Manufacturing Technologies for Turbine Power Blades - Hybrid Anisotropic Materials for Wind Power Turbine Blades - page 93

The.prepreg.technology.offers.some.advantages,.such.as.it.is.easy.to.con-
trol. and. to. obtain. constant. material. properties,. and. a. higher. iber. content.
gives. higher. speciic. stiffness. and. strength. to. the. material. that. leads. to.
lighter.blades..Also.a.clean.process.is.obtained,.which.leads.to.a.better.work-
ing. environment. where. fewer. requirements. are. needed. for. the. workshop.
ventilation.systems..This.results.in.cost.savings.on.smaller.ventilation.sys-
tems.and.the.energy.needed.in.heating.
Vestas.Wind.Systems,.a.Varde,.Denmark,.wind.turbine.manufacturer,.uses.
the.prepreg.technology.for.its.blade.production..Vestas.has.used.glass/epoxy.
prepreg.technology.for.many.years,.and.have.now.introduced.carbon.ibers.
in.its.45-m-long.blades. 8,9

4.5 ResinInfusionTechnology

Resin.infusion.technology.consists.of.placing.dry.ibers.in.a.mold,.encapsulating.
and.sealing.off.the.iber.package,.injecting.the.liquid.resin.into.the.iber.package,.
and.curing.the.package..Since.the.1990s,.the.process.equipment.has.been.inten-
sively.developed,.and.resin.infusion.technology.is.now.a.widely.used.industrial.
process..The.inal.product.has.not.had.a.dry.surface,.but.is.wetted.by.resins.
Most.developments.have.concentrated.on.this.technique.and.have.tackled.
it.from.many.sides:

•. Fiber.sizing.with.improved.wetability.to.facilitate.complete.wetting.
without.manipulating.the.roving.iber.fabrics.with.special.architec-
ture.to.control.low.pattern.of.the.resin.
•. Resin. with. low. viscosity. to. improve. wetability. and. lower. the. pro-
cess.time.for.large.components;.resin.that.does.not.release.volatiles.
under.vacuum.
•. Accessories. that. help. control. a. resin. low. pattern. over. large. areas.
and. ensure. complete. wetting. of. thick. laminates;. resin. distribution.
mesh,.special.sandwich.core,.etc.
•. Equipment.for.continuous.mixing.of.resin.without.introducing.air
•. Design.of.molds.(placement.of.inlet.and.outlet.for.resin,.sealing.around.
the.edge).to.control.resin.low.to.prevent.entrapped.area.with.dry.ibers.
•. Sensors.for.monitoring.the.low.front.
•. Computer. models. for. the. predicting. and. optimization. of. the. low.
pattern.for.a.given.component.

LM. Glasiber. in. Demark. is. one. of. the. turbine. blade. manufacturers. that.
uses.resin.infusion.technology,.and.it.has.proved.to.be.successful.in.the.com-
pany's.most.recently.developed.61.5-m-long.blade. 10