A Six Sigma Approach for Chipping Elimination in Porcelain Storage Tanks

摘要

The application of Six Sigma methods to reduce chippage on enameled steel tanks is described. CST Storage in DeKalb, IL manufactures porcelain coated steel tanks in a 650,000 ft2 facility in 2 shifts with 90 people. Enamel application is 3 coats of glass on a high strength low alloy (HSLA) steel substrate fired at 1560°F. A continuous improvement project was initiated to reduce chippage rejects. The associated scrap and rework costs were over $160,000. A structured Six Sigma approach was deployed.Six Sigma offers a set of tools for problem solving in manufacturing. Philosophically, it is fact-based, data-driven, and customer centric. Inputs and outputs are controlled, and outputs are expressed a function, y = f(x) of the inputs. Six Sigma uses qualitative and quantitative tools to drive process improvement and improved product quality. The methodology uses a structured and rigorous five phase approach of DMAIC: IDefine -JVleasure -Analyze -Improve -Control. Insimple terms, Six Sigma quality performance means 3.4 defects per million opportunities.