Method for judging mortar failure in multi-line cutting of silicon carbide crystal ingot

Abstract

The invention discloses a method for judging failure of mortar in multi-line cutting of silicon carbide crystal ingots, and belongs to the technical field of multi-line cutting processing of the silicon carbide crystal ingots. According to the method, the comprehensive failure score is calculated by adopting the weighted summation method on the basis of the density, the viscosity and the change rate of the diamond abrasive particle rounding proportion of the diamond abrasive particle cutting mortar in the cutting process, whether the comprehensive failure score is larger than or equal to the failure threshold value or not is judged, and online real-time judgment of the state of the cutting mortar is achieved. By accurately judging the mortar replacement time, the best matching of the cutting mortar performance and the cutting process parameters is kept, the silicon carbide crystal ingot cutting efficiency and the surface type quality are improved, the quality problem caused by continuous use of invalid mortar is prevented, the utilization rate of diamond abrasive particles is improved, and the waste of high-cost diamond abrasive particles is reduced; the problem of hysteresis caused by judging the performance of the cutting mortar by testing the quality parameters of the cutting blade after the silicon carbide crystal ingot is cut in the traditional method is solved.

Description

Technical Field

[0001] This invention belongs to the field of multi-wire cutting technology for silicon carbide ingots, and specifically relates to a method for judging the failure of multi-wire cutting slurry for silicon carbide ingots. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Currently, diamond abrasive cutting slurry is a key consumable for achieving efficient cutting in multi-wire dicing of silicon carbide ingots. Commercial silicon carbide substrates have diameters ranging from 150 mm to 300 mm, with a single cutting process lasting 100-200 hours. The performance and stability of the slurry directly affect the cutting quality. Existing technologies typically rely on post-cut wafer morphology inspection (such as curvature, warpage, total thickness deviation, and roughness) to indirectly determine slurry failure. This method suffers from significant lag: if the slurry fails during cutting, its performance will be mismatched with the multi-wire dicing machine's feed rate, wire tension, and wire speed, leading to wafer surface damage, increased wire marks, and even edge chipping or cracking, significantly increasing the difficulty of subsequent grinding and polishing, and raising production costs.

[0004] On the other hand, the high cost of diamond abrasive grains means that prematurely replacing cutting mortar that is not yet fully degraded wastes resources, while delayed replacement risks scrap. Achieving a precise balance between mortar utilization and cutting quality is the core challenge in reducing the cost of silicon carbide cutting. Therefore, there is an urgent need to develop a failure assessment method that can determine the mortar status in real time and quickly during the cutting process, in order to simultaneously achieve quality assurance and cost optimization. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for determining the failure of multi-wire cutting slurry for silicon carbide ingots. This invention is based on the rate of change of density, viscosity, and diamond abrasive grain roundness ratio of the cutting slurry compared to the initial mix ratio during the cutting process. A weighted summation method is used to calculate a comprehensive failure score S, determining whether the cutting slurry has failed and allowing for timely replacement with new slurry. The determination method provided by this invention has the advantages of being fast, simple, and highly accurate.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: The first aspect of the present invention provides a method for determining the failure of multi-wire cutting slurry for silicon carbide ingots, comprising: Obtain the density of the cutting mortar and calculate the density change rate; Obtain the viscosity of the cutting mortar and calculate the viscosity change rate; Obtain the roundness ratio of diamond abrasive; The comprehensive failure score was calculated using a weighted summation method based on the density change rate, viscosity change rate, and diamond abrasive rounding ratio. Determine whether the comprehensive failure score is greater than or equal to the failure threshold. If so, determine that the cutting mortar has failed.

[0007] In some embodiments of the present invention, the sampling frequency of the cutting mortar is as follows: sampling at an interval of 12-24 hours in the early stage, sampling at an interval of 6-12 hours in the middle stage, and sampling at an interval of 3-6 hours in the late stage.

[0008] In some embodiments of the present invention, obtaining the density of the cutting mortar includes: Take 20-40 mL of cutting mortar, weigh it, and then calculate the density of the cutting mortar using the density calculation formula.

[0009] In some embodiments of the present invention, obtaining the viscosity of the cutting mortar includes: Take 20-40 mL of cutting mortar and test its viscosity at 20-50℃ to obtain the viscosity of the cutting mortar.

[0010] In some embodiments of the present invention, the density change rate is the rate of change between the density of the cutting mortar to be tested and the initial density of the cutting mortar; The viscosity change rate is the rate of change between the viscosity of the cutting mortar to be tested and the initial viscosity of the cutting mortar.

[0011] In some embodiments of the present invention, obtaining the roundness ratio of the diamond abrasive includes: Obtain cutting slurry, dry it, observe the morphology of diamond abrasive and calculate the roundness ratio of diamond abrasive. The number of diamond abrasive morphology samples ranged from 20 to 80.

[0012] In some embodiments of the present invention, the formula for calculating the comprehensive failure score S using the weighted summation method is as follows: ; Where W is the normalized weight coefficient, W1 is the density change rate weight, W2 is the viscosity change rate weight, and W3 is the diamond abrasive grain rounding ratio weight; I is an indicator function, which takes the value 1 when the condition is met and 0 otherwise. The condition for I1 is: density change rate ≥ density failure threshold, the condition for I2 is: viscosity change rate ≥ viscosity failure threshold, and the condition for I3 is: diamond abrasive grain rounding ratio ≥ diamond abrasive grain rounding ratio failure threshold.

[0013] In some embodiments of the present invention, W1 takes the value of 0.2-0.4, W2 takes the value of 0.2-0.4, and W3 takes the value of 0.3-0.5.

[0014] In some embodiments of the present invention, the density failure threshold is 20-50%, the viscosity failure threshold is 100-200%, and the diamond abrasive roundness ratio failure threshold is 50%-80%.

[0015] In some embodiments of the present invention, the failure threshold is the average of the comprehensive failure scores of multiple critical failure cutting mortars.

[0016] The beneficial effects of this invention are as follows: This invention provides a method for judging the failure of diamond abrasive cutting slurry in silicon carbide ingots. Based on the rate of change of density, viscosity, and diamond abrasive roundness ratio of the diamond abrasive cutting slurry during the cutting process, a weighted summation method is used to calculate a comprehensive failure score. The method then determines whether the comprehensive failure score is greater than or equal to a failure threshold, achieving online real-time judgment of the cutting slurry state. By proactively intervening in the timing of slurry replacement during the cutting process, the method ensures that the cutting quality continuously meets the requirements of geometric parameters such as bow and warp, significantly reducing surface marks and damage. This lays a high-yield foundation for subsequent grinding and polishing processes, completely solving the lag problem of traditional offline detection after cutting, and avoiding irreversible damage such as wafer surface defects, edge chipping, and cracking caused by the continued use of failed slurry. Meanwhile, this invention uses multi-parameter weighted scoring to accurately quantify the critical failure point of the mortar, preventing premature replacement that would waste high-cost diamond abrasive grains and optimizing diamond abrasive grain utilization. It also maintains the optimal match between mortar performance and cutting process parameters, improving silicon carbide ingot cutting efficiency and surface quality, avoiding the risk of scrap caused by delayed replacement, and simultaneously reducing abrasive grain wear and subsequent processing costs. This invention's physical parameter-based quantitative detection method does not require interruption of the cutting process or offline wafer cleaning, significantly improving judgment efficiency. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a flowchart illustrating the steps of the invention. Figure 2 A microscopic schematic diagram of multi-wire cutting of a silicon carbide ingot; Figure 3 Scanning electron microscope image of diamond abrasive grains; Figure 4 A transmission electron microscope image showing the sharp edges of diamond abrasive grains in cutting mortar; Figure 5 Transmission electron microscope image showing the blunt edges of diamond abrasive grains in cutting mortar. Detailed Implementation

[0019] To address the lag issue in traditional offline detection after cutting, this invention proposes a method for determining the failure of multi-wire cutting slurry in silicon carbide ingots.

[0020] like Figure 1 As shown, this invention provides a method for determining the failure of multi-wire cutting slurry for silicon carbide ingots, comprising: Obtain the density of the cutting mortar and calculate the density change rate; Obtain the viscosity of the cutting mortar and calculate the viscosity change rate; Obtain the roundness ratio of diamond abrasive; The comprehensive failure score was calculated using a weighted summation method based on the density change rate, viscosity change rate, and diamond abrasive rounding ratio. Determine whether the comprehensive failure score is greater than or equal to the failure threshold. If so, determine that the cutting mortar has failed.

[0021] This invention measures the changes in key parameters of the cutting mortar (density, viscosity, and diamond abrasive grain roundness ratio) during the cutting process and uses a weighted summation method to calculate a comprehensive failure score. This avoids the one-sidedness of single-parameter evaluation and enables rapid, real-time determination of whether the cutting mortar has failed. By accurately determining the timing of mortar replacement, it maintains the optimal match between the performance of the cutting mortar and the cutting process parameters, improving the cutting efficiency and surface quality of silicon carbide ingots, preventing quality problems caused by the continued use of failed mortar, and increasing the utilization rate of diamond abrasive grains, reducing the waste of high-cost diamond abrasive grains. It also solves the problem of increased costs caused by the lag in testing the quality parameters of the cutting disc to determine the performance of the cutting mortar after the silicon carbide ingot cutting is completed, which is a problem in traditional methods.

[0022] If the overall failure score is less than the failure threshold, the cutting mortar is determined to be not in failure and can be recycled.

[0023] In some embodiments of the present invention, the sampling frequency of the cutting mortar is as follows: for 6-inch (150 mm in diameter) silicon carbide ingots with a thickness of 20-30 mm, continuous cutting of 0-5 ingots is considered the early stage of use, with sampling intervals of 12-24 hours; continuous cutting of 5-10 ingots is considered the middle stage of use, with sampling intervals of 6-12 hours; and continuous cutting of more than 10 ingots is considered the late stage of use, with sampling intervals of 3-6 hours. As the usage time of the cutting mortar increases, the changes in its density, viscosity, and diamond abrasive grain roundness ratio compared to the initial mix gradually increase. However, the cutting mortar may also fail prematurely in the early or middle stages of use due to differences in cutting process parameters or the difficulty of processing ingots of different sizes. To ensure rapid, convenient, and accurate monitoring of the cutting mortar condition, the sampling frequency increases with usage time.

[0024] In some embodiments of the present invention, obtaining the density of the cutting mortar includes: Take 20-40 mL of cutting mortar, weigh it, and then calculate the density of the cutting mortar using the density calculation formula.

[0025] It should be noted that a graduated cylinder can be used for precise sampling, with an accuracy requirement of ±0.1 mL. When weighing, the balance accuracy requirement is ±0.1 g. The density calculation formula is as follows: Where m is mass (in g), V is volume (in mL), and ρ is density (in g / mL). The density of cutting debris (SiC particles, metal shavings, etc.) is usually higher than that of the base cutting oil. As the debris concentration increases, the overall density of the slurry increases, diamond abrasive grains tend to settle, resulting in decreased dispersion uniformity and suspension stability, leading to uneven abrasive grain distribution and exacerbating surface damage and scratches on the cutting disc.

[0026] In some embodiments of the present invention, obtaining the viscosity of the cutting mortar includes: Take 20-40 mL of cutting mortar and test its viscosity at 20-50℃ to obtain the viscosity of the cutting mortar.

[0027] It is understandable that a rotational viscometer is used to measure the viscosity of the cutting mortar at 20-50℃. Increased debris leads to a solid volume fraction exceeding the critical value, causing friction and collisions between particles, increasing fluid resistance. Poor chip removal and debris accumulation exacerbate surface microcracks and edge chipping. Uneven cutting resistance easily causes the cut surface to tilt or warp.

[0028] In some embodiments of the present invention, the density change rate is the rate of change between the density of the cutting mortar to be tested and the initial density of the cutting mortar; The viscosity change rate is the rate of change between the viscosity of the cutting mortar to be tested and the initial viscosity of the cutting mortar.

[0029] In some embodiments of the present invention, obtaining the roundness ratio of the diamond abrasive includes: Obtain cutting slurry, dry it, observe the morphology of diamond abrasive and calculate the roundness ratio of diamond abrasive. The number of diamond abrasive morphology samples ranged from 20 to 80.

[0030] Understandably, the cutting slurry is obtained, dripped onto a double copper mesh carbon film, dried, and then the morphology of the diamond abrasive is observed using a transmission electron microscope to calculate the abrasive roundness ratio.

[0031] Figure 3 The scanning electron microscope image shows diamond abrasive grains, clearly revealing the sharp edges of the grains. (Comparison) Figure 4 The transmission electron microscope image shown depicts the sharp edges of diamond abrasive grains in the cutting mortar. Figure 5The transmission electron microscope image shown depicts the blunt edges of diamond abrasive grains in the cutting slurry. As the cutting process progresses, the surface edges of the diamond abrasive grains gradually become blunt, losing their cutting ability and reducing the cutting speed. The blunted abrasive grains rely more on compression than cutting, exacerbating edge fragmentation of the cutting disc.

[0032] In some embodiments of the present invention, the formula for calculating the comprehensive failure score S using the weighted summation method is as follows: ; Where W is the normalized weight coefficient, W1 is the density change rate weight, W2 is the viscosity change rate weight, and W3 is the diamond abrasive grain rounding ratio weight; I is an indicator function, which takes the value 1 when the condition is met and 0 otherwise. The condition for I1 is: density change rate ≥ density failure threshold, the condition for I2 is: viscosity change rate ≥ viscosity failure threshold, and the condition for I3 is: diamond abrasive grain rounding ratio ≥ diamond abrasive grain rounding ratio failure threshold.

[0033] Figure 2 Microscopic schematic diagrams of multi-wire cutting of silicon carbide ingots and scanning electron microscope images of diamond abrasive grains illustrate the process of diamond cutting slurry during silicon carbide ingot cutting. Density, viscosity, and diamond abrasive grain roundness ratio reflect the physical properties, rheological characteristics, and abrasive grain state of the cutting slurry, respectively. Combining these three factors allows for a more comprehensive evaluation of the slurry's overall performance, avoiding the limitations of evaluating a single parameter. Weights W1, W2, and W3 are used to combine the influence of different parameters on slurry failure; for example, abrasive grain roundness ratio is more critical than viscosity changes. An indicator function transforms continuous parameter changes into a binary judgment (0 or 1), avoiding complex calculations and improving judgment efficiency.

[0034] In some embodiments of the present invention, W1 can be 0.2-0.4, W2 can be 0.2-0.4, and W3 can be 0.3-0.5. Weights are assigned using the coefficient of variation method based on data on the changes in density, viscosity, and diamond abrasive rounding ratio of multiple sets of cutting mortars at critical failure compared to the initial mix ratio.

[0035] In some embodiments of the present invention, the density failure threshold is 20-50%, the viscosity failure threshold is 100-200%, and the diamond abrasive roundness ratio failure threshold is 50%-80%. The failure threshold is determined by averaging the data of changes in density, viscosity, and diamond abrasive roundness ratio relative to the initial mix ratio of multiple sets of cutting mortars at critical failure.

[0036] In some embodiments of the present invention, the density, viscosity, and rate of change of the diamond abrasive grain roundness ratio with respect to the initial mix ratio of multiple sets of cutting mortars at critical failure are substituted into the formula. The average value is the failure threshold S. TThe failure threshold S T It can be 0.5-0.9.

[0037] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0038] Example 1 A method for rapidly determining the failure of multi-wire cutting slurry for silicon carbide ingots includes the following steps: Step 1: Take a sample of the cutting slurry from the multi-wire cutting machine at a 6-hour interval during the multi-wire cutting process for silicon carbide ingots. Step 2: Measure 20 mL using a graduated cylinder with an accuracy of ±0.1 mL, and weigh it using a balance with an accuracy of ±0.1 g to obtain 22.1 g. Substitute these values ​​into the density calculation formula: Where m is mass (in g), V is volume (in mL), and ρ is density (in g / mL), the density of the cutting mortar is 1.11 g / mL.

[0039] Step 3: Take 40 mL of cutting mortar and use a rotational viscometer to measure the viscosity of the cutting mortar at 25°C. The viscosity is 675 mPa·s. Step 4: Drip the cutting slurry onto the double copper mesh carbon film, dry it, and then observe the morphology of the diamond abrasive using a transmission electron microscope. Count the 30 diamond abrasive grains, the edge roundness number is 24, and the abrasive roundness ratio is 80%. Step 5: The density change rate of the cutting mortar is 23% < density failure threshold, the viscosity change rate is 153% > viscosity failure threshold, and the diamond abrasive grain rounding ratio is 80% > rounding ratio failure threshold. A weighted summation method is used to calculate the comprehensive failure score. W is the normalized weighting coefficient. W1 takes values ​​of 0.2-0.4, W2 takes values ​​of 0.2-0.4, and W3 takes values ​​of 0.3-0.5. I is an indicator function, taking 1 when the condition is met and 0 otherwise. I1 (density change rate ≥ density failure threshold), density failure threshold is 20-50%; I2 (viscosity change rate ≥ viscosity failure threshold), viscosity failure threshold is 100-200%; I3 (diamond abrasive grain rounding ratio ≥ rounding ratio failure threshold), diamond abrasive grain rounding ratio failure threshold is 50%-80%. S=0.7>S T The cutting mortar has been determined to be ineffective and needs to be replaced with new cutting mortar.

[0040] Example 2 A method for rapidly determining the failure of multi-wire cutting slurry for silicon carbide ingots includes the following steps: Step 1: Take samples of the cutting slurry from the observation port of the multi-wire cutting machine at 12-hour intervals before using the multi-wire cutting slurry for silicon carbide ingots. Step 2: Measure 20 mL using a graduated cylinder with an accuracy of ±0.1 mL, and weigh it using a balance with an accuracy of ±0.1 g to obtain 19.5 g. Substitute these values ​​into the density calculation formula: Where m is mass (in g), V is volume (in mL), and ρ is density (in g / mL), the density of the cutting mortar is obtained as 0.99 g / mL.

[0041] Step 3: Take 40 mL of cutting mortar and use a rotational viscometer to measure the viscosity of the cutting mortar at 25℃. The viscosity is 388 mPa·s. Step 4: Drip the cutting slurry onto the double copper mesh carbon film, dry it, and then observe the morphology of the diamond abrasive using a transmission electron microscope. Count 30 diamond abrasive grains, with 12 having blunt edges, and the blunting rate of the abrasive grains is 40%. Step 5: The density change rate of the cutting mortar is 10% < density failure threshold, the viscosity change rate is 45% > viscosity failure threshold, and the roundness ratio of the diamond abrasive grains is 40% < roundness ratio failure threshold. The weighted summation method is used to calculate the comprehensive failure score. W is the normalized weighting coefficient. W1 takes values ​​of 0.2-0.4, W2 takes values ​​of 0.2-0.4, and W3 takes values ​​of 0.3-0.5. I is an indicator function, taking 1 when the condition is met and 0 otherwise. I1 (density change rate ≥ density failure threshold), density failure threshold is 20-50%; I2 (viscosity change rate ≥ viscosity failure threshold), viscosity failure threshold is 100-200%; I3 (diamond abrasive grain roundness ratio ≥ roundness ratio failure threshold), diamond abrasive grain roundness ratio failure threshold is 50%-80%. S=0<S T The cutting mortar was determined to be in good condition and there was no need to replace it with new cutting mortar.

[0042] Example 3 A method for rapidly determining the failure of multi-wire cutting slurry for silicon carbide ingots includes the following steps: Step 1: Take samples of the cutting slurry from the observation port of the multi-wire cutting machine at 3-hour intervals after using the multi-wire cutting slurry for silicon carbide ingots. Step 2: Measure 20 mL using a graduated cylinder with an accuracy of ±0.1 mL, and weigh it using a balance with an accuracy of ±0.1 g to obtain 26 g. Substitute these values ​​into the density calculation formula: Where m is mass (in g), V is volume (in mL), and ρ is density (in g / mL), the density of the cutting mortar is 1.30 g / mL.

[0043] Step 3: Take 40 mL of cutting mortar and use a rotational viscometer to measure the viscosity of the cutting mortar at 25°C. The viscosity is 775 mPa·s. Step 4: Drip the cutting slurry onto the double copper mesh carbon film, dry it, and then observe the morphology of the diamond abrasive using a transmission electron microscope. Count 30 diamond abrasive grains, the edge roundness number is 25, and the roundness ratio of the abrasive grains is 83%. Step 5: The density change rate of the cutting mortar is 44% > density failure threshold, the viscosity change rate is 190% > viscosity failure threshold, and the roundness ratio of diamond abrasive grains is 83% > roundness ratio failure threshold. A weighted summation method is used to calculate the comprehensive failure score. W is the normalized weighting coefficient. W1 takes values ​​of 0.2-0.4, W2 takes values ​​of 0.2-0.4, and W3 takes values ​​of 0.3-0.5. I is an indicator function, taking 1 when the condition is met and 0 otherwise. I1 (density change rate ≥ density failure threshold), density failure threshold is 20-50%; I2 (viscosity change rate ≥ viscosity failure threshold), viscosity failure threshold is 100-200%; I3 (diamond abrasive grain roundness ratio ≥ roundness ratio failure threshold), diamond abrasive grain roundness ratio failure threshold is 50%-80%. S=1>S T The cutting mortar has been determined to be ineffective and needs to be replaced with new cutting mortar.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the failure of multi-wire cutting slurry for silicon carbide ingots, characterized in that, include: Obtain the density of the cutting mortar and calculate the density change rate; Obtain the viscosity of the cutting mortar and calculate the viscosity change rate; Obtain the roundness ratio of diamond abrasive; The comprehensive failure score was calculated using a weighted summation method based on the density change rate, viscosity change rate, and diamond abrasive rounding ratio. Determine whether the comprehensive failure score is greater than or equal to the failure threshold. If so, determine that the cutting mortar has failed.

2. The determination method as described in claim 1, characterized in that, The sampling frequency for cutting mortar is as follows: 12-24 h interval in the early stage of use, 6-12 h interval in the middle stage of use, and 3-6 h interval in the later stage of use.

3. The determination method as described in claim 1, characterized in that, The process of obtaining the density of the cutting mortar includes: Take 20-40 mL of cutting mortar, weigh it, and then calculate the density of the cutting mortar using the density calculation formula.

4. The determination method as described in claim 1, characterized in that, The viscosity of the cutting mortar is obtained by: Take 20-40 mL of cutting mortar and test its viscosity at 20-50℃ to obtain the viscosity of the cutting mortar.

5. The determination method as described in claim 1, characterized in that, The density change rate is the rate of change between the density of the cutting mortar to be tested and the initial density of the cutting mortar. The viscosity change rate is the rate of change between the viscosity of the cutting mortar to be tested and the initial viscosity of the cutting mortar.

6. The determination method as described in claim 1, characterized in that, The method for obtaining the roundness ratio of diamond abrasive includes: Obtain cutting slurry, dry it, observe the morphology of diamond abrasive and calculate the roundness ratio of diamond abrasive. The number of diamond abrasive morphology samples ranged from 20 to 80.

7. The determination method as described in claim 1, characterized in that, The formula for calculating the comprehensive failure score S using the weighted summation method is as follows: ; Where W is the normalized weight coefficient, W1 is the density change rate weight, W2 is the viscosity change rate weight, and W3 is the diamond abrasive grain rounding ratio weight; I is an indicator function, which takes the value 1 when the condition is met and 0 otherwise. The condition for I1 is: density change rate ≥ density failure threshold, the condition for I2 is: viscosity change rate ≥ viscosity failure threshold, and the condition for I3 is: diamond abrasive grain rounding ratio ≥ diamond abrasive grain rounding ratio failure threshold.

8. The determination method as described in claim 7, characterized in that, W1 takes values ​​of 0.2-0.4, W2 takes values ​​of 0.2-0.4, and W3 takes values ​​of 0.3-0.

5.

9. The determination method as described in claim 7, characterized in that, The failure threshold for density is 20-50%, the failure threshold for viscosity is 100-200%, and the failure threshold for the roundness ratio of diamond abrasive grains is 50%-80%.

10. The determination method as described in claim 1, characterized in that, The failure threshold is the average of the comprehensive failure scores of multiple critical failure cutting mortars.

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