Study On Key Factors Affecting Cutting Mechanism In Granite Processing

With the rapid development of building decoration industry,the granite,marble and other natural stones with hard wear-resisting,rich colors and bright like a mirror are very popular with the people,and the output and consumption of domestic stone decoration has reached NO.l for many years in the world,however,the granite due to high strength,high hardness,high brittleness and high abrasion resistance are difficult to machine.At present,the diamond tool is used on the granite milling process to achieve high precision machining,and milling performance of diamond tools will directly affect the machining quality,efficiency and cost evaluation.The milling force of diamond tool is taken as the main evaluation parameter of milling performance,and the milling process is actually interaction between diamond particles on diamond tools and materials particles to achieve the material removed.Therefore,the study of single particle and particle sequential cutting is an important means to understand the complex milling process.In this thesis,granite milling process was taken as the research object.From the micro view of single particle cutting and cutting sequence,the effects of different processing parameters on the cutting force,the mechanism of material removal,surface processing quality were analyzed by the numerical simulation technology and the scrath test.The research contents included the following aspects:First of all,the research status of hard brittle materials and micro machining was obtained from literature review,the properties of materials and fracture forms for granite were summed up,and the suitable mechanical crushing model and theoretical mechanical model was choosen,which provied a reliable theoretical basis for further research on the milling.Secondly,the numerical model of diamond particle cutting granite was established by ANSYS/LS-DYNA,and the influences of parameters such as particle entry form,cutting angle,cutting speed and cutting depth on the cutting force were analyzed by single factor method.The particle cut angle,cutting speed and cutting depth were chosen to design three factors and three levels orthogonal test table.The numerical simulation and extreme analysis showed the influence degree of above three factors on cutting forces had the order of cutting depth,the particle cut angle and cutting speed,and the variance analysis showed that cutting depth and the angle had a significant influence on the cutting force,and in the low speed range,the cutting speed was basically no influence on cutting force.Thirdly,the static pressure scratch test of different kinds of granite specimens was carried out,the change of cutting force under different depth and specimen speed was analyzed,and the reliability of the numerical model was verified.Combined with numerical simulation,the brittle plastic deformation,removal mechanism,surface sub damage degree and residual stress distribution for granite during milling were deeply studied.In this thesis,the diamond particles micro cutting of granite are analyzed deeply.Based on the theoretical model,numerical simulation and pressure scratch test,the influence of different processing parameters on cutting force are investigated,and the removal mechanism,surface damage degree,the residual stress distribution are also analyzed,which could provide a certain theoretical basis for the optimization for processing parameters in granite milling.This study has universal application significance for the processing of hard brittle materials and also important practical value.