Study On Ultra-precision Grinding Technology Of Hard And Brittle Materials For YG3and TN85

With the development of modern science and technology, hard and brittle materials are widely used in the fields of cutting tools, automotive, moulds and precision optical instruments, because of their excellent performance of high hardness, good resistance to high temperature, wear, corrosion, light weight and nice self-lubricating.Due to the brittleness of the materials, it is easily broken and cracked when it is machined. In order to obtain the super smooth surface without the damage, ultra-precision ductile grinding is used to machine the hard and brittle materials. Therefore, the study on ultra-precision grinding of hard and brittle materials has great significance.This subject is supported by the Special major for science and technology (high-end CNC machine tools and basic manufacturing equipment) of ultra-precision CNC machine tool on micro-aspheric optical lens mold about "nano-mirror grinding research for super hard difficult-to-machine materials". The paper mainly focus on the ultra-precision maching of plane and spherical moulds and its main contents are as fllows:(1)Based on the current process theory and the related background about hard and brittle materials, it summed up the deficiency of the existing processing technology, and proposes a maching method of spherical surface by a forming wheel grinding with the inclined axis.(2)According to the special properties of hard and brittle materials, ultra-precision ductile grinding is used to machine the materials. The inclined-axial setting angle mathematical model is established to optimum the inclined-axial setting angle, and it is beneficial to achieve the ultra-precision mirror surface.(3)Through the experiment of the surface grinding, comparing and analyzing the measured surface roughness and micro-surface morphology, considering the grinding efficiency and effectiveness, the process parameters are optimized and applied to the spherical surface grinding test to obtain the nanometer machining surface.(4) Through the analysis of the effect of different types of wheel wear on the machined surface, the reasonableness of a diamond grinding wheel for ultra-precision grinding of hard and brittle materials is proved. Through the test on the spherical by forming wheel inclined-axial grinding with micro-feeding, and the analysis of the effect of this mode on the machined surface, the correctness of the model of the optimal installation angle is further verified.