Rotor blade manufacturing
State-of-the-art mixing and dosing systems for resin, adhesive and gelcoat applications
Rotor blades are exposed to extreme loads during operation. They must be able to withstand all types of weather conditions. Wind speeds of up to 400 km/h can occur at the tips of a rotor blade. Hail, impact from birds and even raindrops can cause significant damage to the leading edges. In addition, increasingly large turbines are being produced, and the length of the rotor blades and the rotor diameter are growing steadily.
Even the smallest error in production could have serious consequences. This poses particular challenges for the construction of the systems. The components are still manufactured by hand. Although there is a tendency towards automation for certain process, this has not yet become established. For the production of fibre composite components, DOPAG offers special metering and mixing systems that can handle the large material volumes involved in the production of rotor blades and can meet all the current production requirements.
Our product range includes infusion systems with volume outputs of more than 60 l/min as well as bonding resin systems that process compounds of more than 30 kg/min. This ensures minimal mould cycle times. Due to the high resin consumption during infusion and the quality standards of the fibre composite components, resin degassing systems need to be used. DOPAG has a validated system which can degas more than 40 litres of resin per minute. In addition, there is also a wide range of gel coat systems as well as systems for mixing erosion coatings and putties for finishing the rotor blades.
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We offer metering technology for these applications:
LEP + Putty
gluemix: 2K glue dosing system
Expert in wind turbine rotor blade production
Trends in rotor blade production
In recent years, the rotor blades of wind turbines have been getting even larger. Carbon fibre semi-finished products in combination with standard glass fibre materials enable blade lengths of more than 100 metres. Due to the increased need for reinforced fibre layers, mould occupancy times are getting longer. Tonnages for infusion and bonding resins as well as coating materials are increasing. Consequently, the systems for providing mixed materials must meet these growing demands. This also applies to the very high quality standards involved in offshore.
A rotor blade typically consists of glass fibre composites and reinforcement materials such as balsa or foam materials in order to transmit the shear stresses. The production process begins with the manufacture of the upper and lower shells. For the first layer, a gel coat is applied using the gelcomix metering system to give the component a high-quality surface finish. Dry semi-finished fibre products are then placed in the mould, auxiliary materials are added, and then the entire component is sealed vacuum-tight with a film and evacuated. This ensures the maximum freedom from pores.
Further steps include degassing the infusion resin and the actual infusion process. Degassing is necessary because some air bubbles can collect in the material due to contact with the air and due to transportation, which can result in undesired air pockets in the fibre composite during vacuum build-up. Degassing reliably removes even the smallest bubbles from the material. The compomix BL infusion system is connected directly to the vacuum build-up by means of tubes. Alternatively, buffer tanks are also possible, which are supplied with mixed material and also connected using infusion tubes. The mould is set after infusion. The temperature is closely monitored and controlled during this process in order to prevent material damage due to the exothermic reaction of the resin.
Once the component is fully set, all auxiliary materials are removed and the bonding process of the stiffening elements and the two shell halves begins. The adhesive beads are applied with a gluemix binding mix system. Once this process is complete, the two halves of the mould are closed up and a complete rotor blade is created.
Bonding and sealing is becoming an increasingly popular method of joining components without screws. With DOPAG systems, applications can be realized reliable and precise.
DOPAG offers reliable solutions for the manufacture of fibre composite components, for example RTM, Filament Winding, Infusion, Pultrusion, etc.