Effect of different parameters on surface roughness and material removal rate in abrasive water jet cutting of Nimonic C263

Abstract

Abrasive water jet cutting is the recent non-conventional and useful processes because of its characteristic advantages. The influence of jet pressure, standoff distance and cutting Speed on surface roughness, material removal rate during abrasive waterjet cutting of Nimonic C263 super alloy has been analyzed in this paper. The roughness of the surface was evaluated in four phases along the width to know the distinct texture of the surface. The rate of material removal was also measured during experiment. The experimental results showed that the roughness of the bottom surface was extremely affected by standoff distance and pressure of jet. The rate of material removal was also noticed to be dependent upon the cutting parameters.

Introduction

The machining of high strength alloys, all brittle and hard to cut material can be performed effectively by abrasive water jet machine. This cutting method is more efficient compare to other machining process as it has lots of advantages like no heat effected zone, good surface finish, high flexibility [1]. In this cutting process, elevated pressure water jet strike the material by giving the momentum to the abrasive particle at mixing chamber. The material removal mechanism by Abrasive water jet cutting (AWJC) depends on the type of work piece material [2]. In case of brittle material, material removed by micro-cracking and inter-granular fracture at low impact angle [3]. Zeng et al. [4] noticed that a wave of stress produced by impact of high pressure jet causes fracture. They also observed that erosion rate is extremely correlated with grain size and fracture strength of work material. The material removes in case of ductile material by abrasive wear and plastic deformation. The micro-cracking happens at the top kerf and plastic deformation occurs at the bottom of the kerf [5]. It is applicable to many field by using many operations like peening [6], turning [7], forming etc. Many researchers analysed different parameters to optimise better machining properties. Selvan et al. [8] investigated the impact of multiple process parameters on depth of cut and surface quality after cutting of Kevlar-phenolic composites. They concluded that elevated jet pressure and increasing mass flow rate is preferential as it raises depth of cut and reduces surface roughness. But high traverse speeds reduces depth of cut and also reduce surface quality. Hreha et al. [9] attempted to determine the cause of vibration and acoustic emission during cutting and the correlation of surface texture with these. The influence of nozzle diameter, standoff distance and cutting velocity on average kerf width and surface roughness was optimized through regression model during abrasive waterjet cutting of TRIP-steel sheet [10]. Aich et al. [11] optimised effect of different machining parameters on depth of cut during abrasive waterjet cutting of borosilicate glass. It has been reported that the diamond abrasive produce high extremely erosion rate and surface quality during cutting of polycrystalline diamond [12]. The type of abrasive is also responsible for cutting quality. The garnet produce higher taper of cut compare to silicon carbide and aluminium oxides. The width of cut increase in case of SiC as it possess high hardness [13].The cut surface was also analyzed to identify the striation formation and variation of surface texture from top to bottom of the thickness [14], [15]. Various studies has been performed to investigate the surface pattern, surface quality in different materials but it is first time with a super alloy. In this investigation, the impact of distinct parameters on surface roughness and MRR has been studied and different surface pattern throughout the thickness has been determined.