Taguchi Designs

The goal of the Taguchi method is to find control factor settings that generate acceptable responses despite natural environmental and process variability. In each experiment, Taguchi’s design approach employs two designs called the inner and outer array. The Taguchi experiment is the cross product of these two arrays.

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The control factors, used to tweak the process, form the inner array.

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The noise factors, associated with process or environmental variability, form the outer array.

Taguchi’s signal-to-noise ratios are functions of the observed responses over an outer array. The Taguchi platform supports all these features of the Taguchi method. You choose from inner and outer array designs, which use the traditional Taguchi orthogonal arrays, such as L4, L8, and L16.

Dividing system variables according to their signal and noise factors is a key ingredient in robust engineering. Signal factors are system control inputs. Noise factors are variables that are typically difficult or expensive to control.

The inner array is a design in the signal factors and the outer array is a design in the noise factors. A signal-to-noise ratio is a statistic calculated over an entire outer array. Its formula depends on whether the experimental goal is to maximize, minimize or match a target value of the quality characteristic of interest.

A Taguchi experiment repeats the outer array design for each run of the inner array. The response variable in the data analysis is not the raw response or quality characteristic; it is the signal-to-noise ratio.

The Taguchi platform in JMP supports signal and noise factors, inner and outer arrays, and signal-to-noise ratios as Taguchi specifies.

Contents

Overview of Taguchi Designs

Example of a Taguchi Design

Taguchi Design Window

Responses

Factors

Choose Inner and Outer Array Designs

Display Coded Design

Make the Design Table