Electropolishing of the 3D printed parts: from trial-to-error towards right-first-time

Polishing of 3D printed parts is considered as extremely challenging. First, 3D printing might start from the CAD of a lighter weight part version that replaces an already existing model. This inevitably also means that the geometry of this new part will be more complex than the original one. Second, 3D printing opens the possibility for producing several variations of a machined base part, whenever a further diversification makes sense from a functional point of view. Third, parts are designed and 3D printed for novel applications, beyond the capabilities of traditional machining. Hence in general, it can be stated that 3D printing is responsible for two main evolutions: the production of parts with higher geometrical complexity, and the production of a wider variety of parts. Adding for the fact that 3D printed metal parts have an extremely high surface roughness, it is clear that the need and challenges for Computer Aided Engineering (CAE)based surface finishing become considerably higher when compared to traditionally manufactured parts.

Several polishing techniques can be applied to these 3D printed parts, e.g. tribo-finishing, chemical polishing, plasma-electropolishing, and traditional electropolishing. Taking into account process performance and cost parameters, it is clear that the combination of an electrochemical polishing method, followed by a final tribo-finishing step, is a prime candidate for polishing 3D printed parts in a very fast and cost-effective manner, down to final roughness and dimensional specifications. Nevertheless, a use of CAE is crucial here.