Five-axis linkage platform-galvanometer collaborative curved surface machining method based on space curve filling

Abstract

The invention discloses a five-axis linkage platform-galvanometer collaborative curved surface machining method based on space curve filling. The method comprises the following steps: firstly, importing a three-dimensional model stored in a triangular patch format, segmenting a closed curved surface target processing area, and then obtaining a two-dimensional plane mapping graph through parameterization; a space curve is adopted to fill the pattern, and a five-axis linkage platform motion trail is obtained through smooth processing; a filling pattern and a path are reflected to a three-dimensional space, a five-axis linkage platform and galvanometer motion instruction is generated, five-axis linkage platform motion parameters are checked, and local smooth iteration is carried out if the five-axis linkage platform motion parameters do not reach the standard; calculating a laser incident angle and a focal offset distance, and iteratively optimizing a smoothing mode when the requirements are not met; and the relative positions of the five-axis linkage platform, the workpiece and the galvanometer coordinate system are determined, coordinates are converted, and the five-axis linkage platform is combined with the two-dimensional or three-dimensional galvanometer module to complete machining. According to the method, high-frequency scanning of the galvanometer and smooth motion of the five-axis linkage platform are combined, and curved surface pattern machining under comprehensive constraint of the focal offset distance and the incident angle is achieved.

Description

Technical Field

[0001] The present invention relates to the field of laser curved surface processing, and more particularly to a five-axis linkage platform-galvanometer collaborative curved surface processing method based on space curve filling. Background Art

[0002] As the core technology in the field of plane processing, the laser galvanometer processing system is mainly composed of a laser, a galvanometer scanning system and a control system. The core principle is to achieve high-speed scanning of the laser beam in a two-dimensional plane by precisely controlling the deflection angle of the galvanometer, thereby completing high-precision processing tasks. However, when the application scenario is extended to curved surface processing, the system exposes fundamental limitations: the traditional two-dimensional galvanometer lacks the ability to dynamically adjust the spatial dimension, and cannot compensate for the defocusing phenomenon caused by the change in the height of the curved surface in real time. At the same time, the laser incident angle is seriously offset, resulting in uneven energy distribution during the processing process, which ultimately causes uneven quality of the processed surface and is difficult to meet the needs of precision manufacturing.

[0003] At present, the industry has proposed a variety of solutions for galvanometer surface processing:

[0004] 3D galvanometer solution: By adding a Z-axis control function, the laser beam focus can be dynamically adjusted according to the height change of the surface. However, it is limited by the beam incident angle and is difficult to adapt to the complex processing requirements of large curvature surfaces.

[0005] Robotic collaboration solution: Utilizing the robot's multi-degree-of-freedom motion characteristics, the galvanometer's spatial position can be flexibly adjusted to ensure the stability of the laser's incident angle and focal offset distance. However, the robot's repeated positioning accuracy is insufficient and cannot meet high-precision processing scenarios.

[0006] Multi-axis linkage solution: Based on the X and Y axes of the galvanometer, a multi-axis linkage system (such as a five-axis linkage system) is constructed by adding a rotation axis or a linear axis. The coordinated movement of each axis dynamically adjusts the posture of the workpiece or the laser processing head. Among them, although the solution combining the galvanometer with the five-axis system has the flexibility of spatial posture adjustment and high motion accuracy, the current mainstream method still adopts the "surface partition approximation" strategy - the continuous surface is discretized into a large number of tiny plane segments, and the galvanometer plane is scanned segment by segment. This method has significant defects: on the one hand, a large number of splicing areas have uneven processing effects and obvious surface joints due to repeated positioning errors and heat accumulation effects; on the other hand, the frequent start and stop positioning of the five-axis linkage platform causes low efficiency of galvanometer scanning, making it difficult to achieve efficient and high-quality processing of continuous surfaces.

[0007] To address the shortcomings of existing technologies, the present invention provides a five-axis linkage platform-galvanometer collaborative surface machining method based on spatial curve filling. This method uses continuous spatial curves to fill the pattern, and then processes it through the five-axis linkage platform-galvanometer linkage to achieve curved surface machining. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a method for collaborative surface machining using a five-axis linkage platform and a galvanometer based on spatial curve filling. This method uses spatial curves to fill three-dimensional patterns, combining high-frequency scanning of the galvanometer with the smooth motion of the five-axis linkage platform to achieve surface pattern machining with comprehensive constraints on focus offset distance and incident angle.

[0009] A five-axis linkage platform-galvanometer collaborative surface processing method based on space curve filling, characterized by comprising the following steps:

[0010] (1) Importing a 3D model, parameterizing it to obtain a 2D plane mapping, and moving the pattern to the target position in the 2D plane;

[0011] (2) Fill the pattern with a spatial curve, smooth it, and obtain the motion trajectory of the five-axis linkage platform, which is then inversely mapped into three-dimensional space;

[0012] (3) Calculate the laser incident angle and focal offset distance under the motion trajectory. If the restrictions are not met, modify the smoothing method, smooth again, and iterate until the requirements are met;

[0013] (4) Generate the five-axis linkage platform and galvanometer motion instructions, check whether the speed, acceleration, jerk, etc. of each axis of the five-axis linkage platform meet the requirements, if not, smooth the local instructions, and iterate until the constraints are met;

[0014] (5) Place the workpiece, perform processing and wait for processing to be completed.

[0015] Furthermore, in step (1):

[0016] If the target processing area is on a closed surface, it must be segmented first;

[0017] The surface to be processed satisfies G 1 Curvature continuity condition;

[0018] The parameterization methods include but are not limited to ARAP parameterization, conformal mapping, and isometric mapping;

[0019] The three-dimensional model saves information in a triangular face format, including but not limited to stl and obj formats.

[0020] Furthermore, in step (2):

[0021] Space curves include but are not limited to Hilbert curves, Peano curves, Z-curves, etc.

[0022] Set the curve order and scale to adjust the density of scan lines;

[0023] For irregular patterns, first generate a space curve fill containing the pattern, and then remove the filling points outside the pattern;

[0024] Smoothing methods include but are not limited to Gaussian smoothing, Savitzky-Golay filtering and other methods, which optimize regular broken line segments into continuous smooth curves.

[0025] Furthermore, in step (5), the galvanometer scanning trajectory is generated as follows: each set of five-axis linkage platform instructions corresponds to the galvanometer scanning instruction, the movement of the five-axis linkage platform execution instruction is calculated, and the two-dimensional X and Y coordinates are saved as the galvanometer scanning trajectory.

[0026] Furthermore, in step (6):

[0027] It is necessary to determine the relative positions of the linkage platform coordinate system, the workpiece coordinate system, and the galvanometer coordinate system and perform coordinate transformation;

[0028] A five-axis machining platform is used. The platform is a rotary table type, a swing head type, or a hybrid structure. The rotation axis configuration includes at least one of the following combinations:

[0029] The C axis around the Z axis and the A axis around the X axis;

[0030] The C axis around the Z axis and the B axis around the Y axis;

[0031] A axis around the X axis and B axis around the Y axis;

[0032] The galvanometer system is configured as a two-dimensional scanning module or a three-dimensional galvanometer module with an integrated planar scanning component.

[0033] Furthermore, at least one of the following optical path configuration options is included:

[0034] Option 1: Flexible optical fiber transmission path, using single / multimode optical fiber with a core of 50–600 μm and a transmission wavelength range of 300–2100 nm;

[0035] Option 2: Free-space optical path, transmission wavelength range 200–2000nm.

[0036] Furthermore, the laser used is selected from at least one of the following types: fiber laser, semiconductor laser, solid laser, CO2 laser.

[0037] Furthermore, the average output power of the laser ranges from 10W to 6000W.

[0038] Furthermore, the laser operates in a continuous mode or a pulse mode.

[0039] This invention discloses a method for collaborative surface machining using a five-axis linkage platform and a galvanometer based on spatial curve filling. This method uses spatial curves to fill a three-dimensional pattern, implementing a surface machining strategy that transitions from local laser scanning to global scanning. The method also synchronously generates the five-axis linkage platform's motion trajectory and galvanometer scanning instructions to achieve surface pattern machining. This invention has the following advantages:

[0040] 1. High-efficiency collaborative processing: Utilizing space-filling curves for continuous high-speed galvanometer scanning, the five-axis linkage platform performs overall workpiece position adjustment. This strategy significantly reduces idle travel and system waiting time in the laser scanning path, improving the overall processing efficiency of the five-axis linkage platform-galvanometer system.

[0041] 2. Highly consistent surface machining quality: Each machining point is strictly guaranteed to meet the dual process objectives of defocus distance constraints and laser incident angle constraints. This method effectively overcomes the impact of complex surface geometry on machining precision uniformity, ensuring that machining results (such as line width, depth, and topography) at any location on the surface meet highly consistent requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0043] Figure 1 : is flow chart of the present invention.

[0044] Figure 2 : A Hilbert space curve on a surface consisting of a continuous broken line segment.

[0045] Figure 3 : Hilbert space curve and its smooth path (Savitzky-Golay filter smoothing). DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to the embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0047] The device of the present invention is an existing laser processing device, mainly composed of a laser, a two-dimensional scanning galvanometer, and an XYZAC five-axis linkage CNC five-axis linkage platform. Invention Example 1: Precision surface microstructure etching (conformal mapping + Hilbert curve)

[0048] Technical scenario: Etch a cooling microhole array on the blade surface (STL model), with a pore diameter of ≤50μm, an incident angle requirement of θ≤30°, and a focal offset tolerance of ±0.05mm.

[0049] Execution steps:

[0050] (1) Parametric processing: Conformal mapping is performed on the blade surface to generate a UV plane map, preserving the angular relationship of the hole distribution;

[0051] (2) Spatial curve filling and optimization: The 7th-order Hilbert curve is used to fill the center points of all micropores and then smoothed using Savitzky-Golay filtering;

[0052] (3) 3D mapping and motion control: Mapping to a 3D surface, generating instructions for the five-axis linkage platform (AB swing head) and the galvanometer coordinated execution instructions. Iteratively check motion constraints and optimize.

[0053] (4) Execute processing, and match and execute corresponding micro-hole processing according to the execution status of the five-axis linkage platform instructions.

[0054] Invention Example 2: Car Dashboard Curved Surface Logo Engraving (Isometric Mapping + Z-Curve)

[0055] (1) Closed surface preprocessing: Split the instrument panel into two developable surfaces along the parting line;

[0056] (2) Efficient filling of Z-shaped curves: ARAP mapping is used to generate UV maps and Z-shaped curve filling patterns;

[0057] (3) Irregular pattern processing: After generating a rectangular filling domain covering the LOGO, the external points are cropped using the ray method;

[0058] (4) Hybrid axis five-axis linkage platform collaboration: Generate and iteratively check motion constraints, the turntable five-axis (AC axis) drives the workpiece to rotate, and the galvanometer completes the annular area scanning during the rotation period of the five-axis linkage platform;

[0059] (5) Effect: Continuous scanning without pause, no obvious splicing marks on the surface.

[0060] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A five-axis linkage platform-galvanometer collaborative surface processing method based on space curve filling, characterized in that: The following steps are involved: (1) Importing a 3D model, parameterizing it to obtain a 2D plane mapping, and moving the pattern to the target position in the 2D plane; (2) Fill the pattern with a spatial curve, smooth it, and obtain the motion trajectory of the five-axis linkage platform, which is then inversely mapped into three-dimensional space; (3) Calculate the laser incident angle and focal offset distance under the motion trajectory. If the restrictions are not met, modify the smoothing method, smooth again, and iterate until the requirements are met; (4) Generate the five-axis linkage platform and galvanometer motion instructions, check whether the speed, acceleration, jerk, etc. of each axis of the five-axis linkage platform meet the requirements, if not, smooth the local instructions, and iterate until the constraints are met; (5) Place the workpiece, perform processing and wait for processing to be completed.

2. The laser curved surface processing method according to claim 1, characterized in that: In step (1): If the target processing area is on a closed surface, it must be segmented first; The surface to be processed satisfies G 1 Curvature continuity condition; The parameterization methods include but are not limited to ARAP parameterization, conformal mapping, and isometric mapping; The three-dimensional model saves information in a triangular face format, including but not limited to stl and obj formats.

3. The laser curved surface processing method according to claim 1, wherein: In step (2): Space curves include but are not limited to Hilbert curves, Peano curves, Z-curves, etc. Set the curve order and scale to adjust the density of scan lines; For irregular patterns, first generate a spatial curve fill containing the pattern, and then remove the filling points outside the pattern; Smoothing methods include but are not limited to Gaussian smoothing, Savitzky-Golay filtering and other methods, which optimize regular broken line segments into continuous smooth curves.

4. The laser curved surface processing method according to claim 1, wherein: In step (5), the galvanometer scanning trajectory is generated as follows: each set of five-axis linkage platform instructions corresponds to the galvanometer scanning instruction, the movement of the five-axis linkage platform execution instruction is calculated, and the two-dimensional X and Y coordinates are saved as the galvanometer scanning trajectory.

5. The laser curved surface processing method according to claim 1, characterized in that: In step (6): It is necessary to determine the relative positions of the linkage platform coordinate system, the workpiece coordinate system, and the galvanometer coordinate system and perform coordinate transformation; A five-axis machining platform is used, the platform being a rotary table type, a swing head type or a hybrid structure, and its rotation axis configuration includes at least one combination of the following: a C axis around the Z axis and an A axis around the X axis; The C axis around the Z axis and the B axis around the Y axis; A axis around the X axis and B axis around the Y axis; The galvanometer system is configured as a two-dimensional scanning module or a three-dimensional galvanometer module with an integrated planar scanning component.

6. The laser curved surface processing method according to claims 1 to 5, characterized in that: Also includes at least one of the following optical path configuration options: Option 1: Flexible optical fiber transmission path, using single / multimode optical fiber with a core of 50–600 μm and a transmission wavelength range of 300–2100 nm; Option 2: Free-space optical path, transmission wavelength range 200–2000nm.

7. The laser curved surface processing method according to any one of claims 1 to 6, characterized in that: The laser is selected from at least one of the following types: fiber laser, semiconductor laser, solid laser, CO2 laser.

8. The laser curved surface processing method according to claim 7, characterized in that: The average output power of the laser ranges from 10W to 6000W.

9. The laser curved surface processing method according to claim 7, characterized in that: The laser operates in continuous mode or pulse mode.

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