EP2496364B1 - Coating method and coating system having dynamic adaptation of the atomizer rotational speed and the high voltage - Google Patents

Description

The invention relates to a coating method and a corresponding coating system for coating components with a coating agent, in particular for the coating of motor vehicle body components with a paint.

In modern paint shops for painting motor vehicle body components multiaxial painting robots are usually used, which lead a rotary atomizer as an application device. The painting robot guides the rotary atomizer along programmed pathways over the component surface, whereby the webs are typically lined up in a meandering manner. Alternatively, however, there is also the possibility that the component to be coated is moved past the atomizer by means of suitable conveyor technology or by a robot. In contrast to the previously used painting machines (for example roofing machines and side machines), such painting robots are very flexible in their web guide. In addition, the number of rotary atomizers can be greatly reduced by the use of painting robots, but this leads to higher demands on the area performance and thus also on the coating speed.

During the movement of the rotary atomizer by the painting robot, the outflow quantity (ie the paint stream) and the shaping air flow are changed dynamically in order to achieve an optimum painting result to reach. For example, little or no steering air is applied when a large-scale painting is desired, for example, in the painting of large-area components (eg hood, roof surface) of motor vehicle body components. In a detail painting, however, a relatively large Lenkluftstrom is delivered to constrict the spray.

In contrast, in the conventional painting plants, the rotational speed of the rotary atomizer and the high voltage of the electrostatic coating agent charging were kept constant by a control. In the known paint shop so no dynamic adjustment of speed and high voltage, but only a dynamic adjustment of the fluid operating variables, such as paint flow and Lenkluftstrom took place during the movement of the atomizer. Although the high voltage of the electrostatic coating agent charging can also be changed in the known paint shops, this was not possible dynamically, but only between successive motor vehicle bodies.

A disadvantage of the conventional painting is therefore the unsatisfactory flexibility and dynamics in painting.

Out EP 1 380 353 A1 are a coating method and a coating system according to the preamble of the independent claims known. However, a highly dynamic adaptation of the high voltage for the electrostatic coating agent charging is only possible to a limited extent.

Furthermore, it should be noted on the prior art EP 2 085 846 A2 . DE 10 2007 026 041 A1 . WO 2005/042173 A1 . US 2001/0020653 A1 . WO 2008/037456 A1 and EP 1 245 292 A1 ,

The invention is therefore based on the object to provide a correspondingly improved paint shop.

This object is achieved by an inventive coating method and a corresponding coating system according to the independent claims.

The invention is based on the technical knowledge that it is advantageous in the operation of a paint shop when during the movement of the atomizer not only the fluidic operating variables (eg paint flow, Lenkluftstrom) are changed dynamically, but also electrical and / or kinematic operating variables, such as the rotational speed of the rotary atomizer or the high voltage, with which the coating agent to be applied is charged electrostatically.

As has already been explained above, the dynamic change of the electrical and / or kinematic operating variables such as high voltage and / or rotational speed typically takes place during painting or coating, ie within the coating path predetermined by the program control of the coating system, along which the rotary atomizer is usually removed from the painting process. or coating robot is moved over the component surface during the application. On this coating path, it is known to specify predetermined path points defined by the program control, for example in the teach method or in another manner, for each of which the required (designated as brush) sets of operating quantities can be adjusted and changed according to the surface geometry of the component to be coated. In particular, according to the invention, the said electrical or kinematic operating variables can thus also be changed at these defined path points. Such changes are also conceivable at other locations related to the defined track points, for example when interpolating between adjacent track points.

Up to now, for various reasons, it has usually not been attempted to dynamically change the speed and the high voltage during operation of the paint shop.

On the one hand, the drive of conventional rotary atomizers usually takes place pneumatically by turbines in which However, the possible braking effect is much lower than the possible acceleration effect. It is therefore very difficult control technology, the turbine to control so that the speed of the rotary atomizer follows a certain speed curve. In addition, the rotational speed dynamics of the rotary atomizer are influenced by numerous factors, such as the available air pressure to drive the turbine, the mass of the bell cup, which can vary depending on the material used (aluminum, steel or titanium), the diameter of the bell cup, the current amount of varnish to be applied, the viscosity and the solids content and the mass of the varnish.

On the other hand, dynamic changes in the electrostatic high voltage in the operation of the paint shops have not been considered, among other things, because such voltage changes depend on the electrical capacity of the coating agent charging, which is influenced by several factors that can change during operation. For example, the electrical capacity may vary depending on the type of paint and the humidity. In addition, the high-voltage cascades used generally have a more or less large hysteresis, which has hitherto also stopped by a dynamic change in the high voltage during operation of the paint shop. Depending on the application structure on the robot (eg 1K / 2K, number of colors, number of rinsing agents, conductivity of the paint, hose cross-section), the electrical capacity of the paint shop changes. Almost every system therefore has different electrical capacities that have to be taken up and taken down by the high-voltage cascade. However, the inertia of the electrical operating variables increases with the electrical capacity of the paint shop. A prediction of the behavior of the plant is therefore difficult and a simulation of the painting results therefore also. In the conventional paint shops, therefore, attempts have been made so far to keep the electrical operating variables constant.

The invention now provides that in the operation of a coating system, the rotational speed of the rotary atomizer and / or the high voltage of the electrostatic coating agent charging is dynamically adjusted, i. during the movement of the atomizer along the given painting path. This is to be distinguished from a virtually static change in the speed or the high voltage between successive Lackiervorgängen. The term dynamic change used in the context of the invention therefore preferably refers to the fact that the electrical and / or kinematic operating variable (for example rotational speed, high voltage) is changed within a painting track. Moreover, within the scope of the invention it is also possible to dynamically change further operating variables (for example guide air flow, paint flow, outflow quantity, robot speed) of the atomizer or the paint shop, such as, for example, fluid operating variables.

An advantage of the invention is the higher dynamics, whereby a faster painting is possible, which in turn leads to shorter cycle times and thus reduces the unit cost (CPU: C ost p er U nit) during painting.

Another advantage of the invention is the improved coating result or a higher paint quality.

In addition, the dynamic adjustment of electrical operating variables (eg high voltage) allows a reduction in the number of high-voltage flashovers, resulting in fewer operational disturbances, which in turn is the so-called first-run rate improved, ie the error rate at the first run of the paint shop.

Furthermore, the invention advantageously allows air savings and thus a reduction in the unit cost (CPU) during painting.

In a preferred embodiment of the invention, the dynamics of the change in the electrical and / or kinematic operating variable (eg speed, high voltage) and / or the fluidic operating variable (eg paint flow, Lehklüftstrom) of the atomizer is so large that at a setpoint change, the response time is less than 2s , 1s, 500ms, 300ms, 150ms, 100ms, 50ms, 30ms or even less than 10ms. The set time is the time required for a setpoint change to convert at least 95% of the setpoint change.

The term used in the context of the invention of an electrical and / or kinematic operating variable is preferably based on the rotational speed of the rotary atomizer and the high voltage of an electrostatic coating agent charging. In the context of the invention, there is the possibility that only the rotational speed is changed dynamically, while the high voltage is set in a conventional manner. Furthermore, there is a possibility that only the high voltage is changed dynamically while the rotational speed is set in a conventional manner. Preferably, however, both the rotational speed and the high voltage are changed dynamically. It should also be mentioned that the term used in the context of the invention of an electrical and / or kinematic operating variable is not limited to the rotational speed of the rotary atomizer and the high voltage of the electrostatic coating agent charging, but also others electrical or kinematic operating variables of the atomizer or paint shop includes. For example, within the scope of the invention it is also possible for the electric current of the electrostatic coating agent charge to be changed dynamically, which is advantageous in particular when the coating agent is charged by means of external charging, ie by means of external electrodes.

Furthermore, the term used in the context of the invention of a fluidic operating variable preferably depends on the paint stream and the Lenkluftstrom, wherein in the case of several separate Lenkluftströme they can be dynamically adjusted independently of each other. However, the term of a fluidic operating variable used in the context of the invention is not limited to the steering air flow and the paint flow, but fundamentally also includes other fluidic operating variables of the atomizer or the paint shop.

The main idea of the invention is that the operating variables are no longer kept constant, as in the prior art, by the additional dynamics in the rotational speed and high-voltage control, but that they are highly dynamic in the brush change (previously outflow quantity and steering clearances) for optimum painting eg the interior areas, but also the outdoor areas and detail areas can be parameterized.

Preferably, control by painting rules and data fields is so intelligent that it is able to automatically change the correct parameter to optimally adapt to the spot to be painted. An acceptable quality, highest efficiency and highest coating speed should be achieved. However, one can also imagine that the controller should be ranked by the optimization priorities pretend. Then you could focus on shortest painting time, highest efficiency, lowest Lackierverbrauch, lowest discharge rate, conservation of the robot (possible undynamic driving the robot), lowest risk of high voltage risk, best layer thickness distribution, lowest Lackstörungsrisiko (runners, cooker), control of the degree of wetness of the paint, color etc., lay.

In a preferred embodiment of the invention, a state variable of the coating system is continuously determined during the movement of the atomizer, wherein the state variable can reproduce, for example, the geometry of the component surface at the Farbauftreffpunkt. This state variable is then used for the dynamic adaptation of the electrical and / or kinematic operating variable and / or the fluidic operating variable. This means that the change in the electrical and / or kinematic operating variable and / or the fluidic operating variable takes place as a function of the determined state variable in order to optimize the coating result.

The determination of the state variable can be done within the scope of the invention, for example by a measurement. However, it is alternatively also possible for the state variable of interest to be available in any case as a control variable in a control device and then only has to be read out.

For example, as already briefly mentioned above, the state variable which is taken into account in the dynamic adaptation of the electrical and / or kinematic operating variable and / or the fluidic operating variable, reproduce the geometry of the component at the ink impact point. So is in a paint larger area, essentially level Component surfaces a widely fanned spray desirable to achieve a large area performance, so that the shaping air is then switched off expediently. In addition, then a relatively large paint stream can be selected to allow a correspondingly large area performance, the large paint stream can then be applied only with a correspondingly high speed of the rotary atomizer. Furthermore, when painting large-area, substantially flat component surfaces, the high voltage can be chosen to be relatively large, since the risk of electrical flashovers is then relatively low. In the case of a coating of strongly curved component surfaces, on the other hand, a relatively strongly constricted spray jet is desirable, so that a relatively large directing air flow is selected. In addition, the high voltage of the coating agent charging should then be relatively small in order to avoid electrical flashovers.

Furthermore, there is the possibility that the state variable, which is taken into account in the dynamic adaptation of the operating variables, indicates whether an interior painting or exterior painting takes place. Thus, in a interior painting of an interior of a motor vehicle body component usually a strong constricted spray is desirable, whereas in a exterior painting of outer surfaces of a motor vehicle body component usually a relatively strong fanned spray is desirable, resulting in correspondingly different demands on the Lenkluftstrom. In addition, interior painting and exterior paint also differ in the requirements of the high voltage of the coating agent charging, since, for example, in an interior at best a relatively small high voltage is possible to avoid flashovers.

Furthermore, it is within the scope of the invention, the possibility that the state variable, which is taken into account in the dynamic adjustment of the operating variables, indicates whether the coating is currently done with or without electrostatic charging of the coating composition.

Another possibility is that the state variable represents the distance between the color impingement point and an electrical earth point at which the component to be coated is electrically grounded. For example, when painting plastic parts (such as bumpers), geometry and dynamics are also critical, as they are partially painted on electrically grounded components and partly on electrically insulated components, but fixed with steel fixtures. The electrical current of the electrostatic coating agent charge is then dissipated via the wet paint to a ground point that is in communication with the device. At each different point in the geometry, the isolation or proximity to the earth point must be taken into account, so that dynamic adaptation of the high voltage as a function of the distance to the earth point brings advantages.

Furthermore, it is within the scope of the invention, the possibility that the state variable, which is taken into account in the dynamic adjustment of the operating variables, indicating whether the respective component is a plastic component or a component made of an electrically conductive material, which to the above leads mentioned advantages.

Another possibility is that the state variable, which is taken into account in the dynamic adaptation of the operating variables, indicates whether a detailed painting or surface coating is currently taking place. So insist on one Detail painting on the one hand and in a surface painting on the other hand, different requirements for paint flow, Lenkluftstrom, speed and high voltage coating agent charging.

Furthermore, the state variable taken into account in the dynamic adaptation of the operating variables may reflect whether the nebulizer is currently being cleaned or whether the nebulizer is being used to apply paint. Thus, when cleaning the atomizer on the one hand and when using the atomizer for the application of paint on the other hand, different requirements for paint flow, Lenkluftstrom, speed and high voltage of the coating agent charging.

The above-mentioned examples of the state variable can also be combined with one another within the scope of the invention. For example, the operating variables can be adjusted dynamically as a function of a plurality of the state variables mentioned above by way of example. Moreover, the invention is not limited to the above-mentioned examples with regard to the state variables considered for dynamic adaptation, but in principle can also be implemented with other state variables.

In addition, within the scope of the invention, the possibility of an automatic adjustment of the operating variables by software. For example, an operating quantity (e.g., spray jet width) may be changed, after which the other operating quantities (e.g., draft air, paint stream), paint speed, high voltage, speed) are replenished.

In a first example of such an automatic parameter adjustment, a geometry factor which determines the geometry of the atomizer is continuously determined during the movement of the atomizer Component surface at the color impact point reproduces. Depending on this geometry factor, the spray jet width is then adjusted accordingly, which then in turn leads to a corresponding adaptation of steering air flow, paint flow and / or coating speed (ie movement speed of the atomizer).

In a second example of the automatic parameter adjustment, the high voltage on the painting web is changed in an interior painting due to the particular component shape, which automatically leads to a corresponding adjustment of the paint stream (outflow) and the shaping air.

The adaptation of the parameters or the operating variables taking place in the two examples mentioned above by way of example can be carried out automatically by software or by a control program. However, there is also the possibility that the control program merely makes a proposal for adaptation, which can then be implemented by a programmer (teacher) or a plant operator.

According to the invention, the high voltage for the electrostatic coating agent charging is generated by means of a high voltage cascade, wherein a rapid reduction of the high voltage can be made by the high voltage cascade is connected by means of a Ableitschalters or a ground switch directly or via a bleeder to ground. Cascade type high voltage generators for electrostatic coating equipment are well known in the art and have long been common ( US 6,381,109 . US 4,266,262 , etc.) and essentially comprise a multistage high-voltage cascade connected downstream of a high-voltage transformer gate, whose stages consist of diodes and capacitors. A particularly convenient option extremely faster, virtually delay-free According to the invention, changes in the high voltage consist in replacing the diodes of conventional cascades with high-voltage-resistant photodiodes which can be controlled by illumination and by whose light control the cascade and, suitably, each individual cascade stage can be switched on and off to change the high voltage or controlled with respect to its current.

Furthermore, it is within the scope of the invention, the possibility that the rotary atomizer is driven by an electric motor, such as from WO 2008/037456 is known per se, to allow a large speed dynamics.

Alternatively, however, there is also the possibility that the rotary atomizer is hydraulically driven to allow the required speed dynamics.

Here, an electrical electrical isolation can be provided in addition to the rotary atomizer, in order to allow electrostatic coating agent charging despite the electric or hydraulic drive of a lying at high voltage potential in operation rotary atomizer. Possibilities for this are described in the abovementioned WO document.

Preferably, however, the drive of the rotary atomizer is carried out in a largely conventional manner pneumatically by a turbine. Preferably, the turbine can not only accelerate by means of compressed air, but also actively decelerate by means of compressed air in order to achieve the required speed dynamics. For this purpose, it may be expedient, for example, for the turbine wheel of the drive turbine to accelerate desired positive or negative rotational speed changes via one or more several supply and disconnectable additional supply channels to supply additional drive or braking medium (eg air), as in principle of itself EP 1 245 292 B1 is known.

It should also be mentioned that for the first time the invention makes it possible for the electrical and / or kinematic operating variables (for example rotational speed, high voltage) of the atomizer to be changed in synchronism with the fluidic operating variables (for example guide air flow, paint flow). This means that these different operating variables react synchronously to the setpoint change during a setpoint change.

It should also be mentioned that the term of movement of the atomizer used in the context of the invention may have different meanings. A meaning of this term provides that the component to be coated stands still while the atomizer is moved over the component surface of the stationary component. On the other hand, another meaning of this term is that the atomizer stands still while the component with the component surface to be coated is moved along the atomizer. On the other hand, a third meaning of this term provides that both the atomizer and the component to be coated are moved during the coating and thereby perform a relative movement.

Finally, it should be mentioned that the invention also encompasses a suitably adapted coating system which is suitable for a dynamic adaptation of the electro / kinematic operating variables (for example rotational speed, high voltage).

Figuren 1A-1C

das erfindungsgemäße Verfahren zur dynamischen Anpassung der Betriebsgrößen des Zerstäubers in Form eines Flussdiagramms,

Figur 2

ein erstes Beispiel einer automatischen Parameteranpassung in Form eines Flussdiagramms,

Figur 3

ein zweites Beispiel einer automatischen Para-meteranpassung in Form eines Flussdiagramms, sowie

Figur 4

eine stark vereinfachte Darstellung einer erfindungsgemäßen Lackieranlage.

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

Figures 1A-1C

the method according to the invention for the dynamic adaptation of the operating variables of the atomizer in the form of a flow chart,

FIG. 2

a first example of automatic parameter adaptation in the form of a flow chart,

FIG. 3

a second example of an automatic parameter adjustment in the form of a flow chart, as well

FIG. 4

a greatly simplified illustration of a paint shop according to the invention.

The Figures 1A-1C show the method steps according to the invention of a coating method in the form of a flow chart. In this exemplary embodiment, the coating method is used for painting motor vehicle body components in a paint shop, wherein the painting is carried out by rotary atomizers, which are each guided by a multi-axis painting robot. Furthermore, it should be mentioned that the process steps described in more detail below are repeated continuously in the painting operation in order to enable a dynamic adaptation of the operating variables of the rotary atomizer.

In a first step S1, it is first determined whether an interior painting of an interior of a motor vehicle body component takes place or an exterior painting of exterior surfaces of the motor vehicle body component. This distinction is important because, in the case of interior painting on the one hand and exterior painting on the other hand, different requirements apply to the operating variables (eg guide air flow, High voltage) of the rotary atomizer. Thus, in a exterior paint usually a wide-spread spray makes sense to paint as large as possible can. In contrast, in a interior painting a relatively strong constricted spray is desirable in order to paint more detailed.

In a next step S2, a branch to a step S3 or a step S4 then takes place, depending on the type of coating (interior painting or exterior painting).

In the case of interior painting, a corresponding flag IL = 1 is set in step S3.

In the case of exterior painting, on the other hand, the flag IL is cleared in the step S4, IL = 0. The flag IL thus indicates whether interior painting or exterior painting is to be carried out, so that the flag IL is then stored for later consideration in the dynamic adjustment of the operating quantities (for example guide air flow, paint flow, speed, high voltage) of the rotary atomizer.

Subsequently, it is determined in a step S5 whether a detailed painting or a surface coating should take place. This distinction is also important because different requirements are placed on the spray jet on the one hand and on surface painting on the other hand. Thus, in a detail painting a strongly constricted spray is desirable, whereas in a surface painting a highly fanned spray is sought, which is associated with correspondingly different demands on the steering air flow.

In a step S6, a branch to a step S7 or a step S8 then takes place, depending on the type of coating (detailed painting or surface painting).

In the case of a detail painting, a corresponding flag DL = 1 is set in step S7.

In the case of surface painting, on the other hand, the flag DL is cleared in step S28. DL = 0. The flag DL thus indicates whether a detail painting or a surface painting is carried out so that the flag DL is stored for later consideration in the dynamic adaptation of the operating variables (for example speed, steering air flow, paint flow, high voltage) of the rotary atomizer.

In a next step S9 it is then determined whether the coating is to take place with an electrostatic coating agent charge or without an electrostatic coating agent charge. This distinction is important because a minimum distance to the grounded body component must be maintained in an electrostatic coating agent coating to avoid electrical flashovers. If, on the other hand, no electrostatic coating agent charging takes place, then there is also no risk of electrical flashovers, so that there are no restrictions in the positioning of the rotary atomizer in this respect.

In a step S10, a branch is then made depending on the activation or deactivation of the electrostatic (ESTA: electrostatic) coating agent charging to a step S10 or to a step S11.

In the case of electrostatic coating agent charging, a corresponding blade HS = 1 is set in step S10.

On the other hand, if no electrostatic coating agent charging is provided, the flag HS is cleared in step S11 HS = 0. The flag HS thus indicates whether electrostatic coating agent charging takes place or not in the painting operation, so that the flag HS is stored for later consideration in the dynamic adaptation of the operating variables (for example speed, high voltage, directing air flow, paint flow) of the rotary atomizer.

The flags IL, DL and HS are therefore state variables which reflect the current state of the paint shop, wherein these state variables can be adopted, for example, from the system control of the paint shop.

In a step S12, the desired spray jet width SB is then determined, which is also preprogrammed and can therefore usually be easily read from the associated program memory which controls the painting process. The spray jet width SB is the width of a coating path on the component surface, within which the layer thickness amounts to at least 50% of the maximum layer thickness.

In a further step S13, a geometry factor GF is then determined as the state variable, which reproduces the component geometry at the color impingement point. Thus, in the painting of essentially flat component surfaces, other requirements are imposed on the operating variables (eg steering air flow, paint flow, high voltage, rotational speed) of the rotary atomizer than in the coating of strongly curved component surfaces. The geometric factor GF can, for example, in the plant control (CAD: C omputer A ided D esign) from the stored CAD model of the part to be painted motor vehicle body are derived, so that no measurements are required to determine the geometry factor.

In a next step S14, the distance A between the ink impact point on the component to be painted on the one hand and the electrical end point of the component is then determined on the other hand, wherein the component is electrically grounded at the earth point. Thus, in the case of electrostatic coating agent charging, the electric current is dissipated via the wet paint towards the earth point, so that the insulation or the proximity to the end point should be taken into consideration at each different color impingement point in order to achieve an optimum painting result.

In addition, in a further step S15, the drawing speed v of the painting robot is determined, wherein the drawing speed v is the speed at which the painting robot moves the rotary atomizer over the component surface during painting. Thus, with a small pulling speed v, only a relatively small paint stream is required, whereas the paint stream must be correspondingly increased with increasing drawing speed v in order to achieve a constant layer thickness.

In a further step S16 it is then determined whether the component to be painted is a plastic component or a metal component, so that this distinction can also be taken into account in the dynamic adaptation of the operating variables (for example speed, high voltage, paint current, steering air flow).

In a step S17 then takes place depending on the type of the component to be painted (plastic component or metal component) a branch to a step S18 or a step S19.

In the case of a metal structural part, a corresponding flag MA = 1 is set in step S18 to indicate that the component to be painted is a metal component.

In the case of a plastic component, on the other hand, the flag MA is cleared in step S19. MA = 0.

Subsequently, it is determined in a step S20 whether the rotary atomizer is to be cleaned or whether the Rötationszerstäuber applied in the normal painting paint.

In a step S21 then, depending on the operating mode (cleaning or application), a branch takes place to a step S22 or to a step S23. In the case of a cleaning operation, a corresponding flag RB = 1 is set in step S22. In the case of normal application operation, on the other hand, the flag RB is cleared in step S23 RB = 0.

The above explained Figures 1A and 1B So show the determination of state variables of the paint shop, which should be considered in the dynamic consideration of the operating variables (eg speed, high voltage, paint flow, Lenkluftstrom) of the rotary atomizer in order to achieve an optimal painting result.

The Figure 1C with the steps S24-S28, however, shows how the operating variables (eg speed, high voltage, Lenkluftstrom, paint flow) of the rotary atomizer depending on the previously determined state variables (eg Geometry factor GF, spray jet width SB, etc.) are dynamically adjusted.

Thus, in step S24, a determination of the lacquer flow Q _LACK corresponds to a predetermined function f1 as a function of the previously determined state variables In. DL, HS, A, MA, RB, v, GF and SB. The function f1 can hereby be stored in the form of a characteristic field in the plant control.

In step S25, the steering _{air flow} Q _{STEERING AIR} is then _determined according to a function f2 as a function of the state variables IL, DL, HS, A, MA, RB, v, GF and SB, whereby the function f2 also takes the form of a characteristic map in the system control can be deposited.

In step S26, similarly, the high voltage U for the electrostatic coating agent charging in accordance with a function f3 is set in dependence on the previously determined state variables IL, DL, HS, A, MA, RB, v, GF and SB. The function f3 can also be stored in the form of a characteristic field in the system control.

In step S27, the rotational speed n of the rotary atomizer is then set according to a function f4 as a function of the previously determined state variables IL, DL, HS, A, MA, RB, v, GF and SB.

In step S28, the rotary atomizer is then driven by the electrical or kinematic operating _variables U and n and by the fluidic operating _variables Q _LACK and Q _{STEERING AIR} .

The above-described and in the Figures 1A-1C During the movement of the rotary atomizer, during the movement of the rotary atomizer, the _{process steps illustrated} are continuously repeated so that the operating _variables U, n, Q are _LACK and Q are _AIR of the rotary atomizer during the movement of the rotary atomizer are constantly dynamically adjusted in order to achieve an optimal painting result.

FIG. 2 shows a first example of automatic parameter adjustment by software.

Thus, in a first step S1, a geometry factor GF is determined, which reproduces the component geometry at the color impingement point.

In a next step S2, the spray jet width SB is then set as a function of the geometry factor GF in accordance with a predetermined function f1. Thus, in the case of a strongly curved component geometry, a correspondingly strongly constricted spray jet with a correspondingly small spray jet width SB is desirable. When painting a substantially planar component surface, however, a fanned spray with a correspondingly large spray jet width SB is desirable.

In a next step S3, the steering _{air flow} Q _{STEERING AIR} is then _set as a function of the desired spray jet _width SB in accordance with a predetermined function f2, wherein besides the desired spray jet width SB also other state variables can be taken into account, which is only schematically illustrated here.

In a further step S4, the paint stream Q _LACK is then determined as a function of the desired spray jet width SB in accordance with a predetermined function f3. Thus, with a large spray jet width SB, a correspondingly large paint flow Q _{LACK is} required in order to achieve the desired layer thickness.

The next step S5 then provides that the drawing speed v of the painting robot is set as a function of the desired spray jet width SB in accordance with a predetermined function f4.

In a step S6, the rotary atomizer is then controlled with the thus determined operating _variables Q _LACK , Q _LENKLUFT and the painting robot is moved with the optimized pulling speed v over the component surface.

In this example, therefore, the geometric factor GF is determined in order to derive therefrom the optimum spray jet width SB. The determination of the spray jet width SB then leads to a corresponding adaptation of the steering _{air flow} Q _{STEERING AIR} , the paint flow Q _LACK and the drawing speed v. This automatic parameter adjustment is continuously repeated during the operation of the painting robot during the movement of the rotary atomizer, so that the operating variables are adapted dynamically to the geometry of the component at the ink impact point.

FIG. 3 shows a second example of an automatic parameter adjustment during painting, wherein the in FIG. 3 shown process steps S1-S5 are continuously repeated during the painting operation during the movement of the rotary atomizer to allow a dynamic adjustment of the operating variables of the rotary atomizer.

In a first step S1, a geometry factor GF is again determined, which reproduces the component geometry at the color impingement point.

In step S2, the high voltage U for the electrostatic paint charging then becomes dependent on the geometry factor GF determined according to a predetermined function f1.

In addition, in a step S3, the paint flow Q _LACK is then determined as a function of the geometry factor GF in accordance with a predetermined function f2.

Furthermore, in step S4, the steering _{air flow} Q _{STEERING AIR is also defined} as a function of the geometric _factor GF in accordance with a predetermined function f3.

In step S5, the rotary atomizer is then driven with the operating _variables U, Q _LACK and Q _{STEERING AIR adjusted in this way} .

The above-described steps S1-S5 are continuously repeated during operation of the painting during the movement of the rotary atomizer to dynamically adjust the operating _variables U, Q _LACK and Q _{STEERING AIR} during the movement of the rotary atomizer to the component geometry in order to achieve an optimal painting result.

FIG. 4 shows in greatly simplified form a painting according to the invention with a multi-axis painting robot 1, which leads as an application device, an electrostatic rotary atomizer 2, as indicated by the dashed block arrow.

The painting robot is controlled by a robot controller 3, the robot controller 3 specifying the position of the tool center point (TCP) of the painting robot 1 and thereby moving the rotary atomizer 2 to predetermined, programmed painting paths.

The rotary atomizer 2, on the other hand, is controlled by a control unit 4, as will be described below.

Thus, for example, the rotary atomizer 2 has a steering _{air valve} 5, which is controlled by the control unit 4, so that the control unit 4 adjusts the steering _{air flow} Q _{STEERING AIR} , which is emitted by the rotary atomizer 2 for shaping the spray jet.

In addition, the rotary atomizer on a paint valve 6, which is controlled by the control unit 4, so that the control unit 4 by a suitable control of the paint valve 6 controls the paint flow Q _LACK , which is discharged from the rotary atomizer 2.

In addition, the rotary atomizer 2 has a pneumatic turbine 7, which drives a bell cup of the rotary atomizer 2. A special feature of the turbine 7 is that the turbine 7 can be pneumatically actively accelerated and braked to allow high speed dynamics. For this purpose, the control unit 4 can set an acceleration air flow Q ₊ and a brake air flow Q _{- in} order to set the desired rotational speed of the rotary atomizer 2. Complementary to this is already mentioned above EP 1 245 292 B1 to refer.

Furthermore, the rotary atomizer 2 has a high-voltage electrode 8 in order to electrostatically charge the applied coating agent, which leads to a high order winding rate. The high-voltage electrode 8 can be designed as an inner electrode or as an outer electrode, and is supplied by a high-voltage cascade 9 with a specific high voltage U, the high-voltage cascade 9 is also controlled by the control unit 4 in order to achieve the desired high voltage U.

In addition, the high-voltage cascade via a bleeder 10 and a bleeder 11 is connected to ground in order to reduce the high voltage U quickly. The diverter switch 11 is also controlled by the control unit 4, so that the high voltage U can be rapidly reduced, if this is desirable in the context of dynamic parameter adjustment. However, the high-voltage cascade can also be controlled in particular with photodiodes provided for this purpose, as has already been explained above.

Furthermore, the paint shop has a system controller 12, which communicates bidirectionally with the robot controller 3 and the control unit and supplies, for example, state variables of the paint shop to the control unit 4, so that the control unit 4 these state variables in the dynamic adaptation of the steering _{air flow} Q _{STEERING AIR} , the paint stream Q _LACK , the acceleration air Q ₊ , the brake air Q and the high voltage U can take into account.

The invention is not limited to the preferred embodiments described above. Rather, a variety of variants and modifications are possible, which also make use of the concept of the invention and therefore fall within the scope.

LIST OF REFERENCE NUMBERS

1

Painting robots

2

rotary atomizers

3

robot control

4

control unit

5

Directing air valve

6

paint valve

7

turbine

8th

High-voltage electrode

9

High voltage cascade

10

bleeder

11

dissipating

12

system control

Claims (18)

1. A coating method for coating a component surface of a component with a coating agent using an atomizer (4) in a coating installation, in particular for painting a motor vehicle body part with a paint,
   with the following steps:

   a) moving the atomizer (4) over the component surface of the component to be coated and, in this process,

   b) applying the coating agent onto the component surface using the atomizer (4),
   wherein the atomizer (4) is operated with at least one electrical and/or at least one kinematic operating variable (U, Q₊, Q_-), which comprises a certain high voltage (U) for the electrostatic charging of the coating agent and/or a certain rotational speed of a rotating spray head of the atomizer (4),

   c) dynamically modifying the electrical and/or the kinematic operating variable (U, Q₊, Q_-) of the atomizer (4) during the movement of the atomizer (4),
   characterized

   d) in that the high voltage (U) for the electrostatic charging of the coating agent is generated by means of a high-voltage cascade (9) with several stages of diodes and capacitors,

   e) in that the diodes of the high-voltage cascade are high-voltage-resistant photodiodes which can be controlled by light, and

   f) in that the photodiodes are controlled by the light for modifying the high voltage (U) for the electrostatic charging of the coating agent.
2. The coating method according to Claim 1,
   characterized

   a) in that the atomizer (4) is operated with fluidic operating variables (Q_PAINT, Q_{GUIDE AIR}), wherein the fluidic operating variables reproduce a coating agent flow and/or a guide air flow, and

   b) in that the fluidic operating variables (Q_PAINT, Q_{GUIDE AIR}) of the atomizer (4) are modified dynamically during the movement of the atomizer (4).
3. The coating method according to Claim 1 or 2, characterized by the following steps:

   a) determination of at least one status variable (IL, DL, HS, MA, RB, SB, GF, A, v) of the coating installation, and

   b) dynamic adaptation of the electrical and/or kinematic operating variable and/or of the fluidic operating variables (Q_PAINT, Q_{GUIDE AIR}) of the atomizer (4) during the movement of the atomizer (4) depending on the determined status variable of the coating installation.
4. The coating method according to Claim 3,
   characterized

   a) in that the status variable (HS) of the painting installation indicates whether painting is taking place with or without electrostatic charging of the coating agent, and/or

   b) in that the status variable (IL) of the painting installation indicates whether internal painting or external painting of the components is taking place,

   c) in that the status variable (GF) of the painting installation reproduces the geometry of the component at an impact point of the coating agent,

   d) in that the status variable (A) of the painting installation reproduces the distance between the impact point of the coating agent and an electrical earthing point at which the component is electrically earthed,

   e) in that the status variable (MA) of the painting installation indicates whether the component in question is a plastic component or a component consisting of an electrically conductive material,

   f) in that the status variable (DL) of the painting installation indicates whether detailed painting or surface painting is taking place, and/or

   g) in that the status variable (RB) of the painting installation indicates whether the atomizer (4) is being cleaned or whether the atomizer (4) is applying the coating agent.
5. The coating method according to any one of the preceding claims, characterized by the following steps:

   a) determination of a geometric factor (GF) of the component surface at a paint impact point at which the coating agent impacts the component surface, wherein the geometric factor (GF) reproduces the shape of the component surface at the paint impact point,

   b) adaptation of a desired spray jet width (SB) depending on the geometric factor,

   c) adaptation of at least one of the following operating variables of the atomizer (4) depending on the spray jet width (SB) or geometric factor (GF):

   - paint flow (Q_PAINT),

   - guide air flow (Q_{GUIDE AIR}),

   - painting speed (v) at which the atomizer (4) is moved over the component surface.
6. The coating method according to any one of the preceding claims, characterized by the following steps:

   a) determination of a geometric factor (GF) of the component surface at a paint impact point at which the coating agent impacts the component surface, wherein the geometric factor (GF) reproduces the shape of the component surface at the paint impact point, and

   b) dynamical adaptation of the high voltage (U) for the electrostatic charging of the coating agent depending on the geometric factor (GF), and

   c) dynamical adaptation of a paint flow (Q_PAINT) depending on the geometric factor and/or high voltage, and/or

   d) dynamical adaptation of a guide air flow (Q_{GUIDE AIR}) depending on the geometric factor (GF) and/or high voltage (U).
7. The coating method according to any one of the preceding claims, characterized

   a) in that the electrical and/or the kinematic operating variable and/or the fluidic operating variable (Q_PAINT, Q_{GUIDE AIR}) of the atomizer (4) have a setting time during a change in setpoint value of less than 2s, 1s, 500ms, 300ms, 150ms, 100ms 50ms, 30ms or even less than 10ms, wherein at least 95% of the change in setpoint value is implemented within the setting time, and/or

   b) in that the electrical and/or kinematic operating variables of the atomizer (4) are changed synchronously with the fluidic operating variables (Q_PAINT, Q_{GUIDE AIR}) of the atomizer (4).
8. The coating method according to any one of the preceding claims, characterized in that the high voltage is reduced in a highly dynamic manner by means of a bleeder switch (11) and/or a bleeder resistor (10).
9. The coating method according to any one of the preceding claims, characterized

   a) in that the atomizer (4) is driven by an electric motor in order to allow a high level of rotational speed dynamics, or

   b) in that the atomizer (4) is driven hydraulically or electrically in order to allow a high level of rotational speed dynamics, and/or in that an electrical potential isolation is provided in order to allow electrostatic charging of the coating agent despite the hydraulic or electrical drive.

   c) in that the atomizer (4) is driven pneumatically by a turbine, wherein the turbine can be accelerated and braked by means of compressed air.
10. A coating installation for coating a component surface of a component with a coating agent using an atomizer (4) in a coating installation, in particular for painting a motor vehicle body part with a paint, having

    a) an atomizer (4) for applying the coating agent onto the component surface,

    b) a coating robot for moving the atomizer (4) over the component surface, and

    c) a control unit (4, 12),

    c1) which actuates the atomizer (4) with at least one electrical and/or at least one kinematic operating variable (U, Q₊, Q_-), which comprises a certain high voltage for the electrostatic charging of the coating agent and/or a certain rotational speed of a rotating spray head of the atomizer (4),

    c2) wherein the control unit (4, 12) modifies the electrical and/or the kinematic operating variable (U, Q₊, Q_-) of the atomizer (4) dynamically during the movement of the atomizer (4),

    characterized

    d) in that a high-voltage cascade (9) with several stages of diodes and capacitors is provided for generating the high voltage (U) for the electrostatic charging of the coating agent,

    e) in that the diodes of the high-voltage cascade are high-voltage-resistant photodiodes which are controlled by light, and

    f) in that the photodiodes are controlled by the light for modifying the high voltage (U) for the electrostatic charging of the coating agent.
11. The coating installation according to Claim 10,
    characterized

    a) in that the control unit (4, 12) actuates the atomizer (4) with fluidic operating variables (Q_PAINT, Q_{GUIDE AIR}), wherein the fluidic operating variables (Q_PAINT, Q_{GUIDE AIR}) represent a coating agent flow and/or a guide air flow,

    b) in that the control unit (4, 12) modifies the fluidic operating variables (Q_PAINT, Q_{GUIDE AIR}) of the atomizer (4) dynamically during the movement of the atomizer (4).
12. The coating installation according to any one of Claims 10 to 11, characterized

    a) in that the control unit (4, 12) determines at least one status variable (IL, DL, HS, MA, RB, v, A, GF) of the coating installation,

    b) in that the control unit (4, 12) dynamically adapts the electrical and/or kinematic operating variable and/or the fluidic operating variables (Q_PAINT, Q_{GUIDE AIR}) of the atomizer (4) during the movement of the atomizer (4) depending on the determined status variable (IL, DL, HS, MA, RB, v, A, GF) of the coating installation.
13. The coating installation according to Claim 12,
    characterized

    a) in that the status variable (HS) of the painting installation indicates whether painting is taking place with or without electrostatic charging of the coating agent, and/or

    b) in that the status variable (IL) of the painting installation indicates whether internal painting or external painting of the components is taking place,

    c) in that the status variable (GF) of the painting installation reproduces the geometry of the component at an impact point of the coating agent,

    d) in that the status variable (A) of the painting installation reproduces the distance between the impact point of the coating agent and an electrical earthing point at which the component is electrically earthed,

    e) in that the status variable (MA) of the painting installation indicates whether the component in question is a plastic component or a component consisting of an electrically conductive material,

    f) in that the status variable (DL) of the painting installation indicates whether detailed painting or surface painting is taking place, and/or

    g) in that the status variable (RB) of the painting installation indicates whether the atomizer (4) is being cleaned or whether the atomizer (4) is applying the coating agent.
14. The coating installation according to any one of Claims 10 to 13, characterized

    a) in that the control unit (4, 12) determines a geometric factor (GF) of the component surface at a paint impact point at which the coating agent impacts the component surface, wherein the geometric factor (GF) reproduces the shape of the component surface at the paint impact point,

    b) in that the control unit (4, 12) dynamically adapts a desired spray jet width (SB) depending on the geometric factor (GF),

    c) in that the control unit (4, 12) dynamically adapts at least one of the following operating variables of the atomizer (4) depending on the spray jet width (SB) or geometric factor (GF):

    - paint flow (Q_PAINT),

    - guide air flow (Q_{GUIDE AIR}),

    - painting speed (v) at which the atomizer (4) is moved over the component surface.
15. The coating installation according to any one of Claims 10 to 14, characterized

    a) in that the control unit (4, 12) determines a geometric factor (GF) of the component surface at a paint impact point at which the coating agent impacts the component surface, wherein the geometric factor (GF) reproduces the shape of the component surface at the paint impact point, and

    b) in that the control unit (4, 12) dynamically adapts the high voltage (U) for the electrostatic charging of the coating agent depending on the geometric factor (GF), and

    c) in that the control unit (4, 12) dynamically adapts a paint flow (Q_PAINT) depending on the geometric factor (GF) and/or the high voltage (U), and/or

    d) in that the control unit (4, 12) dynamically adapts a guide air flow (Q_{GUIDE AIR}) depending on the geometric factor (GF) and/or the high voltage (U).
16. The coating installation according to any one of Claims 10 to 15, characterized

    a) in that the electrical and/or the kinematic operating variable and/or the fluidic operating variable (Q_PAINT, Q_{GUIDE AIR}) of the atomizer (4) have a setting time during a change in setpoint value of less than 2s, 1s, 500ms, 300ms, 150ms, 100ms 50ms, 30ms or even less than 10ms, wherein at least 95% of the change in setpoint value is implemented within the setting time, and/or

    b) the coating agent charging is provided with a capacity which is smaller than 2nF.
17. The coating installation according to any one of Claims 10 to 16, characterized by a bleeder switch (11) and/or a bleeder resistor (10) for dynamically reducing the high voltage.
18. The coating installation according to any one of Claims 10 to 17, characterized by

    a) an electric motor for driving the atomizer (4), and/or

    b) a hydraulic drive for the atomizer (4), and/or an electrical potential isolation to allow electrostatic charging of the coating agent despite the hydraulic drive, and/or

    c) a turbine (7) for pneumatically driving the atomizer (4), wherein the turbine (7) can be accelerated and braked by means of compressed air.

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