A method for sapphire slicing and a sapphire slicing machine

Abstract

This application relates to the field of crystal processing technology, and in particular to a sapphire slicing method and a sapphire slicing machine. The sapphire slicing method includes: lowering a sapphire crystal rod to contact a diamond wire mesh, so that the diamond wire cuts the sapphire crystal rod; acquiring processing parameters during the cutting process; determining a diamond wire life index based on the processing parameters; and replacing the diamond wire when the diamond wire life index falls below a preset threshold. This method can dynamically update the diamond wire wear assessment results in real time following changes in processing conditions, achieving the technical effect of accurately judging the diamond wire life.

Description

Technical Field

[0001] This application relates to the field of crystal processing technology, and in particular to a sapphire slicing method and a sapphire slicing machine. Background Technology

[0002] Currently, the most common finishing process for sapphire crystals is diamond wire multi-wire slicing. This process relies on a main roller carrying a diamond wire mesh to cut the crystal ingot. With its advantages of low kerf loss, high slicing precision, and excellent surface quality, it has become the core processing method for the mass production of sapphire substrates and optical wafers. However, sapphire has a Mohs hardness of 9, is highly brittle, and exhibits significant anisotropy. During the cutting process, the diamond wire must continuously withstand high-frequency friction and impact loads, making it highly susceptible to wear problems such as diamond abrasive grain shedding, abrasive grain height reduction, and coating fatigue damage.

[0003] In existing technologies, it is impossible to quantify the wear state and remaining cutting life of diamond wire online. There is no real-time physical quantity coupling calculation method. It can only rely on experience to predict based on fixed cutting length and processing time, which has extremely poor accuracy. The industry-standard detection method is to stop the machine and take samples, and observe the morphology and wear degree of abrasive particles offline through a microscope. This method not only cannot adapt to the dynamic changes in processing, but also interrupts production, reduces processing efficiency, and makes it difficult to predict the hidden fatigue damage of the saw wire, which can easily lead to quality and safety problems such as wire breakage, wafer edge breakage, and excessive thickness deviation.

[0004] Therefore, the technical problem with existing technology is that it is difficult to determine the lifespan of diamond wire. Summary of the Invention

[0005] This application provides a sapphire slicing method and a sapphire slicing machine, which achieves the technical effect of accurately judging the life of diamond wire by processing and calculating the processing parameters.

[0006] On the one hand, the sapphire slicing method provided in this application adopts the following technical solution: A method for sapphire slicing includes: The sapphire crystal rod is lowered to contact the diamond wire mesh, so that the diamond wire cuts the sapphire crystal rod. Obtain the processing parameters during the cutting process, and determine the diamond wire life index based on the processing parameters; Replace the diamond wire when its lifespan index falls below a preset threshold.

[0007] Preferably, the step of obtaining processing parameters during the cutting process and determining the diamond wire life index based on the processing parameters includes: Based on the machining parameters, determine the effective amplitude of the cutting interface; Based on the effective amplitude, determine the diamond wire parameters; Based on the diamond wire parameters, the material removal rate is determined; Based on the material removal rate, the cumulative volume of sapphire removed is determined; The remaining effective cutting length is determined based on the total volume, the cumulative volume of sapphire cut off, the cutting cross-sectional area, and the wafer thickness.

[0008] Preferably, the processing parameters include cutting acceleration, diamond wire tension, slurry noise spectrum, and diamond wire reversal impact frequency. Determining the effective amplitude of the cutting interface based on the machining parameters includes: Based on the cutting acceleration, the global vibration spectrum is obtained through Fourier transform; The mortar noise power is obtained by integrating the mortar noise spectrum, and the total vibration power is obtained by integrating the global vibration spectrum. The mortar noise power ratio is determined based on the ratio of the mortar noise power to the total vibration power. Based on the mortar noise power ratio, the original spectrum of crystal rod cutting and the corresponding main peak amplitude are obtained by eliminating mortar fluid interference. The effective amplitude of the cutting interface is determined based on the main peak amplitude of the original spectrum of the crystal rod cutting, the commutation impact frequency of the diamond wire, and the commutation impact attenuation coefficient.

[0009] Preferably, the global vibration spectrum is The mortar noise spectrum is ; The mortar noise power was determined by integrating across the entire frequency band. Total vibration power :

[0010]

[0011] Mortar noise power ratio:

[0012] The original spectrum of the crystal rod cutting was obtained after removing fluid interference:

[0013] The amplitude corresponding to the main peak frequency of the original spectrum of the crystal rod cutting is extracted as follows: Based on diamond wire commutation impact frequency Commutation impact attenuation coefficient Calculate the effective amplitude: .

[0014] Preferably, the diamond wire parameters include the average protrusion height of the abrasive grains, the density of the abrasive grain shedding surface, and the amount of fatigue damage to the coating. The determination of diamond wire parameters based on the effective amplitude includes: Based on the effective amplitude and the diamond wire tension fluctuation amplitude, the average protrusion height of the abrasive grains is determined; The density of the abrasive shedding surface is determined based on the average protrusion height and effective amplitude attenuation rate of the abrasive particles. The fatigue damage of the coating is determined based on the time-domain integral result of the abrasive particle shedding surface density and the amplitude of diamond wire tension fluctuation.

[0015] As a preferred method, the amplitude of the diamond wire tension fluctuation is determined based on the maximum and minimum tension of the diamond wire. :

[0016] By setting the abrasive height calibration coefficient Determine the average protrusion height of abrasive grains :

[0017] The amplitude decay rate is obtained by differentiating the effective amplitude in the time domain. Based on the preset abrasive grain shedding attenuation calibration coefficient Determine the surface density of abrasive grains. for:

[0018] The abrasive grain shedding surface density is integrally analyzed over the entire time domain, based on a preset coating fatigue damage accumulation coefficient. Diamond wire tension fluctuation amplitude Determine the amount of fatigue damage in the coating. : .

[0019] Preferably, the determination of the material removal rate based on the diamond wire parameters; the determination of the cumulative sapphire volume removed based on the material removal rate; and the determination of the remaining effective cutting length based on the total volume, the cumulative sapphire volume removed, the cutting cross-sectional area, and the wafer thickness include: Material removal rate for:

[0020] in, The cutting efficiency constant corresponding to the sapphire crystal plane; Total volume of sapphire cut for:

[0021] in, This is the current processing time; It is an integral dummy variable; Remaining effective cutting length for:

[0022] in, To remove the total volume to the limit; This represents the cross-sectional area of ​​a single filament being cut. This refers to the wafer thickness.

[0023] As a preferred option, it also includes: A functional relationship model for diamond wire life index is established with the average protrusion height of the abrasive grains, the surface density of the abrasive grains, the fatigue damage of the coating, and the remaining effective cutting length as inputs. Based on the obtained average abrasive protrusion height, abrasive shedding surface density, coating fatigue damage, remaining effective cutting length, and the aforementioned functional relationship model, the diamond wire life index is determined. The diamond wire life index :

[0024] in, This represents the theoretical maximum cutting length of diamond wire. This represents the remaining effective cutting length of the diamond wire.

[0025] As a preferred option, it also includes: Beforehand, multiple sets of sapphire slice calibration tests were conducted to obtain the critical value of the lifetime index under conditions of no wire breakage and no edge chipping, which was then used as a preset threshold. ; Compare the diamond wire life index and preset threshold ; when When the diamond wire reaches its lifespan limit, a diamond wire replacement prompt and a shutdown warning will be issued.

[0026] On the other hand, the sapphire slicing machine provided in this application adopts the following technical solution: A sapphire slicing machine for performing the sapphire slicing method described above.

[0027] In summary, this application includes at least one of the following beneficial technical effects: This application realizes a closed loop between the basic processing flow and online life assessment, early warning and replacement, which solves the problem of large error in predicting life by relying on fixed time and fixed cutting length. It can dynamically follow the changes in processing conditions and update the diamond wire wear assessment results in real time, thus achieving the technical effect of accurately judging the life of diamond wire. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the sapphire slicing method described in this application; Figure 2 This is a flowchart illustrating an embodiment of the sapphire slicing method described in this application; Figure 3 This is a flowchart illustrating another embodiment of the sapphire slicing method described in this application; Figure 4 This is a flowchart illustrating another embodiment of the sapphire slicing method described in this application. Detailed Implementation

[0029] The serial numbers assigned to components in this document, such as "first" and "second," are used solely to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used solely for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0030] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0031] To better understand the above technical solutions, a detailed description of the technical solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the scope of this application.

[0032] Sapphire crystals are characterized by high hardness, brittleness, and significant anisotropy. Currently, the industry commonly uses a main roller to carry diamond wire to form a wire mesh, which is combined with the ingot feeding and descent to complete the sapphire ingot slicing process. This processing method has low kerf loss and high wafer flatness, and is widely used in the mass production processing of sapphire optical substrates and LED substrate wafers.

[0033] During sapphire cutting, diamond wire is continuously subjected to high-frequency friction and crystal impact loads. The diamond abrasive grains gradually detach, and the abrasive grain protrusion height continuously decreases. At the same time, the diamond wire coating suffers fatigue damage. Multiple losses significantly shorten the service life of the diamond wire. Current technology cannot quantify the wear state and remaining cutting life of the diamond wire in real time online. It relies solely on experience to predict the wear state and remaining cutting life based on fixed cutting lengths and fixed processing times, resulting in poor prediction accuracy. The industry standard testing method requires stopping the machine, removing diamond wire samples, and observing the abrasive grain morphology and coating loss offline under a microscope. This process interrupts production and reduces processing efficiency. Furthermore, offline testing cannot capture the hidden fatigue damage to the coating generated by the diamond wire during processing. This makes it very easy for the diamond wire to break during processing, causing problems such as crystal rod scratches, wafer edge breakage, and wafer thickness TTV exceeding tolerances, resulting in production scrap.

[0034] This application aims to overcome the shortcomings of existing technologies, such as the inability to quantitatively assess diamond wire wear online, the limitation to offline detection, low accuracy in lifespan prediction, and the susceptibility to wire breakage and scrapping. It provides a sapphire slicing method and a sapphire slicing machine. By collecting multiple types of real-time processing sensor parameters and performing multi-layer coupling calculations, the physical quantities characterizing diamond wire wear and the remaining effective cutting length are obtained. Furthermore, a comprehensive lifespan risk index is constructed as a diamond wire lifespan indicator, enabling online dynamic assessment of diamond wire lifespan throughout the entire processing process. This eliminates the need for offline detection without machine downtime, provides early warning of wire breakage risks, and improves wafer processing yield and production efficiency.

[0035] This application proposes a method for sapphire slicing, such as... Figure 1 As shown, it includes: S1: Lower the sapphire crystal rod to contact the diamond wire mesh so that the diamond wire can cut the sapphire crystal rod; S2: Obtain the processing parameters during the cutting process, and determine the diamond wire life index based on the processing parameters; S3: Replace the diamond wire when the diamond wire life index is lower than the preset threshold.

[0036] Specifically, the first step is to control the descent of the sapphire crystal rod so that it comes into contact with the diamond wire mesh carried on the main roller of the equipment. Under continuous feeding, the high-speed diamond wire completes the cutting and slicing operation of the sapphire crystal rod. During the processing, the diamond wire and the sapphire crystal rod continuously rub and impact each other, and simultaneously generate physical signals such as cutting vibration, tension fluctuation, and slurry fluid noise. The second step involves continuously collecting various real-time processing parameters throughout the slicing process. All collected processing parameters are then input into the equipment control system. Through multi-layer mathematical coupling calculations, a diamond wire life index that comprehensively reflects diamond wire wear and breakage risk is obtained. The simple judgment method of directly comparing a single parameter with a threshold is abandoned, and the wear state is quantitatively characterized by multi-parameter simultaneous calculations. The third step is to compare the real-time calculated diamond wire life index with the pre-calibrated preset threshold. When the diamond wire life index is lower than the preset threshold, it is determined that the diamond wire is severely worn and there is a risk of wire breakage. The system outputs a prompt signal, and the operator replaces the diamond wire before proceeding with subsequent slicing processing.

[0037] Among these steps, obtaining the processing parameters during the cutting process and determining the diamond wire life index based on these parameters includes: S21: Determine the effective amplitude of the cutting interface based on machining parameters; S22: Determine the diamond wire parameters based on the effective amplitude; S23: Determine the material removal rate based on diamond wire parameters; S24: Determine the cumulative volume of sapphire removed based on the material removal rate; S25: Determine the remaining effective cutting length based on the total volume, the cumulative volume of sapphire cut off, the cutting cross-sectional area, and the wafer thickness.

[0038] Understandably, the process of acquiring processing parameters and determining the diamond wire life index based on those parameters is defined by a five-layer subdivision calculation flow. These five layers of calculation proceed sequentially, with the output of the previous layer serving as the input for the next, thus fully realizing the solution from the original sensor parameters to the remaining effective cutting length. Specifically: The first layer of calculation process: Based on all processing parameters collected by the equipment in real time, the effective amplitude of the cutting interface is obtained through spectrum noise reduction and impact interference compensation calculation. The effective amplitude is the vibration characteristic quantity that reflects only the cutting action of diamond wire abrasive after eliminating the interference of slurry fluid and crystal fragmentation. It is the basic input quantity for subsequent diamond wire wear parameter calculation. The second layer of calculation process: The effective amplitude of the cutting interface obtained in the previous step is used as input, and the tension fluctuation data is combined to solve three types of diamond wire parameters that cannot be directly observed online. The three types of diamond wire parameters respectively characterize the wear morphology of abrasive particles, the degree of abrasive particle shedding, and the fatigue damage inside the coating. The third layer of calculation process: the parameters of the three types of diamond wire are coupled and calculated to solve the instantaneous material removal rate; the instantaneous material removal rate represents the material removal capability of the diamond wire in cutting sapphire at the current moment, and it will continuously change dynamically with abrasive wear and coating damage; The fourth layer of calculation process: Perform time-domain integration on the real-time updated instantaneous material removal rate, and sum them up to obtain the total volume of sapphire that the diamond wire has cut off from the start of the slicing process to the current moment; The fifth layer of the calculation process: three sets of fixed calibration constants are pre-stored: the ultimate total volume of diamond wire, the cutting cross-sectional area of ​​a single diamond wire, and the thickness of the target finished wafer. Combined with the cumulative volume of sapphire cut off obtained from the integration in the previous step, the remaining effective cutting length of the diamond wire is calculated using the volume conversion formula. The remaining effective cutting length represents the theoretically still stable cutting length of sapphire by the diamond wire, and is used to characterize the degree of cutting capacity loss of the diamond wire material.

[0039] In this way, a multi-level progressive calculation link is built to realize the transformation of externally collectable sensor parameters into internal wear physical quantities and remaining processing capacity. Each step of the calculation involves parameter coupling, and there is no logic for direct determination of a single parameter, which improves the accuracy of life assessment.

[0040] Furthermore, the processing parameters include cutting acceleration, diamond wire tension, slurry noise spectrum, and diamond wire reversing impact frequency. Specifically, there are four types of processing parameters used for calculation, all of which are acquired online in real time by sensors: The first type is cutting acceleration, which is acquired by a high-frequency acceleration sensor arranged on the rigid outer wall of the main roller bearing housing. The vibration of the cutting interface is transmitted to the main roller and the bearing housing. The acceleration signal acquired by the sensor on the bearing housing can directly characterize the cutting acceleration of the cutting interface. The second type is diamond wire tension, which is acquired in real time by a tension sensor built into the tension wheel to collect continuous tension data. The third type is slurry noise spectrum, which is acquired by an acoustic sensor next to the slurry cooling pipe to collect the fluid vibration spectrum. The fourth type is diamond wire reversing impact frequency, which is calculated from the speed signal of the main roller encoder. The parameters are independent of each other and respectively characterize four different physical states: cutting impact, saw wire load, fluid interference, and reciprocating reversing impact.

[0041] like Figure 3 As shown, based on machining parameters, the effective amplitude of the cutting interface is determined as follows: S211: Based on cutting acceleration, the global vibration spectrum is obtained through Fourier transform; S212: Mortar noise power is obtained based on the integral of the mortar noise spectrum, and total vibration power is obtained based on the integral of the global vibration spectrum. S213: Determine the mortar noise power ratio based on the ratio of mortar noise power to total vibration power; S214: Based on the mortar noise power ratio, the original spectrum of crystal rod cutting and the corresponding main peak amplitude are obtained by eliminating mortar fluid interference; S215: Determine the effective amplitude of the cutting interface based on the main peak amplitude of the original spectrum of crystal rod cutting, the diamond wire commutation impact frequency, and the commutation impact attenuation coefficient.

[0042] Specifically, the first step is to perform a Fourier transform on the acquired cutting acceleration time-domain signal to obtain the global vibration spectrum. The global vibration spectrum fully includes the full-frequency vibration energy corresponding to all vibration sources such as cutting, fluid, commutation impact, and crystal fragmentation, without pre-filtering any frequency range. The second step is to perform a full-band integral calculation on the mortar noise spectrum, and the integral result is defined as the mortar noise power; simultaneously, a full-band integral calculation is performed on the global vibration spectrum, and the integral result is defined as the total vibration power; the mortar noise power represents the total vibration energy generated by the impact of mortar fluid and pipe abrasive debris, and the total vibration power represents the total vibration energy after the superposition of all vibration sources at the processing site. The third step is to calculate the ratio of mortar noise power to total vibration power to obtain the mortar noise power ratio. This ratio represents the proportion of fluid noise in the total vibration energy of the whole machine and is used to quantitatively eliminate fluid interference components. The fourth step is to use the mortar noise power ratio to correct the global vibration spectrum, remove the vibration interference component brought by the mortar fluid, and obtain the original spectrum of the crystal rod cutting that only contains the vibration related to crystal cutting. At the same time, the amplitude of the main peak corresponding to the main peak frequency of the spectrum is extracted. The fifth step involves combining the main peak amplitude of the original spectrum of the crystal rod cutting, the real-time acquired diamond wire reversal impact frequency, and the reversal impact attenuation coefficient pre-calibrated by the equipment to eliminate the vibration interference caused by the instantaneous impact of sapphire brittle fracture, and finally calculate the effective amplitude of the cutting interface.

[0043] Thus, through multi-layer calculations of spectrum integration, proportional correction, and impact attenuation compensation, two types of irrelevant vibration interference are separated, vibration characteristic quantities related only to abrasive cutting are purified, and calculation errors caused by slurry flow rate, abrasive concentration, and crystal fragmentation are eliminated.

[0044] Furthermore, the global vibration spectrum is The mortar noise spectrum is obtained from the Fourier transform of the cutting acceleration time-domain signal. The data was collected by acoustic sensors in the mortar pipeline. This represents the minimum upper frequency limit of the acquired spectrum; This represents the lowest frequency limit of the acquired spectrum; The mortar noise power was determined by integrating across the entire frequency band. :

[0045] The mortar noise spectrum was integrated over the entire frequency band from the lowest to the highest frequency. The integration result was obtained. This represents the noise power of the mortar; it is used to quantitatively calculate all the vibration energy generated by the impact of mortar fluid and pipe abrasive debris, and is used for subsequent calculations of the proportion of fluid interference.

[0046] The total vibration power is determined by integrating across the entire frequency band. :

[0047] Within the same complete frequency band, perform an integral operation on the global vibration spectrum, and obtain the integral result. It represents the total vibration power; used to statistically analyze the total vibration energy generated by the superposition of all vibration sources at the slicing processing site, serving as a benchmark for fluid interference correction.

[0048] Mortar noise power ratio:

[0049] in, This represents the proportion of mortar noise power and is also a correction factor for fluid interference. The mortar noise power is divided by the total vibration power to obtain the energy proportion of fluid noise in the overall vibration, which is used to quantify the degree of fluid interference and provide a quantitative correction factor for eliminating mortar-related vibrations.

[0050] The original spectrum of the crystal rod cutting was obtained after removing fluid interference:

[0051] in, This represents the original spectrum of crystal rod cutting after removing fluid interference; the difference between multiplying the original global vibration spectrum by 1 and subtracting the fluid interference correction coefficient is used to strip the vibration energy component corresponding to the mortar fluid; this is used to eliminate the artificially high vibration amplitude caused by fluctuations in mortar flow rate and abrasive dust concentration, while retaining the vibration spectrum related to crystal cutting.

[0052] The amplitude corresponding to the main peak frequency of the original spectrum extracted from the crystal rod cutting is Based on diamond wire commutation impact frequency Commutation impact attenuation coefficient Calculate the effective amplitude : .

[0053] The amplitude of the cutting peak is combined with the reversing impact frequency and the attenuation coefficient to perform an exponential decay calculation to counteract the interference of the instantaneous pulse vibration of the brittle fracture of the sapphire crystal; the vibration amplitude that is only reflected by the scratching and cutting action of the diamond abrasive grains is used in the final purification process as the basic input for the calculation of diamond wire wear parameters.

[0054] Furthermore, diamond wire parameters include the average abrasive protrusion height, abrasive shedding surface density, and coating fatigue damage. These three types of diamond wire parameters are implicit physical quantities that cannot be directly measured online by sensors and can only be calculated by combining sensor parameters: the first type is the average abrasive protrusion height, which characterizes the height of diamond particles exposed on the diamond wire surface and directly determines the cutting removal capacity; the second type is the abrasive shedding surface density, which characterizes the proportion of the diamond wire per unit area where diamond abrasive particles have detached or are missing; and the third type is the coating fatigue damage, which characterizes the degree of internal fatigue damage caused by the long-term accumulation of alternating loads on the diamond wire coating.

[0055] like Figure 4 As shown, based on the effective amplitude, the parameters of the diamond wire are determined as follows: S221: Determine the average protrusion height of abrasive grains based on the effective amplitude and the amplitude of diamond wire tension fluctuation; S222: Determine the density of abrasive shedding surface based on the average protrusion height of abrasive particles and the effective amplitude attenuation rate; S223: Determine the amount of fatigue damage to the coating based on the time-domain integral results of the abrasive particle shedding surface density and the amplitude of diamond wire tension fluctuation.

[0056] Specifically, the first step is to combine the effective amplitude of the cutting interface and the real-time calculated amplitude of the diamond wire tension fluctuation to solve for the average protrusion height of the abrasive grains. The amplitude of the tension fluctuation reflects the magnitude of the saw wire load fluctuation during the cutting process. The load directly affects the vibration amplitude. Combining the two eliminates load interference and obtains the true protrusion height of the abrasive grains. The second step is to use the average protrusion height of the abrasive grains and the time-domain decay rate of the effective amplitude obtained in the first step as inputs to solve for the abrasive grain shedding surface density. The continuous decay of the effective amplitude indicates that the diamond abrasive grains are constantly falling off. Combined with the abrasive grain height, the severity of the shedding can be quantitatively calculated. The third step is to perform time-domain integration on the abrasive grain shedding surface density at every instant during the entire processing to obtain the total cumulative abrasive grain shedding. Then, by combining the amplitude of the diamond wire tension fluctuation, the fatigue damage of the coating is solved. The tension fluctuation brings cyclic alternating stress, and the cumulative abrasive grain shedding causes stress concentration in the coating. The superposition of the two determines the degree of cumulative fatigue damage of the coating.

[0057] In this way, externally measurable vibration and tension parameters can be converted into implicit physical quantities such as wear morphology and coating damage inside the saw wire, and the wear state of diamond wire can be quantified online without offline microscope observation.

[0058] More specifically, the amplitude of tension fluctuation in the diamond wire is determined based on the maximum and minimum tension of the diamond wire. :

[0059] This represents the amplitude of the tension fluctuation in the diamond wire. This represents the maximum tension of the diamond wire within a single sampling period. The minimum tension of the diamond wire within a single sampling period is given; the maximum tension minus the minimum tension within the same sampling period yields the tension fluctuation difference; this is used to quantify the amplitude of the alternating load fluctuation borne by the diamond wire during the cutting process and is a necessary input for calculating abrasive height and coating damage.

[0060] By setting the abrasive height calibration coefficient Determine the average protrusion height of abrasive grains :

[0061] This represents the average protrusion height of the abrasive grains. The abrasive height calibration coefficient is a fixed constant obtained by fitting a standard diamond wire calibration test before the equipment leaves the factory. The effective amplitude of the cutting interface; The effective amplitude is the amplitude of the tension fluctuation of the diamond wire. The square root of the effective amplitude and the amplitude of the tension fluctuation are divided and then multiplied by the abrasive height calibration coefficient to obtain the average exposed height of the diamond abrasive. This can eliminate the interference of cutting load fluctuation on the vibration amplitude and quantitatively invert the abrasive morphology characteristics from the purified vibration signal.

[0062] The amplitude decay rate is obtained by differentiating the effective amplitude in the time domain. Based on the preset abrasive grain shedding attenuation calibration coefficient Determine the surface density of abrasive grains. for:

[0063] The surface density of abrasive grains. The abrasive shedding attenuation calibration coefficient is a fixed constant calibrated at the factory. This represents the average protrusion height of the abrasive grains. The effective amplitude is the time-domain differential, representing the rate of decay of the effective amplitude over time. The effective amplitude decay rate is calculated in conjunction with the abrasive height and the shedding calibration coefficient. The negative sign indicates that the amplitude continues to decrease as the abrasive particles shed. The instantaneous abrasive shedding surface density is calculated. This can quantitatively characterize the severity of diamond particle shedding on the diamond wire surface at any given time.

[0064] The abrasive grain shedding surface density is integrally analyzed over the entire time domain, based on a preset coating fatigue damage accumulation coefficient. Diamond wire tension fluctuation amplitude Determine the amount of fatigue damage in the coating. : .

[0065] This represents the amount of fatigue damage to the coating. This is the cumulative fatigue damage coefficient of the coating, a fixed constant calibrated at the factory. For the current moment of slice processing; It is an integral dummy variable, representing any instantaneous processing time within the interval from 0 to the current time. For any instant The corresponding abrasive grain shedding surface density; from the start of processing at time 0 to the current time, the abrasive grain shedding surface density at each instant is integrated to obtain the cumulative abrasive grain shedding amount, which is then multiplied by the tension fluctuation amplitude and the coating damage accumulation coefficient to obtain the cumulative coating fatigue damage amount throughout the process; this is used to quantify the internal fatigue damage caused by the long-term alternating stress and concentrated abrasive grain shedding stress of the diamond wire coating, and to predict the risk of the line.

[0066] Furthermore, based on the diamond wire parameters, the material removal rate is determined; based on the material removal rate, the cumulative volume of sapphire removed is determined; based on the total volume, the cumulative volume of sapphire removed, the cutting cross-sectional area, and the wafer thickness, the remaining effective cutting length is determined; in other words, the instantaneous material removal rate is calculated based on the average abrasive grain protrusion height, abrasive grain shedding surface density, and coating fatigue damage; the instantaneous material removal rate is integrated in the time domain to obtain the cumulative volume of sapphire removed; based on the preset saw wire limit removal total volume, the cumulative volume of sapphire removed, the preset single-wire cutting cross-sectional area, and the preset wafer thickness, the remaining effective cutting length is calculated. The preset single-wire cutting cross-sectional area is the equivalent cross-sectional area of ​​a single diamond wire participating in the cutting, calibrated by the diamond wire baseline diameter and the diamond abrasive grain protrusion amount, and is pre-stored in the control system before slicing processing to convert the remaining machinable sapphire volume into the remaining effective cutting length of the diamond wire.

[0067] Specifically, material removal rate for:

[0068] in, The cutting efficiency constant corresponding to the sapphire crystal plane; Total volume of sapphire cut for:

[0069] in, This is the current processing time; It is an integral dummy variable; Remaining effective cutting length for:

[0070] in, To remove the total volume to the limit; This represents the cross-sectional area of ​​a single filament being cut. This refers to the wafer thickness.

[0071] Furthermore, it also includes: A functional relationship model for diamond wire life index was established with the average protrusion height of abrasive grains, the density of abrasive grain shedding surface, the amount of fatigue damage of coating, and the remaining effective cutting length as inputs. Based on the obtained average abrasive protrusion height, abrasive shedding surface density, coating fatigue damage, remaining effective cutting length, and functional relationship model, the diamond wire life index is determined.

[0072] After obtaining four types of characteristic quantities—average abrasive protrusion height, abrasive detachment surface density, coating fatigue damage, and remaining effective cutting length—the solution also includes: A multi-input functional relationship model was constructed. The input variables of the model include the average protrusion height of abrasive grains, the density of abrasive grain detachment surface, the amount of fatigue damage to the coating, and the remaining effective cutting length. The output variable of the model is the diamond wire life index. This model integrates three independent failure dimensions: abrasive cutting failure, coating fatigue damage, and material cutting capacity loss, and no longer relies solely on the remaining cutting length to determine the life.

[0073] The four types of characteristic quantities, which are calculated and updated in real time, are all substituted into a pre-established functional relationship model. The diamond wire life index is obtained in real time through model coupling calculation. The diamond wire life index is a unified quantitative value. The value reflects the degree of diamond wire cutting ability decay, coating breakage risk, and remaining machinable capacity. It serves as a unified basis for equipment early warning and diamond wire replacement.

[0074] Further optimization addresses the shortcomings of relying solely on the remaining effective cutting length to predict lifespan. It can identify high-risk conditions where the remaining cutting length is sufficient but abrasive grains have detached over a large area and the coating has been severely damaged, thus preventing premature line breakage and scrapping.

[0075] More specifically, diamond wire life indicators :

[0076] in, This is an indicator of the lifespan of diamond wire, also known as the comprehensive wear risk index. The surface density of abrasive grains. The average protrusion height of the abrasive grains. This represents the amount of fatigue damage to the coating. This represents the theoretical maximum cutting length of diamond wire. This represents the remaining effective cutting length of the diamond wire.

[0077] Diamond wire life index In the model, This value represents the degree of abrasive cutting failure. The higher the density of the abrasive shedding surface and the lower the abrasive protrusion height, the more this value increases, indicating a significant reduction in diamond wire cutting capability. This represents the fatigue damage weight of the coating; the higher the coating damage value, the greater the risk of wire breakage. This represents the proportion of the diamond wire that has been used and worn out relative to the total maximum length. The closer the cut length is to the maximum length, the larger this value will be.

[0078] By multiplying and coupling three dimensions—abrasive cutting failure, coating fatigue damage, and saw wire wear—a unified comprehensive risk value is obtained. Exacerbation of any one of these negative wear characteristics will simultaneously increase the risk level. Even if the remaining effective cutting length If the value is large, and there is severe abrasive grain shedding or a large accumulation of coating damage, the overall... The risk will still increase significantly. Therefore, constructing a unified quantitative risk index that simultaneously considers both the material cutting capacity and the structural strength failure risk of the saw wire body can solve the problem of missing judgment lines based solely on the remaining cutting length.

[0079] Furthermore, it also includes: obtaining the critical value of the lifetime index under conditions of no wire breakage and no edge chipping through multiple sets of sapphire slice calibration tests in advance as a preset threshold. ; Comparison of diamond wire life indicators and preset threshold ; when When the diamond wire reaches its lifespan limit, a diamond wire replacement prompt and a shutdown warning will be issued.

[0080] First, multiple sets of sapphire slice calibration tests were completed in advance, collecting a large amount of slice data showing no wire breaks, no wafer chipping, and stable processing conditions. The diamond wire life index values ​​corresponding to each set of tests were statistically analyzed, and a safety critical value was selected as the preset threshold. The data is stored in the slicing machine control system. Preset thresholds distinguish between diamond wires of different specifications and sapphire crystal faces, adapting to different processing scenarios; Next, during the slicing process, the control system continuously calculates the diamond wire life index in real time. Continuously provide real-time updates With preset threshold Perform numerical comparison; Finally, the numerical comparison logic determines that when the diamond wire life index calculated in real time is greater than or equal to the preset threshold, the system determines that the current diamond wire wear has reached its limit and there is an extremely high risk of wire breakage. The equipment simultaneously outputs a text prompt for diamond wire replacement and an audible and visual shutdown warning signal. After receiving the prompt, the operator stops the machine to replace the diamond wire, avoiding the scrapping of crystal rods and wafers caused by wire breakage during processing.

[0081] Thus, this application relies on a comprehensive risk index calculated by coupling multiple physical quantities as a judgment benchmark, which differs from the simple comparison and judgment based on fixed processing time and fixed tension threshold in existing technologies, resulting in higher prediction accuracy.

[0082] This application also proposes a sapphire slicing machine, which is equipped with a controller and multiple sets of sensor acquisition modules. The controller has a built-in program that can execute the above-mentioned sapphire slicing method. The hardware components of the equipment include, but are not limited to, a main roller assembly that carries diamond wire mesh, a feed table that loads sapphire crystal rods, a tension wheel tension sensor, a high-frequency acceleration sensor for the main roller bearing seat, an acoustic sensor for the slurry pipeline, a main roller encoder, an audible and visual early warning module, and a control system that stores calibration constants.

[0083] During equipment operation, various sensors synchronously collect processing parameters and transmit them to the control system. The controller calculates the effective amplitude of the cutting interface, the three types of wear parameters of the diamond wire, the material removal rate, the cumulative cutting volume, the remaining effective cutting length, and the comprehensive life risk index in real time according to the aforementioned multi-layer coupled calculation logic. It automatically compares the threshold and outputs early warning prompts. The entire process does not require manual offline detection of the diamond wire wear status, realizing automated online diamond wire life assessment.

[0084] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0085] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for sapphire slicing, characterized in that, include: The sapphire crystal rod is lowered to contact the diamond wire mesh, so that the diamond wire cuts the sapphire crystal rod. Obtain the processing parameters during the cutting process, and determine the diamond wire life index based on the processing parameters; Replace the diamond wire when its lifespan index falls below a preset threshold.

2. The sapphire slicing method according to claim 1, characterized in that, The process of acquiring processing parameters during the cutting process and determining the diamond wire life index based on the processing parameters includes: Based on the machining parameters, determine the effective amplitude of the cutting interface; Based on the effective amplitude, determine the diamond wire parameters; Based on the diamond wire parameters, the material removal rate is determined; Based on the material removal rate, the cumulative volume of sapphire removed is determined; The remaining effective cutting length is determined based on the total volume, the cumulative volume of sapphire cut off, the cutting cross-sectional area, and the wafer thickness.

3. The sapphire slicing method according to claim 2, characterized in that, The processing parameters include cutting acceleration, diamond wire tension, slurry noise spectrum, and diamond wire reversal impact frequency. Determining the effective amplitude of the cutting interface based on the machining parameters includes: Based on the cutting acceleration, the global vibration spectrum is obtained through Fourier transform; The mortar noise power is obtained by integrating the mortar noise spectrum, and the total vibration power is obtained by integrating the global vibration spectrum. The mortar noise power ratio is determined based on the ratio of the mortar noise power to the total vibration power. Based on the mortar noise power ratio, the original spectrum of crystal rod cutting and the corresponding main peak amplitude are obtained by eliminating mortar fluid interference. The effective amplitude of the cutting interface is determined based on the main peak amplitude of the original spectrum of the crystal rod cutting, the commutation impact frequency of the diamond wire, and the commutation impact attenuation coefficient.

4. The sapphire slicing method according to claim 3, characterized in that, The global vibration spectrum is The mortar noise spectrum is ; The mortar noise power was determined by integrating across the entire frequency band. Total vibration power ; Mortar noise power ratio: The original spectrum of crystal rod cutting was obtained after eliminating fluid interference based on the mortar noise power ratio. The amplitude corresponding to the main peak frequency of the original spectrum of the crystal rod cutting is extracted as follows: Based on diamond wire commutation impact frequency Commutation impact attenuation coefficient Calculate the effective amplitude .

5. A sapphire slicing method according to claim 2, characterized in that, The diamond wire parameters include the average protrusion height of abrasive grains, the density of abrasive grain shedding surface, and the amount of fatigue damage to the coating. The determination of diamond wire parameters based on the effective amplitude includes: Based on the effective amplitude and the diamond wire tension fluctuation amplitude, the average protrusion height of the abrasive grains is determined; The density of the abrasive shedding surface is determined based on the average protrusion height and effective amplitude attenuation rate of the abrasive particles. The fatigue damage of the coating is determined based on the time-domain integral result of the abrasive particle shedding surface density and the amplitude of diamond wire tension fluctuation.

6. The sapphire slicing method according to claim 5, characterized in that, Determine the amplitude of diamond wire tension fluctuation based on the maximum and minimum tension of the diamond wire. ; By setting the abrasive height calibration coefficient Determine the average protrusion height of abrasive grains ; The amplitude decay rate is obtained by differentiating the effective amplitude in the time domain. Based on the preset abrasive grain shedding attenuation calibration coefficient Determine the surface density of abrasive grains. ; The abrasive grain shedding surface density is integrally analyzed over the entire time domain, based on a preset coating fatigue damage accumulation coefficient. Diamond wire tension fluctuation amplitude Determine the amount of fatigue damage in the coating. .

7. A sapphire slicing method according to claim 5, characterized in that, The material removal rate is determined based on the diamond wire parameters; Based on the material removal rate, the cumulative volume of sapphire removed is determined; Based on the total volume, the cumulative volume of sapphire removed, the cutting cross-sectional area, and the wafer thickness, the remaining effective cutting length is determined as follows: Material removal rate for: in, The cutting efficiency constant corresponding to the sapphire crystal plane; Total volume of sapphire cut for: in, This is the current processing time; It is an integral dummy variable; Remaining effective cutting length for: in, To remove the total volume to the limit; This represents the cross-sectional area of ​​a single filament being cut. This refers to the wafer thickness.

8. A sapphire slicing method according to claim 7, characterized in that, Also includes: A functional relationship model for diamond wire life index is established with the average protrusion height of the abrasive grains, the surface density of the abrasive grains, the fatigue damage of the coating, and the remaining effective cutting length as inputs. Based on the obtained average abrasive protrusion height, abrasive detachment density, coating fatigue damage, remaining effective cutting length, and the aforementioned functional relationship model, the diamond wire life index is determined. .

9. A sapphire slicing method according to claim 7 or 8, characterized in that, Also includes: Beforehand, multiple sets of sapphire slice calibration tests were conducted to obtain the critical value of the lifetime index under conditions of no wire breakage and no edge chipping, which was then used as a preset threshold. ; Compare the diamond wire life index and preset threshold ; when When the diamond wire reaches its lifespan limit, a diamond wire replacement prompt and a shutdown warning will be issued.

10. A sapphire slicing machine, characterized in that, Perform the sapphire slicing method as described in any one of claims 1-9.

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