Department of Industrial Engineering

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Browsing Department of Industrial Engineering by Author "Ahsan, Qazi Zohaib"

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    Reduction of defects in a manufacturing company using six sigma methodology
    (University of Management and Technology Lahore, 2016) Ahsan, Qazi Zohaib; Zafar, Arslan; Rahim, Syed Jalal
    In this project, a case study on implementing the Six Sigma DMAIC (Define, Measure, Analyze, Improve and Control) methodology in a manufacturing company is presented. Different types of gears are manufactured in the company. Some types are cam shaft gear, Idler gear, fuel pump gear and fly wheel ring gear. The customers used these gears in tractor and fly wheel ring gear is used in car. In our case study idler gear was chosen for the implementation of DMAIC methodology. This problem will be tackled by implementation the Six Sigma DMAIC methodology. Failure to achieve the required outer diameter according to tolerance is the problem. Idler gear is the most critical component in the tractor. It is used with the combination of cam shaft gear and fuel pump gear. The purpose of these gears is to transmit the motion to the wheel. Failure to achieve in between outer diameter according to tolerance is the problem. The required outer diameter of Idler gear is 233.40 mm with a tolerance of ± 0.05 mm. So the outer diameter of the idler gear must to be between 233.35 mm and 233.45 mm. In past Six Sigma was implemented belt based training structure, so it was most expensive approach. Today we can implement DMAIC methodology of Six Sigma with less cost. In this background, an attempt was made to find out the root causes of defects in idler gear by employing Six Sigma DMAIC Methodology. The Sigma level of existing process is just 1.22. We was determined to the root causes of the defects in gear and made some suggestions for the company. These root causes are CNC lathe machine, cutting tool geometry and choice of the best combination of speed and feed rate. For that purpose we have designed an experiment and based on results we can choose the optimal combination. By implementing these suggestions company will be able to overcome the defects in idler gear and others as well. After reduction of these defects the sigma level will be increase by improving the process capability. DMAIC methodology is an effective tool for breakthrough improvement. This will enables the company to spend less cost to obtain Six Sigma level quality. Hence, DMAIC is the promising methodology to obtain maximum productivity and efficiency with less cost.