Selective Laser Melting (SLM) is a powder bed based Additive Manufacturing (AM) process that is currently being established in the series production of Ti6Al4V components in the aviation industry. One advantage is the significantly lower Buy-to-Fly ratio. However, subsequent machining is necessary in order to remove support structures of the SLM process and to fulfill quality requirements. Experimental results on support structure removal and simultaneous finishing of holes by helical milling are presented. Engagement conditions in helical milling are strongly influenced by the support structure. Material removal rates in both peripheral and axial direction are calculated and agree well with the variation of measured forces in these directions. In addition, the surface roughness of the machined holes is affected by the support structure design and may change along the hole perimeter. The findings indicate how support structures should be designed in order to obtain high quality bore holes in one machining step.
