Pontis, Twenco and Siemens Gamesa seek to demonstrate welding of large thermoplastic composite structures

A Dutch-Spanish consortium consisting of Pontis Engineering, Twenco and Siemens Gamesa Renewable Energy, kicked-off the joint UP-WELD project seeking to demonstrate the welding of thermoplastic structures of more than 100 meters long and the feasibility of recyclable blades.

New developments in material technology enable the manufacturing of large fibre reinforced components using thermoplastic materials as a matrix instead of thermosets. Thermoplastics offer the possibility for recycling by re-melting or depolymerisation. Hence, using thermoplastics in large fibre reinforced structures is an attractive preposition – and in line with Siemens Gamesa’s aspiration to design and manufacture fully recyclable wind turbines.

Scaling up welding to an industrial scale

An added advantage of thermoplastics is that they can be joined using welding technologies instead of paste adhesive, significantly decreasing manufacturing time and the use of adhesive products. Currently, welding of thermoplastic parts up to 2.5 m has been demonstrated, but to take the full advantage of the recyclability and manufacturing efficiency of thermoplastic fibre reinforced composites, scaling-up the welding from a laboratory to an industrial scale with welds of more than 100 meter of length is crucial.

The objective of the UP-WELD project is to evaluate and demonstrate the scale-up of current thermoplastic welding technology to enable welding of large size components with welds of over 100 m length. The project runs from NOvember 2020 to December 2022. The project has received regional funding through the EU-funded MANUNET project.


Pontis Engineering is the project coordinator and will carry out process evaluation and determine welding parameters for the development of the chosen technology for large welds to perform a larger scale test to demonstrate the proof-of-concept for upscaling.

Twenco will use its expertise in sensor development for process monitoring and control during the welding process, improving the quality of the final product.

Siemens Gamesa Renewable Energy will provide knowledge regarding the requirements for industrialisation of the process, thus ensuring that the outcome of the project meets company needs and aspiration of weldable, recyclable blades in the future.

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