INVESTIGATION OF SURFACE CHARACTERISTICS IN PRECISION HOLE MACHINING OF INCONEL-625 USING ABRASIVE AQUA JET DRILLING

Abstract

Inconel-625 is a high-performance nickel-based superalloy which offers exceptional properties such as extensive resistance to corrosion, high strength-to-weight ratio, hardness, and impressive heat tolerance. Machining precise holes with required dimensional accuracy is challenging in Inconel-625 using conventional drilling processes. The investigation aims to improve the quality characteristics of hole machined on Inconel-625 by using the abrasive aqua jet drilling (AAJD) process. The influence of jet pressure ([Formula: see text]), table feed ([Formula: see text]), mass flow rate ([Formula: see text]) and gap distance ([Formula: see text]) on the erosion rate ([Formula: see text]), surface roughness ([Formula: see text]), circularity error (CI[Formula: see text]) and striation zone ([Formula: see text]) are investigated. The weighted principal component analysis (WPCA)-based response surface methodology (WPC-RSM) is employed to analyze and optimize process parameters. The optimal parameter settings ([Formula: see text] -300 MPa, [Formula: see text]-1.5 mm, [Formula: see text]-64 mm/min, [Formula: see text]-0.55 kg/min) are observed to produce substantial improvement in response. Comparing initial and optimal conditions, the surface roughness ([Formula: see text]) is decreased by 10.15% from 3.25 [Formula: see text]m to 2.92 [Formula: see text]m. The CI[Formula: see text] and [Formula: see text] are also reduced by 38.02% and 12.74%, respectively. The erosion rate ([Formula: see text]) is improved by 8.79% with the optimal settings. [Formula: see text] is found to be the most influential parameter, followed by [Formula: see text]. Scanning electron microscopy (SEM) pictures and 3D roughness plots are used in the surface topography analysis.