Engel Austria, which is a specialist of injection moulding and automation, is transferring proven high-volume manufacturing principles to lightweight composite applications. At the latest edition of JEC World, the manufacturer presented the efficient, integrated process it developed, which brings together the key steps – placing the reinforcement layers, forming, functional integration and removal of the finished rotor blade – in a continuous cycle within the injection mould.

Lightweight, strong and near-net-shape: tape-sandwich injection moulding as the core technology

The central element of the demonstrated process is a structural sandwich design consisting of carbon-fibre-reinforced thermoplastic tapes and an injection-moulded short-fibre compound. The tapes form the load-bearing outer layers of the rotor blade are positioned precisely in the mould and secured using vacuum fixation. This allows the reinforcements to be aligned exactly along the load paths – material is used only where it is needed for structural performance.

In the next step, the core material made of a short-fibre thermoplastic is injected between the pre-positioned tapes and bonded to the outer layers to form a near-net-shape component structure. To further increase the lightweight potential, the core is foamed chemically, reducing component weight while maintaining structural performance.

The result is a lightweight yet highly durable rotor blade in which shaping, structural function and material bonding are realised in an automated cycle. After a defined final trim, the component is ready for use.