Method and machine for applying a band of fibers on convex surfaces and/or with edges
Embodiments of the invention relate to a fiber application method and a fiber application machine for producing parts in composite material, such as for the application of a band of fibers on convex surfaces and/or with edges. The machine comprises a fiber application head and a moving system for moving the application head. The application head comprises a compacting system including a compacting roller intended to come in contact against the application surface to apply the band, and a compacting member placed downstream from the compacting roller and exhibiting a substantially planar contact surface, said compacting member being capable of being pressed by its contact surface, against an application surface, substantially on the entire width of a band, by at least one contact line.
1. A method for applying a band formed of several fibers on an application surface comprising a first substantially planar surface and a second substantially planar surface connected by an edge or a rounded surface, or on a convex application surface, application of the band carried out by a fiber application head comprising a compacting system including a compacting roller, the method comprising:
applying the compacting roller against the application surface and moving the fiber application head to apply a band of fibers on the application surface;
applying, against the band of fibers applied on the application surface, a compacting member of the compacting system, arranged downstream from the compacting roller with respect to a progress direction of the fiber application head, the compacting member being substantially in contact with all the fibers of the band by at least one contact line; and
pivoting the fiber application head around the edge, around the rounded surface or around the convex application surface, such that the compacting member remains in contact with the band to compact the band by at least one contact line, substantially without sliding between the compacting member and the application surface.
2. The method according to claim 1 , wherein the application surface comprises a first substantially planar surface and a second substantially planar surface connected by an edge, and wherein the method comprises:
applying the compacting roller against the first surface by at least one contact line, and moving the fiber application head to apply a band of fibers on the first surface, in a first direction forming an angle α 1 with the edge;
moving the fiber application head in the first direction, tangentially to the first surface, to bring the compacting roller substantially beyond the edge, and applying the compacting member against the band applied on the first surface;
pivoting the fiber application head around the edge, such that the compacting member remains in contact with the band by at least one contact line, the pivoting carried out until the compacting roller contacts the second surface by at least one contact line substantially corresponding to a width of the band; and
separating the compacting member from the application surface so that the compacting member is no longer in contact with the application surface, and moving the fiber application head to apply the band on the second surface, in a second direction forming an angle α2 with the edge, substantially equal to 180-α1.
3. The method according to claim 2 , wherein the angle α 1 is between 10° and 80° .
4. The method according to claim 1 , wherein the application surface comprises a first substantially planar surface and a second substantially planar surface connected by a rounded surface, the method comprising
applying the compacting roller against the first surface by at least one contact line and moving the fiber application head to apply a band of fibers on the first surface, in a first direction forming an angle al with a first junction line between the first surface and the rounded surface;
moving the fiber application head in the first direction, tangentially to the first surface, to bring the compacting roller beyond the first junction line, and applying the compacting member against the band applied on the first surface;
pivoting the fiber application head around the rounded surface, such that the member remains in contact with the band by at least one contact line, until the compacting roller contacts the second surface by at least one contact line; and
separating the compacting member from the application surface so that the compacting member is no longer in contact with the application surface, and moving the fiber application head contacting the second surface by the compacting roller by at least one contact line to apply the band on the second surface, in a direction forming an angle α 2 , substantially equal to 180-α 1 , with the second junction line between the rounded surface and the second surface.
5. The method according to claim 4 , wherein after applying the compacting member against the band applied on the first surface, the method comprises:
pivoting the fiber application head around the rounded surface until contacting the compacting roller against the application surface; and
if the compacting roller is in contact on at least one contact point with the rounded surface at the end of the pivoting, moving the fiber application head tangentially to the rounded surface to the contact point, in a direction forming an angle α1 with a generatrix line of the rounded surface passing by the contact point, then pivoting the fiber application head around the rounded surface, this moving and pivoting being repeated until contacting the compacting roller against the second surface by at least one contact line.
6. The method according to claim 4 , wherein after applying the compacting member against the band applied on the first surface, the method comprises:
pivoting the fiber application head around the rounded surface; and
before the compacting roller comes into contact on at least one contact point with the rounded surface, moving the fiber application head tangentially to the rounded surface to the contact point, in a direction forming an angle α1 with a generatrix line of the rounded surface passing by the contact point, then pivoting the fiber application head around the rounded surface, this moving and pivoting being repeated until contacting the compacting roller against the second surface by at least one contact line.
7. The method according to claim 1 , wherein the application surface is convex, and the method comprises:
applying the compacting roller against the convex application surface by at least one contact point;
moving the fiber application head tangentially to the convex application surface to the contact point in a direction forming an angle α 1 with a generatrix line of the convex surface passing by the contact point to bring the compacting roller beyond the generatrix line; and
pivoting the fiber application head, pressed against the convex application surface by its compacting member, around the convex application surface, the pivoting being carried out such that the member remains in contact with the band by at least one contact line.
8. The method according to claim 7 , wherein after moving the fiber application head tangentially to the convex application surface to the contact point, the method comprises:
pivoting around the convex application surface, the fiber application head pressed against the convex application surface by its compacting member, until contacting the compacting roller against the convex application surface; and
repeating the moving and pivoting one or more times.
9. The method according to claim 7 , wherein after moving the fiber application head tangentially to the convex application surface to the contact point, the method comprises:
pivoting around the convex application surface, the fiber application head pressed against the convex application surface by its compacting member; and
before contacting the compacting roller against the convex application surface, repeating the moving and pivoting one or more times.