Models for Quality Selection and Their applications in the Pulp and Paper Industry, 1990 Process & Product Quality Conference Proceedings

The purpose of this paper is to demonstrate the idea behind quality selection and its’ application.

Deming’s (1986) 14 points have been a great source of inspiration for the rapid development in the quality control field. One result of his philosophy of management policy is the more intensive and systematic use of statistical methods. Deming’s philosophy has contributed to an increasing interplay between the supplier and the producer (partnership). Partnership implies among other things that a clear agreement should be developed with the supplier about the methods by which conformance to the purchaser’s requirements should be verified. Since the customer’s quality requirements are an essential part of Quality Selection models, methods to assure agreed quality under partnership are of interest. The idea of partnership has also been followed by supplier certification programs, e.g -IS0 9000-9003 (1987) and the guideline IS0 9004 (1989).

Models for Quality Selection are helpful when the aim is to estimate the optimal level for certain quality variables.

The purpose of this paper is to demonstrate the feasibility of such models as applied in the manufacture of kraft liner, e.g one quality variable and two quality levels. A brief outline about how to generalize these models for application on for instance the production of fully bleached kraft pulp e.g two variables and several quality levels will also be given.

In the paper manufacturing process, there will always be a variability in the quality characteristics of interest, as given in this picture (Fig. 1). The process is stable around its’ process level, with a certain variability expressed by the standard deviation.