| Silicon nitride ceramic materials have excellent properties such as high strength,high hardness,low density,high temperature resistance,and resistance to corrosion.Silicon nitride materials are widely used in the fields of aerospace,high-speed spindles,precision machinery,and military equipment.Among them,silicon nitride ceramic bearings and silicon nitride rolling elements are considered to have broad application prospects.Because silicon nitride materials are brittle,hard,and difficult to process,which are often used for grinding.In addition,due to the characteristics of silicon nitride rolling elements,their shape and high-precision requirements,the main processing method is grinding,but low grinding efficiency,complicated processing technology and grinding equipment greatly affect the wide application of ceramic bearings.In this thesis,silicon nitride ceramic balls as the research object,based on theoretical analysis,and aims to explore the high-efficiency and high-precision grinding processing methods of silicon nitride balls,and explore the feasibility of chemically assisted grinding processing based on the chemical properties of silicon nitride materials.Clarify flexible grinding processing methods as the method characteristics,comprehensively apply the method of combining chemical assisted grinding and flexible processing,to explore new processing schemes,and provide guidance for high-efficiency and high-precision processing.Use principal component analysis to clarify the influence of process parameters on surface quality under the new grinding method.The specific research content is as follows:(1)The movement laws of silicon nitride ceramic balls under different grinding methods wear compared and analyzed.The results shows that the uniformity of the grinding track directly affects the overall performance of the ceramic balls during the grinding process.An improved method was proposed and a dynamic model was established.The surface forming process of the silicon nitride ceramic ball was researched,and the two-body wear material removal and three-body wear material removal models were established.(2)A model of the wear removal form was established and conducted experimental research.It is concluded that the wear form transition during the ceramic ball grinding process depends on the critical value.In most cases,two-body wear and three-body wear coexist,and between two-body and three-body wear The formation of the change is related to the the concentration of the load and the abrasive.If the concentration of the abrasive is too low,it will cause irregular and frequent changes in the wear form of the abrasive particles.(3)Using the properties of silicon nitride materials for experimental research,it is concluded that the HF aqueous solution can destroy the original network structure of silicon nitride ceramics,thereby significantly reducing the strength of the ceramic materials.Reasonable control of the corrosion time is conducive to the removal of materials during processing.The greater the concentration of HF aqueous solution,the faster the corrosion rate of silicon nitride ceramics.The corrosion rate of high-concentration HF aqueous solution increases with time,and the corrosion rate of low-concentration HF aqueous solution decreases slightly with time.(4)Based on the flexible grinding processing method combined with chemical auxiliary reagents for ceramic ball processing,the orthogonal experiment was used to conduct experimental research on the ceramic ball blank,and the principal component analysis method was used to determine the degree of influence of the process parameters on the grinding processing quality under multiple target parameters,and then optimize Based on the processing parameters of the new grinding method.Through the research in this article,the grinding efficiency and precision of silicon nitride ceramic balls can be improved,and low cost can be rewarded,which lays a good foundation for the realization of batch and high-precision ceramic ball production. |
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