Method for manufacturing a motor vehicle body

Abstract

A method for manufacturing a body (10) of a motor vehicle, wherein the body (10) is assembled from at least two large modules (11, 12, 13), in particular from at least one main module (11) and / or a front module (12) and / or roof module (13), comprising the following steps: Providing unpainted large modules (11, 12, 13). Applying a coating of an electrically non-conductive material by an additive manufacturing process to those sections of the large modules (11, 12, 13) where the large modules (11, 12, 13) are to be connected. Painting the coated large modules (11, 12, 13) by cathodic dip painting. Connecting the large modules (11, 12, 13) at the sections of the large modules (11, 12, 13) which at least partially bear the coating, wherein the connecting of the large modules (11, 12, 13) at the sections bearing the coating is done at least by bonding.The coating made of electrically non-conductive material includes an adhesive activator and / or an adhesive booster.

Description

[0001] The invention relates to a method for manufacturing a body of a motor vehicle according to the preamble of claim 1.

[0002] It is known in practice that a motor vehicle body is composed of so-called large modules. The large modules of a motor vehicle body include at least a main module and a front module, and preferably also a roof module. Optionally, the body may additionally have a rear module and side wall modules. Each large module can be composed of several submodules.

[0003] DE 10 2015 016 954 A1 discloses a motor vehicle body in modular construction. The modules are connected to each other at interfaces.

[0004] When the large modules to be joined are painted, for example via cathodic dip coating, connecting or joining the modules becomes difficult. Large modules cannot be joined together with sufficient quality at painted sections.

[0005] To ensure that painted large modules can still be joined with sufficient quality at the relevant sections, the usual practice is to mask the modules before painting, and then completely remove the masking afterwards. This is a time-consuming process.

[0006] DE 10 2018 210 982 A1 discloses the masking of an exterior component of a motor vehicle, wherein a masking layer is applied to a component surface. After a layer of paint has been applied to the vehicle component, the masking layer is completely removed.

[0007] US 2004 / 0238985A1 discloses a method for manufacturing and recycling masking agents used to mask areas of a vehicle during a painting process.

[0008] The subsequently published DE 10 2023 202 414 A1 discloses a method with the features of the preamble of claim 1.

[0009] DE 10 2022 204 779 A1 discloses a floor module to be connected to the body via an adhesive connection and a screw connection and to be used to mask contact surfaces of the floor module and / or the vehicle body during a surface coating process preceding the adhesive application.

[0010] DE 199 28 649 A1 and DE 10 2011 113 720 A1 reveal further state of the art.

[0011] There is a need to simplify the manufacturing of a motor vehicle body that is composed of several large modules.

[0012] The object of the invention is to create a novel method for manufacturing a motor vehicle body.

[0013] This problem is solved by a method according to claim 1.

[0014] The process comprises the following steps: Providing unpainted large modules. Applying a coating of an electrically non-conductive material to those sections of the large modules where they are to be connected, using an additive manufacturing process. Painting the coated large modules using cathodic dip coating. Connecting the large modules at the sections that still bear at least part of the coating, at least by bonding.

[0015] This process simplifies the production of a motor vehicle body assembled from large modules. A coating of an electrically non-conductive material is applied to the sections of the large modules where they are to be joined, using an additive manufacturing process. This coating is applied before the cathodic dip coating of the large modules. Unlike conventional masking methods, this coating is not removed after coating. Instead, it remains at least partially intact and completely present on the corresponding sections of the large modules after the cathodic dip coating process. The large modules are then joined at the coated sections, at least by bonding. Therefore, no further processing of the large modules is required after dip coating at the joints.Overall, the process for manufacturing a motor vehicle body composed of large modules can be simplified.

[0016] According to the invention, the coating made of the electrically non-conductive material comprises an adhesive activator and / or an adhesive booster. In particular, the adhesive activator and / or the adhesive booster is embedded in a microencapsulation that is ruptured by applying force when connecting the large modules, thereby releasing the adhesive activator and / or the adhesive booster. This is particularly preferred to facilitate the bonding of the large modules at the respective sections. An adhesive activator incorporated into the respective coating can initiate the bonding process between large modules to be joined. An adhesive booster incorporated into the respective coating can accelerate the curing of the adhesive during the joining of the large modules.

[0017] Preferably, the coating is applied using 3D printing. This allows the respective coating to be applied to the respective section of the respective large module in a particularly advantageous and simple manner.

[0018] Preferably, a multi-layer coating is applied to the sections of the large modules where the modules are to be connected. Applying a multi-layer coating is particularly preferred.

[0019] Preferably, if the coating consists of an electrically non-conductive material that dissolves or decomposes during cathodic dip coating, the thickness of the coating is dimensioned such that the coating only partially dissolves or decomposes during cathodic dip coating and the coating-bearing section of the respective large module is completely covered by the coating during and after dip coating.

[0020] In this context, a multi-layer coating may be designed so that an outer layer of the coating, consisting of an electrically non-conductive material, dissolves or decomposes during cathodic dip coating, releasing an underlying layer of another electrically non-conductive material comprising the adhesive activator and / or the adhesive booster, whereby this released layer comprising the adhesive activator and / or the adhesive booster does not dissolve or decompose during cathodic dip coating, or only partially dissolves or decomposes, so that the layer comprising the adhesive activator and / or the adhesive booster completely covers the coating-bearing section of the respective large module after dip coating.This method is preferred for joining the large modules together by bonding them at the sections bearing the respective coating after cathodic dip coating.

[0021] Preferred embodiments of the invention are set forth in the dependent claims and the following description.

[0022] An embodiment of the invention will be explained in more detail with reference to the drawing. The drawing shows: Fig. 1 an exploded view of large modules of a motor vehicle body, Fig. 2 a schematic section of a large module before cathodic dip coating of the same, Fig. 3 a large module in cathodic dip coating, Fig. 4 the schematic excerpt from a large module of the Fig. 2 after a cathodic dip coating of the same.

[0023] Fig. Figure 1 shows an exploded view of a motor vehicle body 10, which is composed of several large modules 11, 12, 13.

[0024] The large module 11 is in Fig. 1 is a so-called main module. The large module 12 is in Fig. 1 is a so-called front module. The large module 13 is in Fig. 1 around a so-called roof module.

[0025] The invention relates to a method for manufacturing a body 10 composed of large modules 11, 12, 13, wherein unpainted large modules 11, 12, 13 are first provided for this purpose.

[0026] A coating made of an electrically non-conductive material is applied to such sections of the large modules 11, 12, 13, at which the large modules 11, 12, 13 are to be connected, using an additive manufacturing process, preferably 3D printing.

[0027] Such large modules 11, 12, 13 are painted using a KTL process, i.e. cathodic dip painting.

[0028] After painting, the large components 11, 12, 13 are connected or joined together, at least by gluing, on the sections of the large modules 11, 12, 13 that still bear at least part of the coating.

[0029] It is therefore in accordance with the present invention to provide the large modules 11, 12, 13 with a coating on their fastening sections prior to cathodic dip coating, which is not removed after dip coating, but remains completely over the entire surface of the sections of the large modules 11, 12, 13 where they are connected, but possibly with a reduced thickness.

[0030] Accordingly, the inventive method differs fundamentally from masking, since the coating remains on the connecting sections of the large modules 11, 12, 13 and is therefore not completely removed.

[0031] Fig. Figure 2 shows a section of a large module 11, 12 or 13, with a section 14 designed as a projection of the in Fig. In the large modules 11, 12 and 13 shown in partial detail, a coating 15 made of an electrically non-conductive material is applied via 3D printing. Fig. 2. This coating is formed in 15 layers, wherein in Fig. 2 Both layers 16, 17 of the coating 15, each made of an electrically non-conductive material, are applied to section 14 of the large module 11, 12 and 13 respectively via 3D printing. In Fig. Figure 2 shows the large module 11, 12 or 13 before its cathodic dip coating.

[0032] Fig. Figure 3 shows one of the large modules, namely a front module 12, during cathodic dip painting in a dip bath 18, wherein according to Fig. 3 The front module 12 to be coated is connected to a cathode 19 and serves as a deposition electrode for cathodic dip coating. A counter electrode 21, connected to an anode 20, protrudes into the dip bath 18. The dip bath 18 contains an electrically conductive, aqueous dip coating, and a DC voltage field is applied between the front module 12 to be coated and the counter electrode 21 via the voltage source 22, which comprises the anode 20 and cathode 19. Through capillary processes, water from the dip bath 18 is almost completely forced out of the coating film. A coating 23 forms on the surface of the front module 12 to be coated as positively charged coating particles 24 are deposited on the front module 12.

[0033] Fig. Figure 4 shows the section of the Fig. 2 from the large module 11, 12, 13 after cathodic dip painting, wherein in the Fig. In the embodiment shown in Figure 4, the outer layer 16 of the coating 15 dissolves or decomposes during cathodic dip coating, releasing the underlying layer 17. In the illustrated embodiment, this layer 17 also includes the adhesive activator and / or the adhesive booster, wherein the adhesive activator and / or adhesive booster are encapsulated separately or together by a microencapsulation (not shown in detail). No coating 23 forms on the coating 15.

[0034] This layer 17 of the coating 15, released during cathodic dip coating, does not dissolve or only partially dissolves in thickness during cathodic dip coating, so that the layer 17 comprising the adhesive activator and / or the adhesive booster completely covers the coating-bearing section 14 of the large module 11, 12 or 13 after dip coating.

[0035] During the subsequent joining process, the large modules to be connected are glued together, with a force being applied to them during the bonding process. As a result of this force being applied during the joining of the large modules, the microencapsulation of the adhesive activator and / or adhesive booster is ruptured, thus releasing the adhesive activator and / or adhesive booster, allowing it to exert its effect as described above.

[0036] Although in Fig. 2 and Fig.While a multi-layer coating 15 is shown in Figure 3, a single-layer coating can also be used. This single-layer coating is then made of an electrically non-conductive material and comprises the adhesive activator and / or the adhesive booster. The coating 17 is designed either in such a way that it does not dissolve or decompose during cathodic dip coating, or at least only partially dissolves or decomposes in thickness, so that after dip coating the coating completely covers the corresponding section 14 of the respective large module 11, 12, 13.

[0037] The coating 15 can be applied immediately before the cathodic dip coating of the respective large module 11, 12, 13. It is also possible that supplier parts that are part of a large module 11, 12, 13 already have such a coating.

Claims

[1] Method for producing a body (10) of a motor vehicle, wherein the body (10) is assembled from at least two large modules (11, 12, 13), in particular from at least one main module (11) and / or one front module (12) and / or roof module (13), with the following steps: Providing unpainted large modules (11, 12, 13), Applying a coating of an electrically non-conductive material via an additive manufacturing process to those sections of the large modules (11, 12, 13) to which the large modules (11, 12, 13) are to be connected, Painting the large modules (11, 12, 13) provided with the coating via cathodic dip painting, Connecting the large modules (11, 12, 13) to the sections of the large modules (11, 12, 13) that still at least partially carry the coating, wherein the connecting of the large modules (11, 12, 13) to the sections that carry the coating is carried out at least by gluing characterized by , that the coating of the electrically non-conductive material comprises an adhesive activator and / or an adhesive booster. [2] Method according to claim 1, characterized by that the coating is applied using 3D printing. [3] Method according to claim 1 or 2, characterized by that the adhesive activator and / or the adhesive booster is embedded in a microencapsulation which is broken open by applying a force when connecting the large modules (11, 12, 13) with the release of the adhesive activator and / or the adhesive booster. [4] Method according to one of claims 1 to 3, characterized bythat a multi-layer coating is applied to the sections of the large modules (11, 12, 13) to which the large modules (11, 12, 13) are to be connected. [5] Method according to claim 4, characterized by that at least one outer layer of the coating consists of an electrically non-conductive material. [6] Method according to one of claims 1 to 5, characterized by that, if the coating consists of an electrically non-conductive material which dissolves or decomposes during the cathodic dip painting, the thickness of the coating is dimensioned such that the coating only partially dissolves or decomposes during the cathodic dip painting and the section of the respective large module (11, 12, 13) carrying the coating is completely covered by the coating during and after the dip painting. [7] Method according to claim 4 or 5 and according to claim 6, characterized bythat an outer layer of the coating, which consists of an electrically non-conductive material, dissolves or decomposes during the cathodic dip painting and releases an underlying layer made of a likewise electrically non-conductive material which comprises the adhesive activator and / or the adhesive booster, wherein this released layer comprising the adhesive activator and / or the adhesive booster does not dissolve or decomposes during the cathodic dip painting or only partially dissolves or decomposes, so that the layer comprising the adhesive activator and / or the adhesive booster completely covers the section of the respective large module (11, 12, 13) carrying the coating after the dip painting.

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