PL230650B1 - Mould for thermal forming of a sandwich panel and the related method - Google Patents

Description

Description of the invention

The present invention relates to a mold for making a composite panel, the composite panel having a core and at least one facing applied to a lower face of the core and to at least one side face, and the mold comprising:

- the first album;

- a second plate, slidable with respect to the first plate along the axis of translation, between an open position and a closed position; and

- at least one closing guide fixed with respect to the first panel and projecting towards the second panel simultaneously defining an interior space intended to form the panel, a guide including a tilted face for folding up the lower cladding on the side face of the core.

The composite panel is particularly intended for the production of a structural part of a motor vehicle, such as a folding table or a boot loading floor.

A method of manufacturing a panel for equipping motor vehicles is already known from the prior art, for example from US Patent No. US2006 / 0141206 or French No. FR 2 918 923, which include the step of assembling a honeycomb core made of cardboard or paper between two composite cladding.

Thus, a composite panel of the sandwich type is formed. This panel is generally given a coating, most often of the pile or stitching type of fleece. Such panels are lightweight and durable, which is desirable in motor vehicles. However, it is preferable for such panels that, for aesthetic reasons as well as to maximize the possibility of placing them on a small substrate, they have side faces at angles as close as possible to 90 °. This is especially true when the part is a boot floor placed on compensating inserts along the side trim of the boot.

Traditional one-step manufacturing methods do not readily achieve this type of right angle since the core is crushed at the edges when the composite facings are stretched and folded to cover the side faces.

To overcome this problem, it is known to use a manufacturing method that includes the step of applying resin to both facings made of glass fibers placed on both sides of the cardboard core. The resin is applied by spraying using a robotic device, which makes it possible to adjust the amount of resin applied to the edges of the parts and eliminate the problem of crushing the edges of the core. Nevertheless, these parts, with regard to the material called "Baypreg", prove to be expensive to manufacture due to the long time cycle and the increased amount of material consumed.

However, it is desirable for the manufacturer to maintain a one-step production method in order to minimize production times.

Thus, the invention aims to provide equipment for the production of composite panels, in which the side faces have angles close to 90 °, which allows one-step production of composite panels at lower cost and with optimal quality.

The invention therefore relates to a mold for the production of a composite panel, the composite panel comprising a core and at least one bottom face applied to the bottom face of the core and to at least one side face, the mold comprising:

- the first album;

- a second plate, slidable with respect to the first plate in their direction of travel (Z-Z), between an open position and a closed position; and

- at least one closing guide fixed with respect to the first panel and projecting towards the second panel defining an interior space for forming the panel at the same time, the guide including a bevelled face for folding up the lower cladding on the side face of the core;

characterized in that it further comprises an intermediate plate mounted on the first plate in the inner space, the intermediate plate being slidable relative to the first plate in their direction of travel (ZZ), with at least one spring arranged between the first plate and the intermediate plate with the direction of travel of the plates, the one or each spring resisting the sliding movement of the intermediate plate towards the first plate.

PL 230 650 B1

Preferably, the intermediate plate is flush with the base of one or each track in the closed position. The tilted face of the or each track has a perpendicular angle with the axis of translation (Z-Z) comprised between 80 ° and 90 °, the tilted face being oriented towards the intermediate plate. In the open position, the guide protrudes beyond the intermediate plate. One or each track has a sharp edge oriented towards the other plate, the sharp edge adapted to come into contact with the other plate in the closed position and cut the lower cladding. The mold preferably comprises at least one removable compensation insert positioned between the first plate and the intermediate plate. It preferably also comprises means for applying shock-absorbing back pressure to the second plate in the closed position.

The invention also relates to a method for manufacturing a composite panel using the above mold, which comprises the following steps:

- introduction of the form described above;

- feeding of the core and lower cladding placed across from the lower face of the core;

- sliding the second plate towards the closed position;

- locking the lower cladding to the lower face through an intermediate plate, the core being positioned in the inner space of the mold;

cutting the core with a guide to form a side face of the core; and

- bringing the tilted curving face of the guide into contact with the bottom cladding in order to apply the bottom cladding to the side face.

Advantageously, in the method according to the invention, the intermediate plate exerts pressure on the composite panel below a threshold crushing pressure on the core when the first plate is moved between the intermediate and the closed positions.

According to one particular embodiment, the method of the invention comprises one or more of the following features:

the method comprises the step of plastically deforming the core in a closed position;

the method comprises the step of cutting the lower cladding and the upper cladding with the sharp edge of the one or each track.

The invention will be better understood by the following description, introduced only as an example, and made with reference to the accompanying drawing figures, in which:

FIG. 1 is a cross-sectional view of a mold according to the invention in an open position;

FIG. 2 is a cross-sectional view of the mold of FIG. 1 in an intermediate position;

FIG. 3 is a sectional view of FIG. 1 and 2 in closed position.

A mold 2 according to the invention is shown in FIG. 1 in open position.

The mold 2 is intended to produce the composite panel 4 according to the method in one molding step. In FIG. 1 to 3 shows the composite panel 4 inserted into the mold 2.

The composite panel 4 comprises a core 6 having a lower face 7A and an upper face 7B. The panel also includes a lower face 10A located on the lower face 7A and an upper face 10B located on the upper face 7B.

After panel 4 is manufactured, the core 6 has at least one side of the face 8 covered with a lower facing 10A. The angle formed on the lower face between the side face 8 and the lower face 7A is between 80 ° and 95 °, preferably between 87 ° and 90 °.

The core 6 is made of a cellular structure or a honeycomb structure.

Thus, the core 6 has a plurality of faces perpendicular to the lower face 7A and the upper face 7B, forming cells.

Each cell extends across the core from the lower cladding 10A at one end and across the core from the upper cladding 10B at the other end. Cells, for example, define polygonal, in particular hexagonal, meshes.

The core 6 preferably has a thickness greater than 2 mm and for example comprised between 2 mm and 100 mm, in particular between 5 mm and 30 mm.

The core 6 is preferably made of a lightweight material such as paper or cardboard. Thus, the composite panel 4 has sufficient lightness due to the low specific weight of the core 6.

PL 230 650 B1

The core 6 is adapted not to deform plastically between the lower face 10A and the upper face 10B below the threshold crushing pressure under the influence of the transverse pressures applied. The threshold compression pressure is, for example, 500 kPa.

Each cladding 10A, 10B preferably has a thickness less than the core 6. More generally, the thickness of each cladding 10A, 10B is less than 3mm, and in particular is between 0.6mm and 2mm.

Preferably, the facings 10A, 10B are made of a material of the type referred to as "Neomold". This composite material has mineral fibers, for example glass fibers, and a matrix made of a heat-sealable polymer having a melting point, for example, comprised between 200 ° C and 270 ° C. The polymer matrix is preferably made of a thermoplastic impregnated polyester.

Form 2 comprises a first plate 12 and a second plate 14 moveable relative to the first plate 12 in the direction of travel Z-Z.

For example, the Z-Z travel direction is a vertical direction, with the first plate 12 being the bottom plate and the second plate 14B being the top plate.

The second plate 14 slides between the open position and the closed position passing through the intermediate position. The second plate 14 is responsible for loading the upper face 10B of the composite panel 4 as the second plate 14 moves towards the first plate 12.

FIG. 1 shows an open position where the second plate 14 is spaced from the first plate 12.

FIG. 2 shows an intermediate position where the second plate 14 partially descends towards the first plate 12.

FIG. 3 shows a closed position where the second plate 14 is completely lowered towards the first plate 12.

Form 2 also includes an intermediate plate 18 interposed between the first plate 12 and the second plate 14.

The intermediate plate 18 is connected to the first plate 12 by columns 20 able to slide in the openings 22 of the first plate 12. The intermediate plate 18 therefore moves with respect to the first plate 12 in accordance with the axis of movement Z-Z.

In an intermediate position as shown in FIG. 2, an intermediate plate 18 is positioned against the bottom face 10A of the composite panel 4, and a second plate 14 is positioned against the top face 10B.

In this example, in a closed position as shown in FIG. 3, the intermediate plate 18 is in contact with the first plate 12 and the columns 20 engage fully with the openings 22.

Form 2 is provided with at least one spring 24, the one or each spring 24 being disposed between the first plate 12 and the intermediate plate 18. One or each spring is oriented in the direction of travel Z-Z.

An intermediate plate 18 rests on one or each spring 24.

Preferably, one or each spring 24 partially engages a corresponding opening 26 in the first plate 12 to maintain spring 24 in a linear position along the direction of travel Z-Z.

One or each spring 24 counteracts the movement of the intermediate plate 18 towards the first plate 12 in their direction of travel Z-Z. One or each spring 24, while moving the upper plate from the intermediate position to the closed position, is adapted to apply to the composite panel 4 a pressure less than a threshold compression pressure on the core 4, in particular less than or equal to 400 kPa.

Form 2 also includes at least one closure guide 30 affixed to the first plate 12 and extending towards the second plate 14. Preferably, the mold 2 includes a plurality of guides 30 distributed over its circumference to cut through the composite panel 4. Alternatively, the guide 30 may be curved, in order to form the rounded side edges 8 of the composite panel 4.

In FIG. 1 to 3, there are shown two locking guides 30 extending on opposite sides of the intermediate plate 18. Each guide 30 includes a base 32, a sharp edge 34, and a tilted face surface to fold the lower cladding 10A.

The guide 30 separates the inner space of the mold 2 from the outer space.

The base 32 of the track 30 defines a bead which, in the closed position, is flush with the upper surface of the intermediate plate 18, as shown in FIG. 3.

PL 230 650 B1

The sharp edge 34 is oriented opposite the second plate 14. The sharp edge 34 is adequate for contact with the second plate 14 in a closed position, as shown in FIG. 3. Thus, by pinching, it is able to cut a lower cladding 10A and an upper cladding 10B.

The sharp edge 34 is moreover able to cut the core 6 when the mold 2 is moved from the intermediate position, thereby forming a side face 8.

The sharp edge 34 has, for example, a metal blade.

An intermediate plate 18 in the open position is interposed between the guides 30 in their Z-Z travel direction, lying between the base bead 32 and the sharp edge 34,

The tilted face 36 of each guide 30 is oriented towards the intermediate plate 18. The tilted face 36 has a perpendicular angle with respect to the sliding direction Z-Z comprised between 80 [deg.] And 90 [deg.]. The tilted face 36 is configured to press the lower face 10A against the side face 8 in a closed position.

Thus, the tilted face 36 as the second panel 14 moves from the intermediate position towards the closed position is able to wrap the bottom facing 10A around one of the side faces 8 of the core 6.

The guide 30 has a height between the base bead 32 and the sharp edge 34, equal to the height of the core 6 and the lower and upper facings 10A, 10B. This allows the tilted face 36 to wrap the bottom facing 10A over the entire height of the side face 8.

Thus, the sharp edge 34 contacts the bottom cladding 10A in an intermediate position, as shown in FIG. 2.

Similarly, the sharp edge contacts the second plate 14 in a closed position as shown in FIG. 3 by cutting the core and lower and upper facings 10A, 10B.

Preferably, the mold 2 further comprises a support assembly suitable for holding the core 6 of the lower liner 10A and the upper liner 10B against the second plate 14 across from the guide 30. As a result, this facilitates the entry of the linings 10A, 10B into the inner space of the mold 2 from the outside. .

For example, the support assembly comprises side bolsters 40 mounted slidable relative to the first plate 12, parallel to the Z-Z axis, and flexible translation devices 42, e.g. springs, which counteract the side bolsters 40 to move towards the first plate 12.

The side bolsters 40 are positioned outwardly relative to the guide 30, and thus the guide 30 is inserted between the intermediate plate 18 and the side bolsters 40.

Preferably, the first plate 12 is adapted to receive at least one compensation insert positioned between the first plate 12 and the intermediate plate 18. For example, the first plate has incisions transversely from the intermediate plate 18 adapted to retain one or each compensation insert. This allows the form 2 to be adapted to composite panels 4 containing cores 6 of different thicknesses.

A method of manufacturing the composite panel 4 using a mold 2 will be described below.

The manufacturing method includes the step of pre-feeding the mold 2.

The previously described core 6 is fed into the mold.

If necessary, one or more compensating inserts are placed between the first plate 12 and the intermediate plate 18 to match the mold 2 with the thickness of the core 6.

A lower face 10A, as described above, is placed on the lower face 7A, and the upper face 10B is placed on the upper face 7B. Preferably, the lower face 7A and the upper face 7B of the core 6 are coated with an adhesive prior to placing the facings 10A, 10B.

Thereafter, a pre-heating step is performed during which the core 6 and the facings 10A, 10B are placed between the heating plates, and the facings 10A, 10B are brought to a temperature above the melting point of the polymer matrix, for example between 200 ° and 270 ° C.

Then, the core 6 and the linings 10A, 10B are placed in the inner space of the mold 2, between the second plate 14 and the intermediate plate 18. The linings 10A, 10B and the core 6 extend into the outer space of the mold 2, i.e., extend beyond the guides 30 as shown. in FIG. 1.

The second plate 14 then moves towards the first plate 12 along the axis of travel Z-Z.

The second plate 14 passes through the intermediate position shown in FIG. 2.

The intermediate plate 18 and the second plate 14 are then simultaneously respectively positioned in contact with the lower cladding 10A and the upper cladding 10B.

PL 230 650 B1

The springs 24 apply pressure as the second plate 14 moves, the intermediate plate 18 locks the facings 10A, 10B on the faces 7A, 7B of the core 6. The pressure exerted by the intermediate plate 18 on the composite panel 4 is less than the threshold crushing pressure on the core 6, which therefore does not deforms plastically.

However, as soon as the second plate 14 moves to the intermediate position, the facings 10A, 10B will be subjected to pressure. As the second plate 14 advances, the sharp edge 34 of each guide 30 cuts the core 6 to form the side face 8, while the sloped face 36 tucks the bottom cladding 10A around the side face 8. The intermediate plate 18 supports the bottom cladding 10A in position on the bottom. face 7A and pulls a portion of lower face 10A located in the outer space of the mold 2 onto the side face 8.

In addition, side bolsters 40 retain core 8, lower cladding 10A, and top cladding 10B against second plate 14 across from each track 30, which facilitates lower cladding 10A to extend from outer space into inner mold 2 space.

This limits the build-up of tensile stresses in the lower facing 10A, in particular at the edge of the core 6, which could cause local crushing deformations of the side faces 8 of the core 6.

The area of the lower face 10A which curls on the side face 8 of the core 6 only enters from the outside and not from the center of the mold 2, the area of the lower face 10A in contact with the lower face of the core 6 remains fixed. Thus, the angle between each side face 8 and the lower core face 7A remains close to 90 °.

Then, the intermediate plate 18 will make contact with the first plate 12.

The second plate 14 exerts a pressure in excess of the threshold crushing pressure on the core 6, thereby deforming the core 6 plastically to a small thickness, for example less than 2 mm, and in particular comprised between 1.5 mm and 0.5 mm.

The sharp edges contact the second plate 14 and cut the core 6 as well as the lower and upper facings 10A, 10B.

The pressure on the second panel 14 is maintained long enough on the composite panel to fix the facings 10A, 10B on the core 6 on the lower face 7A, the upper face 7B, and each side face 8.

After reopening the mold 2, as soon as the temperature drops again, the intermediate plate is lifted upwards by the spring (s) 24, which facilitates the removal of the composite panel from the mold 2.

The form 2 and the manufacturing method described allows composite panels 4 to be manufactured in one step, with edges having angles close to 90 [deg.], With reduced manufacturing costs and cycle times.

Claims (9)

Patent claims 1. A mold (2) for producing a composite panel (4), wherein the composite panel (4) comprises a core (6) and at least one bottom facing (10A) applied to the lower face (7A) of the core (6) and to at least one a side face (8), form (2) comprising: - a first plate (12); - a second plate (14), slidable with respect to the first plate (12) in their direction of travel (Z-Z), between an open position and a closed position; and - at least one closing guide (30) stationary with respect to the first panel (12) and projecting towards the second panel (14) simultaneously defining an interior space for forming the panel (4), the guide (30) comprising a bevelled face (36) for folding the lower cladding (10A) over the side face (8) of the core (6); characterized in that the mold (2) further comprises an intermediate plate (18) mounted on the first plate (12) in the inner space, the intermediate plate (18) being slid with respect to the first plate (12) in their direction of travel (ZZ), where between the first The first plate (12) and the intermediate plate (18) are provided with at least one spring (24) arranged in the direction of travel of the plates, the one or each spring (24) resisting the sliding movement of the intermediate plate (18) in towards the first plate (12). 2. Form (2) according to claim 1 The device of claim 1, characterized in that the intermediate plate (18) is flush with the base (32) of the or each track (30) in a closed position. 3. Form (2) according to any one of the preceding claims. 1-2, characterized in that the tilted face (36) of the or each guide (30) has a perpendicular forming an angle with the axis of displacement (ZZ) comprised between 80 ° and 90 °, the tilted face (36) being oriented towards the intermediate plate (18). 4. Form (2) according to any one of the preceding claims. A guide as claimed in 1-3, characterized in that in the open position the guide (30) projects beyond the intermediate plate (18). 5. Form (2) according to any one of the preceding claims. 4. The track according to any of the claims 1-4, characterized in that the or each track (30) has a sharp edge (34) oriented towards the second plate (14), the sharp edge (34) being adapted to come into contact with the second plate (14) at a time. closed position and cutting the lower cladding (10A). 6. Form (2) according to any one of the claims A plate according to any of the claims 1-5, characterized in that it comprises at least one removable compensation insert positioned between the first plate (12) and the intermediate plate (18). Form (2) according to any one of the preceding claims. A device according to any of the claims 1-6, characterized in that it comprises means for applying shock-absorbing back pressure to the second plate (14) in the closed position. 8. A method for manufacturing a composite panel (4) using a mold (2) as defined in any of the claims 1-7, characterized in that it comprises the following steps: - form introduction (2); - feeding a core (6) and a lower face (10A) across from the lower face (7A) of the core (6); - sliding the second plate (14) towards the closed position; - interlocking the lower cladding (10A) with the lower face (7A) through an intermediate plate (18), the core (6) being positioned in the inner space of the mold (2); - cutting the core (6) with a guide (30) to form a side face (8) of the core (6); and - contacting the deflected curving face (36) of the guide (30) with the lower cladding (10A) to apply the lower cladding (10A) to the side face (8); - removing the composite panel (4) from the mold (2). 9. The method according to p. The method of claim 8, characterized in that the intermediate plate (18) exerts pressure on the composite panel (4) below a threshold crush pressure on the core (6) when the first plate is moved between the intermediate position and the closed position.