Multi-axis numerical control machining tool path generation method based on part model

Abstract

The invention relates to the technical field of program control, in particular to a multi-axis numerical control machining tool path generation method based on a part model. The method comprises the following steps: acquiring three-dimensional model data of a part; constructing a triangular mesh model based on the three-dimensional model data of the part, and performing adaptive mesh generation on the triangular mesh model to generate a refined triangular mesh model; calculating the normal vector of each triangle based on the refined triangular mesh model to obtain triangular mesh normal vector data; according to the refined triangular mesh model, preliminary tool path design is carried out, and preliminary tool path data are obtained. According to the method, through refined path design, cutter posture optimization, collision detection and path smoothing, the precision, safety and efficiency of multi-axis numerical control machining are improved, and reliable guarantee is provided for machining of complex parts.

Description

Technical Field

[0001] The invention relates to the technical field of program control, and in particular to a multi-axis CNC machining tool path generation method based on a part model. Background Art

[0002] In multi-axis CNC machining, the accuracy of tool path generation directly affects the machining quality. Most current tool path generation methods rely on empirical formulas or simple geometric models for path planning, and fail to fully consider the three-dimensional complexity of parts and the changes in tool posture during machining. Especially when processing parts with complex surfaces or complex geometric shapes, traditional methods often cannot accurately fit the part surface, resulting in large errors in the tool path, which in turn affects the machining accuracy and surface quality. Tool posture is a key factor in multi-axis CNC machining and determines the contact state between the tool and the workpiece. In current tool path generation methods, the calculation and adjustment of tool posture mostly rely on manual settings, which are highly subjective and limited. Especially when facing complex geometric shapes, traditional tool posture optimization methods often cannot provide accurate posture adjustment solutions, resulting in poor contact between the tool and the part surface, and even sudden posture changes and uneven tool force. Summary of the invention

[0003] Based on this, it is necessary for the present invention to provide a multi-axis CNC machining tool path generation method based on a part model to solve at least one of the above technical problems.

[0004] To achieve the above purpose, a multi-axis CNC machining tool path generation method based on a part model comprises the following steps:

[0005] Step S1: Acquire the three-dimensional model data of the part; construct a triangular mesh model based on the three-dimensional model data of the part, and perform adaptive meshing on the triangular mesh model to generate a refined triangular mesh model;

[0006] Step S2: Calculate the normal vector of each triangle based on the refined triangular mesh model to obtain the normal vector data of the triangular mesh;

[0007] Step S3: Perform preliminary tool path design based on the refined triangular mesh model to obtain preliminary tool path data;

[0008] Step S4: optimizing the tool posture of the preliminary tool path data using the normal vector data of the triangular mesh to obtain optimized tool posture data;

[0009] Step S5: performing collision detection based on the preliminary tool path data and the optimized tool posture data, and optimizing and adjusting the preliminary tool path data based on the collision detection result to obtain collision optimized tool path data;

[0010] Step S6: Smoothly optimize the collision optimized tool path data and convert the tool path code to obtain the final optimized tool path data.

[0011] The present invention can accurately reflect the geometric shape and surface features of the part by acquiring the three-dimensional model data of the part and constructing a refined triangular mesh model based on these data. Adaptive meshing can be optimized according to the complexity of different areas to ensure that the density of the mesh in the key area is high enough, thereby improving the accuracy of tool path generation. This provides detailed and accurate basic data for subsequent tool path design and optimization. By calculating the normal vector of each triangle in the refined triangular mesh model, accurate normal direction data can be provided for the design of the tool path. The calculation of the normal vector is crucial for tool posture optimization, which ensures that the tool can correctly contact the part surface during the processing and effectively improves the processing accuracy and surface quality. Preliminary tool path design is performed on the basis of the refined triangular mesh model, and a reasonable processing path can be generated according to the shape and features of the part surface. This process ensures that the tool path can cover the entire part surface, meet the processing requirements, and provide a preliminary path reference for subsequent tool posture optimization and collision detection. Using the triangular mesh normal vector data to perform posture optimization on the preliminary tool path can ensure that the tool cuts at the correct angle and direction during the processing. Through this optimization, unnecessary adjustments or position errors of the tool at the path changes are avoided, further improving the stability and quality of the processing. By detecting collisions and optimizing the tool path, it can be ensured that the tool will not collide with parts, fixtures and other components during the processing. Collision optimization not only improves the safety of the processing process, but also avoids damage to the machine tool, reduces errors and unexpected downtime during processing. By smoothly optimizing the tool path and converting the path into tool path code, it is ensured that the tool moves along a smooth and safe path during the processing process, reducing vibration and tool wear. The final optimized tool path data generated can be directly used for the operation of CNC machine tools and ensure the accuracy and efficiency of processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments thereof made with reference to the following drawings:

[0013] Figure 1 A schematic diagram of the steps of the method for generating tool paths for multi-axis CNC machining based on a part model of the present invention;

[0014] Figure 2 for Figure 1 Detailed step flow diagram of step S1;

[0015] Figure 3 for Figure 1Detailed step flow chart of step S2 in FIG. DETAILED DESCRIPTION

[0016] The technical method of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by technicians in this field without creative work are within the scope of protection of the present invention.

[0017] In addition, the accompanying drawings are only schematic illustrations of the present invention and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. The functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor methods and / or microcontroller methods.

[0018] It should be understood that, although the terms "first", "second", etc. may be used herein to describe various units, these units should not be limited by these terms. These terms are used only to distinguish one unit from another unit. For example, without departing from the scope of the exemplary embodiments, the first unit may be referred to as the second unit, and similarly the second unit may be referred to as the first unit. The term "and / or" used herein includes any and all combinations of one or more of the listed associated items.

[0019] To achieve this, please refer to Figures 1 to 3 The present invention provides a method for generating tool paths for multi-axis CNC machining based on a part model, the method comprising the following steps:

[0020] Step S1: Acquire the three-dimensional model data of the part; construct a triangular mesh model based on the three-dimensional model data of the part, and perform adaptive meshing on the triangular mesh model to generate a refined triangular mesh model;

[0021] Step S2: Calculate the normal vector of each triangle based on the refined triangular mesh model to obtain the normal vector data of the triangular mesh;

[0022] Step S3: Perform preliminary tool path design based on the refined triangular mesh model to obtain preliminary tool path data;

[0023] Step S4: optimizing the tool posture of the preliminary tool path data using the normal vector data of the triangular mesh to obtain optimized tool posture data;

[0024] Step S5: performing collision detection based on the preliminary tool path data and the optimized tool posture data, and optimizing and adjusting the preliminary tool path data based on the collision detection result to obtain collision optimized tool path data;

[0025] Step S6: Smoothly optimize the collision optimized tool path data and convert the tool path code to obtain the final optimized tool path data.

[0026] In the embodiment of the present invention, reference Figure 1 The above is a schematic flow chart of the steps of a method for generating a tool path for multi-axis CNC machining based on a part model of the present invention. In this example, the method for generating a tool path for multi-axis CNC machining based on a part model includes the following steps:

[0027] Step S1: Acquire the three-dimensional model data of the part; construct a triangular mesh model based on the three-dimensional model data of the part, and perform adaptive meshing on the triangular mesh model to generate a refined triangular mesh model;

[0028] The embodiment of the present invention imports or generates the three-dimensional model data of the part to be processed through computer-aided design (CAD) software or other three-dimensional modeling tools. After the import is completed, the three-dimensional model data of the part is preliminarily checked to ensure data integrity and error-free. Based on the acquired three-dimensional model data, a preliminary triangular mesh model is constructed using a meshing algorithm (such as Delaunay triangulation or marching cubes algorithm). The triangular mesh model discretizes the three-dimensional geometric surface of the part into a geometric representation composed of multiple triangular units. The preliminarily constructed triangular mesh model is adaptively meshed. Specifically, the size and density of the mesh unit are adjusted according to the local features of the part's geometric surface. In areas with drastic geometric changes (such as sharp corners or surfaces with large curvature), the mesh units are encrypted to improve the resolution; in areas with gentle geometric changes, the number of mesh units is appropriately reduced to reduce the computational complexity. During the meshing process, the Laplace smoothing algorithm or other smoothing techniques can be used to further optimize the mesh quality to avoid the appearance of triangular units that are too long or too thin. Finally, a refined triangular mesh model that meets the machining accuracy requirements is generated.

[0029] Step S2: Calculate the normal vector of each triangle based on the refined triangular mesh model to obtain the normal vector data of the triangular mesh;

[0030] The embodiment of the present invention calculates the normal vector of each triangle in the refined triangular mesh model according to the vertex coordinates of the triangle by the vector cross product method. The calculated normal vector is normalized so that its length is unit length. The direction consistency of the normal vectors of all triangles is checked. By judging whether the normal vector is facing the outside of the model, if some normal vectors are found to have abnormal directions, they are adjusted by reverse operation (i.e. taking negative values) to ensure the consistency of the normal direction. The normalized normal vector data is bound to the corresponding triangular unit index to generate the triangular mesh normal vector data.

[0031] Step S3: Perform preliminary tool path design based on the refined triangular mesh model to obtain preliminary tool path data;

[0032] The embodiment of the present invention partitions the machining surface of the part based on the refined triangular mesh model, and determines the machining area and path of the tool in combination with the machining process requirements. The design of the preliminary tool path path must follow the comprehensive optimization principle of machining efficiency and machining quality, and generate path data that conforms to the geometric characteristics of the machining surface. The machining surface is partitioned according to the geometric characteristics of the refined triangular mesh model (such as curvature change or normal direction). A refined machining path is designed for areas with large curvature or complex features; a relatively simplified machining path is designed for areas with small curvature or gentle geometric changes. Regular sampling or adaptive sampling of tool path points is performed on the machining surface. Regular sampling is uniform sampling along the machining direction according to a fixed step size; adaptive sampling is to increase the sampling point density for areas with large curvature changes and reduce the sampling point density for areas with small changes, thereby balancing machining accuracy and computational efficiency. The sampling points are connected by an interpolation algorithm to generate a continuous preliminary tool path path. Specifically, a straight line segment, an arc segment or other smooth curve can be used as the tool path path form to ensure the continuity and operability of the tool path in the machining area. The initially generated tool path is optimized to eliminate overly dense path points to reduce redundant calculations; the position of the path points is adjusted to make it fit the processing surface more closely and reduce processing errors. Finally, the initial tool path data is generated.

[0033] Step S4: optimizing the tool posture of the preliminary tool path data using the normal vector data of the triangular mesh to obtain optimized tool posture data;

[0034] The embodiment of the present invention uses triangular mesh normal vector data and preliminary tool path data as input. The triangular mesh normal vector data provides geometric direction information of each triangular surface, and the preliminary tool path data provides the preliminary position and path order of the tool path points. According to the processing technology requirements, the target of tool posture optimization is determined, and the target includes but is not limited to adjusting the tool posture so that the cutting part of the tool fits the processing surface to improve the processing accuracy; ensuring that the non-cutting part of the tool does not interfere or collide with the processing surface or other workpiece parts; optimizing the continuity of the tool posture, avoiding sudden angle changes, and improving processing stability. Based on the triangular mesh normal vector data and the preliminary tool path data, the tool posture is optimized. Using the triangular mesh normal vector corresponding to the tool path path point, the main axis direction of the tool is set to be consistent with the normal vector direction, and the tool posture is preliminarily adjusted. According to the motion limit of the machine tool (such as the inclination angle range of the tool spindle), the preliminarily adjusted tool posture is constrained to ensure that the tool posture is within the allowable range of the machine tool. The tool posture of continuous path points is smoothed by using an interpolation algorithm to reduce the fluctuation of posture changes and ensure the stability of the processing process. Verify the optimized tool posture, the fit between the tool posture and the geometric features of the machining surface; whether the tool posture meets the machine tool motion restrictions; and the path smoothness and continuity after posture adjustment. If the verification result does not meet the requirements, readjust the optimization parameters according to the optimization goal and repeat the optimization process until the requirements are met. Associate the optimized tool posture data with the corresponding tool path points to generate structured optimized tool posture data.

[0035] Step S5: performing collision detection based on the preliminary tool path data and the optimized tool posture data, and optimizing and adjusting the preliminary tool path data based on the collision detection result to obtain collision optimized tool path data;

[0036] The embodiment of the present invention uses preliminary tool path data and optimized tool posture data as input. The preliminary tool path data provides the position sequence of tool path points, and the optimized tool posture data provides the spatial direction information of the tool at each tool path point. The tool is regarded as a geometric entity (such as a cylinder, a cone or a complex tool model), and the overlapping area between the tool and the mesh model is detected in combination with the refined triangular mesh model of the part. The motion path of the tool posture is analyzed to ensure that the tool and the part surface maintain a reasonable safety distance to avoid dynamic collisions caused by rapid posture changes. According to the tool path point and the corresponding tool posture data, the position and direction of the tool at each path point are mapped to the refined triangular mesh model of the part, and the spatial relationship between the tool shape and the part model is calculated. If it is found that the tool shape overlaps with the triangular surface of the part model, the collision point and its corresponding tool path point index are recorded. The severity of the collision is evaluated according to the collision depth or contact area, and the specific tool path point that needs to be optimized and adjusted is determined. The preliminary tool path data is optimized and adjusted for the detected collision point. The path point where the collision occurs is offset by a certain distance along the normal direction to ensure a safe gap between the tool and the part surface. Without changing the position of the tool path point, the collision can be reduced or eliminated by slightly adjusting the tool direction. For the path segments where collisions occur continuously, the path is redesigned in combination with the local triangular mesh features to ensure that the tool can avoid the collision area. The optimized tool path data is re-checked for collisions to ensure that all path points meet the safety requirements. If there is still a collision, the path point or posture is further adjusted until the requirements are met. The tool path data after collision detection and optimization is stored in a structured data format to generate collision optimized tool path data.

[0037] Step S6: Smoothly optimize the collision optimized tool path data and convert the tool path code to obtain the final optimized tool path data.

[0038] The embodiment of the present invention performs smoothing optimization on the collision optimized tool path data, and smoothes the spatial position of the path points and the tool posture through an interpolation algorithm to eliminate the mutations between the path points and improve the path continuity and processing stability; then the optimized tool path data is converted into a CNC machining code recognizable by the machine tool, specifically including encoding the path points and tool posture data into an instruction format that meets the CNC machining standard (such as G code or APT code), and verifying the compatibility of the instructions, and finally outputting the final optimized tool path data for actual machining.

[0039] The present invention can accurately reflect the geometric shape and surface features of the part by acquiring the three-dimensional model data of the part and constructing a refined triangular mesh model based on these data. Adaptive meshing can be optimized according to the complexity of different areas to ensure that the density of the mesh in the key area is high enough, thereby improving the accuracy of tool path generation. This provides detailed and accurate basic data for subsequent tool path design and optimization. By calculating the normal vector of each triangle in the refined triangular mesh model, accurate normal direction data can be provided for the design of the tool path. The calculation of the normal vector is crucial for tool posture optimization, which ensures that the tool can correctly contact the part surface during the processing and effectively improves the processing accuracy and surface quality. Preliminary tool path design is performed on the basis of the refined triangular mesh model, and a reasonable processing path can be generated according to the shape and features of the part surface. This process ensures that the tool path can cover the entire part surface, meet the processing requirements, and provide a preliminary path reference for subsequent tool posture optimization and collision detection. Using the triangular mesh normal vector data to perform posture optimization on the preliminary tool path can ensure that the tool cuts at the correct angle and direction during the processing. Through this optimization, unnecessary adjustments or position errors of the tool at the path changes are avoided, further improving the stability and quality of the processing. By detecting collisions and optimizing the tool path, it can be ensured that the tool will not collide with parts, fixtures and other components during the processing. Collision optimization not only improves the safety of the processing process, but also avoids damage to the machine tool, reduces errors and unexpected downtime during processing. By smoothly optimizing the tool path and converting the path into tool path code, it is ensured that the tool moves along a smooth and safe path during the processing process, reducing vibration and tool wear. The final optimized tool path data generated can be directly used for the operation of CNC machine tools and ensure the accuracy and efficiency of processing.

[0040] Preferably, step S1 comprises the following steps:

[0041] Step S11: acquiring the three-dimensional model data of the part, and performing standardization processing on the three-dimensional model data of the part to obtain standardized three-dimensional model data;

[0042] Step S12: discretizing the surface of the part according to the standardized three-dimensional model data to obtain discretized data of the surface of the part;

[0043] Step S13: constructing a triangular mesh model using the discretized data of the part surface to obtain a preliminary triangular mesh model;

[0044] Step S14: performing discrete curvature calculation on the preliminary three-dimensional mesh model to obtain part surface curvature data;

[0045] Step S15: Adaptively meshing the preliminary three-dimensional mesh model based on the part surface curvature data to obtain an adaptive triangular mesh model;

[0046] Step S16: Optimizing the mesh quality of the adaptive triangular mesh model to obtain a refined triangular mesh model.

[0047] As an embodiment of the present invention, refer to Figure 2 As shown, Figure 1 Detailed step flow diagram of step S1 in the embodiment of the present invention, step S1 includes the following steps:

[0048] Step S11: acquiring the three-dimensional model data of the part, and performing standardization processing on the three-dimensional model data of the part to obtain standardized three-dimensional model data;

[0049] The embodiment of the present invention obtains the three-dimensional model data of a part through a three-dimensional scanner or computer-aided design (CAD) software, and standardizes the obtained three-dimensional model data, including unifying the size unit, coordinate system and topological structure of the model, while removing redundant data and repairing geometric defects to ensure the integrity and consistency of the model data, thereby generating standardized three-dimensional model data.

[0050] Step S12: discretizing the surface of the part according to the standardized three-dimensional model data to obtain discretized data of the surface of the part;

[0051] The embodiment of the present invention discretizes the surface of a part based on standardized three-dimensional model data, and extracts feature point data of the part surface using uniform sampling or adaptive sampling methods, ensuring that the sampling points can cover the key geometric areas of the model surface, and generates discretized data of the part surface based on the complexity of the part and the processing accuracy requirements, laying the foundation for subsequent triangular mesh model construction.

[0052] Step S13: constructing a triangular mesh model using the discretized data of the part surface to obtain a preliminary triangular mesh model;

[0053] The embodiment of the present invention constructs a preliminary triangular mesh model based on the discretized data of the part surface using a triangular mesh generation algorithm. An appropriate mesh partitioning method is selected, such as Delaunay triangulation or a partitioning algorithm based on a Voronoi diagram, to connect the discretized point set into a triangular mesh. During the mesh construction process, it is ensured that the nodes and boundaries of the mesh can accurately cover the surface of the part, and the uniformity and rationality of the mesh are maintained for subsequent processing. At the same time, overlapping or redundant data are processed to generate a preliminary triangular mesh model.

[0054] Step S14: performing discrete curvature calculation on the preliminary three-dimensional mesh model to obtain part surface curvature data;

[0055] The embodiment of the present invention performs discrete curvature calculation on each triangle in the mesh according to the preliminary three-dimensional mesh model. The geometric characteristics of the part surface are analyzed by calculating the curvature value on the surface of each triangle. Common curvature calculation methods include using local fitting methods (such as least squares method) to estimate the curvature of each triangle, or extrapolating based on the boundary curvature and the normal direction of the face. The part surface curvature data is obtained by calculation.

[0056] Step S15: Adaptively meshing the preliminary three-dimensional mesh model based on the part surface curvature data to obtain an adaptive triangular mesh model;

[0057] The embodiment of the present invention performs adaptive meshing of the preliminary three-dimensional mesh model based on the surface curvature data of the part. According to the change of the surface curvature and the processing requirements of the part, a finer mesh is used in the area with larger curvature, while a coarser mesh is used in the area with smaller curvature or flat. Through this adaptive partitioning method, it is possible to ensure that the mesh density is accurately represented in key areas (such as complex surfaces or detailed parts) while avoiding wasting computing resources in simple areas. The size of the mesh is dynamically adjusted through algorithm optimization to obtain an adaptive triangular mesh model.

[0058] Step S16: Optimizing the mesh quality of the adaptive triangular mesh model to obtain a refined triangular mesh model.

[0059] The embodiment of the present invention optimizes the mesh quality of the adaptive triangular mesh model. The optimization process includes but is not limited to checking the uniformity, angle, size and shape of the mesh to ensure the stability and accuracy of the mesh structure. Common optimization methods include eliminating small-angle triangles in the mesh, reducing the proportion of long strip triangles, and adjusting the node positions of the mesh to improve the regularity of the mesh. In addition, the mesh quality is improved by locally refining or merging triangles to ensure that the calculation error of each mesh unit is minimized. Finally, a refined triangular mesh model is obtained.

[0060] The present invention can eliminate the data differences caused by different measuring tools or technologies, unify the data format, and ensure the consistency in the subsequent processing process by acquiring the three-dimensional model data of the part and performing standardization processing. Standardization processing enables part models from different sources to be analyzed and calculated in the same processing environment, thereby improving the versatility and reliability of data processing. Discretization of the part surface based on the standardized three-dimensional model data helps to convert the continuous surface into a series of discrete point sets, which provides accurate discretization data for the subsequent triangular mesh model construction. The discretized data can more accurately describe the local features of the part surface, ensuring that the subsequent tool path generation is more accurate and efficient. The preliminary triangular mesh model is constructed using the discretized data of the part surface, laying the foundation for the subsequent multi-axis CNC tool path generation. The triangular mesh model can accurately represent the geometric shape of the part surface, and is easily compatible with other calculation methods, providing refined processing path data. Discrete curvature calculation is performed on the preliminary three-dimensional mesh model, and the local shape features of the part surface, especially the area with large curvature, can be extracted. This information is crucial for the posture optimization of the tool and the selection of the processing strategy, and helps to ensure that the tool contacts the part surface at an appropriate angle, thereby improving the processing accuracy and surface quality. Adaptive meshing of the preliminary 3D mesh model based on the part surface curvature data can achieve finer meshing in areas with large curvature changes, while using coarser meshes in flatter areas. Adaptive meshing can optimize mesh quality and reduce the waste of computing resources, while providing sufficient detail support in key areas to improve the accuracy and efficiency of tool path generation. Mesh quality optimization of the adaptive triangular mesh model ensures the connectivity and smoothness of the mesh and avoids calculation errors caused by mesh quality issues.

[0061] Preferably, step S2 comprises the following steps:

[0062] Step S21: extracting triangle vertices from the refined triangular mesh model to obtain a triangle vertex coordinate data set;

[0063] Step S22: Calculate the triangle normal vector based on the triangle vertex coordinate data set to obtain initial triangle normal vector data;

[0064] Step S23: normalizing the initial triangle normal vector data to obtain standardized triangle normal vector data;

[0065] Step S24: Smoothing the normalized triangle normal vector data to obtain smoothed triangle normal vector data;

[0066] Step S25: Perform normal vector direction consistency check on the smoothed triangle normal vector data, and mark the model feature area to obtain triangle normal vector data.

[0067] As an embodiment of the present invention, refer to Figure 3 As shown, Figure 1 Detailed step flow diagram of step S2 in the embodiment of the present invention, step S2 includes the following steps:

[0068] Step S21: extracting triangle vertices from the refined triangular mesh model to obtain a triangle vertex coordinate data set;

[0069] The embodiment of the present invention extracts the vertex coordinate data of each triangle from the refined triangular mesh model. All triangles in the mesh model are traversed, and the coordinate values ​​of the three vertices of each triangle are obtained. For each triangle, the three-dimensional coordinates (X, Y, Z) of its vertices are recorded, and these coordinate data are stored in the vertex data set.

[0070] Step S22: Calculate the triangle normal vector based on the triangle vertex coordinate data set to obtain initial triangle normal vector data;

[0071] The embodiment of the present invention calculates the triangle normal vector based on the triangle vertex coordinate data set. For each triangle, the coordinate values ​​of its three vertices are used to calculate the normal vector of the triangle. The calculation process usually adopts the vector cross multiplication method, firstly calculating the vectors of the two sides, and then performing a cross multiplication operation on the two vectors to obtain a normal vector perpendicular to the triangle. By calculating the direction and size of the normal vector, the normal vector data of each triangle is obtained. During the calculation process, in order to ensure the accuracy of the normal vector, the vertex coordinates of each triangle can be accurately processed, and it is ensured that the calculation result meets the geometric constraints. Finally, the initial triangle normal vector data is obtained.

[0072] Step S23: normalizing the initial triangle normal vector data to obtain standardized triangle normal vector data;

[0073] The embodiment of the present invention performs normalization processing on the initial triangle normal vector data. The modulus of each normal vector, that is, the length of the vector, is calculated. For the normal vector of each triangle, the length of all normal vectors is unified to 1 by dividing it by its modulus. The normal vectors after standardization will have the same scale, which is helpful for subsequent smoothing and directional consistency verification. During the standardization process, if a zero vector is encountered (for example, the normal vector of a planar triangle is zero), an appropriate processing method (such as skipping or assigning a default value) can be used to avoid calculation errors. Finally, standardized triangle normal vector data is obtained.

[0074] Step S24: Smoothing the normalized triangle normal vector data to obtain smoothed triangle normal vector data;

[0075] The embodiment of the present invention performs smoothing on the normalized triangle normal vector data. For each triangle normal vector, the normal vectors of its neighboring triangles are considered, and the smoothed value of the current normal is calculated by weighted averaging. Generally, the smoothing process combines the current triangle normal vector with the adjacent triangle normal vectors, and adjusts the direction of the current normal according to the similarity of the adjacent triangles. The smoothing algorithm can adopt a simple neighborhood average algorithm or a more complex weighted average method, in which the weight is usually related to the area or angle of the adjacent triangles. The smoothing process can be repeated until the normal vector reaches a certain degree of smoothness within the neighborhood, thereby reducing the normal direction fluctuation caused by mesh irregularity or excessive discreteness. Finally, smoothed triangle normal vector data is obtained.

[0076] Step S25: Perform normal vector direction consistency check on the smoothed triangle normal vector data, and mark the model feature area to obtain triangle normal vector data.

[0077] The embodiment of the present invention performs a directional consistency check on the smoothed normal vector data of adjacent triangles to check whether the direction of the normal vector meets the expected smoothness and continuity requirements. If there is an obvious inconsistency in the direction of the normal vectors of adjacent triangles (for example, the direction difference exceeds a certain threshold), these areas need to be specially processed, such as readjusting the normal vectors or marking them as feature areas. In order to achieve directional consistency check, judgment can be made based on the angle between the normal vectors. When the normal angle of adjacent triangles is less than a certain set allowable value, their normal directions are considered to be consistent, otherwise it is considered that there is an inconsistency. During the inspection process, weights can be assigned to the normal vectors, their values ​​can be adjusted according to the consistency of the normal direction, or areas with inconsistent directions can be directly marked. According to the results of the normal direction consistency check, the feature area of ​​the model is marked. Finally, the triangle normal vector data containing the consistency check results and the feature area mark is obtained.

[0078] The present invention can obtain the precise geometric information of each triangle on the surface of the part by extracting the triangle vertices of the refined triangular mesh model. Ensuring that the coordinates of each triangle vertex are accurate and can effectively represent the surface shape of the part is the prerequisite for generating high-precision tool paths. The triangle normal vector is calculated based on the triangle vertex coordinate data set, and an accurate surface normal vector can be provided for each triangle. These normal vectors are key data for determining the tool cutting angle, posture and surface processing sequence, which can affect the stability and processing effect of the tool movement, and provide the necessary geometric basis for subsequent tool posture optimization and path planning. Standardizing the initial triangle normal vector data can eliminate the size differences in the normal vector data of different triangles, so that all normal vectors have a unified scale. This process improves the accuracy and reliability of subsequent steps, especially when the tool posture is adjusted, the standardized normal vector helps to ensure that the tool can be processed in a consistent direction. Smoothing the standardized triangle normal vector data can eliminate the sudden change in the normal direction and avoid drastic changes or instability in the tool posture. The smoothed normal vector makes the tool path change more smoothly, reduces the vibration, tool wear and processing errors caused by the sharp change of tool posture during the processing, and improves the processing quality and efficiency. The normal vector direction consistency check is performed on the smoothed triangle normal vector data, and the model feature area is marked, which helps to identify the complex areas and key feature areas on the part surface. Through consistency inspection, it can ensure that the tool cuts in at different positions. The angle is consistent to avoid errors or inconsistencies during the processing process. Marking feature areas helps to focus on complex areas in path planning, thereby optimizing processing strategies and improving processing accuracy.

[0079] Preferably, step S3 comprises the following steps:

[0080] Step S31: identifying key feature areas on the surface of the part on the refined triangular mesh model to obtain surface feature data of the part;

[0081] The embodiment of the present invention uses a curvature calculation algorithm (such as Gaussian curvature and mean curvature) to analyze the local curvature value of each vertex in the refined triangular mesh model. During the calculation, for each vertex, the curvature value is calculated using the differential geometry formula based on the rate of change and relative position of the normal vector of the connected neighboring triangles. After the curvature is calculated, the curvature value is compared with the preset threshold, and the vertices with larger curvature are screened out as preliminary markers for high curvature areas. Subsequently, the key feature area is expanded, and the connected areas are clustered by tracing the neighborhood connection relationship of the high curvature points. The clustering method can use a distance-based regional growing method to classify adjacent points and triangles into the same feature area. Finally, the identified feature areas are classified and marked to generate key feature data of the part surface.

[0082] Step S32: acquiring tool parameter data, selecting a tool path generation strategy according to the part surface feature data and the tool parameter data, and obtaining tool path generation strategy selection data;

[0083] The embodiment of the present invention selects a tool path generation strategy based on the key feature data of the part surface in combination with the tool parameter data (such as tool diameter, cutting depth, feed speed and tool shape). The tool parameter file is parsed, and the relevant values ​​are extracted and stored in a structured data format. The part surface feature data is matched with the tool parameters, and the matching rules are based on the complexity of the processing area features (such as high curvature or narrow areas) and the performance limitations of the tool. Taking rule matching as an example, if the feature area contains a large number of high curvature points, a small diameter tool is selected and a local fine cutting strategy is adopted; if the feature area is a smooth large area, a large diameter tool is selected and a parallel cutting strategy is used. After the matching is completed, the tool path generation strategy selection data is generated.

[0084] Step S33: Perform preliminary tool path design using the key feature data of the part surface and the tool path generation strategy selection data.

[0085] The embodiment of the present invention designs a preliminary tool path through a geometric path calculation method based on the key feature data of the part surface and the tool path generation strategy selection data. The triangular mesh area of ​​the part surface is divided into different processing sub-areas, and each sub-area corresponds to a tool path generation strategy. For high curvature areas, a layered cutting path design method is used to offset the area equidistantly along the surface normal direction to generate a multi-layer contour cutting path. For smooth large areas, a parallel cutting path design method is adopted. By calculating the spindle direction, a straight line trajectory parallel to the processing plane is generated. The spacing of the straight line trajectory is set according to the tool diameter and surface roughness requirements. During the path design, the tool path needs to be smoothed, and the discontinuity between paths is eliminated through an interpolation algorithm to ensure the smoothness of the tool path. After the design is completed, the tool path is stored in the form of a serialized point set or vector curve to obtain preliminary tool path data.

[0086] The present invention identifies the key feature areas of the part surface on the refined triangular mesh model, and can effectively extract the complex geometric shapes and functional features on the part surface. This process helps to clearly identify the functional areas of the part, ensuring that these key areas can be accurately processed during the tool path generation process. By identifying the surface feature areas, it can provide an important basis for tool selection and path planning, and improve the processing accuracy and quality. Obtaining tool parameter data and selecting a tool path generation strategy based on the part surface feature data and tool parameter data helps to determine the most suitable tool path generation method. This strategy selection ensures that the tool can complete the task efficiently and stably during the processing process and avoid unnecessary processing errors. By comprehensively considering the geometric features of the part and the performance of the tool, an optimized processing strategy can be formulated, thereby improving processing efficiency and reducing tool wear. Using the key feature data of the part surface and the tool path generation strategy selection data to perform preliminary tool path design, a preliminary tool path that meets the surface features of the part and processing requirements can be generated. This design ensures that the tool path planning can adapt to the surface shape and processing requirements of the part to the greatest extent, avoiding unnecessary deviations during processing.

[0087] Preferably, step S33 includes the following steps:

[0088] Step S331: subdividing the key feature data of the part surface into micro units to obtain subdivided key feature area data;

[0089] After the key feature areas on the surface of the part are identified, the embodiment of the present invention uses a recursive subdivision method to divide these feature areas into tiny units. Based on the geometric properties of each feature area, the area and curvature value of the area are calculated. By setting a specific threshold, the area with a curvature greater than the threshold is further subdivided. The subdivision operation can be performed by gridding to decompose the area into multiple smaller triangular or rectangular units, and the size of each unit is automatically adjusted according to the surface curvature and local geometric complexity. For example, in high curvature areas, the subdivided units will be smaller to ensure the accuracy of path calculation; in flatter areas, the subdivided units are larger. The subdivided data structure is usually stored in the form of a two-dimensional array or grid, containing the geometric information of each tiny unit (such as vertex coordinates and normal vectors) to obtain subdivided key feature area data.

[0090] Step S332: Designing path points according to the subdivided key feature area data and tool path generation strategy to obtain rough tool path point data;

[0091] The embodiment of the present invention evenly arranges the path points in each sub-triangle according to the surface shape of each tiny unit in the subdivided key feature area data, usually using a uniform distance spacing method. For high curvature areas, the point arrangement density can be determined by calculating the rate of change of the normal vector in the area. For example, in areas with large curvature changes, the distance between path points is set smaller to ensure that the path points can cover complex surface geometry. The tool path generation strategy affects the arrangement of path points. For flat areas, path points are arranged in a regular grid, while for curved areas, path points are arranged using contour lines or equidistant projections. During the design process, the path points must be adjusted according to the size and shape of the tool to ensure that the tool can pass through each path point smoothly. The final rough tool path path point data is stored in the form of three-dimensional coordinates.

[0092] Step S333: Connecting the path point data of the roughing tool path based on the preset processing requirements to obtain the roughing tool path segment data;

[0093] The embodiment of the present invention is based on coarse path point data, and connects the path points one by one in order by calculating the shortest distance between adjacent path points. When connecting, taking into account the directionality of processing and the movement of the tool, an interpolation algorithm, such as linear interpolation or spline interpolation, is used to make a smooth transition between path segments without abrupt changes in direction. For more complex areas, Bezier curves or NURBS (non-uniform rational B-splines) are used to connect the path segments. This method can effectively maintain the smoothness of the curve and reduce tool jitter. In the process of connecting the path segments, ensure that the angle of the tool is smooth each time it turns, and avoid processing vibration or tool damage caused by excessive angle changes. Each path segment is composed of a number of path points, and finally forms coarse tool path segment data.

[0094] Step S334: optimizing the path segment connection sequence according to the rough tool path segment data to obtain optimized tool path segment data;

[0095] The embodiment of the present invention analyzes the relative positions of the starting point and the end point of each path segment, as well as the connection cost of adjacent path segments based on the rough tool path segment data. The connection cost is usually calculated based on the distance between the path segments, the angle change and the processing time. For example, when the end point of a path segment is close to the starting point of the next path segment, the connection cost is low; if the interval between the path segments is large or the angle changes dramatically, the connection cost is high. In order to reduce the idle time of the tool and the repeatability of the path, a greedy algorithm or a genetic algorithm is used to optimize the arrangement order of the path segments. The order of the path segments is adjusted through multiple iterations so that the processing time of the entire path is the shortest and the tool movement on the path is the smoothest. After the optimization is completed, the obtained path segments are arranged in an optimized order to form optimized tool path segment data.

[0096] Step S335: integrating the optimized tool path segment data to obtain preliminary tool path data.

[0097] The path segment integration of the embodiment of the present invention is achieved by connecting the optimized path segments into a complete preliminary tool path. The integration process first splices each path segment in sequence according to the connection order of the path segments. A smooth transition is made between each two path segments through an interpolation method to ensure that there is no sudden change in direction when the tool moves between paths. During the path segment integration process, if there are unnecessary duplicate or redundant parts between the paths, they are removed and merged to ensure the simplicity of the path. During integration, the path must also be corrected according to the actual size and shape of the tool to ensure that the tool can cover the entire machining surface and avoid missed or overcutting of the tool. Finally, preliminary tool path data is obtained.

[0098] The present invention can describe the geometric features of the part more finely, especially in the complex or delicate processing area, by subdividing the key feature data of the part surface into small units. This subdivision helps to improve the processing accuracy and ensure that the tool path can accurately match the complex geometric shape of the part surface. At the same time, the subdivided key feature area provides a more accurate processing area, laying the foundation for the subsequent tool path path point design. The path point design is carried out according to the subdivided key feature area data and the tool path generation strategy, which can ensure that the generation of the tool path is accurately matched with the feature area of ​​the part surface. The path point design avoids the excessive looseness or over-density of the path by considering the working principle and processing requirements of the tool, and improves the rationality and processing efficiency of the tool path. By optimizing the layout of the path points, the invalid time of the tool movement during the processing process can be better reduced, thereby improving the processing efficiency. The path points of the rough tool path path point data are connected based on the preset processing requirements, which can ensure that the tool can reasonably complete the processing task according to the specific processing requirements. The connection of the path points makes the tool path more continuous and smooth, avoids repeated movement or excessive path correction of the tool, improves the processing efficiency, and reduces the processing time. By optimizing the connection sequence of the rough tool path segment data, the optimization degree of the tool path can be further improved, and the repeated movement of the tool and redundant paths can be reduced. Optimizing the connection sequence of the path segments helps to reduce unnecessary movement during machine operation, improve the efficiency of the machining process and reduce mechanical wear. Path segment sequence optimization ensures smooth operation of the tool and avoids potential machining problems. The optimized tool path segment data is integrated into the path segments to obtain preliminary tool path data, which provides a clear path framework for subsequent tool path smoothing optimization and posture adjustment.

[0099] Preferably, step S4 comprises the following steps:

[0100] Step S41: performing correlation analysis on the normal vector data of the triangular mesh and the preliminary tool path data to obtain path point-normal vector correlation data;

[0101] When the embodiment of the present invention performs correlation analysis on the normal vector data of the triangular mesh and the preliminary tool path data, the path point coordinates in the preliminary tool path data and the normal vector direction data in the triangular mesh normal vector data are extracted. By matching the spatial position of the path point with the spatial position of the triangular mesh vertex, the point-to-plane vertical projection method is used to determine the triangular facet where the path point is located, and the normal vector of the facet is obtained. In the calculation of each path point, the facet with the smallest vertical distance is preferentially selected as the corresponding facet of the path point to avoid matching errors. For areas where the path points are densely populated, the comprehensive normal vector in the neighborhood is calculated by the weighted average method of the normal vector direction to reduce discrete errors. The data matching results of the path point and the normal vector are stored in the form of a combination of the path point coordinates and the normal vector to form path point-normal vector correlation data.

[0102] Step S42: Acquire CNC machine tool parameter data, set the tool posture range based on the tool parameter data and the CNC machine tool parameter data, and obtain tool posture adjustment constraint condition data;

[0103] After the embodiment of the present invention obtains the CNC machine tool parameter data and the tool parameter data, the tool posture adjustment constraint conditions are set according to the actual processing requirements. The machine tool parameter data include the angle limit of the rotating axis, the travel range of the linear axis and its dynamic characteristics (such as the maximum acceleration and speed), and the tool parameter data include the tool radius, length and blade angle. Based on these data, a constraint model is established, for example, the Lagrange multiplier method is used to constrain the boundary conditions of the tool motion space. The upper and lower limits are set for the rotation angle of the tool, for example, the tool spindle angle range is defined as -90° to 90°, and the inclination angle change rate is set to avoid violent movement. In addition, the situation where the tool length exceeds the working range of the machine tool is judged, the processing path and the tool posture range are dynamically adjusted, and finally the tool posture adjustment constraint condition data is generated.

[0104] Step S43: performing preliminary tool posture calculation according to the path point-normal vector association data and tool posture adjustment constraint condition data to obtain preliminary tool posture data;

[0105] The embodiment of the present invention calculates preliminary tool posture data based on the path point-normal vector association data and the tool posture adjustment constraints. Using the geometric calculation method, the normal vector of the path point is used as the tool axial reference, and the initial value of the tool posture is determined in combination with the machine tool motion parameters. The Euler angle or quaternion is used to represent the tool posture angle, and the inverse kinematics method is used to solve the tool posture parameters so that it meets the machining surface characteristics and constraints. In specific operations, the normal vector of the path point is used as the direction constraint of the tool spindle, and the contact point between the tool and the workpiece is adjusted in combination with the machining curvature and the tool length. During the calculation, the interpolation method is used to generate a continuous tool posture trajectory for discrete path points to ensure smooth tool motion between path points, and finally form preliminary tool posture data.

[0106] Step S44: Smoothing the preliminary tool posture data to obtain optimized tool posture data.

[0107] The smoothing process of the preliminary tool posture data in the embodiment of the present invention is intended to eliminate discontinuities and mutations between postures. The tool posture trajectory is interpolated and curve-fitted, and the smoothing process uses spline curves or low-pass filtering technology, such as using the B-spline method to fit discrete posture points into a continuous curve. During processing, the angle change rate of each segment of the tool posture is limited to a certain range, such as controlling the angle change per second to not exceed 5°, to avoid vibration or mechanical overload during processing. In the smoothing algorithm, the complexity of the machined surface must also be considered, and the sensitivity of the tool posture adjustment must be appropriately increased for complex areas. After smoothing, the generated optimized tool posture data has continuity and stability within the entire path range, which meets the requirements of machining path planning.

[0108] The present invention can ensure the precise matching of the tool path and the surface features of the part by performing correlation analysis on the normal vector data of the triangular mesh and the preliminary tool path data. The association between the path point and the normal vector not only helps to determine the cutting direction of the tool, but also can accurately adjust the posture of the tool, thereby improving the accuracy of the tool processing surface. This step ensures that the tool path is consistent with the surface of the part by optimizing the selection of the path point and the matching of the normal vector, thereby avoiding unnecessary processing errors. The numerical control machine tool parameter data is obtained, and the tool posture range is set based on the tool parameter data and the numerical control machine tool parameter data, which provides key constraints for the tool posture adjustment during the processing process. By accurately setting the machine tool and tool parameters, it is possible to ensure that the movement of the tool is adapted to the working environment of the machine tool, prevent processing problems caused by improper tool posture, and ensure the smoothness and safety of the processing process. According to the path point-normal vector association data and the tool posture adjustment constraint condition data, a preliminary tool posture calculation is performed, and the correct initial posture data is provided for the tool during the actual processing process. This step ensures the initial rationality of the tool posture, avoids uncoordinated contact between the tool and the part surface, ensures machining accuracy, and provides basic data for subsequent tool posture optimization. Smoothing the preliminary tool posture data helps reduce drastic changes or discontinuities caused by tool posture adjustments during machining. Through smoothing, the tool's motion trajectory is optimized, the adverse effects of sudden posture changes on machining results are avoided, and the stability of the machining process and tool life are improved. The optimized tool posture helps ensure machining accuracy and reduce errors caused by unstable posture.

[0109] Preferably, step S41 includes the following steps:

[0110] Step S411: extracting the three-dimensional spatial coordinates of the path points from the preliminary tool path data to obtain the three-dimensional spatial coordinate data of the path points;

[0111] For the preliminary tool path data, the embodiment of the present invention first extracts the three-dimensional spatial coordinates of the path points. In the specific operation, the coordinate information of each path point in the preliminary tool path data is deconstructed into a separate coordinate value, divided into three components of X, Y, and Z, and stored in the path point coordinate data set. The operation is completed using numerical analysis technology or directly reading the geometric data field of the tool path file. For example, the point data of the G code is located in the tool path data generated by the NC code or CAD / CAM, the corresponding coordinate value is read for each path point instruction, and stored as a set of ordered three-dimensional vector sets in the path order to form the three-dimensional spatial coordinate data of the path point.

[0112] Step S412: performing triangular mesh surface mapping based on the three-dimensional space coordinate data of the path point to obtain path point-mesh surface mapping data;

[0113] The embodiment of the present invention constructs a KD tree acceleration structure to represent the spatial distribution of a triangular mesh based on the three-dimensional spatial coordinate data of the path point. The three-dimensional coordinates of each path point are input, and the triangle patch where the path point is located is quickly located through the nearest neighbor search algorithm of the KD tree, and the mapping relationship between the path point and the mesh patch is recorded. If the path point is not directly located in the patch, the distance between it and the adjacent patch is calculated to select the nearest patch as the mapping target. For the case where the path point falls on the patch boundary, the angle between the path point and the patch normal vector and the weight relationship to the vertex are calculated to finally determine the unique patch mapping result, and the path point and patch information are stored as path point-mesh patch mapping data.

[0114] Step S413: extracting normal vectors of each path point from the triangular mesh normal vector data according to the path point-mesh patch mapping data to obtain path point-normal vector mapping data;

[0115] The embodiment of the present invention utilizes the path point-mesh patch mapping data to extract the corresponding path point normal vector from the triangular mesh normal vector data. For the case where the path point falls completely within a single patch, the normal vector of the patch is directly used as the normal vector of the path point. For the case where the path point is located at the boundaries of multiple patches or their peripheries, the path point normal vector is calculated by interpolation of the patch vertex normal vectors. The specific calculation method is to perform a weighted average of the vertex normal vectors according to the centroid weights from the path point to the three vertices of the patch to obtain the normal vector of the path point. After the extraction is completed, the path point and the normal vector are stored in correspondence as the path point-normal vector mapping data.

[0116] Step S414: verify the path point-normal vector mapping data, and integrate the path point three-dimensional space coordinate data, the triangle mesh normal vector data and the verification result to obtain the path point-normal vector association data.

[0117] The embodiment of the present invention verifies the path point-normal vector mapping data by calculating the angle between the path point normal vector and the corresponding mesh face normal vector to ensure that the angle value is less than a specified threshold (such as 10 degrees) to verify the accuracy of the data. For path points whose angles are out of range, the normal vector is corrected by recalculating its normal vector interpolation value or adjusting the path point mapping face. After the verification is completed, the verification result is integrated with the three-dimensional coordinate data of the path point and the normal vector data of the triangular mesh into complete path point-normal vector associated data, which is stored as a structured data file. In the final result, each path point corresponds to a unique normal vector and its associated three-dimensional coordinates.

[0118] The present invention can accurately convert the tool path into coordinate data in three-dimensional space by extracting the three-dimensional spatial coordinates of the path points from the preliminary tool path data. This step provides basic data for subsequent tool path analysis and optimization, ensures that the positional relationship between the tool path and the part surface is accurate, and avoids position deviation or error in the CNC machining process. Based on the three-dimensional spatial coordinate data of the path points, triangular mesh facet mapping is performed to correspond the tool path points to the facets of the triangular mesh model. Through this mapping process, the tool path can be better combined with the part surface, so that the design of the tool path is closely related to the geometric features of the part, thereby improving the accuracy in the machining process and the adaptability of the tool to the surface shape. According to the path point-mesh facet mapping data, the path point normal vector is extracted from the triangular mesh normal vector data, and accurate cutting direction information is provided for each path point. The extraction of the normal vector ensures that the tool posture is consistent with the surface normal, thereby avoiding uneven cutting or tool wear problems caused by incorrect posture during the tool cutting process, and improving machining accuracy and tool efficiency. Verifying the path point-normal vector mapping data and integrating the path point 3D space coordinate data, triangular mesh normal vector data and verification results can verify the precise match between the tool path and the part surface. By verifying and integrating data, potential processing problems can be discovered, such as inconsistency between the path and the surface or incorrect normal vector direction, and timely adjustments can be made to ensure the optimization of the tool path and the smooth progress of the processing process.

[0119] Preferably, step S43 includes the following steps:

[0120] Step S431: setting the initial direction of the tool posture based on the path point-normal vector association data to obtain preliminary tool posture direction data;

[0121] The embodiment of the present invention analyzes the normal vector of each path point based on the path point-normal vector association data, and sets the initial direction of the tool posture based on the normal vector. In the specific operation, the direction of the normal vector is set as the direction of the tool axis, and the feed direction of the tool is set as the direction of the line between the path points. Assume that the normal vector of the path point is [n x ,n y ,n z ], initialize the tool axis direction vector to be parallel to the normal vector [t x ,t y ,t z ]=[n x ,n y ,n z]. When machining complex surfaces, a local coordinate system is established and the tool angle is adjusted in the local coordinate system to avoid excessive angle offset between path points. Finally, the initial direction data is stored in the form of a three-dimensional vector to form preliminary tool posture direction data.

[0122] Step S432: performing tool posture direction constraint adjustment on the preliminary tool posture direction data according to the tool posture adjustment constraint condition data to obtain preliminary tool posture constraint data;

[0123] The embodiment of the present invention adjusts the constraint range of the preliminary tool attitude direction data according to the tool attitude adjustment constraint condition data. By parsing the CNC machine tool parameters, the motion range of the tool is obtained, including the angle limit of the rotation axis, the motion range of the linear axis and the spatial limit of the processing area. For the tool attitude direction data of each path point, the angle between the tool axis direction and the normal vector is calculated to ensure that the angle is within the actual motion range of the tool. Assuming that the angle exceeds the limit range (such as ±45°), the attitude direction is recalculated by adjusting the rotation angle of the tool relative to the normal vector. For the direction change between the path points, it is corrected by adding intermediate interpolation points or adjusting the angle distribution of the path segments. Finally, the adjusted data is saved as preliminary tool attitude constraint data.

[0124] Step S433: performing adjacent path point posture interpolation calculation on the preliminary tool posture direction data based on the preliminary tool posture constraint data to obtain preliminary tool posture interpolation data;

[0125] The embodiment of the present invention performs interpolation calculation on the tool attitude direction between adjacent path points based on preliminary tool attitude constraint data. First, the tool attitude direction of each path point is represented as a quaternion to ensure the smoothness and accuracy of the direction interpolation. The attitude interpolation value between adjacent path points is calculated using the spherical linear interpolation (SLERP) algorithm. The interpolation calculation result is stored as a continuous attitude direction data set to form preliminary tool attitude interpolation data.

[0126] Step S434: Conflict identification is performed on the preliminary tool posture interpolation data, and correction is performed based on the conflict identification result to obtain preliminary tool posture data.

[0127] The embodiment of the present invention performs conflict identification on the preliminary tool posture interpolation data by detecting whether the tool posture exceeds the motion limit between the path segments, including excessive angle change, collision between the tool and the workpiece, or the tool exceeds the motion range of the CNC machine tool. For the identified conflicting path segments, corrections are made by recalculating the interpolation points or adjusting the posture direction. The specific method includes adding intermediate posture direction points to the conflict points to reduce the posture change angle; or adjusting the angle between the tool and the normal vector in the conflict segment to ensure that it is within the tool motion range. The corrected data is verified by simulation to check whether the conflict is completely eliminated. Finally, the corrected data is saved as preliminary tool posture data.

[0128] The present invention sets the initial direction of tool posture based on path point-normal vector association data, which helps to determine the initial posture direction of the tool for each path point. By accurately setting the tool posture direction, it is ensured that the tool can maintain the correct cutting direction with the normal of the part surface during the processing, thereby improving the processing accuracy and reducing the processing deviation caused by posture errors. According to the tool posture adjustment constraint condition data, the preliminary tool posture direction data is adjusted to ensure that the tool posture meets the various constraint requirements during the processing, such as the maximum rotation angle or interference limit of the tool. This step avoids inappropriate direction adjustment of the tool during the processing by reasonably constraining the tool posture, and ensures the avoidance of interference between the tool and the workpiece during the processing, thereby improving the safety and reliability of the processing. Based on the preliminary tool posture constraint data, the preliminary tool posture direction data is interpolated for adjacent path point postures, which can smoothly transition the tool posture and avoid abrupt posture changes between path points. Through interpolation calculation, the continuity of the tool posture between the path points is ensured, thereby reducing the cutting instability caused by posture jumps or excessive changes during the processing, and improving the surface quality of the processing and the service life of the tool. Conflict identification of preliminary tool posture interpolation data can effectively identify and avoid interference or collision between tool posture and processing environment. By correcting the conflicting tool posture, it is ensured that the tool path will not collide with other parts or equipment during the processing, avoiding the risk of damaging the tool, equipment or affecting the processing quality, thereby ensuring the safety and accuracy of the processing process.

[0129] Preferably, step S5 comprises the following steps:

[0130] Step S51: performing path posture matching on the preliminary tool path data and the optimized tool posture data to obtain path point-posture matching data;

[0131] When the embodiment of the present invention matches the preliminary tool path data with the optimized tool posture data, the corresponding relationship between the path point and the posture data is established to ensure that the tool posture of each path point is consistent with the three-dimensional coordinates of the path point. First, the spatial position coordinate information of each path point in the preliminary tool path data is parsed, and the corresponding tool posture parameters, including the tool axis direction and rotation angle, are extracted from the optimized tool posture data. According to the index number of the path point, the posture data is assigned to the corresponding path point to generate a path point-posture matching data set. During the matching process, a data structure is used to store the three-dimensional coordinates of the path point and the corresponding tool posture parameters, and all matching relationships are verified to ensure that the posture direction is consistent with the processing requirements of the path point. Finally, the path point-posture matching data is obtained.

[0132] Step S52: constructing a three-dimensional virtual model of the processing environment using the three-dimensional model data of the parts, the parameter data of the tool and the parameter data of the CNC machine tool to obtain a three-dimensional virtual model of the processing environment;

[0133] The embodiment of the present invention utilizes part three-dimensional model data, tool parameter data and CNC machine tool parameter data to construct a three-dimensional virtual model of the processing environment. First, the part three-dimensional model data is loaded, and a visualization model of the part is generated through a three-dimensional geometric modeling tool (such as OpenGL or Unity3D). Secondly, a three-dimensional model of the tool is established based on the tool parameter data. Combined with the CNC machine tool parameter data, a geometric model of the CNC machine tool is generated and motion restrictions are set. The part model, tool model and machine tool model are aligned, and a unified coordinate system is established with the processing reference of the part model as the origin. Finally, the three-dimensional virtual model of the processing environment is output through the three-dimensional modeling platform.

[0134] Step S53: Based on the path point-posture matching data, a tool motion collision simulation is performed using a three-dimensional virtual model of the machining environment to obtain tool collision detection data;

[0135] The embodiment of the present invention performs collision simulation detection on tool motion based on path point-posture matching data and in combination with a three-dimensional virtual model of a processing environment. First, the path point-posture matching data is loaded, the path points and tool postures are inserted into a virtual processing environment, and the motion trajectory of the tool between the path points is simulated in sequence. Through a collision detection algorithm, such as a detection method based on a bounding volume hierarchy (BVH), it is determined in real time whether interference occurs between the tool and the surface of the part, the fixture, or the machine tool structure. The judgment criterion for collision detection is to detect whether the shortest distance between the two geometric bodies is less than a preset safety clearance value. If it is less than the safety value, a collision is determined to have occurred and the collision position and path point index are recorded. The output tool collision detection data includes the path point coordinates, posture parameters, and collision type information where the collision occurs.

[0136] Step S54: marking and extracting collision path points according to the tool collision detection data to obtain tool collision path point data;

[0137] The embodiment of the present invention marks and extracts the detected collision path points based on the tool collision detection data. The extraction operation locates the position of the path point where the collision occurs by parsing the path point index and the corresponding three-dimensional coordinates recorded in the collision detection data. During the marking process, the collision path points are distinguished from the normal path points by adding an additional flag field to the original path point data set. For each collision path point, the deviation angle between its normal direction and the tool posture and the collision type (such as direct collision between the tool and the workpiece or interference with the fixture) are further recorded. The marked path point data is stored as a separate data file to obtain the tool collision path point data.

[0138] Step S55: using the tool collision path point data to adjust the path point position of the path point-posture matching data, and optimizing the tool posture to obtain collision optimized tool path data.

[0139] The embodiment of the present invention uses the collision path point data to adjust and optimize the path point-posture matching data. First, for the path points where the collision occurs, the path point spacing is adjusted or the position of the path point is offset by recalculating the position coordinates of the path points to avoid collision. For example, when the path point is too close to the surface of the part, the coordinate value of the path point is adjusted by increasing the distance between the tool and the part. Secondly, for the adjusted path points, the corresponding tool posture parameters are recalculated to ensure that the angle between the tool axis direction and the normal vector meets the processing requirements, and the tool rotation angle is optimized to avoid new conflicts. The adjusted and optimized path points and posture matching data are finally stored as collision optimized tool path data.

[0140] The present invention matches the preliminary tool path data with the optimized tool posture data, effectively combines the tool path and the tool posture, and ensures that each path point of the tool during the processing can be cut in the best posture. Through the matching of the path posture, the contact direction and angle between the tool and the part surface are ensured to be correct, the deviation in the processing is reduced, and the processing accuracy and efficiency are improved. The three-dimensional model data of the part, the tool parameter data and the CNC machine tool parameter data are used to construct a three-dimensional virtual model of the processing environment, which helps to accurately simulate the entire processing process in a virtual environment. This step can intuitively display the tool movement, workpiece state and working state of the CNC machine tool during the processing process, provide a reliable three-dimensional virtual scene for subsequent collision detection and optimization, and ensure the safety of processing. Based on the path point-posture matching data, and using the three-dimensional virtual model of the processing environment to perform tool movement collision simulation, the collision problem between the tool and other parts or workpieces during the processing process is effectively identified. Through real-time collision detection, damage or errors caused by interference during the processing process can be avoided, ensuring that a safe distance is maintained between the tool and the equipment, and improving the safety and quality of processing. By marking and extracting collision path points based on tool collision detection data, the path points where collisions occur can be accurately identified, providing key data support for further path optimization. By marking collision path points, potential risk areas in the machining process can be identified and optimized in a targeted manner to avoid potential interference of the tool at these path points. The tool collision path point data is used to adjust the path point position of the path point-posture matching data and optimize the tool posture, thereby eliminating the risk of collision and optimizing the tool motion trajectory. This adjustment process ensures a smooth and interference-free tool path, while optimizing the tool posture, improving machining efficiency and accuracy, and reducing contact problems between the tool and the workpiece, thereby improving the overall quality and safety of machining.

[0141] Preferably, step S6 comprises the following steps:

[0142] Step S61: performing path point smoothing processing on the collision optimized tool path data to obtain smooth optimized tool path point data;

[0143] When processing collision-optimized tool path data, path point smoothing is a key step in reducing discontinuities or sudden changes between path points in an embodiment of the present invention. First, the three-dimensional spatial coordinates of each path point and its connection relationship with the front and rear points are extracted from the path point set. In order to perform smoothing, common smoothing algorithms, such as Bezier curve smoothing or spline interpolation algorithms, are used to gradually transition the drastic changes between path points to a smooth curve. Through smoothing, the sharp changes in angles and irregular fluctuations between path points are reduced, thereby optimizing the smoothness of the tool path. During the processing, it is necessary to maintain a reasonable interval between path points based on the motion characteristics of the CNC machine tool to ensure that the movement of the tool does not experience excessive acceleration or deceleration. Finally, the smoothed optimized tool path point data is output.

[0144] Step S62: performing tool posture smoothing processing on the smooth optimized tool path path point data to obtain smooth optimized tool posture data;

[0145] The embodiment of the present invention performs tool posture smoothing processing on the smooth optimized tool path point data, with the purpose of ensuring that the tool moves in a smooth posture during the path movement process, avoiding excessive posture changes that affect the processing quality. First, the tool posture data corresponding to each path point is extracted from the smooth optimized tool path path point data, including the tool angle and direction. Next, by applying the Kalman filter algorithm or the Lagrange interpolation method to the tool posture data, the tool posture of each path point is optimized, so that the tool posture adjustment between adjacent path points is smoother and more gradual, thereby reducing the tool's sharp turn or position change. When performing posture smoothing, ensure that the tool posture change range is within the predetermined constraints to avoid excessive deviation of the posture from the original plan. Finally, the smooth optimized tool posture data is obtained to ensure that the tool runs along the path with a stable posture.

[0146] Step S63: performing consistency check between the path point and the tool posture data of the smoothed optimized tool posture data to obtain the checked path point-posture data;

[0147] The consistency check of the path point and the tool posture in the embodiment of the present invention is a key link to ensure that the tool can accurately perform processing according to the position of the path point. First, the three-dimensional coordinates of each path point and the corresponding tool posture data are obtained through the path point-posture data. The normal direction of each path point is compared with the direction of the tool posture using geometric relationships to ensure that the tool posture is consistent with the normal direction of the part surface. During the consistency check process, if the tool posture of the path point deviates too much, or the tool posture is opposite to the normal of the part processing surface at some path points, adjustment is required. Through geometric transformation calculation, the inconsistent tool posture is adjusted to ensure that the posture of each path point is consistent with the actual processing requirements, and finally the verified path point-posture data is obtained.

[0148] Step S64: generating a tool path code according to the verified path point-posture data to obtain a tool path code;

[0149] After completing the consistency check between the path point and the tool posture, the embodiment of the present invention generates the tool path code required by the CNC machine tool based on the verified path point-posture data. The tool path code is usually expressed in G code or M code CNC programming language. According to the standard CNC programming language rules, the three-dimensional coordinates of each path point and the corresponding tool posture are output through programming commands. First, for each path point, a corresponding G code instruction is generated to instruct the machine tool control system to move to a specific coordinate position in space. At the same time, according to the verified tool posture data, instructions for adjusting the tool angle and direction are added. The generation of the tool path code must not only consider the accuracy of the path, but also ensure that the tool posture is compatible with the control logic of the CNC machine tool. In the generated G code, each line corresponds to the movement operation of a tool, and these instructions control the tool to move precisely along the optimized path. Finally, the tool path code is obtained.

[0150] Step S65: Use the three-dimensional virtual model of the machining environment to simulate the tool path code and perform executable and safety verification. If the verification fails, return to step S62. If the verification passes, the final optimized tool path data is obtained.

[0151] After generating the tool path code, the embodiment of the present invention uses the three-dimensional virtual model of the machining environment to simulate the tool path code to verify its executability and safety. First, the generated tool path code is input into the virtual numerical control system, and the tool motion is simulated by the virtual machining software. At this time, combined with the three-dimensional virtual model of the machining environment, the motion trajectory of the tool during the machining process is monitored in real time to check whether there is interference or collision between the tool and the parts, fixtures, and machine tools. A special collision detection algorithm is used to simulate the interaction between the tool motion and the environment at each path point, and the detection results are output. If a tool collision occurs during the simulation or the path does not meet the safety requirements, an error message will be fed back, and the process will return to step S62 according to the problem to perform tool posture smoothing or path adjustment, and regenerate the optimized path data. If the verification is passed, the safety and executability of the path are ensured, and the final optimized tool path data is finally obtained.

[0152] The present invention performs path point smoothing on the collision optimized tool path data, which helps to eliminate the sudden change or uneven turning point in the path data and ensures the smooth transition of the tool during the processing. This step avoids excessive vibration or unstable movement of the tool when the path changes by optimizing the continuity of the path, thereby improving the accuracy, stability and efficiency of the processing process. The tool posture smoothing is performed on the smooth optimized tool path path point data to further optimize the tool posture change on the entire path. This step ensures that the tool works in a reasonable and stable posture on the entire processing path, avoids the processing error or instability caused by too drastic posture changes, thereby improving the processing accuracy and tool life. The path point and tool posture consistency check is performed on the smooth optimized tool posture data to ensure that the posture of the tool at each path point is highly consistent with the processing requirements. This check process verifies the matching of the tool path and the tool posture, ensures the accuracy and stability during the processing, avoids unnecessary posture adjustment or error, and ensures the processing quality. The tool path code is generated according to the path point-posture data after the check, and the optimized tool path and tool posture information are converted into a code that can be recognized by the CNC machine tool. This process converts all optimized path data into specific processing instructions to ensure that the CNC machine tool can correctly and accurately execute the path instructions, thereby efficiently completing the processing task. Using the three-dimensional virtual model of the processing environment to simulate the tool path code and verify the executability and safety can effectively avoid collisions or interference between the tool and the workpiece or machine tool parts. The simulation and verification in the virtual model can detect potential problems before actual processing, and avoid safety hazards during processing by adjusting the tool path code, ensuring the safety and effectiveness of the processing process.

[0153] Therefore, no matter from which point of view, the embodiments should be regarded as illustrative and non-restrictive, and the scope of the present invention is not limited by the above description, so it is intended to include all changes within the meaning and scope of the equivalent elements of the application documents in the present invention.

[0154] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features invented herein.

Claims

1. A multi-axis CNC machining tool path generation method based on a part model, characterized in that: The following steps are involved: Step S1: Obtaining three-dimensional model data of parts; Construct a triangular mesh model based on the three-dimensional model data of the part, and perform adaptive meshing on the triangular mesh model to generate a refined triangular mesh model; Step S2: Calculate the normal vector of each triangle based on the refined triangular mesh model to obtain the normal vector data of the triangular mesh; Step S3: Perform preliminary tool path design based on the refined triangular mesh model to obtain preliminary tool path data; Step S4: optimizing the tool posture of the preliminary tool path data using the normal vector data of the triangular mesh to obtain optimized tool posture data; Step S5: performing collision detection based on the preliminary tool path data and the optimized tool posture data, and optimizing and adjusting the preliminary tool path data based on the collision detection result to obtain collision optimized tool path data; Step S6: Smoothly optimize the collision optimized tool path data and convert the tool path code to obtain the final optimized tool path data.

2. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 1, characterized in that: Step S1 includes the following steps: Step S11: acquiring the three-dimensional model data of the part, and performing standardization processing on the three-dimensional model data of the part to obtain standardized three-dimensional model data; Step S12: discretizing the surface of the part according to the standardized three-dimensional model data to obtain discretized data of the surface of the part; Step S13: constructing a triangular mesh model using the discretized data of the part surface to obtain a preliminary triangular mesh model; Step S14: performing discrete curvature calculation on the preliminary three-dimensional mesh model to obtain part surface curvature data; Step S15: Adaptively meshing the preliminary three-dimensional mesh model based on the part surface curvature data to obtain an adaptive triangular mesh model; Step S16: Optimizing the mesh quality of the adaptive triangular mesh model to obtain a refined triangular mesh model.

3. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 1, characterized in that: Step S2 includes the following steps: Step S21: extracting triangle vertices from the refined triangular mesh model to obtain a triangle vertex coordinate data set; Step S22: Calculate the triangle normal vector based on the triangle vertex coordinate data set to obtain initial triangle normal vector data; Step S23: normalizing the initial triangle normal vector data to obtain standardized triangle normal vector data; Step S24: Smoothing the normalized triangle normal vector data to obtain smoothed triangle normal vector data; Step S25: Perform normal vector direction consistency check on the smoothed triangle normal vector data, and mark the model feature area to obtain triangle normal vector data.

4. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 1, characterized in that: Step S3 includes the following steps: Step S31: identifying key feature areas on the surface of the part on the refined triangular mesh model to obtain surface feature data of the part; Step S32: acquiring tool parameter data, selecting a tool path generation strategy according to the part surface feature data and the tool parameter data, and obtaining tool path generation strategy selection data; Step S33: Perform preliminary tool path design using the key feature data of the part surface and the tool path generation strategy selection data to obtain preliminary tool path data.

5. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 4, characterized in that: Step S33 includes the following steps: Step S331: subdividing the key feature data of the part surface into micro units to obtain subdivided key feature area data; Step S332: Designing path points according to the subdivided key feature area data and tool path generation strategy to obtain rough tool path point data; Step S333: Connecting the path point data of the roughing tool path based on the preset processing requirements to obtain the roughing tool path segment data; Step S334: optimizing the path segment connection sequence according to the rough tool path segment data to obtain optimized tool path segment data; Step S335: integrating the optimized tool path segment data to obtain preliminary tool path data.

6. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 1, characterized in that: Step S4 includes the following steps: Step S41: performing correlation analysis on the normal vector data of the triangular mesh and the preliminary tool path data to obtain path point-normal vector correlation data; Step S42: Acquire CNC machine tool parameter data, set the tool posture range based on the tool parameter data and the CNC machine tool parameter data, and obtain tool posture adjustment constraint condition data; Step S43: performing preliminary tool posture calculation according to the path point-normal vector association data and tool posture adjustment constraint condition data to obtain preliminary tool posture data; Step S44: Smoothing the preliminary tool posture data to obtain optimized tool posture data.

7. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 6, characterized in that: Step S41 includes the following steps: Step S411: extracting the three-dimensional spatial coordinates of the path points from the preliminary tool path data to obtain the three-dimensional spatial coordinate data of the path points; Step S412: performing triangular mesh surface mapping based on the three-dimensional space coordinate data of the path point to obtain path point-mesh surface mapping data; Step S413: extracting normal vectors of each path point from the triangular mesh normal vector data according to the path point-mesh patch mapping data to obtain path point-normal vector mapping data; Step S414: verify the path point-normal vector mapping data, and integrate the path point three-dimensional space coordinate data, the triangle mesh normal vector data and the verification result to obtain the path point-normal vector association data.

8. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 6, characterized in that: Step S43 includes the following steps: Step S431: setting the initial direction of the tool posture based on the path point-normal vector association data to obtain preliminary tool posture direction data; Step S432: performing tool posture direction constraint adjustment on the preliminary tool posture direction data according to the tool posture adjustment constraint condition data to obtain preliminary tool posture constraint data; Step S433: performing adjacent path point posture interpolation calculation on the preliminary tool posture direction data based on the preliminary tool posture constraint data to obtain preliminary tool posture interpolation data; Step S434: Conflict identification is performed on the preliminary tool posture interpolation data, and correction is performed based on the conflict identification result to obtain preliminary tool posture data.

9. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 1, characterized in that: Step S5 includes the following steps: Step S51: performing path posture matching on the preliminary tool path data and the optimized tool posture data to obtain path point-posture matching data; Step S52: constructing a three-dimensional virtual model of the processing environment using the three-dimensional model data of the parts, the parameter data of the tool and the parameter data of the CNC machine tool to obtain a three-dimensional virtual model of the processing environment; Step S53: Based on the path point-posture matching data, a tool motion collision simulation is performed using a three-dimensional virtual model of the machining environment to obtain tool collision detection data; Step S54: marking and extracting collision path points according to the tool collision detection data to obtain tool collision path point data; Step S55: using the tool collision path point data to adjust the path point position of the path point-posture matching data, and optimizing the tool posture to obtain collision optimized tool path data.

10. The method for generating tool paths for multi-axis CNC machining based on part models according to claim 1, characterized in that: Step S6 includes the following steps: Step S61: performing path point smoothing processing on the collision optimized tool path data to obtain smooth optimized tool path point data; Step S62: performing tool posture smoothing processing on the smooth optimized tool path path point data to obtain smooth optimized tool posture data; Step S63: performing consistency check between the path point and the tool posture data of the smoothed optimized tool posture data to obtain the checked path point-posture data; Step S64: generating a tool path code according to the verified path point-posture data to obtain a tool path code; Step S65: Use the three-dimensional virtual model of the machining environment to simulate the tool path code and perform executable and safety verification. If the verification fails, return to step S62. If the verification passes, the final optimized tool path data is obtained.

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