Parametric investigation on surface roughness and hole quality of Ti metal hybrid fibers cored laminate (MFL) during abrasive water jet drilling

High-strength environment-friendly metal-fiber laminates (MFLs) are increasingly used for primary structures for various engineering applications. The surface roughness variation and delamination factor of a titanium (Ti) metal-cored basalt/flax fiber laminate were investigated during abrasive water jet drilling (AWJD). The present AWJD investigation is to establish the correlation of four important process independent variables of WJP-water jet pressure, T-S-traverse speed, Q(MFR)-abrasive mass flow rate, and SOD-stand-off distance to the delamination factor (Fd-top) and surface roughness (R-a) of drilled hole. Central composite design (CCD) of L-29 orthogonal array was used to perform the experimental observations. The statistical approach (ANOVA) was employed to determine the contribution of individual AWJD parameters to drilling operation. It is identified from experimental results that the water jet pressure is the most predominant process parameter and its contribution on Fd-top and R-a were 74.28% and 72.48%, respectively. Increasing the water pressure from low (160 MPa) to its higher range (320 MPa) showed that the surface roughness and delamination factor were reduced irrespective of other drilling parameters. Increased water pressure provides enough kinetic energy for abrasive particles to facilitate a higher penetration potential during the drilling process. Scanning Electron Microscope (SEM) images show the machining-induced damages like ploughing marks, uncut fibers, ridges, craters, matrix smearing, and delamination on an abrasive water jet drilled surface of prepared MFL.