EP3377231B1 - Coating method and corresponding coating system - Google Patents

Description

The invention relates to a coating method for coating a component with a coating agent, in particular for painting motor vehicle body components or aerospace components in a painting system. The invention further comprises a corresponding coating system.

When painting motor vehicle bodies or aerospace industrial components, there is sometimes a need to paint different parts of the motor vehicle body with different colors. For example, it may be desirable to paint the roof of a motor vehicle body in a different color than the rest of the motor vehicle body.

If a rotary atomizer is used as an application device, the motor vehicle body must be painted twice in succession with the desired color in such a contrast coating. In the second painting process, those surface areas of the motor vehicle body that are not painted with the new paint must then be masked. This masking of the motor vehicle body is complex.

Furthermore, it is from the prior art (e.g. DE 10 2013 002 433 A1 , DE 10 2013 002 413 A1 , DE 10 2013 002 412 A1 , DE 10 2013 002 411 A1 ) known to use application devices and application processes that have a narrowly limited jet of coating agent deliver and therefore enable a sharp edge coating or painting.

This mask-free, edge-sharp coating described in the abovementioned prior art does not produce any paint or coating agent losses through overspray. Such resource-saving methods are advantageous for a large number of applications, such as for coating processes.

The deliberate and advantageous sharpness of the paint web produced by such applicators requires a much higher accuracy of the switch-on and switch-off locations compared to atomizing applicators.

When using such application devices for painting motor vehicle bodies with contrasting colors, there is a need for the coating agent jet to be switched on or off at certain switching points. When changing from an area that is not to be painted to an area to be painted, the coating agent jet must be switched on at the boundary between the two areas. Conversely, the coating agent jet must be switched off during the transition from an area to be painted to an area that is not to be painted at the boundary between the two areas. It is therefore known from the prior art to program certain switching points on the component surface of the motor vehicle bodies to be painted, at which the coating agent jet is switched on or off. These switching points are usually programmed on the basis of predetermined CAD data (CAD: Computer Aided Design) of the respective motor vehicle body.

The problem here is the fact that in practice spatial deviations can occur between the actually desired switching points on the one hand and the switching points realized in practice on the other hand.

A possible cause for such deviations between the desired switching points on the one hand and the switching points that are implemented in practice on the other hand is a deviation of the real external shape of the motor vehicle body from the specified CAD data.

Another possible cause for such deviations is the signal propagation times from the robot control to the coating agent valve, which releases or blocks the coating agent jet. For example, a robot controller can have a cycle time of a control cycle of 4 ms, which at a travel speed of 1000 mm / s, for example, leads to a travel path of 4 mm, for example, this travel path also being able to add up over several control cycles of the robot controller. This signal transit time from the robot controller to the coating agent valve leads to a delayed switching process and thus to a shift of the actual switching point compared to the desired switching point.

Another possible cause for deviations between the desired switching points on the one hand and the switching points which have been implemented in practice, on the other hand, is the positioning of the motor vehicle body along the painting line, since this positioning is not carried out with absolute precision. Thus, the motor vehicle bodies to be painted are conveyed by a conveyor along the painting line through the painting system, the conveyor having a certain positioning inaccuracy. This positioning inaccuracy leads to a corresponding spatial deviation between the desired switching points on the one hand and the practically realized switching points on the other hand without suitable compensation.

The spatial deviation between the desired switching points on the one hand and the switching points which are implemented in practice on the other hand is associated with various disadvantages.

For example, the programmed switching points must be brought forward to achieve a perfect coating result, so that a sufficient coating is achieved in practice, even taking into account a possible shift in the switching point.

In addition, switch-on and switch-off times can occur in practice, which are not always exactly reproducible, since the signals from the robot controller do not always switch in the same control cycle.

There is also a risk of undercoating if, for example, the switch-off point is too early due to an error.

Out US 2012/0 219 699 A1 A coating method is known in which the component to be coated is measured on a camera basis in order to detect the exact relative position of the component to be coated in relation to the application device. However, a definition of switching points is not known from this. The reference markings on the component surface are used exclusively for measuring the relative position of the component to be coated in relation to the application device.

In addition, reference should also be made to the general technical background US 2001/0036512 A1 .

For the general technical background of the invention, reference should also be made to D2 ( DE 10 2012 005650 A1 ), D3 ( EP 2 644 392 A2 ), D4 ( EP 2 208 541 A2 ), D5 ( DE 10 2010 019612 A1 ) and D6 ( U.S. 4,783,977 A. ). Finally revealed DE 10 2007 020287 A1 a coating method according to the preamble of claim 1 and a coating system according to the preamble of claim 10. Here, switching markings are generated on the component surface in order to mark the switching points. The switching markings are detected by an optical sensor. However, the generation of the switching markings is complex and inflexible.

The invention is therefore based on the object of providing a correspondingly improved coating method and a correspondingly improved coating system.

This object is achieved by a coating method or a coating system according to the subclaims.

The coating method according to the invention initially provides, in accordance with the prior art, that an application device is moved over a component surface of the component to be coated (e.g. motor vehicle body component), in particular by means of a multi-axis coating robot with serial kinematics, the application device preferably along a programmed paint path is moved over the component surface. However, the applicator can also be guided over the component with another single-axis or multi-axis movement device.

Furthermore, in accordance with the prior art, the coating method according to the invention provides that the application device emits at least one coating agent jet of a coating agent (for example paint) onto the component surface to be coated, while the application device is moved over the component surface.

In the case of the coating method according to the invention, certain switching points are defined on the component surface to be coated, at which a switching action is to be triggered, such as switching on or switching on Switching off the at least one coating agent jet.

During the movement of the application device over the component surface, the desired switching action (e.g. switching on or switching off the at least one coating agent jet) is then carried out when a switching point is reached.

In the known coating method described at the beginning, the switching points on the component surface are only programmed and are therefore not visible on the component surface itself. This leads to the problems described above, since the actual switching points can differ spatially from the programmed switching points.

The invention solves this problem in that the programmed switching points are marked on the component surface by switching markings, the individual switching markings each corresponding to a switching point.

When the application device moves over the component surface, it is continuously checked whether a switching mark is reached. When a switching marking is detected, the desired programmed (expected) switching action (e.g. switching on or switching off the coating agent jet) is then carried out.

According to the invention, the switching markings are optical switching markings which are generated by means of a light source, in particular by means of a laser or a laser diode. For this purpose, the light source emits a suitable light marking (e.g. light point, light line) on the component surface in order to mark the switching point with a corresponding switching marking.

The optical switching markings on the component surface are recorded using an optical sensor (e.g. camera, CCD sensor).

In the preferred embodiment of the invention, the application device is moved over the component surface by a multi-axis coating robot with serial robot kinematics, which is known per se from the prior art and is therefore not described in more detail.

The movement of the coating robot is controlled by a robot controller, which is also known per se from the prior art.

In contrast, the generation of the switching markings, the detection of the switching markings and / or the switching on and switching off of the application device is preferably not controlled by the robot controller but by a switching point control.

This division of tasks between the robot control on the one hand and the switching point control on the other hand is advantageous because the dynamic response of the switching point control and thus the speed of the response to the switching markings is not limited by the duration of the control cycle of the robot control. The robot controller can work with a control cycle of, for example, 4 ms, since this control cycle is sufficiently short for the movement of the application device. The switching point control, on the other hand, can work with a shorter control cycle in order to enable the fastest possible response to the detected switching markings. This prevents unwanted when recognizing the individual switching markings Switching delays occur between the detection of the switching mark and the execution of the switching action (e.g. switching on or switching off the coating agent jet). In one variant of the invention, the switching point control is integrated in the robot control. For example, the switching point control on the one hand and the robot control on the other hand can be implemented as separate software modules or as separate hardware modules in a common control unit.

In another variant of the invention, however, the switching point control is separated from the robot control, i. H. the two controls are not arranged in a common control unit. Here, too, the switching point control on the one hand and the robot control on the other hand can be implemented as separate hardware modules or as separate software modules.

It has already been mentioned above that the desired switching points on the component surface by means of optical switching markings which are irradiated onto the component surface by means of a light source, for example by a laser. These switching markings are preferably generated on the component surface taking into account CAD data of the component to be coated, the CAD data reflecting the spatial shape of the component. In addition, the spatial position of the component to be coated is preferably determined, for example by reading out a belt encoder on the conveyor of the painting line. The spatial position of the switching markings on the component surface is then determined as a function of the CAD data and as a function of the spatial position of the component to be coated.

Furthermore, there is the possibility within the scope of the invention that further switching points are derived from the predetermined switching point and marked by switching markings, which switching points are upstream or downstream along the path movement. For example, a pre-switching point can be derived from the actual switching point, which lies on the painting line before the switching point. Furthermore, a post-switching point can be derived from the switching point marked by switching markings, which is on the painting line behind the switching point. Different switching actions can then be carried out at the pre-switching point, the switching point and the switching point.

For example, a coating agent valve can be opened at the upstream point, which releases the coating agent jet. At this point in time, a collecting device then remains active, which catches the emitted coating agent jet, so that the coating agent jet does not initially reach the component surface.

At the actual switching point, the collecting device is switched inactive, so that the coating agent jet strikes the component surface immediately after the switching time.

At a first post-switching point, the collecting device can then again be activated so that the coating agent jet no longer strikes the component surface immediately after the switching time.

The coating agent valve can then finally be closed at a second post-switching point, so that the coating agent jet is switched off.

The use of such a collecting device offers the possibility that the coating agent jet can be switched on or off relatively suddenly, with no transient transition processes occurring.

The above-mentioned collecting device is also described in detail in terms of construction and mode of operation in the applicant's parallel and simultaneously filed German patent application entitled "Coating device and corresponding operating method". The content of this parallel German patent application is therefore fully attributable to the present application with regard to the construction and operation of the collecting device.

It should also be mentioned that the term “switching action” used in the context of the invention is to be understood generally and is not restricted to the switching on or switching off of the coating agent jet. Rather, a fluid flow can generally be switched on or off, such as an air flow or a directed air flow from an atomizer. In addition, the switching action can consist of switching an electrostatic coating agent charge on or off. Furthermore, the switching action can consist in activating or deactivating a fall arrester or generally an actuator. In this context it should also be mentioned that the switching action does not necessarily consist in a qualitative switch between two states (ON / OFF). Rather, there is also the possibility within the scope of the invention that a switching action consists in a continuous change of an operating parameter.

It has already been mentioned above that the switching markings are optical switching markings which are generated by irradiating the component surface with light. In this connection it should be mentioned that the light for generating the switching markings can optionally be in the visible wavelength range, in the infrared wavelength range or in the ultraviolet wavelength range.

In one variant of the invention, the light from the light source is broadband with a wavelength spectrum with a bandwidth of at least 100 nm, 250 nm or 500 nm.

However, there is alternatively also the possibility that the light of the wavelength has a narrow-band wavelength spectrum with a bandwidth of at most 50 nm, 25 nm, 10 nm or at most 1 nm in order to reduce the susceptibility to interference from ambient light, the optical sensor then being in one narrow-band wavelength range is sensitive, which is within the wavelength spectrum of the light source.

Regarding the light source, it should also be mentioned that the light source can be arranged to be either stationary or spatially movable. In any case, however, it is provided that the light source can move the light beam spatially in order to generate the optical switching marking at the desired location on the component surface.

Regarding the switching marking on the component surface, it should be mentioned that the switching marking can be a light surface, a light strip or a light spot or can contain a light pattern.

For example, the switching marking can mark a border of a partial area to be coated on the component surface in a line shape, the partial area to be coated being surrounded in this case by a light strip. Alternatively, the switching marking can mark a partial surface to be coated on the component surface. There is also the possibility that the switching points are marked in a punctiform manner.

With regard to the coating agent, the invention is not limited to lacquer, but can also be realized with other coating agents, such as, for example, adhesive, sealant or insulating material, to name just a few examples.

Also with regard to the application device used, the invention is not restricted to a specific type of application device. For example, the application device can be an atomizer, such as a rotary atomizer. Alternatively, an application device can be used which applies a droplet jet of the coating agent jet or a coherent coating agent jet. Such application devices are from the patent applications already mentioned at the beginning DE 10 2013 002 412 A1 , DE 10 2013 002 413 A1 , DE 10 2013 002 433 A1 and DE 10 2013 002 411 A1 is known, so that the content of these patent applications of the present description with regard to the structure and functioning of the application device is fully attributable.

It should also be mentioned that the invention is not only suitable for coating motor vehicle body components or add-on parts for motor vehicles. Rather, other types of components can also be coated within the scope of the invention become.

Regarding the switching points, it should be mentioned that these preferably indicate a boundary between a paint-free area and an area to be painted.

It should also be mentioned that the optical sensor is preferably mechanically connected to the application device and is moved synchronously with the application device over the component surface.

In this case, the optical sensor preferably has a detection area which leads the movement of the application device. The optical sensor preferably looks ahead on the programmed painting path in order to be able to recognize a switching mark on the component surface in good time.

However, there is alternatively also the possibility that the optical sensor is arranged separately from the application device, for example in a stationary manner.

Finally, it should be mentioned that the invention also claims protection for a coating system according to the invention which carries out the coating method described above. The structure and the mode of operation of this coating system according to the invention already result from the above description, so that a separate description of the coating system can be dispensed with.

Figur 1

eine schematische Darstellung einer herkömmlichen Bahnlackierung, wobei der tatsächliche Schaltpunkt exakt mit dem programmierten Schaltpunkt übereinstimmt,

Figur 2

eine Abwandlung von Figur 1, wobei der tatsächliche Schaltpunkt auf der Bahn vor dem programmierten Schaltpunkt liegt,

Figur 3

eine Abwandlung von Figur 1, wobei der tatsächliche Schaltpunkt auf der Bahn hinter dem programmierten Schaltpunkt liegt,

Figur 4

eine schematische Darstellung einer erfindungsgemäßen Beschichtungsanlage, die Schaltmarkierungen auf der Bauteiloberfläche erkennt,

Figur 5

eine andere Darstellung der Beschichtungsanlage aus Figur 4 mit einer zusätzlichen Schaltpunktsteuerung und einer Robotersteuerung,

Figur 6

ein Steuerdiagramm zur Verdeutlichung der Arbeitsteilung zwischen der Robotersteuerung und der Schaltpunktsteuerung gemäß Figur 5,

Figur 7

eine Abwandlung von Figur 5,

Figur 8

eine schematische Darstellung zur Verdeutlichung der Erfindung,

Figur 9

ein Signaldiagramm des Ausgangssignals des Sensors zur Erkennung der Schaltmarkierungen,

Figur 10

ein Flussdiagramm zur Verdeutlichung der Erzeugung der Schaltmarkierungen auf der Bauteiloberfläche,

Figur 11

ein Flussdiagramm zur Verdeutlichung der Erkennung der Schaltmarkierungen auf der Bauteiloberfläche,

Figur 12A

eine schematische Darstellung einer Auffangvorrichtung zum Auffangen des Beschichtungsmittelstrahls im inaktiven Zustand,

Figur 12B

die Auffangvorrichtung aus Figur 12A im aktivierten Zustand, sowie

Figur 13

ein Diagramm zur Verdeutlichung eines Vorschaltpunktes, eines Schaltpunktes und zweier Nachschaltpunkte auf einer programmierten Roboterbahn.

Other advantageous developments of the invention are characterized in the subclaims or are explained in more detail below together with the description of the preferred exemplary embodiments of the invention with reference to the figures. Show it:

Figure 1

1 shows a schematic representation of a conventional web coating, the actual switching point exactly matching the programmed switching point,

Figure 2

a variation of Figure 1 , whereby the actual switching point lies on the path before the programmed switching point,

Figure 3

a variation of Figure 1 , with the actual switching point on the path behind the programmed switching point,

Figure 4

1 shows a schematic representation of a coating system according to the invention, which recognizes switching markings on the component surface,

Figure 5

another representation of the coating system Figure 4 with an additional switching point control and a robot control,

Figure 6

a control diagram to illustrate the division of labor between the robot controller and the switching point control according to Figure 5 ,

Figure 7

a variation of Figure 5 ,

Figure 8

1 shows a schematic illustration to illustrate the invention,

Figure 9

a signal diagram of the output signal of the sensor for recognizing the switching markings,

Figure 10

1 shows a flowchart to illustrate the generation of the switching markings on the component surface,

Figure 11

1 shows a flow chart to clarify the detection of the switching markings on the component surface,

Figure 12A

1 shows a schematic representation of a collecting device for collecting the coating agent jet in the inactive state,

Figure 12B

the fall arrester Figure 12A in the activated state, as well

Figure 13

a diagram to illustrate a pre-switching point, a switching point and two post-switching points on a programmed robot path.

The Figures 1 to 3 initially show various illustrations to illustrate a web-oriented painting. An application device is guided along a painting path 1 over a component surface, the application device first passing a predetermined (programmed) paint-free area 2 and then reaching a predetermined (programmed) painting area 3 that is to be painted. The painting area 3 is separated from the paint-free area 2 by a boundary 4. At the boundary 4 between the paint-free area and the painting area 3 there is a programmed switch-on point 4.2 at which the application device is to be switched on, so that the application device then subsequently paints the painting area 3 on the painting web 1.

It should be noted here that in practice the actual switch-on point 5 deviates from the programmed switch-on point 4.2, which leads to coating errors, as will be explained below.

In the illustration according to Figure 1 The actual switch-on point 5 coincides with the programmed switch-on point 4.2 and lies exactly on the limit 4, so that there is no deviation between the programmed desired switch-on point 4.2 and the actual switch-on point 5.

In the illustration according to Figure 2 on the other hand, the actual switch-on point 5 lies on the painting line 1 in front of the boundary 4 between the programmed paint-free area 2 and the programmed painting area 3. This results in an undesirable coating of the paint-free area 2 between the switch-on point 5 and the border 4 in an area 3.2 , which should actually be paint-free.

Figure 3 on the other hand shows a modification in which the actual switch-on point 5 on the painting line 1 lies behind the boundary 4 between the programmed paint-free area 2 and the programmed painting area 3. As a result, an undercoating occurs in the programmed painting area 3 on the painting line 1 between the boundary 4 and the switch-on point 5 in an area 3.3.

The Figures 2 and 3 thus show various undesirable deviations of the actual switch-on point 5 from the programmed switch-on point 4.2. These undesirable deviations are prevented or at least reduced by the invention.

Therefore, reference is now made to the exemplary embodiment according to FIGS Figures 4 to 6 . The drawings thus show a component 6 to be coated (for example a motor vehicle body component) which has a component surface 7 to which an application device 8 applies a coating agent jet 9, which is known per se from the prior art and therefore need not be described in more detail .

The application device 8 is guided by a multi-axis coating robot 10 with serial robot kinematics along the painting path 1 over the component surface 7, which is also known per se from the prior art.

Furthermore, the drawings show a laser 11, which directs a laser beam 12 onto the component surface 7 and thereby generates an optically visible switching marking 13 on the component surface 7. The laser beam 12 can be deflected by a suitable deflection device in such a way that the switching marking 13 is generated at the desired position on the component surface 7. The switching markings 13 are positioned as a function of predefined CAD data of the component 6 and as a function of the measured position of the component 6.

Furthermore, the drawings show that an optical sensor 14 is attached to the application device 8, the optical sensor 14 being guided together with the application device 8 by the coating robot 10 over the component surface 7.

The optical sensor 14 (eg camera) has a detection area 15 which leads the coating agent jet 9 along the painting path 1. The optical sensor 14 can thus recognize in advance when moving along the painting line whether one of the switching markings 13 is recognizable on the component surface 7. This foresight of the optical sensor 14 allows sufficient time for the coating agent jet 9 to be switched on or off so that the coating agent jet 9 is switched on or off as precisely as possible when it passes the switching marking 13.

Out Figure 5 it can also be seen that the coating robot 10 is controlled by a conventional robot controller 16.

In addition, a separate switching point control 17 is provided, which is connected on the input side to the optical sensor 14 via a signal path 18 in order to detect one of the switching markings 13 on the component surface 7. On the output side, on the other hand, the switching point controller 17 is connected via a signal path 19 to a coating agent valve 20 in the application device 8 in order to be able to switch the coating agent jet 9 on or off.

In addition, the robot controller 16 is connected to the switching point controller 17 via a signal path 21, so that the robot controller 16 can transfer control of the switching signal assignment to the switching point controller 17, as in FIG Figure 6 is shown and described below.

In an operating phase 22, only the robot controller 16 controls the coating robot 10.

In a subsequent operating phase 23, the robot controller 16 then transfers control to the switching point controller 17, since the robot controller 16 approaches a programmed one Detects switching point.

In an operating phase 24, the switching point controller 17 checks by querying the optical sensor 14 whether one of the switching markings 13 is recognized.

In the operating phase 25, one of the switching markings is then recognized by the switching point control 17. Thereupon, the switching point controller 17 begins to control an operation. The term “process” is to be understood generally here and can consist, for example, in the actuation of the coating agent valve 20. In general, however, the "process" can also be the control of an air flow, a paint flow or the switching (switching on or switching off) of electricity or light, to name just a few examples.

During an operating phase 27, the coating agent valve 20 in the application device 8 opens, whereby the coating agent jet 9 is released.

At the same time, the robot controller 16 continues to control the coating robot 10 during an operating phase 28.

The division of tasks described above between the robot controller 16 on the one hand and the switching point controller 17 on the other hand is advantageous, as will be explained in the following. For example, the robot controller 16 usually controls the coating robot 10 with a specific control cycle of, for example, 4 ms. During this control cycle, at a travel speed of, for example, 1000 mm / s, there is a certain travel path of, for example, 4 mm, so that the robot controller 16 could only position the switching point 13 with a corresponding positional inaccuracy.

The switching point control 17, on the other hand, can work much faster and therefore also react much faster to the switching markings 13.

Figure 7 shows a modification of the embodiment according to the Figures 4 to 6 , so that to avoid repetition reference is made to the above description, the same reference numerals being used for corresponding details.

A special feature of this exemplary embodiment is that the switching point controller 17 is integrated in the robot controller 16.

Figure 8 shows various positions A, B and C of the application device 8 along a programmed painting path, wherein the position A is shown with a solid line, while the position B is indicated with a dashed line, whereas the position C is represented by a dotted line.

In position A, the optical sensor 14 cannot yet recognize the switching marking 13 of the component surface 7. In position B, on the other hand, the switching marking 13 lies on the component surface 7 within the detection area 15 of the optical sensor 14, so that a switching action (for example switching on or switching off the coating agent jet 19) is triggered.

Figure 9 shows the associated output signal of the optical sensor 14, a peak 29 being recognizable at position B, which indicates the detection of the switching marking 13.

Figure 10 shows a flowchart to illustrate the generation of the switching markings 13 on the component surface 7 of the component 6 to be coated.

In a first step S1, the position of the component 6 along the painting line is first detected. This can be done, for example, by reading out a belt encoder of the conveyor of the painting line, which is known per se from the prior art.

The position of the desired switching points on the component 6 is then calculated in a step S2. On the one hand, CAD data of the component 6 are taken into account, which reflect the spatial shape of the component 6. On the other hand, the measured position of the component 6 along the painting lines is also taken into account. Finally, the programmed relative position of the predetermined switching points on the component 6 is also taken into account, i. H. recorded in a component-related coordinate system.

In a further step S3, the switching markings 13 are generated on the component surface 7 by the laser 11 directing the laser beam 12 onto the component surface 7.

Figure 11 shows a flowchart to illustrate the mode of operation of the switching point control 17 when the switching markings are recognized.

In a step S1, the application device 8 is moved by the coating robot 10 along a painting path over the component surface 7.

In step S2, it is continuously checked whether the switching mark 13 is visible on the upcoming painting line which indicates a switching point.

If such a switching marking 13 is recognized, then a step S3 proceeds to a step S4, in which the desired switching action is then carried out, such as switching the coating agent jet 9 on or off.

The Figures 12A and 12B show a collecting device 30 according to the invention for collecting the coating agent jet 9.

The collecting device 30 essentially consists of a linearly movable cutting edge 31, which can be linearly moved by an actuator 32 in the direction of the double arrow in order to selectively collect the coating agent jet 9 (cf. Figure 12B ) or to release (cf. Figure 12A ). The actuator 32 can be controlled by switching points on the component surface 7, as will be described in detail.

In addition, the drawings also show a suction line 33 and a fluid supply line 34. The suction line 33 serves to suction off the collected coating agent in the active state of the collecting device 30 according to FIG Figure 12B . The fluid supply line 34, on the other hand, serves to supply a rinsing agent so that the coating agent does not clump in the collecting device 30.

Figure 13 shows the movement of an application device along a painting line 35, several points P1, P2, P3 and P4 being passed in succession.

The point P2 is the actual switching point, which is indicated by a switching mark 13 on the component surface becomes. At the switching point P2, the collecting device 30 is switched to inactive, as in FIG Figure 12A is shown, so that the coating agent jet 9 can strike the component surface 7.

The coating agent valve 20 had already been opened at point P1.

In the following step P3, the collecting device 30 is then activated, as in FIG Figure 12B is shown, so that the coating agent jet 9 no longer strikes the component surface.

Finally, the coating agent valve 20 is closed at the point P4, so that a coating agent jet 9 is no longer emitted.

It was already briefly mentioned above that the point P2 is the actual switching point, which is indicated by the switching marker 13.

In contrast, the point P1 is a pre-switching point that is derived from the switching point P2.

Points P3 and P4 are also derived from the actual switching point P2 and lie on the painting line 35 behind the actual switching point P2.

The invention is not restricted to the preferred exemplary embodiments described above. Rather, a large number of variants and modifications are possible which fall within the scope of protection defined by the appended claims.

Reference symbol list:

1

Painting line

2nd

Paint-free area

3rd

Painting area

3.2

Area of the paint-free area that is coated due to errors

3.3

Area of the painting area that is not coated due to errors

4th

Border between paint-free area and paint area

4.2

Programmed switch-on point

5

Actual switch-on point

6

Component

7

Component surface

8th

Application device

9

Coating agent jet

10th

Coating robot

11

laser

12th

laser beam

13

Shift mark

14

Optical sensor

15

Detection area of the optical sensor

16

Robot control

17th

Switch point control

18th

Signal path from the sensor to the switching point control

19th

Signal path from the switching point control to the coating agent valve

20th

Coating agent valve

21

Signal path from the robot controller to the switching point controller

22-28

Operating phases

29

Peak of the sensor signal at the switching mark

30th

Fall arrester

31

Cutting edge to catch the coating agent jet

32

Actuator for moving the cutting edge

33

Suction line

34

Fluid supply line

35

Painting line

P1-P4

Switching points

Claims (15)

1. Coating method for coating a component (6) with a coating agent, in particular for painting motor vehicle body components or an aviation industry component in a painting installation, comprising the following steps:

   a) moving an application device (8) over a component surface (7) of the component (6) that is to be coated, in particular by means of a multi-axis coating robot (10), in particular along a programmed painting path (1; 35),

   b) defining specific switching points on the component surface (7) to be coated for initiating a switching action, in particular for switching on or switching off a coating agent jet (9) at the switching points, wherein the switching points are marked on the component surface (7) by generating an optical switching marking (13) on the component surface (7) at the individual switching points,

   c) detecting the switching markings (13) corresponding to the individual switching points during movement of the application device (8) by an optical sensor (14),

   d) performing the switching action when one of the switching points is reached each at the detection of the individual switching markings (13) on the component surface (7),
   characterised

   e) in that the optical switching markings (13) on the component surface (7) are generated by means of a light source (11), in particular by means of a laser (11) or a laser diode.
2. Coating method according to claim 1, characterised in that

   a) the application device (8) is moved over the component surface (7) by a multi-axis coating robot (10), the coating robot preferably being an articulated robot or a linear machine,

   b) in that the movement of the coating robot (10) is controlled by a robot control (16), and

   c) in that the generation of the switching markings (13), the detection of the switching markings (13) and/or the switching on and switching off of the application device (8) is controlled by a switching point control (17) .
3. Coating method according to claim 2,
   characterised in that

   a) the switching point control (17) is integrated into the robot control (16), and/or

   b) in that the switching point control (17) on the one hand and the robot control (16) on the other hand are in the form of separate software modules in a common control unit, or

   c) in that the switching point control (17) on the one hand and the robot control (16) on the other hand are in the form of separate hardware modules in a common control unit.
4. Coating method according to claim 2,
   characterised in that

   a) the switching point control (17) is separate from the robot control (16),

   b) in that the switching point control (17) on the one hand and the robot control (16) on the other hand are in the form of separate hardware modules, and/or

   c) in that the switching point control (17) has a quicker response behaviour than the robot control (16) in order to permit as quick a reaction as possible to the switching points.
5. Coating method according to any one of the preceding claims, characterised by the following steps:

   a) providing CAD data of the component (6) to be coated, the CAD data describing the spatial form of the component (6),

   b) detecting the spatial position of the component (6) to be coated, in particular along a painting line, and

   c) defining the spatial position of the switching markings (13) in dependence on the detected spatial position of the component (6) to be coated and in dependence on the CAD data of the component (6) to be coated.
6. Coating method according to any one of the preceding claims, characterised by the following steps when a switching marking (13) is detected on the component surface (7):

   a) defining an upstream switching point (P1) which is situated on the painting path (1; 35) before the switching point (P2) associated with the detected switching marking (13),

   b) defining a downstream switching point (P3, P4) which is situated on the painting path (1; 35) after the switching point (P2) associated with the detected switching marking (13),

   c) performing different switching actions at the upstream switching point (P1), the switching point (P2) and the downstream switching point (P3, P4).
7. Coating method according to claim 6,
   characterised by

   a) the following switching actions at the upstream switching point (P1) :

   a1) opening a coating agent valve in order to switch on the coating agent jet (9), and

   a2) moving an intercepting device (30) into an active intercepting position in which the intercepting device (30) collects the coating agent jet (9) so that the coating agent jet (9) does not reach the component surface (7),

   b) the following switching actions at the switching point (P2) :

   b1) holding the coating agent valve open,

   b2) moving the intercepting device (30) into an inactive position in which the intercepting device (30) does not collect the coating agent jet (9) so that the coating agent jet (9) reaches the component surface (7),

   c) the following switching actions at the downstream switching point (P3, P4):

   c1) closing the coating agent valve, and/or

   c2) moving the intercepting device (30) into the intercepting position in which the intercepting device (30) collects the coating agent jet (9) so that the coating agent jet (9) does not reach the component surface (7).
8. Coating method according to any one of the preceding claims, characterised in that at least one of the following switching actions is performed at each of the switching points:

   a) switching on or switching off a fluid stream, in particular the coating agent jet (9) or an air jet, in particular a guiding air jet for shaping the coating agent jet (9),

   b) switching on or switching off an electrostatic coating agent charge,

   c) activating or deactivating an intercepting device (30) which in the activated state intercepts the coating agent jet (9) before it strikes the component surface (7) .
9. Coating method according to any one of the preceding claims, characterised in that

   a) the optical switching markings (13) are generated by irradiating the component surface (7) with light

   a1) in the visible wavelength range or

   a2) in the infra-red wavelength range or

   a3) in the ultraviolet wavelength range, and/or

   b) in that the light source (11) emits light

   b1) which is wide-band with a wavelength spectrum having a bandwidth of at least 100 nm, 250 nm or 500 nm or

   b2) which has a narrow-band wavelength spectrum having a bandwidth of not more than 50 nm, 25 nm, 10 nm or 1 nm, in order to reduce the susceptibility to faults in respect of ambient light, the optical sensor (14) being sensitive in a narrow-band wavelength range which lies within the wavelength spectrum of the light source (11), and/or

   c) in that the light source (11) for generating the optical switching markings (13)

   c1) is stationary or

   c2) is arranged to be spatially movable, and/or

   d) in that the switching marking (13) on the component surface (7)

   d1) is an area of light or

   d2) is a strip of light or

   d3) is a point of light or

   d4) contains a light pattern, and/or

   e) in that the switching marking (13)

   e1) marks in a linear manner an outline of a sub-area on the component surface (7) that is to be coated or

   e2) marks the entirety of a sub-area on the component surface (7) that is to be coated or

   e3) marks one of the switching points in a point-like manner,
   and/or

   f) in that the coating agent is

   f1) a paint,

   f2) an adhesive,

   f3) a sealant or

   f4) an insulating material, and/or

   g) in that the application device (8)

   g1) is an atomiser, in particular a rotary atomiser or

   g2) applies a jet of droplets of the coating agent or

   g3) applies the coating agent jet (9) as a cohesive coating agent jet (9), and/or

   h) in that the component (6) to be coated is

   h1) a motor vehicle body component,

   h2) an attached part for a motor vehicle or

   h3) an aviation component, and/or

   i) in that the switching points each indicate a boundary (4) between a paint-free region (2) and a region (3) that is to be painted, and/or

   j) in that the optical sensor (14)

   j1) is connected mechanically to the application device (8) and is moved over the component surface (7) synchronously with the application device (8) or

   j2) is separated mechanically from the application device (8), and/or

   k) in that the optical sensor (14) has a detection region (15) which moves ahead of the movement of the application device (8).
10. Coating installation for coating a component (6) with a coating agent, in particular for carrying out the coating method according to any one of the preceding claims, with

    a) a marking device (11) for generating optical switching markings (13) on the component surface (7) of the component (6) to be coated, the switching markings (13) indicating switching points at which the coating installation is to perform a switching action, and

    b) an optical sensor (14) for detecting the switching markings (13) on the component surface (7),
    characterised in that

    c) the marking device (11) has a light source (11), in particular a laser (11) or a laser diode, wherein the light source (11) generates the optical switching markings (13) on the component surface (7).
11. Coating installation according to claim 10,
    characterised by

    a) a switching point control (17) for controlling the switching actions,

    b) the switching point control (17) being connected on the input side to the sensor (14) in order to detect the switching marking (13),

    c) while the switching point control (17) is connected on the output side to an actuator, in particular to a coating agent valve, in order to initiate the switching action when the sensor (14) detects one of the switching markings (13) on the component surface (7).
12. Coating installation according to claim 11,
    characterised by

    a) an application device (8) for delivering a coating agent jet (9) to the component surface (7),

    b) a multi-axis coating robot (10) which guides the application device (8) over the component surface (7), the coating robot preferably being an articulated robot or a linear machine, and

    c) a robot control (16) which controls the coating robot (10) so that the application device (8) performs a programmed movement over the component surface (7).
13. Coating installation according to claim 12,
    characterised in that

    a) the switching point control (17) is integrated into the robot control (16), and/or

    b) in that the switching point control (17) on the one hand and the robot control (16) on the other hand are in the form of separate software modules in a common control unit, or

    c) in that the switching point control (17) on the one hand and the robot control (16) on the other hand are in the form of separate hardware modules in a common control unit.
14. Coating installation according to claim 12,
    characterised in that

    a) the switching point control (17) is separate from the robot control (16),

    b) in that the switching point control (17) on the one hand and the robot control (16) on the other hand are in the form of separate hardware modules, and/or

    c) in that the switching point control (17) has a quicker response behaviour than the robot control (16) in order to permit as quick a reaction as possible to the switching points.
15. Coating installation according to any one of claims 10 to 13,
    characterised in that

    a) for intercepting the coating agent jet (9), an intercepting device (30) is provided,

    b) in that the intercepting device (30) is movable between an active intercepting position and an inactive position,

    c) in that the intercepting device (30) in the intercepting position collects the coating agent jet (9) and thereby prevents the coating agent jet (9) from reaching the component surface (7), and

    d) in that the intercepting device (30) in the inactive position does not collect the coating agent jet (9) so that the coating agent jet (9) reaches the component surface (7).

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