Case studies on productivity improvement and supplier selection

Abstract

Two case studies have been reported (i) improvement of productivity in Electrical Discharge Machining (EDM) and (ii) Multi-Criteria Decision Making (MCDM) approach for supplier selection.Case study (i) highlights EDM of stainless steel in which best process environment (optimal) has been determined to satisfy productivity and quality requirements simultaneously. Material Removal Rate (MRR) during the process has been considered as productivity estimate with the aim to maximize it. Where as surface roughness i.e. (Ra value) of the machined surface has been chosen as surface quality estimate with the requirement to minimize it. These two contradicting requirements have been simultaneously satisfied by selecting an optimal process environment (optimal parameter setting). Desirability Function (DF) approach coupled with Taguchi method has been used to solve the problem.In case study (ii), usefulness of grey based MCDM approach method has been highlighted to solve multi-criteria decision making problem of supplier selection. The method has been found efficient to aggregate multiple attribute values into an equivalent single quality index (overall grey relation grade) which facilitates ranking/benchmarking as well as selection of the appropriate alternative supplier