TREATMENT OF A FIBRE REINFORCED COMPOSITE ELEMENT

Abstract

The disclosure relates to a method of manufacturing a fibre reinforced composite, wherein the surface of the fibre reinforced composite modified by using a laser radiation. In particular, the pre-treatment is performed before a bonding process. Time-consuming and dust generating grinding of the surface can be avoided.

Claims

1-23. (canceled)

24. A method of pre-treating a fiber reinforced composite element, the method comprising: providing a plurality of lasers including a first laser and a second laser, wherein the first laser is configured to emit a first laser beam in a first laser direction and the second laser is configured to emit a second laser beam in a second laser direction, and wherein the first laser and the second laser are separated along a primary direction and located along a line non-parallel with the primary direction; orienting the fiber reinforced composite element relative to the plurality of lasers such that the first laser is at a first laser distance along the first laser direction from a first surface of the fiber reinforced composite element and the second laser is at a second laser distance along the second laser direction from the first surface of the fiber reinforced composite element; emitting the first laser beam in the first laser direction from the first laser; emitting the second laser beam in the second laser direction from the second laser; and while emitting the first laser beam and the second laser beam, moving the fiber reinforced composite element relative to the first laser and the second laser in the primary direction.

25. The method of claim 24, wherein the fiber reinforced composite element is a first fiber reinforced composite element, the method further comprising: pre-treating the first fiber reinforced composite element; and subsequently incorporating the first fiber reinforced composite element in a fiber reinforced composite structure.

26. Method according to claim 25, wherein incorporating the first fiber reinforced composite element comprises applying a bonding agent to a first surface of the first fiber reinforced composite element.

27. The method of claim 26, further comprising: providing a second fiber reinforced composite element; pre-treating the second fiber reinforced composite element; and subsequently incorporating the second fiber reinforced composite element in the fiber reinforced composite structure.

28. The method of claim 27, wherein incorporating the first fiber reinforced composite element comprises joining the first surface of the first fiber reinforced composite element and a first surface of the second fiber reinforced composite element and applying a bonding agent between the first surface of the first fiber reinforced composite element and the first surface of the second fiber reinforced composite element.

29. The method of claim 24, wherein the primary direction is parallel to the first surface.

30. The method of claim 24, wherein the fiber reinforced composite element is oriented relative to the first laser such that the first laser direction is substantially perpendicular to the first surface.

31. The method of claim 24, wherein the fiber reinforced composite element is a pultruded element.

32. The method of claim 24, wherein the fiber reinforced composite element comprises at least one of carbon fiber or glass fiber.

33. The method of claim 24, wherein the fiber reinforced composite element comprises at least one of epoxy, polyester, or vinyl ester resin.

34. The method of claim 24, wherein fibers of the fiber reinforced composite element are substantially oriented along the primary direction.

35. The method of claim 24, wherein the first laser and the first laser distance are configured such that the first surface of the fiber reinforced composite element is modified by the first laser beam hitting the first surface.

36. The method of claim 24, wherein the first surface of the fiber reinforced composite element is subjected with a power density of more than 1 MW/cm.sup.2 and less than 100 MW/cm.sup.2.

37. The method of claim 33, further comprising pulsing laser radiation onto the fiber reinforced composite element, wherein the power density is controlled by adjusting at least one of a pulse width or a repetition rate of the pulsed laser radiation.

38. The method of claim 24, wherein the first surface of the fiber reinforced composite element is subjected with an energy of more than 80 J/cm.sup.2 and less than 1000 J/cm.sup.2.

39. The method of claim 24, wherein the first laser beam has a wavelength between about 400 nanometers (nm) and 500 nm.

40. The method of claim 24, wherein the first laser direction and the second laser direction are parallel.

41. The method of claim 24, wherein the fiber reinforced composite structure is a wind turbine blade or a part thereof.

42. An arrangement for pre-treating a fiber reinforced composite element, the arrangement comprising: a plurality of lasers comprising a first laser and a second laser, the first laser adapted to emit a first laser beam in a first laser direction, the second laser adapted to emit a second laser beam in a second laser direction, the arrangement adapted to be oriented relative to the fiber reinforced composite element such that the first laser is at a first laser distance along the first laser direction from a first surface of the fiber reinforced composite element and the second laser is at a second laser distance along the second laser direction from the first surface of the fiber reinforced composite element, while emitting the first laser beam and the second laser beam, the arrangement is adapted to move the first laser and the second laser relative to the fiber reinforced composite element along a primary direction, wherein the first laser and the second laser are separated along the primary direction and located along a line non-parallel with the primary direction.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0078] Embodiments of the disclosure will be described in more detail in the following with regard to the accompanying figures. The figures show one way of implementing the present disclosure and are not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

[0079] FIG. 1 is schematic illustration of a fibre reinforced composite element being pre-treated with laser radiation,

[0080] FIG. 2 is a schematic illustration of a laser module,

[0081] FIG. 3 is a schematic illustration of a pultruded fibre reinforced profile being pre-treated with laser radiation by using an array of laser modules,

[0082] FIG. 4 is a picture of an exemplary pre-treated surface,

[0083] FIG. 5 is a picture of an exemplary surface with a pre-treated area, and resin applied to the surface, and

[0084] FIG. 6 shows exemplary depth profiles of a surface being pre-treated with laser radiation of varying power density.

DETAILED DESCRIPTION

[0085] FIG. 1 is schematic illustration of a fibre reinforced composite element 1 being pre-treated with laser radiation.

[0086] The fibre reinforced composite element 1 may be embodied as a pultruded carbon profile, wherein the thickness is reduced towards at least one edge, resulting in a very shallow angle.

[0087] The fibre reinforced composite element 1 may be pre-treated before the component is bonded, e.g. in an infusion bonding process, to another component.

[0088] The surface 2 of the fibre reinforced composite element may be pre-treated with laser radiation.

[0089] In the illustrated example, a single laser 3 is moved so that the laser beam 4, which is focused onto the surface, moves over the surface 2 in a meandering fashion. Preferably, the laser 3 is moved parallel to the surface 2 in order to ensure a constant distance from the surface 2. The laser beam 4 is aligned substantially perpendicular to the surface 2.

[0090] The laser 3 forms a multitude of grooves on the surface, which may overlap or border directly on each other in order to pre-treat the entire desired surface area. The result may be a peeled surface region.

[0091] Since generation of dust particles may be reduced or avoided, the fibre reinforced composite element can be used directly for further manufacturing steps, in particular for an infusion bonding process.

[0092] For pre-treating larger elements, the process may be scaled up. For scaling up the process, an array of lasers, e.g. LDs, may be used.

[0093] Lasers with a maximum power output of more than 2 W, such as more than 10 W, may be suitable to emit a focused beam onto the surface having a power density of more than 2 MW/cm.sup.2.

[0094] FIG. 2 schematically illustrates a laser module 5 which comprises a multitude of lasers which are arranged on a support 7, e.g. a circuit board.

[0095] As illustrated in FIG. 3, which is a schematic illustration of a fibre reinforced composite element, such as a pultruded fibre reinforced composite element 8 being pre-treated with laser radiation by using an array of laser modules, a multitude of laser modules 5a-5n may be used, e.g. to pre-treat a large area in a short time.

[0096] In the illustrated example, the laser modules 5a-5n and the lasers themselves form an array, wherein modules and the lasers are arranged in rows and columns.

[0097] According to this embodiment, the lasers of one row of laser modules are arranged offset to the lasers of the adjacent row (e.g. 5b to 5a). Preferably, the offset distance is 0,5 to 5 of the spot size of the focused beam on the surface. Thereby, it is possible to pre-treat the entire surface of the fibre reinforced composite element in one process, i.e. by moving the fibre reinforced composite element through the arrangement of lasers once. This can also or in addition be achieved by inclining the fibre reinforced composite element with respect to the LD array in an acute angle.

[0098] FIG. 4 is a picture of a pre-treated surface. The surface comprises a multitude of essentially parallel arranged grooves with a width between 0.1 and 1.5 mm and/or a maximum depth between 0.05 and 1 mm, which are generated by the laser radiation.

[0099] The surface is “brushed” by the laser radiation and has the appearance of a brushed metal surface.

[0100] FIG. 5 is a picture of surface with a pre-treated area, wherein a resin is applied to the surface, i.e. onto the treated as well as onto an untreated area.

[0101] On the untreated area, the resin forms a drop with a contact angle of more than 40°. In contrast, the resin forms a shallow wetted area on the rectangular pre-treated region, with a much smaller contact angle. As seen the treatment causes a much better wetting of the element by the resin, compared to an untreated element.

[0102] FIG. 6 shows exemplary depth profiles of a surface being pre-treated with laser radiation of varying power density.

[0103] In area A, the surface has been exposed to a pulsed laser radiation with a power density of less than 2 MW/cm.sup.2 and with an energy of 115 J/cm.sup.2. Surface area A is slightly roughened.

[0104] Surface area B has been treated with by a pulsed laser radiation with a power density of approx. 3 MW/cm.sup.2, resulting in an energy of 160 J/cm.sup.2. This results in a rougher surface in comparison to area A.

[0105] As shown in area C, a pulsed laser radiation with a power density of approx. 8.5 MW/cm.sup.2, resulting in an energy of 220 J/cm.sup.2, generates grooves with a maximum depth of more than 0.5 mm.

[0106] The disclosure has been described with reference to preferred embodiments. However, the scope of the invention is not limited to the illustrated embodiments, and alterations and modifications can be carried out without deviating from the scope of the invention.

[0107] Exemplary embodiments of the present disclosure are provided in the following items:

[0108] 1. A method of pre-treating a fibre reinforced composite element, the method comprising: [0109] providing a first laser configured to emit a first laser beam in a first laser direction; [0110] orienting the fibre reinforced composite element relative to the first laser such that the first laser is at a first laser distance along the first laser direction from a first surface of the fibre reinforced composite element; [0111] emitting the first laser beam in the first laser direction from the first laser; [0112] while emitting the first laser beam moving the fibre reinforced composite element relative to the first laser in a primary direction.

[0113] 2. Method according to item 1, wherein the fibre reinforced composite element is pre-treated before incorporating the fibre reinforced composite element in a fibre reinforced composite structure.

[0114] 3. Method according to any of the preceding items, wherein the primary direction is parallel to the first surface.

[0115] 4. Method according to any of the preceding items, wherein the fibre reinforced composite element is oriented relative to the first laser such that the first laser direction is substantially perpendicular to the first surface.

[0116] 5. Method according to any of the preceding items, wherein the fibre reinforced composite element is a pultruded element.

[0117] 6. Method according to any of the preceding items, wherein the fibre reinforced composite element comprises carbon fibre and/or glass fibre.

[0118] 7. Method according to any of the preceding items, wherein the fibre reinforced composite element comprises a resin, e.g. epoxy, polyester, or vinyl ester resin.

[0119] 8. Method according to any of the preceding items, wherein fibres of the fibre reinforced composite element is substantially oriented along the primary direction.

[0120] 9. Method according to any of the preceding items, wherein the first laser and the first laser distance are configured such that the first surface of the fibre reinforced composite element is modified, e.g. structured, roughened, cleaned and/or chemically activated, by the first laser beam hitting the first surface.

[0121] 10. Method according to any of the preceding items, wherein the first surface of the fibre reinforced composite element is subjected with a power density of more than 1 MW/cm2, such as more than 10 MW/cm2, such as more than 15 MW/cm2 and/or wherein the first surface of the fibre reinforced composite element is subjected with a power density of less than 100 MW/cm2, such as less than 60 MW/cm2.

[0122] 11. Method according to any of the preceding items, wherein the first surface of the fibre reinforced composite element is subjected with an energy of more than 80 J/cm2, such as more than 100 J/cm2, such as more than 200 J/cm2 and/or wherein the first surface of the fibre reinforced composite element is subjected with an energy of less than 1000 J/cm2.

[0123] 12. Method according to any of the preceding items, wherein the first laser beam has a wavelength between 400 and 500 nm.

[0124] 13. Method according to any of the preceding items, wherein the laser radiation is pulsed, and wherein the power density is controlled by adjusting a pulse width and/or repetition rate of the pulsed laser radiation.

[0125] 14. Method according to any of the preceding items comprising providing a plurality of lasers including the first laser and a second laser, wherein the second laser is configured to emit a second laser beam in a second laser direction, and wherein orienting the fibre reinforced composite element comprise orienting the fibre reinforced composite element relative to the second laser such that the second laser is at a second laser distance along the second laser direction from the first surface of the fibre reinforced composite element, and the method comprises emitting the second laser beam in the second laser direction from the second laser.

[0126] 15. Method according to item 14, wherein the first laser direction and the second laser direction are parallel.

[0127] 16. Method according to any of items 14-15, wherein the first laser and the second laser are separated along the primary direction and located along a line non-parallel with the primary direction.

[0128] 17. A method of manufacturing a fibre reinforced composite structure, the method comprising: [0129] providing a first fibre reinforced composite element; [0130] pre-treating the first fibre reinforced composite element according to any of the preceding items; [0131] after pre-treating the first fibre reinforced composite element incorporating the first fibre reinforced composite element in the fibre reinforced composite structure.

[0132] 18. Method according to item 17, wherein incorporating the first fibre reinforced composite element comprises applying a bonding agent to the first surface of the first fibre reinforced composite element.

[0133] 19. Method according to any of items 17 or 18 comprising providing a second fibre reinforced composite element.

[0134] 20. Method according to item 19 comprising pre-treating the second fibre reinforced composite element according to any of the preceding items.

[0135] 21. Method according to any of items 17 or 18, wherein incorporating the first fibre reinforced composite element comprises joining the first surface of the first fibre reinforced composite element and the first surface of the second fibre reinforced composite element and applying a bonding agent between the first surface of the first fibre reinforced composite element and the first surface of the second fibre reinforced composite element.

[0136] 22. Method according to any of the preceding items, wherein the fibre reinforced composite structure is a wind turbine blade or a part thereof

[0137] 23. A fibre reinforced composite structure, e.g. a fibre reinforced composite structure of a wind turbine blade, being manufactured using a method according to any of items 17-22.

[0138] 24. A fibre reinforced composite element comprising at least one surface, which is pre-treated with laser radiation by the method according to any of items 1 to 16.

[0139] 25. Arrangement for pre-treating a fibre reinforced composite element, the arrangement comprising a plurality of lasers including a first laser and a second laser, wherein the first laser is adapted to emit a first laser beam in a first laser direction, and the second laser is adapted to emit a second laser beam in a second laser direction,

[0140] the arrangement being adapted to be oriented relative to the fibre reinforced composite element such that the first laser is at a first laser distance along the first laser direction from a first surface of the fibre reinforced composite element and such that the second laser is at a second laser distance along the second laser direction from the first surface of the fibre reinforced composite element,

[0141] while emitting the first laser beam and the second laser beam the arrangement is adapted to move relative to the fibre reinforced composite element along a primary direction,

[0142] wherein the first laser and the second laser are separated along the primary direction and located along a line non-parallel with the primary direction.