Step over (Ae) effect on cutting parameters when trochoidal pocket milling of titanium alloy ti-6al-4v

Abstract

Titanium alloy is highly demanding in the aerospace industry due to its unique properties such are high strength-to-weight ratio and high thermal conductivity thus, made the material widely used in aerospace industries and excellent in its applications. However, those criteria’s become a crucial issue for machinists as titanium is categorized as difficult-to-machined material. High thermal conductivity caused shorten tool life because of the heat generated during machining was transferred directly to the cutting tool and leads to rapid tool wear. This experiment was conducted using 3 axis CNC Milling machine under wet cutting conditions. In order to identify the effect of step over, cutting speed and feed rate were fixed at constant values while step over (ae) values were varieties. The effect investigated were tool wear, wear mechanisms and tool failure modes. Tools experienced a longer tool life at low cutting speed of 60m/min, while chipping and notch wear appeared at high cutting speed 90m/min. The increasing of the step over value give less than 10% of the wear and reduced only 15% of machining time. With this, trochoidal milling proved that the step over give a minor contribution to wear while the dominant contribution was cutting speed followed by feed rate where the wear rate increased as the cutting speed increased.