Deposition of nanoscopically smooth DLC tool coatings for dry forming of aluminum sheets

Recent investigations demonstrated the applicability of diamond-like carbon (DLC)-coated tools for dry forming of aluminum, which is a challenging application field due to the high adhesion tendency of aluminum. An exceptionally low roughness of the coated forming tool is required to prevent adhesion-induced tool failure. To establish dry forming of aluminum in industrial production processes, efficient methods must be developed to manufacture DLC-coated forming tools with reproducible high surface quality. This paper illustrates two DLC coating processes that are especially optimized for deposition of nanoscopically smooth DLC tool coatings. Two optimized coating systems were deposited, characterized, and subsequently evaluated using application-oriented strip drawing tests to validate their performance in comparison with a state-of-the-art coating system. One coating process showed high potential for production of DLC-coated forming tools with the required surface quality.