Experimental Investigation of Abrasive Waterjet Machining of Titanium Graphite Laminates

Abstract

High temperature Fiber Metal Laminate – Titanium/Graphite (Ti/Gr) is an advanced material system, developed to meet the high temperature requirements in aerospace applications. High specific strength and stiffness of composite core along with its protection from aggressive environment by tough titanium alloy sheets qualify FMLs for a promising alternative material where metallic and composites overcome each other’s limitations. However, industrial employability of this three phase system is often limited by the machining challenges posed by the difference in material removal mechanisms of Titanium alloy, PIXA thermoplastic polyimide resin and graphite fibers. An experimental investigation was conducted to evaluate the machinability of 1 mm thick Ti/Gr laminate sheets through Abrasive Waterjet (AWJ) machining process in terms of kerf characteristics and material removal rate. The parametric influence of AWJ operating variables on machining performance was studied by systematically measuring operating variables (traverse speed and Abrasive flow rate) using fully crossed Design of experiment (DOE) scheme, and statistically analyzing using ANOVA (Analysis of variance) technique. Empirical models were developed to quantify these effects and predict the influence of process parameters on material removal rate, kerf taper, entry damage width and overcut in straight cutting of Ti/Gr sheets.