FR2698578A1 - Continuous mfr. of composite parts, esp. trim - involves moulding trim ends into plastics coating on metal backing strip - Google Patents

Abstract

Continuous mfr. of composite parts (25), esp. useful as automobile trim, from a continuous composite bead profile (20) comprising a metal strip support (2) and a plastics coating (21,22), involves subjecting a continuously payed-out opt. profiled metal strip (2), to degreasing, heating, adhesive application, coating with plastics (21,22) by co-extrusion onto one or both strip faces and cooling. Between the plastics coating and cooling steps, the plastic is moulded at regular intervals for simultaneous formation of the ends of the composite parts (25) and, after cooling, the metal strip (2) is cut at the regions of these ends to form the composite parts (25). Also claimed are an appts. for carrying out the above process and a composite part made by the above process. ADVANTAGE - Any desired end shape can be produced without expensive subsequent operations and the plastics coating has a homogeneous appearance even after ageing, esp. for parts having a reflective or metallised appearance.

Description

 The subject of the present invention is a process and an installation for the continuous production of composite parts which can be used in particular as a hubcap in applications such as construction, furniture, household appliances and more especially the automobile.

 The present invention also relates to a composite part obtained by this method.

 Composite parts of this type generally comprise a support or an insert formed by a metal strip and on at least one of the faces of which is deposited at least one plastic covering material.

 The metal strip is made up of a flat strip or a steel, stainless steel or aluminum profile.

A known method of manufacturing this type of composite part consists
- continuously pulling the metal strip,
- to degrease the metal strip,
- to glue the metal strip,
- to be deposited by coextrusion on at least one of the faces of the metal strip, at least one layer of plastic material to form a continuous composite strip,
- to cool the composite rod,
- then to cut, at regular intervals, this composite strip to obtain a succession of pieces of the desired length.

 Then, the ends of the composite parts thus formed are shaped according to the finish and the final appearance to be obtained.

 So far three methods of finishing the ends are used.

 The first method consists in carrying out a finishing operation by cutting and / or by milling. However, this operation has the drawback of being able to obtain only simple geometries.

 In addition, this finishing operation can only be carried out for solid sections.

 Another method consists in carrying out an overmolding finishing operation which makes it possible to produce all the desired external shapes.

 However, overmolding is an expensive operation and the overmolded part often presents, during aging, a different aspect from that of the extruded part.

 Finally, a method is known which consists in attaching preformed end pieces to the cut ends of the parts. However, this method makes it necessary to provide on these cut ends attachment zones for the end pieces.

 In addition, the attached end caps generally have a different appearance from that of the extruded part.

 This difference in appearance becomes more and more marked during the aging of the product.

 The object of the invention is to propose a method and an installation for the continuous production of composite parts which makes it possible to overcome the drawbacks mentioned above.

The subject of the invention is a process for the continuous production of composite parts which can be used in particular as a trim for motor vehicles, from a continuous composite rod of the type comprising a support formed by a metal strip and at least one plastic covering material, process in which
- the metal strip, possibly profiled, is continuously pulled,
- degreasing of the metal strip is carried out,
- the metal strip is heated,
- we glue the metal strip,
- said plastic covering material is deposited by coextrusion on at least one of the faces of the metal strip to form the composite strip,
- Cooling said composite strip, characterized in that, between the deposition of the plastic and cooling, the plastic is molded at regular intervals to simultaneously form at least two ends of composite parts and, after cooling, cut the metal strip at said ends to form said composite parts.

The invention also relates to an installation for the continuous production of composite parts for the implementation of the method mentioned above, from a continuous composite rod of the type comprising a support formed by a metal strip and at least one plastic covering material, said installation comprising
- means for continuously pulling the possibly strip metal strip,
- means for degreasing the metal strip,
- an oven for heating the metal strip,
- means for gluing the metal strip,
at least one coextrusion and deposition channel for said plastic material on at least one of the faces of the metal strip to form the composite strip,
- means for cooling said composite rod, characterized in that it comprises, between the coextrusion die and the cooling means, molding means at regular intervals from the plastic to simultaneously form at least two ends of parts composites and, downstream of the cooling means relative to the direction of movement of the metal strip, means for cutting said metal strip at said ends to form said composite parts.

According to other features of the invention
- The molding means comprise at least one mold comprising two opposite elements, independent and each arranged opposite one of the main faces of the composite strip, said elements being movable simultaneously, perpendicular to said main faces, and in that at at least one of the elements is provided on its face opposite with said plastic material, with two imprints of simultaneous forming of the rear end of a composite part and of the front end of the following composite part,
the mold can be moved in parallel and in synchronization with said composite rod,
the element of the mold provided with the imprints comprises heating means,
the element of the mold provided with the imprints comprises cooling means,
the cutting means comprise at least one cutting tool comprising two opposite, independent parts, each disposed opposite one of the main faces of the metal strip, said parts being movable simultaneously, perpendicular to said main faces, and in this that at least one of the parts is provided, on its face facing said plastic, with at least two blades of shape corresponding to the shape of the ends of the composite parts for simultaneously cutting the metal strip at the rear end of a composite part and the front end of the next composite part,
- The cutting tool can be moved in parallel and in synchronization with said composite strip.

 The subject of the invention is also a composite part, of the type comprising a metal strip and at least one plastic covering material, obtained by the process mentioned above.

The invention will be better understood with the aid of the description which follows, given solely by way of example and made with reference to the appended drawings, in which
- Fig. 1 is a schematic view in longitudinal section of an installation for implementing the method according to the invention,
- Fig. 2 is a sectional view on a larger scale of the mold for forming the ends of the composite parts,
- Fig. 3 is a perspective view of an element of the mold showing the forming impressions of the ends of the composite parts,
- Fig. 4 is a sectional view on a larger scale of the tool for cutting the ends of the composite parts,
- Fig. 5 is a perspective view of part of the cutting tool showing the blades for cutting the ends of the composite parts,
- Fig. 6 is a perspective view of an example of a composite part obtained by the method according to the invention.

 The installation shown diagrammatically in FIG. 1 comprises a coil 1 of a metal strip 2.

 This metal strip 2 consists of a flat strip of steel or stainless steel or even aluminum.

 The coil 1 is unrolled continuously and the metal strip 2 first of all optionally passes through a profiling device not shown, a degreasing device 3 in which this strip is degreased by a solvent or by ultrasound, a heating oven 4 in which the strip 2 is heated to a temperature between 160 and 220 C, defined as a function of the thermal inertia of the strip, then a sizing device 4a.

 Then, the metal strip 2 passes through a single-material or multi-material coextrusion die 5.

 This coextrusion die 5 at the head of the square makes it possible to deposit successively, on at least one face of the metal strip 2, on the one hand, either a first plastic material 21 or either a film of an adhesion product and, d 'other hand, at least one plastic material 22 for obtaining a composite rod 20 continues.

 Conventionally, the coextrusion die 5 comprises an inlet port 6 of the metal strip 2 and an outlet port 7 of the composite strip 20.

 The coextrusion die 5 also includes one or more channels 8 for admitting the first molten plastic material 21 or the molten adhesion product, connected to an extrusion machine 9.

 On the other hand, the coextrusion die 5 comprises one or more channels 10 for admitting the molten plastic material 22, connected to an extrusion machine 11.

 The installation comprises, downstream of the coextrusion die 5 relative to the direction of movement of the composite strip 20, means 30 for molding plastic material 21 and 22 at regular intervals to simultaneously form at least two ends of parts composites 25.

 According to an exemplary embodiment shown in FIG. 2, the molding means 30 comprise at least one mold 31 comprising two opposite elements 32 and 33, independent and each arranged opposite one of the main faces of the composite strip 20.

 These elements 32 and 33 can be moved simultaneously, perpendicular to the main faces of the composite strip 20.

 The elements 32 and 33 of the mold 31 can be moved in parallel and in synchronization with the composite rod 20.

 To this end, these elements 32 and 33 are either mounted on a back and forth movement system, or on a continuous system of the belt or chain type 34, as shown in FIGS. 1 and 2.

 In the case where the system for moving the elements 32 and 33 of the mold 31 is formed by a belt or a chain 34, several elements 32 and 33 can be mounted on each chain 34.

 As shown in Fig. 3, the element 32 is provided, on its face 32a facing the plastic 21 and 22, with two opposing impressions 32b for simultaneous forming of the rear end of a composite part 25 and of the front end of the next composite part 25.

 These impressions 32b have a shape corresponding to the shape of the ends of the composite parts 25 to be obtained.

 At regular intervals corresponding to the length of the composite parts 25 to be obtained, the elements 32 and 33 of the mold 31 move vertically so that the element 32 comes to be applied on the upper face of the metal strip 2 and that the element 33 is applied to the underside of said metal strip.

 The impressions 32b penetrate into the material 21 and 22 which is in the plastic state so as to simultaneously form a rear end of a composite part 25 and a front end of a next composite part 25.

 The element 33 serves as a support for the metal strip 2 during the forming by the element 32 of the ends of the composite parts 25.

 In the case where a plastic material 21 and 22 is deposited on the two main faces of the metal strip 2, the two elements 32 and 33 of the mold 31 have imprints of shape corresponding to the ends of the composite parts to be obtained.

 The element or elements 32 or 33 of the mold 31 comprising the imprints 32b are either heated by electrical resistances or by circulation of a heat-transfer fluid, or cooled by circulation of a heat-transfer fluid, depending on the appearance to be obtained from the plastic cover.

 Then, the composite parts 25, the ends of which have been previously formed by the mold 31 and which are always connected together by the metal strip 2 pass through a cooling device 13.

 Over the entire installation, the metal bacon sheet 2 and the plastic 21 and 22 are pulled continuously by conventional means, such as tracks 14, or any other traction system.

 Downstream of the traction means 14 with respect to the direction of movement of the metal strip 2, the installation comprises means 40 for cutting said metal strip 2 at the previously formed ends of the composite parts 25.

 These cutting means 40 comprise at least one cutting tool 41 comprising two opposite parts 42 and 43, independent and each arranged opposite one of the main faces of the metal strip 2.

 The parts 42 and 43 of the cutting tool 41 can be moved, on the one hand, simultaneously, perpendicular to said main faces and, on the other hand, in parallel and in synchronization with the composite parts 25.

 To this end, the two parts 42 and 43 of the cutting tool 41 are either mounted on a back and forth movement system, or on a continuous system of the belt or chain type 44, as shown in this embodiment.

 In the case where the system for moving the parts 42 and 43 is formed by a belt or a continuous chain, several cutting tools 41 can be mounted on each chain 44.

 At least part of the cutting tool 41, such as for example the part 42, is provided, on its face 42a (FIG. 5) with two blades 42b of shape corresponding to the shape of the ends of the composite parts 25 for simultaneously cutting the metal strip 2 at the rear end of a composite part 25 and the front end of the next composite part.

 The cutting of the composite parts 25 is carried out in the following manner.

 The parts 42 and 43 of the mold move vertically between each consecutive end of the composite parts 25 so that the blades 42b cut the metal strip 2 and that the part 43 of the cutting tool 41 comes to be applied on the underside of said metal strip 2 during cutting thereof.

 In Fig.6, there is shown an example of a composite part obtained by the method according to the invention.

 Thus, it is possible to continuously produce hubcaps, for example for motor vehicles, comprising, on the one hand, a metal strip giving the part a dimensional stability compatible with its use and at least one plastic covering material bonded to the metal strip giving to the room the desired aesthetic.

 The method and the installation according to the invention make it possible to produce all the forms of ends desired without any costly recovery operation and to give the plastic covering material a homogeneous appearance even after aging, in particular for appearance parts. shiny or metallic.

Claims (9)

 1. Process for the continuous production of composite parts (25) which can be used in particular as a hub cap for motor vehicles, from a continuous composite strip (20) of the type comprising a support formed by a metal strip (2) and at least one material cover plastic (21, 22), method in which  - the metal strip (2) possibly profiled is continuously pulled,  - degreasing of the metal strip (2),  - the metal strip (2) is heated,  - we glue the metal strip (2),  - said plastic material (21, 22) covering is deposited by coextrusion on at least one of the faces of the metal strip (2) to form the composite strip (20),  - said composite rod (20) is cooled, characterized in that, between the deposition of the plastic (21, 22) and the cooling, the plastic (21, 22) is molded at regular intervals to simultaneously form at least two ends of composite parts (25) and, after cooling, the metal strip (2) is cut at said ends to form said composite parts (25).  2. Installation for the continuous production of composite parts (25) for implementing the method according to claim 1, from a continuous composite rod (20) of the type comprising a support formed by a metal strip (2) and at least one plastic (21, 22) covering, said installation comprising  - means (14) for continuously pulling the metal strip (2) possibly profiled,  - means (3) for degreasing the metal strip (2),  - an oven (4) for heating the metal strip (2),  - means (4a) for gluing the metal strip (2),  - at least one die (5) for coextruding and depositing said plastic material (21, 22) on at least one of the faces of the metal strip (2) to form the composite strip (20),  - means (13) for cooling said composite strip (20), characterized in that it comprises, between the coextrusion die (5) and the cooling means (13), means (30) for molding at regular intervals of the plastic (21, 22) to simultaneously form at least two ends of composite parts (25) and, downstream of the means (13) for cooling relative to the direction of movement of the metal strip (2) of the means ( 40) for cutting the metal strip (2) at said ends to form said composite parts (25).  3. Installation according to claim 2, characterized in that the molding means (30) comprise at least one mold (31) comprising two opposite elements (32, 33), independent and each arranged opposite one of the main faces of the composite strip (20), said elements (32, 33) being movable simultaneously, perpendicular to said main faces, and in that at least one of the elements (32, 33) is provided, on its face (32a) facing with said plastic material (21, 22) of two cavities (32b) for simultaneous forming of the rear end of a composite part (25) and of the front end of the following composite part (25).  4. Installation according to claim 3, characterized in that the mold (31) is movable in parallel and in synchronization with said composite rod (20).  5. Installation according to claims 3 and 4, characterized in that the element (32) of the mold (31) provided with the impressions (32b) comprises heating means.  6. Installation according to claims 3 and 4, characterized in that the mold element (31) provided with the imprints (32b) comprises cooling means.  7. Installation according to claim 2, characterized in that the cutting means (40) comprise at least one cutting tool (41) comprising two independent opposite parts (42, 43) and each disposed opposite one of the faces main of the metal strip (2), said parts being movable simultaneously, perpendicular to said main faces, and in that at least one of the parts (42, 43) is provided, on its face (42a) facing the plastic ( 21, 22), of at least two blades (42b) of shape corresponding to the shape of the ends of the composite parts (25) to simultaneously cut the metal strip (2) at the rear end of a composite part ( 25) and from the front end of the next composite part (25).  8. Installation according to claim 7, characterized in that the cutting tool (41) is movable in parallel and in synchronization with said composite strip (20).  9. Composite part of the type comprising a metal strip (2) and at least one plastic covering material (21, 22), characterized in that it is obtained by the method according to claim 1.