Performance evaluation of coolant concentration when end milling hardened steel using coated carbide tool

Cutting fluids having a significant role in machining operation and have a great positive impact, especially on the tool life, tool wear and surface roughness of the workpiece. Investigation on end milling of hardened steel AISI 1045 using coated solid carbide cutting tool under different coolant conditions was carried out experimentally. Experimented work involved three different coolant concentrations which are 3%, 6%, and 9%, with a different cutting speed of 35m/min and 50m/min. The depth of cut and feed rate was kept constant at 4mm and 0.05mm/tooth, respectively. The machining performance was evaluated based on the effect of tool wear, tool life and surface roughness. Analysis of recorded data shows that tool performance during machining is dependent on coolant concentration and cutting speed. Coolant with 3% concentration gave the best overall performance as an effective combination of cooling and lubrication functions during machining. Longer tool life when machining at cutting at a higher cutting speed of 50mm/min, due to the reduced amount of the build-up edge (BUE) on the cutting tool.