Method of manufacturing at least two preforms for moulding a wind turbine blade
The present invention relates to a method and a mould system ( 66 ) for manufacturing at least two preforms for moulding a wind turbine blade. The preforms include at least one preform of a first shape and at least one preform of a second shape. The preform mould structure ( 68 ) has a moulding surface ( 70 ) of variable shape such that the shape of the moulding surface ( 70 ) can be varied at least between a first and a second configuration by using actuators.
1. A method of manufacturing at least two preforms for moulding a wind turbine blade, the at least two preforms including at least one preform having a first shape and at least one preform having a second shape, the second shape being different from the first shape, the method comprising the steps of:
providing a preform mould structure ( 68 ) having a moulding surface ( 70 ) of variable shape such that the shape of the moulding surface ( 70 ) can be varied at least between a first and a second configuration, wherein the first configuration and the second configuration have different curvatures of the moulding surface ( 70 ) in a longitudinal direction of the moulding surface ( 70 );
providing at least one actuator ( 72 ) for changing the shape of the moulding surface ( 70 ) between the first and the second configuration;
moulding at least one preform for an upwind blade half having the first shape on the moulding surface ( 70 ) having the first configuration; and
moulding at least one preform for a downwind blade half having the second shape on the moulding surface ( 70 ) having the second configuration,
wherein the upwind blade half and the downwind blade half correspond to the same wind turbine blade, and
wherein the step of moulding the at least one preform for the upwind blade half and the step of moulding the at least one preform for the downwind blade half are both performed using preform mould structure ( 68 ).
2. The method according to claim 1 , wherein the shape of the moulding surface can be varied across the entire moulding surface.
3. The method according to claim 1 , wherein the first and the second configuration differ in terms of the curvature of the moulding surface ( 70 ).
4. The method according to claim 1 , wherein the first and the second configuration do not differ in terms of the curvature of the moulding surface ( 70 ) in the transverse direction of the moulding surface ( 70 ).
5. The method according to claim 1 , wherein the preform is for use in a main laminate portion of the wind turbine blade.
6. The method according to claim 1 , wherein the moulding surface ( 70 ) can be varied between a concave shape and a convex shape.
7. The method according to claim 1 , wherein the moulding steps comprises laying a fibre material and a binding agent onto the moulding surface ( 70 ).
8. The method according to claim 1 , wherein the moulding surface ( 70 ) is provided on one or more bendable sheets ( 68 ).
9. The method according to claim 8 , wherein the one or more bendable sheets ( 68 ) comprise one or more bendable steel sheets.
10. The method according to claim 1 , wherein the moulding surface ( 70 ) is provided on a single bendable sheet, and wherein one actuator is provided at a front end of the sheet and one actuator is provided at a rear end of the sheet.
11. The method according to claim 1 , wherein the moulding surface ( 70 ) is provided on two or more bendable sheets ( 68 a , 68 b , 68 c ), wherein adjacent sheets are hingedly interconnected along their longitudinal edges ( 84 ), and wherein one actuator ( 72 ) is provided at a front end of each sheet and one actuator ( 72 ) is provided at a rear end of each sheet.
12. The method according to claim 11 , wherein the sheets are hingedly interconnected by one or more elastic strips provided in between adjacent sheets.
13. The method according to claim 1 , the method comprises providing at least three actuators ( 72 ) for changing the shape of the moulding surface between the first and the second configuration.
14. A method of manufacturing a wind turbine blade, the method comprising the steps of:
manufacturing respective preforms for moulding an upwind blade half and a downwind blade half according to the method of claim 1 , wherein the same preform mould is used for at least one preform for the upwind blade half and for the downwind blade half, respectively;
arranging the preforms in respective upwind blade moulds and downwind blade moulds, optionally together with additional material;
infusing resin into the respective upwind blade moulds and downwind blade moulds containing the preforms;
curing or hardening the resin in order to form an upwind blade half and downwind blade half; and
joining the upwind blade half and the downwind blade half to form a wind turbine blade.