Development of process specifications for improving the surface finish in the steel grinding operation

An aviation firm was facing the problem of 40-50% rework in the components made from nitriding steel. A high grade of surface finish (0.1 mum max.) is required for the mating parts to prevent early wear of the part. A study on 6 machining parameter was conducted using the statistical design of experiment technique. Study helped in determining the optimum process specifications. The results of the confirmatory trial show a consistent high performance centred around .05 mum against the previous performance of 0.2-0.25 mum. A fractional factorial experiment using the orthogonal array layout developed by Taguchi has helped in establishing the robust process conditions for improving the surface finish of precise mating components. 40-50% of costly rework is eliminated, delay in delivery of components to the assembly line is avoided. The firm saves one million rupees per annum as a result of total elimination of rework.