Edge breakage prevention method for multi-line cutting of crystal material

Abstract

The invention belongs to the technical field of crystal material precision machining, and particularly relates to an edge breakage prevention method for a multi-wire cutting crystal material, which comprises the steps of preparing a crystal to be cut, selecting a protective material, fixing the protective material, carrying out multi-wire cutting operation and carrying out subsequent treatment. The protective material is tightly attached to the to-be-cut surface of the crystal in a vacuum or electrostatic adsorption mode and is matched with mainstream multi-wire cutting equipment, cutting parameters are accurately controlled, and the protective material is cleaned and reused after cutting. Stress buffering is achieved through the moderate elasticity of the acrylic glass, visualization of the cutting process is guaranteed through high light transmittance, the material cost is low, repeated use is achieved, and equipment does not need to be transformed. By applying the method, the edge breakage rate of brittle crystals such as yttrium vanadate can be reduced to 1% or below, the yield is increased to 99% or above, the comprehensive processing cost is reduced by 60% or above, and the method is suitable for high-end processing scenes such as laser crystals and semiconductor substrates and has wide popularization value.

Description

Technical Field

[0001] This invention belongs to the field of precision machining technology for crystal materials, and specifically relates to a method for preventing edge chipping in multi-wire cutting of crystal materials. Background Technology

[0002] Multi-wire cutting technology, with its advantages of high cutting efficiency (cutting a single 100mm×100mm crystal takes more than 60% less time than traditional inner circle cutting), good processing accuracy (the flatness of the cut surface can reach 0.005mm / 100mm), and the ability to achieve batch processing, has become the mainstream processing method for brittle crystalline materials such as yttrium vanadate, sapphire, and silicon carbide. However, due to their inherent crystal structure characteristics, brittle crystals generally have a hardness higher than 600HV and a toughness lower than 2 MPa·m¹. / ². During the cutting process, the mechanical impact (impact load can reach 50-80N) and local stress concentration (stress peak can reach 200-300MPa) generated by the high-speed operation of the cutting wire (commonly diamond wire with a diameter of 0.12-0.18mm) can easily lead to chipping at the crystal edge (i.e., "edge chipping"). Yttrium vanadate crystal, as a commonly used laser gain medium, is widely used in solid-state lasers, optical communication devices, and other fields. Its Mohs hardness reaches 5.5-6.0, but its fracture toughness is only 1.2-1.5 MPa·m¹ / ², edge chipping is a particularly prominent issue in traditional multi-wire cutting processes, severely hindering the mass production efficiency of high-end laser devices. According to industry testing standards, crystals are considered defective when the chipping size exceeds 20μm. This type of chipping can increase the dimensional accuracy deviation of products to over ±0.03mm and the surface roughness Ra to over 1.2μm, directly leading to a decrease in yield. Statistics show that edge chipping-related scrap rates account for over 75% of the total scrap rate for yttrium vanadate crystals in traditional multi-wire cutting processes.

[0003] Existing technologies for solving crystal cutting edge chipping mainly have the following drawbacks:

[0004] 1. Mechanical clamping solution: This solution uses a multi-jaw linkage clamping mechanism to clamp and fix the crystal at multiple points. Although this solution can reduce the chipping rate from 12% to about 5%, the mechanical structure usually contains up to 32 precision transmission components, and the manufacturing cost is as high as 80,000 to 120,000 yuan per set, which is more than 5 times higher than that of ordinary clamps. The clamping adjustment requires calibration with 3 sets of dial indicators, and the clamping time for a single crystal is 40 to 60 minutes, which is 70% less efficient than traditional clamping. Moreover, the clamping force must be strictly controlled within the range of 5-8N. If it exceeds 8N, it will produce indentation on the crystal surface (indentation depth ≥3μm), and if it is less than 5N, it cannot be effectively fixed, resulting in an extremely low operational error tolerance.

[0005] 2. Adhesive Fixing Solution: Epoxy adhesives are used to bond and fix the guide frame or glass protective sheet to the crystal. This solution requires a special low-temperature curing adhesive (priced at 800-1200 RMB / kg). Each 100mm×100mm crystal requires 2-3g of adhesive, increasing the cost of auxiliary materials by 1.6-3.6 RMB / piece. After bonding, it needs to be cured at 60℃ for 2 hours, increasing the time required for auxiliary processes. After cutting, it needs to be soaked in acetone solution for 4-6 hours to remove adhesive residue. During the soaking process, the surface gloss of the crystal will decrease by 5-8%, requiring an additional polishing process, further increasing processing costs and reducing overall processing efficiency by more than 40%.

[0006] 3. Equipment Retrofit Solutions: Such as vibration-assisted cutting (adding a high-frequency vibration device, vibration frequency 20-50kHz) and laser-assisted multi-wire cutting (equipped with a 1064nm pulsed laser). These solutions require significant modifications to existing cutting equipment. The retrofit cost for vibration-assisted cutting is approximately 150,000-200,000 RMB per unit, while the purchase cost of laser-assisted cutting equipment is as high as 800,000-1,200,000 RMB per unit, which is 4-6 times that of ordinary multi-wire cutting equipment. Moreover, the maintenance cost of the equipment increases significantly after the retrofit, with monthly maintenance costs increasing by 5,000-8,000 RMB, and the equipment failure rate increasing from 3% to 8%. This makes it difficult to popularize in small and medium-sized production enterprises with an annual production capacity of less than 50,000 pieces.

[0007] 4. Existing Protective Material Selection: Traditional protective materials mainly include quartz glass (3mm thick, 200-300 RMB / piece) and stainless steel sheets (0.5mm thick, 50-80 RMB / piece). Quartz glass is expensive, increasing the cost of a single crystal protective material by 200-300 RMB. Stainless steel sheets have extremely poor transparency, with a light transmittance of less than 10%, making it impossible to observe the contact state between the cutting line and the crystal. When the tension fluctuation of the cutting line exceeds 2N, it cannot be detected in time, easily leading to large-area edge chipping, with such anomalies resulting in a scrap rate of 10-15%. In addition, neither material has elastic cushioning, and their edge chipping prevention effect is limited, only reducing the chipping rate from 12% to 8-9%.

[0008] In summary, existing technical solutions all suffer from drawbacks such as limited anti-chipping effects, high processing costs, complex operation, or large equipment investments, making it difficult to meet the comprehensive requirements of precision, efficiency, and cost in high-end brittle crystal processing. According to industry survey data, yttrium vanadate crystal processing companies currently suffer annual economic losses exceeding 200 million yuan due to chipping issues.

[0009] Therefore, there is an urgent need to develop a low-cost (protective material cost ≤ 50 yuan / piece), easy-to-operate (single crystal clamping time ≤ 10 minutes), equipment-free, and anti-chipping effect (chipping rate ≤ 2%) crystal multi-wire cutting technology to address the shortcomings of existing technologies and promote the technological upgrading of the brittle crystal precision machining industry. Summary of the Invention

[0010] To address the problems of existing technologies, the purpose of this invention is to provide a method for preventing edge chipping in multi-wire cutting of crystal materials. By optimizing the selection of protective materials, improving the fixing method, and precisely controlling processing parameters, the following objectives are achieved: 1. The edge chipping rate of yttrium vanadate crystal cutting is reduced from the traditional 8-12% to below 1%, with a chipping size ≤10μm; 2. The product yield is increased from 92-95% to over 99%; 3. The overall processing cost per crystal is reduced by more than 60%; 4. The time for clamping and auxiliary processes of a single crystal is ≤15 minutes; 5. No structural modifications to existing multi-wire cutting equipment are required, and it is compatible with mainstream multi-wire cutting equipment such as the DSQ-600 and HLX-800, thereby significantly reducing processing costs and operational complexity while improving processing quality and efficiency, meeting the mass production needs of high-end brittle crystals.

[0011] To achieve the above objectives, the present invention is implemented according to the following technical solution: A method for preventing edge chipping in multi-wire cut crystal materials includes the following steps: S1. Prepare the crystal to be cut: Select crystals with dimensional tolerance within ±0.1mm and no obvious scratches on the surface (scratch depth ≤2μm) as the processing object. Clean the surface of the crystal to be cut to ensure the cleanliness of the surface of the crystal to be cut. S2. Selection of protective material: Select acrylic glass (PMMA) with double-sided polishing as the protective material. The surface size of the acrylic glass is larger than the surface size of the crystal to be cut. S3. Fixing and Protective Material: Acrylic glass is tightly bonded and fixed to the surface of the crystal to be cut using an adsorption method; S4. Multi-wire cutting operation: The crystal with acrylic glass fixed on it is clamped into the multi-wire cutting equipment, and the cutting parameters are set for cutting. During the cutting process, the cutting progress and the state of the crystal can be observed in real time through the acrylic glass. S5. Post-processing: After cutting, release the adsorption fixation in the reverse order of fixation (vacuum adsorption requires slow depressurization, with a depressurization rate ≤0.02MPa / s; electrostatic adsorption requires discharge to a voltage ≤50V first) to avoid crystal damage due to sudden pressure changes; after removing the acrylic glass, clean both the acrylic glass and the cut crystal.

[0012] Preferably, in step S1, the specific steps of the cleaning process are as follows: First, use high-pressure air (pressure 0.4-0.6MPa) to blow away the floating dust on the surface of the crystal to be cut, with a blowing distance controlled at 15-20cm and a blowing time of 20-30s; then, use a lint-free cloth (Class 100) soaked in anhydrous ethanol (purity ≥99.7%) to wipe the surface of the crystal to be cut in one direction, wiping 3-5 times; finally, use deionized water (resistivity ≥18.2MΩ·cm) to rinse the surface of the crystal to be cut, with a rinsing flow rate of 5-8L / min and a rinsing time of 1-2min; then, place the crystal in a clean oven (cleanliness Class 1000) and dry it at 60±5℃ for 30-40min to ensure that the removal rate of dust, oil and other impurities on the surface of the crystal to be cut is ≥99%, and the surface roughness Ra≤0.2μm.

[0013] Preferably, in step S2, the acrylic glass has the following parameters: density of 1.18-1.20 g / cm³. 3 Tensile strength ≥75MPa, elongation at break ≥2.5%, light transmittance ≥92% (at a wavelength of 550nm), Vickers hardness 160-180HV, thickness 1-5mm, thickness tolerance ±0.05mm, surface roughness Ra≤0.8μm, flatness ≤0.01mm / 100mm (ensuring transparency and surface flatness to avoid uneven stress distribution due to uneven thickness or surface irregularities).

[0014] Preferably, in step S2, the acrylic glass is customized according to the size of the crystal to be cut, and the surface size of the acrylic glass is 5-10mm larger than the surface size of the crystal to be cut. 2 This facilitates subsequent adsorption and fixation operations.

[0015] Preferably, in step S3, the adsorption method is vacuum adsorption or electrostatic adsorption, and the adsorption force is controlled at 0.05-0.3MPa to ensure that the bonding gap is ≤2μm.

[0016] It should be noted that the adsorption device can be a vacuum adsorption platform or an electrostatic adsorption platform (selected according to the conductivity characteristics of the crystal). If vacuum adsorption is used, the vacuum adsorption platform needs to be equipped with uniformly distributed adsorption holes (hole diameter 0.5-1mm, hole spacing 5-8mm). After starting the vacuum pump, the adsorption force should be controlled at 0.05-0.3MPa. During the adsorption process, the adsorption force should be monitored in real time by a pressure sensor, with a fluctuation range of ≤±0.02MPa. If electrostatic adsorption is used, the voltage of the electrostatic adsorption platform should be controlled at 5-15kV, and the adsorption force should be controlled at 0.08-0.25MPa to ensure that the acrylic glass is tightly bonded to the crystal surface, with a bonding gap of ≤2μm and no air bubbles or impurities remaining. After fixing, the flatness of the acrylic glass surface should be checked with a laser rangefinder to ensure that the parallelism with the crystal surface is ≤0.03mm / 100mm.

[0017] Preferably, in step S4, a flexible positioning block is used to clamp the crystal with the fixed acrylic glass onto the multi-wire cutting equipment. The flexible positioning block is made of polyurethane and has a Shore hardness of 50-60D.

[0018] Preferably, in step S4, the cutting parameters are as follows: diamond wire is used for cutting, with a diameter of 0.14-0.16 mm; the wire speed is controlled at 1000-1500 m / min; the cutting tension is controlled at 8-12 N, with tension fluctuation ≤ ±0.5 N; and the cutting feed rate is controlled at 0.03-0.08 mm / min (adjusted according to the crystal thickness, preferably 0.05 mm / min for a thickness of 50 mm); the cutting fluid is polyethylene glycol-based cutting fluid (viscosity 20-30 mm at 25°C). 2 The flow rate is 50-80 L / min, the spray pressure is 0.3-0.5 MPa, and the spray angle is 30-45° with the cutting line.

[0019] It should be noted that during the cutting process, the transparency of acrylic glass, combined with an industrial camera (resolution ≥ 10 million pixels), allows for real-time observation of the cutting progress and crystal state. When the cutting line offset exceeds 0.05mm or microcracks (crack length ≥ 5μm) appear on the crystal edge, the equipment automatically adjusts the feed speed or pauses the cutting.

[0020] Preferably, in step S5, the cleaning process of the acrylic glass includes the following steps: first, ultrasonically clean the acrylic glass with a neutral detergent solution (pH 6-8) for 5-10 minutes (power 300-500W, frequency 40kHz), then rinse the acrylic glass with deionized water, and dry it for later use.

[0021] Preferably, in step S5, the cleaning process of the cut crystal includes the following steps: first, ultrasonically clean the cut crystal with cutting fluid cleaning agent (concentration 5-8%) for 10-15 minutes, then rinse the cut crystal with deionized water for 5 minutes, then wipe the cut crystal with anhydrous ethanol for 3 minutes, and finally place the cut crystal in an oven at 80±5℃ to dry for 60 minutes, and then test the quality of the cut surface of the crystal after drying.

[0022] It should be noted that acrylic glass is reusable with a lifespan of ≥50 uses. Before each use, only surface cleaning to remove cutting residue is required. During reuse, key parameters of the acrylic glass should be tested periodically: surface roughness and flatness should be checked every 10 uses. When the surface roughness Ra > 1.2μm or the flatness > 0.02mm / 100mm, it needs to be repolished (after polishing, the surface roughness can be restored to Ra ≤ 0.4μm). Repolished acrylic glass can continue to be used, further reducing material costs. Calculations show that after 50 reuses of a single piece of acrylic glass (3mm thick, 100mm×100mm), the cost per use is only 1.2-1.5 yuan, far lower than the cost per use of traditional quartz glass (200-300 yuan).

[0023] This method is applicable not only to yttrium vanadate crystals, but also to multi-wire cutting of other brittle crystalline materials such as sapphire, silicon carbide, and quartz. It is particularly suitable for high-end crystal cutting applications requiring extremely high precision (dimensional tolerance ≤ ±0.01 mm) and yield (≥98%), such as laser crystals and semiconductor substrates. Key parameters can be fine-tuned for different crystal materials: for sapphire crystals (Mohs hardness 9.0, fracture toughness 1.5-2.0 MPa·m¹),... / ²), the acrylic glass thickness is preferably 4mm, the adsorption force is controlled at 0.15-0.25MPa, the cutting line speed is 1300-1400m / min, and the cutting tension is 10-12N; for silicon carbide crystals (Mohs hardness 9.5, fracture toughness 2.0-2.5 MPa·m¹), / ²), the acrylic glass thickness is preferably 5mm, the adsorption force is controlled at 0.2-0.3MPa, the cutting line speed is 1100-1300m / min, and the cutting tension is 9-11N; for quartz crystal (Mohs hardness 7.0, fracture toughness 1.0-1.2 MPa·m¹), / ²), the acrylic glass thickness is preferably 2mm, the adsorption force is controlled at 0.08-0.18MPa, the cutting speed is 1200-1500m / min, and the cutting tension is 8-10N. After testing, the chipping rate of various crystals can be controlled below 1.5%, and the yield rate is ≥98.5%.

[0024] The beneficial effects of this invention are: (1) Significant anti-chipping effect: The polished acrylic glass has moderate elasticity (elastic modulus 3.0-3.5GPa), and its elastic deformation range is highly matched with the plastic deformation range of brittle crystals. It can provide uniform elastic support and stress buffer for the crystal edge during the cutting process, reducing the local stress peak generated by the cutting line from 200-300MPa to 80-120MPa, effectively inhibiting crack initiation and propagation. Through comparative testing, 100 pieces of yttrium vanadate crystals with specifications of 100mm×100mm×50mm were selected. 50 pieces were cut using the method of this invention, and 50 pieces were cut using the traditional unprotected method. The results showed that the chipping rate of the traditional method was 10.2%, and the average chipping size was 35μm; the chipping rate of the method of this invention was only 0.8%, and the average chipping size was 4μm. The chipping rate was reduced by 92.2%, and the chipping size was reduced by 88.6%, which fully meets the stringent requirements for chipping in high-end crystal processing.

[0025] (2) Significantly improved yield: The solution to the edge chipping problem directly improves the dimensional accuracy and surface quality of the crystal cutting surface. According to the test results of a third-party testing institution, the flatness of the yttrium vanadate crystals cut using the method of this invention can reach 0.003mm / 100mm, which is 40% higher than that of the traditional method; the dimensional tolerance is controlled within ±0.008mm, which is 40% smaller than that of the traditional method; and the surface roughness Ra=0.15μm, which is 62.5% lower than that of the traditional method. A batch test of 500 crystals was conducted. The yield rate of the traditional method was 93.6%, while the yield rate of the method of this invention reached 99.4%, which is 5.8 percentage points higher. Based on an annual production capacity of 100,000 pieces, this can reduce the number of defective products by 3,200 pieces per year and reduce economic losses by more than 6.4 million yuan.

[0026] (3) Significantly reduced processing costs: The cost reduction is mainly reflected in three aspects: First, material costs. The unit price of acrylic glass is only 30-50 yuan / piece (3mm thick, 100mm×100mm specification), which is 1 / 5-1 / 3 of that of quartz glass, and it can be reused more than 50 times, with a single material cost of only 1.2-1.5 yuan; Second, auxiliary costs. No bonding materials or special fixtures are required, and the auxiliary material cost per crystal is reduced from the traditional 20-30 yuan to 2-3 yuan; Third, labor costs. The clamping and auxiliary process time is shortened from the traditional 40-60 minutes to 10-15 minutes, and the labor cost per crystal is reduced from 8-12 yuan to 2-3 yuan. In summary, the processing cost of a single yttrium vanadate crystal is reduced from the traditional 120-150 yuan to 40-50 yuan, and the overall processing cost is reduced by 60-70%.

[0027] (4) Simple operation: No modification is required to the existing multi-wire cutting equipment. Only a simple adsorption device needs to be added (the cost of the vacuum adsorption device is 3,000-5,000 yuan / set, and the cost of the electrostatic adsorption device is 5,000-8,000 yuan / set). The adsorption device can be directly installed on the equipment workbench, and the installation time is ≤2 hours. The clamping and disassembly processes are standardized operations. Operators can master them after 1-2 hours of training. The operation process can be summarized as "cleaning-adsorption-clamping-cutting-disassembly-re-cleaning". There are no complicated adjustment steps, the operation error tolerance is high, and the product scrap rate caused by operation error can be effectively reduced (from the traditional 5% to less than 1%).

[0028] (5) Convenient observation: Acrylic glass has a light transmittance of ≥92%, which is much higher than that of stainless steel sheets (light transmittance <10%), enabling real-time visualization of the cutting process. Combined with an industrial camera and image analysis system, the operating status of the cutting line (line vibration amplitude ≤0.03mm), cutting depth (error ≤0.02mm), and micro-cracks at the crystal edges can be monitored in real time. When an abnormality is detected, cutting parameters can be adjusted promptly (e.g., reducing the feed speed by 20-30%) or cutting can be paused. Tests have shown that after adopting visual monitoring, the product scrap rate due to cutting abnormalities has decreased from the traditional 10-15% to below 2%, further improving processing stability.

[0029] (6) Strong equipment compatibility: The method of this invention is compatible with various mainstream multi-wire cutting equipment on the market, including domestic DSQ-600 and HLX-800, and imported Japanese DISCO DFD651 and Swiss MECOF M5 models. Through testing on different models of equipment, one of each of the above four models was selected, and 20 pieces of yttrium vanadate crystals were cut by each equipment. The results showed that the chipping rate of the four equipment using the method of this invention was between 0.6% and 1.0%, and the yield rate was ≥99.2%, with no significant difference. This indicates that the method of this invention has wide equipment compatibility and can be promoted and applied without enterprises replacing existing equipment, thus reducing the technical upgrade costs of enterprises. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0032] The present invention will now be clearly described with reference to the accompanying drawings and specific embodiments. This description is merely illustrative and is not intended to limit the scope of the invention. Any modifications, equivalent substitutions, or improvements made by those skilled in the art based on the embodiments of the present invention without inventive effort to obtain all other embodiments should be included within the scope of protection of the present invention.

[0033] Example 1 like Figure 1 As shown, this embodiment of the invention provides a method for preventing edge chipping in multi-wire cut crystal materials, including the following steps: S1. Prepare the crystal to be cut: Select 100 pieces of yttrium vanadate crystals with a size of 100mm×100mm×50mm (purity ≥99.99%, crystal orientation

[100] ) and process them according to the three-level cleaning process: first blow them with 0.5MPa high-pressure air for 25 seconds, then wipe them 4 times with a Class 100 clean cloth with 99.8% anhydrous ethanol, and finally rinse them with 18.2MΩ·cm deionized water for 1.5 minutes. Place them in a Class 1000 clean oven and dry them at 60℃ for 35 minutes. After drying, the surface impurity removal rate of the crystal to be cut is 99.5%, and the surface roughness Ra=0.18μm.

[0034] S2. Selection of protective material: 3mm thick acrylic glass was selected, with double-sided polishing. The material parameters were tested as follows: density 1.19g / cm³, tensile strength 78MPa, elongation at break 2.8%, light transmittance 93% (at 550nm), Vickers hardness 172HV; surface roughness Ra=0.4μm, thickness tolerance ±0.04mm, flatness 0.008mm / 100mm; it was cut to a size of 105mm×105mm (5mm larger than the surface to be cut of the crystal), and the cut edges were burr-free (burr height ≤1μm).

[0035] S3. Fixing and Protecting Material: Using a vacuum adsorption platform (adsorption pore diameter 0.8mm, pore spacing 6mm), acrylic glass is placed over the yttrium vanadate crystal surface to be cut, ensuring that the edges of the acrylic glass extend evenly beyond the crystal edges. The vacuum pump is started, and the adsorption force is controlled at 0.15MPa via a pressure sensor, with a fluctuation of ±0.01MPa. After adsorption, the flatness of the acrylic glass surface is checked using a laser rangefinder; the parallelism is 0.02mm / 100mm, the bonding gap is 1.5μm, and there are no air bubbles or impurities remaining.

[0036] S4. Multi-wire cutting operation: The crystal was clamped onto the DSQ-600 multi-wire cutting equipment. A 0.15mm diameter diamond wire was selected, and the cutting speed was set to 1200m / min, cutting tension to 10N (tension fluctuation ±0.3N), and cutting feed rate to 0.05mm / min. A polyethylene glycol-based cutting fluid (viscosity 25mm² / s, at 25℃) was used, with a flow rate of 65L / min, a spray pressure of 0.4MPa, and a spray angle of 35°. During the cutting process, the cutting progress and crystal edge status were recorded in real-time using an industrial camera (12 megapixels), with the cutting progress recorded every 5 minutes. No cutting line deviation or microcracks were found.

[0037] S5. Post-processing: After cutting is completed (total cutting time is 1000 minutes), slowly depressurize at a rate of 0.01 MPa / s, turn off the vacuum pump, and remove the acrylic glass; place the acrylic glass in a neutral detergent (pH 7) solution for ultrasonic cleaning for 8 minutes (power 400W, frequency 40kHz), rinse with deionized water for 5 minutes, and dry at 60℃ for 30 minutes before use; after cutting, the crystal is ultrasonically cleaned with 6% concentration cutting fluid cleaner for 12 minutes, rinsed with deionized water for 5 minutes, dehydrated with anhydrous ethanol for 3 minutes, and dried in an oven at 80℃ for 60 minutes.

[0038] According to the testing results of 100 yttrium vanadate crystals in this embodiment, as determined by a third-party testing agency: 99 crystals had chipping dimensions ≤ 5 μm, and only one crystal had a chipping dimension of 6 μm, resulting in a chipping rate of 0.8%; the flatness of the cut surface was 0.003 mm / 100 mm, the dimensional tolerance was ±0.007 mm, and the surface roughness Ra = 0.14 μm; all crystals met the processing standards for high-end laser crystals, with a yield rate of 99.6%. Compared to traditional unprotected cutting (selecting 100 crystals from the same batch, the chipping rate was 10.5%, and the yield rate was 93.0%), the chipping rate was reduced by 92.4%, and the yield rate was increased by 6.6 percentage points; the processing cost per crystal was calculated as follows: material cost 1.3 yuan, auxiliary material cost 2.5 yuan, labor cost 2.2 yuan, equipment depreciation and energy consumption cost 34 yuan, and the comprehensive processing cost was 40 yuan, which is 68% lower than the traditional method (125 yuan / crystal). Furthermore, no scrapped products were found due to operational errors or equipment malfunctions during the cutting process, significantly improving processing stability.

[0039] Example 2 This embodiment compares the anti-chipping effect of acrylic glass with different thicknesses. To determine the impact of acrylic glass thickness on the anti-chipping effect, surface-polished acrylic glass with thicknesses of 1mm, 3mm, and 5mm (other parameters are the same: double-sided polishing, Ra=0.4μm, size 105mm×105mm, and material parameters are the same) was selected for each group. Thirty yttrium vanadate crystals with dimensions of 100mm×100mm×50mm were selected for each group. The method of Example 1 was used to cut the yttrium vanadate crystals (except for the acrylic glass thickness, other cutting parameters are the same: vacuum adsorption force 0.15MPa, cutting line speed 1200m / min, cutting tension 10N, feed rate 0.05mm / min). The chipping rate, processing stability (based on the probability of micro-cracks appearing at the crystal edge during cutting), and material cost of each group were tested. The test results are shown in the table below.

[0040] The specific performance of each group is as follows: Thickness 1mm: chipping rate 1.2%, average chipping size 5.2μm; two crystals developed microcracks during cutting (microcrack length ≤8μm), with a microcrack occurrence probability of 8.3%; due to the thinness, the acrylic glass underwent slight deformation under the pressure of the cutting line (maximum deformation 0.03mm), resulting in uneven local support and generally poor processing stability; however, the material cost is the lowest, at only 20 yuan per piece.

[0041] Thickness 3mm: chipping rate 0.7%, average chipping size 4.1μm; only 1 crystal showed micro-cracks (crack length ≤5μm), micro-crack occurrence probability 2.1%; acrylic glass showed no obvious deformation (deformation ≤0.01mm), good uniformity of support for crystal edges, high observation clarity (light transmittance 93%), clear monitoring of the entire cutting process, and optimal processing stability; moderate material cost, 35 yuan per piece.

[0042] Thickness 5mm: chipping rate 0.9%, average chipping size 4.5μm; one crystal had a microcrack (crack length ≤6μm), and the probability of microcracks was 3.5%; the acrylic glass had good stability and no deformation; however, due to its large thickness, the material cost was the highest (50 yuan per piece), and the viewing angle was slightly affected (the light transmittance was still 92%, but the light refraction caused the edge observation clarity to decrease by about 10%).

[0043] Conclusion: Acrylic glass thicknesses of 1-5mm can achieve good edge chipping prevention (chipping rate ≤1.2%), but considering edge chipping prevention, processing stability, material cost, and ease of observation, 3mm thickness is the optimal choice. At this thickness, the chipping rate is lowest, processing stability is best, material cost is moderate, and clear observation of the cutting process is guaranteed, thus maximizing the balance between processing quality, efficiency, and cost.

[0044] Example 3 This embodiment tests the adaptability of different adsorption forces. To determine the impact of adsorption force on edge-resistant performance and ease of operation, 3mm thick acrylic glass (parameters same as in Example 2) was used. Adsorption forces were set at three gradients: 0.05MPa, 0.15MPa, and 0.3MPa. For each group, 30 yttrium vanadate crystals with dimensions of 100mm×100mm×50mm were selected. The method of Example 1 (except for adsorption force, all other cutting parameters were the same: cutting line speed 1200m / min, cutting tension 10N, feed rate 0.05mm / min) was used to cut the yttrium vanadate crystals. The edge-resistant rate, bonding gap, crystal surface damage rate, and disassembly difficulty were tested for each group. The test results are shown in the table below:

[0045] The specific performance of each group is as follows: Adsorption force 0.05MPa: edge breakage rate 1.5%, average edge breakage size 6.1μm; bonding gap 3.2μm, some areas have micro bubbles (3-5 bubbles / piece, bubble diameter ≤20μm), resulting in insufficient local support and general edge breakage prevention effect; however, the crystal surface is undamaged, disassembly takes only 2 minutes, and the operation is convenient.

[0046] Adsorption force 0.15MPa; edge breakage rate 0.6%, average edge breakage size 3.8μm; bonding gap 1.5μm, no bubbles or impurities remaining, acrylic glass and crystal surface are tightly bonded, providing uniform support for crystal edges and the best edge breakage prevention effect; crystal surface is undamaged, disassembly can be completed by slowly releasing pressure for 3 minutes, the disassembly process is smooth and the operation is the most convenient.

[0047] Adsorption force 0.3MPa: edge breakage rate 0.7%, average edge breakage size 4.2μm; bonding gap 1.2μm, stable bonding, good edge breakage prevention effect; however, indentations appeared on the surface of 2 crystals (indentation depth 3-5μm), crystal surface damage rate 2.5%; during disassembly, the pressure relief rate must be strictly controlled (≤0.01MPa / s), otherwise it is easy to cause impact damage to the crystal edge, disassembly takes up to 8 minutes, operation is difficult and inconvenient.

[0048] Conclusion: The optimal adsorption force (0.1-0.2 MPa) provides the best balance between edge chipping prevention and ease of operation. Within this range, the adsorption force ensures a tight bond between the acrylic glass and the crystal surface (gap ≤ 2 μm), effectively providing elastic support and keeping the edge chipping rate below 1%. Simultaneously, it avoids damage to the crystal surface caused by excessive adsorption force, while allowing for simple and quick disassembly (≤ 4 minutes), eliminating the need for complex procedures and significantly improving processing efficiency. The optimal adsorption force parameter is 0.15 MPa, achieving a perfect balance between edge chipping prevention and ease of operation.

[0049] This invention breaks away from the conventional mindset of rigid support for traditional protective materials, and for the first time applies polished acrylic glass to the edge protection of crystal multi-wire cutting through an adsorption method. It utilizes the moderate elasticity of acrylic glass (elastic modulus 3.0-3.5 GPa) to achieve stress buffering, high light transmittance (≥92%) to enable real-time visual monitoring, and low cost (30-50 RMB / piece) and reusability (≥50 times) to reduce processing costs. This invention solves the core defects of existing technologies, such as poor edge protection effect, high cost, and complex operation.

[0050] Secondly, through extensive experiments, the optimal parameter combination was determined to ensure anti-chipping effect and processing stability: First, acrylic glass parameters: thickness 1-5mm (optimal 3mm), surface roughness Ra≤0.8μm (optimal Ra≤0.4μm). This parameter combination ensures uniform elastic support and clear observation. Second, adhesion force parameters: controlled at 0.05-0.3MPa (optimal 0.1-0.2MPa), ensuring tight adhesion and no crystal damage. Third, cutting parameters: cutting line speed 1000-1500m / min, cutting tension 8-12N. These parameters match the protective characteristics of acrylic glass and effectively reduce cutting stress. The synergistic effect of these key parameters is the core guarantee for achieving a chipping rate ≤1% and a yield rate ≥99%.

[0051] Furthermore, the core advantage of this method lies in its compatibility with mainstream multi-wire cutting equipment, requiring no equipment modification. It can be widely applied to the precision cutting of various brittle crystal materials such as yttrium vanadate, sapphire, silicon carbide, and quartz. It is particularly suitable for small to medium-sized crystal processing enterprises with an annual production capacity of 5,000-50,000 pieces, as well as high-end laser crystal and semiconductor substrate processing scenarios with stringent requirements for processing accuracy and cost. Pilot applications by multiple companies have demonstrated that this method can be quickly implemented in existing production lines (implementation cycle ≤ 3 days) without requiring additional production space or specialized equipment, indicating broad prospects for widespread application.

[0052] Finally, this invention forms a complete technical system through material selection optimization, precise parameter matching, and standardized operation procedures. Among these, core technologies such as the elastic matching law between acrylic glass and different brittle crystals, and the synergistic control method of adsorption force and cutting stress, require extensive experimental data accumulation to form a proprietary technical parameter library, making it difficult for competitors to quickly replicate. Furthermore, this method allows for rapid parameter adjustment based on different crystal materials, possessing excellent technical scalability and further solidifying the technological barrier.

[0053] The embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preventing edge chipping in multi-wire cut crystal materials, characterized in that: Includes the following steps: S1. Prepare the crystal to be cut: Clean the surface of the crystal to be cut to ensure the cleanliness of the surface. S2. Select protective material: Select acrylic glass with double-sided polishing as the protective material. The surface size of the acrylic glass is larger than the surface size of the crystal to be cut. S3. Fixing and Protective Material: Acrylic glass is tightly bonded and fixed to the surface of the crystal to be cut using an adsorption method; S4. Multi-wire cutting operation: The crystal with acrylic glass fixed on it is clamped into the multi-wire cutting equipment, and the cutting parameters are set for cutting. During the cutting process, the cutting progress and the state of the crystal can be observed in real time through the acrylic glass. S5. Post-processing: After cutting, remove the adsorption and acrylic glass, and clean the acrylic glass and the cut crystal respectively.

2. The method for preventing edge chipping of multi-wire cut crystal materials according to claim 1, characterized in that: In step S1, the specific cleaning steps are as follows: First, use high-pressure air to blow away the floating dust on the surface of the crystal to be cut, with the blowing distance controlled at 15-20cm and the blowing time at 20-30s; then, use a lint-free cloth soaked in anhydrous ethanol to wipe the surface of the crystal to be cut in one direction, wiping 3-5 times; finally, rinse the surface of the crystal to be cut with deionized water, with a rinsing flow rate of 5-8L / min and a rinsing time of 1-2min; after that, place the crystal in a clean oven and dry it at 60±5℃ for 30-40min.

3. The method for preventing edge chipping of multi-wire cut crystal materials according to claim 1, characterized in that: In step S2, the acrylic glass has the following parameters: density of 1.18-1.20 g / cm³. 3 Tensile strength ≥75MPa, elongation at break ≥2.5%, light transmittance ≥92%, Vickers hardness 160-180HV, thickness 1-5mm, thickness tolerance ±0.05mm, surface roughness Ra≤0.8μm, flatness ≤0.01mm / 100mm.

4. The method for preventing edge chipping of multi-wire cut crystal materials according to claim 3, characterized in that: In step S2, the surface size of the acrylic glass is 5-10 mm larger than the surface size of the crystal to be cut. 2 .

5. The method for preventing edge chipping of multi-wire cut crystal materials according to claim 1, characterized in that: In step S3, the adsorption method is vacuum adsorption or electrostatic adsorption, and the adsorption force is controlled at 0.05-0.3MPa to ensure that the bonding gap is ≤2μm.

6. The method for preventing edge chipping of multi-wire cut crystal materials according to claim 1, characterized in that: In step S4, a flexible positioning block is used to clamp the crystal with the fixed acrylic glass onto the multi-wire cutting equipment. The flexible positioning block is made of polyurethane and has a Shore hardness of 50-60D.

7. The method for preventing edge chipping of multi-wire cut crystal materials according to claim 6, characterized in that: In step S4, the cutting parameters are as follows: diamond wire is used for cutting, with a diameter of 0.14-0.16 mm, the wire speed is controlled at 1000-1500 m / min, the cutting tension is controlled at 8-12 N, the tension fluctuation is ≤±0.5 N, and the cutting feed speed is controlled at 0.03-0.08 mm / min; polyethylene glycol-based cutting fluid is used, with a flow rate of 50-80 L / min, a spray pressure of 0.3-0.5 MPa, and a spray angle of 30-45° with the cutting line.

8. The method for preventing edge chipping of multi-wire cut crystal materials according to claim 1, characterized in that: In step S5, the cleaning process for acrylic glass includes the following steps: first, ultrasonically clean the acrylic glass with a neutral detergent solution for 5-10 minutes, then rinse the acrylic glass with deionized water, and dry it for later use.

9. The method for preventing edge chipping of multi-wire cut crystal materials according to claim 8, characterized in that: In step S5, the cleaning process of the cut crystal includes the following steps: first, ultrasonically clean the cut crystal with cutting fluid cleaner for 10-15 minutes, then rinse the cut crystal with deionized water for 5 minutes, then wipe the cut crystal with anhydrous ethanol for 3 minutes, and finally place the cut crystal in an oven at 80±5℃ to dry for 60 minutes. After drying, the quality of the cut surface of the crystal is tested.

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