Challenges for Modelling Filling during Liquid Composite Moulding Processes
S. Bickerton, M. J. Buntain, P. A. Kelly
Centre for Advanced Composite Materials, The University of Auckland
New Zealand

Keywords: RTM, Reinforcement, Consolidation

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In recent years a resurgence of interest has been expressed in closed mould manufacturing techniques for fibre reinforced
thermoset polymers, primarily due to the potential to carefully manage hazardous gaseous emissions, and the ability to
address complex part geometry. The term Liquid Composite Moulding (LCM) encompasses a growing list of composite
manufacturing processes, including Resin Transfer Moulding (RTM), Injection/Compression Moulding (I/CM), and the
Seeman Composite Resin Infusion Moulding Process (SCRIMP) to name a few. This list has grown with the increasing
diversity of applications, currently applied LCM techniques offering a range of solutions suitable for products of all sizes,
and manufacturing scenarios from prototyping to mass production. The majority of previous mould filling research has
focussed on RTM, for which which two-piece rigid moulds are used, and we have the luxury of assuming constant cavity
thickness. In this paper we discuss an approach to modelling filling of LCM processes in general, highlighting the challenges
that must be overcome.

All LCM techniques involve compressive deformation of the reinforcement (or preform) prior to, and in many cases during the
filling process. Several of these processes involve significant dynamic cavity thickness changes during processing. As both
the flow characteristics, and deformation behaviour of reinforcements are sensitive to cavity thickness, determination of resin
pressure requires solution of strongly coupled equations. A one-dimensional consolidation model has been applied to predict
filling and evolution of internal mould forces. This approach requires accurate knowledge of preform permeability as a function
of fibre volume fraction, and a good model for the deformation response of the reinforcement. Development of a suitable
deformation model is discussed, and applied to model filling during several LCM process variations.