Research Article
Muhammad Mudassar Sharif, Z
Abstract
Six sigma methodology leads to business excellence by improving process quality and reducing variations. It’s aphilosophy which enables processes to produce defect free products. A refrigerant manufacturing company was facingincreased 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 andControl (DMAIC) methodology in MIG Welding facility of Heat Ventilation and Air Conditioning (HVAC) manufacturingplant. Critical factors were identified and analyzed by using Ishikawa diagram and hypothesis testing. Fitted linear modelwas 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.