Post-Coating Treatment of Cutting Edge for Drilling Carbon Fibre Reinforced Plastics (CFRP)

Drilling of highly abrasive carbon fibre reinforced plastics (CFRP) requires carbide tools with geometrical highly adaptable tool geometries and wear resistant diamond coatings. To counteract the tradeoff between long tool lifetime by preferably thick diamond layers leading to large cutting edge radii (bluntness), and the sharpest possible cutting edge to generate flawless machining qualities, the following post-coating cutting edge treatment methods are compared: Laser-ablation and selective sandblasting. It is shown that laser treatment generates cutting edge radii of 3-4 μm leading to outstanding bore exit qualities in CFRP from the first bore on, while diamond still protects the rake face.