COATING METHOD AND CORRESPONDING COATING INSTALLATION

Abstract

A coating method for coating components, e.g. motor vehicle bodywork components in a painting installation, is provided. The coating method includes moving an application device over a component surface to be coated along a pre-determined coating path , and applying a coating medium stream onto the component surface by means of an application device. The coating medium stream is not rotationally symmetrical relative to its stream axis and therefore generates on the component surface an elongate spray pattern with a particular longitudinal direction. The method further includes rotation of the application device about the stream axis relative to the coating path during the movement of the application device so that the angular position of the longitudinal direction of the spray pattern relative to the path transverse direction changes along the coating path.

Claims

1-12. (canceled)

13. A method for coating components, comprising: moving an application device along a pre-determined coating path over a component surface to be coated, applying a coating medium stream with the application device onto the component surface while the application device is moved over the component surface, wherein the coating medium stream is rotationally asymmetrical relative to its stream axis and generates on the component surface an elongate spray pattern with a longitudinal direction, and rotating the application device about the stream axis relative to the coating path during the movement of the application device along the coating path, wherein rotation of the application device changes the angular position of the longitudinal direction of the spray pattern relative to a path transverse direction.

14. The method according to claim 13, wherein the application device is rotated about the stream axis through a rotation angle between the longitudinal direction of the spray pattern and the path transverse direction in order to achieve a desired path width, the application device is moved at a movement speed along the coating path, the application device applies the coating medium with a coating medium flow, at least one of the movement speed and the coating medium flow is adjusted dependent upon the rotation angle to provide a desired coating layer thickness.

15. The method according to claim 14, wherein the adjustment of the movement speed of the application device dependent upon a current rotation angle of the application device is carried out in accordance with the formula:
V(α)=V0/cos(α) where V0 is the movement speed of the application device when the rotation angle between the longitudinal direction of the spray pattern and the path transverse direction is zero, α is the current rotation angle between the longitudinal direction of the spray pattern and the path transverse direction, V(α) is the adjusted movement speed at the current rotation angle.

16. The method according to claim 13, wherein the component surface is nonrectangular, the coating medium is applied along a plurality of coating paths on the component surface, and during the movement along the coating paths, the application device is rotated about the stream axis in order to rotate the elongate spray pattern such that a desired path width is achieved.

17. The method according to claim 13, wherein the application device is moved by a multi-axis application robot over the component surface, the operation of the application device and of the application robot is controlled by a parameter set, and the parameter set is adjusted during the movement of the application device along the coating path.

18. The method according to claim 17, wherein the parameter set comprises at least one of the following parameters for controlling the application device and the application robot: a movement speed of the application device along the coating path, an acceleration of the application device along the coating path, a rotation angle of the application device between the longitudinal direction of the spray pattern and the path transverse direction, a rotation speed of the application device, a coating medium flow, and a coating spacing between the application device and the component surface.

19. The method according to claim 17, wherein the parameter set for controlling the application device and the application robot along the coating path is continuously adjusted.

20. The method according to claim 17, wherein the coating path is subdivided into a plurality of successive path portions situated one after another, and wherein the parameter set for controlling the application device and the application robot is kept constant within the individual path portions and is adjusted between the path portions.

21. The method according to claim 13, further comprising: determining a desired width of the coating path, and determining a rotation angle between the longitudinal direction of the spray pattern and the path transverse direction corresponding to the desired width of the coating path with the following formula:
α=arccos(SB2/SB1), where SB1 is a width of the spray pattern along the longitudinal direction of the spray pattern, SB2 is the desired width of the coating path, α is the rotation angle between the longitudinal direction of the spray pattern and the path transverse direction.

22. The method according to claim 13, wherein the application device is continuously rotated during the movement along the coating path.

23. The method according to claim 22, wherein the spray pattern is sharp-edged.

24. The method according to claim 23, wherein the spray pattern is substantially rectangular.

25. The method according to claim 23, wherein the application device is moved along a plurality of coating paths across the component surface, and at least one of the coating paths is curved.

26. The method according to claim 22, wherein he application device is guided over the component surface such that the coating medium stream is oriented substantially perpendicularly to the component surface at the interface therebetween.

27. A coating installation comprising: an application device configured to apply a coating medium stream onto a component surface, wherein the coating medium stream is rotationally asymmetrical relative to its stream axis and generates on the component surface an elongate spray pattern with a longitudinal direction, an application robot configured to guide the application device along a pre-defined coating medium path over the component surface, and a robot control system configured to control the application robot, wherein the robot control system rotates the application device about the stream axis during the movement along the coating path, so that a rotation angle between the longitudinal direction of the spray pattern and the coating path changes along the coating path.

28. The coating installation according to claim 27, wherein: the robot control system controls the application robot such that the application device is moved at a movement speed along the coating path over the component surface, and the robot control system adjusts the movement speed of the application device dependent upon the rotation angle between the longitudinal direction of the spray pattern and the path transverse direction.

Description

DRAWINGS

[0075] The present disclosure is further explained below in the description, making reference to the drawings. In the drawings:

[0076] FIG. 1 shows a plan view onto a roof of a motor vehicle bodywork, wherein the roof is to be painted,

[0077] FIG. 2 shows a schematic representation of adjacent painting paths for painting the roof of the motor vehicle bodywork of FIG. 1 in the lower region of FIG. 1,

[0078] FIG. 3 shows a modification of FIG. 2,

[0079] FIG. 4 shows a schematic representation of a transition portion of a painting path,

[0080] FIG. 5 shows a modification of FIG. 4,

[0081] FIG. 6 shows a schematic representation of a painting installation according to the present disclosure,

[0082] FIG. 7 shows a schematic representation of painting with parallel painting paths according to the prior art, which leads to uncoated regions, and

[0083] FIG. 8 shows a schematic representation of adjacent painting paths with overlaps between the adjacent painting paths according to the prior art.

DESCRIPTION

[0084] FIGS. 1 and 2 show a schematic representation of painting an exemplary vehicle component, a roof 9 of a motor vehicle bodywork by an application device which generates an approximately rectangular spray pattern 2, as shown in FIG. 2.

[0085] The painting of the roof 9 is configured to accommodate curved side edges 10 of the roof 9. It is therefore not possible simply to paint the roof 9 with parallel coating paths 1, since this would lead to uncoated regions 6 (see FIG. 7) or to overcoated regions 8 (see FIG. 8).

[0086] According to the present disclosure, the application device is rotated along the path course 3, specifically about the stream axis of the applied coating medium stream, so that the spray pattern 2 rotates accordingly. Thus, FIG. 2 shows a rotation angle a between the longitudinal direction 11 of the elongate spray pattern 2 and a path transverse direction 12, wherein the path transverse direction is oriented perpendicularly to the path course 3 in each case. From FIG. 2, it is apparent that the rotation angle a of the spray pattern 2 is adjusted along the path course 3 in order to adapt the path width so that the coating paths 1 abut one another without gaps and without overlaps and thereby conform to the component edges 10.

[0087] FIG. 3 shows a modification of FIG. 2 with another adjustment of the rotation angle a along the path course 3. Herein, however, the whole roof 9 is painted without overlaps and without gaps between the adjacent coating paths 1.

[0088] FIG. 4 shows a schematic representation of the transition from one path portion 13 with a maximum path width SB1 to a path section 14 with a substantially smaller path width SB3.

[0089] Situated herein between the two path portions 13, 14 is a transition portion 15 with a path width SB2 which is adjusted from a value SB2=SB1 at the start of the path portion 15 to a value SB2=SB3 at the end of the transition portion 15.

[0090] For this adjustment of the path width SB2, the spray pattern 2 is rotated in each case, as shown in FIG. 4, wherein different rotation angle states are shown along the path course 3.

[0091] In the transition portion 15, not only one change of the rotation angle α2=α1=0° to α2=α3 takes place. Furthermore, in the transition portion 15, the movement speed of the application device along the path course 3 is also adjusted. It is thereby achieved that the layer thickness remains uninfluenced by the change of the rotation angle a between the path portion 13 and the path portion 14. Thus, the movement speed V3 in the path portion 14 is calculated dependent upon the movement speed V1 in the path portion 13 and the rotation angle α3 in the path portion 14 according to the following formula:

V3=V1/cos(α3).

[0092] In the transition portion 15, the application device therefore undergoes an acceleration a2, which is calculated as follows:

a2=(V3−V1).sup.2/S2,

wherein S2 is the length of the transition portion 15 along the path course 3.

[0093] In the transition portion 15, the application device—and thus also the spray pattern 2—is rotated at a rotation speed ω2 which depends on the layer thickness tolerance ΔSD %, the movement speed V1 in the path portion 15 and the path width SB1 in the path portion 13 and can be calculated according to the following formula:

ω2=V1/SB1.Math.ΔSD %.Math.360°/π.

[0094] FIG. 5 shows a modification of FIG. 4 so that for the avoidance of repetition, reference is made to the above description. A peculiarity herein lies therein that the path course 3 is not exactly linear, but undergoes a lateral offset in the transition portion 15.

[0095] Finally, FIG. 6 shows, in a schematic form, a painting installation according to the present disclosure to carry out the painting method according to the present disclosure as described above.

[0096] The painting installation includes a multi-axis painting robot 16 which can be realised in a conventional manner and therefore need not be described in greater detail.

[0097] The painting robot 16 is controlled by a robot control system 17 wherein the robot control system 17 also controls an application device 18 which is positioned in front of the painting robot 16. The robot control system 17 controls the painting robot 16 such that the application device 18 is guided in adjacent coating paths over a component surface 19 to be painted, as described in detail above.

[0098] In this movement of the application device 18, the robot control system 17 controls the painting robot 16 such that the application device 18 can be rotated about a stream axis 20 of the coating medium stream in order to be able to adapt the path width of the applied coating path, as previously described in detail above.

[0099] The present disclosure is not restricted to the above-described exemplary implementations. Rather a plurality of variants and modifications is possible which also make use of the present disclosure.