Multi-grade modelling - paperboard quality modeling

A major limitation of the use of multivariate analysis tools is the constraint of having to build one model for each grade of product produced in a given process. If the process is very limited in the number of grades produced, then an industrial implementation is a trivial case. However, when faced with dozens or hundreds of product grades produced, this is not a trivial problem. We developed a multi-grade modeling technique which allows one to group families of similar products with two models. The first model describes the differences between the grades within the family and the second model describes the similarities between the grades within the family. An example based on Temboard paperboard grades of different thickness is discussed.