Research On Micro-EDM Processing System Using Hybrid-Grinding With Wheel And Wire Electrode

Micro electric discharge machine (MEDM) is an important research area in nontraditional material removal processes. Because workpiece and electrode don't contact to each other in this technology, there is no mechanical stress between them. For this reason, the technology has huge potential capacity in the manufacture of micro shafts, holes and three dimensional structures. However, the processing speed of wire electro-discharge grinding (WEDG) is so slow that it limits the speed rising of electrode making seriously. Therefore, in order to introduce this technology widely, we must solve the problem of electrode making.In this article, the author analyzes the advantages and disadvantages of each method in electrodes making now, then invents a new electrode making method which combines wire electro-discharge grinding and wheel grinding. At last, the author discusses micro electric discharge machine servo system and on-line detection system used in the machine.The motion controlling core of this equipment is a data acquisition card which be combined with personal computer, servo motor and grating-feet to realize precise movement. In order to reduce the non-normal discharge, the author develops a new independent power supply, whose stability of the waveform improved greatly. Precise rolling bearing was also used by author to achieve high precision rotary of spindle and simplify the structure of spindle. Besides that, the author overcomes the capturing of digital image by CCD, image capture card and microscopy equipment. Then the author realizes the on-line testing of electrode shape which provides evidence for processing parameters'setting, through digital image processing, pattern recognition and fitting algorithm. The servo strategy in different working modes is also be analyzed by authors too. Finally the author explores the reason why processing system errors exist in micro electric discharge machine based on experiment data.In the article, one micro electric discharge machine has been developed. The author uses this machine to do some typical experiments, such as wheel grinding, wire electro-discharge grinding, hybrid-grinding, micro-hole manufacturing, nozzle manufacturing. Those experiments show that the hybrid-grinding rises speed ten times compare to wire electro-discharge grinding. The new idea in electrode making is proved to be true. Besides that, the author makes micro shafts aboutΦ15μm and micro hole aboutΦ50μm with this machine.