Research On Self-Rotating Ultraprecision Grinding Force Model And Surface Quality Of Ultra-Thin YAG Crystal

With the increasing application of all-solid-state lasers,higher and higher requirements are put forward for the surface quality of its core component-laser crystal.At present,grinding and polishing methods are mainly used to ensure the surface quality of laser crystals,but the processing efficiency is quite low.Therefore,it is of great significance to study high-efficiency and high-quality laser crystal ultra-precision processing technology.In this paper,yttrium aluminum garnet(YAG)single crystal is the research object,and the grinding force and surface quality in the grinding process were studied based on the self-rotating grinding method.The aim was to obtain an effective and efficient ultra-precision grinding process for laser crystals.First,a model of YAG crystal self-rotating ultra-precision grinding force was established.Started from the grinding analysis of a single abrasive particle,it was pointed out that the cutting depth is the direct factor that determines the material removal method.The cutting depth of abrasive grains was obtained according to the method of material removal by self-rotating grinding,and the corresponding grinding force models under plastic domain grinding and brittle domain grinding were established by combining elastoplastic mechanics and fracture mechanics.In the establishment of the model,the influence of the distribution of abrasive particles,the elastic deformation of the workpiece material and the grinding wheel bond and the strain rate effect were comprehensively considered.Secondly,the warpage of ultra-thin YAG crystal self-rotating ultra-precision grinding was studied.Combining finite element and theoretical analysis,a self-rotating grinding warpage model was established.The model considered the influence of subsurface damage depth and machining stress on the degree of warpage of the workpiece.The problem of edge chipping in self-rotating ultra-precision grinding of YAG crystal was studied.Through finite element and theoretical analysis methods,the influence of edge shape and cutting depth on the propagation of brittle cracks and edge chipping was analyzed.Based on the classical brittle crack system,a theoretical model of edge chipping was established,and the influence of strain rate on the degree of material edge chipping was taken into consideration when establishing the model.Finally,a grinding experiment was carried out to verify the warpage and edge chipping model established,and the grinding force model was indirectly verified by establishing the relationship between the grinding force,the workpiece warpage and the workpiece edge chipping model.Through experiments,the influence of grinding parameters on warpage,chipping and surface roughness was obtained.Based on experiments and models,a self-rotating grinding process plan suitable for laser crystals was designed,which comprehensively considered the machining efficiency and surface quality.A smooth surface that meets the requirements was obtained.This result has certain guiding significance for high-efficiency ultra-precision grinding and processing of laser crystals.