Method for coating a shaped component

Abstract

The invention relates to a method for coating a shaped component (3) having an inner side (12) and an outer side (9) with a first coating material on the inner side (12) and with a second coating material on the outer side (9), wherein a strip (13) at least of the outer side (9) remains uncoated in the region of a circumferential edge (6) that adjoins the inner side (12) and the outer side (9), and the first and second coating materials cannot be mixed with each other, in which method the component (3) is introduced into a holder and held fixed in its position there while the coating materials are applied one after the other by means of a spraying robot. The method is simplified and allows a reduction in the number of handling steps in that a plate (1) is used as the holder, said plate having a recess (2) with profiling (4, 5) formed above the height thereof, into which the component (3) is placed without the use of a movable fastening means, and the recess (2) is sealed off in such a manner that the first coating material that is sprayed from a first side (7) of the plate (1) does not reach the outer side (9) of the component and the second coating material that is sprayed from the second side (8) of the plate (1) does not reach the inner side (12) of the component (3). The method is further characterized in that any overspray is extracted from the respective side and in that the second coating material is sprayed in such a manner that the strip (13) of the component (3) always lies in a spray shadow formed by the profiling (4, 5).

Claims

1. A method for coating a molded component comprising an interior and an exterior with a first coating material on the interior and with a second coating material on the exterior, wherein a strip at least of the exterior remaining uncoated in a region of a peripheral edge adjoining the interior and the exterior, and wherein the first and the second coating materials not being miscible with one another, comprising: introducing the molded component into a holder and holding said molded component fixed in position while the first and second coating materials are applied in succession by means of a spray robot, wherein a plate is used as the holder which comprises a recess with profiling formed over a height of the holder, wherein the component is inserted into the recess without the use of a mobile fastening means and thereby seals the recess in such a way that the first coating material sprayed on from a first side of the plate does not reach the exterior of the component and the second coating material sprayed on from the second side of the plate does not reach the interior of the component, and that any overspray from the first or second sides is extracted, and wherein spraying on of the second coating material proceeds in such a way that the strip of the component is always located in a spray shadow formed by the profiling.

2. The method as claimed in claim 1, wherein a spray arm of the spray robot comprises two lines and spray nozzles with which the first coating material and the second coating material are applied.

3. The method as claimed in claim 1, wherein the plate is oriented substantially horizontally, and wherein the first coating material is sprayed onto the component from a bottom as the first side of the plate and the second coating material is sprayed onto the component from a top as the second side of the plate.

4. The method as claimed in claim 1, wherein the component is optically transparent and wherein the first and second coating materials are used to form optically transparent coatings.

5. The method as claimed in claim 1, wherein the component is transparent to radiation from a source covered by the component and wherein the first and second coating materials form coatings transparent to radiation.

6. The method as claimed in claim 1, wherein the first coating material is an anti-fog coating material.

7. The method as claimed in claim 1, wherein the second coating material is a hard coat coating material.

Description

(1) The invention will be explained in greater detail below with reference to an exemplary embodiment illustrated in the drawings, in which:

(2) FIG. 1 is a schematic perspective representation of a plate serving as a holder, with two recesses, into one of which a component is inserted;

(3) FIG. 2 shows an arrangement for carrying out the method using the plate according to FIG. 1;

(4) FIG. 3 shows a section in the longitudinal direction of the recess in the plate with a component inserted into the recess;

(5) FIG. 4 is a representation according to FIG. 3 with a handling element for grasping the component.

(6) FIG. 1 shows a plate 1 comprising two recesses 2 for receiving a component 3. The plate has a given height H. The recesses 2 are formed at lateral margins with bevels 4, which develop at the lower margin into a step-like, peripheral bearing face 5, wherein the bearing face 5 has a profiled height contour, which is adapted to the shape of a lower edge 6 of the component 3. With the bevels 4 and the bearing face 5, the recess 2 thus forms profiling 4, 5 adapted to the component 3.

(7) The plate 1 is oriented substantially horizontally, but may form an acute angle preferably of less than 20 with the horizontal in order to receive the component 3 securely and hold it fixed owing to the weight of the component 3.

(8) The plate 1 comprises a bottom 7 as first side and a top 8 as second side. In the exemplary embodiment shown, the component 3 is placed onto the top 8 in such a way that it arches out towards the top 8, such that an exterior 9 of the component 3 projects at the top 8.

(9) The bearing face 5 is delimited by a steep edge 10 of the recess 2, which defines a passage opening 11 of the recess 2 towards the bottom 7. The passage opening 11 is thus open towards the bottom 7. An interior 12 (FIG. 3) of the component 3 may thus be coated with a spray jet through the passage opening.

(10) The bevels 4 are configured such that the entire exterior 9 of the component 3 may be coated with a spray jet from the top 8 of the plate 1. The spray jet may here be directed from a spray nozzle of a spray robot arm (not shown) onto the component 3 from all sides. The bevels 4 and optionally an edge falling steeply towards the bearing face 5 have the effect that a strip 13 of the exterior 9 adjoining the lower edge 6 of the component 3 remains uncoated, because the spray jet of the spray robot arm is directed such that the strip 13 always remains in the spray shadow of the bevel 4 and the step optionally formed towards the bearing face 5.

(11) The component 3 may in this case be coated on its exterior 9 with a spray jet from the top 8 of the plate 1, while the interior 12 of the arched component 3 may be coated with the spray jet from the bottom of the plate 1.

(12) FIG. 2 is a schematic illustration of a coating installation, with which the interior 12 is coated with a first coating material from the bottom 7 of the plate 1, the spray robot arm then being moved to the top 8 so as immediately thereafter to coat the exterior 9 of the component 3 with a second coating material.

(13) During coating from the bottom 7 with the first coating material, the overspray is extracted by an extraction device (not shown) located under the plate 1. Extraction is assisted by a partition wall arrangement 14, which delimits the extraction chamber at the back and sides. In conventional clean room technology, purge air is conducted by a roof arrangement 15 onto the top of the plate 1 and passed around the plate 1, such that it may be extracted from the bottom 7. During the process of spraying onto the bottom 7 overspray is immediately extracted downwards, while during the process of spraying onto the top 8 with the second coating material the spray particles are guided around the plate 1 and extracted at the bottom 7 of the plate 1, such that these particles also cannot come into contact with the interior 12 of the component 3.

(14) Contamination of the interior 12 with the second coating material or of the exterior 9 of the component 3 with the first coating material would have the consequence of disrupting subsequent coating of the other side, because the coating materials are incompatible, and therefore a homogeneous coating with the desired properties would not be obtained.

(15) FIG. 3 also shows that the bearing face 5 is adapted in contour to the profile of the lower edge 6 of the component 3, such that sealing is achieved by placing the component 3 onto the bearing face 5. Any gap remaining between the lower edge 6 and the bearing face 5 would not result in spraying through, because the gap is located in the spray shadow of the bearing face 5 when coating of the interior 12 proceeds from the bottom 7 of the plate 1 and because on the exterior 9 the strip 13 is located in the spray shadow of the profiling 4, 5 and therefore remains uncoated. Since it is not possible to spray through a small, hypothetical gap, passage of coating particles as a result of air guidance and extraction is not possible. Reliable coating both of the interior 12 and of the exterior 9 with the different coating materials is therefore ensured, despite the component 3 merely being laid on the bearing face 5 of the recess 2.

(16) FIGS. 3 and 4 show an insertion channel 16 at an end face of the component 3, which channel is sealed towards the bottom 7, for example by an inserted sheet metal part. A gripping element 17 may be introduced into the insertion channel 16, in order to grip the lower edge of the component 3 from below at the end face and thereby to lift the component 3 out of the recess 2 and for example place it on a belt which conveys the component 3 through a curing oven to cure the coatings. Alternatively, the component 3 may also be conveyed through a UV curing installation.

(17) Placing the component 3 onto the recess 2 in the plate 1 in accordance with the invention, in conjunction with the air guidance known from clean room technology, enables reliable and trouble-free coating of the interior 12 and of the exterior 9 with different, mutually incompatible coating materials, mobile fastening means and/or a second part of a holder being dispensed with.

(18) This enables very streamlined, reliable manufacture with extremely low handling effort.