Knotter special-shaped part processing method based on feature projection and adaptive ring searching

Abstract

The application discloses a kind of based on feature projection and self-adapting search ring's knotter special-shaped part processing method, it is characterized in that, including the following steps: S1 obtains the three-dimensional model data of knotter special-shaped part, the main tensile direction of model is calculated using principal component analysis method, and combined with the tool positioning strategy based on datum plane+process hole, establish composite machining coordinate system;S2 traverses model topological surface, according to the angle between the normal of each topological surface and the main tensile direction, wall thickness and the relative attitude with tool positioning datum plane, screen out the set of faces to be projected;S3 with the geometric center of part as origin, the main tensile direction is normal to construct self-adapting projection plane, the set of projected faces is projected to the plane to obtain two-dimensional projection edge set, and two-way search ring is carried out using maximum corner priority strategy, generates the two-dimensional closed ring representing different features.

Description

Technical Field

[0001] This invention belongs to the field of agricultural machinery manufacturing and CNC machining technology, specifically relating to a five-axis linkage machining method for irregularly shaped knotter parts based on feature projection and adaptive loop search. Background Technology

[0002] The knotter is the core component of a square bale picker and baler. Its frame, claws, and knotting pliers shaft have complex irregular curved surfaces, spatial angle surfaces, deep holes, and thin-walled structures. The machining accuracy of these parts directly determines the reliability and service life of the knotter.

[0003] Currently, the aforementioned irregularly shaped parts are mainly manufactured using five-axis machining centers. However, existing technologies have the following significant shortcomings: conventional machining equipment cannot achieve multi-angle one-time forming; positioning errors caused by multiple clamping operations are difficult to meet design requirements; even when using five-axis equipment, programming still heavily relies on human experience. For features such as deep cavities and oblique holes, manually programming is inefficient and prone to errors, and improper tool axis vector settings can easily cause tool interference or vibration; the degree of automation is low, and intelligent feature recognition is lacking. Existing CAM software cannot automatically identify complex geometric features (such as spatial oblique surfaces, irregular deep cavities, precision hole systems, etc.) on the irregularly shaped parts of the knotter, and cannot automatically generate optimized five-axis machining paths.

[0004] Therefore, there is an urgent need for an automated, high-precision five-axis linkage machining method that can integrate tooling physical constraints and intelligent feature recognition algorithms to address the characteristics of irregularly shaped knotters. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art and provide a method for processing irregular parts of a knotter based on feature projection and adaptive loop search, so as to solve the problems of low processing efficiency, low degree of programming automation and tool axis interference in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A five-axis linkage machining method for irregularly shaped knotter parts based on feature projection and adaptive loop search includes the following steps:

[0008] S1 acquires the 3D model data of the knotter's irregular part, calculates the principal tensile direction of the model using principal component analysis, and establishes a composite machining coordinate system by combining the tooling positioning strategy based on the datum plane and process holes.

[0009] S2 traverses the model topology surfaces and selects the set of surfaces to be projected based on the angle between the normal of each topology surface and the main stretching direction, the wall thickness, and the relative orientation with the tooling positioning reference surface.

[0010] S3 constructs an adaptive projection plane with the geometric center of the part as the origin and the main stretching direction as the normal. The set of surfaces to be projected is projected onto this plane to obtain a two-dimensional projection edge set. A bidirectional loop search is performed using the maximum rotation angle priority strategy to generate two-dimensional closed loops representing different features.

[0011] S4 generates contour milling paths and hole machining paths based on the properties of the two-dimensional closed loop. For the identified oblique hole features, it automatically calculates the avoidance micro-swing angle to generate interference-free five-axis linkage tool axis vectors and finally outputs five-axis linkage machining code.

[0012] The S5 transmits the machining code to the five-axis machining center, clamps the workpiece once, and completes the machining of all features.

[0013] Furthermore, in step S1, principal component analysis is used to construct a covariance matrix for all surface point cloud data of the part's 3D model:

[0014] ;

[0015] Solve for eigenvalues ​​and eigenvectors, and determine the eigenvector corresponding to the largest eigenvalue as the principal stretching direction; for parts with significant slender features or those stretched from the same contour along a certain direction, use the principal component direction of the overall point cloud as the optimal projection direction.

[0016] in For the first A vector of coordinates of sampling points, Let be the centroid coordinate vector of all sampling points. The total number of sampling points. Transpose a matrix / vector.

[0017] Furthermore, the specific filtering rule in step S2 is: if a certain topological surface satisfies

[0018] ;

[0019] Or wall thickness Less than the preset threshold ,Right now

[0020] ;

[0021] Or the angle between its normal and the tooling positioning reference plane satisfies

[0022] ;

[0023] Then add the topological surface to the set of surfaces to be projected;

[0024] in The threshold for thin-walled components is preset based on material properties and part stiffness. and To preset the angle threshold according to the machining accuracy requirements, The unit vector in the main stretching direction. The unit vector is the normal to the topological surface. To determine the tolerance for verticality, for Normal to the tooling reference plane The included angle.

[0025] Furthermore, the maximum rotation angle priority bidirectional cycle search algorithm in step S3 includes: starting from the starting edge in the deduplicated two-dimensional projected edge set, calculating the clockwise rotation angle between the reverse tangent of the previous edge and the tangent of all candidate adjacent edges at its endpoint, and selecting the candidate edge with the largest rotation angle as the next connecting edge, repeating this process until a closed loop is formed; performing this process along the vector direction of the starting edge and its reverse direction respectively to obtain all internal minimum two-dimensional loops and outer boundary two-dimensional loops.

[0026] Further, generating the five-axis linkage machining code in step S4 includes: back-projecting the two-dimensional closed loop back into three-dimensional space; for the counterclockwise outer boundary loop, generating a three-dimensional contour machining path; for the clockwise inner loop, determining the roundness using a roundness algorithm, and if the roundness... satisfy:

[0027] ;

[0028] The ring is then identified as a precision hole, in which Let be the area of ​​the ring. Let be the circumference of the ring. Set a preset roundness threshold and generate hole machining cycle code;

[0029] For the oblique hole feature, its tool axis vector From the formula

[0030] ;

[0031] Confirmed, among which For the ideal hole axis vector, The avoidance angle is automatically calculated based on the surrounding interference model. The calculation method is as follows: Using the axis as the projection direction along the normal of the interference plane, with a preset step size... Gradually deflect the tool axis until the tool envelope plane is at the nearest interference plane. satisfy:

[0032] ;

[0033] in To set a safe distance.

[0034] Furthermore, in step S1, the method for establishing the composite machining coordinate system is as follows: the positioning surface of the irregular support block on the tooling is taken as the XY plane reference, the axis of the precision positioning pin is taken as the Z-axis direction, the direction of the line connecting the two process holes is taken as the X-axis direction, and the origin is set at the positioning center of the tooling, so that the digital model coordinate system and the physical clamping coordinate system are completely coincident.

[0035] Furthermore, step S5 also includes: when the CNC system executes the code segment corresponding to the thin-walled feature identified in step S2, the system automatically reduces the spindle feed speed to a preset safe feed rate. It also sends a command to the tooling control system to switch the clamping mode to low-pressure floating follow mode, maintaining the clamping force at the preset low-pressure threshold. Within a certain range, to prevent workpiece deformation.

[0036] Furthermore, in step S5, a real-time monitoring and feedback adjustment step is also included during the machining process: the CNC system collects signals in real time through the spindle load sensor and the force sensor on the tooling. When the spindle load exceeds the preset threshold or the clamping force deviates from the set range, the system automatically adjusts the feed rate and clamping force to maintain the stability of the machining process.

[0037] Furthermore, in step S2, the method for identifying thin-walled feature surfaces is as follows: by calculating the minimum local wall thickness of the topological surface. ,like ;

[0038] Then the surface is determined to be a thin-walled feature surface; among them, for aluminum alloy parts =3mm, for steel parts =2mm.

[0039] Furthermore, in step S4, for the identified deep cavity region, the system automatically shortens the tool extension length and adopts climb milling to reduce cutting vibration; for the thin-walled region, the system automatically generates a layered fine milling path, and the cutting depth of each layer is automatically determined according to the material hardness and tool parameters.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] This solution successfully extends the existing thin-walled part projection recognition method to complex knotter irregular parts by introducing process constraint factors and an improved maximum rotation angle priority search algorithm. It realizes automatic recognition of features such as spatial inclined planes, deep cavities, and irregular hole systems without manual intervention, and significantly improves programming efficiency.

[0042] By using a datum plane + process hole single clamping and closed-loop algorithm tooling collaboration strategy, multiple clamping errors were eliminated. The first piece processing verification showed that the spatial position error of the knotter frame can be controlled within 0.02mm.

[0043] This invention automatically calculates the avoidance micro-oscillation angle for oblique hole features, effectively avoiding tool interference and vibration problems, and improving machining quality and efficiency; it deeply integrates an adaptive control strategy based on feature recognition, automatically optimizing cutting parameters when machining easily deformable areas, thus solving the problem of easy deformation in traditional processes from the process level.

[0044] This invention provides a complete technical solution from 3D model input to feature recognition, path planning, five-axis code output, and machine tool adaptive machining, providing a reliable implementation method for the intelligent manufacturing of core agricultural machinery components. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the knotter frame arranged on the base plate of the five-axis clamp, as an example.

[0046] Figure 2 A structural exploded view of the knotter frame arranged on the base plate of the five-axis fixture.

[0047] Figure 3 This is a schematic diagram showing the arrangement of the base plate, positioning posts, and cylindrical pins of a five-axis fixture.

[0048] Figure 4 This is a schematic diagram of the overall structure of the knotter frame.

[0049] Figure 5 This is a schematic diagram of the bottom view of the knotter frame.

[0050] Figure 6 This is a schematic diagram of the projection point structure of the knotter frame.

[0051] Figure 7 This is a schematic diagram illustrating the execution process of the maximum rotation angle priority bidirectional cycle search algorithm.

[0052] Figure 8 Select the schematic diagram for the maximum rotation angle of a single node.

[0053] Figure 9 This is a schematic diagram of the inclined hole feature structure in the frame.

[0054] Figure 10 This is a schematic diagram of the thin-walled structural features in the frame. Detailed Implementation

[0055] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0056] A method for machining irregularly shaped knotter parts based on feature projection and adaptive loop search is proposed. This method combines the deterministic constraints of physical tooling with the adaptive feature extraction of digital algorithms to form an automated closed loop from 3D model to 5-axis machining code. The specific steps include:

[0057] S1 Model Preprocessing and Composite Machining Coordinate System Calibration: A 3D model of the knotter's irregularly shaped components (including the frame, jaws, and knotting clamp shaft) is obtained. First, Principal Component Analysis (PCA) is used to analyze the model's point cloud data, calculating the principal stretching directions and the maximum projection plane. Specifically, a 3×3 covariance matrix is ​​constructed for all surface sampling points of the 3D model.

[0058] ;

[0059] in For the first A vector of coordinates of sampling points, Let be the centroid coordinate vector of all sampling points. The total number of sampling points. Transpose the matrix / vector. For the covariance matrix... Eigenvalue decomposition yields three eigenvalues. and the corresponding feature vectors , , The largest eigenvalue Corresponding feature vector That is, the main stretching direction .

[0060] Secondly, a predefined tooling positioning strategy is used, based on a datum plane and process holes, to establish a composite machining coordinate system. This coordinate system is established as follows: the positioning surface of the irregular support block on the tooling is used as the XY plane datum, the axis of the precision locating pin is used as the Z-axis, and the direction of the line connecting the two process holes is used as the X-axis, with the origin set at the tooling positioning center. This coordinate system not only considers the geometric center of the part but also integrates the physical constraint information of the irregular support block and the precision locating pin on the tooling, ensuring a high degree of consistency between the digital model and the physical clamping state.

[0061] S2 performs dynamic filtering based on feature surfaces constrained by process requirements, traversing all topological surfaces of the 3D model, and calculating the normal vector for each topological surface. With respect to the main tensile direction described in S1 The included angle is used for screening, and the screening is performed in conjunction with preset process constraint factors, which include:

[0062] Wall thickness characteristics are derived by calculating the minimum local wall thickness of the topological surface. ,like ;

[0063] ( The preset thin-wall determination threshold, for example, for aluminum alloy parts. =3mm, for steel parts If the diameter is 2mm, then the surface is determined to be a thin-walled feature surface.

[0064] Spatial attitude, if the normal of a certain topological surface Normal to the tooling positioning datum plane The included angle satisfy:

[0065] ;

[0066] (in , If the angle threshold is preset, it will be forcibly marked as a critical machining surface;

[0067] Normal direction screening selects vectors whose normal direction is perpendicular to the principal tension direction, i.e., those that satisfy the following conditions:

[0068] ;

[0069] ( For example, the preset vertical judgment tolerance. =10 -4 The topological surface of ).

[0070] The above three types of topological surfaces together constitute the set of surfaces to be projected. .

[0071] S3 constructs an adaptive projection plane with the geometric center of the part as the origin and the corrected principal stretching direction in S1 as the normal. The set of surfaces to be projected obtained in S2 All faces in the projection plane are projected along the principal stretching direction to generate a corresponding set of two-dimensional projected edges. And perform deduplication.

[0072] By improving the bidirectional cycle search algorithm, the set of deduplicated two-dimensional projected edges is obtained. In the process, a bidirectional cycle search is performed; during the cycle search, a maximum angle-first strategy is adopted: starting from the initial edge... endpoints Departure, Calculation exist Tangential reversal at the location and find all of them. Candidate edges are defined as endpoints. Calculate them separately. Rotate to the tangent of each candidate edge clockwise angle .choose The corresponding candidate edge is used as the next edge. Repeat this process until a closed loop is formed. By performing this process along the direction of the initial edge vector and its opposite direction, all internal minimum two-dimensional loops and external boundary two-dimensional loops are obtained.

[0073] For each generated closed 2D loop, its clockwise / counterclockwise attribute is calculated. For clockwise loops, a roundness algorithm is used to determine whether they are circular. The formula for calculating roundness is:

[0074] ;

[0075] in Let be the area of ​​the ring. Let be the circumference of the ring. If ( For example, a preset roundness threshold. If the value is 0.9, then the ring is marked as the precision hole machining area.

[0076] S4 generates the corresponding processing path based on the different ring features identified by S3:

[0077] For the counterclockwise outer boundary ring, generate a rough milling path (using a layered cutting strategy, with the depth of cut for each layer automatically determined based on material hardness and tool parameters) and a finish milling path;

[0078] For clockwise rings marked as precision hole systems, generate compound hole machining cycle codes for center drills, drill bits, reamers, or boring tools;

[0079] The system associates the two-dimensional path with its corresponding three-dimensional spatial features, and in particular, automatically calculates the non-interference tool axis vector for the identified oblique hole features.

[0080] The formula for calculating the tool axis vector is:

[0081] ;

[0082] in, This represents the ideal axial direction of the inclined hole. The avoidance micro-oscillation angle is calculated based on the distance to the surrounding interference surfaces. The specific calculation method is as follows: Using the rotation axis as the projection direction along the normal of the interference surface, with a preset step size... (For example Gradually deflect the tool axis and calculate the distance between the tool envelope and the nearest interference surface after deflection. until ;

[0083] ( For example, a preset safe distance =0.5 mm), at which point the deflection angle is .

[0084] Finally, the post-processor converts all paths into five-axis G-code containing precise (X,Y,Z) coordinates and (A,B / C) rotation axis angles.

[0085] S5 transmits the five-axis linkage machining code generated by S4 to the five-axis machining center. The machine tool clamps the workpiece once according to the code and completes the machining of all features.

[0086] During machining, the CNC system monitors the signals from the spindle load sensor and the force sensor on the tooling in real time. The system performs adaptive adjustments when it detects the following conditions:

[0087] When machining the thin-walled feature area identified in S2, the system automatically adjusts the feed rate. Reduce to safe feed rate (For example =800mm / min), and sends a command to the tooling control system to switch the clamping mode to low-pressure floating follow mode, maintaining the clamping force at (For example =50N); when the spindle load exceeds the preset threshold. When the system automatically reduces the feed rate, when the clamping force deviates from the set range, the system automatically adjusts the output pressure of the hydraulic clamping unit. When machining into a deep cavity area, the system automatically shortens the tool extension length and uses climb milling to reduce cutting vibration.

[0088] This embodiment uses the irregularly shaped frame component in the knotter of an agricultural baler as an example to illustrate the implementation process of the present invention in detail.

[0089] refer to Figures 1 to 10 In this embodiment, the knotter frame is a typical irregularly shaped component. This design arranges the frame 1 and frame body 2 on the five-axis fixture base plate 3. Positioning posts 4 are arranged on the five-axis fixture base plate 3. The frame 1 and frame body 2 are securely installed to the positioning posts 4 using hexagonal bolts 5 and spring washers. To prevent axial deflection of the frame 1 at the positioning posts 4, cylindrical pins 6 are arranged at the bottom of the frame 1 and the five-axis fixture base plate 3, achieving a secure integrated structure between the above-mentioned structural components and the five-axis fixture base plate 3. The blank of the frame 1 is arranged on the five-axis fixture base plate 3 in the above manner, and the processing operation is performed according to the following method.

[0090] Step S1: Import the 3D model of the knotter frame and perform principal component analysis (PCA) on the vertices of the model's triangular mesh. Three eigenvalues ​​are calculated. , , and the corresponding eigenvectors, where the largest eigenvalue is... Corresponding feature vector This is the main stretching direction of the model (approximately the Y-axis direction). Simultaneously, based on the preset tooling information (the tooling is positioned using the upper surface of the five-axis fixture base plate 3 as the reference surface and the center points of the positioning columns and cylindrical pins), the CNC system automatically establishes a composite machining coordinate system, aligning the origin of the model coordinate system with the tooling positioning center. In actual operation, the basic surface (the upper surface of the five-axis fixture base plate 3) can be used as the XY plane, with the center line of the bottom of the positioning column 4 as the origin and the center line of the positioning column 4 as the Z-axis.

[0091] Step S2 iterates through all topological surfaces of the frame model. A preset wall thickness threshold is used. =3mm, angle threshold , Vertical judgment tolerance =10 -4 The program calculates the normal to each face. Regarding the normal direction With the main stretching direction satisfy:

[0092] ;

[0093] That is, a nearly vertical surface, or a thin wall surface with a wall thickness of less than 3 mm, or a surface that is perpendicular to the ground. The angle between the reference planes is All key surfaces within the range are added to the set of surfaces to be projected. The assembly includes the inner and outer walls of the frame, the deep cavity sidewalls, and the various mounting ramps.

[0094] Step S3: Projection and adaptive loop search, using the model center point Origin, main stretching direction Construct the projection plane with the normal direction as the reference direction. ,Will All face edges Projected onto a plane The set of two-dimensional projected edges is obtained. And perform deduplication, then, A bidirectional cycle search is performed, starting from the initial edge. endpoints Departure, Calculation exist Tangential reversal at the location and find all of them. Candidate edges are defined as endpoints. Calculate them separately. Rotate to the tangent of each candidate edge clockwise angle .choose The corresponding candidate edge is used as the next edge. Repeat this process until a closed loop is formed.

[0095] This method successfully extracted the counter-clockwise ring representing the outer contour of the frame and the clockwise ring representing the internal deep cavities and hole system. This was achieved using a roundness algorithm (…). = 0.9) Further, rings with a roundness greater than 0.95 are marked as precision hole machining rings.

[0096] Step S4 generates five-axis linkage code. The system automatically plans the path based on the recognition results: for the counterclockwise outer contour ring, it generates rough milling (2mm depth of cut per layer) and finish milling paths; for the clockwise ring marked as a precision hole, it generates a composite hole machining path of center drill > drill bit > reamer.

[0097] For a slanted hole feature on the frame whose normal is at 20° to the coordinate axis (reference) Figure 9 The system extracts its ideal axis. = (0.5, 0.866, 0), by analyzing the surrounding geometric model, it was found that at the current angle, The minimum distance between the standard drill bit and the sidewall is only 0.2mm, posing a risk of interference. The system uses... The tool axis is gradually deflected in increments until it reaches a certain value. At that time, the distance between the tool envelope surface and the nearest interference surface =0.62 mm> = 0.5mm, generating a new interference-free tool axis vector

[0098] ;

[0099] Finally, the post-processor converts all paths into five-axis linkage with precise tool axis vectors. Code.

[0100] Step S5 will generate The code is transferred to the DMG MORI DMU80PduoBLOCK 5-axis machining center. The workpiece is positioned using the datum surface and process holes, with the upper surface of the 5-axis fixture base plate 3 as the datum surface and the center points of the locating pins and cylindrical pins. It is clamped onto the custom fixture in one operation. During machining, when the program reaches the deep cavity milling section, the system automatically shortens the tool extension length according to a preset strategy and uses climb milling. When machining thin walls (see reference...) Figure 10 When the characteristic is met, the system automatically adjusts the feed rate. The speed was reduced from 2000 mm / min to 800 mm / min, and the lateral floating clamping unit on the tooling was instructed to maintain a constant low-pressure clamping (50 N). The entire machining process required no manual intervention, and all processes were completed in a single clamping operation.

[0101] The first-piece inspection report after processing shows that all critical dimensions meet the drawing requirements, the maximum spatial position error is 0.018mm (requirement ≤0.02mm), and the surface roughness is... With a diameter of ≤ 0.8 μm, the processing efficiency is improved by about 40% compared to the traditional multiple clamping method, and the yield rate is increased from the traditional 85% to over 98%.

[0102] In summary, the processing method provided by this invention is not only applicable to the knotter frame, but can also be extended to the precision, efficient and automated processing of complex parts with similar irregular shapes, thin walls and deep cavities in other agricultural machinery, automotive parts and aerospace fields. It has extremely high industrial practical value and broad application prospects.

Claims

1. A method for processing irregularly shaped knotter parts based on feature projection and adaptive loop search, characterized in that, Includes the following steps: S1 acquires the 3D model data of the knotter's irregular part, calculates the principal tensile direction of the model using principal component analysis, and establishes a composite machining coordinate system by combining the tooling positioning strategy based on the datum plane and process holes. S2 traverses the model topology surfaces and selects the set of surfaces to be projected based on the angle between the normal of each topology surface and the main stretching direction, the wall thickness, and the relative orientation with the tooling positioning reference surface. S3 constructs an adaptive projection plane with the geometric center of the part as the origin and the main stretching direction as the normal. The set of surfaces to be projected is projected onto this plane to obtain a two-dimensional projection edge set. A bidirectional loop search is performed using the maximum rotation angle priority strategy to generate two-dimensional closed loops representing different features. S4 generates contour milling paths and hole machining paths based on the properties of the two-dimensional closed loop. For the identified oblique hole features, it automatically calculates the avoidance micro-swing angle to generate interference-free five-axis linkage tool axis vectors and finally outputs five-axis linkage machining code. The S5 transmits the machining code to the five-axis machining center, clamps the workpiece once, and completes the machining of all features.

2. The processing method according to claim 1, characterized in that: In step S1, principal component analysis is used to construct the covariance matrix for all surface point cloud data of the part's 3D model: ； Solve for eigenvalues ​​and eigenvectors, and determine the eigenvector corresponding to the largest eigenvalue as the principal stretching direction; for parts with significant slender features or those stretched from the same contour along a certain direction, use the principal component direction of the overall point cloud as the optimal projection direction. in For the first A vector of coordinates of sampling points Let be the centroid coordinate vector of all sampling points. The total number of sampling points. Transpose a matrix / vector.

3. The processing method according to claim 1, characterized in that: The specific filtering rule in step S2 is as follows: If a certain topological surface satisfies: ； Or wall thickness Less than the preset threshold ,Right now ; or the angle between its normal and the tooling positioning reference plane satisfies: ； Then add the topological surface to the set of surfaces to be projected; in The threshold for thin-walled components is preset based on material properties and part stiffness. and To preset the angle threshold according to the machining accuracy requirements, The unit vector in the main stretching direction. The unit vector is the normal to the topological surface. To determine the tolerance for verticality, for Normal to the tooling reference plane The included angle.

4. The processing method according to claim 1, characterized in that: The maximum rotation angle priority bidirectional loop search algorithm in step S3 includes: starting from the starting edge in the deduplicated two-dimensional projected edge set, calculating the clockwise rotation angle between the tangent of the previous edge and the tangent of all candidate adjacent edges at its endpoint, and selecting the candidate edge with the largest rotation angle as the next connecting edge, repeating this process until a closed loop is formed; performing this process along the vector direction of the starting edge and its opposite direction respectively to obtain all internal minimum two-dimensional loops and outer boundary two-dimensional loops.

5. The processing method according to claim 1, characterized in that: The step S4 of generating the five-axis linkage machining code includes: back-projecting the two-dimensional closed loop back into three-dimensional space; for the counterclockwise outer boundary loop, generating a three-dimensional contour machining path; for the clockwise inner loop, determining the roundness using a roundness algorithm, and if the roundness... satisfy: ； The ring is then identified as a precision hole, in which Let be the area of ​​the ring. Let be the circumference of the ring. Set a preset roundness threshold and generate hole machining cycle code; For the oblique hole feature, its tool axis vector From the formula: ； Confirmed, among which For the ideal hole axis vector, The avoidance angle is automatically calculated based on the surrounding interference model. The calculation method is as follows: Using the axis as the projection direction along the normal of the interference plane, with a preset step size... Gradually deflect the tool axis until the tool envelope plane is at the nearest interference plane. satisfy: ； in To set a safe distance.

6. The processing method according to claim 1, characterized in that: In step S1, the method for establishing the composite machining coordinate system is as follows: the positioning surface of the irregular support block on the tooling is taken as the XY plane reference, the axis of the precision positioning pin is taken as the Z-axis direction, the direction of the line connecting the two process holes is taken as the X-axis direction, and the origin is set at the positioning center of the tooling, so that the digital model coordinate system and the physical clamping coordinate system are completely coincident.

7. The processing method according to claim 1, characterized in that: Step S5 further includes: when the CNC system executes the code segment corresponding to the thin-walled feature identified in step S2, the system automatically reduces the spindle feed rate to a preset safe feed rate. It also sends a command to the tooling control system to switch the clamping mode to low-pressure floating follow mode, maintaining the clamping force at the preset low-pressure threshold. Within a certain range, to prevent workpiece deformation.

8. The method according to claim 7, characterized in that: In step S5, the machining process also includes a real-time monitoring and feedback adjustment step: the CNC system collects signals in real time through the spindle load sensor and the force sensor on the tooling. When the spindle load exceeds the preset threshold or the clamping force deviates from the set range, the system automatically adjusts the feed rate and clamping force to maintain the stability of the machining process.

9. The processing method according to claim 1, characterized in that: In step S2, the method for identifying thin-walled feature surfaces is as follows: by calculating the minimum local wall thickness of the topological surface. ,like ; Then the surface is determined to be a thin-walled feature surface; among them, for aluminum alloy parts =3mm, for steel parts =2mm.

10. The processing method according to claim 1, characterized in that: In step S4, for the identified deep cavity area, the system automatically shortens the tool extension length and adopts climb milling to reduce cutting vibration; for the thin-walled area, the system automatically generates a layered fine milling path, and the cutting depth of each layer is automatically determined according to the material hardness and tool parameters.

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