processing parameter requirements of the drawing (such as dimensional tolerance, surface roughness, etc.), multiple processing schemes for different processing surfaces of the part and corresponding process parameters (such as cutting method, tool type, feed speed, cutting depth, cooling method, etc.) are generated through CAM software to form a structured processing plan set, which provides a data basis for subsequent dynamic matching and screening.

[0041] S200. Processing solution suitability screening:

[0042] For the various processing schemes for different processing surfaces generated by the CAM software system, combined with the part material data (such as elastic modulus, density) and processing volume changes, the processing stiffness and vibration parameters under each processing scheme are calculated. At the same time, the standard stiffness and vibration parameters of the current CNC machine tool (such as natural frequency and damping ratio, etc.) are collected and compared with the corresponding processing stiffness and vibration parameters under different processing schemes to determine whether each processing scheme meets the dynamic performance adaptation conditions of the current machine tool, and eliminate mismatched schemes. Only processing schemes that meet the characteristics of the current CNC machine tool are retained, thereby improving the dynamic adaptability and robustness of the processing path from the source.

[0043] S300. Tool Path Planning and Dynamic Compensation:

[0044] The machining plans for the different machining surfaces selected and retained in step S200 are integrated. The current CNC machine tool's acceleration is calculated based on the part quality of each machining surface during machining, and tool path combinations for the different machining surfaces are generated to obtain a tool path plan. The CNC machine tool's acceleration-load mapping relationship is also introduced. Combined with the current CNC machine tool's electrical system response speed, a velocity look-ahead compensation strategy and path smoothing technology are used to compensate for tool path smoothness in the tool path plan. This corrects for speed discontinuities, acceleration jumps, and dynamic lag between path segments, ultimately obtaining an optimal tool machining path that meets the machine tool's dynamic control performance, possesses high execution accuracy, and reduces vibration risk.

[0045] Through the above steps, this embodiment achieves a multi-dimensional match between part processing solutions and machine tool dynamic performance. It also integrates path planning and control response characteristic compensation mechanisms, laying the foundation for intelligent optimization of machining paths in efficient cutting scenarios. Subsequent examples will further refine the specific algorithm design, physical modeling methods, and implementation paths of the system functional modules for each of the above steps.

[0046] Example 2: Generation of multiple processing plans

[0047] Based on the overall method framework proposed in the above embodiment 1, this embodiment 2 further explains the process of generating multiple processing plans in step S100 in detail to facilitate a more comprehensive understanding of the technical solution of the present invention. Specifically, step S100 may include the following sub-steps when implemented:

[0048] S110. Import the CAD drawing of the part to be machined into the CAM software system. Using geometric analysis and topology recognition algorithms, identify and extract typical geometric features of the part, including at least holes, slots, bosses, chamfers, and surface contours, and construct a geometric model dataset of the part to be machined.

[0049] S120. Based on the extracted geometric structure feature information, the machined and non-machined surfaces of the part to be machined are identified and marked according to feature type, size distribution, and processing priority classification;

[0050] S130. Based on the machining parameter requirements of the CAD 3D drawing of the part to be machined, multiple machining plans and corresponding process parameter configurations are generated for each machining surface using the path template rules preset in the CAM software system. The plan parameters are then associated with the machining surface index in a one-to-one data structure.

[0051] It should be noted that the processing parameter requirements of CAD three-dimensional drawings include the basic geometric dimensions of different processing surfaces such as length, width, height, diameter, radius, dimensional tolerances, form and position tolerances, surface roughness, etc. of different processing surfaces. Processing solutions include turning, milling, drilling, boring, and grinding. Process parameters include cutting speed, feed rate, cutting depth, tool type, cooling method, etc. The number of processing solutions for the processing surface is generally set to 5, and can also be increased or decreased according to actual needs. By obtaining different processing solutions for multiple processing surfaces, it is convenient to screen the processing solutions in combination with the characteristics of CNC machine tools.

[0052] Example 3: Processing scheme suitability screening

[0053] To further refine step S200 in Example 1, this Example 3 elaborates on the process of screening the compatibility between the processing plan and the dynamic characteristics of the CNC machine tool based on the generation of multiple processing plans. Specifically, step S300 may include the following sub-steps when implemented:

[0054] S210. Combined with the various machining schemes and process parameters generated by the CAM software system for different machining surfaces, the machining stiffness and machining vibration parameters corresponding to each machining scheme for different machining surfaces are calculated based on the material properties of the part to be machined.

[0055] S220. Based on the standard stiffness and standard vibration parameters of the current CNC machine tool, various processing solutions for different processing surfaces are screened, and processing solutions that do not meet the dynamic matching conditions are eliminated, while those that match the characteristics of the current CNC machine tool are retained.

[0056] In a preferred embodiment of the present invention, step S210 includes the following sub-steps when implemented:

[0057] S211. Collect the material properties of the parts to be processed, including at least the elastic modulus of the parts E and part density r , the part quality is calculated based on the machining volume change, and the specific algorithm formula is:

[0058] ;

[0059] in, m is the mass of the part in the current state, is the dynamic volume of the part and satisfies ,in V 0. V c Represent the initial volume of the part and the cutting volume during the machining process respectively; then calculate the initial stiffness and vibration parameters of the part, the algorithm formula is:

[0060]

[0061] in, is the initial stiffness of the part, A is the cross-sectional area of ​​the part, that is, the area perpendicular to the length direction, L is the size of the part in the direction of force, l is the natural frequency of the part, g is the initial damping ratio of the part, c is the damping coefficient.

[0062] It should be noted that CAM software can be used to calculate and obtain the volume changes of parts in different processing steps, and combined with the subsequent cutting force time points, the dynamic volume of the current part at different cutting force time points can be obtained. The stiffness of the processed parts mainly depends on the elastic modulus of the material, which is the basic physical property of the material. The larger the elastic modulus, the higher the stiffness of the material. It is both the initial stiffness and the maximum stiffness of the current part.

[0063] S212. Extracting real-time process parameters corresponding to different machining plans for the same machining surface generated by the CAM software system, including cutting force coefficients , cutting depth , feed rate , tool cutting edge length ,in, I、I Respectively represent the part processing surface and processing plan number, i The value is 1 to n , n is the number of machining plans under the machining surface, and the real-time cutting force under different machining plans is calculated. The algorithm formula is:

[0064] ;

[0065] in, Representative processing surface I Next i Real-time cutting forces for various machining solutions;

[0066] pass Combined with the material properties of the parts, the real-time machining stiffness variation and real-time machining vibration parameters of different machining schemes on the same machining surface are calculated. The algorithm formula is:

[0067] ;

[0068] in, Machining surface of the part I The next i The real-time machining stiffness variation in the machining scheme, m represents the proportionality coefficient, E、A They represent the elastic modulus of the part and the cross-sectional area of ​​the processing process respectively.

[0069] It should be noted that m The representative proportional coefficient needs to be derived through finite element analysis. In the finite element method, the part is discretized into multiple units, and the deformation and stiffness of the part are analyzed through the relationship between the unit stiffness matrix and the overall stiffness matrix. According to the boundary conditions of the part, such as the fixed end, the free end, etc., and the connection relationship of the unit, the relationship between the stiffness change and the deformation under the action of the cutting force is derived, thereby obtaining the proportional coefficient. m , cross-sectional area ASpecific analysis is required based on different processing schemes. For example, the cross-sectional area of ​​shaft parts usually refers to the circular cross-sectional area of ​​the shaft. The cutting force in the milling plane is decomposed into components perpendicular to the plane and parallel to the plane. The cross-sectional area is the area related to the thickness of the part in the direction perpendicular to the main action direction of the cutting force. When drilling holes, the cross-sectional area usually refers to the circular cross-sectional area of ​​the drilled hole. When defining and analyzing the part processing surface in the CAM environment, the measurement tools of the CAM software are used to obtain information related to the cross-sectional area.

[0070] According to the real-time machining stiffness change Calculate the real-time damping ratio of parts during processing , and its algorithm formula is:

[0071] ;

[0072] in, is the part quality in the current state, Represents the real-time value of the part stiffness in the current state, c For the damping coefficient, simulate the current processing plan in the CAM software system to obtain the real-time damping ratio The change curve of the maximum damping ratio is obtained And it is used as a dynamic matching evaluation index. It should be noted that the damping coefficient c It is usually related to the material and processing environment. In the CAM software, the damping characteristics of the material will be pre-set according to the properties of the current part. The larger the damping ratio of the part, the greater the damping ratio required for the CNC machine tool during the part processing.

[0073] In a preferred embodiment of the present invention, step S220 includes the following sub-steps when implemented:

[0074] S221. For current CNC machine tools, static loading tests are performed on key stress-bearing parts. A constant load is applied and deformation is measured. The standard stiffness of the machine tool is calculated based on the force-displacement relationship. Apply initial disturbance to the machine tool through the exciter, make it vibrate freely and record the vibration signal, and obtain the standard vibration frequency of the machine tool through spectrum analysis l 0; further collect the vibration attenuation curve of the free attenuation process, analyze the logarithmic attenuation rate of the attenuation curve, and obtain the standard damping ratio of the machine tool g 0;

[0075] S222. Standard stiffness based on CNC machine tools , standard vibration frequency l 0 and standard damping ratio g 0, judge the processing plan of each processing surface one by one: if the processing plan meets the requirements of 、 l < l 0. g < g 0 and < g 0 If all four conditions are met, it means that the processing plan meets the characteristics of the current CNC machine tool, and the processing plan will be retained. If the processing plan cannot meet all four conditions at the same time, it means that it does not meet the characteristics of the current CNC machine tool, and the processing plan will be deleted.

[0076] Further preferably, in step S222, when none of the processing solutions for a certain processing surface meets the characteristics of the current CNC machine tool, a secondary determination is performed on the processing solutions for the processing surface:

[0077] If some processing solutions meet 、 l < l 0. g < g 0. When , step S100 is repeated to regenerate the machining plan for the current machining surface and accumulate 1 machining threshold. When the machining threshold is greater than 3, it is determined that the part cannot be machined under the current CNC machine tool equipment conditions, and the machining path planning process for the part is terminated;

[0078] If there is a processing plan under the processing surface or l ≥ l 0 or g ≥ g When the value is 0, it is directly determined that the part cannot be processed on the current CNC machine tool, and the processing path planning process for the part is terminated.

[0079] It should be noted that by repeating step S1 for parts whose basic values ​​meet the characteristics of CNC machine tools and whose processing values ​​do not meet the characteristics of CNC machine tools, regenerating the processing plan and re-evaluating the feasibility of the processing plan, it helps to reduce the occurrence of misjudgments.

[0080] Example 4: Tool path planning and dynamic compensation

[0081] After completing the screening of machining plans and obtaining the adapted plan, this fourth embodiment further refines step S300 described in the first embodiment, systematically describing the combined planning of tool paths and their deep integration with characteristics such as machine tool acceleration and electrical system response. Specifically, step S300 may include the following sub-steps during implementation:

[0082] S310. Based on the selected machining plans for each machining surface, combined with the part quality after machining each machining surface in the CAM software system, and based on the nonlinear mapping relationship model between CNC machine tool acceleration and part quality, the acceleration of each machining surface is obtained. Tool path combinations for different machining surfaces are generated based on the machining sequence and adjacent path logic to obtain a tool path plan. It should be noted that the relationship between CNC machine tool acceleration and machined part quality can be modeled by selecting standard parts of different weights, installing them on the machine tool, setting the machine tool acceleration parameters, recording the actual measured acceleration values, and using a fitting tool to fit the current machine tool acceleration to part quality.

[0083] S320. Combine the dynamic response capabilities of the electrical control system of current CNC machine tools and extract the response time constant of the control system. t , and introduces a speed look-ahead algorithm to compensate for the tool path smoothness in the tool path solution, where at any time point t The machine tool should reach the speed value v ( t ) is calculated based on the following formula:

[0084] ;

[0085] in, v α is the nominal speed, that is, the stable speed value expected to be achieved, t 0 is the starting time; based on v ( t ) The speed curve compensates for the smoothness of the tool path in the CAM software system, optimizes the tool acceleration and deceleration process, eliminates the speed discontinuity defect between path segments, and obtains the final tool processing path. It should be noted that the time constant t Determines how fast the speed increases. If t If the value is large, the speed will increase slowly, otherwise it will increase quickly. t The value of usually needs to be determined according to the specific response speed of the CNC machine tool electrical system to ensure that neither mechanical shock is caused by excessive acceleration nor production efficiency is affected by excessively slow acceleration.

[0086] In a preferred embodiment of the present invention, step S310 includes the following sub-steps when implemented:

[0087] S311. Use CAM software to generate preliminary tool paths based on the machining plans for different machining surfaces, simulate the machining process for each machining surface, and obtain the quality of the parts after machining each machining surface. Q I ,in I The index number of the machining surface;

[0088] S312. Substitute the part mass into the established acceleration and part mass relationship model. Q I , obtain the target acceleration of each processing surface a I ; Based on the target acceleration of each machining surface a I and non-cutting path distance, using the shortest path algorithm to optimize the tool path sequence, minimize the idle travel time and the total length of the path, and at the same time according to the acceleration of each processing surface a I , adjust the velocity profile and acceleration profile of the tool path to ensure that the acceleration of each processing surface matches the calculated value. It should be noted that the entire tool path is divided into several small segments, each segment corresponds to a processing surface, and each small segment is adjusted according to the target acceleration. a I Set the part rotation time to achieve precise control of the machining process.

[0089] In a preferred embodiment of the present invention, step S320 includes the following sub-steps when implemented:

[0090] S321. Obtain the basic response time constant of the current CNC machine control system t , and dynamically adjust the compensation model based on the complexity of the actual machining task, the speed variation between path segments and / or the tool switching frequency factors. t value, so that the speed look-ahead compensation strategy has the ability to adjust parameters adaptively under different processing conditions. t Value adjustment rules include:

[0091] When there are continuous high-speed sections in the machining path and the speed variation between paths is small, reduce t value to speed up system response and reduce hysteresis error;

[0092] When the speed between paths changes suddenly or the direction switches frequently or the tool acceleration and deceleration gradient is large, increase t The value is used to improve the transition smoothness between path segments and suppress system oscillation;

[0093] When the part has a complex structure, many corners or a sharp change in contour, the vibration and control accuracy requirements should be comprehensively considered. t The value is incrementally corrected to optimize the overall smoothness and processing stability;

[0094] S322. After dynamic parameter adjustment tThe value is updated to the speed look-ahead compensation model in real time, and the target speed v(t) at any moment is recalculated according to the current time t of path execution and the start time t0 of the path segment to adjust the speed profile in the current tool motion control instruction, realize dynamic adaptive smooth compensation of the tool path, and improve the control stability and processing consistency of the system under different working conditions.

[0095] Further preferably, step S320 may further include the following sub-steps during implementation:

[0096] S323. After the dynamically compensated tool path is generated, the CAM software system's built-in path simulation module is called to perform virtual execution simulation and trajectory error analysis on the machining path. The simulation module predicts and calculates the entire path process based on the CNC machine tool's dynamic model, electrical system response model, and tool feed model.

[0097] S324. Real-time monitoring of path execution errors, including velocity lag, acceleration jump, path deviation during direction change, and vibration-induced risk indicators. When the error value of a processing segment exceeds the preset deviation threshold, it is automatically fed back to the velocity look-ahead compensation model and triggers the response time constant. t , tool speed v α or acceleration boundary a limit Fine-tuning forms an error-driven path dynamic iterative correction process;

[0098] S325. Regenerate the tool path based on the updated path compensation parameters and perform simulation verification again. If the error values ​​of all processing segments are within the tolerance band, the corrected path is output as the final processing path, completing the tool path optimization process based on error closed-loop control.

[0099] Example 5: Machine tool dynamic characteristics matching and processing path planning system

[0100] On the basis of the above-mentioned embodiments 1 to 4, Figure 2 As shown, this embodiment 5 further provides a machine tool dynamic characteristic matching and machining path planning system for efficient cutting corresponding to the above method, which mainly includes the following unit modules:

[0101] The machining feature recognition unit 10 is used to import the CAD three-dimensional drawing of the part to be machined into the CAM software system, and extract the geometric information of the part through the feature recognition module, and further determine and mark the machined surface and non-machined surface of the part.

[0102] The processing plan generating unit 20 performs sub-plan modeling based on different processing surfaces, and generates multiple processing plans with different process parameter configurations according to the recognition results and drawing parameter requirements.

[0103] The machining dynamic characteristic calculation unit 30 calculates the dynamic stiffness parameters and vibration characteristic indexes under each machining scheme by setting a mechanical model and combining the material parameters of the parts involved in each machining scheme.

[0104] The machine tool performance database unit 40 is used to store standard performance parameters of the currently used CNC machine tool, including at least standard stiffness, standard vibration frequency, standard damping ratio, electrical system response speed and acceleration-load characteristic relationship curve.

[0105] The processing scheme adaptability determination unit 50 is used to compare each indicator of the processing scheme output by the processing dynamic characteristic calculation unit with the standard performance parameters in the machine tool performance database, and select the processing scheme that meets the dynamic performance matching conditions according to the preset determination logic.

[0106] The tool path planning and combination optimization unit 60 is used to integrate all the retained processing plans and optimize the processing sequence. It combines the weight change of the part under each processing surface and the relationship between the acceleration and mass characteristics of the machine tool to generate a tool path combination plan corresponding to each processing surface and output preliminary path data.

[0107] The path dynamic compensation unit 70 is used to dynamically adjust and smoothness compensate the preliminary path data based on the speed look-ahead model in combination with the response time constant of the machine tool electrical control system, and generate a final processing path that meets the dynamic response characteristics of the machine tool control system.

[0108] Furthermore, the machine tool dynamic characteristic matching and machining path planning system for efficient cutting according to an embodiment of the present invention further includes a data processing and control unit 80 for coordinating data transmission and processing flows between various functional units, including a data storage module, a logic control module, and a result output module, wherein:

[0109] The data storage module is used to store part material data, machine tool characteristic parameters, processing plan data and path planning results; the logic control module is used to control each functional unit to perform corresponding operations according to the predetermined process, ensuring the orderly generation of multiple processing plans, adaptability screening, path planning and compensation; the result output module is used to output the final tool processing path to the CNC machine tool control system, realizing the automatic implementation of machine tool dynamic characteristic matching and processing path planning for efficient cutting.

[0110] In summary, the present invention divides the machining surface of the machined part, generates multiple machining plans based on different machining surfaces, calculates the change in the part damping ratio and stiffness in different machining plans, and determines the machining plan based on the stiffness and vibration parameters of the current CNC machine tool. The machining plan is retained to achieve the best part machining effect. In addition, the present invention optimizes the acceleration in the generated tool path based on the relationship between the CNC machine tool acceleration and the part mass, ensuring that the acceleration meets the CNC machine tool acceleration when machining each machining surface. This can reduce vibration and chatter problems caused by excessive acceleration during machining, thereby improving machining accuracy and surface finish, making the machining plan consistent with the characteristics of the current CNC machine tool. In combination with the dynamic performance of the CNC machine tool, including the machine tool stiffness, vibration, machine tool acceleration, and the response speed of the electrical system, the tool path planning and process parameters in the CAM programming process are matched, so as to achieve tailored CNC programming for different machine tools.

[0111] The above embodiments fully and effectively achieve the objectives of the present invention. Those skilled in the art will appreciate that the present invention includes, but is not limited to, the contents described in the accompanying drawings and the above specific embodiments. Although the present invention has been described with reference to the embodiments currently considered to be the most practical and preferred, it should be understood that the present invention is not limited to the disclosed embodiments, and any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A method for dynamic characteristic matching and machining path planning of CNC machine tools for efficient cutting, characterized in that: At least the following steps are included: S100. Based on a 3D CAD drawing of the part to be machined, the drawing is imported into the CAM software system. Feature recognition is used to extract the part's geometric features and determine the machined and non-machined surfaces. Based on the machining parameters specified in the drawing, the CAM software generates multiple machining plans and corresponding process parameters for different machined surfaces of the part. S200. Calculate the machining stiffness and vibration parameters for each of the generated machining plans for different machining surfaces, combining the part material data. Simultaneously, collect the standard stiffness and vibration parameters of the current CNC machine tool and compare them with the corresponding machining stiffness and vibration parameters for the different machining plans. Select and retain the machining plans that meet the characteristics of the current CNC machine tool. S300. Integrate the retained machining plans for different machining surfaces. Calculate the current CNC machine tool acceleration based on part mass, generate tool path combinations for different machining surfaces, and obtain a tool path plan. Compensate for tool path smoothness in the tool path plan based on the current CNC machine tool's electrical system response speed to obtain the final tool path. This step includes: S310. Based on the selected machining plans for each machining surface, combined with the part quality after machining each machining surface in the CAM software system, and using a nonlinear mapping relationship model between CNC machine tool acceleration and part quality, the acceleration of each machining surface is obtained. Tool path combinations for different machining surfaces are generated based on the machining sequence and adjacent path logic, resulting in a tool path plan, including: S311. Use CAM software to generate preliminary tool paths based on the machining plans for different machining surfaces, simulate the machining process for each machining surface, and obtain the quality of the parts after machining each machining surface. Q I ,in I Number the machining surface; S312. Substitute the part mass into the established acceleration and part mass relationship model. Q I , obtain the target acceleration of each processing surface a I ; Based on the target acceleration of each machining surface a I and non-cutting path distance, using the shortest path algorithm to optimize the tool path sequence, minimize the idle travel time and the total length of the path, and at the same time according to the acceleration of each processing surface a I , adjust the velocity profile and acceleration profile of the tool path to ensure that the acceleration of each machining surface matches the calculated value; S320. Combine the dynamic response capabilities of the electrical control system of current CNC machine tools and extract the response time constant of the control system. τ , and introduces a speed look-ahead algorithm to compensate for the tool path smoothness in the tool path solution, where at any time point t The machine tool should reach the speed value v ( t ) is calculated based on the following formula: in, is the nominal speed, that is, the stable speed value expected to be achieved, t 0 is the starting time; based on v ( t ) The speed curve compensates for the smoothness of the tool path in the CAM software system, optimizes the tool acceleration and deceleration process, eliminates the speed discontinuity defect between path segments, and obtains the final tool processing path.

2. The method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to claim 1, characterized in that: Step S100 includes the following sub-steps during implementation: S110. Import the CAD drawing of the part to be machined into the CAM software system. Using geometric analysis and topology recognition algorithms, identify and extract typical geometric features of the part, including at least holes, slots, bosses, chamfers, and surface contours, and construct a geometric model dataset of the part to be machined. S120. Based on the extracted geometric structure feature information, the machined and non-machined surfaces of the part to be machined are identified and marked according to feature type, size distribution, and processing priority classification; S130. Based on the machining parameter requirements of the CAD 3D drawing of the part to be machined, multiple machining plans and corresponding process parameter configurations are generated for each machining surface using the path template rules preset in the CAM software system. The plan parameters are then associated with the machining surface index in a one-to-one data structure.

3. The method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to claim 1, characterized in that: Step S200 includes the following sub-steps when implemented: S210. Combined with the various machining schemes and process parameters generated by the CAM software system for different machining surfaces, the machining stiffness and machining vibration parameters corresponding to each machining scheme for different machining surfaces are calculated based on the material properties of the part to be machined. S220. Based on the standard stiffness and standard vibration parameters of the current CNC machine tool, various processing solutions for different processing surfaces are screened, and processing solutions that do not meet the dynamic matching conditions are eliminated, while those that match the characteristics of the current CNC machine tool are retained.

4. The method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to claim 3, characterized in that: Step S210 includes the following sub-steps during implementation: S211. Collect the material properties of the parts to be processed, including at least the elastic modulus of the parts E and part density , the part quality is calculated based on the machining volume change, and the algorithm formula is: ,in, m is the mass of the part in the current state, is the dynamic volume of the part and satisfies ,in V 0. V c Represent the initial volume of the part and the cutting volume during the machining process respectively; then calculate the initial stiffness and vibration parameters of the part, the algorithm formula is: in, is the initial stiffness of the part, A is the cross-sectional area of ​​the part, that is, the area perpendicular to the length direction, L is the size of the part in the direction of force, λ is the natural frequency of the part, is the initial damping ratio of the part, c is the damping coefficient; S212. Extract real-time process parameters corresponding to different machining schemes on the same machining surface, including cutting force coefficients , cutting depth , feed rate , tool cutting edge length , where they represent the part processing surface and the processing plan number, with values ​​ranging from 1 to n , n is the number of machining plans under the machining surface, and the real-time cutting force under different machining plans is calculated. The algorithm formula is: ,in Representative processing surface I Next i Real-time cutting forces for various machining solutions; pass Combined with the material properties of the parts, the real-time machining stiffness change and real-time machining vibration parameters of different machining schemes under the same machining surface are calculated. The algorithm formula is: ,in Machining surface of the part I The next i The real-time machining stiffness variation in the machining scheme, μ represents the proportional coefficient, which represents the elastic modulus of the part and the cross-sectional area of ​​the processing process; According to the real-time machining stiffness change Calculate the real-time damping ratio of parts during processing , and its algorithm formula is ,in, is the part quality in the current state, Represents the real-time value of the part stiffness in the current state, c For the damping coefficient, simulate the current processing plan in the CAM software system to obtain the real-time damping ratio The change curve of the maximum damping ratio is obtained And used as a dynamic matching evaluation indicator.

5. The method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to claim 4, characterized in that: Step S220 includes the following sub-steps during implementation: S221. For current CNC machine tools, static loading tests are performed on key stress-bearing parts. A constant load is applied and deformation is measured. The standard stiffness of the machine tool is calculated based on the force-displacement relationship. Apply initial disturbance to the machine tool through the exciter, make it vibrate freely and record the vibration signal, and obtain the standard vibration frequency of the machine tool through spectrum analysis ; Further collect the vibration attenuation curve of the free attenuation process, analyze the logarithmic attenuation rate of the attenuation curve, and obtain the standard damping ratio of the machine tool ; S222. Standard stiffness based on CNC machine tools , standard vibration frequency and standard damping ratio , judge the processing plans for each processing surface one by one: if the processing plan satisfies 、 、 and If all four conditions are met, it means that the processing plan meets the characteristics of the current CNC machine tool, and the processing plan will be retained. If the processing plan cannot meet all four conditions at the same time, it means that it does not meet the characteristics of the current CNC machine tool, and the processing plan will be deleted.

6. The method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to claim 5, characterized in that: In step S222, when none of the machining plans for a certain machining surface meets the characteristics of the current CNC machine tool, a secondary determination is performed on the machining plans for the machining surface: If some processing solutions meet When , step S100 is repeated to regenerate the machining plan for the current machining surface and accumulate 1 machining threshold. When the machining threshold is greater than 3, it is determined that the part cannot be machined under the current CNC machine tool equipment conditions, and the machining path planning process for the part is terminated; If there is a processing plan under the processing surface or or , it is directly determined that the part cannot be processed on the current CNC machine tool, and the processing path planning process for the part is terminated.

7. The method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to claim 1, characterized in that: Step S320 includes the following sub-steps during implementation: S321. Obtain the basic response time constant of the current CNC machine control system , and dynamically adjust the compensation model based on the complexity of the actual machining task, the speed variation between path segments and / or the tool switching frequency factors. value, so that the speed look-ahead compensation strategy has the ability to adjust parameters adaptively under different processing conditions. Value adjustment rules include: When there are continuous high-speed sections in the machining path and the speed variation between paths is small, reduce value to speed up system response and reduce hysteresis error; When the speed between paths changes suddenly or the direction switches frequently or the tool acceleration and deceleration gradient is large, increase The value is used to improve the transition smoothness between path segments and suppress system oscillation; When the part has a complex structure, many corners or a sharp change in contour, the vibration and control accuracy requirements should be comprehensively considered. The value is incrementally corrected to optimize the overall smoothness and processing stability; S322. After dynamic parameter adjustment The value is updated in real time to the speed look-ahead compensation model and is calculated based on the current time of the path execution. t and the route segment start time t 0, recalculate the target speed v(t) at any time to adjust the speed profile in the current tool motion control instruction, realize dynamic adaptive smooth compensation of the tool path, and improve the control stability and processing consistency of the system under different working conditions.

8. The method for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to claim 7, characterized in that: Step S320 further includes the following sub-steps during implementation: S323. After the dynamically compensated tool path is generated, the CAM software system's built-in path simulation module is called to perform virtual execution simulation and trajectory error analysis on the machining path. The simulation module predicts and calculates the entire path process based on the CNC machine tool's dynamic model, electrical system response model, and tool feed model. S324. Real-time monitoring of path execution errors, including velocity lag, acceleration jump, path deviation during direction change, and vibration-induced risk indicators. When the error value of a processing segment exceeds the preset deviation threshold, it is automatically fed back to the velocity look-ahead compensation model and triggers the response time constant. , tool speed or acceleration boundary a limit Fine-tuning forms an error-driven path dynamic iterative correction process; S325. Regenerate the tool path based on the updated path compensation parameters and perform simulation verification again. If the error values ​​of all processing segments are within the tolerance band, the corrected path is output as the final processing path, completing the tool path optimization process based on error closed-loop control.

9. A dynamic characteristic matching and machining path planning system for CNC machine tools for efficient cutting, characterized in that: At least: A machining feature recognition unit is used to import the CAD 3D drawing of the part to be machined into the CAM software system, extract the geometric information of the part through the feature recognition module, and further determine and mark the machined and non-machined surfaces of the part; A processing plan generation unit performs sub-plan modeling based on different processing surfaces and generates multiple processing plans with different process parameter configurations according to the recognition results and drawing parameter requirements; A machining dynamic characteristic calculation unit calculates the dynamic stiffness parameters and vibration characteristic indicators under each machining scheme by setting a mechanical model and combining the material parameters of the parts involved in each machining scheme; a machine tool performance database unit for storing standard performance parameters of the currently used CNC machine tools, including at least standard stiffness, standard vibration frequency, standard damping ratio, electrical system response speed, and acceleration-load characteristic relationship curve; a processing plan adaptability determination unit, configured to compare each of the processing plan indicators output by the processing dynamic characteristics calculation unit with the standard performance parameters in the machine tool performance database, and select a processing plan that meets the dynamic performance matching conditions according to a preset determination logic; A tool path planning and combination optimization unit is used to integrate all the retained processing solutions and optimize the processing sequence. It combines the weight change of the part under each processing surface and the relationship between the machine tool acceleration and mass characteristics to generate the tool path combination solution corresponding to each processing surface and output the preliminary path data, specifically: Based on the machining plans for each machining surface that has been screened and retained, combined with the quality of the part after machining each machining surface in the CAM software system, and based on the nonlinear mapping relationship model between CNC machine acceleration and part quality, the acceleration of each machining surface is obtained respectively. Then, according to the machining sequence and adjacent path logic, tool path combinations for different machining surfaces are generated to obtain the tool path combination plan, including: Use CAM software system to generate preliminary tool paths based on the processing scheme of different processing surfaces, simulate the processing process of each processing surface, and obtain the quality of parts after processing each processing surface. Q I ,in I Number the machining surface; substitute the part mass according to the established relationship model between acceleration and part mass Q I , obtain the target acceleration of each processing surface a I ; Based on the target acceleration of each machining surface a I and non-cutting path distance, using the shortest path algorithm to optimize the tool path sequence, minimize the idle travel time and the total length of the path, and at the same time according to the acceleration of each processing surface a I , adjust the velocity profile and acceleration profile of the tool path to ensure that the acceleration of each machining surface matches the calculated value; A path dynamic compensation unit is used to dynamically adjust and smooth the preliminary path data based on the speed look-ahead model in combination with the response time constant of the machine tool electrical control system to generate a final machining path that meets the dynamic response characteristics of the machine tool control system. Specifically: Combined with the dynamic response capability of the electrical control system of the current CNC machine tool, the response time constant of the control system is extracted , and introduces a speed look-ahead algorithm to compensate for the tool path smoothness in the tool path solution, where at any time point t The machine tool should reach the speed value v ( t ) is calculated based on the following formula: in, is the nominal speed, that is, the stable speed value expected to be achieved, t 0 is the starting time; based on v ( t ) The speed curve compensates for the smoothness of the tool path in the CAM software system, optimizes the tool acceleration and deceleration process, eliminates the speed discontinuity defect between path segments, and obtains the final tool processing path.

10. The system for dynamic characteristic matching and machining path planning of a CNC machine tool for efficient cutting according to claim 9, characterized in that: It also includes a data processing and control unit for coordinating data transmission and processing flows between the functional units, including at least: A data storage module for storing part material data, machine tool characteristic parameters, processing plan data and path planning results; A logic control module is used to control each functional unit to perform corresponding operations according to the predetermined process, ensuring the orderly generation of multiple processing plans, adaptability screening, path planning and compensation; A result output module is used to output the final tool processing path to the CNC machine tool control system, realizing the automatic implementation of machine tool dynamic characteristic matching and processing path planning for efficient cutting.

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