Automated Analysis of Pulse Types in High Speed Wire EDM

Abstract

The common purpose of hybrid manufacturing processes is the control of different machining principles or material removal mechanisms in order to achieve specific goals as for example maximized cutting rates or optimized surface properties. The hybrid wire electromachining technology known as "High Speed Wire EDM" (HSWEDM) was investigated in this study. Depending on the parameter set, it allows high cutting rates and/or cuts with a repeatable and reasonable surface quality. In order to customize the process to a specific application it is necessary to control the proportions of the material removal mechanisms. For the HSWEDM process, a liquid working medium with medium conductivity is used which contains additives for improved regeneration in the working gap and reduced passivation on the workpiece surface. In this paper typical voltage and current pulse types are detected and identified with known material removal mechanisms like EDM, arcing, ECM and joule heating. For this analysis of pulse types a comparably simple data acquisition equipment is sufficient. The percentage of the appearance of different pulse types is being analyzed and its variation is observed over different parameters like pulse current, fluid conductivity and controller gain. These results are compared to the machining results, namely the cutting rate. Thus, the prerequisites for a control of the material removal mechanisms are available.