Diamond burnishing for mould and die industry

Special ultra-precision processes are necessary to machine surfaces for optical applications with required surface roughness Ra < 30 nm. The use of ultra-precision cutting results in low feed f and significantly reduced cost-efficiency. Diamond burnishing can be a cost-effective alternative. The process reduces the surfaces roughness and generates residual stress, which is advantageous for the workpiece's fatigue strength. However, diamond burnishing is mostly used for post-processing of rotating parts. Applications of diamond burnishing by linear motion, e. g. in mould and die making, are not common. The article shows first investigations to manufacture surfaces with optical quality on milled parts made of steel X37CrMoV5-1, copper CW008A, brass CW612N and aluminium 5083. The experiments were carried out on a 5-axis milling machine tool PFM 4024-5D, PRIMACON GMBH, PeiÃenberg, Germany. The feed velocity, the penetration depth, and the stepover were varied as input para meters. Vickers hardness and the surfaces roughness were measured as reference criteria. Thus, the ability for the surface improvement by diamond burnishing of complex shaped surfaces could be shown.