Research And Development Of A CNC Micro-milling Machine Tool

The applications of micro-cutting techinique on precision machining of three-dimensional small parts have created a great technology revolution of the micro-cutting field. Different from MEMS techinique and ultra-precision machining technique, micro-cutting technique is an efficient method to carry out high productivity and high precision micro manufacture for micron and meso scale miniaturized parts with traditional machining methods. Ultra-precision machine tool is an important equipment to conduct micro-cutting. However, the domestic development on custom machine used for micro-cutting is still at the initial stage and there is a lack of embed research from machinery system design to micro-cutting mechanism analysis. Although some micro machine developments have been reported at abroad, lots of them are still at the trial-manufacture stage and their correlative technologies are keeping secrets to us.Based on the extensive referring to home and abroad information, the development situation of micro-cutting and micro machine design is discussed in detail, the current research status of micro-milling machining and micro-milling machine design is systematically induced and analyzed, and a 3-axis linked miniature CNC milling machine tool system was successfully constructed for manufacturing of micro products. the overall scheme design of the micro NC milling machine is completed and the whole structure of the machine tool, the overall layout, also the selections and design of the key components(control system, spindle system, feeding system, precision bench vice system, tool cooling system, the processing environment system, fixture and machine base, etc) are established. A micro NC milling machine tool which uses the feed servo system of "high-speed spindle of ceramic ball bearings and oil lubrication, DC servo motor+ball screw+precision grating scale" scheme and the IPC-based three-axis motion control CNC system is developed. the base size of the machine is 194mm×194mm×400mm, the workspace size is 50mm×50mm×102mm and sub-micron machining precision can be achieved.The whole structure design of the micro-machine tool has a significant effect on machining accuracy and the structure design of the whole machine can directly affect the machining precision of the whole micro-milling machine tool.The static analysis and dynamic characteristic analysis of the micro-milling machine's whole structure are conducted by finite element modeling (FEM) analysis method, and whether the whole machine's structural design can meet the machining precision requirement is checked. The research results provide references for the optimal design of the machine structure.To verify the performance of the micro-milling machine tool, positioning accuracy and repeatability of positioning accuracy measurement experiments are conducted and the experimental results show that the developed micro-milling machine tool prototype can achieve micron-level feed and meet the following study of micro-milling machining.Finally, to demonstrate the actual capability of machining of the micro-milling machine tool, a micro NC milling machining experiment is conducted.