Add Constraints Tool

The constraints tool makes the process of calculating constraint inequalities as easy as possible. Extreme combinations of factors (a vertex) will not produce a meaningful and/or measurable response. To use the constraints tool, identify the problem vertex to exclude from the design. For each factor answer this question, “if all the other factors are at the excluded vertex, how close can the remaining factor be set?” The answer defines the constraint point for each factor.

Select the vertex to be excluded by changing the settings in the Vertex column. For each factor (row), enter the setting in the Constraint Point column. Press OK and the constraint will be calculated. If a factor can be set at the vertex with all the other factors change the entry in “< > skip” to “skip”.

There is no constraint tool for mixture constraints. Mixture constraints are generally linked to a physical property rather than an excluded vertex. For example, if there must always be at least twice as much of component \(A\) than there is of component B, then you can directly enter the constraint as \(0 \leq A - 2B\).

See also Constraint Tool Examples for several complete examples that utilize the Add Constraint Tool.