Prominence in Understanding the Position of Drill Tool Using Acoustic Emission Signals During Drilling of CFRP/Ti6Al4V Stacks

Abstract

CFRP/Ti6Al4V stacks are widely used in aerospace and automobile industries as structural components. The parts are made to near net shape and are assembled together. Aerospace standards demand rigid tolerance for the holes. While drilling stacks, during the exit of drill from CFRP and entry into Ti6Al4V, there is a change in the overall behavior of the drilling process due to changes in the mechanical properties of the two materials. Hence, stacks should be drilled under their optimal machining conditions in order to achieve better hole quality. The machining parameters and tool geometry are different for CFRP and Ti6Al4V. This requires knowing the thickness of the CFRP and Ti6Al4V layers beforehand so that at the time of drill tool transition from CFRP to Ti6Al4V the machining parameters can be altered. But in aircraft bodies the cross-section varies along the profile and the thickness of the individual layers at different locations. The current study proposes the use of acoustic emission (AE) signals to monitor the drill position while drilling of CFRP/Ti6Al4V stacks.

Towards Material-Batch-Aware Tool Condition Monitoring

“…It is shown that there are several material identification approaches researched in subtractive manufacturing, which aim at identifying various major materials, material sub-classes, specific materials, material grades, and material batches. While there are several approaches for identifying different materials during machining, such as aluminum and steel [13][14][15], aluminum and carbon-fiber-reinforced plastics (CFRP) [16,17], titanium and CFRP [18,19], and steel and ceramic [20], there are only a few approaches investigating batch-specific material identification [10,21].…”