Drillability Of Titanium 6246 From Chips Formation Perspective

Drillability is a term derived from machinability which is applied for drilling. This paper proposes another perspective of drilllability, i.e. form chips formation, a never observed previously for material of titanium alloy 6246. This study will broaden the basic knowledge about machinability of this material, which up to this time is barely available. Some parameters that believed to be affecting the drillability were varied: cutting speed, feed rate, depth of drilling, cooling application and heat treatment to the material prior to drilling. The Taguchi method was used for designing the experiments and analysis of variance was carried out to find out the effect of each of parameters towards drillabilty. Degree of segmentation is used to quantify easiness of chips to break. Analysis with Minitab shows that above mentioned parameters affecting the degree of segmentation by 20 %,8.4 %, 3.2 %, 5.8 %, 29.0% respectively. Heat treatments is the most affecting the chips segmentation degree which means different heat treatment might change the microstructure of the titanium blocks and their mechanical properties. Whereas, application of coolant only affecting the dillability by 5%. It indicates that the way of applying the coolant, i.e. external coolant type, is not an effective one.