Abstract
Efforts have been made to determine the optimum machining parameters for 4340 steel, which is commonly used in the aerospace industry, in order to reduce the cutting tool wear, energy consumption of the process, and average surface roughness (Ra). For this investigation, nanoparticles of Halloysite Clay Nanotubes (HNTs) were introduced into a synthetic lubricant and then dispersed via ultrasonication. To understand the effects of the HNTs on the lubricant, tests were performed on a four-ball T-02 tribotester following the ASTM D 4172 standard. The wear scar diameters (WSD) were measured through optical microscopy. It was shown that optimal nanoparticle concentrations were between 0.1 and 0.2 wt.%. A Computer Numerical Control (CNC) lathe machine was employed varying spindle speed (rpm), depth (in), feed rate (in/tooth), and HNT concentration at three different levels, according to Box Behnken experimental design. Plates of an AISI 4340 steel were machined using the combinations obtained by this method. Tool edge loss of cutting inserts, surface roughness (Ra), and energy consumption were recorded after each test. The results obtained with this method show that machining processes can be optimized in order to reduce cost productions in CNC lathe machining processes using Halloysite Clay Nanotubes (HNTs) as an additive for synthetic lubricant.