Economic micro forming using DLC- and TiN-coated tools

Abstract

In the micro forming the application of lubricants complicate the cleaning of work pieces after micro forming, which due to small dimensions is more complex than in the macro range. Moreover, saving of lubricants might help limiting harmful effects on the environment and establishing healthier working conditions. However, the thin work piece material in micro forming usually has a lower maximum elongation compared to thicker materials in macro forming, which leads to a more sensitive dependence of the forming limit on the friction between work piece and forming tools. Therefore, it is highly desirable to precisely control friction conditions as well as reduce or even avoid the use of lubricants in micro forming. Possibilities to enable lubricant-free forming include various coatings of forming tools. In this work, the possible field of application of DLC-coated, TiN-coated as well as of uncoated tools from a tool steel (Germany standard 1.2379) were characterized in micro deep drawing. It was concluded that the DLC- and TiN-coating both show a significant advantage in lubricant-free micro deep drawing compared to a standard tool steel tool, and thus have a great application potential in micro forming.