| Ceramic materials have excellent properties such as high hardness,strong wear resistance and low expansion.In recent years,their applications in high-end fields such as national defense have been increasing,and the processing environment and processing quality requirements have become more and more demanding.In some scenarios where conventional wet grinding cannot be used,due to the low plasticity of ceramic materials,the dry grinding process leads to low overall processing quality,fast grinding wheel wear and easy blockage,and it is difficult to achieve high-efficiency and high-quality grinding.It also limits the further promotion and application of ceramic materials.Therefore,it is a very meaningful work to explore the highefficiency,high-quality and low-cost dry grinding process of ceramic materials.This paper takes ZrO2 ceramics as the research object,applies the ultrasonic vibration machining technology to the research of material grinding performance,and proposes a new type of dry centerless grinding technology(Ultrasonic-vibration dry centerless grinding,UDCG)using composite ultrasonic vibration.At the same time,a higher grinding surface quality and a lower percentage of the blocked area of the grinding wheel are obtained.The main research contents are as follows:(1)The UDCG system is designed and constructed,and the ultrasonic vibration and its working principle are introduced in detail.A luffing device matching the frequency of the transducer is specially designed and manufactured,and the modal and harmonic response simulation analysis of the luffing device is carried out through the Workbench finite element analysis software.And use impedance analyzer and digital displacement tester to test the vibration performance of UDCG system.(2)By analyzing the kinematic characteristics of UDCG,the ultrasonic elliptical vibration and composite vibration trajectory of ZrO2 ceramic specimens were simulated respectively,and the range of UDCG vibration amplitude under different vibration angles was calculated.According to the vibration kinematics characteristics of the specimen,the relative motion trajectory equation of the abrasive grains and the actual grinding depth of the abrasive grains are studied,and the circular model of the centerless grinding specimen is established.(3)The proportion of the blockage area of the grinding wheel in the ZrO2 ceramic processing process was obtained by the general dry surface grinding test instead of the conventional centerless grinding process,and the grinding parameters(grinding depth,grinding wheel linear speed and The influence of grinding wheel feed times)on the clogging of the grinding wheel,and the influence of the clogging of the grinding wheel on the grinding quality(grinding temperature and surface roughness of the specimen).Compared with the composite ultrasonic vibration dry grinding process performance,the test shows that the composite ultrasonic vibration dry grinding process can reduce the surface roughness Ra value of the specimen after grinding by about 14.15%,and reduce the proportion of the blocked area of the grinding wheel by about 8.24%.(4)Carry out ZrO2 ceramic UDCG test.Combined with the test results,the grinding performance of conventional centerless grinding process,composite ultrasonic vibration dry surface grinding,UDCG and elliptical vibration dry centerless grinding was compared,and the round model of the test piece was verified.The research results show that using the UDCG process proposed in this paper,the blocking area of the grinding wheel is about 5.06%,the surface roughness Ra of the test piece is about 0.176 μm,and the surface grinding temperature of the test piece by thermal imaging is about 27.3℃.The degree of runout is about 12 μm.Compared with the optimal test result of the conventional centerless grinding process,the blockage area of the grinding wheel is improved by 17.28%,and the surface quality of the test piece is improved by 17.92%.A new and more effective method is provided for grinding ceramic materials. |
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