# BP&R March 2016

Using nonlinear modelling to REDUCE PRODUCTION COSTS NONLINEAR MODELLING HELPS SPEED UP MATERIALS AND PROCESS DEVELOPMENT IN SEVERAL INDUSTRIAL SECTORS, AND IS PARTICULARLY USEFUL FOR PLASTICS AND RUBBERS, SINCE THE BEHAVIOUR OF POLYMERIC MATERIALS TENDS TO BE COMPLICATED. HERE, BRITISH PLASTICS AND RUBBER PROFILES A CASE STUDY THAT DESCRIBES HOW THE PROCEDURE HELPED FINLAND-BASED EXEL COMPOSITES REDUCE THE PRODUCTION COSTS FOR ITS PULTRUDED FRP PROFILES.

linear Figure 1. Non oduct models of pr oduction pr , es ti er prop tion uc od pr rate and hich w s ic om on ec mposition depend on co ess oc variables, pr mension di d an es bl varia ed to us e ar variables ays to w e in rm te de uction improve prod s economic

T

o improve the production economics of any process, we need to know the degrees of freedom and how they affect the various consequences of the process including its production economics. These relations are usually not very simple, and cannot be described sufﬁciently well by linear models. Nonlinear models, Author: Abhay Bulsari, Nonlinear Solutions Oy, Turku, however, are the solution to this problem. Finland, with co-authors From a limited set of Matti Suominen, Exel experimental data, or sometimes Composites Oyj, Heinävaara from plain production data, (Joensuu), Finland and Kim Sjödahl, Exel Composites Oyj, nonlinear models can be developed which describe the end results of Vantaa, Finland. various variables on the product quality, production rate and production cost. Then with appropriate mathematical tools, it becomes easy to determine more economic ways of producing the product with given constraints on quality variables and process variables. This article describes a glaring case of improvement of production economics of a pultrusion process of Exel Composites in Heinävaara near Joensuu in Finland using nonlinear models developed from experimental data.

Readers of this magazine have read about nonlinear modelling [1-4] so the basics are not repeated here. Nonlinear modelling helps speed up materials and process development in several industrial sectors, and is particularly useful for plastics and rubbers, since the behaviour of polymeric materials tends to be complicated. It is relatively straightforward to go through the procedure to improve the production economics of any production process. In this case of Exel composites (see typical products in Figure 2), we selected one product

Figure 3. A surface plot of bending strength against ﬁbre content and die temperature, while keeping other input variables constant

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