WO2013030467A1

WO2013030467A1 - Fibre application head with comb having flexible tabs

Info

Publication number: WO2013030467A1
Application number: PCT/FR2011/052022
Authority: WO
Inventors: Alexander Hamlyn; Yvan Hardy
Original assignee: Coriolis Composites
Priority date: 2011-09-02
Filing date: 2011-09-02
Publication date: 2013-03-07

Abstract

The present invention relates to a fibre application head for producing parts made of composite materials. The head comprises an application roller (2) for applying a strip formed of one or more fibres to the application surface of a mould, and guidance means (3) for guiding at least one fibre toward said application roller. It also comprises a comb (4) comprising a plurality of flexible tabs (41) capable of coming against said fibre or fibres leaving the guidance means in order to press said fibre or fibres against the application roller.

Description

FIBER APPLICATION HEAD WITH COMB A

FLEXIBLE TONGUES

The present invention relates to a fiber application head for producing parts made of composite materials, more particularly a fiber application head with a flexible lamella comb.

Fiber application machines are known for the contact application on a draping tool, such as a male or female mold, of a wide band formed of one or more continuous flat fibers, of the ribbons type, dry or impregnated with thermosetting or thermoplastic resin, especially carbon fibers, consisting of a multitude of carbon threads or filaments. After application of several layers of superposed strips, the resulting part is subjected to a curing operation, called polymerization, in the case of thermosetting resins, and said consolidation in the case of thermoplastic resins.

These machines conventionally comprise a system for moving a fiber application head, said head comprising an application roller intended to come into contact against the mold for applying the strip, and guiding means for guiding the fiber or fibers. applying on said roll.

In the case of a strip formed of several fibers, the guiding means of these application machines, also called fiber placement machines, make it possible to bring the fibers substantially edge to edge on the roll in the form of a bandaged. As described in particular in the patent document WO2008132299, the guide means conventionally comprise two guide systems arranged staggered in two guide planes approaching each other from upstream to downstream to guide the fibers to the roll under In the form of two layers of fibers, these guiding systems comprise, for example, channels formed at the assembly interface of three plates. These guiding systems are arranged closer to the roll, without contact with the latter. The head further comprises cutting means for individually cutting each fiber, and rerouting means for rerouting each fiber that has just been cut off to be able to stop and resume the application of a tape at any time, as well as to choose the width of the tape.

In the case of the production of parts of complex shapes, and particularly when the head must make trajectories curved to the right or to the left, fibers of the band tend to move laterally. Some fibers applied to the mold can then overlap or be separated from each other. Large overlaps or gaps between adjacent fibers can significantly alter the mechanical properties of the final piece obtained.

Furthermore, depending in particular on the orientation of the head, the positioning of a fiber on the roller following a cutting operation and rerouting may sometimes be imperfect.

The object of the present invention is to propose a solution to overcome the aforementioned drawbacks.

For this purpose, the present invention proposes a fiber application head for the production of composite material parts comprising

- an application roll for applying a strip formed of one or more fibers to the application surface of a mold by contacting said roll against the surface of said mold or against one or more previously applied strips on said surface of said mold, and

guiding means for guiding at least one fiber entering the head towards said application roller,

said head being characterized in that it comprises a comb comprising a plurality of tongues or flexible strips able to come against said one or more fibers coming out of the guide means for putting said fiber or fibers against the application roller.

According to the invention, the head comprises flexible tongues for pressing the fiber or fibers against the application roller, the fiber or fibers leaving the guide means being preferably clamped between the roller and the flexible tongues.

The use of several flexible tongues allows a support of the fiber band over its entire width, regardless of the width thereof, and whatever the possible deformations of the roll application due to the profile of the application surface, thus ensuring precise positioning of the fiber or fibers during draping.

In the case of a strip formed of several fibers, the use of the flexible tabs tongues ensure a good maintenance of the fibers relative to each other, substantially edge to edge, and avoids a lateral deviation of the fibers especially during curved paths of head on the mold.

The flexible tongues further allow each fiber to be guided against the roll, in particular following a cutting operation of a fiber and re-routing of said fiber.

According to one embodiment, said flexible tongues are substantially in contact, and preferably resiliently bearing against the application roller in the absence of fibers leaving the guide means, so that the fiber or fibers coming out of the guide means are clamped between the application roller and said flexible tongues.

According to one embodiment, the head is a so-called fiber placement head for the contact application on a tool of a wide band formed of several continuous flat fibers, said guide means are able to guide a plurality of fibers on the application roll in the form of a band. Said head then advantageously comprises cutting means for cutting, preferably individually, each fiber upstream of the roll with respect to the direction of travel of the fibers, and means for rerouting, arranged upstream of the cutting means, for rerouting each fiber coming from to be cut in order to be able to stop and resume the application of a band at any time, as well as to choose the width of the band. Advantageously, the head further comprises blocking means, arranged upstream of the cutting means, capable of blocking, preferably individually, each fiber that has just been cut.

When a fiber is rerouted, the fiber is guided by one or more tongues to the roller, and passes between the roller and the one or more tabs, elastically outwardly separating said tab or tongues. The flexibility of the tongues and the pinching force exerted by the tongues guarantee a good positioning of the fibers against the roll, while allowing the passage of a fiber during its rerouting.

According to one embodiment, said comb comprises a number of flexible tabs corresponding to the number of fibers, each tab being able to bear against a fiber placed on the application roller. Each tab has a width slightly less than that of a fiber.

As a variant, each tongue bears against several fibers, two adjacent tongues that can bear against the same fiber.

According to another embodiment, the head is provided for the application to the contact on a tool of a strip formed of a single flat fiber in the form of a wide ribbon. In this case, the head comprises guide means adapted to guide a single flat fiber towards the roller.

According to one embodiment, the flexible tongues are covered with a protective film in order to limit their fouling, in particular the fouling between two adjacent tongues, said film allowing a relative elastic displacement between two adjacent flexible tongues, said film covering at least the first main face of each tongue which is oriented towards the roll, preferably at least the two opposite major faces of each lamella. The film is advantageously removable to allow its replacement.

Advantageously, said film is formed of a single-sided adhesive film, glued on the first main faces of the tongues, preferably on the two opposite main faces of the tongues, said film preferably in one part being folded at the edges of the tongues. free end of the tabs.

Alternatively, the protective film is in the form of a sleeve or case which is fitted on the tongues, and optionally heat-shrunk on the latter.

According to one embodiment, the comb is formed of a plate, preferably a metal plate, comprising an upstream assembly portion and a downstream portion, said downstream portion being provided with a plurality of substantially parallel slots extending from an edge of said plate for forming said flexible tongues, said comb being assembled to the head via its assembly portion.

Alternatively the comb is formed of a plurality of individual tabs each fixedly mounted on a base by which the comb is mounted on the head.

To ensure substantially uniform compaction over the entire width of the strip, the head advantageously comprises a compacting roller adapted to adapt to the application surface, in particular to convex and / or concave application surfaces. According to one embodiment, the head comprises a flexible roller, made of a so-called flexible material, elastically deformable, for example of elastomeric material, so as to be deformed by marrying the profile of said surfaces.

According to another embodiment, the roller is a segmented rigid roller, for example metallic, comprising a plurality of independent roller segments mounted side by side on the same axial rod, each segment being movable on said axial rod, perpendicularly to the latter, of independently, and being resiliently biased against the application surface by resilient means, such as expandable bag systems.

The invention will be better understood, and other objects, details, features and advantages will become more clearly apparent from the following detailed explanatory description of a particular presently preferred embodiment of the invention, with reference to the schematic drawings. annexed in which:

- Figure 1 is a schematic partial perspective view of a fiber application head equipped with a comb according to the invention;

FIG. 2 is a partial schematic side view of the application head of FIG. 1 during the lay-up of a strip of fibers on the application surface of a mold;

FIG. 3 is an enlarged perspective view of the comb of the head of FIG. 1;

FIG. 4 is an enlarged side view of the comb of FIG. 3;

- Figure 5 is a perspective view of the comb and its protective film, before the assembly of said film on said comb; and,

FIG. 6 is an enlarged view of the detail D of FIG. FIGS. 1 and 2 partially illustrate a fiber application head 1 according to the invention, provided here for the application on the application surface 91 of a strip formed of several fibers F, for example pre-impregnated with resin . The head 1 comprises, in a manner known per se, an application roller 2, also called a compacting roller, and guiding means 3 for guiding the fibers entering the head in the direction of the roll, to form a fiber band in which the fibers are arranged substantially edge to edge.

The head is for example of the type described in the patent document WO2008132299 cited above. The roll is here a so-called flexible roll, for example an elastomeric material. The guiding means 3 comprise two guiding systems arranged in staggered rows along two guide planes approaching each other from upstream to downstream to guide the fibers towards the roll in two bundles or layers of fibers. These guidance systems comprise, for example, channels formed at the assembly interface of three plates. The fibers of a first ply pass through first channels formed at the assembly interface between a first outer plate 31 and a central plate 32 and the fibers of the second ply pass through second channels formed at the interface of the first web. assembly between the central plate 32 and a second outer plate 33. The downstream edges of the plates from which the fibers come out are arranged close to the roll, without contact with the latter. The head further comprises, in a manner known per se, cutting means for individually cutting each fiber passing through the guiding systems, means of rerouting to reroute individually to the roll each fiber that has just been cut, as well as preferably blocking means for blocking each fiber that has just been cut.

The head is mounted on a displacement system adapted to move the head in at least three directions perpendicular to each other. Said displacement system comprises for example a robot comprising a wrist or poly-articulated arm at the end of which is mounted said application head. The displacement system can be formed by a poly-articulated arm of the standard six-axis robot type, disposed on the ground or mounted on a linear axis or a gantry. The fibers are conveyed from storage means to the head via means of routing. The fiber storage means may comprise a creel in the case of fibers packaged in the form of coils. The conveying means may be formed of flexible tubes, each tube receiving a fiber in its internal passage.

According to the invention, the head is equipped with a comb 4 comprising a plurality of flexible tongues 41 which press against the faces of the fibers F opposite the roller to press said fibers against the roll.

Referring to Figures 3 to 6, the comb 4 comprises a base 42 by which the comb is mounted on the head, said base carrying a plurality of flexible tongues 41. The comb is formed of a substantially rectangular plate 40, preferably metal , comprising two lateral edges, an upstream edge and a downstream edge. The plate comprises an upstream portion forming the base 42 and a downstream portion 43, said downstream portion being provided with a plurality of slots 44, substantially parallel to each other and to the lateral edges of the plate, extending from the front edge of said plate, to form said tongues.

The comb is flat-mounted by its base against the outer surface of the second outer plate 33 so that its tongues extend between the guide systems and the roller. The tongues are substantially tangentially and resiliently supported by their free end portion against the cylindrical surface of the roll, upstream of the contact generatrix of the roller with the mold application surface.

For its mounting, the base 42 of the comb is placed between the outer surface of the second plate 33 and a counterplate 5, fixed to said second plate by means of screws (not shown), passing through holes 51 of the counter plate and holes (not shown) of the base of the comb, and screwed into tapped holes of the second plate 33.

As seen in Figure 4, before mounting, the flexible tongues are slightly bent. The bending lines are schematically shown as 45 in FIG. 5. The plate with its concavity facing the roll is mounted on the head. Once mounted, the tongues are resiliently bearing against the roller, and the plate has a substantially flat shape. During draping, the fibers emerging from the guiding systems are thus clamped between the flexible tongues and the surface of the roll, upstream of the generatrix of contact of the roll with the mold.

In the present embodiment, the head is provided for the application of strips of eight fibers. The comb comprises eight flexible tongues, each tongue has a width slightly less than that of a fiber and is intended to bear against a fiber.

A single-sided adhesive film 6, for example a polyethylene film, is adhered to the two main faces of the comb, said film being folded at the free end edges of the tongues. The film has a deformation capacity, elastic or not, which is sufficient to allow relative elastic displacement between two adjacent tongues. This so-called protective film makes it possible to limit the clogging of the comb with the resin, in particular between two adjacent tongues.

Although the invention has been described in connection with a particular embodiment, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention.

Claims

Fiber application head (1) for making composite material parts comprising an application roll (2) for applying a web of one or more fibers to the application surface a mold, and guiding means (3) for guiding at least one fiber towards said application roller, characterized in that it comprises a comb (4) comprising a plurality of flexible tongues (41) adapted to come against said fiber or fibers leaving the guide means for putting said fiber or fibers against the application roller.

2. Applicator head according to claim 1, characterized in that said flexible tongues (41) are resiliently bearing against the roller (2) of application in the absence of fibers leaving the guide means (3).

3. Fiber application head according to claim 1 or 2, characterized in that said guide means (3) are adapted to guide a plurality of fibers (F) on the application roll in the form of a strip .

4. Fiber application head according to claim 3, characterized in that said comb comprises a number of flexible tabs (41) corresponding to the number of fibers (F), each tab being able to bear against a fiber placed on the application roller (3).

5. Fiber application head according to one of claims 1 to 4, characterized in that the flexible tongues are covered with a film (6) of protection to limit their fouling, said film covering at least the first face main of each tab which is oriented towards the application roller.

6. Fiber application head according to claim 5, characterized in that said film (6) is formed of a single-sided adhesive film, glued on the first main faces of the tongues.

7. Fiber application head according to one of claims 1 to 6 characterized in that the comb (4) is formed of a plate (40) comprising an upstream portion (42) assembly and a downstream portion ( 43), said downstream portion being provided with a plurality of slots (44) for forming said flexible tongues (41).