Systematic investigation of process and product variations in a spindraw-winding process

The variation in product quality of industrial poly-ethylene terephthalate (PET) produced in a spindraw-winding process was related to on-line measure d process variables. An experimental design in three process variables was used to introduce meaningful variation. Using standard multivariate data an alysis techniques the relation between the variation of the product quality and the process variation could be modeled. The adequacy of these models w as judged by comparing the modeling error to the known measurement error of the quality variables. It Could be established that the three process vari ables that were used in the experimental design are responsible for almost all variation in product quality. This shows the feasibility of the multiva riate approach to systematically analyze the variation in product quality o f industrial processes. (C) 2001 Elsevier Science Ltd. All rights reserved.