In order to improve machined surface quality and reduce the deformation, the residual stress involved in cutting titanium alloy was studied under different cutting speed and cutting depth by finite element simulation method. The results indicate that the increase of cutting speed and cutting depth are helpful to the surface residual compressive stress generating. However the increase of cutting speed also leads to the increase of surface residual tensile stress, the effect degree is relatively small. It is required to select higher cutting speed and smaller cutting depth to improve the surface stress state and reduce the unexpected distortion.

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With the development of aviation and aerospace industry, the performance requirement and part accuracy requirement of aviation engines are increasingly enhanced, and it is difficult to ensure machining accuracy and usage requirement by traditional machining technique. Therefore, the cutting performance and cutting parameter of aviation engine thin-walled parts are researched. Based on FEM (Finite Element Method), simulate cutting of titanium alloy thin-walled parts and analyze the cutting process of a three dimensional model under different cutting parameters so as to obtain the rules of the residual stress and deformation of titanium alloy thin-walled parts. The method referred to in this paper can be used to select the machining parameters of real aero-engine thin-walled, which is helpful to control deformation of workpiece and increase the machining efficiency.

Isotropic pyrolyric graphite (IPG) is a new kind of brittle material, it not only has the general advantages of ordinal carbonaceous materials such as high temperature resistance, lubrication and abrasion resistance, but also has the advantages of impermeability and machinability that carbon/carbon composite doesn’t have. So it can be used for sealing the aeronautics and astronautics engines turbine shaft and the ethylene high-temperature equipment. The mechanism of this material removal during the precision cutting was analyzed by using the theory of strain gradient. The critical cutting thickness of IPG was calculated for the first time. Furthermore, the cutting process parameters such as cutting depth and feed rate which corresponding to the scale of brittle-ductile transition deformation of IPG was calculated. The prediction model of surface roughness in precision cutting of IPG was developed based on the Genetic algorithm. Using the surface roughness prediction model, the study investigates the influence of the cutting speed, the feed rate and the cutting depth on surface roughness in precision turning process was researched.