Apparatus and method for water jet assisted blue laser beam

Abstract

The application relates to the technical field of laser precision machining, in particular to a water jet assisted blue light laser beam device and method thereof, which comprises the following: a blue light laser generating module for generating a laser beam with a wavelength of 450-470 nm; a water jet guiding module comprising a high-pressure water pump and a three-stage filtering device; a coaxial coupling machining head integrating an aspheric lens focusing system and a nozzle assembly; a dynamic regulation and control unit comprising a temperature sensor installed on the nozzle assembly and a pressure sensor at the outlet of the water pump; and an open heat management system connected with a machining area and a laser cooler cavity through a pipeline. Through the integration of the blue light laser generating module, the water jet guiding module, the coaxial coupling machining head, the dynamic regulation and control unit and the open heat management system, systematic innovation is realized, the 450-470 nm blue light laser is adopted, the absorption rate of high-reflective materials is improved, and the problem of low processing efficiency of traditional green light laser is solved.

Description

Technical Field

[0001] This invention relates to the field of laser precision machining technology, specifically to a device and method for a water jet-assisted blue laser beam. Background Technology

[0002] Waterjet-assisted laser processing technology couples a high-energy laser beam with a water jet, combining the high energy density of the laser with the cooling and scouring effect of the water flow to achieve high-precision processing with low thermal damage. It is widely used in aerospace, semiconductor, medical device and other fields, and has significant advantages, especially in the precision processing of hard and brittle materials and high-temperature alloys.

[0003] However, traditional technologies mainly revolve around 532nm green lasers, which have the following drawbacks when applied to highly reflective metallic materials such as copper and gold:

[0004] 1. Low absorption rate: The absorption rate of green laser on the surface of materials such as copper and gold is only 40%-60%, resulting in low processing efficiency. It requires high-power laser or multiple scans, which consumes a lot of energy and takes a long time.

[0005] 2. Insufficient thermal damage control: For heat-sensitive materials, traditional technologies have limited thermal management capabilities, which can easily lead to damage to material properties.

[0006] 3. The system is complex and has high maintenance costs. High-power lasers require an independent precision closed-loop water cooling system for heat dissipation. This system is large in size, occupies a lot of space, and has high maintenance costs.

[0007] 4. The nozzle is prone to ablation. Traditional green lasers have a high absorption rate in sapphire nozzle materials, which can easily cause thermal damage to the nozzle and shorten its lifespan.

[0008] Although blue lasers, due to their short wavelength characteristics, can enhance absorption rates on highly reflective metal and polymer surfaces, their application in waterjet-assisted processing is still in the exploratory stage, facing challenges such as coupling efficiency, heat dissipation, and system integration. Existing few technical solutions (such as a waterjet-assisted laser drilling device and its drilling process disclosed in patent CN116551218B and a waterjet-assisted laser processing system disclosed in CN209363853U) are not designed for blue laser wavelengths and cannot solve the aforementioned core problems. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a water jet-assisted blue laser beam device. By integrating a blue laser generating module, a water jet guiding module, a coaxial coupling processing head, a dynamic control unit, and an open thermal management system, it achieves systemic innovation. Employing 450-470nm blue laser, it improves the absorption rate of highly reflective materials and solves the problem of low processing efficiency in traditional green laser processing.

[0010] One embodiment of the present invention provides a device for water jet-assisted blue laser beam, comprising:

[0011] Blue laser generator module, used to generate laser beams with wavelengths of 450-470nm;

[0012] The water jet guiding module includes a high-pressure water pump and a three-stage filtration device;

[0013] Coaxially coupled machining head, integrating an aspherical lens focusing system and nozzle assembly;

[0014] The dynamic control unit includes a temperature sensor installed on the nozzle assembly and a pressure sensor at the water pump outlet;

[0015] An open thermal management system connects the processing area to the laser cooling chamber via pipelines.

[0016] In one embodiment, the nozzle assembly includes a mounting base and a sapphire nozzle, the inner wall of which is coated with a high-reflectivity film.

[0017] In one embodiment, the temperature sensor is an infrared thermometer, and the temperature sensor is embedded in the nozzle assembly mounting base.

[0018] In one embodiment, the dynamic control unit includes a PID controller configured to adjust the laser power and the water jet flow rate in a coordinated manner.

[0019] In one embodiment, the open thermal management system includes a spiral flow cooling chamber and a plate heat exchanger.

[0020] One embodiment of the present invention provides a water jet-assisted blue laser beam processing method based on the water jet-assisted blue laser beam device described in any of the above embodiments, comprising:

[0021] A laser beam is generated by the blue laser generating module and collimated and focused by an aspherical lens.

[0022] The water jet guiding module is driven to generate a high-pressure water jet;

[0023] The laser beam is guided into the water jet interface within the coaxial coupling processing head to achieve total internal reflection transmission.

[0024] The dynamic control unit monitors the processing temperature and adjusts the parameters accordingly.

[0025] The open thermal management system is used to recover wastewater to cool the laser.

[0026] In one embodiment, the linkage adjustment includes: increasing the water jet velocity and reducing the laser power when the temperature exceeds the limit.

[0027] In one embodiment, a high-reflectivity film is deposited on the inner wall of the sapphire nozzle before the laser beam is introduced.

[0028] In one embodiment, when cooling the laser, the incoming water is preheated by a plate heat exchanger.

[0029] In one embodiment, the position of the focusing lens is dynamically adjusted by an electric displacement stage so that the laser focus is positioned on the central axis of the water jet.

[0030] The device and method for water jet-assisted blue laser beam provided by the above technical solution have the following beneficial effects:

[0031] 1. Significantly improves the processing efficiency and quality of highly reflective materials. Utilizing the shorter wavelength of 450-470nm blue laser, the absorption rate of laser energy on the surface of highly reflective metal materials such as copper and gold is increased, achieving efficient material removal. Combined with the instant cooling and scouring effect of water jet, a high-quality processed surface with no splashes, no pores, and a minimal heat-affected zone can be obtained.

[0032] 2. The forced cooling effect of the water jet can rapidly reduce the temperature of the processing area, keeping thermal fluctuations within a very small range. Combined with the high energy absorption efficiency of blue lasers, processing can be completed with lower power, making it particularly suitable for precision micromachining of heat-sensitive materials such as medical vascular stents and biodegradable alloys.

[0033] 3. The water jet medium itself is purified and used to directly dissipate heat from the laser optical components, replacing the traditional independent closed water cooling unit. This eliminates the need for additional complex devices such as cooling towers and compressors, greatly simplifying the system structure, reducing equipment size, and lowering manufacturing and maintenance costs.

[0034] 4. In response to the characteristics of blue laser, a sapphire nozzle with a high-reflectivity film coated on the inner wall was designed. The high thermal conductivity of the high-reflectivity film can quickly dissipate heat, while its extremely low laser absorption rate can effectively resist laser ablation, thereby significantly extending the service life of the core vulnerable component nozzle and improving the long-term operational reliability of the entire system.

[0035] 5. By integrating multimodal sensors, such as infrared thermometers and pressure sensors, and intelligent control algorithms, such as PID controllers, the system can monitor the processing status in real time, such as temperature and pressure. Once an abnormality is detected (such as excessive temperature), the laser power and water jet parameters can be adjusted immediately to achieve adaptive processing, ensuring the stability and consistency of the processing effect.

[0036] 6. The open water circulation system realizes the recycling of water resources. At the same time, the waste heat generated by the laser during the processing is carried away by the water flow and can be recovered and reused through heat exchangers (such as preheating the inlet water), reducing energy waste. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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 the structures shown in these drawings without creative effort.

[0038] Figure 1 This is a diagram of the architecture of the present invention;

[0039] Figure 2 This is an architectural diagram of the water jet guiding module of the present invention;

[0040] Figure 3 This is a schematic diagram of the coaxial coupling processing head of the present invention;

[0041] Figure 4 This is an architectural diagram of the dynamic control unit of the present invention;

[0042] Figure 5 This is a schematic diagram of the fixed base and sapphire nozzle structure of the present invention;

[0043] Figure 6 This is a graph showing the absorption rate of water at different wavelengths according to the present invention.

[0044] Figure 7 This is a diagram of the overall structure of laser processing according to the present invention.

[0045] The markings in the diagram are explained as follows:

[0046] 100. Blue laser generator module;

[0047] 200. Water jet guidance module;

[0048] 210. High-pressure water pump; 220. Three-stage filtration device;

[0049] 300. Coaxial coupling machining head;

[0050] 310. Aspherical lens focusing system;

[0051] 320. Nozzle assembly; 321. Mounting base; 322. Sapphire nozzle;

[0052] 400. Dynamic control unit;

[0053] 410. Temperature sensor; 420. Pressure sensor; 430. PID controller;

[0054] 500. Open thermal management system. Detailed Implementation

[0055] The above detailed description is a specific description of feasible embodiments of the present invention. These embodiments are not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the so-called present invention should be included in the patent scope of this case.

[0056] Combination Figures 1 to 7 As shown, one embodiment of the present invention provides a device for a water jet-assisted blue laser beam, comprising:

[0057] Blue laser generator module 100 is used to generate laser beams with wavelengths of 450-470nm;

[0058] The water jet guiding module 200 includes a high-pressure water pump 210 and a three-stage filtration device 220;

[0059] The coaxially coupled machining head 300 integrates an aspherical lens focusing system 310 and a nozzle assembly 320.

[0060] The dynamic control unit 400 includes a temperature sensor 410 and a pressure sensor 420 installed at the water pump outlet, both mounted on the nozzle assembly 320.

[0061] The open thermal management system 500 connects the processing area and the laser cooling chamber via pipelines.

[0062] In this embodiment of the invention, a systematic innovation is achieved by integrating a blue laser generating module 100, a water jet guiding module 200, a coaxial coupling processing head 300, a dynamic control unit 400, and an open thermal management system 500. By using 450-470nm blue laser, the absorption rate of highly reflective materials (such as copper and gold) is improved, and the problem of low processing efficiency of traditional green laser is solved.

[0063] It should be noted that by simultaneously cooling the processing area and flushing away molten slag through water jets, the expansion of the heat-affected zone (HAZ) can be effectively suppressed, making it suitable for the precision machining of heat-sensitive materials, such as magnesium alloy vascular stents.

[0064] Furthermore, integrating laser generation, water-conducting coupling, dynamic control, and thermal management into a unified platform avoids the complexity of traditional multi-device collaboration and improves process stability and equipment reliability.

[0065] In one embodiment, the nozzle assembly 320 includes a fixed base 321 and a sapphire nozzle 322, the inner wall of which is coated with a high-reflectivity film.

[0066] In this embodiment of the invention, the high-reflectivity film has extremely high thermal conductivity and low laser absorption rate, effectively resisting the thermal shock of blue laser light and extending the nozzle life from hundreds of hours of traditional gemstone nozzles to more than 2,000 hours.

[0067] It should be noted that the coating reduces laser scattering and absorption losses on the inner wall of the nozzle, ensuring a coupling efficiency of ≥92% and improving energy utilization.

[0068] In one embodiment, the temperature sensor 410 is an infrared thermometer, and the temperature sensor 410 is embedded in the nozzle assembly 320 fixing base 321.

[0069] The dynamic control unit 400 includes a PID controller 430, which is configured to adjust the laser power and the water jet flow rate in a linked manner.

[0070] In this embodiment of the invention, based on real-time feedback from an infrared thermometer, the PID controller 430 responds to temperature changes within 10ms and controls the temperature fluctuation in the processing area within ±5℃ through a compensation strategy of "increased flow rate and reduced power".

[0071] It should be noted that the parameter combinations are automatically adjusted for different materials (such as copper and magnesium alloys) to avoid reliance on human experience and ensure processing consistency.

[0072] Furthermore, the argon protective layer isolates water mist and air from interfering with the laser beam, reducing energy loss by more than 3%, and the inert gas environment prevents material oxidation in the high-temperature processing zone, making it particularly suitable for high-quality surface treatment of active metals (such as titanium and magnesium alloys).

[0073] In one embodiment, the open thermal management system 500 includes a spiral flow cooling chamber and a plate heat exchanger.

[0074] In this embodiment of the invention, the titanium alloy plate heat exchanger transfers the heat of 60°C wastewater to the inlet end, achieving a heat recovery efficiency of greater than or equal to 70% and saving more than 15% of energy.

[0075] It should be noted that the processing wastewater directly cools the laser, eliminating the need for a separate cooling tower and saving 80% of water.

[0076] One embodiment of the present invention provides a water jet-assisted blue laser beam processing method based on the water jet-assisted blue laser beam device described in any of the above embodiments, comprising:

[0077] A laser beam is generated by the blue laser generating module 100 and collimated and focused by an aspherical lens.

[0078] The water jet guiding module 200 is driven to generate a high-pressure water jet;

[0079] The laser beam is guided into the water jet interface within the coaxial coupling processing head 300 to achieve total internal reflection transmission.

[0080] The dynamic control unit 400 monitors the processing temperature and adjusts the parameters accordingly.

[0081] The open thermal management system 500 is used to recover wastewater to cool the laser.

[0082] In this embodiment of the invention, the entire process is closed-loop controlled, covering the complete chain of laser generation → water jet coupling → dynamic processing → heat recovery, achieving the triple goals of "high-efficiency processing, low damage and green heat dissipation". The method steps and device modules are strictly correlated, such as the linkage of the execution parameters of the dynamic control unit 400, to ensure the consistency of processing effects between different devices, which is suitable for large-scale production.

[0083] In one embodiment, the linkage adjustment includes: increasing the water jet velocity and reducing the laser power when the temperature exceeds the limit.

[0084] In this embodiment of the invention, gradient compensation prevents over-adjustment: the rule of "flow rate +10% + power -5%" avoids sudden parameter changes that could cause processing interruptions and ensure process continuity.

[0085] It should be noted that for materials such as magnesium alloys, the depth of the heat-affected zone is pressed to less than 5μm to meet the stringent requirements of biomedical devices.

[0086] In one embodiment, a high-reflectivity film is deposited on the inner wall of the sapphire nozzle 322 before the laser beam is introduced.

[0087] In this embodiment of the invention, a high-reflectivity film can be added to the existing sapphire nozzle 322 by chemical vapor deposition (CVD) to reduce the modification cost. After coating, the nozzle has a high temperature resistance of more than 1000 degrees Celsius, which is suitable for long-term operation of high-power blue laser.

[0088] In one embodiment, when cooling the laser, the incoming water is preheated by a plate heat exchanger.

[0089] In this embodiment of the invention, the wastewater is preheated with heat to reduce the energy input required for laser cooling, which is in line with the concept of green manufacturing. After preheating, the temperature fluctuation range of the inlet water is -0.5°C to +0.5°C, ensuring the stability of the laser wavelength (drift range of -1 nm to +1 nm).

[0090] In one embodiment, the position of the focusing lens is dynamically adjusted by an electric displacement stage so that the laser focus is positioned on the central axis of the water jet.

[0091] In this embodiment of the invention, the focal length is adjusted by the Z-axis to adapt to different depth requirements of 0.1-10mm, and the spot position deviation range is -2μm to +2μm, ensuring that the laser energy is accurately applied to the central axis of the water jet and avoiding coupling failure.

[0092] It should be noted that this invention is applicable to the fabrication of micro- and nano-structures of highly reflective metallic materials (such as copper and gold) and heat-sensitive materials (such as biodegradable magnesium alloys). Through technologies such as blue light wavelength optimization, water jet confinement heat dissipation, and dynamic parameter control, it solves the core problems of low absorption rate, uncontrollable thermal damage, and nozzle ablation in traditional green light water-guided laser processing.

[0093] Traditional waterjet-assisted laser processing technology mainly uses 532nm green lasers, but it suffers from low absorption rate (40%-60%) and high energy consumption when processing highly reflective metals such as copper and gold. In addition, traditional technology has insufficient control over thermal damage to heat-sensitive materials (such as biodegradable magnesium alloys), and the nozzle is prone to ablation due to overheating caused by laser absorption.

[0094] The overall system architecture is as follows Figure 6 As shown, Figure 6 The graph shows the absorption rate of water to different wavelengths of light. As can be seen from the graph, the lowest absorption range is between 450nm and 550nm. This indicates that the total internal reflection capabilities of the green laser beam and the blue laser beam for water layer confinement are similar. Therefore, blue light water-guided laser processing is theoretically feasible. Moreover, the coupling efficiency of blue light is also similar to that of green light.

[0095] Furthermore, the workflow of the open thermal management system 500 is as follows:

[0096] First, the blue laser is shaped and focused into the water jet, forming a coaxial transmission of "laser-water beam" through the total internal reflection interface; then, the high-pressure water jet (20-300μm diameter) carries the laser energy to impact the workpiece surface, simultaneously cooling the processing area and washing away the molten slag.

[0097] Secondly, the sensor monitors the processing parameters (temperature, pressure, flow rate) in real time and dynamically adjusts the laser power and water jet state;

[0098] Finally, the heat dissipation pipes are opened to recover heat and maintain the long-term stable operation of the system;

[0099] Key component descriptions:

[0100] 1. The dynamic control unit 400 of the blue laser generation module 100 adopts:

[0101] Laser diode array: using GaN (gallium nitride) based semiconductor material, output wavelength 450-470nm, power adjustable from 1-2kW;

[0102] Wavelength stabilization module: Through FBG (fiber Bragg grating) feedback control, it ensures that the wavelength drift is less than ±1nm;

[0103] Optical lens group: composed of aspherical lenses and plane emitters, which propagate and focus the light beam, with a beam quality M² less than 1.3;

[0104] 2. Water jet guidance and coupling system, Figure 3 Cross-sectional view of water jet laser coupling structure: jet velocity: 50-200m / s (corresponding pressure 50-200MPa);

[0105] Jet diameter: 60μm (micromachining) to 300μm (roughmachining); laser power module (0-1000W continuously adjustable); nozzle with a sapphire sheet coated with a 5μm thick high-reflectivity film on the inner wall; quartz glass window; argon gas protective layer (flow rate 0.5L / min) is introduced around the nozzle to prevent water mist from scattering the laser. Open water cooling system: processing water undergoes three-stage filtration (5μm→1μm→0.1μm) before entering the laser cooling chamber. The heat exchanger reduces the water temperature from 60℃ to 25℃, with a heat recovery efficiency greater than 70%. Compared to traditional closed water cooling, this system dissipates heat directly through the jet medium, eliminating the need for an additional cooling tower.

[0106] 3. Parameter Matching Unit: This mainly includes a temperature sensor 410 (infrared thermometer, accuracy ±1℃); a water pressure sensor (piezoelectric ceramic type, range 0-300MPa); and a PID (proportional-integral-derivative) controller to adjust the laser power (response time less than 10ms). A proportional valve controls the water jet pressure (5-150MPa); when the temperature in the processing area is detected to be higher than the set threshold (e.g., 50℃), the system automatically increases the water jet velocity (+10%) and decreases the laser power (-5%).

[0107] This invention utilizes green heat dissipation: direct cooling of the laser by jet water; waste heat is used to preheat the inlet water (saving 15% energy); micro / nano structure fabrication; improved diffraction-limited resolution using short-wavelength blue light (theoretical limit λ / 2 = 225nm); water jet confinement of molten pool diffusion; and efficient absorption of blue light. Through the above technical solutions and system design, this invention achieves efficient synergy between blue laser and water jet, overcoming key technical bottlenecks such as high-reflectivity material processing, thermal damage control, and system heat dissipation.

[0108] The blue light-water jet coupling process of this invention:

[0109] 1. Laser incidence: After beam expansion and collimation, the blue laser is incident at an angle of 88° (close to the critical angle of total internal reflection) into the water jet inlet. By adjusting the Z-axis position of the focusing lens, the focal point of the beam is positioned within ±5μm of the central axis of the jet.

[0110] 2. Utilizing the low absorption characteristic of water for blue light (absorption coefficient a = 0.03 cm⁻¹) -1 The laser undergoes total internal reflection at the water-air interface (more than 50 reflections), forming a coaxial transmission of the "laser-water beam" with energy loss of less than 3%.

[0111] 3. High-pressure water jet (200μm diameter, 150m / s velocity) carries laser energy to impact the workpiece surface, with a water layer thickness of 50μm and a laser power density of 1×10⁻⁶. 7 W / cm 2 This enables the instantaneous vaporization of materials.

[0112] Furthermore, thermal damage control during processing: For magnesium alloy processing, the set temperature threshold is 40℃. When the infrared thermometer detects that the local temperature exceeds the limit, the PID controller 430 reduces the laser power from 500W to 475W within 10ms, while simultaneously increasing the water jet pressure from 80MPa to 88MPa, ensuring that the depth of the heat-affected zone (HAZ) is less than 5μm;

[0113] When the water jet impact pressure is greater than 100MPa, cavitation effect (cavitation collapse pressure is greater than 1GPa) can be generated, directly stripping away molten slag, and the surface roughness Ra of the processed surface is less than 0.8μm, without the need for secondary polishing;

[0114] In the fabrication of copper micro-hole arrays:

[0115] Workpiece: 0.2mm thick pure copper foil (reflectivity greater than 90%).

[0116] Parameters: Laser power 1000W, wavelength 455nm, water jet diameter 80μm, pressure 180MPa, scanning speed 1mm / s.

[0117] Results: Aperture consistency ±1.5μm, hole wall taper less than 2°, processing efficiency 3 times higher than green light system, and energy consumption reduced by 40%.

[0118] In the process of engraving magnesium alloy vascular stents:

[0119] Workpiece: Biodegradable magnesium alloy (AZ31B, 100μm thick).

[0120] Parameters: Laser power 350W, jet pressure 60MPa, argon flow rate 0.8L / min, scanning speed 4mm / s.

[0121] Results: Line width 15±0.5μm, HAZ depth 3.2μm, material degradation rate was not affected by processing.

[0122] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the paper parts and drawings of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A water jet assisted blue laser beam machining method, characterized by, The application relates to a device for water jet assisted blue laser beam processing, which comprises a blue laser beam generating module (100) for generating a laser beam with a wavelength of 450-470 nm; a water jet guiding module (200) comprising a high-pressure water pump (210) and a three-stage filtering device (220); a coaxial coupling processing head (300) integrating an aspheric lens focusing system (310) and a nozzle assembly (320); a dynamic control unit (400) comprising a temperature sensor (410) installed on the nozzle assembly (320) and a pressure sensor (420) at the outlet of the water pump; and an open heat management system (500) connected with a processing area and a laser cooler cavity through a pipeline. The nozzle assembly (320) comprises a fixed base (321) and a sapphire nozzle (322), and the inner wall of the nozzle is coated with a high reflection film layer. The water jet assisted blue laser beam processing method comprises the following steps: A laser beam is generated by the blue laser beam generating module (100) and is collimated and focused by an aspheric lens. The water jet guiding module (200) is driven to generate a high-pressure water jet, and the inner wall of the sapphire nozzle (322) is coated with a high reflection film layer. The laser beam is introduced into the water jet interface in the coaxial coupling processing head (300) to realize total reflection transmission. The dynamic control unit (400) is used for monitoring the processing temperature and adjusting parameters in linkage; the linkage adjustment comprises the following steps: when the temperature exceeds the standard, the water jet flow rate is increased and the laser power is reduced. The open heat management system (500) is used for recycling waste water to cool the laser.

2. The water jet assisted blue laser beam processing method according to claim 1, wherein when the laser is cooled, the water is preheated by a plate heat exchanger.

3. The water jet assisted blue laser beam processing method according to claim 1, wherein the position of the focusing lens is dynamically adjusted by an electric displacement table, so that the laser focal point is positioned on the central axis of the water jet.

4. The water jet assisted blue laser beam processing method according to claim 1, wherein the temperature sensor (410) is an infrared temperature measuring instrument, and the temperature sensor (410) is embedded in the fixed base (321).

5. The water jet assisted blue laser beam processing method according to claim 1, wherein the dynamic control unit (400) comprises a PID controller (430) configured to adjust the laser power and the water jet flow rate in linkage.

6. The water jet assisted blue laser beam processing method according to claim 1, wherein the open heat management system (500) comprises a spiral flow channel cooling cavity and a plate heat exchanger. ​ ​ ​ ​ ​

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