IE 509 SIX SIGMA QUALITY�CASE STUDY: THE WESTOVER WIRE WORKS 

Presented by Brightspace Group #9 | CATME Team #11

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• Mukul Karandikar
• Sainadh Reddy Sathi
• Alok Varhadi
• Saleem Asfour

Main Objective

• Firstly, we seek to accurately locate the areas with a high number of rejects in the winder manufacturing process of the transformers. 
• Secondly, we offer practical solutions to lower the rate of rejects, increase product quality, and raise overall operational effectiveness in the winder department through a methodical analysis of the available data and with the use of Six Sigma principles.

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Recommendation

• Westover Wire Works should consider undertaking a high-priority Six Sigma project to assess the root cause of high defects in the winder manufacturing area.
• They should initially concentrate on addressing the inaccurate core builds.
• Conducting a root cause analysis to understand why the wrong cores are being used is advised, as it will substantially impact the performance of all three machines, most notably Winder 1— which has demonstrated the poorest performance overall.
• For effective rectification of the issue with incorrect cores, it is suggested to introduce inspection procedures and work instructions. Ensuring each employee reviews these guidelines before product installation will enhance the overall process, leading to significant time and cost savings.

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Conclusion

• The predominant issue leading to non-conformance across all three winding machines is the utilization of incorrect cores, contributing significantly to the total number of rejected items. 
• Examining each machine separately, it is observed that the primary reasons for rejections in Winder-1 are Twisted wire and Broken Leads.
• Meanwhile, Winder-2 primarily faces rejections due to the use of incorrect cores.
• Lastly, Bad Wind and Wrong Core is the leading cause of rejections in Winder-3.

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Pareto Chart for all Winders

• This Pareto chart shows that 'Abraded Wire' and 'Twisted Wire' are the major reasons for the rejects during inspection. 
• They contribute to 50.3% of all rejections.
• This is followed by 'Broken Leads', 'Wrong Wire', and 'Bad Wind' which contribute 16.6%, 12.9% and 11.1% respectively.

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Pareto Chart for winder 1

• 'Twisted wire' and 'Broken lead' alone account for more than 80% of the rejects.
• Least rejects are recorded for 'Wrong core', 'Abraded wire', and 'Bad Wind.' 

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Pareto Chart for winder 2

• Winder 2 performs better than Winder 1. Zero defects occurred in form of twisting wires and broken leads.
• Here, 'Abraded wire' and 'Wrong wire' account for 90% of the rejects

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Pareto Chart for winder 3

• The performance of Winder 3 is the best with relatively low rejects.
• 'Bad Wind', 'Wrong Core', 'Twisted Wire', and 'Failed El. Test' account for 80% of the rejects.

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Pie Chart & Bar Chart

• Both charts show which winder led to the most rejections during inspection. 
• 41.7% of rejected products are from Winder 1, while Winder 2 and Winder 3 produced 37.5% and 20.8% of rejected products, respectively. (Refer Pie Chart) 
• This provides a great opportunity to do further analysis to learn more about the specific reasons that led to significant rejections in each of the three winders.

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Bar Chart

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Bar Chart (continued)

• The above bar chart shows the major defects in products manufactured from each winder which led to rejections.

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Time Series Plots

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Time Series Plot�for Winder #1

• The top rejects belong to the 'Twisted wire' & 'Broken leads' category. 
• As the month end nears, the rise in defects due to twisting of wire grows sharply. On the other hand, rejects due to broken leads seem to be on the decline.

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Time Series Plot�for Winder #2

• Winder 2 excels in having the minimum non-conformities across five categories among all.
• Nonetheless, there are noticeable surges in defects at different intervals resulting from the use of the wrong wire.
• Finally, abrasion is a prevalent issue in Winder 2.

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Time Series Plot�for Winder #3

• Winder 3 delivers the best performance. 
• We see near to zero non-conformities in the three defect categories.
• There are minor spikes in defects due to twisting and the use of the wrong core.
• Also, the case of bad winding seems to be resolved by the end of the month.

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Reflections

• Provision of historic data would facilitate:
• Performing better EDA, 
• Finding hidden trends,
• Developing predictive modelling, etc. 
• There are near zero non-conformities in certain reject categories of Winder 2 and 3. The best practices from these winders can be emulated all across the manufacturing facility.
• The Six Sigma project can be made strategic by following a lean mindset and implementing Total Productive Maintenance (TPM) methodologies.
• To be in business for a long term, it is also important to continually improve and manage all processes. If not kept up to date, then the company runs the risk of the same issue re-occurring once again. 

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