Drilling analysis of cemented carbide drills after chemical treatment under low heating

Abstract

This work was carried out in the shop floor of a chemical filters manufacturer. These filters are typically used by petroleum and chemical industries. They are called mirrors and are made in thick carbon steel plates, on which the holes are held. Special drill with carbide inserts and internal channels for cutting fluid supply at the drill tip was used. The carbide inserts were coated with PVD multilayer based on AlCr. The mirror manufacturer was interested in improving its productivity. At the moment of this research, the company had already made several attempts to improve their productivity, especially searching for collaboration with machine tool manufacturers. Such attempts have resulted in the use of a kind of special drill that has come to be applied in this study. The main aim of this work was to propose a new procedure to reduce wear of cemented carbide drill inserts. This new procedure consists of applying on the cemented carbide inserts a lubricant called Militec followed by heating it at 80 °C for 30 min. This product is commonly used to lubricate motors and engines. The results showed that the use of the proposed new procedure was a promising way to protect inserts against the wear in the case of drilling process investigated in the present work. The support for this conclusion was based on the inserts wear reduction of about 37% when compared with the untreated inserts.