EP-4739476-A1 - MOLD ARRANGEMENT

Abstract

Mold arrangement for producing composite preform elements for rotor blades of wind turbine built with preform building materials (7) comprising several fiber mats layers and/or sandwich core materials like balsa or polymer foams fixed by a meltable binder, comprising - a mold (2) with a mold surface (4) defining the shape of the preform element, on which mold the preform building material (7) is arranged, - a flexible, electrically conductive, foil-like heating element (5, 5a, 5b, 5c) arranged or to be arranged at the mold (2) for heating the preform building material (7) from below, - a heating blanket (10) or a further flexible, electrically conductive, foil-like heating element to be arranged on the mold for covering the preform building material and for heating it from above.

Inventors

• Gungor, Sila
• ISCHTSCHUK, LARS
• Mateu, Alfredo Esbri
• Skjoelstrup, Enok Johannes Haahr
• THOMSEN, CLAUS

Assignees

• Siemens Gamesa Renewable Energy A/S

Dates

Publication Date

20260513

Application Date

20240726

Claims (16)

1. 1. Mold arrangement for producing composite preform elements for rotor blades of wind turbine built with preform building materials (7) comprising several fiber mats layers and/or sandwich core materials like balsa or polymer foams fixed by a meltable binder, comprising a mold (2) with a mold surface (4) defining the shape of the preform element, on which mold the preform building material (7) is arranged, a flexible, electrically conductive, foil-like heating element (5, 5a, 5b, 5c) arranged or to be arranged at the mold (2) for heating the preform building material (7) from below, a heating blanket (10) or a further flexible, electrically conductive, foil-like heating element to be arranged on the mold for covering the preform building material and for heating it from above.
2. 2. Mold arrangement according to claim 1, characterized in that the heating element (5, 5a, 5b, 5c) is a polymer foil made of a matrix building polymer (13) with embedded electrically conductive particles (14) .
3. 3. Mold arrangement according to claim 2, characterized in that the matrix building polymer (13) comprises highly conductive particles (14) like carbon black, carbon nanotubes, graphene or MXenes.
4. Mold arrangement according to claim 2 or 3, characterized in that the particles (14) are homogeneously distributed.
5. 5. Mold arrangement according to claim 1, characterized in that the heating element (5, 5a, 5b, 5c) is a foil (16) made of metal or made of metal, carbon or conductive thermoplastic fibers (18) fixed to a carrier, preferably a textile carrier.
6. 6. Mold arrangement according to claim 5, characterized in that the metal or metal fibers are copper, silver, nickel, gold or a combination of at least two of them.
7. 7. Mold arrangement according to one of the claims 2 to 6, characterized in that the foil-like heating element (5, 5a, 5b, 5c) comprises a carrier foil (15) made of a polymer, to which carrier foil (15) the polymer or metal foil (16) or the metal, carbon or conductive thermoplastic fibers (18) fixed to the carrier are attached, or that the metal foil (16) or the metal, carbon fibers or conductive thermoplastic (18) fixed to the carrier are embedded in a polymer carrier matrix (19) .
8. 8. Mold arrangement according to claim 1, characterized in that the heating element is made of electrically conductive wires printed on a carrier, especially a polymer foil or a textile carrier.
9. 9. Mold arrangement according to one of the preceding claims, characterized in that the foil-like heating element (5, 5a, 5b, 5c) has a thickness of less than 3 mm, preferably of less than 1,0 mm and especially less than 0, 5 mm.
10. 10. Mold arrangement according to one of the preceding claims, characterized in that the foil-like heating element (5, 5a, 5b, 5c) has a specific electric conductivity of 100 - 1000 S/m, preferably of 250 - 750 S/m.
11. 11. Mold arrangement according to one of the preceding claims, characterized in that the foil-like heating element (5, 5a, 5b, 5c) is arranged directly on the mold surface (4) by using fixation means.
12. 12. Mold arrangement according to claim 11, characterized in that the fixation means comprise gluing, taping, sta- pling, vacuum fixation or attachment elements, preferably Velcro elements.
13. 13. Mold arrangement according to one of the claims 1 to 10, characterized in that the foil-like heating element (5, 5a, 5b, 5c) is sandwiched between two mold sheets (20, 21) building the mold (2) or is arranged underneath the mold (2) and fixed directly to the bottom side of the mold ( 2 ) .
14. 14. Mold arrangement according to one of the preceding claims, characterized in that it is adapted to produce preform elements for a wind turbine blade.
15. 15. Method for producing a composite preform element using a mold arrangement (1) according to one of the preceding claims, wherein the preform building material (7) arranged at the mold (2) is simultaneously heated by the foil-like heating element (5) from below and by the heating blanket (10) or the foil-like heating element from above .
16. 16. Method according to claim 15, characterized in that the foil-like heating element (5) is placed on the mold surface, whereafter the preform building material is placed on the foil-like heating element (5) , whereafter the heating blanket (10) or a further foil-like heating element is placed on the preform building material (7) , whereafter preferably a vacuum is drawn between the mold (2) respectively the heating element (5) and the heating blanket (10) respectively the further foil-like heating element or a vacuum cover (8) covering or encasing the preform building material (7) , whereafter the heat is applied by the foil-like heating element (5) and the heating blanket (10) or the further heating element (5) .

Description

Description Mold arrangement The invention refers to a mold arrangement for producing a composite preform element built with preform building material comprising several fiber mat layers fixed by a meltable binder . A composite preform element is a prefabricated item which is used for building a pre- fabricated product together with other composite preform elements or other building pieces . An example is the production of a blade for a wind turbine , which blade is usually, among others , built with a number of such composite preform elements , which are used for building the respective blade shell . This example is not restricting, as such preform elements may also be used for building other products . The composite preform element usually comprises several fiber mat layers for example made of glass , carbon or other fiber material , which layers are fixed together with a binder . The binder is usually either already adhered to the fiber mats or is used as a powder spreaded over the layer stack . The binder is activated by heating the preform building material and melts , which allows that the individual fiber mat layers and any optional arranged core material , usually made of balsa or foam placed between the fiber layers in the stack, are sticked together after the binder has cooled down under its speci fic glass transition temperature . The reason for heating the building material is that the heat activates the binder, so that the binder, after reaching a speci fic temperature , melts and glues the layers respectively core elements to consolidate them in a one-piece preform element after it has been cooled down under its speci fic glass transition temperature . This consolidation step may also involve the application of a compacting pressure for example with vacuum, which for example ensures that the preform element building material is pressed together when the binder is activated . Usually, a mold arrangement is used for producing the composite preform element , as such a preform element needs to have a speci fic shape . Such a mold arrangement usually comprises a mold with a mold surface defining the shape of the preform element , on which mold surface the preform building material is arranged . For heating the material in order to activate the binder, the material , which may be arranged in a vacuum bag, is covered with a heating blanket , which is arranged on the mold and extends over the whole building material respectively covers the whole mold, so that heat can be trans ferred from the heating blanket to the building material . This heating blanket allows for heating the building material from the top . To avoid an inhomogeneous heating over the cross section of the material arrangement respectively to avoid an overheating of the top layers , it is known to also apply heat to the building material from underneath . Usually, the mold itsel f comprises heating means like heating pipes through which hot water flows , or electric wires for a resistance heating . These pipes or wires are usually arranged underneath the mold, although in direct contact . But it takes too long to heat up and cool down the mold to the required temperature during the production process . Further, the mold setup is expensive , as the mold itsel f needs to be equipped with the pipe or wire arrangement . The obj ect of the invention is to provide an improved mold arrangement . For addressing the obj ect , the invention refers to a mold arrangement for producing a composite preform element built with preform building material comprising several fiber mat layers fixed by a meltable binder, comprising a mold with a mold surface defining the shape of the preform element , on which mold the preform building material is arranged, a flexible , electrically conductive , foil-like heating element arranged or to be arranged on the mold for heating the preform building material from below, a heating blanket or a further flexible , electrically conductive , foil-like heating element to be arranged at the mold for covering the preform building material and for heating it from above . The inventive mold arrangement comprises a mold with a mold surface , which may for example be trough-like for producing a preform building element for a wind turbine blade . Such a mold has a length of several meters , for example 10 - 12 m, and a width of for example 1 - 4 m, which exemplary figures does not limit the mold to these figures , as the mold can also be shorter or longer or narrower or wider than the above- mentioned figures . The mold surface defines the shape of the preform element . The preform building material is arranged on the mold, wherein the mold surface defines the shape of the finally produced preform element . Vacuum means may be provided to apply a vacuum to the stack for pressing the material against the mold surface and for fixating and shaping it . The mold arrangement further comprises a flexible , electrically conducti