COMPOSITES EUROPE 2012 Blog

Every movement must be just right when the blade and rotor hub of a wind turbine are married together at a dizzy height.  Because screwing the rotor blade onto the rotor hub 100 metres above the ground represents a major bonding technology challenge. Heavy-duty threaded bushes are bonded into the fibre-reinforced flange on the blade holder of each blade – and the bond must be absolutely rock solid.

The epoxy resin and polyurethane need to be mixed to just the right ratio to ensure that the inserts are properly bonded. To automate this process safely and reliably, the Hessian family-owned company Tartler has developed multi-component metering and mixing systems which meet precisely these requirements – for example a customised version of its Nodopox 200 M/U. With an output of less than 0.2 litres per minute and a mixing ratio accuracy with less than two percent deviation, the threaded bushes can be bonded to withstand the tensile force of over 20 tonnes.

The system has a decisive process engineering advantage: its uses the original packing drums of the material manufacturer.  It pumps the two high-viscosity components directly from the 200 litre drums, which contain no bubbles and some of which have been vacuum-filled.  Depending on the material used, this does away with the need for stirring the mixture and transfering it to the work dispenser.  The components can then be heated to the required processing temperature of up to 80° between the pump and the mixing head.

Siempelkamp Handling Systeme is also working on a process for automating the manufacture of rotor blades for wind turbines. The new development automatically brings together and bonds the core material and the covering layer – in a machine with a working width of three metres. All kinds of materials can be used for the core.

A large number of processing steps are still carried out manually in the composites industry, which is why the automation of product stages is now gaining in importance. Numerous examples will be on display at the international Composites Europe (CE) trade fair, to be held in Essen in September, where both Tartler and Siempelkamp will be showcasing their latest products.

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