Thin-wall metal material thinning method

Abstract

The embodiment of the invention provides a thin-wall metal material thinning method which comprises the steps that 1, the laser spot interval and the feeding frequency are calculated according to laser scanning parameters, and the laser scanning parameters comprise the feeding interval; 2, the thin-wall metal material component is obtained, and a to-be-machined face of the thin-wall metal material component is subjected to laser scanning according to the light spot interval to form a plurality of first-round micropores which are arranged at intervals; according to the light spot spacing, the feeding spacing and the feeding times, multiple rounds of circulating laser scanning are conducted on the to-be-machined face in sequence so that gaps between the first round of micropores can be filled, and a thin-wall metal material component with a loose modified layer is obtained; and 3, the loose modified layer is removed, so that thinning of the thin-wall metal material component is achieved. According to the embodiment, the adverse effect of heat accumulation on the workpiece in the laser machining process can be reduced while the thin-wall metal material component is thinned, the deformation resistance of the ultra-thin workpiece is improved, and the surface flatness of the workpiece is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of laser-assisted processing technology, and in particular to a method for thinning thin-walled metal materials. Background Technology

[0002] With the rapid development of lightweighting and miniaturization in fields such as aerospace, precision instruments, and high-end electronic equipment, thin-walled metal materials have become the preferred materials for various core structural components due to their excellent mechanical properties and spatial adaptability. Processing them into ultra-thin thin-walled components has also become a core demand of the industry for thin-walled metal material processing. However, the high-precision thinning process of thin-walled metal materials has always faced multiple technical challenges in terms of efficiency, stress control, and surface integrity.

[0003] In existing technologies, thinning processing solutions for thin-walled metal materials are mainly divided into two categories, both of which have significant technical limitations: On the one hand, traditional mechanical grinding processes remove material through abrasive cutting. Although the operation method is direct, when processing thin-walled metal materials, the contact stress of the abrasive can easily cause elastic deformation, uneven thickness, or even direct breakage of the workpiece. It can also easily introduce microcracks, residual stress, and other processing damage on the material surface and subsurface. For some high-hardness thin-walled metal materials, there are also problems such as severe abrasive wear and low processing efficiency, making it difficult to guarantee the forming quality of ultra-thin thin-walled components; On the other hand, conventional laser... Laser-assisted thinning technology reduces the surface hardness of materials through laser modification to decrease grinding resistance. While this improves processing efficiency and reduces tool wear to some extent, the process often employs high-power, low-speed scanning and other high-heat-input methods. This can easily introduce huge residual stresses on the surface of thin-walled metal materials with poor rigidity, leading to severe macroscopic warping deformation of the workpiece. This makes it impossible to fix the workpiece using conventional methods such as vacuum adsorption for subsequent precision machining. If rigid fixing is used to forcibly suppress deformation, the process is too complicated, and secondary damage to the ultra-thin workpiece may occur during subsequent disassembly and cleaning. This makes the process highly dependent on auxiliary tooling.

[0004] Therefore, there is an urgent need for a low-stress, high-efficiency thinning method for thin-walled metal materials to solve the problems of low processing efficiency, poor workpiece forming quality, strong dependence on auxiliary tooling, and easy secondary damage of existing technologies, so as to meet the high-precision manufacturing needs of ultra-thin thin-walled metal components in high-end fields. Summary of the Invention

[0005] Therefore, in order to overcome at least some of the defects and deficiencies in the prior art, embodiments of the present invention provide a method for thinning thin-walled metal materials.

[0006] Specifically, this invention provides a method for thinning a thin-walled metal material, comprising: Step 1: calculating the laser spot spacing and the number of feeds based on laser scanning parameters, wherein the laser scanning parameters include the feed spacing; Step 2: obtaining a thin-walled metal material component, and performing laser scanning on the surface to be processed of the thin-walled metal material component according to the spot spacing to form multiple mutually spaced first-round microholes; performing multiple rounds of cyclic laser scanning on the surface to be processed according to the spot spacing, the feed spacing, and the number of feeds to fill the gaps between the first-round microholes and obtain a thin-walled metal material component with a porous modification layer; Step 3: removing the porous modification layer to achieve the thinning of the thin-walled metal material component.

[0007] In a specific embodiment of the present invention, the multi-round cyclic laser scanning in step 2 corresponds to the formation of multi-round micropores. Each round of micropores consists of multiple micropores spaced apart from each other. The multi-round micropores include micropores from the second round to the nth round. The second round micropores are offset relative to the first round micropores, and the nth round micropores are offset relative to the (n-1)th round micropores.

[0008] In a specific embodiment of the present invention, step 2 includes: dividing the surface to be processed of the thin-walled metal material component into multiple sub-regions, wherein the number of feeds includes multiple sub-feed times set for each of the multiple sub-regions; for each of the multiple sub-regions, laser scanning is performed according to the spot spacing to form mutually spaced first-round micro-holes, and the multiple-round cyclic laser scanning is performed sequentially according to the spot spacing, the feed spacing, the sub-feed times corresponding to each sub-region, and the boundary constraint conditions of the sub-regions to fill the gaps between the first-round micro-holes; after completing the scanning of all the sub-regions sequentially, the thin-walled metal material component with the porous modified layer is obtained.

[0009] In a specific embodiment of the present invention, the laser scanning parameters further include laser scanning speed, laser frequency and spot diameter, wherein the spot spacing is calculated by the laser scanning speed and the laser frequency, and the spot spacing d=v / f, where v is the laser scanning speed and f is the laser frequency.

[0010] In one specific embodiment of the present invention, the light spot spacing is greater than the light spot diameter; and / or, the light spot diameter is 0.02~0.1mm.

[0011] In one specific embodiment of the present invention, the number of laser feeds is determined by the ratio of the spot spacing to the feed spacing.

[0012] In a specific embodiment of the present invention, if the ratio of the spot spacing to the feed spacing is a positive integer, then the number of laser feeds is the ratio minus one; if the ratio is not an integer, then the number of laser feeds is the integer part of the ratio.

[0013] In one specific embodiment of the present invention, the laser scanning speed is 3000-8000 mm / s, the laser frequency is 20-80 kHz; and / or, the number of multiple rounds of cyclic laser scanning is 10-50 times; and / or, the laser wavelength of the laser scanning in step 2 is 1030-1080 nm, the pulse width is 10-200 ns, and the laser power is 2-12 W.

[0014] In one specific embodiment of the present invention, the feed spacing is smaller than the spot diameter; and / or, the feed spacing is 5 to 30 μm.

[0015] In a specific embodiment of the present invention, each micro-hole in the second to the nth round of micro-holes is offset relative to the previous round of micro-holes along the same laser feed direction, and the feed spacing corresponding to each round of scanning in the multi-round cyclic laser scanning is the same.

[0016] As can be seen from the above, the thin-walled metal material thinning method provided in this embodiment of the invention first performs laser scanning on the surface to be processed of the pre-processed thin-walled metal material component according to the spot spacing to form multiple mutually spaced first-round micro-holes. Then, combined with the spot spacing, feed spacing and feed number, multiple rounds of cyclic laser scanning are carried out to fill the gaps between the first-round micro-holes and form a loose modification layer. Finally, the loose modification layer is removed to complete the thinning of the thin-walled metal material component. This method can effectively reduce the heat accumulation during laser processing and reduce the adverse effects of heat accumulation on the workpiece. At the same time, the micro-hole stress release structure generated by laser-induced micro-holes breaks the continuity of residual stress on the workpiece surface, improves the deformation resistance of ultra-thin workpieces, ensures the flatness of the workpiece surface, and enables thin-walled metal material workpieces to maintain a flat state without the need for complex auxiliary tooling with rigid bonding, thus meeting the processing requirements of subsequent precision planar grinding. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic flowchart of a thin-walled metal material thinning method provided in an embodiment of the present invention.

[0019] Figure 2 Stress cloud diagram of laser scanning processed workpieces without micropore structure using existing technology.

[0020] Figure 3 This is a stress cloud diagram of the workpiece in the first round of laser scanning forming of microporous structures in an embodiment of the present invention.

[0021] Figure 4 This is a comparison curve of the macroscopic warpage evolution over time between the first round of microporous workpieces formed according to the embodiments of the present invention and the non-microporous workpieces in the prior art.

[0022] Figure 5 for Figure 1 A flowchart illustrating step 2.

[0023] Figure 6 for Figure 1 A flowchart illustrating step 3.

[0024] Figure 7 This is a comparison chart of the average material removal rates of different modified groups and unmodified groups in embodiments of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 described in the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0026] In the embodiments of this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0027] See Figure 1 This invention provides a method for thinning thin-walled metal materials. This method addresses the lightweight processing needs of ultra-thin metal components in the fields of aerospace, precision instruments, and high-end electronic equipment, and solves problems such as stress deformation, processing damage, and reliance on complex tooling in existing thinning processes.

[0028] The thinning method for thin-walled metal materials provided in this embodiment may include, for example, the following steps: S10, calculate the laser spot spacing and the number of feeds based on the laser scanning parameters, wherein the laser scanning parameters include the feed spacing; S20: Obtain a thin-walled metal material component; perform laser scanning on the surface to be processed of the thin-walled metal material component according to the spot spacing to form multiple mutually spaced first-round micro-holes; perform multiple rounds of cyclic laser scanning on the surface to be processed according to the spot spacing, the feed spacing and the number of feeds to fill the gaps between the first-round micro-holes and obtain a thin-walled metal material component with a loose modified layer. S30, remove the porous modified layer to achieve thinning of the thin-walled metal material component.

[0029] Specifically, before step S10, the thin-walled metal material undergoes pretreatment. This pretreatment is a preliminary process before laser processing, including removing burrs, oil, oxide scale, and other impurities from the sheet surface; trimming the sheet's dimensions; and eliminating edge defects. This results in a neatly shaped, clean thin-walled metal component, ensuring the initial flatness of the component surface meets standards and preventing surface impurities from affecting laser processing accuracy. After pretreatment, the qualified thin-walled metal component is placed stably at the processing station without the need for rigid bonding, mechanical clamping, or other complex auxiliary tooling. This simplifies the clamping process and avoids problems such as component deformation caused by tooling clamping stress.

[0030] In S10, based on the preset laser processing requirements, laser scanning parameters suitable for thin-walled metal materials are selected, and the laser spot spacing and feed count are accurately calculated accordingly. The spot spacing is used to limit the arrangement interval of the first round of micro-holes formed in S20, making them discretely spaced. The feed count is used to control the execution frequency of subsequent multi-round cyclic scanning, ensuring that the gaps between the micro-holes in the first round can be filled.

[0031] In S20, the entire surface of the thin-walled metal component to be processed is first scanned by laser according to the calculated spot spacing. Multiple spaced micro-holes are formed on the surface using laser thermal effect. This discretely spaced micro-hole arrangement is different from the single continuous scanning mode of the existing technology and is the key to achieving low-stress processing. Subsequently, the entire surface to be processed is scanned in multiple cycles by combining the spot spacing, feed spacing and predetermined feed number. The gaps between the micro-holes in the first round are gradually filled by the multi-round step scan. At the same time, the low-hardness loose modified layer is formed on the surface of the component by laser modification, which facilitates the subsequent removal process, avoids macroscopic warping deformation of the ultra-thin component and ensures the surface flatness of the component throughout the processing.

[0032] In S30, the thin-walled metal material component with a loose modified layer obtained in S20 is fixed, and then the loose modified layer on the surface is removed by grinding. Without high-intensity cutting, the modified layer can be accurately peeled off to achieve component thinning and reduce workpiece damage.

[0033] The thin-walled metal material thinning method provided in this embodiment utilizes a laser processing strategy that first forms a first round of spaced micropores, then sequentially scans and fills the gaps to form a porous modified layer. Combined with a subsequent porous modified layer removal process, this creates a low-stress thinning process system suitable for ultra-thin materials. This process relies on the discretely spaced micropore arrangement to physically isolate the heat generated during laser processing, effectively reducing heat accumulation and mitigating the adverse effects of thermal stress and the heat-affected zone. Simultaneously, the spaced micropores create a stress-relieving structure, breaking the continuity of residual stress on the workpiece surface. This effectively absorbs the phase transformation volume expansion stress during processing, significantly improving the deformation resistance of ultra-thin workpieces and ensuring that the workpiece maintains high flatness throughout the process even under non-rigid constraints. Subsequent processing can be carried out without the need for complex auxiliary tooling. Furthermore, the low-hardness porous modified layer formed by laser modification can be precisely peeled off through a grinding process. While achieving material thinning, this maximizes the protection of the workpiece substrate's integrity, avoids subsurface damage during processing, and fully preserves the material's mechanical properties and fatigue resistance.

[0034] Compared to traditional mechanical grinding thinning processes, this method avoids problems such as workpiece elastic deformation and uneven thickness caused by abrasive contact stress. It also effectively reduces processing damage such as surface and subsurface microcracks and residual stress, solving the industry pain points of severe abrasive wear and low processing efficiency in the processing of high-hardness thin-walled materials. This improves thinning efficiency while reducing processing costs. Compared to conventional laser-assisted thinning processes, this method abandons the high-heat input method of high-power, low-speed scanning. Through a controllable step-by-step scanning strategy, it avoids macroscopic warping deformation of the workpiece caused by high heat input, significantly reducing reliance on complex auxiliary tooling such as paraffin bonding and mechanical clamping. This simplifies the overall processing flow and avoids the risk of secondary damage to ultra-thin workpieces caused by complex tooling disassembly and cleaning. This method achieves efficient thinning of thin-walled metal materials while effectively ensuring the forming quality and surface integrity of ultra-thin thin-walled components, meeting the high-precision manufacturing requirements of ultra-thin thin-walled metal components in aerospace, precision instruments, and high-end electronic equipment industries.

[0035] Specifically, in S10, the laser scanning parameters include, for example, laser scanning speed, laser frequency, and spot diameter. The spot spacing is the center-to-center distance between two adjacent laser spots on the laser scanning path. The spot spacing is calculated using the laser scanning speed and the laser frequency, with the formula d = v / f, where v is the laser scanning speed and f is the laser frequency. This formula allows for the precise calculation of the appropriate spot spacing value based on the selected laser scanning speed and laser frequency, providing data support for the spacing arrangement of the microholes in the first round. This enables the first round of laser scanning to form regularly spaced discrete microholes on the surface to be processed, laying the foundation for reducing heat accumulation and forming a stress-relieving structure in subsequent processes.

[0036] In this embodiment, the laser scanning speed is selected as 3000-8000 mm / s, preferably 5000-6000 mm / s, and can be exemplarily selected as 3000 mm / s, 5000 mm / s, 5500 mm / s, 6000 mm / s, or 8000 mm / s. The laser scanning speed determines the duration of laser action on the material. If the scanning speed is too low, laser energy is prone to continuous accumulation on the material surface, causing thermal stress concentration, which in turn generates huge residual stress and damages the workpiece's processing flatness. The laser scanning speed parameters used in this embodiment can effectively control heat accumulation during processing and prevent macroscopic warping of ultra-thin metal material components. The laser frequency is 20-80 kHz, preferably 30 kHz-50 kHz, and can be exemplarily selected as 20 kHz, 30 kHz, 40 kHz, 50 kHz, or 80 kHz. The laser frequency must match the laser scanning speed, and the matching relationship between the two affects the spatial distribution of adjacent laser spots on the workpiece surface. The laser frequency parameter range set in this embodiment can work in conjunction with the selected laser scanning speed to form a reasonable spot spacing, so that the laser spots of a single round of laser scanning are discretely arranged on the workpiece surface and do not overlap with each other, avoiding the superposition of heat-affected zones and local heat accumulation within a single round of scanning, and preventing stress concentration and component deformation.

[0037] In this embodiment, the number of multiple-round cyclic laser scans is 10 to 50 times, preferably 15 to 25 times. Examples include 10, 15, 20, 25, and 50 scans. Taking a thin-walled metal material, titanium-based diamond composite material, as an example, if the number of scans is too few, the modified layer depth will be insufficient, failing to meet the subsequent grinding and thinning requirements. Furthermore, the diamond graphitization transformation will be incomplete, resulting in poor modified layer formation. If the number of scans is too many, it can easily cause the accumulation of heat during laser processing, leading to stress concentration. It can also cause the modified layer to become too deep, damaging the substrate and compromising the processing flatness of the ultra-thin thin-walled metal material component. The scan number parameter set in this embodiment aligns with the formation logic of the modified layer depth accumulating with the number of scans. Multiple-round cyclic scans can induce graphitization transformation and volume expansion of the diamond on the workpiece surface. The preferred number of scans, 15 to 25, can obtain a better modified layer thickness suitable for subsequent grinding requirements, balancing the modified layer formation effect and process controllability.

[0038] In this embodiment, the laser wavelength for laser scanning is 1030~1080nm, and 1030nm, 1055nm, 1064nm, or 1080nm can be selected for example. Taking the thin-walled metal material as a titanium-based diamond composite material as an example, this wavelength range is in the near-infrared band, which has a high absorption rate on the titanium alloy matrix of the titanium-based diamond composite material. This allows the laser energy to be efficiently coupled to the surface of the workpiece, and the surface diamond is precisely induced to undergo graphitization transformation through thermal effects, thereby forming a loose modified layer on the surface of the workpiece that is easy to remove by subsequent grinding. The pulse width is 10~200ns, preferably 50~100ns, and 10ns, 50ns, 75ns, 105ns, or 200ns can be selected for example. Taking the thin-walled metal material as a titanium-based diamond composite material as an example, the nanosecond-level pulse width is adapted to the modification characteristics of the material, which can accurately induce the surface diamond to undergo graphitization transformation without causing severe ablation of the material due to instantaneous energy release. The pulse width parameter range used in this embodiment enables the laser energy to be precisely applied to the modified area of ​​the workpiece surface, forming a loose modified layer on the surface that is easy to remove with subsequent grinding, while effectively protecting the structural integrity of the titanium-based diamond composite matrix and avoiding damage to the matrix due to laser action.

[0039] In this embodiment, the laser power is 2-12W, preferably 4-6W, and can be exemplarily selected as 2W, 4W, 5W, 6W, 7W, or 12W. If the laser power is too high, it will cause excessive heat input during processing, easily leading to thermal stress concentration and thus damaging the processing flatness of the thin-walled metal material component. The 4-6W low-power laser parameter set in this embodiment is suitable for the processing characteristics of ultra-thin thin-walled metal materials, and can stably output low-energy laser pulses, providing support for the subsequent multi-round low-energy pulse superposition to form an incubation effect, thereby obtaining a loose modified layer with controlled thickness and stable forming. In other embodiments, the laser scanning speed, frequency, laser wavelength, pulse width, and power can all be adapted and adjusted according to the specific material of the thin-walled metal material and the workpiece processing accuracy requirements, and are not limited here. Taking titanium-based diamond composite material as an example, the laser modification incubation effect of titanium-based diamond composite material in this embodiment refers to the process effect of using high-frequency, high-speed, and low-power laser parameters to gradually accumulate energy by cyclically superimposing multiple rounds of low-energy laser pulses on the surface of the material, gently inducing the graphitization transformation of the surface diamond, and at the same time causing the titanium matrix to form a loose structure, ultimately generating a loose modified layer composed of graphite phase and oxides on the surface of the workpiece.

[0040] In this embodiment, the spot spacing is greater than the spot diameter. This setting allows a single laser scan to create a physical isolation gap between the micro-holes formed on the surface to be processed, making the micro-holes independent modification points. This discrete distribution avoids the accumulation of processing heat in the horizontal direction, thereby suppressing the generation of macroscopic stress. In some embodiments, the spot diameter is 0.02~0.1mm, for example, 0.02mm, 0.06mm or 0.1mm can be selected. Preferably, the spot diameter is 0.05mm. This size is suitable for the processing requirements of ultra-thin thin-walled metal materials, which can ensure the effectiveness of micro-hole formation, provide a stable structural basis for subsequent stress release, and effectively control the range of the heat-affected zone of laser processing, avoiding workpiece deformation caused by the superposition of heat-affected zones due to excessively large spot size. In other embodiments, the spot diameter can also be adjusted according to the material of the thin-walled metal material, the actual processing thickness and size requirements of the workpiece, which is not limited here.

[0041] Specifically, the number of laser feeds is determined by the ratio of the spot spacing to the feed spacing. This number of feeds is used to match the feed amount of multiple rounds of cyclic laser scanning with the gap of the micro-hole in the first round, achieving gradual and orderly filling of the micro-hole gap. If the ratio of the spot spacing to the feed spacing is a positive integer, then the actual number of laser feeds is one less than that integer; if the ratio is not an integer, then the actual number of feeds is the integer part of the ratio. For example, if the spot spacing is 55 μm and the feed spacing is 20 μm, the theoretical ratio is 2.75, then the actual number of laser feeds can be 2. This aims to minimize heat accumulation during processing by controlling the physical overlap rate of the laser scanning path. Even after multiple rounds of laser scanning, tiny geometric gaps may remain between the micro-holes. However, due to the thermal diffusion effect during laser processing and the overlapping of adjacent heat-affected zones, the material at these gaps can still be induced to undergo porosity modification, ensuring that the micro-hole gaps are fully modified and filled, leaving no unmodified areas. It should be noted that in other embodiments, when the ratio of the spot spacing to the feed spacing is not an integer, the actual number of feeds can be the integer part of the ratio plus one. This rounding method is suitable for processing scenarios with relatively large workpiece thickness and low material thermal sensitivity. It can eliminate the risk of residual unmodified areas from the scanning path. An appropriate rounding method can be selected according to the actual material characteristics, thickness specifications, and processing accuracy requirements of the workpiece; no limitation is made here.

[0042] In some embodiments, the feed spacing is 5–30 μm, preferably 5–15 μm, and exemplary options include 5 μm, 10 μm, 15 μm, 17 μm, 18 μm, or 30 μm. The feed spacing parameters set in this embodiment can form an effective stress-blocking zone, breaking the continuous transmission of residual stress. Furthermore, the feed spacing must be smaller than the spot diameter so that through multiple feeds, the discrete spots in subsequent cycles gradually fill the gaps left by the previous scan, and the spots of adjacent laser scans form a moderate local overlap. This ensures uniform coverage of the loose modified layer on the workpiece surface and macroscopic continuity of the forming after multiple scans, while avoiding excessive overlap of spots causing the heat-affected zone to exceed limits. This further suppresses stress accumulation during processing and prevents stress concentration and deformation of ultra-thin thin-walled components caused by localized heat accumulation. The feed spacing parameters set in this embodiment are adapted to the processing characteristics of ultra-thin thin-walled metal materials, achieving both uniform coverage of the modified layer on the workpiece surface and effective suppression of stress accumulation during processing. In other embodiments, the feed interval can also be adapted and adjusted according to the actual value of the workpiece size, the spot diameter, and the workpiece's machining accuracy requirements, etc., which is not limited here.

[0043] In some embodiments of the present invention, the multi-round cyclic laser scanning corresponds to the formation of multi-round micropores. Each round of micropores consists of multiple spaced-apart micropores. The spacing arrangement of the micropores in each round is consistent with that of the first round of micropores, and is formed according to the spot spacing, so that the micropores in each round are physically isolated and discretely distributed. The multi-round micropores include second-round micropores to nth-round micropores. The second-round micropores are offset relative to the first-round micropores and fall within the gap region between the first-round micropores. The nth-round micropores are offset relative to the (n-1)th-round micropores and all fall within the gap region between the previous round micropores. Specifically, after the first round of laser scanning forms the first set of spaced micro-holes on the surface to be processed according to the spot spacing, each subsequent round of laser scanning moves the laser scanning position along the set laser feed direction and feed path, according to the feed interval, thereby forming the corresponding set of spaced micro-holes. After each round of micro-holes is formed, they maintain a mutually spaced distribution. Through such multiple feeds and round-by-round offset scanning, the micro-holes in subsequent rounds can cover the gaps between the micro-holes in previous rounds, gradually filling the gaps left by the previous scans. By using a multi-round discrete filling method, complete coverage of the surface to be processed of the thin-walled metal material component is achieved, ultimately forming a macroscopically continuous and microscopically porous loose modified layer on the surface of the component.

[0044] Furthermore, in each of the second to nth rounds of micro-holes, the micro-holes are offset relative to the previous round of micro-holes along the same laser feed direction. This offset distance is determined, for example, by a preset feed spacing, and the feed spacing corresponding to each round of scanning in the multi-round cyclic laser scanning is the same. By setting the offset along the same laser feed direction and with the same feed spacing round by round, it is possible to ensure that the offset amount of each round of scanning is uniform and controllable, the micro-hole gap filling process is orderly and stable, and the problems of missed scanning and repeated scanning caused by inconsistent offset direction or offset amount are avoided, thus ensuring the stable forming effect of the porous modified layer.

[0045] In some embodiments of the present invention, when performing the above-mentioned laser scanning processing, corresponding laser path planning is performed, specifically setting that the beginning and end scanning trajectories of the laser scan do not overlap. This ensures that during the scanning process of the surface to be processed, the laser beam can achieve sufficient laser scanning coverage of the edge area of ​​the workpiece, guaranteeing the formation of a uniform microporous structure and loose modified layer in the edge area, while effectively eliminating the stress concentration problem that easily occurs at the start and end points of the laser scan. This avoids micro-deformation of the ultra-thin workpiece caused by local stress concentration, further ensuring the overall processing flatness of the workpiece.

[0046] This invention employs a micro-hole forming method with intervals and offsets between each round. By adjusting the offset settings corresponding to the feed spacing, complete coverage of the surface to be processed is achieved. Simultaneously, relying on the interval arrangement of micro-holes in each round, heat accumulation during laser processing is continuously reduced, thermal stress concentration is avoided, and the stress release structure formed by the micro-holes is more uniformly distributed. This better absorbs the phase transformation volume expansion stress during processing, further improving the deformation resistance of ultra-thin workpieces and ensuring surface flatness during processing. At the same time, the porosity distribution of the resulting loose modified layer is regular. When the modified layer is subsequently removed by grinding, the grinding resistance is more uniform, which helps to reduce the wear of the grinding wheel and reduce subsurface damage generated during the grinding process.

[0047] To further verify the effect of the stress-blocking band formed by the first round of micropores in the embodiments of the present invention on the suppression of laser processing stress and macroscopic warpage, the present invention constructs simulation models of laser-scanned workpieces with existing technology without micropores and those with the first round of micropores formed in the embodiments of the present invention, and conducts simulation analysis. This yields stress cloud maps of laser-scanned workpieces with existing technology without micropores (hereinafter referred to as stress cloud maps without micropores, corresponding to Figure 2) and stress cloud maps of workpieces with laser scanning and first round of micropores formed in the embodiments of the present invention (hereinafter referred to as stress cloud maps with micropores, corresponding to Figure 3). Furthermore, a comparison curve of the macroscopic warpage evolution over time between the workpieces with the first round of micropores formed in the embodiments of the present invention and the workpieces without micropores in the existing technology is obtained. Figure 4 ).

[0048] The stress cloud diagram without pores shows that without the first round of micro-pores, a continuous and deep high-stress band forms on the top layer of the workpiece after laser scanning, and the thermal expansion stress propagates and accumulates unimpeded within the matrix. In the stress cloud diagram with pores, the first round of micro-pores physically truncates the high-stress band, resulting in a discrete distribution of high-stress areas, while the gaps between the micro-pores represent low-stress areas, successfully blocking the continuous transmission of stress. In the macroscopic warpage evolution curve, the blue line corresponds to laser scanning without the first round of micro-pores, and the green line corresponds to laser scanning with the first round of micro-pores. The curves show that the warpage displacement of the workpiece without the first round of micro-pores is higher throughout the process than that with the first round of micro-pores, and the final displacement value is also higher, proving that the first round of micro-pores can effectively reduce processing internal stress and suppress the amplitude of macroscopic warpage. It should be noted that this simulation is based on the first round of laser scanning, while actual processing includes multiple rounds of cyclic laser scanning. The stress and warpage control effects have a significant cumulative effect; therefore, the thin-walled metal material thinning method provided in this embodiment of the invention has a more significant actual suppression effect on macroscopic warpage and processing stress than the simulation results described above. Therefore, compared with the existing technology of continuous laser scanning process without micro-hole design, which is prone to serious stress accumulation and workpiece warping deformation, the embodiment of the present invention solves the technical pain points of thermal stress concentration and warping deformation in laser processing by forming a stress blocking zone through the first round of micro-holes, and realizes low-stress processing of ultra-thin thin-walled metal components.

[0049] Further, see Figure 5 S20 includes, for example: S21: Divide the surface to be processed of the thin-walled metal material component into multiple sub-regions, and the number of feeds includes multiple sub-feeds set for the multiple sub-regions; S22: For each of the multiple sub-regions, laser scanning is performed according to the spot spacing to form mutually spaced first-round micro-holes, and the multi-round cyclic laser scanning is performed sequentially according to the spot spacing, the feed spacing and the number of sub-feeds corresponding to each sub-region to fill the gap between the first-round micro-holes; S23: After scanning all sub-regions in succession, the thin-walled metal material component with the loose modified layer is obtained.

[0050] Specifically, in S21, the thin-walled metal material component can be divided into several geometric unit sub-regions according to the overall external dimensions of the surface to be processed. In some embodiments, the size of the sub-region is selected as 2mm×15mm, which is suitable for the laser scanning processing requirements of ultra-thin thin-walled components and can take into account both processing accuracy and scanning efficiency. In other embodiments, the division size of the sub-region can also be flexibly adjusted according to the actual processing specifications and accuracy requirements of the workpiece, which is not limited here.

[0051] To match the division of sub-regions, the number of feeds is also divided into multiple sub-feed counts, with each sub-region having a corresponding number of sub-feed counts. This ensures that the number of sub-feed counts matches the size and micropore gap filling requirements of the corresponding sub-region. At the same time, boundary constraints are set for the scanning feed of a single sub-region to ensure that the laser only acts within the range of that sub-region during processing, ensuring that the micropore gaps in each sub-region are fully filled and that the modified layer forming effect of each sub-region is stable.

[0052] In S22, laser scanning processing starts from the first sub-region at the edge of the surface to be processed of the thin-walled metal material component. For this sub-region, the first round of laser scanning is performed according to the calculated spot spacing to form multiple intermittent first-round micro-holes in the sub-region. Then, combining the spot spacing, feed spacing, the number of sub-feeds corresponding to the sub-region, and the boundary constraints of the sub-region, multiple rounds of cyclic laser scanning are carried out successively. The gaps between the first-round micro-holes in the sub-region are gradually filled by the round-by-round offset scanning method.

[0053] In this process, to ensure that the laser does not scan into other adjacent sub-regions during the processing of a single sub-region, the boundary constraint condition for the feed spacing is set as follows: when the cumulative offset of multiple rounds of cyclic laser scanning approaches the boundary of the current sub-region and the remaining offset distance is less than the preset feed spacing, the feed spacing of this scan is reduced according to the decreasing principle to ensure that the outer edge of the laser spot in this round strictly falls within the boundary of the current sub-region.

[0054] The number of cyclic scans within a single sub-region is, for example, 15 to 25 times. Through the aforementioned round-by-round offset scanning method constrained by boundary conditions, the gaps between the micro-holes in the first round within the sub-region are gradually filled. After completing the entire scanning process of the current sub-region, the laser beam moves to the next sub-region according to the set path and feed interval and repeats the laser processing operation of the previous sub-region on the next sub-region. The next sub-region is, for example, a sub-region adjacent to the current sub-region.

[0055] In S23, after all sub-regions have completed the above scanning process, the local loose modified layers formed by the processing of each sub-region are connected into a whole, and finally a loose modified layer with macroscopic continuity, microscopic porosity and uniform pore distribution is formed on the entire surface to be processed of the thin-walled metal material component, thereby obtaining a thin-walled metal material component with a loose modified layer.

[0056] The segmented scanning processing method provided in this invention achieves multiple low-stress optimization effects during the processing of ultra-thin, thin-walled metal materials through sub-region division and progressive laser scanning process design, combined with the incubation effect of multiple rounds of low-energy pulse superposition. This processing method can induce the formation of a macroscopically continuous, microscopically porous loose modified layer composed of graphite phase and oxides on the surface of the workpiece, while spontaneously generating a periodic microporous stress release structure to efficiently absorb the phase transformation volume expansion stress generated during processing. Furthermore, the tiny physical intervals formed between sub-regions act as stress-blocking zones, effectively cutting off the continuous accumulation of modified layer stress across the entire thin workpiece sheet, suppressing the superposition of macroscopic stress from a process layout perspective, thereby preventing warping deformation of ultra-thin workpieces. Simultaneously, the loose modified layer provides a processing foundation for subsequent grinding processes, reducing subsurface damage caused by uneven grinding resistance, better preserving the mechanical properties and fatigue resistance of the material matrix, and eliminating the need for complex auxiliary tooling throughout the processing. This simplifies the processing flow while reducing the risk of clamping and processing damage to ultra-thin workpieces.

[0057] Specifically, pre-processing the thin-walled metal material sheet includes, for example, laser cutting the thin-walled metal material sheet to obtain the thin-walled metal material component, and placing the thin-walled metal material component on a heat dissipation substrate.

[0058] Specifically, a laser beam is used to precisely cut thin-walled metal sheets. For example, the laser cutting uses the aforementioned laser parameters. After cutting, thin-walled metal components of a predetermined size can be obtained. In some embodiments, for example, the cutting is done into ultra-thin components with a thickness of 180μm and an external dimension of 15mm×15mm, which can ensure the cutting accuracy and shape regularity of the components. In other embodiments, the cutting size of the components can be adjusted according to actual processing requirements, which is not limited here.

[0059] Then, the laser-cut thin-walled metal material component is directly placed on the heat dissipation substrate. In some embodiments, the heat dissipation substrate is a metal heat dissipation substrate, utilizing the passive heat conduction effect of the metal heat sink to help control the overall heat accumulation during processing. Furthermore, the entire process does not require forced constraints such as paraffin bonding or mechanical clamping, avoiding the thermal shock damage and subsequent cleaning burden caused by traditional bonding processes. In other embodiments, the specific material and specifications of the heat dissipation substrate can be adjusted according to processing requirements; this is not limited here.

[0060] See Figure 6 Step S30 removes the porous modified layer to achieve thinning of the thin-walled metal material component, including: S31, the thin-walled metal material component with the porous modified layer is fixed, and the porous modified layer is removed by a low-load grinding process to achieve the thinning of the thin-walled metal material component.

[0061] Specifically, in step S31, since the thin-walled metal material component maintained good macroscopic flatness after laser scanning processing, it is fixed onto the grinding fixture. In some embodiments, the component can be fixed to the bearing plate of the grinding fixture by vacuum adsorption or temporary thin-layer bonding to ensure the positioning stability of the component during grinding and to avoid strong contact stress. In other embodiments, the fixing method of the component can be adjusted according to the type or specifications of the grinding equipment, which is not limited here. After the thin-walled metal material component is fixed, this embodiment uses a low-load precision grinding process to peel off the loose modified layer formed after laser modification in step S20, thereby achieving the thinning process of the thin-walled metal material component. In other embodiments, the process parameters of low-load grinding can be adjusted according to the thickness of the loose modified layer, which is not limited here.

[0062] In this embodiment of the invention, the thin-walled metal material component with a porous modified layer obtained by step S20 is fixed and the porous modified layer is removed by a low-load grinding process. This ensures the positioning accuracy of the grinding process and avoids secondary deformation of the component caused by strong contact stress. At the same time, the targeted removal of the porous modified layer reduces grinding resistance and grinding tool wear, effectively improves the thinning process efficiency, avoids damage to the component matrix by mechanical cutting forces, reduces subsurface damage, and retains the high strength and fatigue resistance of the thin-walled metal material to the greatest extent. Ultimately, it achieves a thinning effect without warping deformation of the workpiece, meeting the manufacturing requirements of precision thin-walled components in aerospace, precision instruments and other fields.

[0063] In this embodiment, titanium-based diamond composite material is selected as the thin-walled metal material. A thin-walled metal material component with a porous modified layer is obtained through the above method. The depth of the porous modified layer and the laser scanning parameters are related by a formula, which is as follows: X=735.28+303.46A-0.66634v-4.948C+40.456D-29.76A 2 +0.00006072v 2 +0.10344C 2 -0.9188D 2 Where X is the depth of the loose modified layer, A is the laser power, v is the laser scanning speed, C is the feed spacing, and D is the number of cycles of laser scanning.

[0064] The following section, in conjunction with Table 1, explains the relationship between the depth of the porous modified layer and the laser scanning parameters. Table 1 is as follows:

[0065] Table 1 It should be noted that the above correlation formula is a prediction model obtained by fitting multiple sets of process test data, used to characterize the quantitative correlation between the depth of the porous modified layer and the laser scanning parameters. Due to the limited number of test samples and the complex nonlinear characteristics of the material laser modification process, there are slight errors within the engineering tolerance range between the calculated values ​​of the formula and the measured modified layer depth data in Table 1.

[0066] In this embodiment of the invention, the depth of the loose modified layer is the vertical thickness of the loose modified layer formed on the surface of the thin-walled metal component after laser treatment. The depth of the loose modified layer is related to laser scanning parameters such as laser power, laser scanning speed, feed spacing, and number of multiple rounds of cyclic scanning. By precisely controlling the above laser scanning parameters, the depth of the modified layer can be controlled as needed, adapting to different thinning processing requirements of thin-walled metal components. This layer control design can strictly limit the modified area to the surface of the workpiece, effectively avoiding the problems of matrix damage caused by an excessively deep modified layer and insufficient modification caused by an excessively shallow modified layer. At the same time, it allows the modified layer depth to be precisely matched with the preset thinning thickness, and can also work in conjunction with the microporous stress release structure to reduce the phase transformation volume expansion stress. While achieving efficient thinning, it retains the mechanical properties of the matrix to the greatest extent, achieving the process effect of precise layer control modification.

[0067] This layer control design can adjust the modified layer depth to match the preset thinning thickness according to the actual thinning requirements of the workpiece, so that the modified layer, as a grinding sacrificial layer, precisely corresponds to the thinning requirements. At the same time, the depth that can be adjusted as needed can avoid damage to the substrate and a surge in stress caused by an excessively deep modified layer, and can also prevent insufficient removal of material by grinding due to an excessively shallow modified layer. It balances the thinning accuracy and the preservation of the mechanical properties of the substrate, and works in conjunction with the microporous structure to further suppress warping deformation.

[0068] To verify the effect of the loose modified layer formed by adjusting the laser scanning parameters of this invention on improving the grinding and thinning efficiency and processing stability of thin-walled metal materials, experimental groups 2 and 6 in Table 1 (loose modified layers formed by different combinations of laser scanning parameters) were selected and compared with the unmodified experimental group 0 in a comparative experiment with the same grinding time and other parameters. The grinding experiment table (Table 2) and the comparison chart of the average material removal rate of different modified groups were obtained. Figure 7 Table 2 is as follows:

[0069] Table 2 Experimental results show that the average material removal rates of experimental groups 2 and 6 of this invention are significantly higher than those of the unmodified experimental group 0. Specifically, the average material removal rate of experimental group 2 increased significantly from 0.533 μm / min in group 0 to 2.333 μm / min. This demonstrates superior process stability and controllability while achieving efficient grinding and thinning, making it an optimal parameter combination for thinning ultra-thin and thin-walled metal materials. The material removal rate is equal to the amount removed divided by the grinding time.

[0070] The above experimental results fully verify that the loose modified layer formed by precisely controlling laser scanning parameters such as laser power, scanning speed, feed spacing, and number of scans can effectively improve the material processing characteristics and significantly improve the grinding and thinning efficiency. Compared with the traditional unmodified grinding process, the process of the present invention achieves significant improvements in both processing efficiency and process stability, and can achieve precise thinning without high-intensity cutting, thus maximizing the protection of the integrity of the workpiece substrate.

[0071] Furthermore, it is understood that the foregoing embodiments are merely illustrative examples of the present invention. Provided that the technical features do not conflict, the structure is not contradictory, and the purpose of the invention is not violated, the technical solutions of the various embodiments can be arbitrarily combined and used.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for thinning thin-walled metal materials, characterized in that, include: Step 1: Calculate the laser spot spacing and the number of feeds based on the laser scanning parameters, including the feed spacing; Step 2: Obtain a thin-walled metal material component. Perform laser scanning on the surface to be processed of the thin-walled metal material component according to the spot spacing to form multiple mutually spaced first-round micro-holes. Perform multiple rounds of cyclic laser scanning on the surface to be processed according to the spot spacing, the feed spacing and the number of feeds to fill the gaps between the first-round micro-holes and obtain a thin-walled metal material component with a porous modified layer. Step 3: Remove the porous modified layer to achieve the thinning of the thin-walled metal material component.

2. The method for thinning thin-walled metal materials as described in claim 1, characterized in that, In step 2, the multi-round cyclic laser scanning corresponds to the formation of multi-round micropores. Each round of micropores consists of multiple micropores spaced apart from each other. The multi-round micropores include micropores from the second round to the nth round. The second round micropores are offset relative to the first round micropores, and the nth round micropores are offset relative to the (n-1)th round micropores.

3. The method for thinning thin-walled metal materials as described in claim 1, characterized in that, Step 2 includes: The surface to be processed of the thin-walled metal material component is divided into multiple sub-regions, and the number of feeds includes multiple sub-feeds set for each of the multiple sub-regions; For each of the multiple sub-regions, laser scanning is performed according to the spot spacing to form mutually spaced first-round micro-holes, and the multiple rounds of cyclic laser scanning are performed sequentially according to the spot spacing, the feed spacing, the number of sub-feeds corresponding to each sub-region, and the boundary constraint conditions of the sub-region to fill the gaps between the first-round micro-holes. After scanning all the sub-regions in succession, the thin-walled metal material component with the porous modified layer is obtained.

4. The method for thinning thin-walled metal materials as described in claim 1, characterized in that, The laser scanning parameters also include laser scanning speed, laser frequency, and spot diameter, wherein the spot spacing is calculated using the laser scanning speed and the laser frequency, and the spot spacing d=v / f, where v is the laser scanning speed and f is the laser frequency.

5. The method for thinning thin-walled metal materials as described in claim 4, characterized in that, The light spot spacing is greater than the light spot diameter; and / or, the light spot diameter is 0.02~0.1mm.

6. The method for thinning thin-walled metal materials as described in claim 5, characterized in that, The number of laser feeds is determined by the ratio of the spot spacing to the feed spacing.

7. The method for thinning thin-walled metal materials as described in claim 6, characterized in that, If the ratio of the spot spacing to the feed spacing is a positive integer, then the number of laser feeds is the ratio minus one; if the ratio is not an integer, then the number of laser feeds is the integer part of the ratio.

8. The method for thinning thin-walled metal materials as described in claim 6, characterized in that, The laser scanning speed is 3000-8000 mm / s, and the laser frequency is 20-80 kHz; and / or, the number of multiple rounds of cyclic laser scanning is 10-50 times; and / or, the laser wavelength of the laser scanning in step 2 is 1030-1080 nm, the pulse width is 10-200 ns, and the laser power is 2-12 W.

9. The method for thinning thin-walled metal materials as described in claim 6, characterized in that, The feed spacing is less than the spot diameter; and / or the feed spacing is 5 to 30 μm.

10. The method for thinning thin-walled metal materials as described in claim 2, characterized in that, Each micro-hole in the second to the nth round of micro-holes is offset relative to the previous round of micro-holes along the same laser feed direction, and the feed spacing corresponding to each round of scanning in the multi-round cyclic laser scanning is the same.

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