High efficiency, high speed manufacturing Thick (>75mm) UD glass/ resin requires slow room temperature cures, to maintain control of exotherm heat. Thus the blade shells are in the moulds for 2 days. This is then followed by several sequential root end machining processes on specialist machines. With bamboo, the resin is only ever in thin layers, and raised temperature rapid cure processes can be used, with the root studs infused in as part of the process. There are no postmoulding process machining steps. The key to achieving high quality and rapid throughput is well designed manufacturing processes that keep the materials flowing smoothly and enable small teams of skilled craftsmen to keep moving and working easily in a smooth rhythm. It is like choreographing a dance.
Process improvements Wood composite
Infused wood carbon
Open moulds Clean moulds Gel coat Cure Outer glasscloth Cure Wood veneers Vacuum Cure Peel and trim Inner glasscloth Cure Trim Joining adhesive Place webs Join moulds Cure Drill stud holes Place studs Cure
Open moulds Clean moulds Gel coat Cure Place all dry material Vacuum Infuse Cure Peel and trim Joining adhesive Place webs Join moulds Cure
20 steps 2 days
13 steps 1 day …. And 12 hours is possible
Old blade:- 23.5m, 3.2 tonnes This blade:- 25m, 2.2 tonnes
The blade twists and tapers
The blade is curved, so that it is straight when under load
The bamboo shell tapers, but remains wide half way along the blade, as the blade quickly becomes thin.
Wood lay-up
Root Fixings built in for infusion
40m Blade Infusing
40m Web placement
Mould closure
This is at 30% overload.
And at the end of its life - you can make furniture out of it!
Cellulose Fibrils:Understanding the Science Geometry & Chemistry
Chemical composition of wood
Fibril geometry
Fibrous structure of wood
Cellulose molecular structure
Effect of dryness on strength
Creating a high tech material from bamboo Splitting bamboo stems into narrow strips and then separating the outer high fibre density “skin” layer gives the starting point. Laminating these strips into planks gives a statistical averaging effect. Drying down to 3-4% moisture content achieves best properties. Epoxy is a complete vapour barrier. Coating en epoxy during the manufacturing process seals in and guarantees the high tech properties for life. Design strengths are (mean - 3 standard deviations).
The bonus of bamboo Utterly sustainable - no irrigation, fertiliser, pesticides or heavy machinery and over 5000 years of continuous annual cropping so far…. Low intrinsic energy. A carbon sequestration process itself. Vast resource globally (380GW blade capacity possible annually from the Chinese Moso bamboo resource alone).
Material Challenges Understand the nature of cellulosic materials and protect against moisture. Understand the variability of natural materials and process accordingly. Develop high tech material supply chains based on sustainable forestry. Develop bamboo fibre extraction and processing technology. Develop lower cost variants of epoxy.
