Method for manufacturing a front-plated operating, decorative or display element with uncoated areas

Abstract

Method for manufacturing a front-plated operating, decorative or display element with uncoated areas, comprising the following process steps: a) Manufacturing a base body from a transparent, translucent, or colored electroplatable plastic material with a front and a back side, b) Covering or shielding an area of ​​the back side to prevent electroplating in that area; c) Applying a mask to the front side parallel to the aforementioned area, d) Holding and contacting the base body on the surface of the electroplatable material, wherein the contacting takes place outside the area and masking, e) chemical and optionally electroplating pretreatment of the base body by a colloidal or ionic process or by direct metallization to produce a thin-film metal layer outside the area and electroplating to complete the metallic surface coating, characterized by that the masking is done by means of a plastic layer applied using a processor-controlled melting device and that openings are created through a multi-layered structure, enabling cross-contacting.

Description

[0001] The invention relates to a method comprising the process steps specified in the preamble of claim 1. Such a method is known from German patent application DE 10 2007 015 625 A1.

[0002] The automotive industry, in particular, is increasingly using real materials as surface materials, some of which are also illuminated. Galvanized metal surfaces are used especially for buttons within switch panels or for individual switches; these surfaces have cutouts through which light is directed for functional and ambient lighting.

[0003] Keys manufactured using a two-component process are known in this regard. In this process, a base body, for example made of polycarbonate (PC), is injection-molded. This base body has raised areas on the visible side that correspond to the symbols or clearances to be displayed. It is then overmolded with a second component made of a galvanizable material, such as acrylonitrile butadiene styrene (ABS) or PC / ABS, leaving the end faces of the raised areas unmolding. Injection molding of a preform made of PC / ABS or styrene, or back injection molding with PC, is also possible. After this pretreatment, the component undergoes an electroplating process. In this process, metal layers are deposited only on the galvanizable material, not on the polycarbonate body.

[0004] In another process, described in German patent DE 102 08 674 B4, a pre-molded polycarbonate part is overmolded with a plating-compatible material such as PC / ABS or ABS and then nickel-plated. The nickel layer is then removed using a laser where symbols or clearances are required. The plating process is then continued with chrome plating. Where no nickel remains, no chrome layer is formed. This makes the material translucent in the uncoated areas.

[0005] In addition to laser cutting, a material removal process, the previously mentioned DE 10 2007 015 625 A1 proposes a method in which the areas to be exposed or kept clear are created using an additive process. In this process, the areas to be exposed are kept clear by means of a varnish applied using a printing process. The specific printing process mentioned is screen printing.

[0006] Such traditional printing methods are relatively expensive to set up and not very flexible when molded parts with different symbol representations are required. Therefore, these printing methods are only economically viable for items produced in high volumes.

[0007] The task therefore arose to improve this process in such a way that it is particularly cost-effective and flexible in its application.

[0008] This problem is solved according to the invention by means of masking by means of a plastic layer which is applied by means of a processor-controlled melting device and by creating openings through a multi-layer structure through which cross-contacting is made possible.

[0009] A processor-controlled plastic printer preferably serves as the melting device. Such plastic printers are currently used for the manufacturing process known as FDM (Fused Deposition Modeling) in the field of rapid prototyping, in which a workpiece is built up layer by layer from a meltable plastic.

[0010] Advantageously, several plastic components can also be processed, since plastic printers generally have several printheads that can be supplied with different plastics and especially with differently colored plastics.

[0011] The proposed method is extremely flexible, as the shape of the plastic coating to be applied is determined solely by software and can therefore be changed from one workpiece to another without interrupting the printing process. This also eliminates the costly changeover times required for exchanging printing plates in conventional printing techniques.

[0012] The printhead(s) of the plastic printer have heating elements that liquefy one or more different plastics, press them through a nozzle arrangement, and melt them onto a surface with high resolution to create a graphic representation.

[0013] Plastic printing advantageously requires no additional curing processes because the print immediately possesses its material-specific properties upon solidification. The process is very precise and allows for the creation of symbols ranging from coarse to extremely fine. Through one- or two-dimensional relative movements between the print head and the substrate, even larger areas can be coated with a graphically structured plastic layer. Both simple surfaces and symbolic representations can be printed.

[0014] The printing method is highly flexible thanks to the digital printing process. Any font and font size stored in the plastic printer's control unit can be used. Even the printing of three-dimensional symbols is easily possible.

[0015] Plastic printing allows for the production of both solid-color and transparent surfaces. Depending on the desired color effect, both colored and semi-transparent plastics can be used. This also makes it possible to adjust the thickness to match the layer thickness of the subsequent metallic surface coating (e.g., chrome plating).

[0016] The versions to be metallized then undergo an electroplating process in which the components are pickled and metallized, preferably nickel-plated, copper-plated, and chrome-plated. The plastic-printed areas are not affected by the pickling process. Therefore, no metallic layers build up in the printed areas during the electroplating process. If the plastics used are translucent or transparent, they are light-transmitting.

[0017] Another advantage is that no parts need to be removed from the electroplating process for laser cutting or other methods of nickel removal. Larger lettering widths or areas can be removed, which would take a very long time with laser cutting due to the low ablation rates. The same applies to a two-component process, although here no complex tools with cutouts or slides need to be created.

[0018] The process also allows for the creation of vertical vias (openings, bores). In a first step, a symbol, such as the letter O, is left unprinted in a section. Depending on the size of this section, a substructure is created using a material that closes the remaining outline of the O. A further layer is then applied, now representing the complete O. If the unprinted section is large enough to require a support structure, this is washed out in a subsequent water purification process. This "bridge" is not visible to the naked eye. When this component is then subjected to a conventional electroplating process, an electrical connection is established because the upstream electrolyte baths create an electrically conductive bond within these openings.The subsequent electroplating baths deposit corresponding metal layers where an electrical connection has been established. Thus, a closed symbol is visible externally.

[0019] Overall, the proposed manufacturing process is very cost-effective because it requires significantly fewer manual steps compared to known methods. In known methods, for example, the components are removed from the interrupted electroplating process, disassembled from the racks, laser-treated, and then remounted on the rack. Afterward, the components are returned to the electroplating process and further processed. Such steps are completely eliminated in the method according to the invention.

[0020] Furthermore, it is possible to carry out the printing processes for finished parts immediately after the injection molding process. The components can thus be inserted into the plastic printer manually or automatically. They can then be printed and subsequently transported in packaging to the electroplater.

[0021] If highly precise symbol placement or contour sharpness is required, the printed area can be smoothed at the edges using a laser ablation process. This process can also be carried out before electroplating. Since only the contours and not the surfaces are treated, this step is insignificant in terms of time but contributes to higher precision.

Claims

[1] Method for producing a front-coated operating, decorative or display element with uncoated areas, comprising the following process steps: a) Manufacturing a base body from a transparent, translucent, or colored electroplatable plastic material with a front and a back side, b) Covering or shielding an area of ​​the back side to prevent electroplating in that area; c) Applying a mask to the front side parallel to the aforementioned area, d) Holding and contacting the base body on the surface of the electroplatable material, wherein the contacting takes place outside the area and masking, e) chemical and optionally electroplating pretreatment of the base body by a colloidal or ionic process or by direct metallization to produce a thin-film metal layer outside the area and electroplating to complete the metallic surface coating, characterized by , that the masking is done by means of a plastic layer applied using a processor-controlled melting device and that openings are created through a multi-layered structure, enabling cross-contacting. [2] Method according to claim 1, characterized by that the covering or shielding is done with a plastic. [3] Method according to claim 1, characterized by that the covering or shielding is achieved by back-injection with a non-galvanizable plastic. [4] Method according to claim 1, characterized bythat the melting device has mechanical components of an inkjet printer. [5] Method according to claim 1, characterized by that the melting device is controlled by a personal computer. [6] Method according to claim 1, characterized by , that the base body is formed by a galvanizable film that is back-injected with a plastic. [7] Method according to claim 6, characterized by that the film is deformed through a deep-drawing process. [8] Method according to claim 1, characterized by , that the edge areas of the plastic layer are smoothed using a laser ablation process.