Patent Application
20250178252
The present invention relates to a method and an injection molding die for producing a component composite.
In modern vehicle interiors, light apertures with decorative or informative functions are found. Light apertures consist of a carrier which has material voids at defined locations, with the result that the carrier is permeable for light at these locations. These locations have a defined shape, with the result that the light apertures are clearly contoured.
Customary carriers are manufactured using the injection molding method from a plastic such as polypropylene. Here, a transparent film is inserted into the die, behind or onto which film the plastic is injected. The die is shaped in such a way that defined locations which subsequently form the light apertures remain free.
It has been shown in practice that a loss of the dimensional accuracy can occur in the case of the material shrinkage of the carrier material on account of the bimetal effect which describes the deformation of a composite component with materials with different coefficients of thermal expansion. That is to say, the different behavior of the film and the carrier can lead to an undesired deformation of the finished component composite. Furthermore, the local deformation can be assisted by the fact that ribs are frequently configured on the carrier, which have a particularly large quantity of material in comparison with other component portions and, as a result, lead to a correspondingly inhomogeneous shrinkage behavior. As a result, visible sink marks arise on the surface of the finished component composite, in particular in the region of the film. The manufacture of a component composite of the generic type using a pure injection molding method is accordingly problematic.
An attempt has then been made to take account of this problem by way of the use of a foaming carrier material. However new difficulties have resulted from this. The expanding carrier material does not exactly follow the opening cavity of the injection molding die, and therefore cannot exactly reproduce the predefined contour. That is to say, the expanding carrier material cannot penetrate into acute angles of the injection molding die on account of its low foaming pressure, for example. Contours with angles of this type therefore cannot be reproduced exactly. In this case, the carrier material can assume a radius which only approximates the desired angle. Moreover, a deformation of the film can occur, furthermore, on account of an adhesive action of the foaming carrier material on the film in the region of the radii.
It is an object of the present invention to at least partially take account of the above-described problem. In particular, it is an object of the present invention to provide a component composite with a translucent film and a solid body which holds the film without undesired material deformations in a simple way.
The above object is achieved by way of the patent claims. Further advantages of the invention result from the dependent claims, the description and the figures. Here, it goes without saying that features which are described in conjunction with the method also apply in conjunction with the injection molding die according to the invention, and vice versa in each case, with the result that reference is and/or can be always made mutually with regard to the disclosure in respect of the individual aspects of the invention.
In accordance with a first aspect of the present invention, a method for producing a component composite for a vehicle is provided. The method comprises the following steps:
Using the mold body, the film is held in the desired position during the extended injection molding method. Moreover, the mold body is used as a placeholder for producing the desired material void in the carrier. In combination with the foaming carrier material and the injection body which moves relative to the mold body, stress-free production of the component composite can then be realized, even in the region of the material voids. It can be ensured, in particular, that the carrier material can penetrate as far as into the corners of the injection molding die, without an undesired deformation subsequently having to be feared in this region, for example a curvature and/or a sink mark of the film.
The foam pressure of the foaming carrier material ensures additional holding pressure during the entire cooling time for the component composite. As a result, the stresses which otherwise occur on account of thermal expansion and/or shrinkage can be considerably reduced. By way of the provided method, material voids for light apertures with relatively complex contours can be produced. As a result of the use of the foaming carrier material, a component composite can be produced which has a relatively low weight in comparison with a component composite made from conventional solid material. The final local density of the carrier material can be controlled by way of the shape and the movement of the mold body. That is to say, the mold body can ensure in relevant regions that the plastic remains locally compact, as a result of which the production of sink marks is prevented. For this purpose, the mold body can be shaped and/or moved in such a way that no room or only a small amount of room is left for foaming of the carrier material in the regions on and/or close to the transparent film. The mold body can be adjusted by way of an adjusting means in order to change the spacing between the mold body and the film inner side, in order to set the density of the carrier material during the foaming of the carrier material to the desired or a predefined value. In particular, the mold body can be adjusted hydraulically by means of a hydraulic system. Here, the mold body can be moved relative to the injection body.
As foaming carrier material, in particular, an integral foam can be used. The film can be understood to be a flexible and elastically deformable flat structure. The injection body preferably carries out a linear movement when it is moved from the injection position into the final molding position. The mold body can be understood to be a construction consisting of a plurality of mold body elements. The mold body elements can be configured such that they are spaced apart from one another and/or can be moved relative to one another, and can be moved accordingly in order to produce the component composite. The injection molding die can be understood to be a die for carrying out an injection molding method or a method which comprises an injection molding process. That is to say, the injection molding is not to be considered to be restricted to a pure injection molding method in the present case. The method is preferably carried out as an injection molding-integral foam method. In this way, even particularly complex cavities can be filled reliably with the carrier material.
In accordance with a further embodiment of the present invention, it is possible that, in the case of one method, the injection body is moved into a final molding position, in which the injection body is further away in a range between 50% and 150% from the film inner side than in the injection position. In other words, the injection body can first of all be moved onto the film inner side by a fraction of, for example, 50% of the planned final wall thickness of the carrier and, after the injection of the plastic in the form of the foaming carrier material, can be moved away into the final molding position. The distance of the injection body from the film inner side in the final molding position can therefore correspond to the final wall thickness or at least substantially to the final wall thickness of the carrier at the corresponding location of the carrier. By way of this procedure, the component composite can be produced particularly reliably with the desired shape, in particular without undesired ripples or bulges.
Furthermore, it is possible that, in the case of a method according to the present invention, the mold body loads the film with pressure during the injection molding in order to hold the film in a predefined position. In this way, the desired shape of the carrier and/or the component composite can also be produced in a simple way. A separate holding means and/or an additional holding means can be dispensed with.
In the case of a method according to the invention, moreover, it is possible that the foaming carrier material comprises an agent for releasing carbon dioxide and water. An agent of this type can be understood to be a blowing agent. A blowing agent of this type can comprise carbonate-containing and acid-containing compositions. The use of a corresponding carbonate/acid combination can lead to advantageous foam properties. Preferred agents can comprise, furthermore, citric or tartaric acid, in particular in combination with a metal carbonate. Moreover, chemical blowing agents for releasing N2, CO or CO2 can be used. The method is not restricted to chemical blowing agents, however. Physical blowing agents which are utilized, for example, in the case of thermoplastic manufacturing methods can in principle also be used.
Furthermore, it is possible that, in the case of a method according to the present invention, a laminating layer is applied on the film outer side. Possible unevenness on the film outer side can be laminated by means of the laminating layer. The laminating layer is applied in such a thin layer that a light source on the film inner side can still shine through the laminating layer and can be discerned by a person. That is to say, in particular, the laminating layer covers, preferably completely, the region of the film outer side, on the opposite film inner side of which the at least one material void is configured. The laminating layer is therefore preferably applied as a translucent laminating layer. An LED, for example, can be used as light source for shining through the laminating layer.
In accordance with a further aspect of the present invention, an injection molding die for carrying out a method as described above is provided. The injection molding die comprises an injection body and a mold body, it being possible for the injection body and the mold body to be moved relative to one another, and the mold body being configured to hold the film in a predefined position and to load it correspondingly with pressure to this end while the injection body moves from the injection position into the final position. In this way, the injection molding die according to the invention provides the same advantages as have been described in detail in relation to the method according to the invention.
In the case of an injection molding die according to the invention, it can be advantageous if at least one part of the mold body is of pin-shaped configuration. That is to say, the mold body can comprise one or more pin-shaped or plate-shaped mold body elements, the length of which is multiple times greater than a width and/or a height of the mold body element. The above-described method can be carried out particularly easily and reliably by way of a mold of this type.
Elements with an identical function and method of operation are provided in each case with the same designations in the figures.
With reference to
In addition to the embodiments which are shown, the invention permits further basic design principles. That is to say, the invention should not be considered to be restricted to the exemplary embodiments which are explained in relation to the figures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2022 105 501.9 | Mar 2022 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/053043 | 2/8/2023 | WO |
