Model based determination of the influence of process parameters on the lateral working gap and electric current in pulsed electrochemical machining

The further development and optimization of products include miniaturizing components and increasing functional integration to reduce resource and energy consumption. One manufacturing method for the processing of metals is pulsed electrochemical machining (PECM) with an oscillating cathode. In this process, the workpiece material is removed through anodic metal dissolution at the interface to an electrolyte. One process variant of the PECM is the shaping via the lateral working gap. This paper presents a method for identifying and evaluating the influences of relevant machining parameters – including gap voltage, pulse duration and oscillation frequency, cathode feed rate and height of the inner cathode surface – on the resulting lateral working gap and electric current in PECM for the manufacturing of external geometries made of hardened tungsten high-speed steel. Numerous experiments are conducted and evaluated using design of experiments (DoE) approach. Subsequently, multiple linear regression models are derived. These models are used to determine the functional relationships between the machining parameters and the resulting lateral working gaps and electric currents. Moreover, the primary and interacting effects in pulsed electrochemical machining with an oscillating cathode are quantified through a global sensitivity analysis. The results demonstrate that both the lateral working gap and the electrical current are influenced by changes in the machining parameters. The pulse duration has the greatest impact on the variation of the lateral working gap. Based on these findings, specific geometric design parameters and process parameter combinations for future process designs are derived to address the key challenge of process design, which arises from complex process mechanism.