CVD diamond-coated steel inserts for thermoplastic mould tools—Characterization and preliminary performance evaluation

The increasing demand for quality on moulded polymer parts is stressing the research and development on new and enhanced injection moulding materials and tools. The latter, is the objective of the study reported here focusing the research on moulds with considerable lower adhesion walls and simultaneously better mould heat extraction rates. Polycrystalline diamond coatings enable the attainment of both characteristics above highlighted, inferring to the mould wall a higher thermal conductivity coefficient and one of the lowest friction coefficients. Recent developments in the diamond chemical vapour deposition (CVD) process, combined with the usage of appropriated interlayer systems, open the possibility to apply polycrystalline diamond coatings onto steel mould inserts. Therefore, this study reports results obtained on the properties of diamond thin films deposited on typical mould steel, and preliminary results on the interaction between the diamond/steel system and the melt polymer.