Investigation on Surface Roughness in Abrasive Water-Jet Machining by the Response Surface Method

Abstract

This paper focuses on optimizing process parameters in abrasive water-jet machining with the objective of minimizing surface roughness in brass-360. The following process parameters were considered: abrasive flow rate, pump pressure, stand-off distance, and feed rate. The experiments were conducted using a Taguchi L27 orthogonal array. Response surface methodology was used to decide the optimal process parameters that minimized the surface roughness. Analysis of variance reflects the relative significance of process parameters and is used to find contribution of factors. Furthermore, a mathematical model was developed to correlate the machining performance. It was found that the pump pressure was the most significant parameter affecting the surface roughness. The optimal combination of process parameters are an abrasive flow rate = 75.37 g/min, pump pressure = 399 MPa, stand-off distance = 1 mm, and feed rate = 557 m/min. Finally, using a desirability function method, the optimal parameters for minimizing surface roughness were determined. The machined surfaces were examined with field emission scanning electron microscope and an atomic force microscope to observe the quality of surface obtained with the optimal settings obtained through response surface method.