CNC-assisted selective melting for improved surface finish of FDM parts

A novel CNC-assisted post-finishing tool, namely selective melting (SM) is designed and developed for finishing of fused deposition modelling (FDM) built parts. In this process, unlike the conventional post-finishing processes, materials in the form of chips are removed to reduce peak to valley height. The SM tool adds semi-solidified material to the neighbouring valleys to reduce the peak to valley heights. The present work provides an alternative to overcome the limitations of the poor surface finish of FDM built parts, and issues like location error effect, inner defect, minimisation of scallops and irregular pattern formation during post-finishing operation. In this research, theoretical and semi-empirical models have been developed for the prediction of surface roughness of a part before and after the SM process. The validation results showed that the developed approach played a significant role in improving the surface finish conditions of FDM built parts.