Development and application of a prototype micro EDM machine

Miniaturization of instrument and device has changed the world greatly. Miniature instrument and device are composed of micro parts and microstructures. The realization of micro parts and microstructures calls for high micro machining capabilities. Micro electrical discharge machining (EDM) has earned its place in the field of micro machining because of its machining without contact and high ability to machine micro 3D structure, and has found wide application in industry. In this paper, a precision micro EDM machine is developed to improve micro machining capability of micro EDM. The machine adopts some high and new technologies. It consists of high precision XYZ stages with the resolution of 0.1 μm driven by linear motor, a high speed rotary spindle with rotation accuracy within 1 μm, high precision granite base which can decrease stray capacitance, small energy power unit and video microscopic system with high enlargement factor which is used to monitor the state of machining online. This prototype realizes a fast frequency of 50 Hz and a highest speed of 10 m/s in each of the X-, Y- and Z- axes, which improved micro machining capability remarkably. Experiments show that micro shafts with the diameter of less then 5 μm are ground by using block electrode, micro holes with the diameter of 10 μm and micro slots with width of 15 μm can be obtained steadily. At last, a complicated 3D microstructure is machined via EDM technology on this machine.