Controlled-Depth Milling of Isogrid Structures With AWJs

Abstract

An experimental investigation was conducted to determine the feasibility of using abrasive-waterjets (AWJs) for controlled-depth milling of aluminum and titanium isogrid parts used in aerospace and aircraft structures. The effects of a wide range of milling parameters were studied. It was found that the traverse rate is the most critical parameter that affects the uniformity of the milled surfaces. Traverse rates on the order of several meters per second were found necessary to control the milling depth accuracy to within 0.025 mm. The problem of dynamically controlling the AWJ process parameters was negated by using a maskant material over the workpiece. The mask was AWJ-cut with the required pattern to be milled. The general topography of the milled surface was found to be more dependent on process kinematic parameters than AWJ process parameters, while surface morphology was found to be highly dependent on abrasive parameters. Milling to thin skins of 0.5 mm was demonstrated.