Reliability Engineering

Design of Experiments (DOE) and the Taguchi Approach

optimize = meet the target / variation with minimum efforts, target + variation vs factors, minimum trial and error experiments, which factors for variation / mean

chart = up / down + interactions

- Optimize product and process designs, study the effects of multiple factors (i.e.- variables, parameters, ingredients, etc.) on the performance, and solve production problems by objectively laying out the investigative experiments. (Overall application goals)

- Study Influence of individual factors on the performance and determine which factor has more influence, which ones have less. You can also find out which factor should have tighter tolerance and which tolerance should be relaxed.

DOE using Taguchi approach attempts to improve quality which is defined as the consistency of performance. This can be done by moving the mean performance to the target as well as by reducing variations around the target. The prime motivation behind the Taguchi experiment design technique is to achieve reduced variation (also known as ROBUST DESIGN).

Further, the experimental data will allow you determine:

- How you can determine which factor is causing most variations in the result

- How you can set up your process such that it is insensitive to the uncontrollable factors

- Which factors have more influence on the mean performance

- What you need to do to reduce performance variation around the target

- How you can adjust factors for a system whose response varies proportional to signal factor (Dynamic response)

Introduced by R. A. Fisher in England in the 1920's

The Taguchi Approach , Dr. Genechi Taguchi DOE techniques in the late 1940's