Research On The Temperature And Thermal Deformation Of The Hard-brittle Monocrystal Materials With Fixed Abrasive Diamond Wire

Hard-brittle single crystal materials such as sapphire and silicon carbide are widely used in modern optoelectronic information industry.During the manufacturing of wafer,slicing is the first step and plays a decisive role in the subsequently processing.At present,the use of diamond wire saw multi-wire cutting has become the main processing method for such materials.The cutting temperature is an important parameter in the machining process and is closely related to the deformation of the wafer.However,due to the limitations of the processing environment,the existing testing equipment is difficult to accurately measure the temperature field distribution in the multi-wire sawing process.In this paper,ANSYS software is used to construct the single-wire cutting temperature field model,the sapphire thermal physical properties are actually measured,and the heat flux in the arc region is calculated using the tangential sawing force measured by the dynamometer,then the theoretical temperature field of wafer with single-wire cutting is calculated.In the temperature field,the effect of distribution of coolant and heat flux on the calculation results was analyzed.The infrared thermal imager was used to measure the sawing temperature under different cutting depths and different cooling conditions in the single-wire cutting process.The temperature field model of single-wire sawing was verified by comparing with the experimental results.Based on this,a multi-wire cutting temperature field model was constructed,and the effects of process parameters,sawing wire wear,wafer thickness,and processing materials on the multi-wire cutting temperature field were analyzed.The multi-wire cutting temperature field was used to further analyze the thermal stress and thermal deformation of the wafer.The influence of the saw wire wear and the processing material on the thermal stress and thermal deformation of the wafer was analyzed.By comparing with actual wafer deformation,the influence of sawing temperature on wafer deformation is analyzed.The simulation and experimental results all show that the coolant hardly reaches the center of the sawing arc due to the narrow kerf,so the maximum sawing temperature during the sawing process is approximately at the center of the machining arc.When coolant is present,the sawing temperature increases as the depth of cut increases,but then stabilizes,but the sawing temperature rises linearly with depth of cut without coolant.The coolant has a significant effect on the sawing temperature.When there is no coolant,the sawing temperature rises by approximately10?,but when there is a coolant,the temperature rise is only about 2?.Compared with the experimental results,the error of the established single-wire sawing temperature field model is within 5%.It shows that the established single-wire sawing temperature field simulation model is reliable.The theoretical calculation of multi-wire sawing temperature shows that with the increase of the number of cutting chips,the sawing temperature is obviously increased.The decrease in wafer thickness,increase in feed rate,and increase in slicing speed all increase the sawing temperature.The wear of the wire also significantly increases the sawing temperature.Under the same conditions,the sawing temperature of silicon carbide is lower than the sawing temperature of sapphire.According to the thermal deformation simulation model,for the multi-wire saw,the thermal deformation of the middle wafer was small,and the thermal deformation of the wafers at both ends was large.The calculated thermal distortion was about 1.54um,which was much smaller than the wafer deformation in the actual cutting.This indicates that sawing temperature is not the main cause of wafer deformation.The research results of this project provide theoretical and practical reference value for sawing processing applications of hard and brittle materials.