インダストリアルエンジニアリングとマネジメント

Optimization in MIG Welding by Using Six Sigma Tools

Abstract

Muhammad Mudassar Sharif, Zahid Anwar, Yousaf Ayub, Amar Abbas and Munir Ahmed

Six sigma methodology leads to business excellence by improving process quality and reducing variations. It’s a
philosophy which enables processes to produce defect free products. A refrigerant manufacturing company was facing
increased operational cost, low quality, and increased lead time due to high defect rate in Metal Inert Gas (MIG) Welding.
This paper presents an empirical study about the implementation of six sigma Define, Measure, Analyze, Improve and
Control (DMAIC) methodology in MIG Welding facility of Heat Ventilation and Air Conditioning (HVAC) manufacturing
plant. Critical factors were identified and analyzed by using Ishikawa diagram and hypothesis testing. Fitted linear model
was used to identify optimal setting of process parameters. After-effects of project reduced the defect rate up to 25%
operations cost (US $ 0.8 Million), and customized the sigma level from 2 to 4 sigma.