Straightforward, reliable structural principle

The basic concept underpinning our blade structure has not changed since 1978 when we created our very first blades. The design and features of the blades, on the other hand, have undergone considerable development. And the length of the blades has multiplied over the same period, and with it their performance. In other words, we have used a sustainable concept as a basis for further development.

Two shells and two webs

The following two factors were particularly important when we decided on our blade structure:

• Optimising the strength of the blade by placing the supporting material at the outside edges (shells) 
• Minimising the damage by making the surface more robust.

In principle, the resulting structure consists of two glass fibre shells stiffened with two intermediate webs and a light sandwich of foam or balsa wood.

We are constantly optimising the blade design to help reduce the costs incurred by our customers, the wind turbine manufacturers. For example, our new root concept, SuperRoot, means that the blades can be around 20% longer without increasing the diameter of the blade root. The reduced size of the bolt circle also reduces the cost of the pitch bearings.

Glass fibre has unique benefits

Glass fibre is a unique material in terms of controlling the strength and rigidity of a structure. We can change the pattern of fibre orientation when creating the blade in order to strengthen critical points so they can handle the forces to which they are exposed during operation. For example, the fibres can be laid crosswise to ensure that the blades do not rotate too much.

Glass fibre/polyester also has properties that can be stretched to the limit. All the materials we use today have been specially developed for LM Glasfiber. From the chemical composition of individual fibres to the weaving of mats and the composition of polyester – everything has been tailored for our wind turbine blades and for our processes.
More about our fibre technology

Production process

LM blades are built from the outside in. In fact, we start by painting the blades, before working our way into the structure in this order:

1. mould prepared
2. gelcoat sprayed into the mould – creating the protective surface of the blade
3. glass fibre laid out (supporting layer)
4. bushings installed
5. balsa/foam installed
6. glass fibre laid out over the balsa and bushings
7. vacuum film placed over glass fibre and balsa
8. resin infused
9. vacuum film removed
10. sandwich web installed
11. lightning conductor, etc. installed
12. adhesive applied to edges of the shells and to the webs
13. shells are bonded
14. blade removed from mould and given final finish (cutting and grinding).