Research On Laser Heat Assisted Grinding Technology For Hard And Brittle Material

This topic is based on the typical non-metallic hard and brittle material quartz glass and the typical metal hard and brittle material Hard alloy YG20.Quartz glass is often used as a precision optical component.Hard alloy YG20 is often used as a base for molds.Their application requires extremely strict surface quality.However,due to the hard and brittle nature of materials,traditional machining results in poor surface quality,serious tool wear and other phenomena As an advanced composite processing technology,laser heat assisted grinding technology is a feasible method for efficiently processing hard and brittle materials.In this paper,the research methods of theory,simulation and experiment are combined.Firstly,the related mechanism of grinding is systematically studied.Then the temperature distribution of the surface of the material under laser scanning is studied.Finally,according to the principle of laser heat-assisted grinding and existing laboratory conditions,laser heat-assisted grinding experiments were carried out on quartz glass and Hard alloy YG20.The surface roughness,surface morphology and tool wear of quartz glass after laser heat-assisted grinding were systematically studied.The surface roughness,surface morphology and surface microhardness of Hard alloy YG20 after laser heat-assisted grinding were observed.The main research contents of this thesis are as follows:(1)The removal model of hard and brittle materials is expounded,and the theoretical research and formula derivation of undeformed chip thickness,surface roughness and subsurface crack depth are carried out.(2)The thermal effect of laser and material interaction was studied.The mathematical thermal model of the surface temperature distribution of quartz glass under laser scanning was established.The thermal effect of quartz glass under laser was studied by ANSYS finite element analysis.The effects of laser scanning speed,laser power and laser spot radius on temperature distribution were compared.Then the correctness of the mathematical thermal model and simulation results was confirmed by further temperature measurement experiments.(3)For quartz glass,four-factor and three-level orthogonal experiments and corresponding contrast experiments were designed,and experimental research on wheel wear was also made.The study found that laser heat-assisted grinding can improve the surface quality of quartz glass,realize the plastic domain grinding of quartz glass,and reduce the wear of the grinding wheel.(4)For Hard alloy YG20,the experimental scheme of temperature measurement and grinding single factor parameter determination was designed,and the surface microhardness of Hard alloy YG20 after laser heat-assisted grinding was detected.The results show that compared with the traditional grinding process,the surface quality of Hard alloy YG20 after laser heat-assisted grinding is improved,but the complete plastic domain grinding of the Hard alloy YG20 is not realized.In addition,laser heat-assisted grinding of Hard alloy YG20 materials does not result in obvious work hardening and change the properties of the material.