Optimization of process parameters for machining defects of glass fibre reinforced polymer composite machined by AWJM

Abstract

For the machining of composites like glass fibre reinforced polymers (GFRP), abrasive water jet machining (AWJM) is generally used. AWJM has proven to be a cost-effective and efficient metal removal process of composites, in which a high-speed jet of abrasive and water strikes on workpiece surface to erode the material. In this paper, an experimental investigation is described which is focused on investigating the effect of process parameters on defects like delamination, pulling out of fibres and embedment of abrasive particles of machined samples during AWJM of GFRP composites. For design of experiments response surface methodology (RSM) based on the central composite design (CCD) approach is used. Water pressure (WP), traverse rate (TR), stand-off distance (SOD) and abrasive mass flow rate (AMFR) are considered to study their influence on delamination. The scanning electron microscope (SEM) is used to investigate the microscopic features of machined surfaces. It is revealed that delamination decreases with an increase in AMFR, with a decrease in TR, Further, optimization based on the desirability function is also performed to minimize the delamination. The optimal combination of the cutting parameters (SOD = 2.6 mm, WP = 175-MPa, TR = 104 mm/min and AMFR = 582 g/min) gives the optimized values of Max. DLL is 0.299 mm.