Micro-abrasive Waterjet Trepanning in Al6061-T6 Alloy: An Experimental Investigation

Abstract

AbstractIn high-value industries (aerospace, automobile, defense, etc.), various applications like assembly, engine cylinder bores, etc., require hole making with target size/shape, tolerances, and surface quality. The present study investigates the potential of the micro-AWJs (df = ~300 µm) in trepanning holes by considering Aluminum 6061-T6 alloy, as a case study. However, the stochastic, non-deterministic, and flexible nature of the AWJs result in holes with deviated form and dimensional characteristics that lead to part rejection. As the waterjet pressure (P) is the most significant parameter in dictating jet energy, material removal, and productivity, trepanning studies were carried out to investigate the waterjet pressure’s influence on the hole form, dimensional, and surface characteristics. Furthermore, the effect of P on productivity measures in terms of material removal rate (MRR) is investigated. From the results, the edge radius of the hole at the entry plane improved with a higher P by 30.19%. With the increase in the P, the hole diameter deviation from the nominal diameter and circularity error decreased by 10 and 58.88% at the top plane and 11 and 65.2% at the bottom plane. Cylindricity error and taper angle decreased by 11.84 and 15.23% at higher P. Uncut material size and burr length at the exit plane decreased by 43.48 and 24.77% at higher P and the MRR increased by 52.71%. Surface morphology was studied concerning the pressure, with the increases in the jet pressure surface roughness improves, and waviness increases. Micrographs were taken with the help of HRSEM to analyze the effect of P on material removal mechanism, it is observed that at lower P abrasive embedment is a visible phenomenon.KeywordsMicro-waterjetTrepanningDuctile materialEdge radiusCylindricityCircularity