FR3017322A1 - INJECTION INSERT COATING ON THE BACK OF A SKIN - Google Patents

Abstract

The subject of the present invention is a method for producing a plastic part with an insert (2) having a front face (3), visible, and an opposite rear face, said method comprising the steps essentially consisting in opening a mold, providing said insert (2), positioning a skin (6) of material in the mold, at least at the position of the insert (2) in the mold, against its rear face (4), in particular a skin (6) flexible closing the mold, then injecting plastic material into the mold, against the skin (6), on the opposite side to the insert (2), and finally ejecting the plastic part of the mold with said insert (2). This method is characterized in that during the injection, the skin (6) is pressed into the mold by the injected material, so that it matches the shape of the latter as well as the insert (2), which last being then maintained in said skin (6). The invention also relates to a tool and a corresponding part.

Description

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to the field of plastic parts for the interior lining for a vehicle, in particular for a motor vehicle, and relates to a method of particular embodiment of such a part, a tool dedicated to the implementation of this invention. process and a plastic part thus obtained. A piece of trim, in particular a dashboard, must have a pleasant touch and therefore generally has a soft skin on its surface. Under this skin, the lining piece generally has a support or more rigid substrate, often obtained by plastic injection. The lining piece can also be obtained by thermocompression of the different components manufactured separately, or even subsequently undergo a thermoforming step to give it its final shape.

There are processes where the skin is thermoformed on the rigid support. However, for the purpose of reducing manufacturing time and tooling costs, it is particularly advantageous to be able to produce this type of plastic part in a single step, by thermocompression or by injection.

For this purpose, in the methods of the field of the present invention, an elastomeric thermoplastic sheet is fed into the mold, the injected material then being pressed against the surface of the cavity in the mold. The piece thus obtained thus takes the form of a support obtained by injection, covered with a thermoplastic sheet which matches the contours of the mold cavity. Various evolutions have been proposed in order to obtain several visual renderings for a piece obtained in this way, with one and the same tooling. Thus, for example, WO2008 / 011068 discloses a method in which an insert is placed against a wall of the mold before it is closed, and removed from the resulting part to leave a corresponding shaped cavity therein. The object of the present invention is to improve the existing state of the art by increasing the possibilities of customizing a piece of lining with the same tooling, and reducing as much as possible, or at least controlling, any disassembly, gap or other visible or detectable offset to the touch, which may appear between an insert left in the skin and the skin itself.

To achieve this object, the invention essentially proposes to embed the insert (or each insert in the case of a plurality of inserts) in the skin under the effect of injecting the material at the back, preferably by intimately wrapping. the rear face and the lateral sides of said insert, which then has the effect of encapsulating the insert in the skin sufficiently that it remains firmly maintained. For this purpose, the invention firstly relates to a plastic part production method with at least one insert having a front face, generally visible, and an opposite rear face, said method comprising the steps consisting essentially in opening a mold, providing said at least one insert, positioning a skin of material in the mold, at least at the position of the insert or each insert in the mold, against its or their rear face, in particular a flexible skin, closing the mold, then inject plastic into the mold, against the skin, on the opposite side to the insert or each insert, and finally eject or extract the plastic part of the mold with said at least one insert. This method is characterized in that during injection, the skin is pressed into the mold by the injected material, so that it matches the shape of the latter as well as that of the insert or each insert, this (FIG. s) last (s) then being maintained in said skin.

The invention also relates to a manufacturing tool implementing such a method and comprising a mold having a cavity defining the molding cavity, and means for opening and closing said mold, for injecting plastic into the cavity molding, as well as for ejecting the plastic part out of the mold.

This mold is characterized in that it further comprises means for bringing a skin into the mold cavity and retaining it therein at least during the injection of material into the mold, as well as means for bringing at least an insert in said mold. The invention also relates to the plastic part itself, 35 obtained by the implementation of such a method and by means of such a tool. This piece is characterized in that it comprises a skin, preferably an elastomeric material, which on one side has at least one insert and, on the opposite side, has a molded plastic base or substrate (e ). The invention will be better understood, thanks to the following description, which refers to preferred embodiments (presence of a single insert), given by way of non-limiting example, and explained with reference to the schematic drawings. attached, in which: - Figure 1 illustrates a first step of the method of manufacturing a plastic part with at least one insert according to the invention, where the tool is open; Figure 2 illustrates a particular insert structure; FIG. 3 illustrates a step of the method according to the invention, just before the injection of the material forming the substrate and presenting the position of the ejectors removed; FIG. 4 illustrates a step of the method according to the invention after injection of the material forming the substrate and representing the position of the ejectors retracted; - Figures 5 and 6 show each, in section, a plastic part according to the invention comprising an insert with opposite backs on the rear face; FIG. 7 shows, in relation to a plastic part seen in section and according to another embodiment of the invention, the possibility of using the insert to fix at least one other aspect element therein; FIG. 8 illustrates, in relation to a plastic part seen in section and according to another embodiment of the invention, another possibility of anchoring an insert; FIGS. 9A and 9B illustrate another alternative embodiment of an insert, seen from above and in section, and FIG. 10 shows, in sectional view, a plastic part obtained by the method according to the invention and incorporating An insert as shown in FIG. 9. The invention therefore firstly relates to a method of producing plastic part 1 with at least one insert 2 having a front face 3, visible, and a rear face 4, opposite, said method comprising the steps of essentially opening a mold 5, providing said at least one insert 2, positioning a skin 6 of material in the mold 5, at least at the position of the insert or each insert 2 in the mold 5, against its rear face 4, in particular a flexible skin 6, 4 - close the mold 5, then inject plastic into the mold 5, against the skin 6, the opposite side to the insert or each insert 2, and finally eject or extract the plastic piece 1 of the mold 5 with said at least one insert 2.

Although the description which follows relates preferentially to the presence and implementation of a single insert 2, the invention also relates to the use of two or more inserts 2 (see FIG. 7), each of which presents then at least the essential characteristics mentioned below, in relation to a single insert.

The insert or each insert 2 is intended to be fixed in the skin 6 permanently, that is to say to be fixed thereon once the piece 1 is out of the mold 5. Its front face 3 is normally visible once the piece 1 is positioned in a vehicle. The rear face 4 of the insert 2, opposite to the front face 3, is normally in direct contact with the skin 6. The front face 3 is normally flush with the outer surface of the skin 6. The skin 6, like it must come to coat or encapsulate the insert or each insert 2, is placed in the mold 5, so as to cover at least the rear face of the insert 2 concerned, preferably also the lateral sides to the visible face of the piece 1. The skin 6 is placed between the two parts of the open mold 5. When the mold 5 closes, the air gap between the two impression surfaces remains greater than the thickness of the skin 6, which is therefore not normally in contact with the entire cavity.

Preferably, the skin 6 is made of TPO, namely non-vulcanized olefinic thermoplastic elastomer, preferably of planar form, of a thickness of about 0.2 to 0.8, preferably about 0.5 millimeter. The insert or each insert 2 in turn takes the form of a flat element with a thickness of less than 1 millimeter, advantageously between 0.2 and 0.9 millimeters, preferably with a thickness of 0.4. and 0.6 millimeters. It may be made of a thermoplastic material, polycarbonate or a metallic material, such as aluminum. Once the skin 6 and the insert 2 are positioned in the mold 5, the arrangement is such that the insert is found between the skin 6 and a surface of the mold 5. In order to coat the insert 2 with the skin 6, under the effect of the pressure of the injected material, it is therefore necessary that the skin 6 is - 5 - between the injected material and the insert 2. Thus, preferably, the injected material arrives from the fixed part of the mold, the skin 6 is then between the fixed part and the movable part, the insert 2 being between the skin 6 and the movable part of the mold 5. The injected material is in particular polypropylene, foamed or not. According to the invention, during the injection, the skin 6 is pressed into the mold 5 by the injected material, so that it closely matches the shape of the latter (in fact the shape of the impression of the part of the mold against which the skin is plated) and that of the insert or each insert 2, the latter then being held in said skin 6 (by mechanical interlocking, optionally reinforced by gluing), which avoids a disintegrator and / or an excessive gap visible or felt to the touch. The insert or at least one of the inserts 2 is in the form of a thin part, in particular a thickness less than 1 millimeter, advantageously between 0.2 and 1 millimeter, preferably about 0.4 to 0.6 mm, then forming a portion of the outer surface of the final piece 1. Under the effect of the pressure of the injected material, the skin 6 comes to coat the insert 2. In addition, under the effect of heat and pressure, any offsets or désafleurs between the insert 2 and the skin 6 are avoided, since the skin 6 is even more flexible. In particular embodiments, providing the insert or each insert 2 consists in placing it in the open mold, independently of the skin 6, with its front face 3 against a surface of the mold 5, in particular against a continuous surface. For example, the insert 2 is placed in the mold 5 by means of a manipulator robot 13, and the skin is also placed in the mold 5 by a robot 13 'or similar means (shown schematically in the figure 1). The insert 2 can therefore be positioned and retained in the mold 5 even in the absence of the skin 6. During injection, the insert 2 is thus held directly against the mold 5.

A solution for securing the insert or each insert 2 on the mold 5 is therefore desirable, for example in the form of a layer of adhesive on the front face 3 of the insert 2. Thus, in general and according to an additional possible feature, the front face 3 is provided with a front fixing means 7 against the surface of the mold 5, in particular in the form of an adhesive layer, or a magnetic layer. In other embodiments, providing the insert or each insert 2 is done by positioning the skin 6 in the mold 5, the insert or each insert 2 being already present and maintained, for example by gluing, on the skin 6 when positioned in the open mold 5. The insert 2 is thus fixed on the skin 6 before it is brought into the mold 5. Thus, during the injection of the material at the rear of the skin 6, the insert 2 is retained on the 6 in the second case, an adhesive solution of the insert or each insert 2 on the skin can be used even before the closure of the mold 5, for example a layer of adhesive at the rear face 4 of the insert 2. Thus, generally and according to an additional possible feature, the rear face 4 of the insert or each insert 2 is provided with a rear fixing means 8 against the skin 6 and / or in folds of the skin 6, in particular in the form of a layer of adhesive or structures underdepoise. Said rear face 4 of the insert 2 or at least one insert 2 can thus, alternatively or additionally, be provided with anchoring means 14 passing through the skin 6 and intended to be enrolled by the injected material (harpoons 14, Figure 8). It may be advantageous to provide a fastening means both at the rear of the insert 2 considered at the front, to promote respectively a good attachment of the insert 2 in the skin 6 and a good hooking of the insert 2 in the mold 5 during the injection. In this case, the rear fastening means 8 against the skin 6 is more resistant (that is to say, has a greater resistance to breakage or separation) than the front fixing means 7 against the mold 5, so that the insert 2 remains in the plastic part 1 when it is ejected from the mold 5. The insert then functions as a decorative element in the final part 1. According to a possible additional feature of the method, it comprises an additional step consisting essentially of locally pressing the skin 6 against the insert or each insert 2 during the injection, for example by means of at least one ejector or pusher 9 movable, retractable in the mold part 5 located at a distance from said skin 6. This naturally ensures that the insert 2 remains in position during the injection, to ensure its position in the room 1 final. In some embodiments, pressing the skin 6 against the insert 2 is done by controlling ejectors whose mold 5 is provided, namely by removing them until their free end comes to press the skin 6 against the face back 4 of the insert 2 before the injection and entering them only - 7 - during the injection. At least one ejector 9 thus arrives opposite the insert 2 and, at least at the beginning of the injection, is sufficiently extended to press the skin 6 and the insert 2 against the surface of the mold 5. retraction ejector 9 can be achieved during the injection, so as to avoid a hole under the insert 2 after the piece 1 completed. The ejector may also simply be slightly returned at the beginning of the injection, then leaving a film of material injected between the skin 6, under the insert 2, and the ejector. The exit of the ejector can be provided as soon as the mold 5 closes, before or after the introduction of the insert 2 and the skin 6. The invention also relates to a manufacturing tool implementing the method described above. This tool, shown schematically in FIG. 1, and essentially in the form of an injection tool, comprises a mold 5 having a cavity defining the molding cavity, as well as means for opening and closing said mold 5 (for example by displacement of the movable part of the mold, Figure 1), for injecting plastic into the molding cavity, as well as for ejecting the plastic part 1 out of the mold 5. According to the invention, the tooling further comprises means 13 'for bringing a skin 6 into the mold cavity and retaining it at least during the injection of material into the mold 5, and means 13 for bringing at least one insert 2 into said mold 5. Such means may take the form of a movable frame in which the skin 6 is held with or without tension, or a set of clamps or other gripping means (robot arm), and which comes to place the skin 6 between the two parts of the mold 5 when open . When the insert or each insert 2 is mounted on the skin 6 before the latter is brought into the mold 5, bringing the skin into the mold 5 naturally returns to also bring the insert 2 into the mold 5. In these cases , the positioning means of the insert or the inserts 2, on the one hand, and the positioning means of the skin 6, on the other hand, are the same. When the insert 2 considered is held on the surface of the mold 5 and not on the surface of the skin 6, it can be brought into the mold 5 with the same manipulator robot, simultaneously or not with the removal of the insert 2 in In this case, the skin positioning means 6, on the one hand, and the positioning means of the insert 2, on the other hand, may be one and the same element, or take the form of two distinct elements. According to an additional possible feature, the tooling further comprises at least one ejector or pusher 9 movably mounted in an impression or part of the mold, which can be controlled so that its free end comes into the immediate environment of the mold. the impression or the opposite part, so as to press against the latter both the skin 6 and the insert 2 concerned. The ejector 9 and its actuating means, preferably a jack, and the associated control means, therefore allow to maintain an ejector in a partially extended position, with sufficient precision to effectively maintain the skin 6 and the insert 2 concerned against the mold 5, but without degrading either of these elements, nor by causing excessive buckling force on the ejector 9. The invention finally also relates to a plastic part 1, obtained by the implementing the method described above by means of the tooling described above. It is therefore a part obtained by injection, having a surface coating in the form of an elastomer thermoplastic layer, in which is embedded at least one decorative insert 2, itself possibly having a multilayer structure, of which by example an adhesive layer on the front panel, which can be removed before installation of the part 1, and a layer of back adhesive, to ensure its maintenance in the skin of thermoplastic elastomer. Thus, according to the invention, this plastic part comprises a skin 6, which, on one side, has at least one insert 2 and, on the opposite side, has a molded plastic base or substrate. The skin is preferably made of TPO, or thermoplastic elastomer, the base or the more rigid substrate being preferably in polypropylene, injected, the substrate material locking the encapsulation of the insert in the skin. Given the process used, and in particular by using a cavity surface of the continuous cavity where it is positioned, the insert or at least one of the inserts 2 comes flush with the outer surface of the skin 6 so as to form a surface without irregularity of appearance. Thus, thanks to the methods and tooling described, irregularities are avoided in the continuity of the outer surface, between the periphery of the insert 2 and that of the skin 6 surrounding it. Such irregularities may be visible to a user who sees the final piece opposite. Unwanted irregularities causing a gap between the insert 2 and the skin 6 around it, which can be detected by passing the hand on the outer surface of the final part 1, are also avoided. The insert 2 is thus completely embedded and surrounded by the skin 6.

Alternatively, it may also be provided to program a desired and controlled disintegrator between the insert or at least one of the inserts 2 and the surface of the skin 6 (recessed), in particular by adjusting the thickness of the adhesive layer on the front face 4 of the insert 2, which provides the connection between the latter and the wall of the mold.

Thus, the insert or at least one of the inserts 2 can be positioned flush with the outer surface of the skin 6 so as to form a surface without irregularity of appearance or, alternatively, with a recessed deblower by In particular embodiments, the insert or at least one of the inserts 2 has, at its rear face 4, specific means 12, 12 'such as cores or the like which promote the mechanical strength of the insert 2 in the plastic part 1. FIGS. 5 and 6 show examples of such alternative embodiments: either anchoring elements 12 formed or added to the rear face 4 of FIG. the insert 2, a particular shape given to the rear face 4 of the insert 2 through referrals 12 'which are not parallel to each other. Finally, in some embodiments, the insert or at least one of the inserts 2 has, at its front face 3, means 10 for fixing (removable or not) of at least one functional part and / or additional aspect, such as a surface with magnetic properties, an adhesive surface or the like, in order to be able to anchor on the insert 2 other functional elements and / or visible aspects (provided, if necessary, with complementary fixing means ) once the workpiece 1 in use, such as a decorative element 11. Figure 7 illustrates an embodiment having both anchoring means 12 with backsplits at the rear of the two inserts 2 present and a The facing piece 10 on the front face 3 of the inserts 2 represents an additional personalization element of the workpiece 1, while the tools used remain the same. - 10 - Finally, according to another characteristic of the invention illustrated by a particular embodiment of the insert 2 considered in Figures 9 and 10, but may also be provided for any of the variants shown in the other figures , it may be provided that the insert or at least one of the inserts 2 has at least one cutout or through opening 2 ', in which the skin 6 extends, the latter opening, preferably being flush, at the level of the front face 3, generally visible, of said insert 2. This portion 6 'of skin 6 is thus embedded in the cutout or the opening 2' (in the case illustrated in the form of a circular hole) following the injection of the 1 and material positively participates in the retention by encapsulation of the insert 2 considered in the plastic part 1. In addition, the visible portion and flush surface of the skin portion 6 'provides a visual and aesthetic appearance 3 Although FIG. 10 illustrates an insert 2 with a single through-orifice 2 ', a plurality of orifices of this type of larger or smaller diameters (preferably greater than about 1 mm) may be provided, being distributed more or less homogeneously on the surface of the insert. When the part 1 comprises several inserts 2, the person skilled in the art understands upon reading the present description, that the latter may or may not be constitutions, structures, shapes, colors, aspects and / or materials, and be positioned flush or partially or wholly out of alignment. Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications are possible, in particular from the point of view of the constitution of the various elements, by a different combination of all or part of the characteristics described above, or by substitution of technical equivalents, without departing from the protection field of the invention. 'invention.

Claims (15)

REVENDICATIONS1. A method of producing a plastic part (1) with at least one insert (2) having a generally visible front face (3) and an opposite rear face (4), said method comprising the steps of essentially opening a mold ( 5), providing said at least one insert (2), positioning a skin (6) of material in the mold (5), at least at the position of the insert (2) or each insert (2) in the mold (5), against its or their rear face (4), in particular a flexible skin (6), close the mold (5), then inject plastic material into the mold (5), against the skin (6) ), on the opposite side to the insert or each insert (2), and finally ejecting or extracting the plastic part (1) from the mold (5) with said at least one insert (2), characterized in that at injection, the skin (6) is pressed into the mold (5) by the injected material, so that it matches the shape of the latter as well as that of the insert or each insert (2), this ( s) rnier (s) being then maintained in said skin (6). 2. Method according to claim 1, characterized in that providing the insert or each insert (2) consists of placing it in the mold (5) open, independently of the skin (6), with its front face (3) against a surface of the mold (5). 20 3. Method according to claim 1, characterized in that providing the insert or inserts (2) is achieved by positioning the skin (6) in the mold (5), the insert or each insert (2) being already present and held, for example by gluing, on the skin (6) when positioned in the open mold (5). 25 4. Method according to any one of claims 1 to 3, characterized in that it comprises an additional step consisting essentially of locally pressing the skin (6), preferably an elastomeric material, against the insert or each insert (2) during the injection, for example by driving one or ejectors (9) whose mold (5) is provided. 5. Method according to any one of claims 1 to 4, characterized in that the front face (3) of the insert or each insert (2) is provided with a front fixing means (7) against the surface of the mold (5) and / or the back face (4) of the insert or each insert (2) is provided with a rear fixing means (8) against the skin (6) and / or in folds of the skin (6), such as, for example, a layer of adhesive or straddling structures 6. Method according to claim 5, characterized in that the rear fixing means (8) against the skin (6) is stronger than the front fixing means (7) against the mold (5). 7. Method according to any one of claims 1 to 6, characterized in that the insert or at least one of the inserts (2) is in the form of a flat element with a thickness of less than 1 millimeter , for example made of a thermoplastic material, polycarbonate or a metallic material, such as aluminum. 8. Manufacturing tool for carrying out a method according to any one of claims 1 to 7, comprising a mold (5) having a cavity defining the molding cavity, and means for opening and closing said mold cavity mold (5), for injecting plastic material into the molding cavity, as well as for ejecting the plastic part (1) out of the mold (5), characterized in that it further comprises means for bringing a skin (6) in the mold cavity and retain it at least during the injection of material into the mold (5), as well as means for bringing at least one insert (2) in said mold (5). 25 9. Tooling according to claim 8, characterized in that it further comprises at least one ejector or pusher (9) movably mounted in an impression or part of the mold, and which can be controlled so that its free end ( 9 ') comes into the immediate environment of the impression or the opposite part. 30 10. Plastic part (1) obtained by the implementation of a method according to any one of claims 1 to 7, characterized in that it comprises a skin (6), preferably an elastomeric material, which, d ' one side has at least one insert (2) and on the opposite side has a molded plastic base or substrate (1 '). 11. Plastic part (1) according to claim 10, characterized in that the insert or at least one of the inserts (2) is positioned flush with the outer surface of the skin (6) so as to form a surface without irregularity of appearance. 12. Plastic part (1) according to claim 10, characterized in that the insert or at least one of the inserts (2) is positioned with a deblower set back from the outer surface of the skin (6). . 13. Plastic part (1) according to any one of claims 10 to 12, characterized in that the insert or each insert (2) has, at its rear face (4), anchoring means (12, 12 '), in particular backed-off structures which promote the mechanical strength of the insert (2) considered in the plastic part (1). 14. Plastic part (1) according to any one of claims 10 to 13, characterized in that the insert or each insert (2) has, at its front face (3), means (10) for fixing an appearance part (11), such as a surface with magnetic properties, an adhesive surface or the like. 15. Plastic part (1) according to any one of claims 10 to 14, characterized in that the insert or at least one of the inserts (2) has at least one cutout or through opening (2 '), in which the skin (6) extends, the latter emerging, preferably flush, at the generally visible front face (3) of said insert (2).