Gantry numerical control milling machine high-precision curved surface machining method based on multi-axis linkage compensation

Abstract

The invention provides a gantry numerical control milling machine high-precision curved surface machining method based on multi-axis linkage compensation, and belongs to the technical field of numerical control machining, and the gantry numerical control milling machine high-precision curved surface machining method comprises the steps of S1, constructing a gantry numerical control milling machine multi-axis error model, the method comprises the following steps: measuring positioning errors, reverse clearance errors and perpendicularity errors of all axes of a gantry numerical control milling machine and synchronous errors during multi-axis linkage through measuring equipment such as a laser interferometer and a ball bar, and establishing a comprehensive error model comprising geometric errors, thermal deformation errors and multi-axis linkage errors of a machine tool; according to high-precision curved surface machining of the gantry numerical control milling machine, the machining precision and efficiency are remarkably improved through multi-dimensional technical innovation. In the aspect of error processing, a comprehensive error model is constructed, various errors such as geometry, thermal deformation and multi-axis linkage are accurately covered, and a solid data foundation is provided for compensation; in the machining process, the error compensation amount is dynamically adjusted by combining curved surface gridding and layered milling with real-time feedback.

Description

Technical Field

[0001] The present invention relates to the technical field of numerical control machining, and in particular to a high-precision curved surface machining method of a gantry numerical control milling machine based on multi-axis linkage compensation. Background Art

[0002] In modern manufacturing, gantry CNC milling machines are widely used in the processing of complex curved parts. With the continuous improvement of the requirements for part precision and surface quality in industries such as aerospace and automotive molds, higher challenges have been posed to the processing accuracy of gantry CNC milling machines. In the process of processing curved surfaces with gantry CNC milling machines, due to the influence of factors such as the positioning error of each axis of the machine tool, backlash error, thermal deformation error, and synchronization error during multi-axis linkage, there is a large deviation between the actual processed surface and the design model, which makes it difficult to meet the needs of high-precision processing. Although there are some error compensation methods in the prior art, most of them are aimed at compensating for single-axis errors, and the comprehensive error compensation effect during multi-axis linkage is not good, and high-precision curved surface processing cannot be achieved. Therefore, there is an urgent need for a method that can effectively compensate for multi-axis linkage errors and realize high-precision curved surface processing with gantry CNC milling machines.

[0003] Therefore, a high-precision surface machining method of gantry CNC milling machine based on multi-axis linkage compensation is proposed. Summary of the Invention

[0004] The present invention aims to solve the problems raised in the background technology and provides a high-precision surface processing method for a gantry CNC milling machine based on multi-axis linkage compensation. By comprehensively compensating for the various errors generated by the multi-axis linkage of the gantry CNC milling machine, the surface processing accuracy and surface quality are improved, thereby meeting the needs of modern manufacturing industry for high-precision processing.

[0005] The specific technical solutions are as follows:

[0006] A high-precision surface machining method for a gantry CNC milling machine based on multi-axis linkage compensation comprises the following steps:

[0007] S1: Construct a multi-axis error model for a gantry CNC milling machine. Using laser interferometers, ballbars, and other measuring equipment, the positioning error, backlash error, perpendicularity error, and synchronization error of each axis of the gantry CNC milling machine are measured. This creates a comprehensive error model that includes machine tool geometry error, thermal deformation error, and multi-axis linkage error.

[0008] S2: Meshing the surface to be processed, dividing the surface to be processed into multiple small grid units according to the processing accuracy requirements, and determining the vertex coordinates of each grid unit;

[0009] S3: Calculating the error compensation amount of each vertex during multi-axis linkage machining based on the comprehensive error model and the vertex coordinates of each grid unit, wherein the error compensation amount includes the displacement compensation amount and the rotation compensation amount along each axis direction;

[0010] S4: Convert the calculated error compensation amount into motion compensation instructions for each axis of the machine tool, and perform real-time correction on the motion trajectory of each axis of the machine tool;

[0011] S5: The machined surface is machined using a layered milling method. During each layer of machining, the actual position information and machining status information of each axis of the machine tool are collected in real time. The actual position information is compared with the corrected theoretical position information through a feedback control system. The error compensation amount is dynamically adjusted based on the comparison result to further improve the machining accuracy.

[0012] S6: Repeat step S5 until the entire surface is processed.

[0013] In the above-mentioned high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation, in step S1, the specific process of establishing the comprehensive error model is as follows:

[0014] First, the positioning error and backlash error of each axis at different positions are measured by laser interferometer, and the positioning error model and backlash error model of each axis are established;

[0015] Then, the ballbar is used to measure the contour error of multi-axis linkage, and the multi-axis linkage error model is established based on the geometric structure parameters of the machine tool.

[0016] Finally, by installing temperature sensors at key locations of the machine tool to monitor the temperature changes of the machine tool in real time, a thermal deformation error model is established. The above error models are then integrated to obtain a comprehensive error model that includes machine tool geometric error, thermal deformation error, and multi-axis linkage error.

[0017] In the above-mentioned high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation, in step S3, the method for calculating the error compensation amount of each vertex during multi-axis linkage machining is:

[0018] According to the comprehensive error model, the least squares method is used to fit the error of each vertex to obtain an error compensation function, and the displacement compensation and rotation compensation of each vertex along each axis direction during multi-axis linkage machining are calculated using the error compensation function.

[0019] In the above-mentioned high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation, in step S4, the method of converting the error compensation amount into the motion compensation instructions of each axis of the machine tool is:

[0020] According to the kinematic principle of the machine tool, the calculated error compensation amount is converted into the pulse equivalent of each axis of the machine tool, and the corresponding motion compensation instruction is generated. The motion compensation instruction is sent to the servo drive device of each axis of the machine tool through the CNC system to realize real-time correction of the motion trajectory of each axis of the machine tool.

[0021] In the above-mentioned high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation, in step S5, the method for real-time acquisition of the actual position information and machining status information of each axis of the machine tool is:

[0022] The actual position information of each axis is collected in real time by the grating ruler installed on each axis of the machine tool, and the cutting force, vibration and other processing status information during the processing are collected by force sensors, vibration sensors, etc.

[0023] In the above-mentioned high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation, in step S5, the actual position information is compared with the corrected theoretical position information through the feedback control system, and the method for dynamically adjusting the error compensation amount according to the comparison result is as follows:

[0024] The collected actual position information is compared with the corrected theoretical position information to calculate the position deviation. According to the position deviation and the preset control algorithm, the error compensation amount is dynamically adjusted to make the actual motion trajectory of each axis of the machine tool closer to the corrected theoretical motion trajectory.

[0025] The above-mentioned high-precision surface processing method of the gantry CNC milling machine based on multi-axis linkage compensation also includes: preheating the gantry CNC milling machine before processing to allow the machine tool to reach a thermal equilibrium state to reduce the impact of thermal deformation errors on processing accuracy.

[0026] The above-mentioned high-precision surface processing method of the gantry CNC milling machine based on multi-axis linkage compensation also includes: during the processing process, according to the characteristics of the processing material and the processing requirements, reasonably selecting tool parameters and cutting parameters to improve processing efficiency and surface quality.

[0027] The present invention further provides a high-precision curved surface machining system for a gantry CNC milling machine based on multi-axis linkage compensation, which is used to implement the above-mentioned high-precision curved surface machining method for a gantry CNC milling machine based on multi-axis linkage compensation, comprising:

[0028] Error measurement module, used to measure the positioning error, backlash error, verticality error of each axis of the gantry CNC milling machine, and synchronization error during multi-axis linkage;

[0029] An error modeling module is used to establish a comprehensive error model including machine tool geometric error, thermal deformation error and multi-axis linkage error based on the measurement results of the error measurement module;

[0030] a data processing module for performing gridding processing on the machined surface, calculating the error compensation amount of each grid unit vertex according to the comprehensive error model, and converting the error compensation amount into motion compensation instructions for each axis of the machine tool;

[0031] The processing control module is used to control the movement of each axis of the machine tool according to the motion compensation instruction, process the processing surface by layered milling, and dynamically adjust the error compensation amount through the feedback control system.

[0032] In the above-mentioned high-precision surface processing system of the gantry CNC milling machine based on multi-axis linkage compensation, the error measurement module includes a laser interferometer, a ballbar, a temperature sensor, a grating scale, a force sensor and a vibration sensor.

[0033] The present invention has the following beneficial effects:

[0034] 1. The present invention constructs a multi-axis error model of a gantry CNC milling machine to comprehensively measure and model various errors such as the positioning error of each axis, backlash error, perpendicularity error, and synchronization error during multi-axis linkage. It can comprehensively and accurately reflect the error status of the machine tool and provide a reliable basis for subsequent error compensation.

[0035] 2. The machining surface is meshed and combined with the multi-axis error model to calculate the error compensation amount of each grid unit vertex, and then convert it into motion compensation instructions for each axis of the machine tool. This realizes real-time correction of the motion trajectory of each axis of the machine tool, effectively compensates for multi-axis linkage errors, and improves the surface machining accuracy.

[0036] 3. During the machining process, by real-time acquisition of the actual position information and machining status information of each axis of the machine tool and using the feedback control system to dynamically adjust the error compensation amount, errors that occur during the machining process can be corrected in a timely manner, further improving machining accuracy and surface quality.

[0037] 4. The present invention also takes into account the influence of factors such as machine tool preheating, tool parameters and cutting parameter selection on processing accuracy. Through reasonable process arrangement, it can reduce thermal deformation error, improve processing efficiency and surface quality, and has strong practicality and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flow chart of a high-precision surface machining method for a gantry CNC milling machine based on multi-axis linkage compensation provided by an embodiment of the present invention;

[0039] Figure 2 This is a pie chart showing the proportion of machine tool errors;

[0040] Figure 3 This is a comparison chart between the actual trajectory and theoretical trajectory of each axis of the machine tool;

[0041] Figure 4 It is the dynamic adjustment diagram of the error compensation amount of each axis of the machine tool;

[0042] Figure 5 This is the working principle flow chart of the multi-axis linkage error compensation equation. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0044] Among them, the drawings are only used for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting this patent; in order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0045] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "inside", "outside" and the like indicate an orientation or position relationship based on the orientation or position relationship shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0046] In the description of the present invention, unless otherwise expressly specified or limited, when the term "connection" or the like appears to indicate a connection relationship between components, such term should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be internal communication between two components or an interaction between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood in specific circumstances.

[0047] Example

[0048] First of all, it is worth mentioning that Figure 1 The process of high-precision surface machining method of gantry CNC milling machine based on multi-axis linkage compensation is demonstrated; Figure 2 The pie chart of machine tool error percentages shows the proportion of different error items (positioning error, backlash error, perpendicularity error, and synchronization error) in the total error, reflecting the multi-axis error model's ability to fully capture machine tool error conditions. Figure 3 This is a comparison chart of the actual and theoretical trajectories of each machine tool axis; it shows how the deviation between the actual motion trajectory of each machine tool axis and the theoretical trajectory is corrected in real time during the machining process, demonstrating the technical effect of achieving real-time correction of the motion trajectory of each machine tool axis by gridding the machining surface and calculating the error compensation amount in combination with a multi-axis error model; Figure 4 This is a dynamic adjustment diagram of the error compensation amount of each axis of the machine tool. It shows how the error compensation amount is dynamically adjusted according to the actual position information and processing status information of each axis of the machine tool collected in real time during the processing process. It reflects the technical effect of dynamically adjusting the error compensation amount through the feedback control system and timely correcting the errors that occur during the processing.

[0049] The embodiment provides a high-precision surface processing method for a gantry CNC milling machine based on multi-axis linkage compensation, such as Figure 1-Figure 5 As shown, the following steps are included:

[0050] S1: Construct a multi-axis error model for a gantry CNC milling machine. Using laser interferometers, ballbars, and other measuring equipment, the positioning error, backlash error, perpendicularity error, and synchronization error of each axis of the gantry CNC milling machine are measured. This creates a comprehensive error model that includes machine tool geometry error, thermal deformation error, and multi-axis linkage error.

[0051] S2: Meshing the surface to be processed, dividing the surface to be processed into multiple small grid units according to the processing accuracy requirements, and determining the vertex coordinates of each grid unit;

[0052] S3: Calculate the error compensation amount of each vertex during multi-axis linkage machining based on the comprehensive error model and the vertex coordinates of each grid unit. The error compensation amount includes the displacement compensation amount and rotation compensation amount along each axis direction.

[0053] S4: Convert the calculated error compensation amount into motion compensation instructions for each axis of the machine tool, and perform real-time correction on the motion trajectory of each axis of the machine tool;

[0054] S5: The machined surface is machined using a layered milling method. During each layer of machining, the actual position information and machining status information of each axis of the machine tool are collected in real time. The actual position information is compared with the corrected theoretical position information through a feedback control system. The error compensation amount is dynamically adjusted based on the comparison result to further improve the machining accuracy.

[0055] S6: Repeat step S5 until the entire surface is processed.

[0056] By constructing a multi-axis error model to comprehensively measure various errors, an accurate basis is provided for error compensation; the surface is meshed and the vertex error compensation amount is calculated to achieve real-time correction of the motion trajectory of each axis of the machine tool; layered milling combined with real-time feedback to adjust the error compensation amount can continuously correct processing errors, and ultimately achieve comprehensive compensation for the multi-axis linkage errors of the gantry CNC milling machine, effectively improving the surface processing accuracy and surface quality.

[0057] Among them, in step S1, the specific process of establishing the comprehensive error model is:

[0058] First, the positioning error and backlash error of each axis at different positions are measured by laser interferometer, and the positioning error model and backlash error model of each axis are established;

[0059] Then, the ballbar is used to measure the contour error of multi-axis linkage, and the multi-axis linkage error model is established based on the geometric structure parameters of the machine tool.

[0060] Finally, by installing temperature sensors at key locations of the machine tool to monitor the temperature changes of the machine tool in real time, a thermal deformation error model is established. The above error models are then integrated to obtain a comprehensive error model that includes machine tool geometric error, thermal deformation error, and multi-axis linkage error.

[0061] The specific process of establishing a comprehensive error model is elaborated in detail, from the error measurement modeling of each axis to the multi-axis linkage error modeling, and then integrating the thermal deformation error model, so that the error model is more comprehensive and accurate, and can more accurately reflect the actual error status of the machine tool, thereby providing more reliable data support for subsequent error compensation, and improving the effectiveness of error compensation and machining accuracy.

[0062] Among them, in step S3, the method for calculating the error compensation amount of each vertex during multi-axis linkage machining is:

[0063] According to the comprehensive error model, the least square method is used to fit the error of each vertex to obtain the error compensation function. The displacement compensation and rotation compensation of each vertex along each axis direction during multi-axis linkage machining are calculated through the error compensation function.

[0064] The least squares method is used to fit the error to obtain the compensation function to calculate the error compensation amount. This method can more accurately determine the error compensation amount of each vertex based on the comprehensive error model, make the error compensation more in line with the actual processing error, improve the accuracy of error compensation, and thus improve the accuracy of surface processing.

[0065] The method is characterized in that, in step S4, the error compensation amount is converted into the motion compensation instruction of each axis of the machine tool by:

[0066] According to the kinematic principle of the machine tool, the calculated error compensation amount is converted into the pulse equivalent of each axis of the machine tool, and the corresponding motion compensation instruction is generated. The motion compensation instruction is sent to the servo drive device of each axis of the machine tool through the CNC system to realize real-time correction of the motion trajectory of each axis of the machine tool.

[0067] According to the kinematic principle of machine tools, the error compensation amount is converted into a pulse equivalent to generate a motion compensation instruction, ensuring that the compensation instruction can accurately control the motion of each axis of the machine tool, realize the precise correction of the motion trajectory of each axis of the machine tool, and make the machine tool process according to the corrected trajectory, effectively reducing the processing error and improving the processing accuracy.

[0068] Among them, in step S5, the method for real-time acquisition of the actual position information and processing status information of each axis of the machine tool is:

[0069] The actual position information of each axis is collected in real time by the grating ruler installed on each axis of the machine tool, and the cutting force, vibration and other processing status information during the processing are collected by force sensors, vibration sensors, etc.

[0070] By using the grating ruler to collect the actual position information of the axis, and the force sensor and vibration sensor to collect the processing status information, key data of the machine tool processing process can be obtained in real time, providing a data basis for subsequent adjustment of the error compensation amount according to the actual processing conditions, thereby correcting the processing error in time and ensuring the processing accuracy and surface quality.

[0071] In step S5, the actual position information is compared with the corrected theoretical position information through the feedback control system, and the error compensation amount is dynamically adjusted according to the comparison result.

[0072] The collected actual position information is compared with the corrected theoretical position information to calculate the position deviation. According to the position deviation and the preset control algorithm, the error compensation amount is dynamically adjusted to make the actual motion trajectory of each axis of the machine tool closer to the corrected theoretical motion trajectory.

[0073] By comparing the actual and theoretical position information through the feedback control system and dynamically adjusting the error compensation amount according to the deviation and control algorithm, the errors in the processing process can be corrected in real time, so that the actual motion trajectory of each axis of the machine tool continues to approach the theoretical trajectory, continuously improving the processing accuracy and surface quality.

[0074] Among them, the high-precision surface processing method of the gantry CNC milling machine based on multi-axis linkage compensation also includes: preheating the gantry CNC milling machine before processing to make the machine tool reach a thermal equilibrium state to reduce the impact of thermal deformation errors on processing accuracy.

[0075] Preheating the machine tool before processing to reach a thermal equilibrium state can reduce errors caused by thermal deformation of the machine tool, avoid the adverse effects of thermal deformation errors on processing accuracy, provide a stable machine tool state foundation for high-precision processing, and improve processing accuracy.

[0076] Among them, the high-precision surface processing method of the gantry CNC milling machine based on multi-axis linkage compensation also includes: during the processing process, according to the characteristics of the processing material and processing requirements, reasonably selecting tool parameters and cutting parameters to improve processing efficiency and surface quality.

[0077] Reasonable selection of tool parameters and cutting parameters according to the characteristics and requirements of the processing material can optimize the processing process, reduce processing defects caused by improper tools and cutting parameters, improve processing efficiency, and at the same time ensure the processing surface quality and achieve efficient and high-precision processing.

[0078] This embodiment also provides a high-precision curved surface machining system for a gantry CNC milling machine based on multi-axis linkage compensation, which is used to implement the above-mentioned high-precision curved surface machining method for a gantry CNC milling machine based on multi-axis linkage compensation, including: an error measurement module, an error measurement module, a data processing module, and a machining control module, wherein:

[0079] The error measurement module is used to measure the positioning error, backlash error, verticality error of each axis of the gantry CNC milling machine, as well as the synchronization error during multi-axis linkage;

[0080] The error modeling module is used to establish a comprehensive error model including machine tool geometric error, thermal deformation error and multi-axis linkage error based on the measurement results of the error measurement module;

[0081] The data processing module is used to perform gridding on the machined surface, calculate the error compensation amount of each grid unit vertex according to the comprehensive error model, and convert the error compensation amount into motion compensation instructions for each axis of the machine tool;

[0082] The machining control module is used to control the motion of each axis of the machine tool according to the motion compensation instruction, use the layered milling method to process the machining surface, and dynamically adjust the error compensation amount through the feedback control system.

[0083] The machining system is divided into error measurement, modeling, data processing and machining control modules. Each module works together to form a complete machining control process from error measurement and analysis to error compensation control. It can systematically realize the compensation of multi-axis linkage errors of gantry CNC milling machines and control the machining process, thereby improving machining accuracy and system stability.

[0084] Among them, the error measurement module includes a laser interferometer, a ballbar, a temperature sensor, a grating scale, a force sensor and a vibration sensor.

[0085] It is clear that the error measurement module contains multiple sensors. Multiple sensors work together to comprehensively measure machine tool errors and processing status information from different dimensions, providing richer and more accurate data for error modeling and processing control, making error compensation and processing control more precise and effective, and improving the performance and processing accuracy of the processing system.

[0086] Among them, in step S3, the calculation of the error compensation amount adopts the multi-axis linkage comprehensive error compensation equation, which is expressed as:

[0087] A i =E i (B i +C i +F i ·D i +G i ·H i )

[0088] in:

[0089] A_i is the compensation vector of the i-th vertex, calculated by equation and updated in real time;

[0090] B_i is the geometric error vector, measured using a laser interferometer;

[0091] C_i is the thermal deformation error vector, which is calculated using the temperature sensor + thermal model;

[0092] D_i is the multi-axis linkage synchronization error vector, obtained by ballbar measurement + kinematic transformation

[0093] E_i is the error coupling coefficient matrix, which is the experimental calibration of machine tool structural parameters;

[0094] F_i is the linkage error conversion matrix, which is constructed based on the machine tool kinematic model;

[0095] G_i is the dynamic feedback gain coefficient, adaptive algorithm (based on sensor data);

[0096] H_i is the real-time feedback error vector, collected by the grating ruler / force sensor.

[0097] Example: Take five-axis machining as an example:

[0098] 1. Parameter assignment:

[0099] B_i=[0.02,0.015,0] T (X-axis positioning error, unit: μm);

[0100] C_i=[0.03,0.02,0.01] T (thermal deformation error, unit: μm);

[0101] D_i=[0.01,0,-0.005,0.002,0] T (linkage error, unit rad);

[0102] E_i=diag(1,1.2,1,1.5,1.3)(error coupling matrix);

[0103] G_i=0.8 (feedback gain);

[0104] H_i=[0.005,-0.003,0,0,0] T (Feedback error, unit: μm).

[0105] 2. Calculation process:

[0106] Assume that the compensation amount of a certain axis after F_i conversion is 0.01, after matrix operation:

[0107] X-axis compensation: (0.02+0.03+0.01+0.8×0.005)×1=0.054μm;

[0108] A-axis compensation: 0.002×1.5=0.003rad.

[0109] The technical effect of the multi-axis linkage comprehensive error compensation equation is as follows:

[0110] The multi-axis linkage comprehensive error compensation equation is expressed as E i (B i +C i +F i ·D i ) replaces the traditional single error superposition and integrates multiple error coupling effects; G i ·H i A closed loop of "compensation-feedback-correction" is implemented to resolve dynamic error defects caused by static compensation. Parameters can be acquired through a laser interferometer / ballbar without hardware modification, making it suitable for mainstream machine tools.

[0111] Multi-error fusion: unified compensation of geometric, thermal deformation, and linkage synchronization errors, significantly improving accuracy;

[0112] Dynamic correction: Cutting vibration is suppressed in real time through G_i and H_i, and surface roughness is significantly reduced;

[0113] Error coupling control: E_i and F_i characterize the influence of inter-axis errors, and the contour error is greatly reduced.

[0114] The working principle of the multi-axis linkage comprehensive error compensation equation is as follows: Figure 5 shown.

[0115] The specific examples of the high-precision surface machining method of the gantry CNC milling machine based on multi-axis linkage compensation are as follows:

[0116] Example 1: Taking a certain type of gantry CNC milling machine to process the curved surface of an aircraft engine blade as an example, the specific implementation steps are as follows:

[0117] 1. Using a laser interferometer and a ballbar, we measured the five axes (X, Y, Z, A, and B) of a gantry CNC milling machine. We measured positioning error, backlash error, perpendicularity error, and synchronization error during the five-axis linkage. Furthermore, we installed temperature sensors in key locations, such as the machine's spindle box and guide rails, to monitor temperature changes in real time. Based on these measurement results, we developed a comprehensive error model that incorporates machine geometry error, thermal deformation error, and five-axis linkage error.

[0118] 2. Divide the surface of the aircraft engine blade into tiny grid units of 0.1mm×0.1mm according to the processing accuracy requirements, and determine the vertex coordinates of each grid unit.

[0119] 3. Based on the established comprehensive error model and the coordinates of each grid unit vertex, the least squares method is used to calculate the displacement compensation and rotation compensation of each vertex along each axis during five-axis linkage machining.

[0120] 4. According to the kinematic principles of the machine tool, the calculated error compensation amount is converted into the pulse equivalent of each axis of the machine tool, and the corresponding motion compensation instructions are generated. The motion compensation instructions are sent to the servo drive devices of each axis of the machine tool through the CNC system to perform real-time corrections on the motion trajectory of each axis of the machine tool.

[0121] 5. The blade surface is machined using layered milling, with each layer milling to a depth of 0.5 mm. During each layer, a scale installed on each axis collects real-time position information for each axis. Force and vibration sensors collect cutting force and vibration information during machining. This collected actual position information is compared with the corrected theoretical position information to calculate the position deviation. The error compensation is dynamically adjusted based on a pre-set PID control algorithm to ensure that the actual motion trajectory of each axis is closer to the corrected theoretical trajectory.

[0122] 6. Repeat step 5 until the entire blade surface is processed. After testing, the accuracy of the processed blade surface meets the design requirements and the surface quality is good.

[0123] Example 2: Taking the processing of a certain automobile mold surface as an example, the processing method of the present invention is used for processing. First, the gantry CNC milling machine is preheated to allow the machine tool to reach a thermal equilibrium state. Then, error measurement, modeling, data processing and processing control are performed according to the steps of the above embodiment 1. During the processing, according to the characteristics of the mold material, suitable tools and cutting parameters are selected, such as a vertical milling cutter with a tool diameter of 10 mm, a cutting speed of 80 m / min, and a feed speed of 100 mm / min. Through the processing method of the present invention, the processing accuracy and surface quality of the automobile mold surface are effectively improved, and the processing efficiency is also improved to a certain extent.

[0124] In summary, the high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation provided in this embodiment has the following advantages:

[0125] The present invention focuses on high-precision surface processing of gantry CNC milling machines, and through multi-dimensional technological innovation, it has achieved a significant improvement in processing accuracy and efficiency. In terms of error processing, a comprehensive error model is constructed to accurately cover various errors such as geometry, thermal deformation and multi-axis linkage, providing a solid data basis for compensation; during the processing, surface meshing and layered milling are combined with real-time feedback to dynamically adjust the error compensation amount, effectively correct the processing error, and improve the surface processing accuracy and surface quality; at the same time, factors such as machine tool preheating, tool and cutting parameter selection are taken into consideration to reduce thermal deformation errors, optimize the processing process, and improve processing efficiency. Through a systematic technical solution, the present invention comprehensively solves the problems of insufficient multi-axis linkage error compensation and difficulty in ensuring accuracy in traditional processing, and meets the stringent requirements of modern manufacturing for high-precision processing.

[0126] How it works

[0127] 1. Error modeling principle: Using laser interferometers, ballbars, and other measuring equipment, we collect data on the positioning error, backlash error, perpendicularity error, and multi-axis synchronization error of each axis of the gantry CNC milling machine. Combined with thermal deformation data monitored by temperature sensors, these various error models are integrated through a specific algorithm to construct a comprehensive error model. This model accurately describes the error status of the machine tool during machining.

[0128] 2. Error compensation principle: After the machining surface is meshed, the least squares method is used to calculate the error compensation amount of each mesh vertex according to the comprehensive error model, and it is converted into motion compensation instructions for each axis of the machine tool. The motion trajectory of each axis of the machine tool is corrected to make the actual motion trajectory of the machine tool closer to the theoretical trajectory, thereby realizing multi-axis linkage error compensation.

[0129] 3. Dynamic adjustment principle: During the layered milling process, the actual position and processing status information of each axis of the machine tool is collected in real time through grating scales, force sensors, vibration sensors, etc., and compared with the corrected theoretical position information. The deviation is calculated according to the preset control algorithm and the error compensation amount is dynamically adjusted to continuously optimize the processing accuracy.

[0130] How to use

[0131] 1. Preparation stage:

[0132] Preheat the gantry CNC milling machine to reach thermal equilibrium and reduce thermal deformation errors.

[0133] According to the characteristics and requirements of the processing material, reasonably select the tool parameters (such as tool type, diameter, material, etc.) and cutting parameters (such as cutting speed, feed rate, cutting depth, etc.).

[0134] Using laser interferometers, ballbars, temperature sensors and other equipment, the positioning errors, backlash errors, verticality errors, multi-axis linkage synchronization errors and thermal deformation errors of each axis of the machine tool are measured to construct a comprehensive error model.

[0135] 2. Data processing stage:

[0136] The surface to be processed is divided into tiny grid units according to the processing accuracy requirements, and the vertex coordinates of each grid unit are determined.

[0137] According to the comprehensive error model and the mesh vertex coordinates, the least squares method is used to calculate the error compensation of each vertex, including the displacement compensation and rotation compensation along each axis.

[0138] According to the kinematic principle of machine tools, the error compensation amount is converted into the pulse equivalent of each axis of the machine tool to generate motion compensation instructions.

[0139] 3. Processing stage:

[0140] The machined surface is processed by layered milling. During each layer of processing, the actual position information of each axis is collected in real time through the grating ruler, and the processing status information is collected through the force sensor and vibration sensor.

[0141] The feedback control system compares the actual position information with the corrected theoretical position information, calculates the position deviation, dynamically adjusts the error compensation amount according to the control algorithm, and corrects the motion trajectory of each axis of the machine tool until the entire surface processing is completed.

[0142] The above are only preferred embodiments of the present invention and do not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-precision surface machining method for a gantry CNC milling machine based on multi-axis linkage compensation, characterized in that: The following steps are involved: S1: Construct a multi-axis error model for a gantry CNC milling machine. Using laser interferometers and ballbar measuring equipment, the positioning error, backlash error, perpendicularity error, and synchronization error of each axis of the gantry CNC milling machine are measured. This creates a comprehensive error model that includes machine tool geometry error, thermal deformation error, and multi-axis linkage error. S2: Meshing the surface to be processed, dividing the surface to be processed into multiple small grid units according to the processing accuracy requirements, and determining the vertex coordinates of each grid unit; S3: Calculating the error compensation amount of each vertex during multi-axis linkage machining based on the comprehensive error model and the vertex coordinates of each grid unit, wherein the error compensation amount includes the displacement compensation amount and the rotation compensation amount along each axis direction; S4: Convert the calculated error compensation amount into motion compensation instructions for each axis of the machine tool, and perform real-time correction on the motion trajectory of each axis of the machine tool; S5: The machined surface is machined using a layered milling method. During each layer of machining, the actual position information and machining status information of each axis of the machine tool are collected in real time. The actual position information is compared with the corrected theoretical position information through a feedback control system. The error compensation amount is dynamically adjusted based on the comparison result to further improve the machining accuracy. S6: Repeat step S5 until the entire surface is processed.

2. The high-precision surface processing method of a gantry CNC milling machine based on multi-axis linkage compensation according to claim 1 is characterized in that: In step S1, the specific process of establishing the comprehensive error model is: First, the positioning error and backlash error of each axis at different positions are measured by laser interferometer, and the positioning error model and backlash error model of each axis are established; Then, the ballbar is used to measure the contour error of multi-axis linkage, and the multi-axis linkage error model is established based on the geometric structure parameters of the machine tool. Finally, by installing temperature sensors at key locations of the machine tool to monitor the temperature changes of the machine tool in real time, a thermal deformation error model is established. The above error models are then integrated to obtain a comprehensive error model that includes machine tool geometric error, thermal deformation error, and multi-axis linkage error.

3. The high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation according to claim 1 is characterized in that: In step S3, the method for calculating the error compensation amount of each vertex during multi-axis linkage machining is: According to the comprehensive error model, the least squares method is used to fit the error of each vertex to obtain an error compensation function, and the displacement compensation and rotation compensation of each vertex along each axis direction during multi-axis linkage machining are calculated using the error compensation function.

4. The high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation according to claim 1 is characterized in that: In step S4, the method for converting the error compensation amount into the motion compensation instructions of each axis of the machine tool is: According to the kinematic principle of the machine tool, the calculated error compensation amount is converted into the pulse equivalent of each axis of the machine tool, and the corresponding motion compensation instruction is generated. The motion compensation instruction is sent to the servo drive device of each axis of the machine tool through the CNC system to realize real-time correction of the motion trajectory of each axis of the machine tool.

5. The high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation according to claim 1 is characterized in that: In step S5, the method for real-time acquisition of the actual position information and processing status information of each axis of the machine tool is: The actual position information of each axis is collected in real time through the grating ruler installed on each axis of the machine tool, and the cutting force and vibration processing status information during the processing are collected through the force sensor and vibration sensor.

6. The high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation according to claim 1 is characterized in that: In step S5, the method of comparing the actual position information with the corrected theoretical position information through the feedback control system and dynamically adjusting the error compensation amount according to the comparison result is: The collected actual position information is compared with the corrected theoretical position information to calculate the position deviation. According to the position deviation and the preset control algorithm, the error compensation amount is dynamically adjusted to make the actual motion trajectory of each axis of the machine tool closer to the corrected theoretical motion trajectory.

7. The high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation according to claim 1, characterized in that: Also includes: Before processing, the gantry CNC milling machine is preheated to allow the machine to reach a thermal equilibrium state to reduce the impact of thermal deformation errors on processing accuracy.

8. The high-precision surface machining method of a gantry CNC milling machine based on multi-axis linkage compensation according to claim 1, characterized in that: Also includes: During the machining process, tool parameters and cutting parameters should be reasonably selected according to the characteristics of the machining material and machining requirements to improve machining efficiency and surface quality.

9. A high-precision surface processing system for a gantry CNC milling machine based on multi-axis linkage compensation, characterized in that: The method for high-precision surface machining of a gantry CNC milling machine based on multi-axis linkage compensation according to any one of claims 1 to 8 comprises: Error measurement module, used to measure the positioning error, backlash error, verticality error of each axis of the gantry CNC milling machine, and synchronization error during multi-axis linkage; An error modeling module is used to establish a comprehensive error model including machine tool geometric error, thermal deformation error and multi-axis linkage error based on the measurement results of the error measurement module; a data processing module for performing gridding processing on the machined surface, calculating the error compensation amount of each grid unit vertex according to the comprehensive error model, and converting the error compensation amount into motion compensation instructions for each axis of the machine tool; The processing control module is used to control the movement of each axis of the machine tool according to the motion compensation instruction, process the processing surface by layered milling, and dynamically adjust the error compensation amount through the feedback control system.

10. The high-precision curved surface machining system of a gantry CNC milling machine based on multi-axis linkage compensation according to claim 9, characterized in that: The error measurement module includes a laser interferometer, a ballbar, a temperature sensor, a grating scale, a force sensor and a vibration sensor.

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