Analysis of surface roughness for parts formed by computer numerical controlled incremental forming

Surface roughness tests were performed on computer numerical controlled (CNC) incrementally formed sheet metal parts using various tool depth increments and spindle speeds. A non-contact method using white light interferometry was selected to avoid scratching the material surface. All parts were formed from annealed Al 3003 sheet to a shape with a flat 45 8 wall section for testing. A relationship was defined between peakto-valley roughness and depth increment, which was then compared to theory for shear forming. The surface quality of modern incremental methods and shear forming was shown to depend on similar settings, and the defined relationship allows for knowledgeable control of surface roughness in future work on such applications as reflective surfaces.