Achim Boos (right), head of toolmaking at Ernst, and Robert Karle from Oerlikon Balzers inspect the drawing ring and shaped housing.
Oerlikon Balzers
Supplier Ernst produces around 25,000 special housings for dual clutch transmissions per month. The parts are formed with the drawing ring of a transfer tool. A smooth production process must always be ensured to meet the automotive industry’s high quality demands. The reliability of this process is made possible only using coatings and lubricants. The extremely high tool loads would otherwise lead to abrasive wear and damage in the drawing ring, which, in turn, would lead to grooves in the component and hence to rejects.
A TiCN standard coating was therefore used initially when developing the tool. High performance coatings are, however, necessary to maintain stringent delivery times for larger quantities and increase service life, as well as reduce set-up times and costs. The CrAlN-based Balinit Formera coating has been specially developed for high strength steels and demanding applications in metal forming. This coating should resist modern, high strength steels and also provide excellent abrasive wear protection with high coating adhesion and microhardness. Compared to CVD coatings, it provides a micrometre-thick layer and allows high dimensional accuracy.
First experiences confirm expectations: Balinit Formera's service life outperformed TiCN coating's by four to five times. "The potential for more is clearly there. This coating is a promising candidate for similarly demanding applications", believes Achim Boos, head of toolmaking at Zusenhofen, Germany. There could soon be an opportunity: by 2019, Ernst intends to invest more than 30 million euros at its site in Oberkirch, Germany, alone, mainly by expanding production. At the end of 2017, a new building is scheduled to begin construction. In this building, presses with 1,600 tonnes of compressive power should also be in operation, pushing the limits.