Evaluation of the Process Performance in Wire EDM Based on an Online Process Monitoring System
Ugur Küpper, Tim Herrig, A. Klink, D. Welling, Thomas Bergs
Abstract
The wire EDM process can be evaluated according to various criteria. In addition to the generated component quality, the cutting rate is a key performance index for the main cut. Process stability is another evaluation factor. It is defined by a resulting constant feed rate during machining and a low probability of occurrence of wire breakages. In several studies, the discharge distribution has been analyzed to predict a wire breakage. Due to the high discharge frequency, the analysis of the electrical signals has been conducted only for very short time periods. A quantitative evaluation of the continuous wire EDM process could therefore not be carried out. By implementing a real time process monitoring system, the detection of single discharges and the allocation to normal and abnormal discharges can be conducted. By using a FPGA (Field Programmable Gate Array), the characteristic discharge parameters can be analyzed in real time. The monitoring system stores only characteristic numbers and thus a continuous process can be recorded without generating a large data volume.