High-speed milling of tool steel dies for aluminium extrusion: Surface roughness, dimensional tolerance and chip removal mechanisms

Die finishing has a fundamental importance to ensure a good quality of aluminium extruded parts and involves important economic effects due to the vastness of metalworking industry and the relatively short tool life in this field. Maximum machining efficiency is thus crucial. The research addresses optimization of finishing performances on tool steel extrusion dies. Milling tests are carried out on semimanufactured parts to ensure adherence to standard industrial technological chain, varying cutting parameters towards the field of high-speed machining (HSM). Dimensional tolerance is determined on die lands. Land surface roughness is measured through a multiscale approach and modelled as a function of cutting speed and feed. The above methodology enables a correlation between macroscopic process outcomes and chip removal mechanisms in the microscale.