EP3227030B1 - Coating method and corresponding coating installation - Google Patents

Description

The invention relates to a coating method for coating components, in particular for coating motor vehicle body components in a paint shop. Furthermore, the invention relates to a corresponding coating system.

In the coating of motor vehicle body components are usually used as application device rotary atomizers, which deliver a rotationally symmetrical coating agent jet and accordingly generate a rotationally symmetrical spray pattern on the component surface. The angular orientation of such a rotary atomizer with respect to the longitudinal axis of the coating agent jet in this case generally plays no role, since the coating agent jet is rotationally symmetrical. Exceptionally, however, the angular position of the rotary atomizer can play a role if the coating agent jet is blown unbalanced by shaping air, which then leads to a correspondingly asymmetrical spray pattern on the component surface. So far, however, the attempt has not been made to influence the angular position of the rotary atomizer during operation targeted.

From the prior art (eg DE 10 2013 002 412 A1 However, other application devices are known which apply a coating agent beam which is not rotationally symmetrical and therefore generates on the component surface and a spray pattern that is not rotationally symmetrical.

This can be problematic if such application devices are used to coat a component surface by applying a plurality of adjacent coating webs 1 on the component surface, as in FIG. 7 is shown. In this case, the coating webs 1 must adjoin one another as directly as possible without gaps and without overlaps, since the application device emits a rectangular, sharp-edged spray pattern 2. The coating webs 1 therefore have a path 3 which runs parallel between the adjacent coating webs 1, so that the adjacent coating webs 1 adjoin one another without overlapping and without gaps. However, this leads to problems if the component to be coated is delimited by two component edges 4, 5 which do not run parallel to one another. So shows FIG. 7 a straight component edge 4 and a curved component edge 5, wherein the coating webs 1 conform to the curved component edge 5, which leads to uncoated regions 6 in the region of the other component edge 4. It should be noted that the application device is not rotated during the movement along the path 3, so that the spray pattern 2 is always aligned with its longitudinal direction 7 at right angles to the path 3 and thus parallel to the web transverse direction. This alignment of the spray pattern 2 leads to a maximum web width of the coating web 7.

The problem of the uncoated areas 6 according to FIG. 7 can be solved in that the individual coating webs 1 are not exactly parallel to each other, as in FIG. 8 is shown, in FIG. 8 corresponding details are provided with the same reference numerals as in FIG. 7 , In this case, the lower coating webs 1 are curved and nestle against the lower component edge 5.

At the top, the coating webs 1 then become more and more straight-line and then nestle increasingly against the upper component edge 4. In this way, the uncoated regions 6 are avoided. However, this leads to overlaps between adjacent coating webs 1 and thereby overcoated areas 8 with a correspondingly excessive layer thickness, which is also undesirable. Again, the application device is not rotated during movement along the path 3, so that the spray pattern 2 is always aligned with its longitudinal direction 7 at right angles to the path 3 and thus parallel to the web transverse direction.
The general technical background is further on DE 10 2011 114 382 A1 to point. This document discloses a coating method in which the spray is tilted during painting relative to the component surface to compensate for asymmetries. However, this is not useful in painting webs that are not exactly rectangular.
The general technical background of the invention is also to be noted JP 3 313 949 B2 ,
Finally revealed DE 10 2010 004 496 A1 a coating method according to the preamble of claim 1 or a coating system according to the preamble of claim 10. However, this prior art does not allow coating of motor vehicle body components with overlapping coating center lines.
The invention is therefore based on the object of preventing the uncoated regions 6 and the overcoated region 8 on the component surface when an application device is used, which applies a coating agent beam, which is not rotationally symmetrical and thus generates an elongated spray pattern with a certain longitudinal direction on the component surface.

This object is achieved by a coating method according to the invention and by a corresponding coating system according to the dependent claims.

The invention initially provides, in accordance with the prior art, for an application device to be coated over one Component surface is guided along a predetermined coating path. During this movement, the application device dispenses a coating agent jet onto the component surface, wherein the coating agent beam is not rotationally symmetrical with respect to its beam axis and therefore generates an elongated spray pattern with a specific longitudinal direction on the component surface. For example, the spray pattern may be approximately rectangular. In such an elongated spray pattern, the angular position of the application device relative to the trajectory is not insignificant, as is the case with rotary atomizers.

The invention therefore provides that the application device is rotated about the beam axis during the movement over the component surface, so that the angular position of the longitudinal direction of the spray pattern changes relative to the web transverse direction or relative to the web path along the coating web. In this way, the width of the applied coating web along the coating web can be changed.

To achieve a maximum web width, the application device is rotated so that the longitudinal direction of the spray pattern is aligned at right angles to the path, since the spray pattern then sweeps over the component surface with its maximum width.

In order to achieve a minimum web width of the applied coating web, however, the application device is rotated so that the longitudinal direction of the elongated spray pattern runs parallel to the path, since the elongated spray pattern then sweeps over the component surface with its smaller width.

The rotation of the application device during the movement of the application device along the coating path thus makes it possible to continuously adapt the width of the coating path between a maximum value and a minimum value. The maximum value of the web width of the coating web is determined by the longitudinal extent of the spray pattern along the longitudinal direction of the spray pattern. By contrast, the minimum value of the web width of the coating web is determined by the transverse extent of the elongated spray pattern transversely to its longitudinal direction. Within these limits, which are determined by the maximum value and the minimum value, the web width can be adjusted continuously by a suitable rotation of the application device.

The term used in the context of the invention for a rotation of the application device is preferably based on the entire application device, which is rotated. To distinguish this is for example the rotation of the bell cup in a conventional rotary atomizer. The decisive factor is that the rotation of the application device also leads to a corresponding rotation of the spray pattern on the component surface.

It should be noted that the angle of rotation of the application device with respect to the trajectory also has an influence on the layer thickness. If the application device is rotated so that the maximum web width is reached, this leads to a minimum layer thickness, if the other coating parameters remain unchanged. On the other hand, if the application device is rotated so that the web width is minimal, this leads to a maximum layer thickness, if the other coating parameters remain unaffected. The twist angle of the application device thus has an influence on the resulting layer thickness, which is undesirable in itself, since the layer thickness should be as constant as possible.

In the context of the invention, therefore, this disturbing influence of the angle of rotation on the layer thickness is preferably compensated in order to achieve a constant layer thickness. Depending on the permissible layer thickness tolerance, however, it is not always absolutely necessary to compensate for the layer thickness deviations by the rotation of the applicator.

One way to compensate for this disturbing effect of the angle of rotation on the layer thickness is to change the travel speed of the application device along the coating path accordingly. If the application device is rotated in such a way that a maximum web width of the coating web and a correspondingly minimum layer thickness are achieved, the undesired decrease in the coating thickness is compensated by a slowing of the travel speed. In contrast, if the application device is rotated in such a way that a minimum web width and a corresponding maximum layer thickness are achieved, the undesired increase in the layer thickness is compensated by a corresponding increase in the travel speed.

Another possibility of compensating the disturbing influence of the rotation of the application device on the layer thickness is to adjust the coating medium flow accordingly. If the application device is rotated in such a way that the web width is maximum and the layer thickness correspondingly minimal, the undesirable decrease in the layer thickness can be compensated for by a corresponding increase in the coating medium flow (mass flow or volume flow). If the application device is rotated in this way, that the web width is minimal and the layer thickness corresponding to a maximum, so the undesirable increase in the layer thickness can be compensated by the fact that the coating medium flow is reduced.

mit:

α :

Verdrehwinkel zwischen der Längsrichtung des Spritzbildes und der Bahnquerrichtung,

V0 :

Verfahrgeschwindigkeit des Applikationsgerätes, wenn der Verdrehwinkel α zwischen der Längsrichtung des Spritzbildes und der Bahnquerrichtung Null ist,

V(α) :

Angepasste Verfahrgeschwindigkeit bei dem aktuellen Verdrehwinkel α zur Erreichung einer möglichst konstanten Schichtdicke.

The above-described adjustment of the travel speed of the application device as a function of the angle of rotation of the application device can be carried out according to the following formula in the context of the invention: $$\mathrm{V}\left(\mathrm{\alpha }\right)=\mathrm{V}0/\cos \left(\mathrm{\alpha }\right).$$

With:

α:

Twist angle between the longitudinal direction of the spray pattern and the web transverse direction,

V0:

Traversing speed of the application device when the angle of rotation α between the longitudinal direction of the spray pattern and the web transverse direction is zero,

V (α):

Adapted traversing speed at the current angle of rotation α to achieve the most constant possible layer thickness.

For painting large component surfaces (for example the roof of a motor vehicle body), the invention provides for several adjacent coating webs to be applied to the component surface, with the adjacent component surfaces being adjacent to each other as completely as possible and without overlapping in order to avoid overcoated areas and undercoated areas.

This is relatively easy in the coating of rectangular component surfaces, since then simply parallel coating webs can be applied.

However, the invention is also suitable for the coating of component surfaces, which are not exactly rectangular as a whole, as is usually the case with motor vehicle body components. The invention then provides that the applied coating webs are also not exactly rectangular, in order to adapt to the non-rectangular component surface. This can be achieved within the scope of the invention by the application device being continuously rotated during the travel of the individual coating webs in order in each case to achieve the desired web width. When the individual coating webs are moved off, the application device is thus rotated in each case so that no overlaps with adjacent coating webs or gaps between the adjacent coating webs occur.

In a preferred embodiment of the invention, the application device is moved by a multi-axis application robot over the component surface. Such application robot are known from the prior art and therefore need not be described in detail. It should be mentioned at this point merely that the application robot is preferably a multi-axis robot with, for example, six or seven axes and a serial kinematics, wherein the application robot can be optionally mounted stationary or displaceable.

The application robot and the application device are controlled in operation by a robot controller according to a parameter set, the parameter set can specify, for example, the speed of the application device, the acceleration of the application device, the angle of rotation of the application device, the rotational speed of the application device, the applied coating agent flow or the coating distance.

In the context of the invention, there is the possibility that this parameter set is changed during the movement along the coating path, ie. H. within a coating path.

This change of the parameter set can be done, for example, continuously. However, there is also the alternative possibility that the coating web is subdivided into a plurality of successive web sections, which are traversed one after the other, wherein the parameter set for controlling the application device and the application robot is kept constant within the individual web sections and changes from one web section to the next.

mit:

SB1:

Breite des Spritzbildes entlang der Längsrichtung des Spritzbildes,

SB2:

Gewünschte Bahnbreite der Beschichtungsbahn,

α:

Verdrehwinkel zwischen der Längsrichtung des Spritzbildes und der Bahnquerrichtung.

It has already been mentioned above that the web width of the applied coating web can be changed by rotating the application device accordingly. The angle of rotation of the application device is therefore preferably calculated within the scope of the invention as a function of the desired web width and the maximum width of the spray pattern along its longitudinal direction. For example, this calculation can be made according to the following formula: $$\mathrm{\alpha \; =\; <figure-callout\; id="2"\; label="arccos\; SB"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">arccos\; </figure-callout>}\left(\mathrm{SB}\right)\left(2/\mathrm{<figure-callout\; id="1"\; label="SB"\; filenames="imgf0002.png"\; state="\{\{state\}\}">SB</figure-callout>}1\right).$$

With:

SB1:

Width of the spray pattern along the longitudinal direction of the spray pattern,

SB2:

Desired web width of the coating web,

α:

Angle of rotation between the longitudinal direction of the spray pattern and the web transverse direction.

It has already been mentioned above that the parameter set for controlling the application robot and the application device can be changed from one track section to the other track section. Preferably, this change takes place in a transition section.

mit:

α3 :

Verdrehwinkel am Ende des Übergangsabschnittes,

SB1:

Bahnbreite am Anfang des Übergangsabschnittes,

SB3:

Bahnbreite am Ende des Übergangsabschnittes.

The twist angle of the application device at the end of the transition section is preferably calculated according to the following formula: $$\mathrm{<figure-callout\; id="3"\; label="\alpha "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\alpha </figure-callout>}3\mathrm{=\; <figure-callout\; id="3"\; label="arccos\; SB"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">arccos\; </figure-callout>}\left(\mathrm{SB}\right)\left(3/\mathrm{<figure-callout\; id="1"\; label="SB"\; filenames="imgf0002.png"\; state="\{\{state\}\}">SB</figure-callout>}1\right).$$

With:

α3:

Twist angle at the end of the transition section,

SB1:

Web width at the beginning of the transition section,

SB3:

Web width at the end of the transition section.

mit:

V3 :

Verfahrgeschwindigkeit des Applikationsgerätes am Ende des Übergangsabschnittes,

V1 :

Verfahrgeschwindigkeit des Applikationsgerätes am Anfang des Übergangsabschnittes,

α3 :

Verdrehwinkel des Applikationsgerätes am Ende des Übergangsabschnittes.

By contrast, the travel speed of the application device at the end of the transitional section is preferably calculated according to the following formula: $$\mathrm{<figure-callout\; id="3"\; label="V"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}3=\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}1/\mathrm{<figure-callout\; id="3"\; label="cos\; \alpha "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">cos\; </figure-callout>}\left(\mathrm{\alpha }\right)\left(\mathrm{}3\right).$$

With:

V3:

Traversing speed of the application device at the end of the transitional section,

V1:

Traversing speed of the application device at the beginning of the transition section,

α3:

Angle of rotation of the application device at the end of the transitional section.

mit:

a2:

Beschleunigung des Applikationsgerätes während des Übergangsabschnittes,

V3:

Verfahrgeschwindigkeit des Applikationsgerätes am Ende des Übergangsabschnittes,

V1:

Verfahrgeschwindigkeit des Applikationsgerätes am Anfang des Übergangsabschnittes,

S2:

Länge des Übergangsabschnittes.

Along the transition section, the application device then experiences an acceleration, which is preferably calculated according to the following formula: $$\mathrm{a}2={\left(\mathrm{V}3-\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}1\right)}^2/\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">S</figure-callout>}\mathrm{2,}$$

With:

a2:

Acceleration of the application device during the transition section,

V3:

Traversing speed of the application device at the end of the transitional section,

V1:

Traversing speed of the application device at the beginning of the transition section,

S2:

Length of the transition section.

mit:

S2:

Länge des Übergangsabschnittes,

α3:

Verdrehwinkel des Applikationsgerätes am Ende des Übergangsabschnittes,

V3:

Verfahrgeschwindigkeit des Applikationsgerätes am Ende des Übergangsabschnittes,

V1:

Verfahrgeschwindigkeit des Applikationsgerätes am Anfang des Übergangsabschnittes,

ω2 :

Verdrehgeschwindigkeit des Applikationsgerätes auf dem Übergangsabschnitt.

The section length S2 of the transition section is then preferably calculated according to the following formula: $$\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">S</figure-callout>}2=\left[\mathrm{<figure-callout\; id="3"\; label="\alpha "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\alpha </figure-callout>}3\cdot \left(\mathrm{V}3-\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}1\right)\right]/\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\omega </figure-callout>}\mathrm{2,}$$

With:

S2:

Length of the transition section,

α3:

Twist angle of the application device at the end of the transition section,

V3:

Traversing speed of the application device at the end of the transitional section,

V1:

Traversing speed of the application device at the beginning of the transition section,

ω2:

Rotation speed of the application device on the transition section.

mit:

ω2 :

Verdrehgeschwindigkeit des Applikationsgerätes auf dem Übergangsabschnitt,

V1 :

Verfahrgeschwindigkeit des Applikationsgerätes am Anfang des Übergangsabschnittes,

SB1 :

Bahnbreite am Anfang des Übergangsabschnittes,

ΔSD% :

Schichtdickentoleranz.

The rotational speed of the application device on the transition section is then preferably calculated according to the following formula: $$\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\omega </figure-callout>}2=\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}1/\mathrm{<figure-callout\; id="1"\; label="SB"\; filenames="imgf0002.png"\; state="\{\{state\}\}">SB</figure-callout>}1\cdot \mathrm{\Delta SD\%}\cdot \mathrm{360\; °\; /\; \pi }.$$

With:

ω2:

Rotational speed of the application device on the transition section,

V1:

Traversing speed of the application device at the beginning of the transition section,

SB1:

Web width at the beginning of the transition section,

ΔSD%:

Layer thickness tolerance.

It should also be mentioned that the spray pattern is preferably sharp-edged, whereby the application device differs, for example, from rotary atomizers.

In addition, the spray pattern may be substantially rectangular. In the context of the invention, however, other forms of spray patterns are possible, such as elliptical spray patterns.

It should be mentioned with regard to the coating webs that they can be curved in order to conform to an odd component edge. In addition, the coating paths may be, for example, convex or concave. The side edges of the coating webs therefore do not have to run parallel to one another in the coating method according to the invention since the web width can be influenced by a corresponding rotation of the application device.

In addition, it should be mentioned that the application device is preferably guided over the component surface in such a way that the coating agent jet is aligned at the point of impact of the coating agent jet substantially at right angles to the component surface.

Finally, it should be mentioned that the invention also includes a corresponding coating system, as already apparent from the above description, so that a separate description of the coating system can be dispensed with at this point.

In this case, a robot controller rotates the application device during the movement along the coating path about the beam axis, so that the angle of rotation between the longitudinal direction of the spray pattern and the coating web changes along the coating path.

The term of a robot control used in the context of the invention is to be understood in this case generally and may include, inter alia, all hardware and software components that serve to control the application device and the application robot.

The robot controller can be centrally concentrated in a single assembly. However, it is alternatively also possible to distribute the various functions of the robot controller to a plurality of modules that communicate with each other.

The entire activation processes of the robot controller are preferably automatically provided by a higher-level software tool. By entering the component geometry to be coated and certain parameters (eg minimum or maximum permissible travel speed, layer thickness tolerance to be maintained, maximum permissible angle of rotation of the applicator, etc.), the software tool independently calculates the optimal path profile with corresponding angles of rotation and the appropriate orientation of the application device.

Figur 1

eine Aufsicht auf ein Dach einer Kraftfahrzeugkarosserie, wobei das Dach lackiert werden soll,

Figur 2

eine schematische Darstellung benachbarter Lackierbahnen zur Lackierung des Dachs der Kraftfahrzeugkarosserie gemäß Figur 1 im unteren Bereich von Figur 1,

Figur 3

eine Abwandlung von Figur 2,

Figur 4

eine schematische Darstellung eines Übergangsabschnittes einer Lackierbahn,

Figur 5

eine Abwandlung von Figur 4,

Figur 6

eine schematische Darstellung einer erfindungsgemäßen Lackieranlage,

Figur 7

eine schematische Darstellung zur Lackierung mit parallelen Lackierbahnen gemäß dem Stand der Technik, was zu unbeschichteten Bereichen führt, sowie

Figur 8

eine schematische Darstellung von nebeneinanderliegenden Lackierbahnen mit Überlappungen zwischen den benachbarten Lackierbahnen gemäß dem Stand der Technik.

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 embodiments of the invention with reference to FIGS. Show it:

FIG. 1

a view of a roof of a motor vehicle body, wherein the roof is to be painted,

FIG. 2

a schematic representation of adjacent paint paths for painting the roof of the vehicle body according to FIG. 1 in the lower part of FIG. 1,

FIG. 3

a modification of FIG. 2 .

FIG. 4

a schematic representation of a transition section of a painting,

FIG. 5

a modification of FIG. 4 .

FIG. 6

a schematic representation of a paint shop according to the invention,

FIG. 7

a schematic representation of the painting with parallel Lackierbahnen according to the prior art, which leads to uncoated areas, as well as

FIG. 8

a schematic representation of adjacent Lackierbahnen with overlaps between the adjacent Lackierbahnen according to the prior art.

In the following description of the invention is to avoid repetition of the FIGS. 7 and 8 Referring to show the conventional coating method. In the following, therefore, the same reference numerals are used for corresponding details.

The Figures 1 and 2 show a schematic representation of the painting of a roof 9 of a motor vehicle body by means of an application device, which generates an approximately rectangular spray pattern 2, as in FIG. 2 is shown.

The painting of the roof 9 is problematic because the roof 9 is not rectangular, but has curved side edges 10. It is therefore not possible to simply paint the roof 9 with parallel coating webs 1, since this leads to uncoated areas 6 (cf. Fig. 7 ) or over-coated areas 8 (cf. Fig. 8 ) would lead.

The invention therefore provides that the application device is rotated along the path 3, specifically around the beam axis of the applied coating agent jet, as a result of which the spray pattern 2 rotates accordingly. So shows FIG. 2 in each case an angle of rotation α between the longitudinal direction 11 of the elongated spray pattern 2 on the one hand and a web transverse direction 12 on the other hand, wherein the web transverse direction is oriented at right angles to the web 3 course. Out FIG. 2 It can be seen that the angle of rotation α of the spray pattern 2 along the path 3 is changed in order to adapt the web width so that the coating webs 1 adjoin one another without gaps and without overlapping and thereby conform to the component edges 10.

FIG. 3 shows a modification of FIG. 2 with another adjustment of the twist angle α along the track 3. Again, however, the entire roof 9 is painted without overlapping and without gaps between the adjacent coating webs 1.

FIG. 4 shows a schematic representation of the transition from a web section 13 with a maximum web width SB1 a web section 14 having a much smaller web width SB3.

Between the two track sections 13, 14 there is a transition section 15 with a track width SB2, which is adapted from a value SB2 = SB1 at the beginning of the track section 15 to a value SB2 = SB3 at the end of the transition section 15. For this adjustment of the web width SB2 each of the spray pattern 2 is rotated, as in FIG. 4 is shown, wherein different rotational angle states along the path 3 are shown.

In the transition section 15 is not only a change in the rotation angle α2 = α1 = 0 ° to α2 = α3. In addition, in the transition section 15, the travel speed of the application device along the path 3 is adjusted. This ensures that the layer thickness of the change in the angle of rotation α between the web portion 13 and the web portion 14 is unaffected. Thus, the travel speed V3 in the web section 14 is calculated as a function of the travel speed V1 in the web section 13 and the twist angle .alpha.3 in the web section 14 according to the following formula: $$\mathrm{<figure-callout\; id="3"\; label="V"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}3=\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}1/\mathrm{<figure-callout\; id="3"\; label="cos\; \alpha "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">cos\; </figure-callout>}\left(\mathrm{\alpha }\right)\left(\mathrm{}3\right),$$

wobei S2 die Länge des Übergangsabschnitts 15 entlang dem Bahnverlauf 3 ist.In the transition section 15, the application device thus experiences an acceleration a2, which is calculated as follows: $$\mathrm{a}2={\left(\mathrm{V}3-\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}1\right)}^2/\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">S</figure-callout>}\mathrm{2,}$$

where S2 is the length of the transition section 15 along the track 3.

In the transition section 15, the application device and thus also the spray pattern 2 are rotated at a twisting speed ω2, which depends on the layer thickness tolerance ΔSD%, the travel speed V1 in the web section 15 and the web width SB1 in the web section 13 and can be calculated according to the following formula: $$\mathrm{<figure-callout\; id="2"\; label="\omega "\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\omega </figure-callout>}2=\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="imgf0002.png"\; state="\{\{state\}\}">V</figure-callout>}1/\mathrm{<figure-callout\; id="1"\; label="SB"\; filenames="imgf0002.png"\; state="\{\{state\}\}">SB</figure-callout>}1\cdot \mathrm{\Delta SD}\%\cdot 360°/\mathrm{\pi },$$

FIG. 5 shows a modification of FIG. 4 so that reference is made to the above description to avoid repetition. A special feature here is that the path 3 is not exactly linear, but experiences a lateral offset in the transition section 15.

Finally shows FIG. 6 in a greatly simplified, schematic form a painting according to the invention for carrying out the above-described coating process according to the invention.

The painting plant consists essentially of a multi-axis painting robot 16, which can be carried out in a conventional manner and therefore need not be described in detail.

The painting robot 16 is controlled by a robot controller 17, wherein the robot controller 17 also controls an application device 18, which is positioned in front of the painting robot 16. The robot controller 17 now controls the painting robot 16 in such a way that the application device 18 is guided in adjacent coating paths over a component surface 19 to be painted, as has already been described in detail above.

During this movement of the application device 18, the robot controller 17 controls the painting robot 16 such that the application device 18 can be rotated about a beam axis 20 of the coating agent beam in order to be able to adapt the web width of the applied coating web, as has already been described in detail above.

The invention is not limited to the preferred embodiments described above. Rather, a variety of variants and modifications is possible, which also make use of the inventive idea and therefore fall within the scope. In particular, the invention also claims protection of the subject matter and the features of the dependent claims independently of the claims referred to and in particular without the characterizing feature of the main claim.

LIST OF REFERENCE NUMBERS

1

coating tracks

2

spray pattern

3

trajectory

4

component edge

5

component edge

6

Uncoated area of the component surface

7

Longitudinal direction of the spray pattern

8th

Overcoated area

9

Roof of a motor vehicle body

10

Side edge of the roof

11

Longitudinal direction of the elongated spray pattern

12

Cross-web direction

13

Web section with maximum web width

14

Web section with narrow web width

15

Transition section

16

Painting robots

17

robot control

18

applicator

19

component surface

20

Beam axis of the coating agent jet

α

Angle of rotation between the longitudinal direction of the spray pattern and the web transverse direction

α1

Angle of rotation in the web section 13

α2

Angle of rotation in the web section 15

α3

Twist angle in the web section 14

ω

Rotation speed of the application device

v

Travel speed of the application device

SB1

Maximum web width in the web section 13

SB2

Web width in the web section 15

SB3

small web width in the web section 14

Claims (11)

1. Coating method for coating components, in particular for coating motor vehicle bodywork components in a painting installation, comprising the following steps:

   a) moving an application device (18) along a predetermined coating path (1) over a component surface (9, 19) to be coated,

   b) applying a coating medium stream (20) by means of the application device (18) onto the component surface (9, 19),

   b1) wherein the coating medium stream (20) is applied while the application device (18) is moved over the component surface (9, 19) and

   b2) wherein the coating medium stream (20) is not rotationally symmetrical relative to its stream axis (20) and therefore generates on the component surface (9, 19) an elongate spray pattern (2) with a particular longitudinal direction (7),

   c) rotation of the application device (18) about the stream axis (20) relative to the coating path (1) during the movement of the application device (18) so that the angular position (α) of the longitudinal direction (7) of the spray pattern (2) changes along the coating path (1) relative to the path transverse direction,

   characterized in that

   d) the component surface (9, 19) to be coated as a whole is not exactly rectangular,

   e) in that the coating medium is applied along a plurality of mutually adjacently arranged coating paths (1) on the component surface (9, 19),

   f) in that the individual coating paths (1) are not exactly rectangular, in order to adapt to the non-rectangular component surface (9, 19), and

   g) in that during the movement along the not exactly rectangular coating paths (1), the application device (18) is rotated about the stream axis (20) in order to rotate the elongate spray pattern (2) such that the desired path width (SB1, SB2, SB3) is achieved.
2. Coating method according to claim 1,
   characterised in that

   a) the application device (18) is rotated about the stream axis (20) through a particular rotation angle (α) between the longitudinal direction (7) of the spray pattern (2) and the path transverse direction in order to achieve a desired path width (SB1, SB2, SB3),

   b) in that the application device (18) is moved at a particular movement speed along the coating path (1), and

   c) in that the application device (18) applies the coating medium with a particular coating medium flow, and

   d) in that the movement speed and/or the coating medium flow is adjusted dependent upon the rotation angle (α) in order to compensate for the effect of the rotation on the layer thickness.
3. Coating method according to claim 2, characterised in that the adjustment of the movement speed of the application device (18) dependent upon the rotation angle (α) of the application device (18) is carried out in accordance with the following formula: $$\mathrm{V}\left(\mathrm{\alpha }\right)=\mathrm{V}0/\cos \left(\mathrm{\alpha }\right)$$

   

   where

   V0 is the movement speed of the application device (18) when the rotation angle (α) between the longitudinal direction (7) of the spray pattern (2) and the path transverse direction is zero,

   α is the rotation angle (α) between the longitudinal direction (7) of the spray pattern (2) and the path transverse direction,

   V(α) is the adjusted movement speed at the current rotation angle (α).
4. Coating method according to one of the preceding claims, characterised in that

   a) the application device (18) is moved by a multi-axis application robot over the component surface (9, 19),

   b) in that the operation of the application device (18) and of the application robot (16) is controlled by a parameter set,

   c) in that the parameter set is adjusted during the movement along the coating path (1).
5. Coating method according to claim 4, characterised in that the parameter set comprises at least one of the following parameters for controlling the application device and the application robot:

   a) the movement speed of the application device (18) along the coating path (1),

   b) the acceleration of the application device (18) along the coating path (1),

   c) the rotation angle (α) of the application device (18) between the longitudinal direction (7) of the spray pattern (2) and the path transverse direction,

   d) the rotation speed (ω) of the application device (18),

   e) the coating medium flow that is applied,

   f) the coating spacing between the application device (18) and the component surface (9, 19).
6. Coating method according to claim 4 or 5,
   characterised in that

   a) the parameter set for controlling the application device (18) and the application robot (16) along the coating path (1) is continuously adjusted, or

   b) in that the coating path (1) is subdivided into a plurality of successive path portions situated one after another and the parameter set for controlling the application device (18) and the application robot (16) within the individual path portions is kept constant and is changed between the path portions.
7. Coating method according to one of the preceding claims, characterised by the following steps for a spray pattern (2) which has a particular spray width (SB1) in the longitudinal direction (7):

   a) stipulation of a desired path width (SB2) of the coating path (1),

   b) rotation of the application device (18) about the stream axis (20) so that the longitudinal direction (7) of the spray pattern (2) is angled by a rotation angle (α) relative to the path transverse direction,

   c) calculation of the rotation angle (α) dependent upon the desired path width (SB2) and the spray width (SB1), in particular according to the following formula: $$\mathrm{\alpha =arccos}\left(\mathrm{SB}2/\mathrm{SB}1\right),$$

   

   where

   SB1 is the width of the spray pattern (2) along the longitudinal direction (7) of the spray pattern (2),

   SB2 is the desired path width of the coating path (1),

   α is the rotation angle between the longitudinal direction (7) of the spray pattern (2) and the path transverse direction.
8. Coating method according to one of the preceding claims, characterised in that

   a) the coating path (1) for adjustment of the path width comprises a transition portion (15) with a portion length S2,

   b) in that at the start of the transition portion (15) the path width is SB1, the movement speed is V1 and the rotation angle is α1,

   c) in that within the transition portion (15) the path width is SB2, the movement speed is V2, the acceleration is a2, the rotation angle is α2 and the rotation speed is ω2,

   d) in that at the end of the transition portion (15) the path width is SB3, the movement speed is V3 and the rotation angle is α3,

   e) in that the rotation angle α3 at the end of the transition portion (15) is calculated dependent upon the following variables:

   - path width SB1 at the start of the transition portion (15),

   - path width SB3 at the end of the transition portion (15),
   in particular according to the formula: $$\mathrm{\alpha }3=\arccos \left(\mathrm{SB}3/\mathrm{SB}1\right)$$

   

   f) in that the movement speed V3 at the end of the transition portion (15) is calculated dependent upon the following variables:

   - rotation angle α3 at the end of the transition portion (15),

   - movement speed V1 at the start of the transition portion (15),
   in particular according to the formula: $$\mathrm{V}3=\mathrm{V}1/\cos \left(\mathrm{\alpha }3\right)$$

   

   g) in that the acceleration a2 within the transition portion (15) is calculated dependent upon the following variables:

   - movement speed V1 at the start of the transition portion (15),

   - movement speed V3 at the end of the transition portion (15),

   - portion length S2 of the transition portion (15), in particular according to the formula: $$\mathrm{a}2={\left(\mathrm{V}3-\mathrm{V}1\right)}^2/\mathrm{S}2$$

   

   h) in that the portion length S2 of the transition portion (15) is calculated dependent upon the following variables:

   - rotation angle α3 at the end of the transition portion (15),

   - movement speed V1 at the start of the transition portion (15),

   - movement speed V3 at the end of the transition portion (15),

   - rotation speed ω2 in the transition portion (15), in particular according to the formula: $$\mathrm{S}2=\left[\mathrm{\alpha }3\cdot \left(\mathrm{V}3-\mathrm{V}1\right)\right]/\mathrm{\omega }2$$

   

   i) in that the rotation speed ω2 in the transition portion (15) is calculated dependent upon the following variables:

   - movement speed V1 at the start of the transition portion (15),

   - percentage layer thickness tolerance ΔSD%,

   - path width SB1 at the start of the transition portion (15),
   in particular according to the formula: $$\mathrm{\omega }2=\mathrm{V}1/\mathrm{SB}1\ast \mathrm{\Delta SD}\%\ast \left(360°\right)/\mathrm{\pi }.$$

   
9. Coating method according to one of the preceding claims, characterised in that

   a) the application device (18) is continuously rotated during the movement along the coating path (1), and

   b) in that the spray pattern (2) is sharp-edged, and

   c) in that the spray pattern (2) is substantially rectangular, and

   d) in that the application device (18) is guided over the component surface (9, 19) such that at the impact point of the coating medium stream (20), the coating medium stream (20) is oriented substantially perpendicularly to the component surface (9, 19).
10. Coating installation, in particular for carrying out the coating method according to one of the preceding claims, comprising

    a) an application device (18) for applying a coating medium stream (20) onto a component surface (9, 19), wherein the coating medium stream (20) is not rotationally symmetrical relative to its stream axis (20) and therefore generates on the component surface (9, 19) an elongate spray pattern (2) with a particular longitudinal direction (7),

    b) an application robot (16) for guiding the application device (18) along a pre-defined coating medium path over the component surface (9, 19), and

    c) a robot control system (17) for controlling the application robot (16),

    d) wherein the robot control system (17) rotates the application device (18) about the stream axis (20) during the movement along the coating path (1), so that the rotation angle (α) changes along the coating path (1) between the longitudinal direction (7) of the spray pattern (2) and the coating path (1),

    characterised in that

    e) the component surface (9, 19) to be coated as a whole is not exactly rectangular,

    f) the robot control system (17) controls the application robot (16) such that

    f1) the coating medium is applied along a plurality of mutually adjacently arranged coating paths (1) on the component surface (9, 19),

    f2) the individual coating paths (1) are not exactly rectangular, in order to adapt to the non-rectangular component surface (9, 19), and

    f3) during the movement along the not exactly rectangular coating paths (1), the application device (18) is rotated about the stream axis (20) in order to rotate the elongate spray pattern (2) such that the desired path width (SB1, SB2, SB3) is achieved.
11. Coating installation according to claim 10,
    characterised in that

    a) the robot control system (17) controls the application robot such that the application device (18) is moved at a particular movement speed along the coating path (1) over the component surface (9, 19), and

    b) in that the robot control system (17) adjusts the movement speed of the application device (18) dependent upon the rotation angle (α) between the longitudinal direction (7) of the spray pattern (2) and the path transverse direction.

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