Investigation On Simulation Models Of Morphology And Damage Depth During Precision Grinding Of Leucite Glass Ceramics

With the continuous improvement of various glass-ceramic systems,glass ceramic has become one of the most potential ceramic materials.Leucite glass ceramic has high mechanical strength,fracture toughness and biocompatibility,and is usually used as highperformance denture materials.However,as a typical hard and brittle material,leucite glass ceramics is hard to machine.Surface and subsurface damages are easy to be found in the grinding process,which affects the performance of the material seriously.In order to improve the precision grinding quality of leucite glass ceramics,the investigation on removal mechanism during the precision grinding is needed.Firstly,the mechanical properties of leucite glass ceramics at nanometer and submicron scales were obtained by quasi-static nanoindentation tests.The elastic recovery rate,hardness and elastic modulus of the material were calculated.Through the nano scratch tests,the effects of different scratch parameters on material removal were investigated,and the brittle-plastic transition phenomenon was analyzed.The results indicated that the plastic removal and brittle removal of the material occur simultaneously during the grinding process,and both participate in the formation of grinding morphology.Secondly,in the Jupyter-Notebook environment,the calculation of grains shape,grains position,elastic-plastic / brittle-plastic transition depth and grains cutting depth during precision grinding process were completed,and the deformation and removal methods of the material under different grinding parameters were analyzed.The grinding force model of the workpiece and the simulation model of the material surface morphology in the precision grinding process were built,respectively.The damage depth model of the subsurface during precision grinding were built based on the theory of fracture mechanics.Finally,the precision grinding experiments of leucite glass ceramics and zirconia reinforced lithium silicate glass ceramics were carried out.Multiple sets of single factor experiments were designed to explore the effects of different grinding parameters during the grinding process.The models of force,surface morphology and damage depth of subsurface were verified.The results indicated that the size of grains,feed rate and grinding depth all affect the quality of precision grinding,and the influence degree decreases in turn.The simulation models reflected the actual processing situation well,and could be used to guide the precision grinding of materials.