Christoph Schiffers¹, Jeffrey Barlow², Ryan Lake^2
1CemeCon AG; Würselen, Germany
²CemeCon Inc., Horseheads, NY
Lowering the take-off weight for improved fuel efficiency is a key requirement for all aircraft. Carbon fiber reinforced plastic and materials with titanium/CRFP/aluminum stacks account for 50% of the weight of an aircraft today. Such materials are extremely abrasive and cutting tools must be protected by a diamond coating for drilling the tens of thousands of rivet holes and shaping panels with routers.
The aircraft industry sets very demanding requirements towards the machining tolerances and the surface quality. The hot-filament CVD technology is best suited to provide homogeneous diamond films for 3D objects like complex drilling, milling, and routing tools with multiple flutes. Depositing a diamond coating with nearly 10.000 Hv hardness in a high-volume industrial coater is one thing, interlocking the film with the cemented carbide is a technological challenge. CemeCon is mastering this with a deep understanding of the interaction between the diamond coating and the elements of different carbide grades. Proven recipes for the mechanical and chemical processing of the substrate ensure optimal adhesion of diamond coatings for more than 80 different carbides.
Twenty years of production experience have led to diamond films with a very smooth surface. The AeroSpeed^® technology is based on a novel preprocessing of the carbide and a diamond deposition process which is designed for very fine crystals and a smooth, homogeneous surface. Such smooth diamond coatings pave the way for drilling rivet holes with narrow tolerances and high consistency over the full tool life. Use cases underline the effectiveness of the concept of smooth diamond coatings for machining aircraft materials.
Direct milling of dental implants from ZrO2 blanks has the potential of becoming another very successful market for diamond coatings in addition to graphite machining and the aircraft industry.