Pulse discharges ignited by the use of conductive flour composite resin electrode in a dielectric liquid (II)

Abstract

This paper presents the development for the method of EDM by using flour composite resin electrode. Multi-arc spots phenomena which take place during the course of one short current pulse by use of the composite electrode at least as one side of electrode has been discussed in our previous study.
Bulks of this composite resin are prepared by means of hot-press method at 190°C after mixing up copper or carbon flour with methacrylate resin.
The former composite resin in particular causes a good result to keep the repeating pulse discharge in stable, and micro-craters formed by the pulse discharge are dispersed all over opposite metal face homogeneously. The result shows that this composite electrode might have a superior property for the industrial electrode material for EDM. When using the latter composite electrode, micro-craters are dispersed heterogeneously and sometimes concentrated in limited area. The result indicates that this electrode may be rather inferior for the electrode material.
The discharge current which belongs to small energy level pulse ignition, less than one ampere and micro-second ordered pulse width, can carve some letters or curved line on the opposite steal surface without any heating effects. Higher level discharge current which has more than several amperes current and milli-second ordered pulse width can cause the steal surface to make obvious effects of heat hardening, although flour composite resin electrode has low temperature softening point at most below 200°C.
But these resin electrodes have a big failure of wearing itself, because of the fact that the ratio of wearing amount is rather plenty as 4-10 times for the ratio of weight loss for FCR/steal. These experimental results show that the composite resin electrode makes a possibility of useful applications to some industrial fields because of the easy preparation of electrodes.