Influence of Roughness on Conoscopic Holography Digitizing of DIN34CrMo4 Surfaces

Conoscopic Holography is a non-contact digitizing technique used in inspection and reverse engineering tasks. A laser beam is projected onto a surface, and its reflection generates a holographic pattern inside the sensor. This pattern is later analysed and the distance between sensor and surface is calculated. Like other optical techniques, conoscopic holography shall be affected by surface properties and ambient conditions. This works deals with the influence of surface roughness and manufacturing process on the quality of digitizing. 34CrMo4 steel test specimens have been manufactured to obtain four different Ra levels. Two different manufacturing process, electrical discharge machining (EDM) and ball-end milling (BEM) have been also considered. Quality of the digitized point clouds under different sensor configurations has been analysed, in order to provide a recommendation for optimal capture conditions.