| Zirconia is an inorganic material, which has excellent electrical properties, abrasion resistance, high temperature resistance corrosion resistance and wide application field. At present, zirconia is mainly used in the field of ceramic which is also called medical zirconia ceramic. It is one of the best bio-tech materials. As the repair material, zirconia ceramic has many advantages such as high strength, high toughness, good biocompatibility and high similarity of performance and aesthetic effect of processed dentures to real dentals. However, compared with the metal material, medical zirconia ceramic is easy to crack because of the exist of thermal stress, cutting force and other factors in the cutting process, which will reduce its fracture toughness and bending strength. Therefore, it is necessary to strengthen medical zirconia toughening ceramics technology and develop new process.The manufacturing methods of ceramic material include cutting, grinding, polishing and hole processing. Grinding with diamond wheel is the common method in these methods. However, because of its high hardness and brittleness, it is difficult to be processed. The most parts by grinding the ceramic material will produce various types of surface/sub-surface damage. The processing costs will be reduced using great material removal rate. Therefore, the important goal of ceramic grinding is to ensure enough surface integrity and dimensional accuracy while the maximum material removal rate is obtained.In this paper, grinding performance, grinding mechanism and the factors affecting the grinding performance of ceramic materials are mainly studied according to the grinding performance of medical zirconia ceramic. Then, the model is builded based on the simulation theory. Finally, the specific experiments are conducted.The main contents are as follows:1.According to the single particle cutting theory and fracture mechanics, the model of medical zirconia ceramics’s grinding process is builded. The zirconia ceramic constitutive relation is analyzed and described during cutting process. Its orthogonal cutting process is analyzed by the ABAQUS software. Then, stress nephograms and grinding forces are obtained in different cutting speed and cutting thickness. The simulation analysis has a certain significance for optimization of process parameters.2.Medical zirconia ceramic grinding performance test and analysis:Removal mechanism of ceramic materials are different from ordinary metallic materials.medical zirconia materials testing and refining coarse grinding forces shaping the surface roughness test are conducted, using appropriate processing equipment and laboratory equipment after clearing the removal mechanism. The test results are analyzed by the orthogonal experiment method. The influence of experimental parameters on the test results is cleared. Which provide a reference for subsequent grinding dental restorations. |
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