Investigation on chip morphology and properties in drilling aluminum and titanium stack with double cone drill

Abstract

The next generation aircraft industry looks upon the multi-layered material structures. In this research work, conventional drilling technique is incorporated in assembly process for the stack material. However, in drilling process, chips play a significant role for chip tool life but the chip breaking mechanism is still unsolved, the key challenge of making high-quality hole and hole surface integrity for hole making of multi-layered material. To illustrate this issue, a series of drilling experiments were conducted on Al/Al stacks and Al/Ti Stacks with double cone drill. The objective was to examine the effect of process parameter, and influences of the double cone drill bit geometry on output response such as chip formation and chip breaking mechanism were investigated. Then, the effect of gap between Al/Al stacks and Al/Ti stacks materials respective chip formation as they flow away was probed. Surface roughness was measured by non-contact-type 3D laser scan microscope system. It was observed from the experiment that surface roughness value decreases from 4.06 to 2.59 μm with increasing cutting feed. The scanning electron microscope (SEM) analysis was carried out to study the chip morphology. Results demonstrated that upper-layer surface integrity can be improved by selecting suitable tool angles and process parameters.