A laser processing method based on scanning path control energy distribution

Abstract

The application provides a laser processing method based on scanning path control energy distribution, and relates to the technical field of laser processing, and specifically comprises the following steps: the method reconstructs a real-time hole shape containing a circumferential deviation by establishing an ideal hole shape model and layer-by-layer processing and acquiring a three-dimensional point cloud of a hole wall in real time; a radius deviation field and a taper deviation field are calculated according to the three-dimensional point cloud, a spiral eccentric scanning path is dynamically generated, and the incident angle of a light beam is adjusted according to the taper deviation; meanwhile, an equivalent deviation is obtained by combining the deviation field and the circumferential deviation and weighting, a single-pulse laser energy is dynamically adjusted through a reverse adjustment function, and a flat-top beam shaping is matched, so that precise energy distribution is realized. The method can effectively improve the size precision and taper consistency of a laser processed hole.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, specifically to a laser processing method based on scanning path control of energy distribution. Background Technology

[0002] In the field of laser micromachining, especially for the manufacture of high aspect ratio micro-holes or tapered holes, such as the film cooling holes in aero-engines and through-holes in medical implants, extremely high requirements are placed on hole shape accuracy. Traditional laser drilling methods mostly use a helical scanning path with fixed parameters and constant single-pulse energy for layer-by-layer ablation. The processing lacks the ability to perceive and dynamically control the three-dimensional morphology inside the hole in real time. Due to the thermal accumulation effect of materials, plasma shielding, uneven molten material discharge, and the nonlinear characteristics of beam-material interaction, local over-ablation or under-ablation is very likely to occur during actual processing. This results in significant circumferential non-uniformity of the hole wall and axial taper deviation from the target value, which seriously affects the hole shape quality and functional performance.

[0003] To improve taper control, existing technologies attempt to achieve tapered hole processing by adjusting the laser incident angle. For example, prior art publication CN119141036A discloses a micro-hole processing method that adjusts the laser incident angle in real time. This method experimentally fits the functional relationship between the incident angle and the taper, and gradually reduces the compensation incident angle layer by layer to eliminate positive taper. However, this method still relies on a preset path and open-loop energy control, without introducing online measurement and feedback of the actual hole shape, and cannot cope with dynamic deviations caused by changes in material state during processing. Another prior art publication CN114799572A proposes a laser cutting method based on scanning path-controlled energy distribution, which regulates energy deposition by shifting the beam position and adjusting the incident angle. However, it focuses on two-dimensional cutting scenarios and does not address the reconstruction and closed-loop correction of the three-dimensional hole wall morphology in deep hole processing. Furthermore, the prior art with publication number CN111496393A controls the taper of the group of holes by rotating the laser beam through an optical rotation system, while the prior art with publication number CN106312333A uses an off-axis device to generate a circular spot to improve the consistency of the aperture. Although these methods improve the processing effect in a specific dimension, none of them have established a closed-loop mechanism of "real-time morphology perception - deviation field calculation - path and energy coordinated control".

[0004] In summary, existing laser deep hole / taper hole machining technologies generally suffer from the following drawbacks: the scanning path is fixed and cannot be dynamically adapted to the actual three-dimensional morphology of the hole wall; the laser energy is constant or only coarsely adjusted, without fine energy distribution based on local radius deviations and circumferential inhomogeneities; although some solutions adjust the incident angle to control the taper, they lack real-time feedback and dynamic tilt correction mechanisms based on measured taper deviations; the overall machining process is open-loop or semi-closed-loop, making it difficult to effectively suppress cumulative errors caused by heat accumulation and material removal rate fluctuations. Therefore, there is an urgent need for a closed-loop laser machining method that integrates real-time three-dimensional morphology reconstruction, deviation field quantification analysis, conformal scanning path generation, and dynamic control of flat-top beam energy to achieve high-precision and highly consistent micro-taper hole manufacturing. Summary of the Invention

[0005] The purpose of this invention is to provide a laser processing method based on scanning path control of energy distribution to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A laser processing method based on scanning path control of energy distribution includes the following steps: S1: Establish an ideal hole shape model for the workpiece to be processed, determine the target hole diameter and target taper of the hole shape to be processed based on the ideal hole shape model, perform layered processing on the workpiece to be processed based on the target hole diameter and target taper, acquire the three-dimensional topography point cloud of the hole wall of the workpiece to be processed in real time during the processing, and reconstruct the real-time hole shape data including circumferential deviation based on the point cloud data. S2: Based on the real-time aperture data, extract the measured average radius of each depth layer; use the difference between the measured average radius and the target radius converted from the target aperture as the radius deviation; perform linear fitting on the measured average radius within a preset depth range, calculate the measured half-cone angle based on the fitting slope, and use the difference between the measured half-cone angle and the target taper as the taper deviation; the radius deviation and the taper deviation constitute a deviation field; S3: Based on the deviation field and circumferential deviation, dynamically generate an eccentric spiral conformal scanning path, and determine the beam incident tilt angle according to the taper deviation at the current processing depth and the measured half-cone angle in the real-time hole shape data; S4: Based on the deviation field and circumferential deviation at each point on the eccentric spiral conformal scanning path, the equivalent deviation is calculated by weighting, and the single-pulse laser energy is dynamically adjusted according to the equivalent deviation using a preset reverse adjustment function to control the beam to maintain a flat-top distribution within the spot area. S5: Perform layer-by-layer processing according to the eccentric spiral conformal scanning path and dynamically allocated laser energy. Repeat steps S2 to S4 after each layer is processed, and adjust the beam incident tilt angle in real time according to the current taper deviation until the processing is completed.

[0007] Furthermore, an ideal hole shape model of the workpiece to be processed is established, which describes the target hole diameter distribution and target taper along the hole depth direction; specifically, it includes: determining the coordinate system of the workpiece to be processed, with the geometric center of the upper surface of the workpiece to be processed as the origin, the hole depth direction perpendicular to the workpiece surface as the Z-axis, and the downward direction is defined as the positive direction.

[0008] Furthermore, real-time hole shape data including circumferential deviation is reconstructed based on the three-dimensional topographic point cloud of the hole wall. The specific process is as follows: starting from the current hole bottom position, scan layer by layer along the negative Z-axis with a preset depth layer step size. At each depth position, rotate around the hole wall circumferentially. Each rotation uses points at equal angular intervals as monitoring points, and records the radial distance, circumferential angle, and depth of each monitoring point. The specific formulas involved are as follows: in, For depth layer indexing, For monitoring point indexing, For the first The circumferential angle of each monitoring point This represents the total number of monitoring points on each floor. For the first Depth coordinates of each depth layer To preset the depth layer step size, This represents the current processing depth. The point cloud is processed by median filtering and spline interpolation, and the real-time aperture radius function is reconstructed based on the processed point cloud. The measured average radius and circumferential deviation at each depth layer are calculated using the following formula: in, For depth The measured average radius at that location, For the first The depth layer, the first The radial distance after filtering and interpolation at each monitoring point For depth ,angle Circumferential deviation at the location.

[0009] Furthermore, the specific logic for calculating the deviation field is as follows: For all monitoring points at each depth layer, the difference between the measured average radius and the target radius at the corresponding depth is calculated as the radius deviation, and the specific formula is: in, For depth Radius deviation at that point For depth The measured average radius at that location, Depth in the ideal aperture model The target radius at that location; Within a preset depth range, a linear fit is performed on the measured average radius, and the measured half-cone angle is calculated based on the fitting slope. The difference between the measured half-cone angle and the target cone angle is taken as the cone deviation. Specifically, within the depth range... Internal The slope of the fitted curve is denoted as . The calculation formula is: in, For the actual measured hole depth The semi-cone angle at that point, For depth The target taper at that location, The length of the fitting window; For depth Taper deviation at that point.

[0010] Furthermore, the specific method for dynamically generating the eccentric spiral conformal scanning path is as follows: obtain the current processing depth. Average radius deviation at and circumferential deviation function The sliding average eccentricity compensation amount of the circumferential deviation function within a preset angle range is calculated using the following formula: in, This is the moving average eccentricity compensation amount. The angle half-width of the moving average. For variables The circumferential deviation function; after superimposing the sliding average eccentricity compensation amount and the average radius deviation, it is superimposed to the target radius to generate the projection trajectory of the eccentric spiral conformal scanning path in the processing plane.

[0011] Furthermore, the pitch of the eccentric spiral conformal scanning path is dynamically adjusted according to the average radius deviation, wherein the pitch... satisfy: in, The initial pitch, The preset pitch adjustment coefficient is used. Current processing depth The average radius deviation at that location.

[0012] Furthermore, the method for determining the incident tilt angle of the beam is as follows: based on the measured taper angle and taper deviation at the current machining depth, calculate the tilt angle between the beam axis and the Z-axis, using the following formula: in, Current processing depth The incident angle of the beam at that point, Current processing depth The measured half-cone angle at that location, Current processing depth Taper deviation at the point, For the preset feedback coefficient, and The calculated incident angle of the beam is limited to ensure that it does not exceed the preset maximum angle and is not less than zero.

[0013] Furthermore, based on the deviation field and circumferential deviation at each point along the eccentric spiral conformal scanning path, the equivalent deviation is calculated using a weighted average, specifically as follows: Set scan time parameters This is used to describe the change of the eccentric spiral path over time, for the scan time parameter. The corresponding scan path point depth is , angle is Take the average radius deviation at that depth. and the circumferential deviation at that angle The equivalent deviation, determined by the weighted average of the radius deviation and circumferential deviation, satisfies: in, Scan time parameter The corresponding depth of the scan path point Radius deviation at that point Scan time parameter The corresponding depth of the scan path point Circumferential angle Circumferential deviation at the location, and As preset weights, and ; The single-pulse laser energy is dynamically adjusted based on a preset inverse adjustment function, specifically according to the following formula: in, Scan time parameter The laser single pulse energy corresponding to the scanning path point, The initial single pulse energy, To preset the energy regulation coefficient, Scan time parameter The corresponding depth of the scan path point The target radius; The calculated laser single pulse energy is subjected to upper and lower limit processing to ensure that the laser single pulse energy is between the preset minimum energy and the preset maximum energy.

[0014] Furthermore, to control the beam to maintain a flat-top distribution within the beam spot area, specifically: a beam shaper is used to convert the laser beam into a flat-top distribution, with the intensity distribution as follows: in, Scan time parameter The corresponding instantaneous laser power, The laser repetition frequency, Radial position of the light spot The light intensity at that location, The radial distance from a point within the light spot to the center of the light spot. The preset flat-top light spot radius; The power of each pulse is adjusted in real time by an acousto-optic modulator, and the flat-top shape distribution is maintained by changing the total power.

[0015] Compared with existing technologies, the advantages of this invention are: by synchronously mapping the three-dimensional topographic deviation field to the three physical degrees of freedom of scanning path geometry, beam spatial attitude, and energy spatiotemporal distribution, multi-dimensional collaborative closed-loop control is achieved. Experiments show that the radius deviation between the final processed hole shape and the ideal hole shape can be controlled within ±2μm, and the taper error is less than 0.1°. This represents an order of magnitude improvement in accuracy compared to the traditional fixed path + constant energy method, and significantly improves processing consistency. It is suitable for the precision manufacturing of deep holes / tapered holes in difficult-to-machine materials such as stainless steel. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall method flow of the present invention; Figure 2 This is a path energy regulation data diagram according to an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0018] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0019] Example: Please see Figures 1-2 The present invention provides a technical solution: A laser processing method based on scanning path control of energy distribution includes the following steps: S1: Establish an ideal hole shape model for the workpiece to be processed, determine the target hole diameter and target taper of the hole shape to be processed based on the ideal hole shape model, perform layered processing on the workpiece to be processed based on the target hole diameter and target taper, acquire the three-dimensional topography point cloud of the hole wall of the workpiece to be processed in real time during the processing, and reconstruct the real-time hole shape data including circumferential deviation based on the point cloud data. In this embodiment, an ideal hole shape model of the workpiece to be processed is established. This model describes the target hole diameter distribution and target taper along the hole depth direction. Specifically, it includes: determining the coordinate system of the workpiece to be processed, with the geometric center of the upper surface of the workpiece as the origin, the hole depth direction perpendicular to the workpiece surface as the Z-axis, and defining the downward direction as the positive direction. A target hole radius function is defined. and target half-cone angle function For cylindrical holes of equal diameter, , Let be the target radius, and be a fixed constant. For tapered holes, a linear taper form is adopted: ,in Where is the orifice radius. The target half-cone angle is (0 < α < 90°). This example uses a GH4169 nickel-based superalloy, a 1000μm thick workpiece, with a target hole type of single-tapered through hole, and a target half-cone angle... Orifice target radius Total target depth = 1000 μm The wavelength is constant, but the method applies to any ideal aperture shape. 1064nm, pulse width 10 ps, ​​repetition frequency 100kHz, initial single pulse energy for The beam pattern is a flat-top distribution, and the beam diameter is... for Scanning galvanometer system parameters: Maximum scanning speed Layer thickness The processing depth of each layer is: .

[0020] Initial eccentric spiral scan path parameters: starting radius Slightly smaller than the orifice radius; pitch is Number of spiral turns per layer Store the above parameters in the control system and set the current processing depth. Total target depth .

[0021] In this embodiment, the specific process of reconstructing real-time hole shape data including circumferential deviation based on the three-dimensional topographic point cloud of the hole wall is as follows: After each layer of processing is completed, a coaxial spectral confocal distance sensor is used to perform circumferential scanning measurement of the inner wall of the processed hole. This sensor is coaxial with the laser processing head and obtains three-dimensional point cloud data by measuring the radial distance at different positions along the hole depth direction. Specifically, the scanning proceeds layer by layer from the current hole bottom position along the negative Z-axis with a preset depth layer step size. In this embodiment, the preset depth layer step size is [value missing]. At each depth position, the device rotates circumferentially along the hole wall. Each rotation uses points spaced at equal angles as monitoring points. In this embodiment, the interval is 1 degree, resulting in 360 monitoring points. The radial distance, circumferential angle, and depth of each monitoring point are recorded. The specific formulas involved are as follows: in, For depth layer indexing, For monitoring point indexing, For the first The circumferential angle of each monitoring point This represents the total number of monitoring points collected per lap. For the first The depth of each depth layer To preset the depth layer step size, This represents the current processing depth. This determines the axial sampling resolution. Its selection must match the total depth of the hole and the required taper accuracy. The smaller the value, the finer the axial profile, providing more raw data points for subsequent taper fitting, but also the longer the measurement time.

[0022] Median filtering and spline interpolation were performed on the point cloud. A 3×3 two-dimensional median filtering window was used to process the original radial distance. Filtering is performed to remove outliers caused by processing splashes and measurement noise. The filtering formula is as follows: Using the filtered data as a reference, cubic spline interpolation is then used along the circumference to complete and densify the point cloud, eliminating contour discontinuities caused by sampling intervals, and finally obtaining the filtered and interpolated radial distance. Based on the processed point cloud, a real-time aperture radius function is reconstructed, and the measured average radius and circumferential deviation at each depth layer are calculated. The formulas used are as follows: in, For the first Each depth layer The measured average radius at a depth of [location] For the first The depth layer, the first Radial distance at each monitoring point for , Circumferential deviation at the location. Using the arithmetic mean is simple and efficient to calculate, and can well characterize the overall material removal level of the layer at this depth. It is the benchmark for judging whether the layer is "over-ablated" or "under-ablated". The original measurement data is decoupled into two independent features: overall deviation and local non-uniformity, which provides technical space for subsequent sub-strategy control of S3 and S4.

[0023] This step explicitly expresses the processing targets—aperture and taper—in analytical function form and unifies them with the benchmark for subsequent closed-loop feedback. Existing technologies often only set a fixed aperture or rely on offline CAD models, lacking a target radius function that continuously varies along the hole depth, leading to difficulties in taper control. A coaxial spectral confocal distance sensor is used, coaxial with the processing beam, allowing in-situ measurement without disassembling the workpiece, and is unaffected by changes in the hole's surface inclination angle or material reflectivity (the spectral confocal principle relies solely on the wavelength-distance relationship). Existing technologies often use structured light or laser triangulation, which are prone to shadowing or multiple reflection errors in deep holes. This solution defines… and This provides a precise mathematical benchmark for deviation calculation, enabling subsequent steps to determine the radius deviation. and taper deviation Quantifiable computation is the foundation for subsequent adaptive path and energy adjustment. Simultaneously, high-density 3D point clouds are acquired, and the true aperture function is reconstructed after filtering and interpolation. This provides high-fidelity input data for subsequent deviation calculations. Measurement accuracy can reach the sub-micron level.

[0024] S2: Based on the real-time aperture data, extract the measured average radius of each depth layer; take the difference between the measured average radius and the target radius converted from the target aperture as the radius deviation; perform linear fitting on the measured average radius within a preset depth range, calculate the measured half-cone angle based on the fitting slope, and take the difference between the measured half-cone angle and the target taper as the taper deviation. In this embodiment, the specific logic for calculating the deviation field is as follows: For all monitoring points at each depth layer, the difference between the measured average radius and the target radius at the corresponding depth is calculated as the radius deviation, where the target radius is half of the target aperture; the specific formula for calculating the radius deviation is: in, For depth Radius deviation at that point For the actual measured hole depth The measured average radius at that location, Depth in the ideal aperture model The target radius is set at a certain value; a positive value indicates that the current radius is too large, resulting in over-ablation; a negative value indicates that the radius is too small, resulting in under-ablation. By subtracting the target value from the measured value, the positive or negative sign clearly indicates the direction of the error, which can be directly used for subsequent reverse adjustment logic.

[0025] Within a preset depth range, a linear fit is performed on the measured average radius, and the measured half-cone angle is calculated based on the fitting slope. The difference between the measured half-cone angle and the target cone angle is taken as the cone deviation. Specifically, within the depth range... Internal The slope of the fitted curve is denoted as . The calculation formula is: in, For the actual measured hole depth The semi-cone angle at that point, For depth The target taper at that location, The length of the fitting window; For depth Taper deviation at; where The target semi-cone angle. This indicates that the actual taper is greater than the target, resulting in a steeper hole wall, and vice versa. Based on the geometric definition of a tapered hole, the slope obtained from statistical fitting is converted into a physically meaningful angle value. Choosing to perform linear fitting within a sliding window, rather than fitting the entire hole depth, is to obtain local taper information and adapt to complex hole shapes where the taper may vary with depth. In this embodiment, the length of the fitting window is determined based on the layered processing thickness. Depth measurement step size The accuracy of taper control needs to be comprehensively determined, taking into account both local taper recognition accuracy and noise suppression capability; in this embodiment, the layer thickness... Measuring step length To adapt to the local taper control requirements of high aspect ratio microholes, a value of 10 times the layer thickness is used, which is a conventional value for taper fitting in laser microhole processing in this field. Let z be the taper deviation at depth z. If the sliding window is too large, the calculated taper will be too smooth, losing sensitivity to abrupt changes in local shape and causing feedback lag; if the window is too small, the fitting results are easily affected by local measurement noise and fluctuate drastically, leading to instability in the control system.

[0026] Existing technologies mostly use the aperture error at a single moment as the feedback quantity, lacking a quantitative description of the spatial distribution and evolution trend of the error. The advantage of this step is that it not only calculates the discrete radius deviation... Furthermore, the taper deviation was quantified through sliding linear fitting. This elevates the aperture shape error from a one-dimensional aperture diameter to a two-dimensional profile description. Radius deviation reflects the total material removal at a certain depth, while taper deviation reflects the slope of the aperture wall as it changes with depth. This distinction allows subsequent control to compensate for the total material removal error using the helical path radius and correct the slope error using the beam tilt angle. In this embodiment, the measured and calculated data for five typical depth layers and four circumferential characteristic angles are shown in Table 1 below: Table 1: Experimental Data for Typical Depth Layers and Circumferential Feature Angles This table covers Five typical cross-sections at the full machining depth, with four circumferential characteristic angles selected for each cross-section, fully present the core outputs of steps S1 and S2 of this application's scheme. The data includes basic measured values ​​such as measured radial distance, target radius, and average radius of the depth layer, and synchronously outputs core control parameters such as circumferential deviation, radius deviation, measured half-cone angle, and taper deviation. This intuitively reflects the changing law of circumferential non-uniformity of the hole wall as the machining depth increases, verifying that this application's scheme can stably control the hole shape deviation at the micrometer level, providing a precise input benchmark for subsequent path and energy regulation.

[0027] S3: Based on the deviation field and circumferential deviation, dynamically generate an eccentric spiral conformal scanning path, and determine the beam incident tilt angle according to the taper deviation at the current processing depth and the measured half-cone angle in the real-time hole shape data; In this embodiment, the specific method for dynamically generating the eccentric spiral conformal scanning path is as follows: obtaining the current processing depth. Average radius deviation at and circumferential deviation function The sliding average eccentricity compensation amount of the circumferential deviation function within a preset angle range is calculated using the following formula: in, This is the moving average eccentricity compensation amount. The angle half-width of the moving average. For variables The circumferential deviation function; after superimposing the moving average compensation amount and the average radius deviation, the result is added to the target radius to generate the projection trajectory of the eccentric spiral conformal scanning path in the processing plane. In this embodiment, In discrete implementation, the current angle is taken. The average deviation within a 15° range before and after. The circumferential deviation is chosen by moving average instead of using the point directly to avoid drastic changes in the scanning path in the circumferential direction, which would result in uneven movement of the mechanical galvanometer and sharp edges on the hole wall after processing. This determines the stiffness of the path. The larger the value, the smoother the path, but the less responsive it is to sharp local deviations; conversely, the smaller the value, the better the following performance, but the path may be rugged, introducing high-frequency vibrations.

[0028] Generate the planar projection of the eccentric spiral path, and let the scan time parameter t be the total scan time from layer 0 to the depth layer. ,angle , This refers to the single-cycle scan time. It is equal to the quotient of pitch and axial scanning speed, and its planar coordinates are as follows: in, The axial scanning speed is... This refers to the single-cycle scan time. As the starting angle, That is, the average radius measured at the current depth. Provide a reference circle; plus Correct the average size of the entire circle; plus Corrects local elliptical or irregular shapes. Three layers are superimposed, with clear hierarchy, and solve the problems of size, average error, and shape error respectively.

[0029] In this embodiment, the pitch of the eccentric spiral conformal scanning path is dynamically adjusted according to the average radius deviation, wherein the pitch... satisfy: in, The initial pitch, The preset pitch adjustment coefficient is used. Current processing depth The average radius deviation at that location. In this embodiment, , Based on the laser removal threshold of the material to be processed, the spot diameter, and the thickness of the delamination, a comprehensive calibration is performed to adjust the sensitivity of the pitch to radius deviation; the value range is... In this embodiment This value ensures that the pitch decreases smoothly as the radius deviation increases, guaranteeing both deviation correction efficiency and preventing excessively dense scanning paths that could reduce processing efficiency; that is, the larger the absolute value of the radius deviation, the smaller the pitch, resulting in a denser scan. This, in turn, determines the axial scanning speed. ,in The scanning frequency per revolution is equal to the repetition frequency divided by the number of pulses per revolution. For simplicity, we take... ,Right now ;In this formula The larger the pitch, the more the aperture deviates from the target, requiring denser pulses (i.e., smaller pitch) to concentrate energy for correction. (Formula) This ensures that when the deviation is zero, the pitch is the preset reference value. When the deviation increases, the pitch decreases smoothly and will never be zero or negative. It is a preset pitch adjustment coefficient, which determines the sensitivity of the pitch to radius deviation; The larger the pitch, the more significant the change in pitch will be even with a small radius deviation, resulting in a strong adjustment effect.

[0030] In actual control, the galvanometer trajectory is generated by an interpolation algorithm; a three-dimensional path is generated, and the coordinates increase linearly with time. in To ensure that each layer is scanned at the exact depth. Let the number of spiral turns be It can be rounded up and then fine-tuned. .

[0031] In this embodiment, the method for determining the incident tilt angle of the beam is as follows: based on the measured taper angle and taper deviation at the current processing depth, the tilt angle between the beam axis and the Z-axis is calculated, and the specific formula is as follows: in, Current processing depth The incident angle of the beam at that point, Current processing depth The measured half-cone angle at that location, Current processing depth Taper deviation at the point, For the preset feedback coefficient, and The calculated incident angle of the beam is limited to ensure it does not exceed a preset maximum angle and is not less than zero. .like This solution uses a five-axis galvanometer machining head, whose internal tilting mirror has a maximum safe deflection angle of 30°. Exceeding this angle will cause optical path obstruction, spot distortion, and focus position shift. Furthermore, in deep hole machining, excessive tilt angles can easily lead to hole wall obstruction and ineffective energy delivery to the bottom of the hole. Therefore, the maximum tilt angle is limited to 30°. Then take 0; It is a typical "feedforward + feedback" design. It is a feedforward term that allows the beam to roughly follow the actual tilt angle of the aperture wall; This is a feedback correction term that gradually pulls the taper back to the target value using a scaling factor less than 1. This tilt angle is achieved through a biaxial deflector and remains constant during scanning, updated once per layer. The calculated beam incident tilt angle is limited to ensure it does not exceed the preset maximum tilt angle and is not less than zero. The generated scanning time parameters... The sequence at the corresponding scan path point and the corresponding beam tilt angle Send to the galvanometer controller at time intervals Interpolation.

[0032] Existing helical scanning paths are mostly concentric circles with fixed radii and pitches, which cannot handle circumferential non-uniformity and axial deviations of the aperture wall. The advantage of this step is that the generated eccentric conformal path no longer has a fixed radius, but is dynamically adjusted according to the circumferential deviation, achieving precise material removal compensation. Furthermore, not only is the path variable, but the pitch and beam tilt angle are also dynamically adjusted according to the deviation field. When the radius deviation is large, the pitch is reduced; when the taper deviation is large, the beam tilt angle is adjusted, achieving coordinated compensation in both the geometric path and beam attitude degrees of freedom.

[0033] S4: Based on the equivalent deviation determined by the deviation field and circumferential deviation weighting at the deviation point of the eccentric spiral conformal scanning path, a preset reverse adjustment function is used to dynamically adjust the single-pulse laser energy and control the beam to maintain a flat-top distribution within the spot area. In this embodiment, the equivalent deviation is calculated by weighting the deviation field and circumferential deviation at each point on the eccentric spiral conformal scanning path, specifically as follows: Set scan time parameters This is used to describe the change of the eccentric spiral path over time, for the scan time parameter. The corresponding scan path point depth is , angle is Take the average radius deviation at that depth. and the circumferential deviation at that angle The equivalent deviation, determined by the weighted average of the radius deviation and circumferential deviation, satisfies: in, Scan time parameter The corresponding depth of the scan path point Radius deviation at that point Scan time parameter The corresponding depth of the scan path point Circumferential angle Circumferential deviation at the location, and As preset weights, and ; In this embodiment, and The range of values ​​are respectively And satisfy This embodiment takes The rationale for this setting is as follows: the radius deviation reflects the overall size deviation of the hole shape and has a dominant impact on the functional performance of the hole, while the circumferential deviation reflects local non-uniformity. Therefore, the overall radius deviation is given a higher weight to prioritize the correction of the overall hole diameter error while taking into account the correction of local circumferential non-uniformity. The design philosophy is that aperture shape error stems from both overall over / underburning and local non-uniformity; therefore, energy decisions must consider both. Based on a preset inverse adjustment function, the single-pulse laser energy is dynamically adjusted, specifically according to the following formula: in, Scan time parameter The laser single pulse energy corresponding to the scanning path point, The initial single pulse energy, To preset the energy regulation coefficient, Scan time parameter The corresponding depth of the scan path point The target radius is determined by a combination of the laser ablation threshold of the material to be processed, the initial single pulse energy, and the deviation correction response speed. The value range is [2, 4]; in this embodiment This value ensures that the equivalent deviation and single-pulse energy are linearly and stably adjusted, providing sufficient deviation correction capability without causing energy oscillations or over / under-ablation of materials due to excessive adjustment. The calculated laser single-pulse energy is subjected to upper and lower limit processing to ensure it falls between a preset minimum and a preset maximum energy. The preset minimum / maximum energy is determined as follows: the minimum energy is determined by the single-pulse laser ablation threshold of GH4169 nickel-based superalloy; below this value, effective material removal is impossible. The maximum energy is determined by the laser's maximum safe output power and heat-affected zone limitation; exceeding this value will result in heat accumulation, recasting, and over-ablation. The value range is... , In this embodiment Therefore , . It is a linear inverse regulator. Its core design principle is: when... The aperture is too large; ,energy Decrease the ablation rate; conversely, increase the energy. The ratio normalization process ensures that the adjustment logic of holes of different sizes is consistent; It is an energy regulation gain. The larger the value, the more drastic the energy change caused by a unit deviation. The value is too small, resulting in slow correction speed; An excessively large value may cause drastic energy fluctuations, leading to system oscillations or instability in material removal. In this embodiment... , Scan time parameter At the corresponding depth of the corresponding scan path point The target radius; the calculated single-pulse energy is subjected to upper and lower limit processing to keep it between the preset minimum energy and the preset maximum energy: in, To preset the minimum energy, The preset maximum energy is used; in this embodiment, the maximum energy is taken as... , .

[0034] In this embodiment, controlling the laser beam to maintain a flat-top distribution within the beam spot area is specifically achieved by using a beam shaper to convert the laser beam into a flat-top distribution, with the following intensity distribution: in, Scan time parameter The corresponding instantaneous laser power, The laser repetition frequency, Radial position of the light spot The light intensity at that location, The radial distance from a point within the light spot to the center of the light spot. To preset the radius of the flat-top light spot, in this embodiment... Corresponding to the diameter of the flat-top light spot The size is consistent with the processing spot size; the power of each pulse is adjusted in real time by an acousto-optic modulator, and the flat-top shape distribution is maintained by changing the total power.

[0035] This embodiment is based on the measured aperture deviation data in Table 1, and strictly follows the scheme of this application to complete the scanning path planning and dynamic control of laser energy. The core calculation parameters are shown in Table 2 below: Table 2: Path Energy Regulation Parameters Please see Figure 2 By combining the processing depth and circumferential angles in Tables 2 and 1, the core execution parameters of steps S3 and S4 of this application are fully presented. The data includes key control indicators such as weighted equivalent deviation, theoretical and limited single-pulse laser energy, dynamic pitch, and beam incident tilt angle. It intuitively reflects the collaborative closed-loop control logic of this application based on real-time aperture deviation, which controls the scanning path geometry, beam spatial attitude, and energy spatiotemporal distribution. This verifies that the scheme can achieve precise matching between processing parameters and aperture deviation, providing a quantitative control basis for the layer-by-layer processing execution of step S5.

[0036] Existing technologies often employ constant pulse energy during processing, which cannot adapt to the varying energy requirements caused by changes in path and aperture shape. The advantage of this step lies in: precisely adjusting the energy down to a single pulse, corresponding one-to-one with the scanning path points, achieving fine distribution of energy in the spatial domain with variations in angle and in the temporal domain with variations in pulse. Equivalent deviation. Simultaneous consideration of both average radius deviation and circumferential deviation allows for a more comprehensive determination of the required energy compensation at a given point. Energy is intelligently reduced in over-ablation regions and appropriately increased in under-ablation regions to minimize thermal impact. The use of a flat-top beam ensures uniform energy deposition within the beam's effective range, avoiding unstable ablation caused by excessively high energy at the Gaussian beam center, and providing ideal optical field conditions for precise and controllable material removal.

[0037] S5: Perform layer-by-layer processing according to the scanning path and dynamically allocated laser energy. Repeat steps S2 to S4 after each layer is processed, and adjust the beam incident tilt angle in real time according to the current taper deviation until the processing is completed.

[0038] Specifically, S5.1 executes the current layer processing: Galvanometer scanning is initiated, moving along the path generated in step S4; simultaneously, the laser emits light according to the energy sequence of step S4. One layer depth is then processed. Then, immediately stop the axial feed.

[0039] S5.2 Update Status: , .

[0040] S5.3 Repeat step S1: Measure the processing area again to obtain a three-dimensional point cloud from the bottom of the hole to the opening of the hole; S5.4 Repeat step S2: Recalculate the radius deviation field and taper deviation field for all depths. Note that the new data overwrites the old data to achieve loop closure.

[0041] S5.5 Updates the beam incident tilt angle of the next layer based on the latest calculated taper deviation: Re-execute S4.6 to obtain... And adjust the tilting mirror.

[0042] S5.6 Repeat steps S4-S5: for the next layer (depth range) This generates new eccentric spiral paths and energy distribution schemes.

[0043] S5.7 Termination Judgment: If ( If the accuracy tolerance is met, the processing is complete, and the laser is turned off; otherwise, return to S5.1 to continue to the next layer.

[0044] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0045] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0046] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0047] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A laser processing method based on scanning path control of energy distribution, characterized in that, The specific steps include: S1: Establish an ideal hole shape model for the workpiece to be processed, determine the target hole diameter and target taper of the hole shape to be processed based on the ideal hole shape model, perform layered processing on the workpiece to be processed based on the target hole diameter and target taper, acquire the three-dimensional topography point cloud of the hole wall of the workpiece to be processed in real time during the processing, and reconstruct the real-time hole shape data including circumferential deviation based on the point cloud data. S2: Based on the real-time aperture data, extract the measured average radius of each depth layer; use the difference between the measured average radius and the target radius converted from the target aperture as the radius deviation; perform linear fitting on the measured average radius within a preset depth range, calculate the measured half-cone angle based on the fitting slope, and use the difference between the measured half-cone angle and the target taper as the taper deviation; the radius deviation and the taper deviation constitute a deviation field; S3: Based on the deviation field and circumferential deviation, dynamically generate an eccentric spiral conformal scanning path, and determine the beam incident tilt angle according to the taper deviation at the current processing depth and the measured half-cone angle in the real-time hole shape data; S4: Based on the deviation field and circumferential deviation at each point on the eccentric spiral conformal scanning path, the equivalent deviation is calculated by weighting, and the single-pulse laser energy is dynamically adjusted according to the equivalent deviation using a preset reverse adjustment function to control the beam to maintain a flat-top distribution within the spot area. S5: Perform layer-by-layer processing according to the eccentric spiral conformal scanning path and dynamically allocated laser energy. Repeat steps S2 to S4 after each layer is processed, and adjust the beam incident tilt angle in real time according to the current taper deviation until the processing is completed. Establish an ideal hole shape model for the workpiece to be processed. This model describes the target hole diameter distribution and target taper along the hole depth direction. Specifically, it includes: determining the coordinate system of the workpiece to be processed, with the geometric center of the upper surface of the workpiece as the origin, the hole depth direction perpendicular to the workpiece surface as the Z-axis, and specifying the downward direction as the positive direction. Real-time hole shape data, including circumferential deviation, is reconstructed based on the 3D topographic point cloud of the hole wall. The specific process is as follows: starting from the current hole bottom position, scan layer by layer along the negative Z-axis with a preset depth layer step size. At each depth position, rotate around the hole wall circumferentially. Each rotation uses points at equal angular intervals as monitoring points, and records the radial distance, circumferential angle, and depth of each monitoring point. The specific formulas involved are as follows: in, For depth layer indexing, For monitoring point index, For the first The circumferential angle of each monitoring point This represents the total number of monitoring points on each floor. For the first Depth coordinates of each depth layer To preset the depth layer step size, This represents the current processing depth. The point cloud is processed by median filtering and spline interpolation, and the real-time aperture radius function is reconstructed based on the processed point cloud. The measured average radius and circumferential deviation at each depth layer are calculated using the following formula: in, For depth The measured average radius at that location, For the first The depth layer, the first The radial distance after filtering and interpolation at each monitoring point For depth ,angle Circumferential deviation at the location.

2. The laser processing method based on scanning path control of energy distribution according to claim 1, characterized in that: The specific logic for calculating the deviation field is as follows: For all monitoring points at each depth layer, the difference between the measured average radius and the target radius at the corresponding depth is calculated as the radius deviation. The specific formula is as follows: in, For depth Radius deviation at that point For depth The measured average radius at that location, Depth in the ideal aperture model The target radius at that location; Within a preset depth range, a linear fit is performed on the measured average radius, and the measured half-cone angle is calculated based on the fitting slope. The difference between the measured half-cone angle and the target cone angle is taken as the cone deviation. Specifically, within the depth range... Internal The slope of the fitted curve is denoted as . The calculation formula is: in, For the actual measured hole depth The semi-cone angle at that point, For depth The target taper at that location, The length of the fitting window; For depth Taper deviation at that point.

3. A laser processing method based on scanning path control of energy distribution according to claim 1 or 2, characterized in that: The specific method for dynamically generating the eccentric spiral conformal scanning path is as follows: obtain the current processing depth. Average radius deviation at and circumferential deviation function The sliding average eccentricity compensation amount of the circumferential deviation function within a preset angle range is calculated using the following formula: in, This is the moving average eccentricity compensation amount. The angle half-width of the moving average. For variables The circumferential deviation function; after superimposing the sliding average eccentricity compensation amount and the average radius deviation, it is superimposed to the target radius to generate the projection trajectory of the eccentric spiral conformal scanning path in the processing plane.

4. The laser processing method based on scanning path control of energy distribution according to claim 3, characterized in that: The pitch of the eccentric spiral conformal scanning path is dynamically adjusted based on the average radius deviation, wherein the pitch... satisfy: in, The initial pitch, The preset pitch adjustment coefficient is used. Current processing depth The average radius deviation at that location.

5. The laser processing method based on scanning path control of energy distribution according to claim 1, characterized in that: The method for determining the incident tilt angle of the beam is as follows: Based on the measured taper angle and taper deviation at the current machining depth, calculate the tilt angle between the beam axis and the Z-axis. The specific formula is as follows: in, Current processing depth The incident angle of the beam at that point, Current processing depth The measured half-cone angle at that location, for Taper deviation, The preset feedback coefficient, and The calculated incident angle of the beam is limited to ensure that it does not exceed the preset maximum angle and is not less than zero.

6. The laser processing method based on scanning path control of energy distribution according to claim 1, characterized in that: Based on the deviation field and circumferential deviation at each point along the eccentric spiral conformal scanning path, the equivalent deviation is calculated using a weighted average, specifically as follows: Set scan time parameters This is used to describe the change of the eccentric spiral path over time, for the scan time parameter. The corresponding scan path point depth is , angle is Take the average radius deviation at that depth. and the circumferential deviation at that angle The equivalent deviation, determined by the weighted average of the radius deviation and circumferential deviation, satisfies: in, Scan time parameter The corresponding depth of the scan path point Radius deviation at that point Scan time parameter The corresponding depth of the scan path point Circumferential angle Circumferential deviation at the location, and For preset weights, and ; The single-pulse laser energy is dynamically adjusted based on a preset inverse adjustment function, specifically according to the following formula: in, Scan time parameter The laser single pulse energy corresponding to the scanning path point, The initial single pulse energy, To preset the energy regulation coefficient, Scan time parameter The corresponding depth of the scan path point The target radius; The calculated laser single pulse energy is subjected to upper and lower limit processing to ensure that the laser single pulse energy is between the preset minimum energy and the preset maximum energy.

7. The laser processing method based on scanning path control of energy distribution according to claim 1, characterized in that: To control the laser beam to maintain a flat-top distribution within the beam spot area, specifically: a beam shaper is used to convert the laser beam into a flat-top distribution, with the following intensity distribution: in, Scan time parameter The corresponding instantaneous laser power, The laser repetition frequency, Radial position of the light spot The light intensity at that location, The radial distance from a point within the light spot to the center of the light spot. The preset flat-top light spot radius; The power of each pulse is adjusted in real time by an acousto-optic modulator, and the flat-top shape distribution is maintained by changing the total power.

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