Quality management for sustainable manufacturing: Moving from number to impact of defects

Number of defects is a simple way to determine the quality of a product. Quality of a process can also be determined on the basis of number of defects being produced by the process. This paper is an attempt to shift the focus from number of defects to the severity of defects. This also unlocks important concept of integration of sustainability with quality management (QM). QM is one of the areas of research which is equally dependent on quantitative and qualitative measures. As far as quantitative measures are concerned, Six Sigma is the most used metric to define the quality of a system. The 'Sigma' is a measure based only on the number of defects which does not involve severity of impact due to defect. Existing literature about sustainability from Six Sigma takes ecological foot print as a defect. Authors argue that different types of defects may result in different level of impact and consequently affect the sustainability of the system under investigation. In this paper, authors are discriminating defects on the basis of severity of their end impacts. Allocation of appropriate weight to each defect develops a new framework of Sigma metric in statistical quality control (SQC). This framework is able to capture economic, environmental, and social impact of defect. It is expected that practitioners and academicians will find using this new sigma metric to be suitable for sustainable manufacturing. This paper also presents an industrial case study as an evidence of achieving higher sustainability for competitiveness by classifying defects on the basis of their end impact. (C) 2019 Elsevier Ltd. All rights reserved.