- Isothermal viscosity data was produced for LY556, LY564-1, RTM6 epoxy and Arotran D6530 polyester resins.
- Measurement of non-injectable point, thermal conductivity and kinetic data for the above was also produced
- Permeabilities of a range of fabrics, volume fractions and lay-ups were measured using different experimental set-ups. Poor agreement was found between the methods employed at different sites and further research is needed.
- Preformability was dependent on the mould design and fabric type but little affected by the applied pressure. The thermosetting nature of the carbon size used made vacuum bag forming preferable to press forming. Postforming handling should be minimised.
- Within experimental limits, edge effect investigations showed faster flow with smaller gaps, but the variable architecture of the cut fabric edge made quantitative analysis impractical.
- Flow rates increase with clustered fibres relative to uniformly distributed fibres, but the effect of the first flow enhancing tow is much greater than that of subsequent tows.
- Within experimental limits, the mechanical properties were little effected by variations of processing parameters, but the flow enhancing tow reduced some mechanical values.
- Dielectric analysis can be used to follow the in-situ curing of epoxy resins.
- The mould-filling software gave generally good flow-path and dry spot predictions but variable fill-time predictions (both under and over) which is related to the 'correct' permeability value. Further software development is required.
- A succesful RTM injection is dependent on many factors including: fabric permeability; resin temperature, viscosity/cure/reactivity; pressure/vacuum; mould design and temperature; fill path length; injection and exit ports position and configuration; flow join lines; and component complexity.
- PC based simulation and IKBS systems are preferred to mainframes for SME use.
- Practical experience and data is needed to develop simulation and IKBS software.
- It was found easier to start with a complex IKBS model and degrade the complexity within the model than to start with a simple model and increase the level of complexity.
- Simplified methods have been demonstrated to optimise resin cure cycles.
- Void formation, transport and dissolution in the RTM process is complex process depending on factors including: resin type; gas solubility; capillary effects; temperature; and viscosity.
Resin Transfer Moulding (RTM) is a manufacturing process attracting interest from both the high and low volume manufacturing areas of the composites market. The current state of the art is housed in companies which have gathered their expertise over many years. Those wishing to enter the field have to undergo a learning process for each component before the production method is sufficiently developed. While the costs associated with this development may be acceptable for high volume manufacturers, for manufacturers with a range of components at a low production rate it is difficult to absorb this cost.
The proposed research programme intends to address the current short-fall in expertise by developing techniques for the design of the RTM process for high performance components. This will be achieved using improved material characterisation techniques for both resin systems and reinforcements. The properties resulting from this work will subsequently be incorporated in both a process simulation model to assist in process design. The model will be validated using a series of increasingly complex components, until ultimately a fully three dimensional item incorporating a range of features will be moulded. In parallel, the data gained from the material characterisation and moulding work will be incorporated in the Intelligent Knowledge Based System (IKBS); with the rules governing the system validated at the same time. As a result of this project it is expected that RTM will be introduced into a wider range of manufacturing applications.
Funding SchemeCSC - Cost-sharing contracts
19002 Peania - Attika
20009 San Sebastian
BT3 9DZ Belfast
2600 JA Delft
SP10 5LU Andover