Influence of Cutting Parameters on Exit-Side Defects in Abrasive Waterjet Machining of UNS A92024 Aluminum Alloy

Abstract

Abrasive waterjet machining (AWJM) is widely used for cutting aerospace aluminum alloys, but exit-side defects associated with jet lag can degrade surface integrity and dimensional accuracy. This work investigates the influence of water pressure, abrasive mass flow rate, and traverse feed rate on the formation of jet-lag defects at the exit side of cuts in UNS A92024 aluminum alloy plates of 10 mm thickness. A full factorial 33 experimental design was implemented to manufacture 27 square samples (20 × 20 mm), which were subsequently characterized by optical microscopy at 20× magnification. The semicircular jet-lag defects were quantified using Imaging processing techniques to determine their projected area, and the resulting data were analyzed with multifactor ANOVA and multiple linear regression. The results show that traverse feed rate and water pressure have a statistically significant effect on defect area, with traverse feed rate being the most influential factor, whereas the abrasive mass flow rate plays a secondary role within the investigated range. Combinations of high water pressure and low traverse feed rate led to cleaner cuts with reduced exit-side damage, and contour plots allowed the identification of operational windows that minimize defect formation. The proposed methodology provides a systematic framework for characterizing jet-lag defects in AWJM and can be extended to other alloys, thicknesses, and advanced characterization techniques to support process optimization in industrial applications.