Water-jet guided laser cutting method suitable for large-size diamond

Abstract

The invention discloses a water-guided laser cutting method suitable for large-size diamonds, which comprises the following steps: dynamically dividing a center area, a transition area and an edge area along a kerf, and dividing a shallow layer boundary and a deep layer boundary according to depth; during processing, region and layer depth dual differentiation parameter regulation and control are adopted, exclusive energy, scanning rate and water beam pressure are configured for each region, and the corresponding region of each layer is adapted to different scanning intervals; cutting is carried out according to the sequence from the center to the edge, and smooth parameter connection is achieved through a transition area. According to the method, dynamic region division is combined with non-uniform layered design, energy and risks are balanced, the problems of non-uniform center penetration and poor edge penetration are solved, meanwhile, the penetration efficiency and the cutting quality are considered, and the method is suitable for the machining characteristics of large-size diamonds.

Description

Technical Field

[0001] This invention relates to the field of water-guided laser technology, and more specifically to a water-guided laser cutting method suitable for large-size diamonds. Background Technology

[0002] Traditional laser processing is a common technique for diamond cutting. However, direct laser irradiation will form a significant heat-affected zone on the surface and inside of the diamond, and the concentration of thermal stress will induce microcracks, which will seriously damage the material properties and processing accuracy. It cannot meet the stringent processing quality requirements of large-size diamonds (large-size ultra-thick diamonds with dimensions ≥20mm×20mm and thickness ≥5mm).

[0003] Water-guided laser (WJGL) technology, an advanced processing method combining water-guided light and cooling, achieves synchronous laser transmission and cooling of the processing area through a fine water jet. This effectively suppresses thermal stress, reduces crack formation, and significantly improves processing quality, making it a preferred solution for precision cutting of ultra-high hardness materials. However, in the through-cutting of large-size diamonds, existing water-guided laser processing solutions still face insurmountable technical bottlenecks, mainly including poor edge penetration and uneven center penetration.

[0004] To address the aforementioned issues, existing technologies often employ processing strategies based on uniform laser parameters, uniform layering, and single-path scanning. However, these strategies cannot accommodate the significant differences in energy loss, water jet stability, thermal diffusion efficiency, and stress distribution between the center and edges of large-sized diamonds, resulting in a mismatch between energy supply and regional processing requirements. Some improved solutions attempt to assist processing through multi-step, multi-stage cutting or pre-grooving, but these suffer from inherent drawbacks such as complex processes, low processing efficiency, and the potential for secondary thermal damage from multiple laser applications. Consequently, they cannot fundamentally solve the problems of poor edge penetration and uneven center penetration.

[0005] Therefore, developing a technical solution that can accurately adapt to the processing characteristics of large-size diamond regions, effectively balance energy compensation in the central region and risk control in the edge region, and achieve high-quality through-processing has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to address the problems of poor edge penetration and uneven center penetration in the cutting of large-size diamonds, and to provide a water-guided laser cutting method suitable for large-size diamonds. By dynamically dividing the region and combining it with a non-uniform layer design, the method balances energy and risk, solves the problems of uneven center penetration and poor edge penetration, and at the same time takes into account penetration efficiency and cutting quality, thus adapting to the processing characteristics of large-size diamonds.

[0007] To achieve the above object, the application adopts the following scheme: a water guide laser cutting method suitable for large-size diamond is proposed, which comprises the following steps:

[0008] The processing area is divided into sequentially connected first, second and third regions along the length direction of the preset cutting seam of the diamond to be processed; the first region is formed by extending the midpoint of the cutting seam to both sides by a first preset length, the second region is formed by extending both ends of the first region on the cutting seam to both sides by a second preset length, and the third region is formed by extending both ends of the second region on the cutting seam to both sides by a third preset length; the division boundaries of each region are dynamically determined based on the water beam propagation distance, heat diffusion path and stress concentration coefficient during diamond processing;

[0009] According to the thickness of the diamond to be processed, the processing depth is divided into sequentially connected first and second layers along the preset processing direction; the first layer is formed by extending the first surface of the diamond to be processed along the preset processing direction by a first preset depth, and the second layer is formed by extending the end surface away from the first surface of the first layer along the preset processing direction to the second surface opposite to the first surface of the diamond to be processed, and the depth of the first layer along the preset processing direction is less than the depth of the second layer;

[0010] Using the water guide laser process, the diamond to be processed is cut from the first layer to the second layer according to the preset program, until the through cutting of the diamond sheet is realized; during the cutting of each layer, the cutting is sequentially performed according to the order of the first, second and third regions, and the first, second and third regions are respectively cut using the preset processing energy, scanning speed and water beam pressure of the corresponding region; at the same time, during the layer-by-layer cutting from the first layer to the second layer, each region in each layer is cut using the preset scanning pitch of the corresponding region in the layer.

[0011] As an optional example, the first preset length L1 is 0

[0012] As an optional example, the second preset length L2 is L2=X-L1, 0.2L

[0013] As an optional example, the third preset length L3 is L3=0.5L-L1-L2.

[0014] As an optional example, the first preset depth T1 is 0.3T

[0015] As an optional example, the first layer is divided into a preset number of first sub-layers, and the second layer is divided into a preset number of second sub-layers; wherein the depth T1' of any first sub-layer along the processing direction is less than the depth T2' of any second sub-layer along the processing direction.

[0016] As an optional example, T2'= (2~2.5)T1'.

[0017] As an optional example, among the preset water guide laser processing parameters of the first region, the second region and the third region, the processing energy has a distribution trend of gradually decreasing, the scanning speed has a distribution trend of gradually increasing, and the water beam pressure has a distribution trend of gradually decreasing.

[0018] As an optional example, in the first layer and the second layer, the preset scanning pitch of the first region to the third region in each layer has a distribution trend of gradually increasing.

[0019] As an optional example, in the corresponding regions of the first layer and the second layer, the preset scanning pitch of the first region, the second region and the third region of the first layer is greater than the preset scanning pitch parameter of the corresponding region of the second layer.

[0020] As can be seen from the technical solutions of the present application above, the water guide laser cutting method suitable for large size diamond proposed by the present application dynamically divides the center, transition and edge three regions (first region, second region and third region) along the cutting seam, and the boundary is determined according to the characteristics of water beam propagation, heat diffusion and stress concentration, which can be adapted to the processing differences of different regions. At the same time, the shallow layer and the deep layer (the first layer and the second layer) are divided according to the depth, the shallow layer lays the processing foundation, and the deep layer matches the energy attenuation characteristics, and the layered cutting takes into account the penetration efficiency and quality.

[0021] In the processing, the region and layer depth dual difference parameters are used for control, the exclusive energy, scanning speed and water beam pressure are configured for each region, and different scanning pitches are adapted to the corresponding regions of each layer, so as to realize the balance of energy compensation in the center area and risk control in the edge area; the cutting is pushed forward in the order of center to edge, the parameter smooth connection is realized through the transition area, and the processing defects are avoided.

[0022] In this way, the processing demand of large size diamond is adapted, the cutting seam precision and penetration quality are ensured, and high efficiency is maintained at the same time, which has strong practicality and industrialization value. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 is the process flow chart of the water guide laser cutting method suitable for large size diamond of the present application.

[0024] Fig. 2 is the division schematic diagram of dynamic division region of the present application.

[0025] Fig. 3 is a structural schematic diagram of a non-uniform layered design of the present application. DETAILED DESCRIPTION

[0026] In order to better understand the technical content of the present application, specific embodiments are described below with reference to the accompanying drawings.

[0027] Aspects of the present application are described in the disclosure with reference to the accompanying drawings, which show many illustrative embodiments. The embodiments of the present disclosure are not necessarily intended to include all aspects of the present application. It should be understood that the various concepts and embodiments introduced above, as well as those described in more detail below, can be implemented in any of a number of ways.

[0028] When cutting large-size diamond with water-guided laser, on the one hand, the center area is faced with multiple energy and stability dilemmas. The center area is far away from the edge of the workpiece, and the vertical distance of the water beam needs to be propagated from the nozzle to the deep processing point is significantly increased (far beyond the stable length threshold of 4mm of pure water beam), and the laser energy is seriously lost in the water beam scattering, optical coupling deviation accumulation, resulting in that the effective energy of the deep layer is lower than the diamond ablation threshold; at the same time, the center area is completely surrounded by diamond material, and the dust and water vapor generated by processing cannot be quickly dispersed, forming local turbulent flow to destroy the stability of the water beam, and there is no effective heat dissipation channel to cause heat accumulation, further weakening the effective ablation energy, ultimately leading to incomplete center area penetration and uneven cut seam shape.

[0029] On the other hand, the edge area has a double contradiction of stress and energy. The edge area is affected by the superposition of fixture fixing force and cutting thermal stress, and the stress concentration coefficient is higher than that of the center area, which is easy to induce cracks due to improper energy input; at the same time, the laser needs to go through multiple interface reflection of water beam-air-diamond, which causes additional energy loss, and the path of the water beam exposed to the air is longer, which is easy to cause light guiding deviation under the interference of external airflow, leading to insufficient energy supply and processing precision deviation in the edge area, and finally forming defects such as poor penetration effect and cut seam edge collapse.

[0030] Therefore, problems of uneven center penetration and poor edge penetration are prone to occur during processing.

[0031] Therefore, the present application constructs a water-guided laser cutting method suitable for large-size diamond, dynamically divides the area to adapt to the processing characteristics, solves the problems of uneven center penetration and poor edge penetration; the non-uniform layered design takes into account the penetration efficiency and quality; the differentiated parameters realize accurate regulation and control, balance energy and risk; orderly processing ensures stability and improves cut seam precision; adapts to the demand of large-size diamond, and is practical and efficient.

[0032] In combination with Figs. 1-3 As shown in FIG. 1, in one embodiment, a water-guided laser cutting method suitable for large-size diamond is provided, which comprises the following steps:

[0033] [Dynamic division of regions]

[0034] As shown in Fig. 2 , the processing region is divided into sequentially connected first region 1, second region 2 and third region 3 along the length L direction of the preset kerf of the diamond to be processed; wherein the first region is formed by extending the first preset length L1 from the midpoint O of the kerf to both sides, the second region is formed by extending the second preset length L2 from both ends (A1, A2) of the first region on the kerf to both sides respectively, and the third region is formed by extending the third preset length L3 from both ends (B1, B2) of the second region on the kerf to both sides respectively; the division boundaries of each region are dynamically determined based on the water beam propagation distance, heat diffusion path and stress concentration coefficient during diamond processing.

[0035] In some embodiments, the first preset length L1 is 0 < L1 ≤ 0.2L, and L is the length of the kerf.

[0036] In some embodiments, the second preset length L2 is L2 = X - L1, 0.2L < X ≤ 0.45L.

[0037] In some embodiments, the third preset length L3 is L3 = 0.5L - L1 - L2.

[0038] [Non-uniform layered design]

[0039] As shown in Fig. 3 , according to the preset thickness T of the diamond to be processed, the processing depth is divided into sequentially connected first layer 4 and second layer 5 along the preset processing direction; wherein the first layer is formed by extending the first preset depth T1 from the first surface of the diamond to be processed along the preset processing direction, the second layer is formed by extending the end surface away from the first surface of the first layer to the second surface opposite to the first surface of the diamond to be processed along the preset processing direction, and the depth (T1) of the first layer along the preset processing direction is less than the depth (T2) of the second layer.

[0040] In some embodiments, the first preset depth T1 is 0.3T ≤ T1 < 0.5T, and T is the thickness of the diamond sheet.

[0041] In some embodiments, the first layer is divided into a preset number of first sub-layers 41, and the second layer is divided into a preset number of second sub-layers 51; wherein the depth T1' of any first sub-layer along the processing direction is less than the depth T2' of any second sub-layer along the processing direction.

[0042] In some embodiments, T2' = (2~2.5)T1'.

[0043] [Design of processing parameters for different regions and different layers]

[0044] In some embodiments, among the preset water guide laser processing parameters of the first region, the second region and the third region, the processing energy presents a distribution trend of gradually decreasing, the scanning speed presents a distribution trend of gradually increasing, and the water beam pressure presents a distribution trend of gradually decreasing; the energy density of the first region to the third region is set to present a decreasing trend.

[0045] In some specific examples, the water guide laser processing parameters of the first region include: laser single pulse energy of 0.60 mJ-0.65 mJ, laser repetition frequency of 10 KHz-12 KHz, scanning speed of 0.8 mm / s-0.9 mm / s, water beam pressure of 280 bar-300 bar, and laser average power≥7.2 W to compensate for the energy attenuation caused by the too long water beam propagation distance in the central region.

[0046] The water guide laser processing parameters of the second region include: laser single pulse energy of 0.50 mJ-0.55 mJ, laser repetition frequency of 9 KHz-10 KHz, scanning speed of 1.0 mm / s-1.1 mm / s, water beam pressure of 250 bar-280 bar, and average power of 5.0 W-5.5 W to achieve smooth transition of energy in the central region and the edge region.

[0047] The water guide laser processing parameters of the third region include: laser single pulse energy of 0.45 mJ-0.50 mJ, laser repetition frequency of 7 KHz-8 KHz, scanning speed of 1.1 mm / s-1.2 mm / s, water beam pressure of 250 bar-260 bar, and average power≤4.0 W, and the ratio of scanning speed to laser repetition frequency≥137.5 mm -1 ・s・KHz to avoid cracks induced by stress concentration in the edge region.

[0048] In some other examples, the laser single pulse energy of the second region is relatively higher when close to the first region and relatively lower when close to the third region, so as to achieve a smooth transition, and the change point can be the midpoint of the distance of the region as the demarcation point.

[0049] In some embodiments, in the first layer and the second layer, the preset scanning intervals of the first region to the third region in each layer present a distribution trend of gradually increasing.

[0050] In some embodiments, in the corresponding regions of the first layer and the second layer, the preset scanning intervals of the first region, the second region and the third region of the first layer are greater than the preset scanning interval parameters of the corresponding regions of the second layer, respectively.

[0051] In some specific examples, the scanning spacing of the first layer includes: 0.2 μm for the first region, 0.35 μm for the second region, and 0.45 μm for the third region. The upper layer has sufficient energy, and the edge path is thinned to prevent thermal damage.

[0052] The scanning spacing of the second layer includes: 0.15 μm for the first region, 0.3 μm for the second region, and 0.4 μm for the third region. The lower layer has more energy attenuation and a denser central region path.

[0053] [Water-guided laser cutting of large-size diamonds]

[0054] Using water-guided laser technology, the diamond to be processed is cut layer by layer from the first layer to the second layer according to a preset program until a through-cut is achieved. During the cutting process of each layer, the first, second and third regions are cut in sequence, and the first to third regions are cut using preset processing energy, scanning rate and water jet pressure respectively. At the same time, during the layer-by-layer cutting process from the first layer to the second layer, the preset scanning interval for each region in each layer is used to complete the cutting processing of each region in the corresponding layer.

[0055] Below, in conjunction with Figs. 1-3 As shown, we use a water-guided laser to cut a large-size CVD diamond heat sink (length × width × height = 20mm × 20mm × 6mm; cut requirements: top opening ≤ 75 μm, bottom opening ≥ 50 μm) to illustrate the implementation of the process of the present invention in more detail.

[0056] (1) Sample pretreatment: The diamond slices were ultrasonically cleaned with anhydrous ethanol, rinsed with distilled water and dried to ensure surface cleanliness and stabilize optical-water coupling.

[0057] (2) Sample fixation: Stress-concentrated, in-plane limiting fixtures are used for fixation to ensure positioning accuracy and perpendicularity.

[0058] (3) Dynamic division of regions: First region: 4 mm from the center point of the cut to both sides; Second region: 5 mm from the two endpoints of the first region on the cut to both sides; Third region: 1 mm from the two endpoints of the second region on the cut to both sides.

[0059] Layered planning: First layer: The first surface of the diamond to be processed extends 2.4 mm (0~2.4 mm) along the preset processing direction and is divided into 3 sub-layers, each with a thickness of 0.8 mm; Second layer: The remaining 2.4~6 mm is divided into 2 sub-layers, each with a thickness of 1.8 mm.

[0060] (4) Design of water-guided laser processing parameters

[0061] The water-guided laser processing parameters of the first region are as follows: laser single pulse energy is 0.65 mJ, laser repetition frequency is 12 KHz, scanning speed is 0.8 mm / s, and water beam pressure is 300 bar;

[0062] The water-guided laser processing parameters of the second region are as follows: laser single pulse energy is 0.55 mJ close to the first region and 0.50 mJ close to the third region (taking the midpoint of the distance as the demarcation point), laser repetition frequency is 10 KHz, scanning speed is 1.0 mm / s, and water beam pressure is 280 bar;

[0063] The water-guided laser processing parameters of the third region are as follows: laser single pulse energy is 0.45 mJ, laser repetition frequency is 8 KHz, scanning speed is 1.2 mm / s, and water beam pressure is 250 bar.

[0064] The scanning pitch of the first layer includes: the first region is 0.2 μm, the second region is 0.35 μm, and the third region is 0.45 μm.

[0065] The scanning pitch of the second layer includes: the first region is 0.15 μm, the second region is 0.3 μm, and the third region is 0.4 μm.

[0066] (5) Water-guided laser cutting: cutting from the first layer to the second layer in the region to be processed, and in the cutting process of each layer, the parameters of step (4) are used to cut in the order of the first region, the second region and the third region, and direct cutting is completed.

[0067] (6) After cutting, the sample is cleaned by ultrasonic cleaning with anhydrous ethanol, and quality inspection is performed.

[0068] The ultrasonic flaw detector shows that there is no non-penetrating region; the laser profiler shows that the upper opening is 72 μm, the lower opening is 50 μm, and the cutting seam taper is 1.85°; the metallography shows that there is no crack of ≥5 μm, and the spectrum shows that the sample is 1580 cm -1 There is no graphite characteristic peak and no graphitization signal; the stress test center is 45 MPa, and the edge is 62 MPa; the results are within the qualified standard.

[0069] From the above, the advantages of the method of the application are as follows:

[0070] (1) Through the regional dynamic division of processing characteristics, the regional difference problem is accurately solved; the processing region is dynamically divided according to the first region (center), the second region (transition) and the third region (edge) along the length direction of the cutting seam, and the boundary is determined according to the water beam propagation distance, heat diffusion path and stress concentration coefficient, which can match the energy attenuation and stress distribution difference of different regions, avoid the center energy shortage and edge stress concentration problem caused by traditional uniform processing from the spatial dimension, and effectively improve the defects of uneven center penetration and poor edge penetration.

[0071] (2) Through hierarchical design optimization of deep processing, the penetration efficiency and quality are considered; the first layer (shallow layer) and the second layer (deep layer) are divided according to the processing depth, and the depth of the first layer is less than that of the second layer, combined with the cutting sequence from the first layer to the second layer, which lays a foundation through shallow fine processing, and adapts the processing strategy to the characteristics of more significant energy attenuation in deep layer, avoids the deep energy shortage or shallow heat damage caused by single hierarchical, and improves the consistency of penetration processing.

[0072] (3) Precise regulation is realized through differentiated parameter adaptation, balancing energy and risk; the processing energy, scanning rate and water beam pressure are configured for different regions (first to third regions), and different scanning spacings are adapted for the same region in different layers, realizing the double parameter precise regulation of region and layer depth; the first region (center) can compensate for energy attenuation through high energy and dense spacing, and the third region (edge) can control stress and heat damage through low energy and sparse spacing, considering the center penetration and edge processing quality.

[0073] (4) The ordered processing sequence ensures the stability of the process and improves the overall processing precision; each layer is cut in the order of the first region to the third region, and the transition region is used to realize the smooth connection of energy and parameters, avoiding the processing defects caused by parameter mutation between regions, ensuring the stability and continuity of the cutting process, and finally improving the overall precision and consistency of large-size diamond cutting seam.

[0074] In this way, the method of the present application not only solves the problem of the traditional method that cannot adapt to the regional and layer depth difference, but also maintains the processing efficiency under the premise of ensuring the penetration quality through the modular processing logic of layer by layer and partition, avoids multiple rework or complex auxiliary process, and has strong industrial application value.

[0075] Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Those skilled in the art without departing from the spirit and scope of the present application can make various modifications and improvements. Therefore, the protection scope of the present application shall be subject to the definition of the claims.

Claims

1. A water guided laser cutting method suitable for large size diamonds, characterized in that, Includes the following steps: Based on the pre-set kerf of the diamond to be processed, the processing area is divided into a first region, a second region, and a third region along the length of the kerf. The first region is formed by extending a first pre-set length from the midpoint of the kerf to both sides. The second region is formed by extending a second pre-set length from the two endpoints of the first region on the kerf to both sides. The third region is formed by extending a third pre-set length from the two endpoints of the second region on the kerf to both sides. The boundaries of each region are dynamically determined based on the water jet propagation distance, heat diffusion path, and stress concentration factor during diamond processing. Based on the preset thickness of the diamond to be processed, the processing depth is divided into a first layer and a second layer connected sequentially along the preset processing direction; wherein, the first layer is formed by the first surface of the diamond to be processed extending a first preset depth along the preset processing direction, and the second layer is formed by the end face of the first layer away from the first surface extending along the preset processing direction to a second surface opposite to the first surface of the diamond to be processed, and the depth of the first layer along the preset processing direction is less than the depth of the second layer. Using water-guided laser technology, the diamond to be processed is cut layer by layer from the first layer to the second layer according to a preset program until a through-cut is achieved. During the cutting process of each layer, the first, second and third regions are cut in sequence, and the first to third regions are cut using preset processing energy, scanning rate and water jet pressure respectively. At the same time, during the layer-by-layer cutting process from the first layer to the second layer, the preset scanning interval for each region in each layer is used to complete the cutting processing of each region in the corresponding layer.

2. The water guided laser cutting method suitable for large size diamond as claimed in claim 1 wherein, The first preset length L1 is 0 < L1 ≤ 0.2L, where L is the kerf length.

3. The water guided laser cutting method suitable for large size diamonds according to claim 2, characterized in that, The second preset length L2 is L2=X-L1, 0.2L<X≤0.45L.

4. The water guided laser cutting method suitable for large size diamonds according to claim 3, characterized in that, The value of the third preset length L3 is L3 = 0.5L - L1 - L2.

5. The water guided laser cutting method suitable for large size diamonds according to claim 1, characterized in that, The first preset depth T1 is 0.3T≤T1<0.5T, where T is the thickness of the diamond sheet.

6. The water guided laser cutting method suitable for large size diamonds according to claim 1, characterized in that, The first layer is divided into a predetermined number of first sub-layers, and the second layer is divided into a predetermined number of second sub-layers; wherein the depth T1' of any first sub-layer along the processing direction is less than the depth T2' of any second sub-layer along the processing direction.

7. The water-conducting laser cutting method for large-size diamonds according to claim 1, characterized in that, T2' = (2~2.5)T1'.

8. The water-conducting laser cutting method for large-size diamonds according to claim 1, characterized in that, In the preset water-guided laser processing parameters of the first, second, and third regions, the processing energy shows a decreasing trend, the scanning rate shows an increasing trend, and the water beam pressure shows a decreasing trend.

9. The water-conducting laser cutting method for large-size diamonds according to claim 1, characterized in that, In the first and second layers, the preset scanning spacing between the first and third regions in each layer shows a sequentially increasing distribution trend.

10. The water-conducting laser cutting method for large-size diamonds according to claim 1, characterized in that, In the corresponding regions of the first and second layers, the preset scanning spacing of the first, second, and third regions of the first layer is greater than the preset scanning spacing parameter of the corresponding region of the second layer.

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