A method and a device for the production of a molded part having a plurality of different decorative regions that abut on each other

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DESCRIPTION

Method and device for the production of a molded part with several different decorative areas, adjacent to each other.

The present invention relates to a process for the production of a molded part with different decorative areas, adjacent to each other by overmolding several different decorative sheets placed in a molding tool comprising a molding tool core and a tool die of molding.

The present invention also relates to a molding tool for the production of a molded part with several different decorative areas, adjacent to each other.

It is known to refine certain areas of molded parts for interior trim of vehicles with fabric materials, plastic sheets, felt or upholstery materials, leather or also imitations of leather as decoration. In this regard, the decorative areas, in addition to the special optical and haptic properties, may also have special technical functions. Typically for the production of molded parts with integrated decorative areas, corresponding decorative fabrics or sheets are placed in a molding tool and then overmoulded with thermoplastic plastic, the edge area of ​​the decorative element being treated in most cases in one work operation. separated before the final finishing of the molded part.

In order to provide a molded part with different surface structures or decorative areas, two or more separate parts with different surface structures are often prefabricated on different tools as a semi-finished product and then joined together. However, this procedure has the disadvantage that several processing steps and transport operations have to be carried out and coordinated with each other, which is associated with a considerable investment of time and effort in manufacturing technology.

In EP 1 655 122 A1 a process for the production of plastic molded parts is described, in which in a first manufacturing step a first fabric or a decorative foil is placed on a molding tool and a rear injection is applied and then a part is stamped from the semi-finished product thus produced. In a second stage, a second fabric or a second decorative sheet is then placed in place of the piece removed from the semi-finished product and then the semi-finished product is also overmoulded in the area of ​​the second fabric or of the second sheet. Also in this case, several working steps are required to obtain a molded part with different decorative areas.

In almost all processes for the production of molded parts for vehicle interior linings with different known and implemented decorative areas, it is usual that either during the production of the molded part or at the latest after its finishing, the edge of the part is trimmed. decorative area, to achieve a perfect and optically correct adaptation of the decorative element to the molded part. In general, in the production of moldings of this type, a clean and optically flawless configuration of the edge region of a decorative element constitutes a major problem.

In the publication for patent application information DE 10 2005 029 849 A1 a process for the production of a composite element for the bodywork of a vehicle is described, at least two flat pieces of an external skin being placed next to each other in a common tool and providing the tool over its entire surface with a common support structure. The method provides for placing pieces of the outer skin as separate pieces in the tool, with adjacent pieces of the outer skin overlapping at the edge in a sealed manner. The disadvantage of this process is that the transition zone between the different individual surfaces causes an important optical delimitation between the surfaces, so that this process is only suitable for the production of bodywork elements in the external zone, in which they want such transitions or that, with corresponding measures, such as the laying of a slat, they can be lined. For the production of molded parts with different decorative areas for the internal trim of vehicles, in particular instrument panels, side trim or door trim, the method described in the document is not suitable.

Document DE 103 20 210 A1 describes internal lining parts with decorative elements, in which the edge area of ​​the decorative element is covered over its entire circumference by a decorative recess edge, creating a flat contact connection between the element. decorative edge, the edge area and the decorative recess edge. In this case, although the problem of the formation of an irregular joint along the edge area of ​​the decorative element has been solved without additionally cutting the decorative sheets, however a development of the joint or exact edge between the decorative element and the lining part can only be achieved by gluing or combining a plurality of different components together, which is correspondingly complex.

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Document EP 1 160 070 A2 describes a method and a device for the production of a molding with several different decorative areas, adjacent to each other, in which at least one decorative foil is placed in the cavity with the aid of a clamp. of an open molding tool, comprising a die and a core and is fixed with the help of pushers integrated into the core. The decorative foil is then overmoulded while retracting the pusher on the core side with a thermoplastic plastic. Since the at least one decorative foil is only deposited on the molding tool by the clamp, the jaw is then removed from the molding tool and only then is the loosely placed decorative foil fixed on the molding tool between the pusher. core and matrix core, there is a risk of displacement of the at least one decorative foil, which can adversely affect the optical appearance of the decorative area.

The aim of the present invention is to provide a method and a device for the production of molded parts with several different decorative areas, adjacent to each other for internal linings of vehicles, with the help of which the decorative areas can be inserted into the molded part in such a way, that there is a clean transition, precisely at the joints and optically correct between the individual decorative areas with a defined gap between their transition in the final product.

This object is solved by a method with the characteristics of claim 1 and a device with the characteristics of claim 7. Preferred embodiments of the method according to the invention and of the device according to the invention are indicated in the respective dependent claims.

With the help of a molding tool, which essentially consists of a molding tool core and a molding tool die, it is possible to produce plastic molded parts with different decorative areas, no further finishing or coating of the material being necessary. border area of ​​the decorative elements. This molding tool is combined with a jaw and the different decorative sheets are arranged on this jaw, which has a movable jaw frame as well as a jaw plate. In this case, the decorative foils are arranged with their edge in the area of ​​the jaw frame and overlap each other in their edge area. Now, with the aid of the clamp, the decorative foils are placed in the cavity of a molding tool, by pressing the overlapping decorative edges with the aid of the clamp frame into grooves, which are provided correspondingly to the clamp frame. in the core of molding tool. The decorative sheets are thus fixed on the surface of the molding tool core.

In order to keep the decorative sheets also when the jaw of the tool is removed from the surface of the molding tool, pushers integrated in the molding tool core are activated, arranged in the area of ​​the grooves, which in turn engage in the grooves and push the jaw frame out of the grooves, while fixing the decorative sheets. After the jaw has been removed from the tool area, the molding tool can be closed with the aid of a molding tool die, the molding tool die according to the invention having cores corresponding to the pushers integrated in the core of the molding tool, which now in the closed molding tool separates the different decorative areas with the different decorative foils from each other. In the overmolding on the core side of the decorative foils, these are pushed in each case against the die surface or with their edge region against the abovementioned webs.

After opening the molding tool, a molded part is thus provided with two different adjacent decorative areas, which are separated from each other by a narrow groove, arranged in the holder of the molded part, into which the edges of the molded part are inserted. the decorative sheets that cover the decorative area in each case. The webs arranged on the matrix are preferably dimensioned in such a way that the grooves obtained in the support are extremely narrow and the edges of the decorative areas are cleanly separated from each other, without affecting the optical impression. . In an advantageous configuration of the present invention the groove separating the two decorative zones is kept so narrow that the edges of the respective decorative zones almost directly limit each other.

As decorative films, fabrics, decorative materials, plastic films, tapestry materials, leather and / or imitations of leather can be used. Thermoplastic plastics are commonly used for overmolding decorative sheets, polypropylene (PP), polyethylene (PE), polyurethane (PU), acrylonitrile-butadiene-styrene (ABS), acrylonitrile-butadiene-styrene / polycarbonate copolymer being used as suitable plastics. (ABS-PC) or polyamide (PA).

An advantageous configuration of the present invention provides that several movable pushers are used as the jaw frame, which then as necessary grip the sheets individually and insert them into the corresponding grooves in the molding tool core.

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Another advantageous configuration of the present invention provides that the jaw has a jaw plate protruding from the jaw plane, mounted on springs, with the help of which the decorative sheets can be pushed onto the surface of the molding tool core and fixed thereon.

The present invention also relates to a device for the production of molded parts with several different decorative areas, adjacent to each other, the device comprising a molding tool with a molding tool core and a molding tool die as well as a jaw. with a jaw plate and a movable jaw frame for the placement of different decorative sheets that overlap each other in their edge area on the molding tool. In this regard, the jaw frame serves to insert the decorative edges into grooves provided for this in the mold tool core, which in turn are combined with pushers which are also integrated in the mold tool core, with the help of which subsequently the jaw frame can be pushed out on the core side of the grooves. In this case, the pushers in turn fix the decorative foils on the surface of the molding tool. The device also includes a molding tool die, which has cores corresponding to the pushers integrated in the molding tool core, which separate the different decorative areas from each other during the molding of the molded part.

Advantageous configurations of the device according to the invention provide that a number of movable pushers are provided as a jaw frame independently of one another and / or that a jaw plate protruding from the jaw plane, mounted on springs, is provided as a jaw plate.

In the following, the present invention is explained by means of drawings in detail. In this regard, Figures 1 to 5 show in cross-section, in each case a fragment of a molding tool core as well as a corresponding jaw before, during and after the placement of the different decorative sheets on the molding tool, Figure 6 in a cross section, a fragment of the closed molding tool before overmolding the decorative sheets, Figures 7 to 9 in a cross section, By fragment individual stages of overmolding, Figure 10 in a cross section, a fragment of the finished molding, Figures 11a to 11c in a cross section, different configurations of the molding tool core, Figures 12a to 12d in a section cross-section, different configurations of the jaw and Figures 13 to 19 also in a cross-section, by fragments of the jaw, molding tool and die in the development of the procedure when using a jaw with a movable double jaw frame.

In Figures 1 to 5, in a cross-sectional representation of fragments of the core 2 of the molding tool and of the jaw 4 the general development of the method according to the invention until the final placement of the different decorative sheets. Thus, in FIG. 1 a fragment of the jaw 4 is represented, on which different decorative sheets 9 and 10 are arranged, the edges of which overlap each other in the area of ​​the jaw frame 6. In this representation it is a snapshot shortly before the placement of the decorative sheets 9, 10 in the molding tool, of which the core 2 of the molding tool is represented by fragments with the grooves 7 arranged therein, which are arranged correspondingly to the jaw frame 6. In the molding tool core 2 in the region of the grooves 7, pushers 8 are integrated in each case, which correspond to the jaw frame 6 or the grooves 7.

FIG. 2 shows in the same way of representation the next process step, in which the decorative sheets 9 and 10 are applied superficially to the core 2 of the molding tool with the aid of the clamp 4. The jaw frame 6 is still in the initial position and the edges of the decorative sheets 9 and 10 are overlapping above the grooves 7 on the molding tool core 2.

Figure 3 illustrates the next process step, in which the edges of the decorative sheets 9 and 10 are inserted with the aid of the jaw frame 6 into the grooves 7 arranged in the core 2 of the molding tool. At the same time, in this connection, the decorative foil 9 is fixed with the aid of the clamp plate 5 on the surface of the molding tool core 2. By slidingly inserting the edges of the decorative foil into the groove 7, the overlapping of the decorative foils 9, 10 is eliminated and the edges of the decorative foils 9, 10 each cover the side walls of the groove 7.

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The next stage is observed in Figure 4, the decorative sheets 9, 10 being fixed with the help of the clamp on the surface of the core 2 of the molding tool and sliding the clamp frame 6 out with the aid of the pushers 8 integrated in the core 2 of the slot molding tool, while at the same time the blades 9, 10 are fixed with the help of the pusher 8 in the slot.

In Fig. 5 the positioning operation has finished and the clamp 4 moves together with the clamp plate 5 and the clamp frame 6 out of the molding tool, while on the surface of the molding tool core 2 they are the different decorative sheets 9 and 10 fixed by means of the pusher 8 and arranged separately from each other.

Figure 6 shows the closed molding tool 1, in which the molding tool matrix 3 now closes the molding tool 1, the webs 11 corresponding to the pushers 8 with the webs 8 forming a joint closure and subdividing this mode the molding tool into individual cavities.

The individual stages of the overmolding can be seen in FIGS. 7 to 9. For this, in FIG. 7, firstly, the injection channel 16 is also shown on the molding tool core 2, which always exists in the molding tool core. However, its representation in most of the figures is dispensed with in order to simplify the representation. Figure 7 shows the moment of the process of overmolding the external decorative sheets 10 with the thermoplastic plastic 15. While the decorative sheet 10 is still held with its edge in the groove 7, the corresponding cavity of the tool has already been partially filled with thermoplastic plastic 15, the decorative sheet 10 with the decorative surface being pushed against the die 3. The cavities for the different individual decorative areas are separated from each other by the still existing connection between pusher 8 and web 11.

In Figure 8 the decorative sheet 10 is completely overmoulded and now also abuts with its edge on the web 11, while the cavities for the individual decorative areas are still separated from each other and the overmolding of the decorative sheet 9 has not yet started. intermediate.

Figure 9 shows the closed molding tool with the molded part completely overmolded. To this end, the pushers 8 have returned to their initial position and the cavities for the individual decorative areas are connected to each other and completely filled with thermoplastic plastic.

A cross section of the finished product (molded part) is represented as a fragment in FIG. 10, the support 14 being covered with two different decorative sheets 9, 10, which in each case are inserted with their edges in a groove 7. In this representation it should be taken into account that this is a drawing that will explain the principle of the process and that the groove 7 that actually appears later in the molded part is preferably very narrow, so that the individual decorative areas limit each other in such a way direct and thus an optically correct impression is ensured, the edges of the decorative areas being cleanly separated from each other.

Different configurations of the core 2 of the molding tool are also illustrated in cross-section in Figures 11a to 11c. Thus, in FIG. 11b a slot 7 with an oblique edge can be recognized, with the help of which the insertion of the decorative sheets into the slot 7 is facilitated. In FIG. 11c a configuration of the molding tool core 2 can be seen, which is designed for the production of molded parts, the different decorative areas of which are additionally arranged on different planes of the molded part.

Figures 12a to 12d also show in cross-section some fragments of different configurations of the jaw 4.

In this respect, FIG. 12a shows the simplest embodiment variant, in which the jaw 4 with the jaw plate 5 has a plane and the jaw frame 6 is made in one piece.

Figure 12b shows a variant, in which the jaw plate 5 is elastically mounted on the jaw 4 and together with the jaw frame 6 protrudes from the jaw plane. The advantage of this variant is that in the placement of the decorative sheets 9, 10 the decorative sheet 9 is firmly pressed onto the core surface of the molding tool due to the elastic force and thus a displacement of the sheet is prevented. foil on placement in the molded part. The image does not represent the spring itself.

In FIG. 12c, a flat jaw 4 can be seen, which has a two-piece jaw frame, the jaw frame being composed of an internal pusher 13 and an external pusher 12.

In figure 12d an additional configuration of the jaw 4 is shown, in which the jaw plate 5 protrudes elastically from the plane of the jaw and for the introduction of the different decorative sheets 9, 10 into the corresponding grooves in the core of molding tool a frame 6 of

ES 2 397 503 T3 jaw, which is already only arranged with a form-drag with respect to jaw plate 5, while with respect to jaw 4 it has a gap, which allows a special type of overlap of the different blades 9 and 10 decorative. Depending on the nature of the individual decorative foils, this jaw variant can provide advantages. In this case, the spring itself is not shown either.

Figures 13 to 19 represent in each case in a cross-section in a manner analogous to the process shown in Figures 1 to 6, a process run with a jaw frame made of two pieces, the jaw frame having a pusher 13 internal and an external pusher 12, which are used successively from the inside out to introduce the respective decorative sheets 9, 10 into the grooves 7. Since the other process steps correspond to the procedure already explained by means of Figures 1 to 6, a detailed description of Figures 13 to 19 is omitted.

The above embodiments as well as the corresponding images, in which an attempt is made above all to explain the principle of the process, are essentially concentrated on two different decorative areas. It is understood by itself that the principle can be applied for any number of different decorative zones. The term decorative area is to be understood in this regard not only to areas covered with a decorative foil, but also to any visible areas of the molding, the decorative surface of which is also formed directly on the support of the molding, so that the principle of the invention can already be put into practice by using a single decorative foil, when, for example, with reference to the figures described above, only the intermediate decorative sheet 9 with the clamp 4 is placed on the tool and the cavities are then overmoulded in a manner analogous to figures 7 to 9, the external cavities then being filled directly with the plastic 15 thermoplastic and the decorative surface being formed in these areas as a negative of the matrix surface. The term "decorative foil" is to be understood according to the invention also for the most part already preformed decorative elements, which are placed on the tool by means of the clamp 4.

List of reference numbers molding tool molding tool core molding tool die jaw jaw plate jaw frame (pusher) groove pusher decorative foil decorative foil core external pusher internal pusher thermoplastic plastic holder injection channel