Study On Micro Cutting Technique For High-Accuracy Miniaturized Components

High-accuracy miniaturized devices and components, including MEMS, are increasingly in demand for various industries. Micro processing techniques are vital for their development, and become a trend of global machining techniques. Because of the variety of the components and the special properties of each micro processing technique, it is very important to select proper formation techniques.Comparing with the other micro processing techniques, micro cutting technique possesses the advantages of high efficiency, high accuracy and low cost, so it is most suitable for processing micro components with complex three dimensional structures and curved surface. The material that can be cut includes variable metal material and nonmetallic material, including composite material, plastic, and ceramic. Micro milling technique is one of most flexible micro cutting techniques, which uses small-diameter milling tools for micro cutting process on machine tools with the high-rotation-speed spindle. Design of micro tool geometry and cutting process control are key factors for the application of the technique besides precision requirements of machine tools, of which especially micro tool structures and tool wear. With the decrease of tool diameter, partial wear and fracture of tool edges will easily occur for increase unit force on cutting edges, which will lead to decrease of cutting ability and affect precision of workpieces.With the great variation and small batch-size of workepieces fabricated by micro milling technique, such as high-precision electrodes, small three-dimensional cavities and patterns, common commercial milling tools do not fit the requirements, thus, the specialized non-standard tools are commonly used. As the tools are often fabricated from tool bars on common tool grinders, design and fabrication technique of them become very important. Based on experimental analysis of carving tools, the new type of single-flute and two-flute tools with tapered-shape are modified and designed, referencing structures of turning tools and carving tools. The fabrication technique and device for tools are analyzed, and the tools are fabricated on a common tool grinder. New type of tools is designed.Micro milling experiments of copper and 45steel are carried out with new type of tapered-shape tools, and investigation is done on the relationship between surface roughness Ra and various factors, such as cutting speed, feed speed and feed direction including up-milling and down-milling operations. The investigation analyzes the effect of micro tool geometry on micro milling quality, and offers direction for tool design and selection of cutting properties. The properties and applicability of micro milling processing with this type of tools are analyzed, by micro milling experiments of small-size workpieces.