Marcus Lartz¹, Dirk Haack¹, Frank Papa^2
1Tronic Concept, Düren, Germany
²GP Plasma, Tucson, AZ
A variety of parameters must be considered when developing coatings for forming tools. Those parameters are not only directly related to the coating process itself but also to initial surface preparation, such as heat treatment and polishing, as well as possible finishing preparations after a coating. The optimal parameters are all based on the unique wear and friction mechanisms at the surface of molds and dies in their specific application.
Over the last decades, mostly standard PVD coatings were used for molds and dies such as TiN, CrN, TiCN, AlTiN, AlTiCN and AlCrN. All of these coatings were not specifically designed for these kinds of applications or are intended as broad band solutions. Hence, Tronic Concept has developed tailored coatings and has moreover studied various parameters, such as the chemical composition, morphology, structure and thickness of applied coatings to fill this important gap in industrial research and development.
Processing high tensile sheet materials, hot forming applications, aluminum die casting or aluminum forming all require a dedicated coating design and surface treatment. To aim maximum performance, for each single application the coating properties, such as hot hardness, oxidation resistance and friction coefficient, need to be specially adjusted so that they correspond to the specific demands. One major conclusion of our studies is that the use of standard PVD is not sufficient to achieve all properties required by high end forming and molding applications. Newer technologies like DUPLEX-coatings and Hybrid-coatings are needed to fulfill today's challenging demands.