Vacuum Infusion What are the Benefits? What production system are you using now? Are you using vacuum bagging already or working open mould methods? Are you in pre-preg production (autoclave or oven cure) or liquid resin systems? Depending on the production methods currently used, the key benefits you will see will vary. 1
Benefits for Pre-Preg (Oven cure / autoclave users) Lower cost production method Potential to make near pre-preg quality laminates Large part production to high laminate specification Reduced cycle time potential Localised repairs and corrections during processing, monitoring of the actual process is much easier. Benefits for open mould / liquid resin users Reduced air voids and significant improvement in the laminate structure and performance Fixed methodology reducing variation due to operator error. Reduced waste optimisation of fibre and resin usage. Reproducible results. Cost effective solution to produce high value / quality components Larger components produced in a more controlled and cost effective manner. 2
Key Industries using resin infusion Marine Hulls Decks Reinforcing structures Masts Wind Energy Turbine Blades Nacelles Spinner cones Aerospace Interior panels Aircraft Nose Cones Seats Radomes Building & Construction Bridges Radio telescopes Facades (cladding) Swimming pools 3
Wind Energy Single biggest industry to use vacuum infusion as the main production method. Typical mould turn-around for a 40M blade 18 hours. High performance laminate Cost effective Consistent results Minimal waste Typical infusion cost max of 3.5% of material cost of blade. Typical wind turbine production 45M Blade shell Infusion time 1 hour 4.25 tonnes per shell total weight Deviation of weight from standard 20Kg Epoxy / foam core / glass fabric construction Typical factory has a minimum of six mould sets. All producing one complete blade every 18 to 24 hours six day per week. 4
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Marine Infusions MAT - Turkey Southern Wind Shipyard Cape Town, RSA. Marine Infusions SERIGI 53 Infusion 6
Planning Infusion Set ups Ask for help! Involve resin, fabric and vacuum bagging suppliers right from the start! Flat plate trials test the laminate structure and resin combination to determine resin flow characteristics. Start with simple structures Learn the basics! Demonstrations. 7
Key Influencing Factors In Vacuum Infusion 1. Atmospheric Air pressure 2. Humidity & water vapour 3. Fibre pack permeability 4. Resins viscosity & gel times Atmospheric Pressure The driving force in vacuum infusion: Resin is pushed into the vacuum created in the dry laminate by air pressure. We therefore need to be aware of the air pressure in the area in which we are working. (Johannesburg 1753M) Fraction of 1 atm 1 3/4 1/2 1/3 1/10 average altitude (m) (ft) 0 2,750 5,486 8,376 16,132 0 9,022 18,000 27,480 52,926 1
Humidity & water vapour Reinforcement must be kept in dry conditions. In epoxy infusions water held in the fabric can often be seen to be pushed in front of the resin flow this can cause the bond between the sealant tape and the bagging film to fail. Excessive water can also affect the cure of the resin systems, cause fibre whitening, and generally reduce the quality of the finished laminate. Most vacuum films have a nylon content which is hygroscopic. It is therefore affected by atmospheric humidity. In very low humidity it can become brittle and loose its elasticity, in high humidity it can become very soft and difficult to handle. Bagging films should always be stored in the conditions specified on the data sheets. Fibre Pack Permeability Darcy s law can be used to predict the rate of flow. In theory! Darcy s Law There are some major issues which make it impractical to use in most applications. Availability of data permeability data for many reinforcements can be difficult to obtain and often has a wide tolerance. Resin viscosity varies with temperature. Using combinations of materials different fabrics, cores etc. Diagram showing definitions and directions for Darcy's Law. Ultimately there is no substitute for performing trials on the proposed laminate under workshop conditions to determine the flow rates. 2
Aerovac systems Ltd. Richmond Aerovac is a global company with 30 years experience in the advanced composites industry. We develop, manufacture and distribute high performance materials and product solutions including all vacuum bagging consumables for resin infusion and pre-preg processing, as well as specialist reusable rubber products and composite tooling. Founded in 1980, Aerovac, formerly a family run business, was acquired by UMECO plc in 1999. Richmond Aircraft Products was acquired in 2000. UMECO is Europe's leading provider of value added distribution services to the aerospace and defence industries. Today Richmond Aerovac UK operates out of two custom built facilities in Keighley, West Yorkshire, employing 40 staff with an annual turnover of around 15m. This is generated from sales of our specialist high temperature rubber forming products and consumable process materials used in the manufacture of advanced composite materials. 1
Richmond Aerovac manufactures and supplies a full range of products for all vacuum bagging systems. These include bagging film, peel ply, release film, breather fabric, sealant tapes, adhesive tapes, vacuum hoses, fittings and other ancillaries. VMS2 (Vacuum Membrane System) A C B D A = Release Film upper B = Breather Mesh C = Resin Barrier Membrane D = Perforated Release film lower. 2
VMS2 resin barrier vacuum line Resin cannot travel onto the top surface of the membrane Vacuum Connection Airflow Resin Flow Laminate VMS2 (Vacuum Membrane System) Reduced number of vacuum ports required - VMS2 will work in lengths up to 50M with one vacuum port Reduced flange width requirement - because the VMS2 sits on the laminate there is no need for an extra wide flange on the mould. Sits flat under the vacuum bag and poses no burst risk, as can be experienced with spiral hose and other vacuum network systems. VMS2 resin barrier vacuum line 3
Faster infusions - VMS2 allows the easy introduction of vacuum at intermediate points between resin inlets channels thereby reducing the distance the resin has to travel and speeding up the infusion process. Very easy to position (compared to spiral and other channel systems) with minimal or no 'mark off' on the finished product. No resin draw into the vacuum system - allows accurate calculation of the resin content of the laminate. No waste resin in vacuum hoses & catch pots. VMS2 resin barrier vacuum line Virtually eliminates the risk of vacuum 'lock off' when used correctly Elimination of dry spots - because the VMS2 can be safely placed anywhere on the mould, network design is greatly simplified allowing the network design to cover any problem areas easily. VMS2 resin barrier vacuum line 4
Can be used as one continuous vacuum system or as 'spot' location vacuum points. Release film base allows VMS2 to be easily removed after the infusion. VMS2 resin barrier vacuum line Infusion of a wind turbine blade shear web The shear web is a very critical structural part of the blade transferring huge loads across the blade. On this blade shear web, VMS2 makes the link between the built in vacuum channel and the part. The advantage of the VMS2 is that we can lay on to the flow mesh, keeping an high vacuum level at the resin front. The quality of the laminate is critical dry areas and voids must be avoided. VMS2 resin barrier vacuum line 5
Infusing with no technical flange at CATANA Catamarans. VMS2 is laid all around inside the part as the vacuum channel. VMS2 resin barrier vacuum line VMS2 resin barrier vacuum line Available only from Richmond Aerovac through our sole distributor to the African composite market. AMT Available in three widths 100, 150 & 200mm 6