Evaluation of Hole Geometry and Damage Mechanisms in Abrasive Water Jet Machining of Flax Fiber Reinforced Epoxy Composites

ABSTRACT This study focused on the abrasive water jet machining (AWJM) behavior of the flax fiber reinforced epoxy (F/Ep) composites with an objective to minimize the geometric quality characteristics such as surface roughness ( R _a ), roundness, kerf angle, and cylindricity properties of the drilled hole. AWJM parameters considered for the present investigation were standoff distance (SOD; 1.5, 2.5, and 3.5 mm), jet pressure (120, 180, and 240 MPa), and abrasive flow rate (1.0, 2.0, and 3.0 g/s). Moreover, parameters' combinatory effect on the hole characteristics in the F/Ep composites was analyzed by employing response surface methodology (RSM) approach. Results clearly showed the jet pressure and abrasive flow rate and their interactions showed a more dominant effect on the geometric deviation of the machined hole. Furthermore, for reducing the surface roughness and kerf angle of the hole, machining at lower SOD of 1.5 mm with a lower jet pressure of 120 MPa was recommended. The developed quadratic regression models of response characteristics showed better accuracy with R ² value closer to 0.9995. Validation of the models was found to be satisfactory as predicted and experimental results were in good agreement with each other, clearly suggesting the predictability of the models. Field emission scanning electron microscopy (FESEM) images were captured to explore the surface morphology of the machined holes.