Process analysis for adaptive control, applied to injection moulding

Abstract

The application of system analysis to plastics injection moulding process is discussed. In contrast to well-known methods of white box modelling, which use insight into the physical phenomena of the process, the experimental approach of black box modelling is considered. This way of system analysis is intended to yield mathematical process models describing the static and dynamic relations of system outputs to input variables.

Mathematical models must be as simple as possible to be used in on-line computer control, including the adaption of models and control algorithms to unknown operating conditions. The paper presents examples of experimental modelling, utilizing real data from injection moulding machines. Results of injection stage modelling and of production cycle modelling are given. The latter models relate the product features weight and length to machine settings and can be updated on-line. The adaptive computer control scheme for feedback of moulding properties is outlined.