| The miniaturization of machine components plays a very important role in the future technological development of a broad spectrum of products owing to various advantages: low material cost, portability, implant, lower power consumption and higher heat transfer since their surface-to-volume ratio is very high. Micro-milling is a broad micro-machine technology, but its surface quality is relatively bad, because of the effect of the minimum chip thickness, the radial run-out of the micro-milling cutters, tools'worn and adhering chips, and the anisotropy of poly-crystal metal material. Whereas the better surface quality can be gained in the grinding process, the grinding process is applied to the micro-machining which is called micro-grinding to improve surface quality in micro-machining.This thesis is an attempted and exploratory research concerning micro-grinding, and it focuses on the practical process of the. micro-grinding, the difference between micro-grinding and traditional grinding and the comparison to the micro-milling. The micro-grinding process is researched in the following aspects:The micro-grinding machining system and the manufacturing processes of micro-grinding tools are the first aspect of the research of micro-grinding process. The micro-grinding machining system is researched, and the former micro machine tool (MMT) is improved to enhance its performances to be satisfied the requirements of the micro-grinding process. After making a balance on several micro-grinding tools'manu-facturing processes, we choose the Cold Gas Dynamics Spraying technology (CGDS) by which we can spread the tiny CBN grits on small columns to manufacture micro-grinding tools. The dimension of the micro-grinding tools is measured and there are some errors in them. The dimension errors of the micro-grinding tools will make a worse effect on the micro-grinding quality.It is made that a particular research on the method of micro-grinding by which the workpiece must be milled at first, so the workpiece can be located accurately in the micro-grinding process. The material AL-6061-T6 spring-back of elastic variation in the cutting zonc is studied and measured. We find the relationship between the spring-back of elastic variation and the parameter of micro-milling process. The different micro-tools'tip must be precisely superposition after replacing micro-tools. We exploit a method by laser displacement sensor to accurately poison the micro-tools'tip on axial and radial position, and it will realize the multi-procedure micro-machining.The characteristic of surface micro-grinding is analyzed. The micro-grinding tools are so small that there is a tremendous difference between micro-grinding and traditional grinding in the geometrical model and the speed of micro-grinding tools is too low. The influence of micro-grinding tools'dimension parameters on the efficiency and quality of micro-grinding is analyzed, and we find that the micro-grinding quality is better at the small grinding thickness, lower feeding speed of workpiece and higher grinding speed. Also the micro-tools with smaller grits which are spread densely can make a better quality, but the efficiency is low. We can improve efficiency of micro-grinding by moderately enlarging the dimension of the micro-tools and increasing the spindle rev. The mechanics of single grit cutting material at low grinding speed is briefly discussed.The characteristic of surface quality micro-grinding 20# steel is observed in micro-grinding experiment. The relationship between the factors which include the micro-grinding tools'dimension parameters and the micro-grinding process parameters and the micro-grinding surface quality is analyzed. The micro-grinding surface quality is contrasted to The micro-milling one.Finally, conclusions are drawn and some problems in experiment are illustrated. Some recommendations for future are provided. |
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