Optimisation of surface finish in abrasive water jet cutting of Kevlar composites using hybrid Taguchi and response surface method

Abrasive water jet cutting (AWJC) is particularly useful for difficult-to-cut materials like composites, super alloys and ceramics. However, the surface finish produced is often poor, necessitating finishing operations like grinding, etc., which lead to delamination in case of polymer composite laminates. Therefore, optimum selection of process parameters is important in AWJC. This paper presents the influence of three process parameters (water jet pressure, abrasive flow rate and quality level) on surface roughness (Ra) in AWJC of Kevlar composites. The optimal parameter setting was determined using a hybrid Taguchi and response surface method (HTRSM). The experimental results and ANOVA analysis indicate that quality level and water jet pressure have more significant effect on Ra. A second order response surface model was developed using the central composite rotatable design CCRD). Finally, confirmation experiments were conducted to verify the predicted and experimental results at optimal settings, and an excellent agreement was obtained between the two. © 2008, Inderscience Publishers.