| A long series of problems that ceramic tile broken by vibrating of polishing head and bad machining quality of ceramic tile surface are created in the process of ceramic tiles polishing. Dissertation for the doctor degree in engineering should zero on the problem of ceramic tile machining. Author based his research results on grinding theories and machinery vibration theories surface polishing formation mechanism of ceramic tile and polishing head dynamics character of polishing machine are studied by combining theories modeling with testing. The grinding processes are optimized to realize low damage, high precision and cost-effective machining of ceramic tile surface. The theoretical and experimental results add a great value to the ceramic tile surface in terms of industrial application.Research contents are as follows:Based on the literature reviews, the dissertation puts forward the preliminary analysis for the guideline of surface polishing formation mechanism of ceramic tile and polishing head dynamics character of polishing machine, as well as the train of thought for studying it. The dissertation comprehensively introduces the scheme for the experimental study in surface polishing formation and polishing head vibration of polishing machine.Movement characteristic of polishing head is analyzed and three-dimensional complex movement tracks equations of polishing head are constructed one by one based on the structure and working principle of polishing machine and polishing head. From these research, it can be concluded that the mechanism of polishing head machining ceramic tile. Research results indicate that essential principle of polishing head machining ceramic tile by combining turning cutting with impact fracture.The polishing block is turning on its axis and at the same time orbiting round the axis of polishing head, following polishing head movement up and down at vertical direction. Geometry equations of polishing head are constructed based on space analytic geometry. Geometry equations of polishing head adapt composite cylinder coordinate system. From above, speed and accelerated speed equation of any grains on polishing head are constructed based on geometry equations of polishing head. The research results reveale that quantify relation between positions of any point on polishing block and the location angle and height of polishing head, the location angle of polishing block, and factors of influencing polishing head rotate speed are obtained.Theoretical analysis is conducted on exciting force of polishing head generation process and polishing block system. Vertical direction dynamics model of polishing block system are established. Then, vibration reduction mechanism of polishing block system is discussed and vibration reduction dynamics model of polishing block system are established. The research results indicate that the vibration of polishing head in vertical direction is principal cause that broken ceramic tile, the ability of reducing vibration is very effective by inertia counter-force of polishing block swing counteracted disturb twist moment of polishing head.Polishing lines of ceramic tile is used as the research objects. A comprehensive experiment is designed to observe the formation process of the glossiness surface. Surface morphologies, surface structure, and surface glossiness at each process ranging from calibrating to nanodroplets coating are monitored. From scanning electron microscope observing and glossiness testing, it widely research that the surface formation mechanism of ceramic tile. The research results indicate that the surface formation mechanisms of ceramic tile in different process are found and surface scratches distributions of ceramic tile are obtained.Finally, the experiment is carried out; the vibration accelerations of polishing head in different machining acceleration are researched widely. Four factors:the polishing head speed, swing speed of polishing head, polishing head forces and grain size of grinding block are taken from machining parameters of polishing head as the research objects. Four levels are taken from every factor as the research objects. Vibration experiments of polishing head about four factors four levels and three factors four levels are developed by orthogonal design. According to these experiment results range analysis, it can be obtained that swing speed of polishing head, polishing head forces and grain size of grinding block have an effect on vibration of polishing head.The research results of this thesis provide a theoretic base for polishing head design in actual production, production condition is optimized, performance of polishing head can be better. |
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