Evolution of process capability in a manufacturing process

Abstract

Before mass production of individual components industries may assess its capability to produce it according to specifications. This capability assessment is a common requirement in the automotive sector. This work shows a case study, providing an in-depth analysis, on a critical component and finds evidence of process degradation over two years of production, quantified through capability analysis. At pre-production, it was concluded that the process was capable and, thus, no statistical process control was done during its production. Over the months no defective units were detected but then its level began to increase and it was apparent that process variability had increased and the process was no longer capable. Process improvement activities were developed using known quality tools and methodologies. This work shows how the control plan initially defined became obsolete and discusses the need to periodically review quality control mechanisms.