Application of six sigma methodology for a manufacturing cell — A case study

A medium scale Auto Component manufacturing unit produces Link, Valve, Motor Piston, CAM shaft and Universal joint. The initial study revealed that 80% of total defects were due to link component. The 1500 parts / day of link is produced. The work carried out focused on improving quality of link using Define, Measure, Analyze, Improve, Control [DMAIC] methodology. A supplier, Inputs, Process, Outputs, Customers [SIPOC] and High level process mapping was used as tools. There were 11 Critical To Quality [CTQ] parameters identified. Low sigma value for outer diameter was traced by conducting Process Capability Studies. Causes for Low Process Capability [Cp] & Process Performance [Cpk] values were determined through brainstorming. Failure Modes and Effects Analysis [FMEA] was also used to understand effects of different parameters and methods to control. The outcome of the work improved sigma level for outer diameter increased from 1.96 to 4.83.