Role of a Computer Aided Analysis in the electropolishing processes

Electropolishing is the state-of-the-art surface finishing process for medical implants, such as metal vascular stents. The process removes burrs, heat affected zones and micro-cracks resulting from the pre-processing steps, providing excellent edge rounding and biocompatibility of the stent struts which minimizes the potential for lumen trauma. Nevertheless, the major challenge of the process is its effectiveness, which relies on a proper control of the current density distribution and electrolyte refreshment over the substrate. In case of a poorly controlled current density distribution and insufficient electrolyte flow refreshment near the electropolished surface, an unacceptable roughness, pitting or even surface burn may occur. Moreover, localized high current density areas will lead to an excessive local metal removal rate, thereby compromising the dimensional tolerances of the part.
A Computer Aided Analysis may serve in this case as fast and robust performance analysis of an electropolishing process. Such a feasibility analysis enables to obtain the current density and metal removal rate distributions over a treated component and therefore, an overview on the final quality of a product before running any physical process. In addition, an unparalleled insight into the process is gained, which includes a definition of the operating window of the process conditions that ensure attaining the target surface quality. The technology uses Finite Element Analysis to solve the distribution of the current density and calculates the metal layer removal rates from Faraday’s law. It is also used for further process optimization, which aim to achieve a higher quality of the electropolished surface.