Clean Wet-Filament Winding New Technology Developed by UK Consortium Being Showcased at JEC Europe 2013, Paris from the 12-14th March

This new, environmentally friendly, wet-filament winding technology offers a clean and efficient method of production of high-performance composites. Unique design components in this new wet-filament winding technology include a custom-built modular fibre bundle spreading station and a mixed resin fibre impregnation unit, which together provide effective fibre wetting. Waste and solvent usage is also significantly reduced compared with traditional wet bath filament winding production; up to 80% less cleaning solvent consumption has been achieved, along with an equivalent reduction of mixed resin waste. A variety of thermosets, including faster curing resins, have been successfully trialled with this new clean filament winding technology, which can be retrofitted and adapted for other manufacturing processes, such as pre-pregging and pultrusion.

This new technology is being showcased at the JEC Europe 2013 exhibition in Paris by the UK consortium on the Pultrex stand (U39). Commercial representatives from both Mouldlife Ltd. and Pultrex Ltd. will be available during the show for discussions with any companies interested in acquiring this new technology, which is being offered globally under licencing agreements.

Next generation technology

The traditional bath-based impregnation method, which has been the predominant filament winding technique used for thermosetting resins by the composites industry over the last 50 years, has until now remained largely unchanged. This new, environmentally friendly, clean production technology, with improved productivity and significantly less waste, offers a next generation alternative technology for manufacturers, which can be retro-fitted to existing filament winding machines.

With this new ˜clean' wet-filament winding process the conventional wet resin bath is replaced by the modular mixed resin fibre impregnation unit, typically mounted on the traverse-arm of the filament winding machine, close to the mandrel. The thermoset resin and hardener are contained in separate reservoirs, metered electronically and delivered on-demand by two precision gear-pumps via a custom-made manifold into the static mixer, which is connected to the mixed resin fibre impregnation unit. The system is able to apply a very precise volume of mixed resin to impregnate the fibre bundle, so minimising over-impregnation; the precision pumps fitted in the fully operational prototype are capable of delivering 10“110 g.min-1 of resin and hardener and handling liquids with viscosities of 20“10,000 mPa.s. A feedback control system between the rotating mandrel and the resin dispensing unit is used to control the relative throughput of the resin and hardener. The resin dispensing unit was manufactured by CTM Ltd., which is also part of the UK consortium. A schematic illustration of the Clean Technology filament winding concept is presented in Figure 1.

The other important component in this clean wet-filament winding technology is the fibre bundle spreading station; the controlled spreading out of the fibres prior to resin impregnation increases the width of the tow and at the same time reduce its nominal thickness. This has the positive effect of efficiently increasing the impregnation of the mixed resin system into the fibres prior to being wound onto the mandrel. A schematic diagram of the complete process is shown in Figure 2.



Productivity and cost benefits

For manufacturers, there are several major productivity advantages over a conventional wet resin bath in using this new filament winding technology with its metered static mixer and resin impregnation head. The custom built metering system automatically draws the resin and hardener in the required stoichiometric ratio as needed from the individual bulk reservoirs. This eliminates the need to do any pre-weighing and manual mixing of the resin and hardener, with the subsequent benefits of no longer needing to use any disposable consumables, such as containers, stirrers and paper and, more importantly, avoiding the problem of air entrapment, a real issue with manual mixing. The other key productivity and cost saving gain of this new automated clean technology system is that the process can be truly ˜continuous' and not limited by the mixed resin volumetric capacity of a wet bath, which must be replenished manually; the resin and hardener reservoirs can be replenished during production with no interruption to the line.

Less cleaning and waste

This significantly cleaner wet-filament winding process, which has achieved up to an 80% reduction in cleaning solvent consumption along with an equivalent reduction of mixed resin waste, is due to two key factors. Firstly, with no resin bath, the need to thoroughly clean the equipment at the end of each production run is eliminated; depending on the dimensions of the resin bath, the cleaning operation consumes several litres of solvent plus the associated consumables, which all have to be disposed of along with the waste mixed resin; the need to take exotherming precautions with waste mixed resin is also eliminated. Secondly, the unit has been designed such that final roller of the resin applicator is positioned above the mandrel. Therefore, unlike a conventional wet-filament winding process, with this configuration the problem of resin dripping from the impregnated tows on to the floor is eliminated.

UK consortium members

The UK Consortium members of this collaborative project are: The University of Birmingham; Mouldlife Ltd; Pultrex Ltd; CTM Ltd.; Halyard Marine Ltd.; Luxfer Gas Cylinders Ltd., PPG Industries Ltd., and Bruker Ltd. The project started in 2010 with backing from the UK's innovation agency, The Technology Strategy Board, a Government funded body which helps companies develop and commercialise new manufacturing innovations

Global licencing opportunities

With reference to commercialising the technology for retrofits and new-build filament winding machines, the commercialisation is being led by Julian Ferries of Mouldlife Ltd and Colin Leek of Pultrex Ltd respectively. They are the key contacts for interested parties looking to acquire this new clean technology; the UK consortium is looking to market licencing agreements globally.

For further information and to book a meeting at the Pultrex stand (U39) during JEC Europe 2013, contact Julian Ferries, Director, Mouldlife Ltd, +44 (0)1638 750679, email Julian@mouldlife.co.uk , or Colin Leek, Managing Director, Pultrex Ltd. +44 (0)1206 395559 email Colin@pultrex.com .

To find out more about the UK consortium project and Mouldlife Ltd., visit www.mouldlife.co.uk.

For further information about Pultrex Ltd., visit www.pultrex.com.

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Release date: 4th March 2013

Photo 1: Prototype Clean Technology filament winding unit

Photo 1 Caption: A fully operational prototype of the new clean wet-filament winding technology, developed by The University of Birmingham's School of Metallurgy and Materials and a UK consortium. A variety of thermosets, including faster curing resins, have been successfully trialled with this new clean filament winding technology, which can be retrofitted to existing filament .

Figure 1: Schematic illustration of the Clean Technology filament winding concept .

Figure 2 “ Schematic Illustration of the clean filament winding process.

About Mouldlife Ltd.

Mouldlife Ltd, located in Bury St Edmunds, Suffolk, England, is an ISO9001:2008 accredited speciality distributor and manufacturer of a wide range of polymer resins, including RTV Silicone rubbers and elastomers, Polyurethane elastomers, adhesives and foams, and Epoxy resins and adhesives. Mouldlife is very proud to officially represent the following companies: Huntsman Advanced Materials, Bluestar Silicone Inc, Polytek, Price-Driscoll, Scott Bader and have recently signed a new agreement to act as official distribution partner for 3D Systems, for their comprehensive range of printers and consumables. For more information: Call +44 (0) 1638 750 679 or visit www.mouldlife.co.uk .

About Pultrex Ltd.

Pultrex has specialised in the manufacture of Filament winding, Pultrusion and Pullwinding machinery since 1974. Our current product range embodies over 30 years design and manufacturing experience in high volume production composite machinery. Many of these machine installations are in constant 24 hour per day production environments which demand minimum equipment down times.

This unique design knowledge, coupled with Pultrex, own 25 years' experience in composite profile production, offers it customers the reassurance of leading edge, highly efficient, top quality, reliable production machines to ensure their customers stay ahead of the competition.

Pultrex can offer complete turn-key solutions to companies outside the composites industry. These services can include: Assistance with product design; Factory layout and production costings; Tooling/Mandrel design and manufacture; Product prototyping and testing; Complete factory equipment specification and supply; Technology transfer and training. These services are augmented by Pultrex professionally qualified engineering staff. For further information visit www.pultrex.com

Pultrex Ltd, 18 - 20 Riverside Ave. West, Dale Hall Industrial Estate, Lawford, Manningtree, Essex, CO11 1UN

England. Tel No: +44 (0)1206 395559 Fax No: +44 (0)1206 395222 Email: sales@pultrex.com