Design of a High Dynamic Piezo Module for Resource-efficient Electrothermal Precision Ablation

The applications in micro-EDM often require a high process-stability, which is determined by the dynamic characteristics of feed-system and process-control. Many industrial EDM-machines cannot sufficiently realize this high dynamic. Usually, knowledge about the basic EDMsystem is limited and is only comprehensible by analyzing the voltage-and current-curves. Therefore, additional hardware-and software-systems have to be implemented to comply with these demands. In the present study, a solution is presented which superimposes the basic-system, consisting of feed-system and process-control, with an additional-system, which includes a piezo-actuator. For this piezo-actuator, a separate process-analysis and a separate feed-control is developed. Improvements in the process-stability as well as requirements demanded by the additional-system are shown. In the future, the presented solution can be implemented into industrial EDM-machines, especially if very small and lightweight workpieces have to be machined with high precision. The essential issue in combining two control-and feed-circuits is to prevent deteriorations in machining. By the help of a selected example of machining a contour by micro-EDM, it is shown how the additional-system ensures a high process-dynamic and thus reduces the number of inefficient pulses. This way, productivity and machining-precision are improved. The reduction of inefficient pulses and process-anomalies is verified by an analysis of voltage-and current-curves. In collaboration with the additional-system, the basic-system performs the main feed of the electrode assembly. (C) 2018 The Authors. Published by Elsevier B.V.