Study On Theoretical Model Of Cutting Force And Surface Quality Of Special Ceramics

Special ceramics had received extensive attention for their superior properties such as high hardness,high temperature resistance and corrosion resistance.However,ceramics were typical brittle materials,and there were some problems in the process of processing,such as low efficiency,high cost,difficult to guarantee the quality of processing,which limit the wide application of special ceramics.Turning ceramics had the advantages of high efficiency and low cost,so it had a good prospect.But at present,there were few researches on ceramic turning,the removal mechanism was not mature,and the theoretical model of cutting force need to be improved.In this paper,the removal mechanism of ceramic turning materials was studied,the theoretical model of cutting force was established,and the machined surface quality was studied.The work of this paper was mainly embodied in the following aspects:1.Based on the kinematics analysis of ceramic turning process,the material removal thickness was put forward.In this paper,the influence of the relationship between material removal thickness and the tool tip arc radius on the mechanism of ceramic turning fracture removal was studied.The crack deflection angle model was established with indentation theory to determine the crack propagation path of large-scale fracture.2.The process of ceramic turning material removal was regarded as the process of crack propagation.The energy conservation relationship between tool input and crack system was established.The concept of brittle fracture energy of brittle materials such as ceramics was proposed based on Griffith theory.The theoretical model of cutting force for a large-scale fracture was established and verified.The model had high accuracy under the condition of brittle removal.3.Through single factor and orthogonal experiments,the influence of cutting parameters on cutting force was studied.It was found that cutting force decreases with the increase of cutting speed and increases with the increase of feed rate and cutting depth,and the cutting depth had the greatest influence on cutting force.4.By studying the surface quality of ceramic materials,analyzing the formation mechanism of brittle removal surface,the theoretical model of brittle removal surface roughness of special ceramics was established,and the trend and primary-secondary relationship of surface roughness with cutting parameters were verified by experiments.Simple process parameters were optimized by orthogonal experimental analysis.