Study On Methords For Detecting Micro Edm State

With the increasing demand for tiny devices and the development of MEMS (micro electro mechanical system) technology, Micro-EDM has brought scholars to pay attention on it more and more. It is widely used in aerospace, medical, mold, micro-electronics devices, biotechnology, micro-sensors and micro-electrical manufacturing and so on. Accurate, stable and efficient micro-EDM system is always researchers pursuit of. Discriminating system for discharging status is the key parts of machine tool servo system which is a necessary condition for stability machining. So Develop a new discriminating system for discharging status is of great significance.First, this paper introduces the status of micro-EDM and the discriminating systems, elaborated on the principles of traditional discriminating systems for discharging status. At the same time, aim at the new machine tool, we study the discharge characteristics when it's machining. By this, we make the difficulties for discriminate discharging status more clearly: it is hard to distinguish the ruleless voltage when machining. To solve this problem, we find that it is easy to distinguish the current state by voltage comparator. through the output of compator, the high level means no discharging between electrode and workpiece while low level means discharging. Using RC low-pass filter to filtrate the output of voltage comparator, the reaction of RC moudle can reflect the discharging status.According to this idea, we accomplish the hardware and software design for the new discriminating system. We use PIC monolithic microprocessor for data processing and transmission, and verify the stability, accuracy of the whole system. The correct working status of the system depends on the correct reference voltage of the voltage comparator and the parameters of RC module. This paper use a large number of experiments and do the waveform of voltage analysis to select related parmeters in different conditions. Experiments shows that the new detection system can reflect the discharge status while machining. Apply this new discriminating system to the lab machine tool, the discharging status are more stable. By machining tiny holes and comparing with the old, the efficiency of the machine tool has been greatly improvd. It shows that with the new discriminating system, the micro electrode can be easily processed into 20 micron.