Hard cutting of pre-hardened plastic mould steels

Steel used in the manufacture of Plastic moulding tools require high hardness for a satisfactory life cycle. Moulds and Dies are manufactured by roughing, heat treatment, finishing and polishing. Pre-hardened steels need no further heat treatment and enable a shorter production time with lower manufacturing costs. The costs are mainly controlled by material and machining. Results of milling (roughing and finishing), threading and drilling tests of a corrosion resistant plastic mould steel with a chromium content of 14% at four different hardened states (30 to 45HRC) were determined and compared. Furthermore, the optimum hardening state for cost effective hard machining in mould and die making will be presented. The results of these investigations are shown on an appropriate high speed machining sample part.