Multi-Objective Optimization in Traverse Cut Cylindrical Grinding

Abstract

Present work aims to study the effects of grinding parameters on surface roughness (Ra and Rq) in traverse cut cylindrical grinding process, while grinding of stainless steel. Experiments have been conducted as per L9 orthogonal array of Taguchi method. Grey based Taguchi method has been used to optimize the grinding parameters to minimize surface roughness parameters Ra and Rq simultaneously. The analysis of signal to noise ratio has been applied to investigate the effects of grinding parameters and optimize them. From the results of this study, longitudinal feed is identified as the most influential grinding parameter on surface roughness. The optimization methodology used in the present study of cylindrical grinding process is very useful to determine the optimum grinding parameters for minimum surface roughness. In the manufacturing industry, surface finish of any machined product is very important to determine the product’s quality, in so far as cylindrical jobs are concerned, it is obviously true as well. Cylindrical grinding is one of the important manufacturing processes, used for producing accurate and good surface finish cylindrical rods. Obtaining the better surface finish jobs in cylindrical grinding is mainly depends on correct selection of grinding parameters. Optimum parameter selection is difficult task in cylindrical grinding process because of its complexity while solving it. But, through systematic optimization methodology like design of experiments (DoE), it is possible to select optimum parametric combination. The present work is an attempt to optimize grinding parameters to minimize surface finish by using DoE’s Taguchi method. Good surface finish is demanded in many engineering and domestic applications, because, it is an important aspect of tolerance of finished part; it minimizes friction and wear, thereby enhancing operating hours of the components. The arithmetic average height parameter (Ra) is an important roughness parameter, which most universally accepted and used roughness parameter to describe the quality of machined part. Review of available literature shows that Ra has been focus of most of the studies, but, Ra parameter alonely can’t provide full description of surface. Root mean square roughness (Rq) is also an important parameter used to specify quality of the machined part. It is more sensitive than Ra. If the number of roughness parameters used is increased, full description of the surface profile can be obtained [1]. The present study aims at consideration of two roughness parameters Ra and Rq simultaneously for the surface roughness generated in cylindrical grinding operation. Extensive literature survey has been made on optimization of process parameters in different machining operations for single objective optimization problem using Taguchi method [2] and multi objective optimization by using Taguchi method combined with grey relation analysis [3, 4]. Some of the previous studies are included here, Taguchi methodology’s tools such as the orthogonal array, signal to noise ratio, factor effect analysis and analysis of variance were used to analyze and optimize the process parameters such as speed, feed, infeed and mode of dressing in surface grinding[5]. Similar technique was used in CNC milling operation to optimize the surface roughness, this study considers feed rate, spindle speed and depth of cut as control factors, operating chamber temperature as noise factor and the usage of different tool inserts in the same specification, which introduced tool condition and dimensional variability. Finally, significant factors on surface roughness were found by using analysis of variance and optimal cutting combination determined by seeking the best surface roughness [6]. Reference [7] used application of Taguchi method, analysis of variance for minimization of delamination influenced by drilling parameters and drill point