Problem Solving With 6σ

Case Study


To reduce the scrap rate of an assembly from 7.7% to under 2% in six months.

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Problem Definition

DISHER and our customer’s team met on site to observe the failure modes and define the problem. Four possible contributors for the high scrap rate were identified.

Test & Measure

DISHER applied a Design of Experiment (DoE) to assess the relevance of each of the four factors in question. The current state was tested and measured.


DISHER and the customer analyzed the results from the plant trials and concluded that the screw type was the root cause. It was the most significant factor in causing the defects to occur.

Recommend & Improve

Backed by data, the team confirmed a recommendation to implement a design change which replaced the current screws with dog point screws. The change was approved and implemented by the customer. The team verified the improvement through measurement.

Results & Control

8-months later, the scrap rate went down from 7.7% to .35% on a production rate of 35,000 units a week. Scrap costs were reduced and throughput capacity increased.