Multi-layer stereoscopic relief creative ornament piece numerical control synchronous precision engraving integrated processing method

Abstract

The present application relates to the technical field of numerical control engraving processing, and discloses a multi-layer three-dimensional relief creative ornament numerical control synchronous fine engraving integrated processing method, comprising the following operation steps: step S1: material pretreatment and artistic attribute digital mapping modeling, preparing layered material (such as multi-color step wood-based panel or dyed resin composite board) with Z-axis direction color gradient characteristics. The multi-layer three-dimensional relief creative ornament numerical control synchronous fine engraving integrated processing method integrates the engraving path of the multi-layer structure in the same processing program, and is supplemented by a one-time clamping positioning mode combined with vacuum adsorption and peripheral pressing plate, thereby completely eliminating the reference drift and form tolerance accumulation problems caused by repeated clamping and repeated tool setting in traditional split processing. According to actual measurement, the profile coincidence error between the bottom layer, the middle layer and the top layer can be controlled within ±0.02 mm, and the level corresponding accuracy between the multi-layer reliefs is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of CNC engraving technology, specifically to a method for integrated CNC synchronous fine engraving of multi-layer three-dimensional relief cultural and creative ornaments. Background Technology

[0002] In recent years, with the rapid development of the cultural tourism and creative industries, the market demand for multi-layered three-dimensional relief cultural and creative ornaments (such as landscape relief ornaments, intangible cultural heritage pattern derivatives, urban IP three-dimensional sculptures, and ancient style cultural and creative crafts) has continued to grow. The materials cover a variety of types, including solid wood, MDF, resin, acrylic, gypsum and composite boards. These products are required to have a rich sense of three-dimensional layering, fine surface texture and high artistic expression, while also meeting the commercial needs of mass production and uniformity.

[0003] Currently, traditional processing methods often involve carving the parts separately and then gluing them together, or performing multiple clamping steps for processing. For example, the bottom layer is processed first, and then the tool is changed or the position is repositioned to process the top layer. This method has the following shortcomings: Poor positioning accuracy: Multiple clamping operations lead to inconsistent references, and the relative positions between different layers of relief are prone to deviation, affecting the overall artistic effect; Inefficient: The process is fragmented, requiring multiple tool changes, tool settings, and manual intervention, making it unsuitable for mass production; Uneven surface quality: Layered processing is prone to producing steps or tool marks at the joints between layers, resulting in a large amount of manual polishing work in the later stage; Material waste: To ensure the stability of secondary clamping, a large clamping allowance needs to be reserved, which increases material costs. Summary of the Invention

[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a CNC synchronous precision carving integrated processing method for multi-layer three-dimensional relief cultural and creative ornaments. It has the advantages of high-precision one-time clamping, multi-tool collaborative synchronous processing, and smooth transition between layers, and solves the problems of accumulated form and position tolerances and low processing efficiency caused by the need for separate processing and assembly of multi-layer structures.

[0005] (II) Technical Solution To achieve the aforementioned goals of high-precision single-clamping, multi-tool collaborative synchronous machining, and smooth transition between layers, this invention provides the following technical solution: A CNC synchronous precision carving integrated machining method for multi-layer three-dimensional relief cultural and creative ornaments, comprising the following operational steps: Step S1: Material pretreatment and digital mapping modeling of artistic attributes Prepare layered materials with color gradient characteristics in the Z-axis direction (such as multi-color wood laminate or dyed resin composite board), and establish a mathematical mapping relationship between the material color gradient and the Z-axis depth data of the three-dimensional relief model, so that the carving depth corresponds one-to-one with the material's exposed color, forming the artistic effect of "carving path is color rendering path". Step S2: Construction of Composite 3D Model and Adaptive Layered Slicing Based on a CAD system that supports hybrid modeling of STL meshes and surfaces, two-dimensional cultural and creative patterns are converted into three-dimensional relief grayscale images and wrapped onto the surface of the ornament base to generate a composite three-dimensional model. Then, adaptive slicing is performed according to the curvature changes of the model surface, generating thin slices in areas with rich details and thick slices in flat areas, thus controlling the processing time while ensuring accuracy. Step S3: Layered parameter preset and multi-spindle differentiated toolpath planning The model is divided into three layers: the bottom base, the middle main relief, and the surface fine decoration. The processing depth, allowance, and precision parameters of each layer are set independently. Differentiated toolpaths are assigned for dual-spindle or triple-spindle synchronous engraving machines: the roughing spindle uses a large-diameter tool to quickly remove the allowance, and the engraving spindle uses a small-diameter ball end mill to finish along the normal direction. Microsecond-level synchronous control of starting and stopping multiple spindles is achieved. Step S4: Digital Twin Virtual Simulation and Processing Prediction By importing the layered machining scheme into the digital twin simulation platform, a 1:1 full-process virtual engraving simulation is performed to detect problems such as tool interference, interlayer connection deviation, and edge chipping risk in advance, and to automatically optimize the tool path and cutting parameters to generate a mass-producible, error-free CNC machining program. Step S5: Integrated synchronous precision carving The raw materials are clamped onto the five-axis linkage CNC engraving machine in one go, and the synchronous processing mode is started: the roughing spindle quickly forms the basic outline, the middle spindle simultaneously completes the three-dimensional relief body forming, and the engraving spindle, based on the "color level-grayscale" mapping relationship, controls the cutting depth to synchronously show the internal color gradient of the material. The three processes are carried out in parallel at the same station, forming in one go, with seamless transition between the curved surfaces of the layers. Step S6: Online detection and real-time dynamic error compensation During the processing, high-precision probes or grating rulers are used to collect workpiece surface data in real time. Combined with dynamic error compensation algorithms, the Z-axis depth deviation caused by tool wear, temperature deformation, and material stress release is corrected to ensure that the dimensional accuracy of batch products is controlled within ±0.02mm. Step S7: Integrated flexible micro-polishing process at the CNC end. After the fine carving is completed, the equipment automatically switches to the flexible polishing module to perform differentiated polishing on different areas of the multi-layer relief (deep planar grinding, surface fine texture repair, and rounded corner transition), removing tool marks and burrs, preserving the three-dimensional sense of layering, and eliminating the need for manual secondary polishing; Step S8: Online visual quality inspection and data closed-loop backtracking Equipped with a high-definition visual inspection system, it automatically collects data such as finished product size, layer height difference, and texture integrity, compares them with standard models, and automatically sorts out good products; at the same time, it synchronizes the data of the entire processing process to the digital twin system to complete data archiving and provide data support for subsequent style iteration and parameter optimization.

[0006] Furthermore, in step S1, the mapping relationship between the material color gradient and the Z-axis depth of the relief model is either a linear mapping or a non-linear mapping. When a non-linear mapping is used, the system automatically adjusts the color change rate according to the local detail density of the model surface, so that the dense detail area obtains a more vivid color contrast and enhances the artistic expression of the relief.

[0007] Furthermore, in step S2, the thickness range of the adaptive slice is 0.05mm to 2.0mm; in areas where the radius of curvature of the model is less than 5mm, the slice thickness is 0.05mm to 0.15mm; in flat areas where the radius of curvature is greater than 20mm, the slice thickness is 0.5mm to 2.0mm; in intermediate curvature areas, linear interpolation is used to determine the slice thickness in order to balance processing accuracy and efficiency.

[0008] Furthermore, in step S3, the multi-spindle differentiated toolpath planning is specifically as follows: the roughing spindle reserves a fine carving allowance of 0.3mm to 0.5mm, and uses a spiral downward cutting or oblique downward cutting method to avoid vertical impact; the fine carving spindle uses the equal residual height method to generate toolpaths, and the spacing between adjacent toolpaths is adaptively calculated according to the tool diameter and allowable residual height to ensure that the surface roughness Ra≤0.4μm.

[0009] Furthermore, in step S5, during synchronous fine carving, the machining directions of the roughing spindle and the fine carving spindle are orthogonal to each other or arranged at a set angle. On the basis of the three-axis linkage of X / Y / Z, the two spindles combine the rotation of the A-axis and the swing of the B-axis to achieve five-axis linkage. The roughing and fine carving processes overlap and advance on the time axis. The spatial safety distance of the overlapping area is not less than 5mm, which is monitored in real time by the CNC system to avoid interference.

[0010] Furthermore, in step S6, online detection and real-time error dynamic compensation include the following sub-steps: triggering probe measurement at a set machining depth or a set time interval to obtain the actual Z-coordinate value of the workpiece surface; comparing the measured value with the coordinates of the corresponding point in the theoretical model to calculate the deviation; using exponential smoothing or Kalman filtering algorithms to filter the continuous measurement data to eliminate random noise; and superimposing the filtered deviation value into the subsequent toolpath Z-axis command to achieve closed-loop dynamic compensation, with a compensation response time of no more than 50ms.

[0011] Furthermore, in step S8, the online visual quality inspection and data closed-loop backtracking are specifically implemented as follows: 3D point cloud data of the finished product is acquired using structured light or laser triangulation, and best-fit comparison is performed with the standard model to detect interlayer height difference, surface contour deviation, and texture integrity; defective products with deviations exceeding the standard are automatically marked and separated; at the same time, the detection data is fed back to the digital twin system, and the system automatically updates the tool wear prediction model and material deformation correction parameters for subsequent workpiece processing parameter pre-adjustment, forming a full-process self-learning closed loop.

[0012] (III) Beneficial Effects Compared with existing technologies, this invention provides a CNC synchronous precision carving integrated processing method for multi-layer three-dimensional relief cultural and creative ornaments, which has the following beneficial effects: 1. This integrated CNC synchronous precision carving method for multi-layered three-dimensional relief cultural and creative ornaments integrates the carving paths of multiple layers into a single processing program. It utilizes a one-time clamping and positioning method combining vacuum adsorption and external pressure plates, completely eliminating the problems of datum drift and accumulated geometric tolerances caused by multiple clamping and repeated tool setting in traditional split processing. Actual measurements show that this invention can control the contour overlap error between the bottom, middle, and top layers within ±0.02mm, significantly improving the layer correspondence accuracy between multiple reliefs. It is particularly suitable for the mass production of high-end cultural and creative ornaments with complex interlocking structures, effectively reducing the scrap rate.

[0013] 2. This integrated CNC synchronous fine carving processing method for multi-layer three-dimensional relief cultural and creative ornaments adopts a dual-spindle collaborative operation mechanism. The first spindle is responsible for the large-scale equal-height fine carving of the main three-dimensional layer, while the second spindle simultaneously follows up to finely depict the top layer details and edge lines. The rough carving, fine carving, and detail carving work that originally needed to be completed on two machines or in three to four processes is integrated into one loading and unloading. This synchronous processing mode can shorten the total processing time by 40% to 60%, while avoiding the turnover of semi-finished products and secondary waiting time, which greatly improves the equipment utilization rate and output per unit time, and provides an efficient solution for the mass customization production of cultural and creative products.

[0014] 3. This integrated CNC synchronous precision carving method for multi-layer three-dimensional relief cultural and creative ornaments introduces a spiral angle continuous path algorithm in the transition area between layers, and combines it with real-time adaptive adjustment of the feed rate based on force control sensor feedback. This effectively eliminates the unavoidable annular step marks and tool marks at the junctions of layers in traditional layered processing. The surface roughness at the junctions between layers of the finished ornament can stably reach Ra≤0.8μm, and the texture transition is natural and coherent. Its three-dimensionality and delicacy are significantly better than those of conventional products that are carved separately and then glued together. This greatly reduces the amount of manual polishing work in the later stages, shortens the product delivery cycle, and at the same time preserves the original artistic details designed by the creator, thereby enhancing the added value of the final product. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the overall process flow of the integrated processing method of the present invention. Figure 2 This is a schematic diagram of the structural layout of the multi-spindle synchronous machining system of the present invention; Figure 3 This is a schematic diagram of the architecture of the digital twin and data closed-loop backtracking system of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] Please see Figure 1-3 A method for CNC synchronous precision carving integrated processing of multi-layer three-dimensional relief cultural and creative ornaments includes the following operation steps: Step S1: Material pretreatment and digital mapping modeling of artistic attributes Prepare layered materials with color gradient characteristics in the Z-axis direction (such as multi-color wood laminate or dyed resin composite board), and establish a mathematical mapping relationship between the material color gradient and the Z-axis depth data of the three-dimensional relief model, so that the carving depth corresponds one-to-one with the material's exposed color, forming the artistic effect of "carving path is color rendering path". Step S2: Construction of Composite 3D Model and Adaptive Layered Slicing Based on a CAD system that supports hybrid modeling of STL meshes and surfaces, two-dimensional cultural and creative patterns are converted into three-dimensional relief grayscale images and wrapped onto the surface of the ornament base to generate a composite three-dimensional model. Then, adaptive slicing is performed according to the curvature changes of the model surface, generating thin slices in areas with rich details and thick slices in flat areas, thus controlling the processing time while ensuring accuracy. Step S3: Layered parameter preset and multi-spindle differentiated toolpath planning The model is divided into three layers: the bottom base, the middle main relief, and the surface fine decoration. The processing depth, allowance, and precision parameters of each layer are set independently. Differentiated toolpaths are assigned for dual-spindle or triple-spindle synchronous engraving machines: the roughing spindle uses a large-diameter tool to quickly remove the allowance, and the engraving spindle uses a small-diameter ball end mill to finish along the normal direction. Microsecond-level synchronous control of starting and stopping multiple spindles is achieved. Step S4: Digital Twin Virtual Simulation and Processing Prediction By importing the layered machining scheme into the digital twin simulation platform, a 1:1 full-process virtual engraving simulation is performed to detect problems such as tool interference, interlayer connection deviation, and edge chipping risk in advance, and to automatically optimize the tool path and cutting parameters to generate a mass-producible, error-free CNC machining program. Step S5: Integrated synchronous precision carving The raw materials are clamped onto the five-axis linkage CNC engraving machine in one go, and the synchronous processing mode is started: the roughing spindle quickly forms the basic outline, the middle spindle simultaneously completes the three-dimensional relief body forming, and the engraving spindle, based on the "color level-grayscale" mapping relationship, controls the cutting depth to synchronously show the internal color gradient of the material. The three processes are carried out in parallel at the same station, forming in one go, with seamless transition between the curved surfaces of the layers. Step S6: Online detection and real-time dynamic error compensation During the processing, high-precision probes or grating rulers are used to collect workpiece surface data in real time. Combined with dynamic error compensation algorithms, the Z-axis depth deviation caused by tool wear, temperature deformation, and material stress release is corrected to ensure that the dimensional accuracy of batch products is controlled within ±0.02mm. Step S7: Integrated flexible micro-polishing process at the CNC end. After the fine carving is completed, the equipment automatically switches to the flexible polishing module to perform differentiated polishing on different areas of the multi-layer relief (deep planar grinding, surface fine texture repair, and rounded corner transition), removing tool marks and burrs, preserving the three-dimensional sense of layering, and eliminating the need for manual secondary polishing; Step S8: Online visual quality inspection and data closed-loop backtracking Equipped with a high-definition visual inspection system, it automatically collects data such as finished product size, layer height difference, and texture integrity, compares them with standard models, and automatically sorts out good products; at the same time, it synchronizes the data of the entire processing process to the digital twin system to complete data archiving and provide data support for subsequent style iteration and parameter optimization.

[0018] In the implementation of the case, in step S1, the mapping relationship between the material color gradient and the Z-axis depth of the relief model is either a linear mapping or a non-linear mapping. When a non-linear mapping is used, the system automatically adjusts the color change rate according to the local detail density of the model surface, so that the dense detail area can obtain a more vivid color contrast and enhance the artistic expression of the relief.

[0019] Among them, linear mapping means that the color value changes proportionally and uniformly with the depth of the Z-axis, which is suitable for relief models with gentle terrain undulations and simple hierarchical structures; nonlinear mapping uses S-curve functions or exponential functions for color allocation, which makes the color difference between the low and high areas more pronounced and the transition in the middle area smoother.

[0020] Specifically, before layering the 3D model, the CAM system first performs surface curvature analysis on the model's triangular mesh, calculates the average curvature and Gaussian curvature at each vertex, and generates a local detail density map based on this. The density map is then normalized to weight coefficients between 0 and 1 and passed to the color mapping algorithm. The nonlinear mapping formula is as follows:

[0021] in, This is an adaptive index, and its value is negatively correlated with the local detail density D: when D > 0.7 (high detail region), Using a value of 0.6 to 0.8 allows for rapid color transitions within a relatively small Z-axis variation range; when D < 0.3 (flat region), Use a value of 1.2 to 1.5 to make the color transition smoother and avoid obvious color gradation breaks in flat areas of the texture.

[0022] Through the above nonlinear adaptive mapping mechanism, the areas with rich details such as trees, roof tiles, and clothing patterns in the landscape relief can obtain sharp and clear color gradation, while the large areas of sky, water or base background maintain soft and natural color gradation. This visually enhances the primary and secondary relationships and artistic appeal of the multi-layered three-dimensional relief, while avoiding the phenomenon of details being "submerged" due to uniform color mapping.

[0023] In the implementation of the case, in step S2, the layer thickness of the adaptive slice ranges from 0.05mm to 2.0mm; in areas where the radius of curvature of the model is less than 5mm, the slice thickness is 0.05mm to 0.15mm; in flat areas where the radius of curvature is greater than 20mm, the slice thickness is 0.5mm to 2.0mm; in intermediate curvature areas, linear interpolation is used to determine the slice thickness in order to balance processing accuracy and efficiency.

[0024] The radius of curvature is obtained by performing layer-by-layer cross-sectional analysis of the STL model using slicing software. The average radius of curvature of the contour line of each slice layer is calculated at the height of each slice layer, which serves as the basis for determining the slice thickness of that layer.

[0025] Specifically, in the slicing module, the basic safety layer thickness is set to 0.1mm. The system traverses the cross-sectional contour lines of each layer of the model, performs least-squares circular arc fitting on the discrete point set on the contour lines, and obtains the local radius of curvature R at each point. When R < 5mm, the layer thickness is forcibly locked within the range of 0.05mm to 0.15mm to ensure that fine features (such as facial features and leaf veins) have enough layers in the Z direction to restore details. When R > 20mm, the layer thickness is relaxed to 0.5mm to 2.0mm to reduce the total number of layers, shorten the calculation time, and shorten the processing path length. For the intermediate region of 5mm ≤ R ≤ 20mm, the layer thickness is calculated according to the following linear interpolation formula:

[0026] That is, for every 1mm increase in the radius of curvature, the layer thickness increases by approximately 0.13mm, achieving a smooth trade-off between accuracy and efficiency; By employing the aforementioned variable layer thickness adaptive slicing strategy, this invention reduces the overall number of processing layers by approximately 35% to 50% compared to uniform 0.1mm slicing, while ensuring the quality of local detail carving. This significantly shortens the post-processing toolpath calculation time and reduces tool lifting and idle travel during fine carving, thereby improving overall processing efficiency.

[0027] In the implementation of the case, in step S3, the multi-spindle differentiated toolpath planning is as follows: the roughing spindle reserves a fine engraving allowance of 0.3mm to 0.5mm, and uses a spiral downward or oblique downward cutting method to avoid vertical impact; the fine engraving spindle uses the equal residual height method to generate toolpaths, and the spacing between adjacent toolpaths is adaptively calculated according to the tool diameter and allowable residual height to ensure that the surface roughness Ra≤0.4μm.

[0028] The roughing spindle is equipped with a carbide corrugated end mill with a diameter of 6mm to 10mm to quickly remove large volume allowances between layers; the finishing spindle is equipped with a tapered ball end mill or a round nose end mill with a diameter of 0.5mm to 4mm to complete the final contour shaping.

[0029] Specifically, this includes: In the toolpath planning stage, firstly, a "layer priority" or "depth priority" cutting strategy is set for the roughing spindle. To avoid impact chipping when the tool is inserted vertically into the workpiece, all cutting actions are set to helical cutting (helix radius 3~5mm, helix angle 3°~5°) or oblique cutting (oblique length ≥10mm, cutting angle ≤5°). The depth of cut for each layer in roughing is controlled at 0.5mm~2.0mm, and the step distance is 50%~70% of the tool diameter. After machining, a 0.3mm~0.5mm allowance for fine carving is evenly left on the surface of each layer.

[0030] Then, the system generates a finishing path for the engraving spindle using the equal residual height method. Based on the actual ball end radius R of the engraving tool and the preset allowable residual height h (set to 0.01mm~0.03mm), the system automatically calculates the maximum allowable distance L between two adjacent toolpaths. The calculation formula is as follows:

[0031] When using an R3 ball end mill with an allowable residual height h=0.01mm, the calculated step distance is approximately 0.34mm. When h is increased to 0.03mm, the step distance can be expanded to approximately 0.59mm. Users can freely adjust the residual height threshold according to appearance requirements. The system automatically recalculates the step distance, eliminating the need for repeated manual trial cuts. During the fine engraving process, the spindle speed is set to 20000~30000rpm, and the feed rate is 1500~3000mm / min. Combined with micro-oil mist lubrication, a smooth and uniform engraved surface is obtained.

[0032] Through the toolpath planning method of roughing and finishing separation and differentiated parameter configuration, the roughing spindle can efficiently remove material under conditions of large depth of cut and high feed, while the finishing spindle can finely shape under conditions of small cutting amount and high speed. The two complement each other's advantages. Actual tests show that the surface roughness of multi-layer relief samples processed by this method can be stably achieved to Ra≤0.4μm, with smooth interlayer connections and no steps. They can be directly used for display-grade cultural and creative products without additional polishing.

[0033] In the implementation of the case, during the synchronous fine carving process in step S5, the machining directions of the roughing spindle and the fine carving spindle are orthogonal to each other or at a set angle. The two spindles achieve five-axis linkage by combining A-axis rotation and B-axis oscillation on the basis of X / Y / Z three-axis linkage. The roughing and fine carving processes are carried out overlappingly on the time axis, and the spatial safety distance of the overlapping area is not less than 5mm. The CNC system monitors the process in real time and avoids interference.

[0034] Specifically, the orthogonal or angled layout is as follows: the roughing spindle is installed vertically (along the Z-axis) to transmit the main cutting force in the vertical direction; the engraving spindle is installed at an angle, with its axis at an angle of 15° to 45° with the Z-axis, so as to cut into complex undercut areas and deep and narrow grooves from the side, avoiding collision between the tool holder and the workpiece. In the five-axis linkage, the A-axis is a swing axis that rotates around the X-axis, and the B-axis is a swing axis that rotates around the Y-axis. The combination of the two allows the workpiece to be presented in any posture within the machining range of the two spindles.

[0035] Specifically, this includes: establishing a dual-spindle collaborative motion model within the CNC system. The system uses the motion path of the roughing spindle as the main trajectory and the path of the finishing spindle as the secondary trajectory. Both share the same workpiece coordinate system. In terms of time axis planning, the finishing section in the roughing process (i.e., the area that has completed roughing and is in the semi-finishing stage) is time-aligned with the starting point of the finishing process of the finishing spindle, so that the two processes can perform processing on different areas of the same workpiece within the same time period.

[0036] To prevent collisions between the two spindles in the same spatial area, the system has the following preset safety strategies: (1) Static safety distance: The three-dimensional Euclidean distance between the end tools of the two spindles is not less than 5mm at any time. This value is measured and fed back in real time by the laser interferometer built into the machine tool; (2) Dynamic interference warning: When the distance between the two spindles approaches 8mm, the system issues a deceleration warning; when it approaches 5mm, the system automatically triggers priority arbitration, prioritizing the reduction of the feed speed of the fine carving spindle or slowing down its movement, and restoring synchronization after the roughing spindle leaves the safe distance; (3) Path pre-check: In the post-processing stage, the interference and collision simulation of the dual spindle full motion trajectory is performed by Vericut or NX simulation software. Only after confirming that there are no errors can the path be executed on the machine.

[0037] Meanwhile, the introduction of the five-axis linkage function allows the A-axis and B-axis to dynamically adjust the workpiece posture according to the normal direction of the model surface. When machining complex curved surfaces (such as relief spherical domes or concave arc surfaces), the system automatically rotates the workpiece to the optimal machining angle to ensure that the two spindles always contact the machining surface in a nearly perpendicular direction, thereby reducing tool deformation caused by lateral cutting forces.

[0038] By combining the above-mentioned orthogonal / angled dual-spindle layout with five-axis linkage technology, this invention achieves a deep overlap between roughing and fine carving processes in time and space, reducing the total processing time of a single piece by about 50% compared to traditional sequential processing. At the same time, five-axis linkage avoids the bottom interference and processing dead angle problems caused by insufficient tool tilt angle when using fixed three-axis processing, enabling the side walls and deep groove areas of multi-layer reliefs to be completely carved in one go, greatly improving the machinability of complex cultural and creative ornaments and the surface quality of finished products.

[0039] In the implementation of the case, step S6, online detection and real-time error dynamic compensation includes the following sub-steps: triggering probe measurement at a set machining depth or set time interval to obtain the actual Z coordinate value of the workpiece surface; comparing the measured value with the corresponding point coordinate of the theoretical model to calculate the deviation; using exponential smoothing or Kalman filtering algorithms to filter the continuous measurement data to eliminate random noise; superimposing the filtered deviation value into the subsequent toolpath Z-axis command to achieve closed-loop dynamic compensation, with a compensation response time of no more than 50ms.

[0040] The measurement is triggered once every 1mm to 3mm of machining depth to monitor the cumulative Z-axis error caused by tool wear, thermal expansion, or material hardness fluctuations. The measurement is triggered once every 30 to 60 seconds to provide more detailed monitoring in high-density areas and to detect sudden deviations in a timely manner. The probe is a high-precision contact trigger probe (such as the Renishaw OMP series) with a repeatability accuracy of ≤±1μm.

[0041] Specifically, this includes pre-embedding the coordinates of measurement points into the original toolpath generated by CAM. The strategy for selecting measurement points is as follows: (1) Force measurement points to be set at key feature points of the model (such as the highest point of a person's face, the pointed corners of pavilions and roofs, the tips of tree branches, etc.); (2) After each layer of slicing is completed, at least 4 measurement points shall be evenly distributed along the contour of that layer; (3) In areas with drastic curvature changes (curvature radius R < 3 mm), the spacing between measurement points should be reduced to within 5 mm.

[0042] When the system reaches the preset measurement point, the CNC system pauses the machining feed and drives the probe to contact the workpiece surface at a probing speed of 100mm / min~200mm / min. After the probe is triggered, the system records the current Z-axis mechanical coordinate value and subtracts it from the theoretical Z-value at that point to obtain the difference. To improve measurement reliability, each measurement point was probed three times, and the median value was taken as the valid data.

[0043] Subsequently, the continuously collected deviation data sequence is input into the filtering module. When the exponential smoothing algorithm is used, its recursive formula is:

[0044] in, This is a smoothing factor, ranging from 0.3 to 0.7. A larger value results in faster tracking response but decreased noise immunity; it is typically used during the finishing stage. =0.4, balancing real-time performance and stability.

[0045] When using the Kalman filter algorithm, the system establishes state equations and observation equations. Using the error estimate from the previous moment and the measurement from the current moment, the current optimal error estimate is recursively calculated. Its convergence speed is better than that of exponential smoothing, making it suitable for situations where the noise characteristics are unknown.

[0046] After filtering, the compensation value = By superimposing the compensation onto the Z-axis interpolation command of the subsequent toolpath through the real-time compensation interface of the CNC system (such as the CYCLE996 function of Siemens 840D or the error compensation macro program of FANUC), the system controls the single compensation response cycle to within 50ms, that is, completes the entire process of "measurement → filtering → compensation value output" within 50ms, ensuring that the compensation command has taken effect before the next interpolation cycle arrives.

[0047] Through the above-mentioned online detection and real-time error dynamic compensation mechanism, the present invention can promptly correct Z-axis dimensional deviations caused by tool wear, thermal deformation, and uneven material hardness during continuous processing. Actual measurements show that when processing 10 products from the same batch, the cumulative Z-axis deviation under uncompensated conditions can reach 0.08mm~0.15mm, while after enabling dynamic compensation, the deviation is stably controlled within ±0.015mm, significantly improving the consistency of batch processing and product yield.

[0048] In the implementation of the case, step S8, the specific implementation of online visual quality inspection and data closed-loop backtracking is as follows: the three-dimensional point cloud data of the finished product is obtained by using structured light or laser triangulation, and the best fit comparison is performed with the standard model to detect the height difference between layers, surface contour deviation and texture integrity; defective products with deviations exceeding the standard are automatically marked and separated; at the same time, the detection data is fed back to the digital twin system, and the system automatically updates the tool wear prediction model and material deformation correction parameters for subsequent workpiece processing parameter pre-adjustment, forming a full-process self-learning closed loop.

[0049] Among them, the structured light measurement method is suitable for wooden and resin ornaments with rich surface textures and diverse colors. By projecting coded structured light and decoding phase information, high-density point clouds (resolution ≥ 0.05 mm) can be quickly obtained. The laser triangulation measurement method is suitable for metal materials with strong reflectivity. It uses line laser scanning to obtain contour data. The digital twin system is a virtual mapping platform that corresponds one-to-one with the physical machine tool. It integrates a tool wear evolution model, a material cutting deformation finite element model, and a processing parameter optimization database.

[0050] Specifically, this includes: after the workpiece is processed and cleaned, it is placed at the inspection station. The system activates a structured light scanner (such as the GOMATOS series or equivalent domestic equipment) to project and acquire images of the ornament from at least three different angles. Each acquisition takes no more than 5 seconds. The acquired multi-view point cloud data is stitched and fused using the Iterative Closest Point (ICP) algorithm to form a complete 3D point cloud model with a point cloud density of no less than 200 points / mm. 2 .

[0051] Then, the system performs a best-fit comparison between the collected point cloud data and the standard STL model from the design phase. The fitting process uses the least squares method to calculate the optimal spatial transformation matrix (containing 3 translations and 3 rotations) to maximize the overlap between the point cloud and the model. During the comparison and analysis, the following key quality indicators are the focus: (1) Height difference between layers: The actual height difference between each relief layer deviates from the design value by ≤ ±0.05mm; (2) Surface profile deviation: The root mean square error (RMS) of the normal distance between the point cloud and the model is ≤0.08mm; (3) Texture integrity: By calculating the point cloud density and void ratio of the texture area, it is determined whether there is any missing toolpath or edge chipping.

[0052] For any workpiece that exceeds the allowable range in any of the above three indicators, the system automatically pushes it into the defective product collection box via a pneumatic lever or robotic arm, and prints a label indicating the item that exceeds the standard and the deviation data.

[0053] Simultaneously, all inspection data (including deviation values ​​and distribution patterns of qualified and defective products) are uploaded to the digital twin system in real time via industrial Ethernet. The digital twin system summarizes and analyzes the actual deviation data of the workpiece with historical data and performs the following self-learning update operations: (1) Tool wear prediction model update: Based on the cumulative machining time of the engraving tool and the trend of surface roughness change, the tool wear curve is refitted to predict the remaining life of the current tool and the pre-offset amount to be compensated for the next piece of machining; (2) Material deformation correction parameter update: By comparing the actual deformation after cutting of different batches of blank materials, the elastic modulus and Poisson's ratio parameters of the material in the finite element model are corrected to make the simulation deformation prediction before the next processing more accurate. (3) Pre-adjustment of machining parameters: Based on the above analysis results, the system automatically generates an optimized machining program for subsequent workpieces of the same model, including appropriately reducing or increasing the allowance, adjusting the spindle speed and feed rate, etc.

[0054] Through the aforementioned online visual quality inspection and data closed-loop traceability mechanism, this invention establishes a self-learning closed loop for the entire process of "processing → inspection → analysis → optimization → reprocessing". As the number of processing batches increases, the system accumulates more and more process knowledge, and the accuracy of the recommended processing parameters continues to improve. Experimental verification shows that the average pass rate of the first batch of products is about 87%, while after 10 batches of closed-loop optimization, the pass rate can be stably increased to over 96%, significantly reducing quality fluctuations and material waste in the mass production of cultural and creative ornaments.

[0055] In summary, this integrated CNC synchronous precision carving method for multi-layer three-dimensional relief cultural and creative ornaments integrates the carving paths of multiple layers into the same processing program, and uses a one-time clamping and positioning method combining vacuum adsorption and external pressure plates. This completely eliminates the problems of datum drift and cumulative geometric tolerances caused by multiple clamping and repeated tool setting in traditional split processing. Actual measurements show that this invention can control the contour overlap error between the bottom, middle and top layers within ±0.02mm, significantly improving the layer correspondence accuracy between multiple reliefs. It is especially suitable for the mass production of high-end cultural and creative ornaments with complex interlocking structures, effectively reducing the scrap rate.

[0056] Furthermore, by adopting a dual-spindle collaborative operation mechanism, where the first spindle is responsible for the large-scale, contour-equal carving of the main three-dimensional layer, while the second spindle simultaneously follows up to finely depict the top layer details and edge lines, the rough carving, fine carving, and detail carving work that originally required two machines or three to four processes is integrated into a single loading and unloading process. This synchronous processing mode can shorten the total processing time by 40% to 60%, while avoiding the turnover of semi-finished products and secondary waiting time, greatly improving equipment utilization and output per unit time, and providing an efficient solution for the mass customization production of cultural and creative products.

[0057] Furthermore, by introducing a spiral angle continuous path algorithm in the interlayer transition area and combining it with real-time adaptive adjustment of the feed rate based on force control sensor feedback, the unavoidable annular step marks and tool marks at the junctions of layers in traditional layered processing are effectively eliminated. The surface roughness at the junctions of the layers of the finished ornament can stably reach Ra≤0.8μm, and the texture transition is natural and coherent. Its three-dimensionality and delicacy are significantly better than those of products that are conventionally carved separately and then glued together. This greatly reduces the amount of manual grinding and polishing work in the later stages, shortens the product delivery cycle, and at the same time preserves the original artistic details designed by the creator, thereby enhancing the added value of the final product.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0059] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for CNC synchronous precision carving integrated processing of multi-layer three-dimensional relief cultural and creative ornaments, characterized in that: The following steps are included: Step S1: Material pretreatment and digital mapping modeling of artistic attributes Prepare layered materials with color gradient characteristics in the Z-axis direction (such as multi-color wood laminate or dyed resin composite board), and establish a mathematical mapping relationship between the material color gradient and the Z-axis depth data of the three-dimensional relief model, so that the carving depth corresponds one-to-one with the material's exposed color, forming the artistic effect of "carving path is color rendering path". Step S2: Construction of Composite 3D Model and Adaptive Layered Slicing Based on a CAD system that supports hybrid modeling of STL meshes and surfaces, two-dimensional cultural and creative patterns are converted into three-dimensional relief grayscale images and wrapped onto the surface of the ornament base to generate a composite three-dimensional model. Then, adaptive slicing is performed according to the curvature changes of the model surface, generating thin slices in areas with rich details and thick slices in flat areas, thus controlling the processing time while ensuring accuracy. Step S3: Layered parameter preset and multi-spindle differentiated toolpath planning The model is divided into three layers: the bottom base, the middle main relief, and the surface fine decoration. The processing depth, allowance, and precision parameters of each layer are set independently. Differentiated toolpaths are assigned for dual-spindle or triple-spindle synchronous engraving machines: the roughing spindle uses a large-diameter tool to quickly remove the allowance, and the engraving spindle uses a small-diameter ball end mill to finish along the normal direction. Microsecond-level synchronous control of starting and stopping multiple spindles is achieved. Step S4: Digital Twin Virtual Simulation and Processing Prediction By importing the layered machining scheme into the digital twin simulation platform, a 1:1 full-process virtual engraving simulation is performed to detect problems such as tool interference, interlayer connection deviation, and edge chipping risk in advance, and to automatically optimize the tool path and cutting parameters to generate a mass-producible, error-free CNC machining program. Step S5: Integrated synchronous precision carving The raw materials are clamped onto the five-axis linkage CNC precision carving machine in one go, and the synchronous processing mode is started: the roughing spindle quickly forms the basic outline, the middle layer spindle simultaneously completes the three-dimensional relief body forming, and the precision carving spindle, based on the "color level-grayscale" mapping relationship, controls the cutting depth to synchronously show the internal color gradient of the material. The three processes are carried out in parallel at the same station, forming in one go, with seamless transition between the curved surfaces of the layers. Step S6: Online detection and real-time dynamic error compensation During the processing, high-precision probes or grating rulers are used to collect workpiece surface data in real time. Combined with dynamic error compensation algorithms, the Z-axis depth deviation caused by tool wear, temperature deformation, and material stress release is corrected to ensure that the dimensional accuracy of batch products is controlled within ±0.02mm. Step S7: Integrated flexible micro-polishing process at the CNC end. After the fine carving is completed, the equipment automatically switches to the flexible polishing module to perform differentiated polishing on different areas of the multi-layer relief (deep planar grinding, surface fine texture repair, and rounded corner transition), removing tool marks and burrs, preserving the three-dimensional sense of layering, and eliminating the need for manual secondary polishing; Step S8: Online visual quality inspection and data closed-loop backtracking Equipped with a high-definition visual inspection system, it automatically collects data such as finished product size, layer height difference, and texture integrity, compares them with standard models, and automatically sorts out good products; at the same time, it synchronizes the data of the entire processing process to the digital twin system to complete data archiving and provide data support for subsequent style iteration and parameter optimization.

2. The method for integrated CNC synchronous precision carving of multi-layer three-dimensional relief cultural and creative ornaments according to claim 1, characterized in that: In step S1, the mapping relationship between the material color gradient and the Z-axis depth of the relief model is either linear or nonlinear. When a nonlinear mapping is used, the system automatically adjusts the color change rate according to the local detail density of the model surface, so that the dense detail area can obtain a more vivid color contrast and enhance the artistic expression of the relief.

3. The method for integrated CNC synchronous precision carving of multi-layer three-dimensional relief cultural and creative ornaments according to claim 1, characterized in that: In step S2, the thickness of the adaptive slice ranges from 0.05 mm to 2.0 mm; in areas where the radius of curvature of the model is less than 5 mm, the slice thickness is 0.05 mm to 0.15 mm; in flat areas where the radius of curvature is greater than 20 mm, the slice thickness is 0.5 mm to 2.0 mm; in intermediate curvature areas, linear interpolation is used to determine the slice thickness in order to balance processing accuracy and efficiency.

4. The method for integrated CNC synchronous precision carving of multi-layer three-dimensional relief cultural and creative ornaments according to claim 1, characterized in that: In step S3, the multi-spindle differentiated toolpath planning is as follows: the roughing spindle reserves a fine carving allowance of 0.3mm to 0.5mm, and uses a spiral downward cutting or oblique downward cutting method to avoid vertical impact; the fine carving spindle generates toolpaths using the equal residual height method, and the spacing between adjacent toolpaths is adaptively calculated according to the tool diameter and allowable residual height to ensure that the surface roughness Ra≤0.4μm.

5. The method for integrated CNC synchronous precision carving of multi-layer three-dimensional relief cultural and creative ornaments according to claim 1, characterized in that: In step S5, during synchronous fine carving, the machining directions of the roughing spindle and the fine carving spindle are orthogonal to each other or at a set angle. The two spindles achieve five-axis linkage by combining A-axis rotation and B-axis oscillation on the basis of X / Y / Z three-axis linkage. The roughing and fine carving processes overlap and advance on the time axis. The spatial safety distance of the overlapping area is not less than 5mm, which is monitored in real time by the CNC system to avoid interference.

6. The method for integrated CNC synchronous precision carving of multi-layer three-dimensional relief cultural and creative ornaments according to claim 1, characterized in that: In step S6, online detection and real-time error dynamic compensation include the following sub-steps: triggering probe measurement at a set machining depth or a set time interval to obtain the actual Z coordinate value of the workpiece surface; comparing the measured value with the corresponding point coordinates of the theoretical model to calculate the deviation; using exponential smoothing or Kalman filtering algorithms to filter the continuous measurement data to eliminate random noise; and superimposing the filtered deviation value into the subsequent toolpath Z-axis command to achieve closed-loop dynamic compensation, with a compensation response time of no more than 50ms.

7. The method for integrated CNC synchronous precision carving of multi-layer three-dimensional relief cultural and creative ornaments according to claim 1, characterized in that: In step S8, the online visual quality inspection and data closed-loop backtracking are specifically implemented as follows: the three-dimensional point cloud data of the finished product is obtained by using structured light or laser triangulation, and the best fit comparison is performed with the standard model to detect the height difference between layers, surface contour deviation and texture integrity; defective products with deviations exceeding the standard are automatically marked and separated; at the same time, the detection data is fed back to the digital twin system, and the system automatically updates the tool wear prediction model and material deformation correction parameters for subsequent workpiece processing parameter pre-adjustment, forming a full-process self-learning closed loop.

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