Genichi Taguchi - Quality Loss Function and Robust Design
Genichi Taguchi is a Japanese quality expert, known for the Quality Loss Function and for methodologies to optimise quality at the design stage – “robust design”. Taguchi received formal recognition for his work including Deming Prizes and Awards.
Genichi Taguchi considers quality loss all the way through to the customer, including cost of scrap, rework, downtime, warranty claims and ultimately reduced market share.
Genichi Taguchi's Quality Loss FunctionThe Quality Loss Function gives a financial value for customers' increasing dissatisfaction as the product performance goes below the desired target performance.
Equally, it gives a financial value for increasing costs as product performance goes above the desired target performance. Determining the target performance is an educated guess, often based on customer surveys and feedback.
The quality loss function allows financial decisions to be made at the design stage regarding the cost of achieving the target performance.
Quality through Robust Design Methodology
Taguchi methods emphasised quality through robust design, not quality through inspection. Taguchi breaks the design process into three stages:
Robust Design methodologies allow the designer through experiments
to determine which factors most affect product performance
and which factors are unimportant.
This is easier explained by example. If your business makes cookies from raw ingredients, there are many possible factors that could influence the quality of the cookie - amount of flour, number of eggs, temperature of butter, heat of oven, cooking time, baking tray material etc.
With Genichi Taguchi’s Robust Design methodologies you would set up experiments that would test a range of combinations of factors - for example, high and low oven temperature, with long and short cooking time, 1 or 2 eggs, etc. The cookies resulting from each of these trials would be assessed for quality.
analysis of results would tell you which are the most important
factors, for example oven temperature affects cookie quality
more than the number of eggs.
Citation Information: Swinton, Lyndsay. "Genichi Taguchi - Quality Loss Function." Mftrou.com. December 2004. < http://www.mftrou.com/genichi-taguchi.html >.blog comments powered by Disqus