Análise da influência de revestimentos aplicados por PVD na vida útil de brocas canhão e helicoidais de metal duro em processo de furação de ferro fundido e alumínio em condições reais de processo

Abstract

Cutting tools are made of materials able to withstand high temperatures and high mechanical loads and, because of that, their prices are elevated. In order to increase their lifetime without increasing their costs significantly, coatings with better mechanical characteristics than the base materials are generally used. The aim of the present work is to compare the lifetime of stepped twist drills and gun drills with and without PVD coatings in the drilling process of AA C355 aluminum alloy and SAE G3000 gray cast iron in real machining process conditions. After the tests, it was possible to determine the most economical choice considering the tested coatings. In the case of gray cast iron, which is machined using the stepped twist drill, the results showed that the Firex coating increased the tool life in 67%, while Pertura and Alcrona coatings yielded 65% and 6% life increase, respectively. In terms of costs, Firex coating has lower cost than Pertura, being the most economical choice in this case. Considering the gun drills used to machine aluminum, the Balinit C coating improved the tool life in 95%, leading to significant savings when compared to the uncoated drill.