3D printing of a mold for the wind turbine blades can lead to cost-savings within the product development cycle, and the technology also makes it easier, and cheaper, to add more functionality into components, the Offshore Wind Infrastructure Application Lab (OWI-Lab) reports.
Wind turbine blades produced for research purposes can easily be more than 12 meters in length, which is to date too long to be printed in one run. This is why the Advanced Manufacturing Office (AMO), part of the US Department of Energy, together with a number partners, started the research to the use of 3D printed sections of almost 2 meters which can be used to make large molds to produce a full blade.
Projects like this one require larger 3D printing capacity and the AMO team managed to locate it at the Manufacturing Demonstration Facility (MDF) at the Oak Ridge National Laboratory, Tennessee, USA, which houses a so called ‘Big Area Additive Manufacturing’ (BAAM) 3D printer. The equipment tends to be 500 to 1000 times faster than most other industrial 3D printers and has a building capacity that is many times greater.
Although this type of 3D printer is not quite capable of working at the actual dimensions required for a full blade, it does provide a realistic overview on how to take on such projects in practice, according top OWI-Lab.
First of all, a CAD model of the blade was designed: in principle a typical blade design from which a mold was made and cut into 3D printable sections, complete with assembly holes and discharge ducts for the hot air. Sections measuring almost two meters were then 3D-printed.
These sections were then given a glass fiber laminated layer and smoothed off. Each mold segment was placed in a frame with a hot air blower, temperature control and thermocouples.
The innovative technology using hot air saved energy and eliminated the labor-intensive step of manually installing the heater wires, which are traditionally embedded into the mold., OWI-Lab said. Moreover, the air blowers can be reused for new molds in the future.
Once assembled, the gigantic 3D printed mold had an extremely uniform surface, perfect for manufacturing wind turbine blades or tidal generator blades at a lower cost when using the traditional production methods, according to OWI-Lab.
Various blades were produced as demonstrator during this research project using the 3D printed mold.