COATING EDGES USING A ROBOT

Abstract

Disclosed is an apparatus for at least partially, preferably entirely coating the peripheral edge of a workpiece, comprising a feeding device that has a coating head; a coating application means that applies the coating to the peripheral edge as well as an air flow are provided on/in the coating head, said air flow removing excess coating from the edge; the workpiece and the coating head are moved relative to one another. The invention further relates to a method for coating the peripheral edge of a workpiece with the aid of a coating head.

Claims

1. An apparatus for at least partially, coating a peripheral edge of a workpiece, having a coating apparatus which has a coating head, wherein the coating head has provided on/in it a coating-application means, which applies the coating to the peripheral edge, and wherein the coating head has a means for generating an air stream, wherein the means is a negative pressure, wherein the air stream removes excess coating from the peripheral edge, wherein the apparatus has a movement means which is configured such that the workpiece and the coating head are moved relative to one another, wherein movement takes place in at least two directions in space, wherein the coating application means and the means for generating the air stream can be operated separately from one another.

2. The apparatus as claimed in claim 1, wherein the coating head is provided such that a coating agent is injected from three or four sides, wherein in each case two nozzles are provided at an angle of about 45-to about 180 in relation to one another.

3. A method of coating a peripheral edge of a workpiece using the coating apparatus of claim 1, wherein at least one portion of the peripheral edge passes the coating head at least twice, wherein, during a first passage operation, a coating agent is applied to the workpiece and excess coating agent is removed by means of an air stream, wherein, during a second passage operation, coating agent is removed and/or distributed.

4. The method as claimed in claim 3, wherein process conditions which prevail in the coating head during the first passage operation are different from those which prevail during the second passage operation.

5. The method as claimed in claim 3, wherein relative movement between the workpiece and coating head during the first passage operation differs from that during the second passage operation.

6. The method as claimed in claim 3, wherein the movement means moves the workpiece and/or the coating head in at least two directions in space which are provided at an angle in relation to one another.

7. The method as claimed in claim 3, wherein the movement means rotates the workpiece.

8. The method as claimed in claim 3, wherein the movement means orients the workpiece prior to the latter being treated.

9. The method as claimed in claim 4, wherein relative movement between the workpiece and coating head during the first passage operation differs from that during the second passage operation.

10. The method as claimed in claim 4, wherein the movement means moves the workpiece and/or the coating head in at least two directions in space which are provided at an angle in relation to one another.

11. The method as claimed in claim 5, wherein the movement means moves the workpiece and/or the coating head in at least two directions in space which are provided at an angle in relation to one another.

12. The method as claimed in claim 4, wherein the movement means rotates the workpiece.

13. The method as claimed in claim 5, wherein the movement means rotates the workpiece.

14. The method as claimed in claim 6, wherein the movement means rotates the workpiece.

15. The method as claimed in claim 4, wherein the movement means orients the workpiece prior to the latter being treated.

16. The method as claimed in claim 5, wherein the movement means orients the workpiece prior to the latter being treated.

17. The method as claimed in claim 6, wherein the movement means orients the workpiece prior to the latter being treated.

18. The method as claimed in claim 7, wherein the movement means orients the workpiece prior to the latter being treated.

19. The method as claimed in claim 14, wherein the movement means orients the workpiece prior to the latter being treated.

20. The apparatus of claim 1, wherein the apparatus fully coats the peripheral edge of the workpiece.

Description

[0027] The inventions will be explained hereinbelow with reference to the figures. These explanations are given merely by way of example and do not limit the general concept of the invention. In the figures:

[0028] FIG. 1 shows a first embodiment of the apparatus according to the invention,

[0029] FIG. 2 shows a further embodiment of the apparatus according to the invention,

[0030] FIG. 3 shows an embodiment in which the coating apparatus is provided such that it can be moved relative to the industrial robot,

[0031] FIG. 4 shows an embodiment in which the coating apparatus is arranged on the industrial robot, and

[0032] FIG. 5 shows an embodiment of the method according to the invention.

[0033] FIG. 1 shows a first embodiment of the method according to the invention. The workpiece, which may be, for example, round or rectangular or of any desired shape and which may consist, for example, of metal, wood, plastics material or a combination thereof, is moved into the operating region of the movement means 2, in the present case designed in the form of an industrial robot, via an entry conveyor 1, for example an endless belt or a clamping apparatus, for example a chuck which is moved via a displacement apparatus. The arm of the industrial robot 2, in this example, is equipped with a first and a second lever, wherein the second lever is provided at the end of the first lever. It is possible to alter the angle of the two levers in relation to one another. Moreover, it is also possible to alter the angle of the first lever relative to the fastening of the industrial robot. The industrial robot is provided for movement as a whole about a vertically rotatable axis. It is preferably possible, in addition, for at least one of the levers, preferably both levers, to rotate about a longitudinal axis. Provided at the end of the second lever, in particular in an articulated manner, is a gripper, which is designed preferably in the form of a suction gripper which sucks firmly to the workpiece in order for the latter to be capable of being raised and moved without any alteration in the position of the workpiece relative to the gripper. The industrial robot grips the workpiece and orients it. As an alternative, the workpiece is already oriented when positioned at the end of the entry conveyor. The orientation by means of the industrial robot takes place either via measurement of the workpiece, for example above the entry conveyor, and/or by displacement of the workpiece, for example, by means of the industrial robot, against a defined stop, for example of the entry conveyor. Once the industrial robot has gripped the workpiece, it transports it for example to a coating-preparation station, for example a grinding station 3. A person skilled in the art will be aware that this coating-preparation station, nevertheless, need be present only as an option. The edge of the workpiece is then coated in a coating apparatus 4. This coating apparatus has a coating head, in which are present one or more coating nozzles which apply a coating agent, for example a lacquer, to the edge of the workpiece. The coating head preferably contains an air stream which is generated in particular by a negative pressure, which is present on the coating head, in order for excess coating material to be removed from the edge of the workpiece and/or for the coating agent to be distributed over the peripheral edge. During the coating operation, preferably the workpiece moves relative to the coating head, which is in a fixed location during the coating operation. It is preferably the case that the entire peripheral edge of the workpiece is coated. For this purpose, the industrial robot rotates the workpiece preferably about a vertical axis of rotation during the coating operation. As an alternative, or in addition, it is also possible, however, for the coating apparatus to be moved relative to the workpiece. Once the peripheral edge has been provided, at least in part, with a coating agent, the industrial robot transports the workpiece to a drying unit 5. It is also the case during the drying operation that the industrial robot moves the workpiece in particular relative to the preferably fixed-location drying unit. As an alternative, or in addition, it is also possible, however, for the drying unit to be moved relative to the workpiece. Depending on the surface-related requirements, the treatment can be repeated. Once the coating has been dried, at least in part, the workpiece is optionally transported, once again by the industrial robot, to an exit conveyor 6, which moves the workpiece out of the operating region of the robot.

[0034] It is possible for the treatment stations either to face away from the robot or to be arranged around the foot of the robot.

[0035] The coating head is preferably of comparatively narrow design. In particular, its extent parallel to the movement direction of the workpiece is less than 20 mm. The coating agent is preferably injected into the coating head from 3 or 4 sides, wherein in each case two nozzles are provided preferably at an angle of 45-180 in relation to one another.

[0036] The dryer may be, for example, a UV dryer or an IR dryer. However, it is possible to provide for a plurality of dryers, which can be activated independently of one another. The UV lamps are, for example, gallium and/or mercury UV lamps.

[0037] A person skilled in the art will be aware that a workpiece can enter a treatment station a number of times. For example, an operating sequence may be as follows: [0038] The workpiece is placed in position [0039] The workpiece is conveyed into the operating region of the industrial robot [0040] The workpiece is accommodated and/or oriented by the industrial robot [0041] At least one edge, preferably the entire peripheral edge, of the workpiece is ground [0042] At least one, preferably the entire, peripheral edge of the workpiece is lacquered [0043] The coated edges are dried [0044] The workpiece is set down on the exit conveyor [0045] The tool is conveyed out.

[0046] An operating sequence in which the edges are lacquered twice may be, for example, as follows: [0047] The workpiece is placed in position [0048] The workpiece is conveyed into the operating region of the industrial robot [0049] The workpiece is accommodated and oriented, for example by the industrial robot [0050] At least one edge, preferably the entire peripheral edge, is ground [0051] At least one sub-region, preferably the entire peripheral edge, is lacquered [0052] The coated regions are dried [0053] At least one sub-region, preferably the entire of the peripheral edge, is ground [0054] At least one sub-region, preferably the entire peripheral edge, is lacquered [0055] The newly coated region of the peripheral edge is dried [0056] The workpiece is set down on the exit conveyor [0057] The workpiece is conveyed out.

[0058] FIG. 2 shows a further embodiment of the apparatus according to the invention. In comparison with the embodiment according to FIG. 2, the present embodiment provides two industrial robots 2, which may be of identical or different design. A set-down and/or transporting means 7 is preferably located between the two industrial robots. In the case of the present embodiment, the cycle time for treating a workpiece may be divided up between 2 industrial robots. For example, the first industrial robot transports the workpiece during the preparatory step, in this case the grinding operation. The second industrial robot moves the workpiece as it is being coated and/or dried. It is possible to provide, between the two industrial robots, an additional set-down or transporting means 7, on which the workpieces are set down after being coated, and/or prior to being coated, and/or on which the workpieces are set down and/or transported after being coated, so that they can be fed anew to lacquering preparation. A person skilled in the art will be aware that it is also possible for more than two industrial robots to be present.

[0059] FIG. 3 shows a further embodiment of the apparatus according to the invention. In the present case, for example the coating apparatus, the coating-preparation unit 3 and/or the drying unit are/is provided for movement relative to the operating region 8 of the robot.

[0060] These stations are moved prior to and/or during the respective treatment operation. The movement of one or more of the stations 3-5 has, in particular, the advantage that workpieces of different sizes can be adapted to the operating region of the industrial robot.

[0061] FIG. 4 shows an embodiment of the apparatus according to the invention in which the coating head 4 is provided on the arm of the industrial robot. A person skilled in the art will be aware that it is also possible for the coating-preparation unit 3 and/or the drying unit 5 to be provided on the robot arm. In the present case, the workpiece 9 is fixed in location and/or is moved by a transporting means 10, in this case 2 conveyor belts, during the coating operation. It is also possible, however, for the transporting means 10 just to serve for transporting the workpiece 9 into the operating region of the industrial robot.

[0062] FIG. 5 shows the operations of lacquering, grinding and drying a workpiece. FIG. 5a illustrates the operation of lacquering the workpiece. It is clearly evident that first of all the peripheral edge 9a, then the peripheral edge 9b, thereafter the peripheral edge 9c and finally the peripheral edge 9d are lacquered. The pump, which supplies the nozzles with coating agent, is activated during this lacquering operation. As illustrated by the arrow, the workpiece is rotated in the counterclockwise direction during the lacquering operation. As an alternative, or in addition, it is also possible for the workpiece to be at a standstill and for the coating head to move. Before, as soon as and/or after the point of the peripheral edge where lacquering started is located once again in the coating head, the lacquering nozzles are deactivated, but the workpiece continues to be transported, as indicated by the arrow 12, along the coating head. As a result, in particular coating material in the form of a double coating is removed and/or distributed over the adjacent regions so as to avoid the formation of any build-ups of lacquer. This is achieved by the air stream in the coating head, said air stream being produced preferably by the negative pressure applied.

[0063] For the case where the component is a round one, the workpiece, following a 360 rotation, is rotated further in the same direction and, in the process, drawn slowly out of the coating head. The workpiece thus performs, in part, a spiral movement. The distance between the axis of rotation of the workpiece and the coating head increases. The air stream in the coating head here remains active and preferably increases. As a result, coating material in the region where double lacquering has taken place is distributed, in particular, over the adjacent region and therefore this region where double lacquering has taken place is smoothed.

[0064] As can be gathered from FIG. 5b, during the grinding operation, the workpiece is likewise rotated about an axis of rotation, which is illustrated by the arrow. The peripheral edge is ground throughout the rotation. As soon as the region of the peripheral edge has been ground in its entirety, the industrial robot removes the workpiece from the grinding means.

[0065] The same applies to the drying operation (FIG. 5c). Here too, as illustrated by the arrow, the workpiece is rotated relative to a dryer. The coating material applied to the peripheral edge dries.

LIST OF REFERENCE SIGNS

[0066] 1 entry conveyor

[0067] 2 movement means, industrial robot

[0068] 3 pre-treatment means, grinding means, grinding brush

[0069] 4 coating apparatus, application chamber

[0070] 5 dryer, UV dryer, IR dryer

[0071] 6 exit conveyor

[0072] 7 set-down and/or transporting means

[0073] 8 operating region of the movement means 2

[0074] 9 workpiece

[0075] 9a-d edge portion, peripheral-edge portions of the workpiece

[0076] 10 conveying means

[0077] 11 coating phase

[0078] 12 smoothing phase