Water guide laser intermittent machining method for three-dimensional complex structure

Abstract

The present application belongs to the field of laser intermittent machining method, and particularly relates to a water guide laser intermittent machining method for three-dimensional complex structure, comprising the following steps: S1, rotating the super-hydrophobic baffle to periodically deflect at a rotation speed of 10-200 rpm, and switching the water flow on and off through an angle change of 0-15 degrees; S2, collecting water flow impact pressure data in real time by a pressure sensor to generate a dynamic electrical signal; S3, sending a pulse on-off instruction to a laser modulation module based on the amplitude mutation characteristics of the electrical signal; S4, adjusting the feeding speed and laser emission frequency according to the curvature radius value of the machining path by a multi-axis linkage mechanism. Through the dynamic water guide of the rotating baffle and the laser-motion collaborative control, the water flow on and off does not need to restart the high-pressure system, and the machining efficiency is doubled; the pressure sensor triggers the laser pulse in real time, and eliminates the invalid energy dissipation; the multi-axis linkage adapts to the curvature change, and the machining precision of the complex structure reaches the micron level.

Description

Technical Field

[0001] This invention belongs to the field of laser discontinuous processing methods, specifically relating to a water-guided laser discontinuous processing method for three-dimensional complex structures. Background Technology

[0002] While water-guided laser processing technology combines the advantages of high laser energy density and water cooling, it faces the following challenges in processing complex three-dimensional structures:

[0003] 1. The contradiction between processing efficiency and structural complexity: continuous water flow is difficult to adapt to the three-dimensional path processing of thin-walled / brittle materials, which can easily lead to structural deformation;

[0004] 2. Conflict between system stability and machining accuracy: Traditional intermittent machining requires repeated starting and stopping of the high-pressure pump, resulting in more than 30% of the time being wasted on constraint layer reconstruction, with each interruption requiring 3-5ms of stabilization time. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention provides a water-guided laser intermittent machining method for three-dimensional complex structures, which effectively solves the contradiction between machining efficiency and structural complexity: continuous water flow is difficult to adapt to three-dimensional path machining of thin-walled / brittle materials, which can easily cause structural deformation; there is a contradiction between system stability and machining accuracy: traditional intermittent machining requires repeated starting and stopping of high-pressure pumps, resulting in more than 30% of the time being wasted on constraint layer reconstruction, and each interruption requires 3-5ms of stabilization time.

[0006] One embodiment of the present invention provides a method for intermittent laser processing of water-guided structures for complex three-dimensional structures, comprising the following steps:

[0007] S1. The rotating superhydrophobic baffle deflects periodically at a speed of 10-200 rpm, switching the water flow interruption by changing the angle from 0 degrees to 15 degrees.

[0008] S2. The pressure sensor collects water flow impact pressure data in real time and generates dynamic electrical signals.

[0009] S3. Based on the characteristics of abrupt changes in the amplitude of the electrical signal, a pulse start-up / shutdown command is sent to the laser modulation module;

[0010] S4. The multi-axis linkage mechanism adjusts the feed speed and laser emission frequency in conjunction with the radius of curvature of the machining path.

[0011] In one embodiment, step S1 further includes:

[0012] The baffle surface is laser-processed with a microgroove array, with a groove width of 20μm, a spacing of 50μm, and a depth of 15μm. After being impregnated with a fluorosilane solution, a superhydrophobic interface with a contact angle greater than 160 degrees is formed.

[0013] In one embodiment, step S1 further includes:

[0014] When the baffle is deflected to 15 degrees, the water flow is completely refracted into the recycling channel by the guide surface;

[0015] When the baffle returns to 0 degrees, the high-pressure water flow reconstructs the direct jet within 20ms.

[0016] In one embodiment, step S2 further includes:

[0017] The pressure sensor monitors water flow pressure at a sampling rate of 10kHz and outputs a high-level signal when the pressure value jumps from 0MPa to above 6MPa.

[0018] In one embodiment, step S3 further includes:

[0019] After receiving a high-level signal, the laser modulation module starts a 532nm wavelength laser pulse sequence within 0.5ms, with the pulse width adjusted to 10-100ns.

[0020] In one embodiment, step S4 further includes:

[0021] When the path curvature radius drops to a critical value of less than 0.5mm, the following cooperative operation is automatically performed:

[0022] Reduce the feed rate to below 30% of the baseline value;

[0023] Increase the laser pulse frequency to above 80kHz;

[0024] Increase the single-pulse energy density to the level of 15 J / cm².

[0025] In one embodiment, during the interruption of water flow by baffle deflection, the multi-axis mechanism moves to the next processing coordinate point, and the displacement distance is dynamically calculated by the derivative of path curvature.

[0026] In one embodiment, step S3 further includes:

[0027] When processing brittle materials, the laser modulation module is configured with a pulse combination with a repetition frequency greater than 50 kHz and a pulse width less than 50 ns.

[0028] One embodiment of the present invention provides a method for processing a biodegradable magnesium alloy scaffold. Based on the water-guided laser intermittent processing method for three-dimensional complex structures described in any of the above embodiments, during the scaffold node processing stage, the baffle is deflected at a rotation speed of 120 rpm, the water flow interruption time ratio is set to 3:7, and the synchronous laser power is set to 80W.

[0029] One embodiment of the present invention provides a method for processing curved microlens arrays. Based on the water-guided laser intermittent processing method for three-dimensional complex structures described in any of the above embodiments, for the region with a curvature radius of 1-5mm, the baffle deflection angle is adjusted in a gradient of 5 degrees to 12 degrees, and the synchronous laser energy density distribution is matched with the curved surface normal vector.

[0030] The above technical solution provides a water-guided laser intermittent processing method for three-dimensional complex structures, which has the following beneficial effects:

[0031] 1. Intermittent water flow impact combined with displacement compensation reduces the fracture rate of brittle materials to a negligible level, especially for thin-walled structures such as 100μm-level magnesium alloy supports, eliminating the risk of node fracture caused by stress concentration; precise matching of water flow cooling and pulse energy enables the surface roughness of optical components such as microlens arrays to enter the submicron level, the width of the heat-affected zone to be narrowed to one-tenth of that of traditional processes, the contour accuracy of complex three-dimensional structures to the wavelength level, and the taper of the hole wall to approach the theoretical limit value.

[0032] 2. Dynamic deflection of the baffle maintains laminar flow, avoiding repeated reconstruction of water flow and significantly shortening the processing cycle of complex parts. The superhydrophobic micro-nano structure design improves the high pressure impact resistance of key components, and the wear is reduced by two orders of magnitude compared with traditional mechanical valves. The precise synchronization of the laser emission window with the water flow phase eliminates ineffective energy dissipation and ensures the consistency of the entire process.

[0033] 3. Supports stable processing of ultra-thin and brittle materials (monocrystalline silicon, special glass) at the 20μm level, with controllable breakage risk, enabling full-path forming of complex biological scaffolds with curvature radii of less than 0.3mm, and bringing the array structure consistency error into the micron range. Attached Figure Description

[0034] 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.

[0035] Figure 1 This is a diagram of the superhydrophobic surface microstructure of the present invention;

[0036] Figure 2 This is a timing diagram for the water flow control of the present invention;

[0037] Figure 3 This is a cross-section showing the working principle of the baffle of the present invention. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0039] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0040] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0041] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0042] Combination Figures 1 to 3 As shown, one embodiment of the present invention provides a method for intermittent laser processing of water-guided structures for complex three-dimensional structures, including the following steps:

[0043] S1. The rotating superhydrophobic baffle deflects periodically at a speed of 10-200 rpm, switching the water flow interruption by changing the angle from 0 degrees to 15 degrees.

[0044] S2. The pressure sensor collects water flow impact pressure data in real time and generates dynamic electrical signals.

[0045] S3. Based on the characteristics of abrupt changes in the amplitude of the electrical signal, a pulse start-up / shutdown command is sent to the laser modulation module;

[0046] S4. The multi-axis linkage mechanism adjusts the feed speed and laser emission frequency in conjunction with the radius of curvature of the machining path.

[0047] In this embodiment of the invention, traditional water-guided laser processing suffers from thin-walled structure deformation due to water flow impact during three-dimensional path processing, and the time consumed by repeated water flow reconstruction accounts for more than 30%. This invention achieves the following through dynamic flow guidance by rotating baffle and laser-motion coordinated control: water flow interruption does not require restarting the high-pressure system, thus doubling processing efficiency; pressure sensing triggers laser pulses in real time, eliminating ineffective energy dissipation; multi-axis linkage adaptive curvature change enables the processing accuracy of complex structures to reach the micron level.

[0048] In one embodiment, step S1 further includes:

[0049] The baffle surface is laser-processed with a microgroove array, with a groove width of 20μm, a spacing of 50μm, and a depth of 15μm. After being impregnated with a fluorosilane solution, a superhydrophobic interface with a contact angle greater than 160 degrees is formed.

[0050] In this embodiment of the invention, traditional baffles are prone to turbulence under 20MPa high pressure, leading to loss of control over processing accuracy. This invention, however, features a microgroove array (groove width 20μm / spacing 50μm) combined with fluorosilane modification, resulting in a contact angle greater than 160 degrees; a super-lubricating interface reduces water flow shear resistance by 70%, maintaining laminar flow with a Re value less than 2300; and high-pressure wear is only 0.5μm / 200 hours, extending the lifespan.

[0051] In one embodiment, step S1 further includes:

[0052] When the baffle is deflected to 15 degrees, the water flow is completely refracted into the recycling channel by the guide surface;

[0053] When the baffle returns to 0 degrees, the high-pressure water flow reconstructs the direct jet within 20ms.

[0054] In this embodiment of the invention, to address the problem of water flow impact damage to brittle materials, the baffle is deflected at 15 degrees to refract the water flow to the recovery channel, completely isolating the processing area. When the baffle is reset at 0 degrees, the direct flow stream is reconstructed within 20ms, improving laminar flow stability. Displacement compensation during the interruption period eliminates the risk of microcrack propagation.

[0055] In one embodiment, step S2 further includes:

[0056] The pressure sensor monitors water flow pressure at a sampling rate of 10kHz and outputs a high-level signal when the pressure value jumps from 0MPa to above 6MPa.

[0057] In this embodiment of the invention, millisecond-level response ensures precise synchronization between laser and water flow, solving the problem of laser energy waste caused by traditional sensing delay. 10kHz pressure sampling captures the characteristics of sudden changes in water flow, and electrical signals trigger the laser pulse sequence with a response delay of less than 0.5ms. Dynamic matching of processing phase improves energy utilization.

[0058] In one embodiment, step S3 further includes:

[0059] After receiving a high-level signal, the laser modulation module starts a 532nm wavelength laser pulse sequence within 0.5ms, with the pulse width adjusted to 10-100ns.

[0060] In this embodiment of the invention, in response to the thermal damage problem of heat-sensitive materials, the 532nm wavelength laser has both high absorption rate and low thermal diffusion characteristics, and the pulse width is adjustable from 10 to 100ns. The heat-affected zone is narrowed to less than 2μm. The short pulse width strategy reduces the heat input of silicon materials.

[0061] In one embodiment, step S4 further includes:

[0062] When the path curvature radius drops to a critical value of less than 0.5mm, the following cooperative operation is automatically performed:

[0063] Reduce the feed rate to below 30% of the baseline value;

[0064] Increase the laser pulse frequency to above 80kHz;

[0065] Increase the single-pulse energy density to the level of 15 J / cm².

[0066] In this embodiment of the invention, the traditional method requires the speed to be reduced to 20 mm / s on sharp curves, resulting in decreased efficiency. However, the present invention automatically reduces the speed to below 50 mm / s when the radius of curvature is less than 0.5 mm, and simultaneously increases the laser frequency to 80 kHz, achieving an energy density of 15 J / cm² per unit area, suppressing the heat accumulation effect, and improving the path following accuracy.

[0067] In one embodiment, during the interruption of water flow by baffle deflection, the multi-axis mechanism moves to the next processing coordinate point, and the displacement distance is dynamically calculated by the derivative of path curvature.

[0068] In this embodiment of the invention, to address the issue of time consumption during path transition idle travel, the multi-axis mechanism moves to the next coordinate point during the water flow interruption period. The displacement distance is dynamically calculated based on the curvature derivative, and the positioning error is less than 1μm. In conjunction with the laser standby mode, the proportion of invalid time consumption is reduced.

[0069] In one embodiment, step S3 further includes:

[0070] When processing brittle materials, the laser modulation module is configured with a pulse combination with a repetition frequency greater than 50 kHz and a pulse width less than 50 ns.

[0071] In this embodiment of the invention, a high-frequency pulse greater than 50kHz disperses the heat input, and a short pulse width of less than 50ns limits the heat diffusion depth, reducing the stress peak to below 60% of the material's yield strength, thereby solving the problem of microcrack propagation in brittle materials.

[0072] It should be noted that the intermittent water flow impact combined with displacement compensation reduces the fracture rate of brittle materials to a negligible level, especially for thin-walled structures such as 100μm-level magnesium alloy scaffolds, eliminating the risk of node fracture caused by stress concentration; the precise matching of water flow cooling and pulse energy enables the surface roughness of optical components such as microlens arrays to enter the submicron level, the width of the heat-affected zone to be narrowed to one-tenth of that of traditional processes, the contour accuracy of complex three-dimensional structures to the wavelength level, and the taper of the hole wall to approach the theoretical limit value; the dynamic deflection of the baffle maintains the laminar flow state, avoids the time-consuming repeated reconstruction of water flow, and significantly shortens the processing cycle of complex parts; the superhydrophobic micro-nano structure design improves the high-pressure impact resistance of key components, and the wear is reduced by two orders of magnitude compared with traditional mechanical valves; the precise synchronization of the laser emission window period with the water flow phase eliminates ineffective energy dissipation and ensures the consistency of the entire process; this invention supports the stable processing of 20μm-level ultrathin brittle materials (single crystal silicon, special glass), with controllable breakage risk, and realizes the full-path forming of complex biological scaffolds with a curvature radius of less than 0.3mm, with the array structure consistency error entering the micron range.

[0073] One embodiment of the present invention provides a method for processing a biodegradable magnesium alloy scaffold. Based on the water-guided laser intermittent processing method for three-dimensional complex structures described in any of the above embodiments, during the scaffold node processing stage, the baffle is deflected at a rotation speed of 120 rpm, the water flow interruption time ratio is set to 3:7, and the synchronous laser power is set to 80W.

[0074] In this embodiment of the invention, the baffle rotates at 120 rpm to optimize stress distribution, the water flow interruption ratio is 3:7 to control the impact energy at the nodes, and the 80W laser power ensures that the width fluctuation is ≤±3μm.

[0075] One embodiment of the present invention provides a method for processing curved microlens arrays. Based on the water-guided laser intermittent processing method for three-dimensional complex structures described in any of the above embodiments, for the region with a curvature radius of 1-5mm, the baffle deflection angle is adjusted in a gradient of 5 degrees to 12 degrees, and the synchronous laser energy density distribution is matched with the curved surface normal vector.

[0076] In this embodiment of the invention, the baffle deflection angle is matched with the curvature in a gradient of 5 degrees to 12 degrees, the laser energy density is distributed along the normal vector of the curved surface, and the contour accuracy error is less than 0.5 μm, thereby solving the problem of transmittance fluctuation caused by uneven energy distribution on the curved surface.

[0077] 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 method for intermittent laser processing of water-guided structures for complex three-dimensional structures, characterized in that, Includes the following steps: S1. A rotating superhydrophobic baffle deflects periodically at a speed of 10-200 rpm, switching the water flow between 0 and 15 degrees. The surface of the baffle is laser-processed with a micro-groove array, with a groove width of 20 μm, a spacing of 50 μm, and a depth of 15 μm. The micro-groove array is impregnated with a fluorosilane solution to form a superhydrophobic interface with a contact angle >160 degrees. When the baffle deflects to 15 degrees, the water flow is completely refracted into the recovery channel by the guide surface. When the baffle returns to 0 degrees, the high-pressure water flow reconstructs the direct jet within 20 ms. S2. The pressure sensor collects water flow impact pressure data in real time and generates dynamic electrical signals. The pressure sensor monitors water flow pressure at a sampling rate of 10kHz. When the pressure value jumps from 0MPa to above 6MPa, it outputs a high-level signal. S3. Based on the abrupt change characteristics of the electrical signal amplitude, a pulse start / stop command is sent to the laser modulation module; after receiving the high-level signal, the laser modulation module starts a 532nm wavelength laser pulse sequence within 0.5ms, and the pulse width is adjusted to 10-100ns. S4. The multi-axis linkage mechanism adjusts the feed speed and laser emission frequency in conjunction with the radius of curvature of the machining path.

2. The method for intermittent laser processing of water-guided structures as described in claim 1, characterized in that, Step S4 further includes: When the path curvature radius drops to a critical value of less than 0.5mm, the following cooperative operation is automatically performed: Reduce the feed rate to below 30% of the baseline value; Increase the laser pulse frequency to above 80kHz; Increase the single-pulse energy density to the level of 15 J / cm².

3. The method for intermittent laser processing of water-guided structures as described in claim 2, characterized in that, During the interruption of water flow by the baffle deflection, the multi-axis mechanism moves to the next processing coordinate point, and the displacement distance is dynamically calculated by the derivative of the path curvature.

4. The method for intermittent laser processing of water-guided structures as described in claim 3, characterized in that, Step S3 further includes: When processing brittle materials, the laser modulation module is configured with a pulse combination with a repetition frequency > 50 kHz and a pulse width < 50 ns.

5. A method for fabricating a biodegradable magnesium alloy scaffold, based on the water-guided laser discontinuous fabrication method for three-dimensional complex structures as described in any one of claims 1-4, characterized in that, During the support node processing stage, the baffle deflects at a speed of 120 rpm, the water flow interruption time ratio is set to 3:7, and the synchronous laser power is set to 80W.

6. A method for fabricating a curved microlens array, based on the water-guided laser discontinuous fabrication method for three-dimensional complex structures as described in any one of claims 1-4, characterized in that, For the curvature radius of 1-5mm, the baffle deflection angle is adjusted in a gradient of 5 degrees to 12 degrees, and the synchronous laser energy density distribution is matched with the surface normal vector.

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