Laser processing method and system based on multi-time scale and space coupling control

Abstract

The application discloses a kind of based on multi-time scale and space coupling control's laser processing method and system, it is related to laser processing technical field.The method includes: determining processing parameter, including determining the first time interval between adjacent sub-pulses in envelope, determining the number of sub-pulses in each envelope according to target heat accumulation state, determining the second time interval between adjacent envelopes according to the cooling recovery time of processing area, and determining scanning speed according to envelope action frequency and single envelope material removal depth;According to processing parameter, generate laser pulse sequence;Coupling laser pulse sequence into liquid jet with pressure, and in liquid jet, total reflection transmission is carried out to the processing area of material to be processed to remove material, and the processing area is cooled during the period without laser action, and laser processing head and material to be processed are controlled relative motion according to scanning speed.The application can improve the processing efficiency of thick hard and brittle material while maintaining low thermal damage.

Description

Technical Field

[0001] This application relates to the field of laser processing technology, and in particular to a laser processing method and system based on multi-timescale and spatial coupling control. Background Technology

[0002] Currently, hard and brittle materials such as ceramics, neodymium iron boron magnets, and composite materials are widely used in industries such as aerospace, semiconductors, communications, and transportation. Many of these applications involve thick components, with some exceeding 40mm in thickness. These components operate under harsh conditions, demanding extremely high precision in machining, minimizing chipping and microcracks. However, the machining difficulty of hard and brittle materials increases dramatically once the thickness exceeds 10mm, typically requiring multi-step machining processes at the expense of efficiency and higher costs.

[0003] In related technologies, the processing methods for hard and brittle materials mainly include: conventional laser processing, which uses a high-energy-density laser beam to instantly melt or vaporize the material, is a thermal ablation process, and suffers from severe edge chipping when processing hard and brittle materials, as well as taper problems caused by the laser divergence angle; diamond wire saw cutting, which is a purely mechanical grinding process, with slow processing speed and high cost of diamond wire consumables, and is generally difficult to process hard and brittle materials larger than 20mm; abrasive waterjet cutting, which has a relatively slow processing speed and suffers from water pollution, abrasive residue, and taper problems; and ultrasonic-assisted machining, which has extremely low efficiency and expensive equipment. Liquid-guided laser processing transmits laser light flexibly through an optical fiber to a laser processing head, where it is coupled with a pressurized ultrapure liquid jet and ejected through a nozzle. The laser light is transmitted to the processing surface through total internal reflection within the liquid jet for processing. Compared to traditional dry laser processing, the non-laser interaction time within each processing pulse cycle continuously cools the material being processed, effectively reducing the thermal impact and improving processing quality. The cylindrical laser beam avoids the processing taper caused by the divergence angle. However, due to the cooling time included in each laser processing cycle, its processing speed is relatively slow and decreases significantly with increasing material thickness.

[0004] Therefore, existing liquid-guided laser processing suffers from at least the following problems: lack of thermal continuity between adjacent pulses, with each laser pulse acting approximately on a fully cooled material region, making it difficult for subsequent pulses to utilize the residual thermal state formed by the previous pulse; low thermal energy utilization, as the long pulse intervals prevent thermal damage, resulting in most of the processing cycle being spent in cooling, with a large amount of heat energy being carried away by the liquid jet before it participates in material removal; and discontinuous crack propagation, with material almost completely recovering between adjacent pulses, causing the stress field to re-establish itself, making it difficult for cracks to propagate continuously. These problems significantly limit the processing efficiency of liquid-guided laser processing, necessitating a liquid-guided laser processing method and system that can balance processing efficiency and quality. Summary of the Invention

[0005] The purpose of this application is to provide a laser processing method and system based on multi-timescale and spatial coupling control, which can effectively improve the processing efficiency of thick, hard and brittle materials, while maintaining processing quality.

[0006] To achieve the above objectives, this application provides the following solution:

[0007] In a first aspect, this application provides a laser processing method based on multi-timescale and spatial coupling control. The method includes: determining processing parameters, including: determining a first time interval between adjacent sub-pulses within an envelope; determining the number of sub-pulses within each envelope based on the target thermal accumulation state, so that a single envelope action forms a corresponding single-envelope material removal depth; determining a second time interval between adjacent envelopes based on the cooling recovery time of the processing area of ​​the material to be processed, so that the processing area is in a partially cooled state before the next envelope action, not having recovered to its initial temperature; determining a scanning speed based on the envelope action frequency and the single-envelope material removal depth; generating a laser pulse sequence according to the processing parameters, the laser pulse sequence including multiple envelopes, each envelope including multiple sub-pulses arranged according to the first time interval; coupling the laser pulse sequence into a pressurized liquid jet, and transmitting it through total internal reflection within the liquid jet to the processing area of ​​the material to be processed for material removal, wherein the liquid jet cools the processing area during periods without laser action, and controlling the laser processing head and the material to be processed to move relative to each other at the scanning speed for at least one pass of scanning processing.

[0008] Secondly, this application provides a laser processing system based on multi-timescale and spatial coupling control, including a control module, a laser source module, a liquid jet generation module, a laser processing head module, and a motion execution module; the control module is configured to determine processing parameters, including: determining a first time interval between adjacent sub-pulses within an envelope; determining the number of sub-pulses within each envelope based on the target thermal accumulation state, so that a single envelope action forms a corresponding single-envelope material removal depth; determining a second time interval between adjacent envelopes based on the cooling recovery time of the processing area of ​​the material to be processed, so that the processing area is in a partially cooled state before the next envelope action; and determining a scanning speed based on the envelope action frequency and the single-envelope material removal depth; The laser source module is used to generate a laser pulse sequence according to the determined processing parameters. The laser pulse sequence includes multiple envelopes, and each envelope includes multiple sub-pulses arranged according to the first time interval. The liquid jet generation module is used to generate a pressurized liquid jet. The laser processing head module is used to couple the laser pulse sequence into the pressurized liquid jet, so that the laser pulse sequence is transmitted through total internal reflection within the liquid jet to the processing area of ​​the material to be processed for material removal. The liquid jet cools the processing area during periods without laser action. The motion execution module includes a column, a worktable, and a bed, used to drive the laser processing head module and the material to be processed to move relative to each other at the scanning speed to perform at least one pass of scanning processing.

[0009] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0010] This application provides a liquid-guided laser processing method and system based on multi-timescale and spatial coupling control. By determining processing parameters, generating laser pulse sequences, and coupling processing execution, it achieves coordinated control of sub-pulse timescale, envelope timescale, inter-envelope recovery timescale, and spatial scanning scale. The determination of the first time interval and the number of sub-pulses allows the thermal effects of adjacent sub-pulses to accumulate in the processing area, with each envelope forming a corresponding single-envelope material removal depth. This changes the situation in conventional liquid-guided laser processing where each pulse acts independently and heat energy cannot accumulate. The second time interval is determined based on the cooling recovery time, ensuring the processing area is in a partially cooled state before the next envelope action. This avoids thermal damage caused by continuous heat accumulation while retaining some heat accumulation for subsequent envelopes, overcoming the efficiency bottleneck caused by complete cooling. The scanning speed is determined based on the envelope action frequency and the single-envelope material removal depth, allowing the same processing location to be continuously acted upon by multiple envelopes. The material removal depth accumulates spatially, allowing cracks to continue to propagate rather than re-initiating each time. Therefore, this application significantly improves the single-pass removal depth and processing efficiency of thick, hard, and brittle materials while maintaining the advantages of low thermal damage, high precision, and no taper. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the liquid-guided laser processing system provided in an embodiment of this application.

[0013] Figure 2 A flowchart of a liquid-guided laser processing method based on multi-timescale and spatial coupling control provided in an embodiment of this application.

[0014] Figure 3 This is a schematic diagram of the three-timescale structure of a laser pulse sequence provided in an embodiment of this application. Detailed Implementation

[0015] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 As shown, this embodiment provides a laser processing system based on multi-timescale and spatial coupling control, including a laser source module 100 (i.e., Figure 1 The laser module shown), liquid jet generation module 101, laser processing head module 102, motion execution module and control module 109 (i.e., Figure 1 The machining system shown includes CNC control and electrical control cabinet.

[0018] Laser source module 100 is used to provide the laser energy required for processing, including laser generating unit 111 ( Figure 1 The text appears to be a mix of seemingly unrelated fragments and incomplete sentences, making it impossible to translate accurately. It seems to be a collection of notes or snippets from various sources, possibly related to laser sources, laser transmission, and other technologies. Figure 1The laser unit 111 (labeled as fiber unit) includes a three-time-scale timing modulation unit 112, comprising an envelope sub-pulse time-scale adjustment sub-unit 112 / 1, an envelope sub-pulse quantity adjustment sub-unit 112 / 2, and an envelope interval time-scale adjustment sub-unit 112 / 3. The laser generation unit 111 can employ one or more combinations of solid-state lasers, fiber lasers, and disk lasers, such as pulsed solid-state lasers, pulse train mode lasers, and quasi-continuous modulation fiber lasers with adjustable repetition frequency. The three-time-scale timing modulation unit 112 can be integrated within the laser generation unit 111 or be an external, independent component used to modulate the time structure of the laser pulses. The laser transmission unit 113 uses optical fiber to flexibly transmit the modulated laser pulses to the laser processing head module 102.

[0019] The liquid jet generation module 101 includes an ultrapure water treatment unit 121 and a pressure generation and stabilization control unit 122. The ultrapure water treatment unit 121 is used to perform particulate filtration, ion chemical purification, and degassing on the water supplied by the water supply system. The pressure generation and stabilization control unit 122 includes a pressure pump and a regulating valve. The pressure pump can be driven by hydraulic, pneumatic, electric, or a combination thereof to generate and regulate water pressure. The pressure generation and stabilization control unit 122 is electrically connected to the control module 109, which monitors and stabilizes the pressure of the liquid jet in real time using a closed-loop system.

[0020] The laser processing head module 102 includes a laser beam guiding unit 131, a laser-liquid jet coupling unit 132, a nozzle 133, and a gas surrounding jet protection unit 134. The laser beam guiding unit 131 receives the laser pulse output from the laser source module 100. After collimation, reflection, and focusing by a lens group, a laser spot is formed at a specified depth of focus (i.e., the working distance, generally the upper surface of the nozzle 133). The alignment of the laser spot with the central axis of the upper surface of the nozzle 133 can be adjusted and fixed manually or electrically. A pressurized liquid jet enters the laser-liquid jet coupling unit 132 and couples with the laser. The coupled laser is ejected through the nozzle 133 along with the liquid jet. The nozzle 133 can be lined with a sapphire crystal to form a stable jet. Because the laser's incident angle satisfies the total internal reflection condition, the laser is repeatedly refracted and transmitted to the processing position within the liquid jet via total internal reflection. The gas surrounding jet protection unit 134 is located on the outer periphery of the nozzle 133 and uses a single gas or a mixture of gases to protect the stability of the jet. The gas mass flow rate is monitored by a mass flow meter.

[0021] The motion execution module includes a column 110, a worktable 107, and a bed 108. The laser processing head module 102 is mounted on the column 110 via a connecting structure 103 and can move along the Z direction. The workpiece 106 is placed on the worktable 107, which moves along the X and Y directions on the bed 108, thereby driving the laser processing head module 102 and the workpiece 106 to move relative to each other at a scanning speed v. The control module 109 is used to run and monitor the above system and to perform parameter determination and coordinated control in the following processing method.

[0022] like Figure 2 As shown, the liquid-guided laser processing method based on multi-timescale and spatial coupling control provided in this embodiment includes the following steps:

[0023] S21. Determine the processing parameters.

[0024] Specifically, this includes: determining the first time interval between adjacent sub-pulses within the envelope; determining the number of sub-pulses within each envelope based on the target thermal accumulation state, so that a single envelope action forms a corresponding single envelope material removal depth; determining the second time interval between adjacent envelopes based on the cooling recovery time of the processing area of ​​the material to be processed, so that the processing area is in a partially cooled state before the next envelope action, having not recovered to the initial temperature; and determining the scanning speed based on the envelope action frequency and the single envelope material removal depth.

[0025] S22. Generate a laser pulse sequence according to the processing parameters. The laser pulse sequence includes multiple envelopes, and each envelope includes multiple sub-pulses arranged according to a first time interval.

[0026] S23. The laser pulse sequence is coupled into the pressurized liquid jet and transmitted to the processing area of ​​the material to be processed by total internal reflection in the liquid jet for material removal. The liquid jet cools the processing area during the period without laser action, and controls the laser processing head and the material to be processed to move relative to each other at a scanning speed for at least one pass of scanning processing.

[0027] Figure 3 This is a schematic diagram of the three-timescale structure of the laser pulse sequence provided in the embodiments of this application. The following is in conjunction with... Figure 3 The process of determining the processing parameters is explained in detail. For example... Figure 3 As shown, the laser pulse sequence includes multiple envelopes, each envelope includes multiple sub-pulses arranged according to a first time interval, and there is a second time interval between adjacent envelopes.

[0028] Determine the first time interval between adjacent sub-pulses within the envelope. To ensure the thermal effect of adjacent sub-pulses accumulates in the processing area, the first time interval should be less than the local thermal relaxation time of the material to be processed. The local thermal relaxation time satisfies the following:

[0029] (1)

[0030] In the formula, For local thermal relaxation time, For effective heat-affected dimensions, Effective thermal diffusivity. Effective heat-affected zone. The size formed by the direct laser-affected area and the heat-affected area that persists above a preset thermal state threshold after the laser action ends can be obtained through at least one of the following methods: thermal conduction model calculation, numerical simulation (such as finite element thermal analysis), experimental measurement, and calibration of processing results. For example, it can be determined based on an engineering empirical formula according to the nozzle diameter. = (1.2~2.0)D estimation, where D is the diameter of the liquid jet; effective thermal diffusivity This can be obtained through material databases, processing temperature change models, or actual sample measurement data. Based on this, the first time interval satisfies:

[0031] (2)

[0032] In the formula, For the first time interval, This is a preset time scaling factor, 0 < <1, preferably 0.05≤ ≤0.5, at which point the sub-pulse thermal state remains at 60%~95%; Determined based on the target processing mode. The smaller the value, the higher the thermal state retained in the processing area when adjacent sub-pulses are applied.

[0033] The number of sub-pulses within each envelope is determined based on the target thermal accumulation state. Using the thermal state after the first sub-pulse as a baseline, the thermal state contribution of each sub-pulse is recursively accumulated according to the thermal state attenuation ratio to obtain the accumulated thermal state. The thermal state attenuation ratio satisfies:

[0034] (3)

[0035] The cumulative thermal state after the Nth sub-pulse satisfies:

[0036] (4)

[0037] The current envelope ends when the accumulated thermal state reaches a preset target proportion of the steady-state accumulated thermal state. The number of sub-pulses contained in the current envelope is the number of sub-pulses within the envelope, satisfying:

[0038] (5)

[0039] In the formula, r is the thermal decay ratio. This represents the cumulative thermal state after the Nth sub-pulse. This represents the number of sub-pulses within the envelope. The target heat accumulation coefficient for the envelope is the target proportion of the accumulated heat state at the end of the envelope to the steady-state accumulated heat state; 0 < <1, Determined based on the target processing mode, e is the natural constant, and ln is the natural logarithm. The material removal depth of a single envelope formed by the envelope effect satisfies:

[0040] (6)

[0041] In the formula, For single-envelope material removal depth, The effective thermally affected area (TWA) is the combined effective size of the area directly affected by the laser during a single envelope action and the TWA that persists above a preset thermal state threshold after the laser action ends. The preset depth coefficient is determined based on the target processing mode, such as high-quality mode. Use a value of 0.10~0.20, 0.20~0.35 in equilibrium mode, and 0.35~0.50 in high-efficiency mode. The effective heat-affected zone can be determined based on the diameter of the liquid jet.

[0042] (7)

[0043] In the formula, Here, is the size factor for the heat-affected zone, and D is the diameter of the liquid jet.

[0044] The second time interval between adjacent envelopes is determined based on the cooling recovery time of the processing area. Between adjacent envelopes, laser output is paused, and the liquid jet cools the processing area, allowing for partial thermal relaxation. The second time interval satisfies the following:

[0045] (8)

[0046] In the formula, For the second time interval, For cooldown recovery time, The cooling recovery coefficient is the ratio of the thermal state of the processing area at the start of the next envelope action to the thermal state at the end of the previous envelope action; 0 < <1, Determined based on the target processing mode, such as high-quality mode. Use 0.15~0.30 in balanced mode, 0.30~0.50 in high-efficiency mode, and 0.50~0.90 in high-efficiency mode. The smaller the value, the higher the degree of cooling recovery. The cooling recovery time is determined based on the heat exchange model:

[0047] (9)

[0048] In the formula, ρ is the density of the material to be processed, c is the specific heat capacity of the material to be processed, h is the convective heat transfer coefficient between the liquid jet and the material to be processed, A is the effective contact area of ​​the liquid, and V is the effective volume involved in cooling. The effective contact area of ​​the liquid is composed of the area of ​​the circular bottom surface of the laser action region and the area of ​​the semi-circular sidewall of the kerf:

[0049] (10)

[0050] The areas of the circular base and the semicircular sidewalls satisfy the following conditions:

[0051] (11)

[0052] (12)

[0053] The effective volume involved in cooling consists of a hemispherical volume with a diameter equal to the effective heat-affected zone and a semi-circular annular volume along one side of the scanning direction:

[0054] (13)

[0055] The volumes of the hemisphere and the semi-circular torus satisfy the following conditions:

[0056] (14)

[0057] (15)

[0058] In the formula, The area of ​​the circular base is Let the area be the side wall area of ​​the semicircle. For the volume of a hemisphere, Let be the volume of the semi-circular annulus, and D be the diameter of the liquid jet.

[0059] Determine the scanning speed. The envelope frequency is determined by the envelope duration and the second time interval. Since the displacement of the scanning motion within a single envelope cycle is much smaller than the effective diameter of the liquid jet, the same processing position is subjected to at least one envelope in a single pass. The cumulative material removal depth of each envelope forms the pass material removal depth. The number of envelopes experienced by the same processing position in a single pass satisfies the following condition:

[0060] (16)

[0061] The spatial overlap coefficient is defined as:

[0062] (17)

[0063] The scanning speed then satisfies:

[0064] (18)

[0065] In the formula, The envelope frequency, Depth of material removal for each pass. This refers to the number of envelopes received by the same processing position within a single pass. This is the spatial overlap coefficient. Let be the effective diameter of the liquid jet, and v be the scanning velocity. 0 < ≤1, The closer it is to 1, the fewer the number of envelopes the same processing position receives, and the higher the processing efficiency; The smaller the size, the higher the spatial overlap, the more stable the removal depth, and the better the surface quality, such as in high-quality mode. Take 0.1~0.2, 0.3~0.5 in balanced mode, and approach 1 in high-efficiency mode.

[0066] A laser pulse sequence is generated according to the processing parameters determined above. The laser source module 100 outputs sub-pulses within each envelope according to a first time interval, and outputs adjacent envelopes according to a second time interval, forming a sequence as follows: Figure 3 The laser pulse sequence shown has a three-timescale structure.

[0067] A laser pulse sequence is coupled into a pressurized liquid jet for processing. The laser pulse sequence is transmitted via optical fiber to the laser processing head module 102, where it is coupled with the pressurized liquid jet within the laser-liquid jet coupling unit 132. After being ejected through the nozzle 133, the laser pulse sequence undergoes total internal reflection within the liquid jet and is transmitted to the processing area of ​​the material to be processed for material removal. The liquid jet cools the processing area during periods without laser interaction. Simultaneously, the control module 109 controls the motion execution module to drive the laser processing head module 102 and the material to be processed to move relative to each other at a scanning speed v, performing at least one scan processing pass until the entire material thickness is processed.

[0068] During the processing: During a single envelope action, multiple sub-pulses act continuously on the same processing position. Since the first time interval is less than the local thermal relaxation time, the local temperature of the material does not completely decay. The thermal stress is superimposed under the action of multiple sub-pulses, forming a local stress state that exceeds the material crack initiation or propagation threshold, thus forming a single-envelope material removal depth. During the second time interval between adjacent envelopes, the liquid jet cools the processing area, and the material achieves partial thermal relaxation. The heat diffuses to the surroundings, inhibiting over-melting or uncontrolled crack propagation caused by continuous heat accumulation. At the same time, the temperature does not return to the initial temperature, retaining some heat accumulation for subsequent envelopes. At the scanning speed, the same processing position is sequentially subjected to multiple envelopes. The material removal depth of each envelope accumulates in space to form the pass material removal depth. The microcracks that have been formed continue to propagate under the action of subsequent sub-pulses and envelopes, rather than restarting each time as in conventional liquid-guided laser processing, thus significantly improving the single-pass processing depth. The entire material thickness is processed through multiple passes.

[0069] Furthermore, during the processing, at least one of the following can be adjusted according to the changes in processing depth and / or the switching of the target processing mode: the first time interval, the number of sub-pulses within the envelope, the second time interval, and the scanning speed. The control module 109 can also perform closed-loop optimization adjustment of the sub-pulse parameters, envelope parameters, envelope recovery parameters, and scanning speed parameters based on processing feedback information.

[0070] The target processing modes include high-quality mode, balanced mode and high-efficiency mode. Different target processing modes correspond to different envelope target heat accumulation coefficients and / or preset depth coefficients, as well as different cooling recovery coefficients and spatial overlap coefficients. By combining and adjusting the four-dimensional parameters, liquid-guided laser processing can be achieved under different materials, thicknesses and quality requirements.

[0071] The following example demonstrates parameter calculations under equilibrium mode, using the cutting and processing of 20mm thick silicon carbide ceramic. The values ​​below are for illustrative purposes only; actual processing should be calibrated based on material databases or sample measurement data: The diameter of the liquid jet is taken as D = 60μm; [Following...] =1.5D to obtain the effective heat-affected dimension =90μm; Effective thermal diffusivity of silicon carbide was obtained from a materials database. =60mm² / s, substituting into equation (1) yields the local thermal relaxation time. ≈33.8μs; take =0.2, from equation (2) we get the first time interval ≈6.8μs, from equation (3) the thermal state decay ratio r≈0.819; take =0.9, from equation (5) we can obtain the number of sub-pulses within the envelope. ≈12; take =2, from equation (7) we obtain the effective heat-affected zone size. =120μm, take =0.30, from equation (6) we get the single-envelope material removal depth =36μm.

[0072] From equations (11) and (12), the effective liquid contact area A ≈ 6.2 × 10⁻ 9 From equations (14) and (15), the effective volume involved in cooling is V≈6.1×10⁻¹³m³; taking the density of silicon carbide ρ=3210kg / m³, specific heat capacity c=700J / (kg·K), and the convective heat transfer coefficient h=1.0×10⁻¹³m³, we get m². 5 W / (m²·K), the cooling recovery time is obtained from equation (9). ≈2.2ms; take =0.4, from equation (8) we get the second time interval ≈2.0ms; the envelope duration is the product of the number of sub-pulses within the envelope and the first time interval, ≈81.6μs, then the envelope frequency... ≈480Hz; Set the material removal depth per pass =0.36mm, from equation (16) the number of envelopes received at the same processing position =10, from equation (17) we get =0.1, from equation (18) we get scanning speed v≈2.9mm / s; the 20mm thickness is processed in about 56 passes.

[0073] The method of this embodiment is applicable to metals, non-metals and composite materials, especially hard and brittle materials, such as silicon carbide, aluminum nitride, silicon nitride and other ceramic materials, semiconductor materials, neodymium iron boron and other magnetic materials, as well as ceramic matrix composites, carbon fiber composites, etc. For materials with different thermal properties, it is only necessary to redetermine the four-dimensional processing parameters according to the material thermal response parameters, without the need for a large number of repeated experiments.

[0074] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0075] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0076] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0077] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0078] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A laser processing method based on multi-time scale and space coupling control, characterized in that, The method includes: Determining processing parameters includes: determining a first time interval between adjacent sub-pulses within an envelope; determining the number of sub-pulses within each envelope based on the target thermal accumulation state, so that a single envelope action forms a corresponding single envelope material removal depth; determining a second time interval between adjacent envelopes based on the cooling recovery time of the processing area of ​​the material to be processed, so that the processing area is in a partially cooled state before the next envelope action, having not recovered to its initial temperature; and determining the scanning speed based on the envelope action frequency and the single envelope material removal depth. A laser pulse sequence is generated according to the processing parameters, the laser pulse sequence including multiple envelopes, each envelope including multiple sub-pulses arranged according to the first time interval; The laser pulse sequence is coupled into a pressurized liquid jet and transmitted via total internal reflection within the liquid jet to the processing area of ​​the material to be processed for material removal. The liquid jet cools the processing area during periods without laser action, and the laser processing head is controlled to move relative to the material to be processed at the scanning speed for at least one pass of scanning processing.

2. The liquid-guided laser processing method based on multi-timescale and spatial coupling control according to claim 1, characterized in that, The first time interval is less than the local thermal relaxation time of the material to be processed, so that the thermal effect of the adjacent sub-pulse accumulates in the processing area; the first time interval is the product of the local thermal relaxation time and a preset time ratio coefficient, the preset time ratio coefficient is less than 1 and is determined according to the target processing mode, the smaller the preset time ratio coefficient, the higher the thermal state retained in the processing area when the adjacent sub-pulse is applied.

3. The liquid-guided laser processing method based on multi-timescale and spatial coupling control according to claim 2, characterized in that, The local thermal relaxation time is the ratio of the square of the effective thermally affected size of the material to be processed to four times the effective thermal diffusivity; the effective thermally affected size is the size formed by the area directly affected by the laser and the area of ​​thermal effect that persists above the preset thermal state threshold after the laser action ends; the effective thermally affected size is obtained by at least one of the following methods: thermal conduction model calculation, numerical simulation, experimental measurement, and processing result calibration; the effective thermal diffusivity is obtained by a material database, a processing temperature change model, or actual sample measurement data.

4. The liquid-guided laser processing method based on multi-timescale and spatial coupling control according to claim 1, characterized in that, The number of sub-pulses within the envelope is determined as follows: Based on the thermal state after the first sub-pulse, the contribution of each sub-pulse to the thermal state is recursively accumulated according to the thermal state attenuation ratio to obtain the cumulative thermal state. The current envelope ends when the accumulated thermal state reaches a preset target proportion of the steady-state accumulated thermal state. The number of sub-pulses included in the current envelope is the same as the number of sub-pulses within the envelope, satisfying the following: Wherein, the thermal state decay ratio satisfies: In the formula, For the first time interval, Let e ​​be the local thermal relaxation time, e be the natural constant, and ln be the natural logarithm. The target heat accumulation coefficient is the proportion of the accumulated heat state at the end of the envelope to the target proportion of the steady-state accumulated heat state, where 0 < 0. <1, Determined based on the target processing mode.

5. The liquid-guided laser processing method based on multi-timescale and spatial coupling control according to claim 4, characterized in that, The single-envelope material removal depth is the product of the effective heat-affected zone size and the preset depth coefficient. The effective heat-affected zone size is the effective size formed by the area directly affected by the laser during the single-envelope action and the heat-affected zone that continues to exist above the preset thermal state threshold after the laser action ends. The preset depth coefficient is determined according to the target processing mode. The target processing mode includes high-quality mode, balanced mode and high-efficiency mode. Different target processing modes correspond to different envelope target heat accumulation coefficients and / or preset depth coefficients.

6. The liquid-guided laser processing method based on multi-timescale and spatial coupling control according to claim 1, characterized in that, The second time interval is determined based on the cooling recovery time and the cooling recovery coefficient, satisfying the following: In the formula, The second time interval, The cooling recovery time is... The cooling recovery coefficient is the ratio of the thermal state of the processing area at the start of the next envelope action to the thermal state at the end of the previous envelope action, where 0 < 0. <1, Based on the target processing mode, ln is the natural logarithm.

7. The liquid-guided laser processing method based on multi-timescale and spatial coupling control according to claim 6, characterized in that, The cooling recovery time is determined based on the heat exchange model and satisfies: The effective liquid contact area is formed by the area of ​​the circular bottom surface of the laser action region and the area of ​​the semi-circular sidewall of the kerf, satisfying the following: The area of ​​the circular base and the area of ​​the semicircular sidewall respectively satisfy: The effective volume involved in cooling consists of a hemispherical volume with a diameter equal to the effective thermally affected dimension and a semi-circular annular volume along one side of the scanning direction, satisfying: The volumes of the hemisphere and the semi-circular ring respectively satisfy the following: In the formula, ρ is the density of the material to be processed, c is the specific heat capacity of the material to be processed, h is the convective heat transfer coefficient between the liquid jet and the material to be processed, and D is the diameter of the liquid jet. The removal depth of the single-envelope material. The effective thermally affected size of the envelope is the effective size formed by the area directly affected by the laser during a single envelope action and the thermally affected area that continues to exist above a preset thermal state threshold after the laser action ends.

8. The liquid-guided laser processing method based on multi-timescale and spatial coupling control according to claim 1, characterized in that, The envelope frequency is determined by the envelope duration and the second time interval; the same processing position is subjected to at least one envelope in a single pass, and the material removal depth of each single envelope is accumulated to form the pass material removal depth; the number of envelopes received by the same processing position in a single pass is the ratio of the pass material removal depth to the single envelope material removal depth, and the scanning speed is the ratio of the product of the effective diameter of the liquid jet and the envelope frequency to the number of envelopes.

9. The liquid-guided laser processing method based on multi-timescale and spatial coupling control according to claim 1, characterized in that, During the processing, at least one of the following is adjusted according to the changes in processing depth and / or the switching of the target processing mode: the first time interval, the number of sub-pulses within the envelope, the second time interval, and the scanning speed.

10. A laser processing system based on multi-timescale and spatial coupling control, characterized in that, It includes a control module, a laser source module, a liquid jet generation module, a laser processing head module, and a motion execution module; The control module is configured to determine processing parameters, including: determining a first time interval between adjacent sub-pulses within an envelope; determining the number of sub-pulses within each envelope based on the target thermal accumulation state, so that a single envelope action forms a corresponding single envelope material removal depth; determining a second time interval between adjacent envelopes based on the cooling recovery time of the processing area of ​​the material to be processed, so that the processing area is in a partially cooled state before the next envelope action, having not recovered to its initial temperature; and determining a scanning speed based on the envelope action frequency and the single envelope material removal depth. The laser source module is used to generate a laser pulse sequence according to the determined processing parameters. The laser pulse sequence includes multiple envelopes, and each envelope includes multiple sub-pulses arranged according to the first time interval. The liquid jet generation module is used to generate pressurized liquid jets; The laser processing head module is used to couple the laser pulse sequence into the pressurized liquid jet, so that the laser pulse sequence is transmitted by total internal reflection within the liquid jet to the processing area of ​​the material to be processed for material removal, and the liquid jet cools the processing area during the absence of laser action; The motion execution module includes a column, a worktable, and a bed, used to drive the laser processing head module to move relative to the material to be processed at the scanning speed, so as to perform at least one pass of scanning processing.

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