EP4132727A1

EP4132727A1 - Coating cabin for coating vehicle wheel rims

Info

Publication number: EP4132727A1
Application number: EP21718065.2A
Authority: EP
Inventors: Peter Steiger; Paulo DOS REIS
Original assignee: Gema Switzerland GmbH
Current assignee: Gema Switzerland GmbH
Priority date: 2020-04-08
Filing date: 2021-04-06
Publication date: 2023-02-15
Also published as: CN115335156A; DE102020109819A1; WO2021204791A1; US20230182160A1

Abstract

The invention relates to a coating cabin (1) for coating vehicle wheel rims, wherein the coating cabin (1) has a coating chamber and a conveying device (6) for transporting the workpieces (2) for coating through the coating chamber. According to the invention, an applicator system is furthermore provided for spraying coating material as required in the coating chamber, wherein the applicator system has a first pistol system (8) for spraying coating material as required onto a first region (11) of the workpieces (2) for coating, a second pistol system (9) for spraying coating material as required onto a second region (12) of the workpieces (2) for coating, and a third pistol system (10) for spraying coating material as required onto a third region (13) of the workpieces (2) for coating.

Description

COATING CABIN FOR COATING VEHICLE RIMS

description

The present invention relates generally to the coating of workpieces and in particular to the coating of rotationally symmetrical workpieces, in particular vehicle rims, with coating material, in particular coating powder.

According to one aspect of the present invention, this relates to a coating booth optimized for coating such workpieces, while according to a further aspect the invention relates to a system for coating such workpieces.

Coating booths for coating workpieces, in particular with coating powder, are generally known from the prior art. Coating booths of this type generally have a coating chamber with a booth floor, two workpiece passages lying opposite one another and a conveying device for transporting workpieces to be coated through the coating chamber. The conveying device is usually arranged below the booth floor of the coating booth and has a workpiece carrier which protrudes through a conveyor slot in the booth floor into the coating chamber of the coating booth. Coating booths with such "floor conveyors" are used in particular for the coating of high-quality workpieces, since a high coating quality can be achieved by arranging the conveyor device below the booth floor Through the coating chamber, dirt particles or powder residues can fall away from the conveyor, which can lead to irregularities in the coating.

From the document DE 103 59 280 A1 a spray coating device is known which is used for spraying the end faces of vehicle rims with coating powder. The device contains a floor conveyor or floor conveyor with motorized rotatable spindles arranged one behind the other, on whose upper receiving surface one of the vehicle rims is located. The system comprises four spraying stations, with two spray guns being arranged diametrically over a rim in a stationary and non-rotatable manner at each of the spraying stations. The spray pistols are directed vertically downwards in order to spray coating powder onto the end face of the vehicle rim located underneath, while the spindle with the vehicle rim rotates around the vertical axis of rotation at the spraying station. To coat the back of the rim, two additional, upwardly directed stationary spray guns are provided.

In one embodiment, the floor conveyor runs intermittently, i.e. it stops while the rim is being coated. This has the disadvantage that the floor conveyor has to be stopped every time a vehicle rim is to be coated. After the vehicle rim has been coated, the floor conveyor must first start again and then stop again as soon as the next vehicle rim has reached the coating station.

In another embodiment, the floor conveyor is moved continuously past the stationary spray guns, even while the vehicle rims are being coated. In order to be able to coat the vehicle rims with sufficient coating powder, the floor conveyor must travel extremely slowly.

Both embodiments have the disadvantage that the number of vehicle rims that can be coated per unit of time is relatively limited. This can be counteracted by using a large number of spray stations. this has but the disadvantage that the installation space for the entire coating system is relatively large.

The present invention is based on the object of specifying a coating cabin and a system for coating, in particular, rotationally symmetrical workpieces, in particular vehicle rims, with coating material, in particular coating powder, wherein the coating booth or the coating system can be used as flexibly and automatically as possible and yet delivers optimum productivity and economy.

With regard to the coating booth, this object is achieved by the subject matter of independent claim 1, with advantageous developments of the coating booth according to the invention being specified in the corresponding dependent claims.

With regard to the coating system, the object on which the invention is based is achieved by the subject matter of the independent claim 17, with advantageous developments of the coating system according to the invention being specified in the corresponding dependent claims.

Accordingly, the invention relates in particular to a coating booth for coating particularly rotationally symmetrical workpieces, in particular vehicle rims, with coating material, in particular coating powder, the coating booth having a coating chamber and a conveyor device for transporting the workpieces to be coated through the coating chamber. The coating chamber of the coating booth according to the invention has a booth floor, two opposite side walls each with a workpiece passage, two opposite side walls and adjacent to the side walls with the workpiece passages and a cabin roof opposite the booth floor. The conveyor, which is used to transport the workpieces to be coated through the coating chamber, is arranged below the Kabinenbo dens and has a workpiece carrier which protrudes through a För derschlitz in the cabin floor into the coating chamber of the coating cabin. In the coating booth according to the invention, an applicator system is also used for spraying coating material in the coating booth as required. The applicator system has a first gun system for spraying coating material as required onto a first area of the workpieces to be coated, a second gun system for spraying coating material as required onto a second area of the workpieces to be coated and a third gun system for spraying coating material onto a third as required Area of the workpieces to be coated.

The first gun system of the applicator system is particularly designed to spray coating material, if necessary, onto a visible area of the workpieces to be coated. The term "visible area" used herein is to be understood as the so-called A-side of the workpiece when the workpiece is used as intended third area is the side of the vehicle rim opposite the visible side.

The second gun system of the applicator system is designed to spray coating material as required onto a side area of the workpieces to be coated that is adjacent to the visible area. The third pistol system, on the other hand, is designed for spraying coating material as required onto a rear-side area of the workpieces to be coated opposite the visible area.

In the coating booth according to the invention it is provided in particular that the first gun system is assigned a first axis or positioning system for positioning and / or aligning the first gun system relative to the workpieces to be coated during a coating process. The second gun system is assigned a second axis system for positioning and / or aligning the second gun system relative to the workpieces to be coated during a coating process, while the third gun system is assigned a third axis system for positioning and / or aligning the third gun system relative to the workpieces to be coated. According to preferred implementations of the coating booth according to the invention, the first, second and third axis or positioning systems are each implemented as a system that runs along with the workpieces to be coated when the workpieces to be coated are transported through the coating chamber. Each axis or positioning system is movable relative to the coating chamber along the side walls adjoining the side walls with the workpiece passages, the axes or positioning systems being designed in such a way that they are synchronized or asynchronous with a conveyor speed of the conveyor device move.

In particular, it is provided that the second and third axis systems are each connected to the correspondingly assigned gun system via an opening formed in a side wall adjoining the side walls with the workpiece passages, with the second and third axis system preferably being connected to the side walls via the same opening are connected with the workpiece passages adjacent side wall with the correspondingly assigned Pis tole system.

According to preferred embodiments of the present invention it is provided that only the first gun system executes a movement that is asynchronous to the running conveyor device, while the second and third gun system move synchronously with the conveyor movement.

The first, second and third axis systems each preferably have a pistol system or a plurality of pistol systems and preferably two pistol systems each. In this way, a higher throughput of workpieces to be coated is achieved because several workpieces can always be coated at the same time.

Advantageously, the second and third axis systems have a common transport device for moving the second and third gun systems together relative to the coating chamber and synchronously with the workpieces transported through the coating chamber and to be coated with the aid of the conveyor device. In contrast, the first axis or positioning system should have a transport device that is independent of the second and third axis system, which is used to move the first gun system relative to the coating chamber and asynchronously to the workpieces to be coated and in particular transported through the coating chamber with the aid of the conveyor device be designed independently of the common transport device of the second and third axis system.

According to preferred implementations of the coating booth according to the invention, it is provided that a robot arm system is assigned to the first axis system, which with the help of a robot guide above the conveyor device and in particular above the workpieces to be coated and preferably on the booth roof together with the first gun system relative to the coating chamber and in particular asynchronously can be moved with a transport movement of the workpieces to be coated.

While a robot arm system is preferably assigned to the first axis or positioning system, a linear positioning system is assigned to the second and third axis systems, in particular for independent positioning and / or alignment of the second and third gun systems relative to the workpieces to be coated.

Preferably, the first axis or positioning system is assigned a control device which is designed to control the first axis system and in particular a robot arm system assigned to the first axis system such that the coating guns of the first gun system each have a predetermined and / or have a definable position and / or orientation relative to the workpieces to be coated, this previously fixed and / or definable position and / or orientation depending in particular on the type and / or size of the workpieces to be coated.

The first gun system preferably has at least one first coating gun and at least one further, second coating gun, the at least one first coating gun being movable and / or orientable relative to the workpieces to be coated independently of the at least one further, second coating gun . The first gun system preferably has at least two further coating guns, the at least two further coating guns can be moved and / or aligned independently of one another relative to the workpieces to be coated.

Similarly, it is advisable for the second gun system to have at least one first coating gun and at least one further, second coating gun, with the at least one first coating gun preferably independent of the at least one further, second coating gun relative to the workpieces to be coated is movable and / or alignable. As an alternative or in addition to this, it can be provided that the third gun system has at least one first coating gun and the at least one further, second coating gun, the at least one first coating gun preferably being independent of the at least one further, second coating gun relative to the workpieces to be coated is movable and / or alignable.

The coating guns are preferably electrostatic coating guns which are designed to electrostatically charge the coating material to be sprayed with the coating gun. According to preferred implementations of the coating booth according to the invention, it is provided that the coating guns are assigned a control device for controlling and / or regulating the current strengths for charging the coating material. The control device should in particular be designed to regulate current values below 10 pA in at least 0.5 pA steps.

With regard to the coating booth, it is advantageously provided that at least partial areas of the booth floor which surround the conveyor slot are designed in the form of a ramp, with at least one air blowing device being provided for preferably pulsed blowing out of an air stream along the ramped partial area of the booth floor in the direction of at least one suction channel provided in the booth floor. The at least one air blowing device is advantageously provided on the conveyor slot.

At least one further air-blowing device is preferably used on or in at least one side wall of the coating booth which adjoins the side walls with the workpiece passages. The one more air injection direction is in particular designed to blow out an air stream, preferably pulsed ent long of the cabin floor in the direction of the at least one suction channel provided in the cabin floor.

The system according to the invention for coating, in particular, rotationally symmetrical workpieces, in particular vehicle rims, with coating material, in particular coating powder, has a coating booth of the aforementioned type according to the invention and a coating material supply for supplying coating material to the gun systems of the applicator system. The coating material supply is designed in particular to supply the first gun system exclusively with fresh coating material, and to supply fresh coating material with recovery material or only recovery material to the second and third gun systems.

The term "recovery material" used herein is to be understood as coating material which has already been sprayed at least once during a coating process and is accordingly recycled. Such recovery material is sometimes also referred to as "overspray" material.

According to developments of the coating system according to the invention, it is provided that the coating material supply preferably has at least one coating material pump for each gun system, the coating material pump preferably being based on the dense flow principle and being designed for continuous coating material delivery.

An exemplary embodiment of the coating booth according to the invention is described in greater detail below with reference to the accompanying drawings.

Show it:

FIG. 1 schematically and in a partially sectioned view, an exemplary embodiment of the coating booth according to the invention; FIG. 2 schematically shows a sectional view through a workpiece (here

Vehicle rim) with the different areas assigned to the pistol systems of the coating booth according to the invention;

FIG. 3a schematically shows an exemplary positioning of the coating guns of the first gun system for two workpieces to be coated at the same time;

FIG. 3b schematically shows the arrangement of the coating guns of the first gun system during a coating process for other, smaller workpieces;

FIG. 4a schematically shows the arrangement of the coating guns of the third gun system of the coating booth according to the invention during a coating process for two workpieces; and

FIG. 4b schematically shows the alignment and arrangement of the coating guns of the third gun system during a coating process for other, smaller workpieces.

The invention is described in more detail below in connection with a coating booth 1 for powder coating vehicle rims 2.

The original equipment manufacturers of light alloy wheels (vehicle rims 2) nowadays rely largely on powder-coated surface coating in industrial production. The main advantages, such as impact resistance, scratch resistance, high corrosion protection and easy maintenance, outweigh this. In the powder coating process, in addition to the thorough pretreatment of the parts and the controlled baking of the powder coating, the powder application, ie the application of the coating powder to the metal surface, determines quality, flexibility and productivity. The electrostatic chargeability of the coating guns used as spray devices on the one hand and a cabin system tailored to the rim coating on the other hand play a key role. ok

On the other hand, the manufacturers of vehicle rims are facing ever higher demands due to increasing customization, a variety of colors and rim types, a wide variety of sizes and increased quality requirements.

The coating booth 1 according to the invention, which is described in more detail below with reference to the drawings using a Ausführungsbei game, meets these requirements and in particular enables flexible and automated coating with optimum productivity and economy.

The exemplary embodiment of the coating booth 1 according to the invention, which is shown schematically and in a partially sectioned view in FIG. 1 essentially has a coating chamber which in turn has a booth floor 3, two opposing side walls each with a workpiece passage (not shown in FIG. 1), two opposing side walls 4 adjoining the side walls with the workpiece passages and a car roof 5 opposite to the car floor 3 has.

In addition, a conveyor 6 is used to transport the workpieces to be coated (here vehicle rims 2). The Fördervorrich device 6 is arranged below the booth floor 3 and has a workpiece carrier (spindle 7) which protrudes into the coating chamber of the coating booth 1 via a conveyor slot in the booth floor 3.

At least partial areas 18 of the cabin floor 3, which ben the conveyor slot vice versa, are designed in a ramp-shaped manner. Air blowing devices are provided for the preferably pulsed blowing out of an air stream along the ramp-shaped partial area 18 of the cabin floor 3 in the direction of suction channels 19 provided in the cabin floor 3.

In addition, further air blowing devices are preferably provided, which are provided on or in at least one side wall 4 of the coating booth 1, which is adjacent to the side walls with the workpiece passages.

This at least one further air blowing device is designed to blow out an air stream, preferably pulsed, along the cabin floor 3 in the direction of the minimum one suction channel 19 provided in the cabin floor 3. The coating booth 1 according to the invention, as shown using the example in FIG. 1 also has an applicator system for spraying coating material in the coating booth 1 as required.

In particular, it is provided in this context that the applicator system has a first gun system 8 with a plurality of coating guns, a second gun system 9 with a plurality of coating guns and a third gun system 10 with a plurality of coating guns. The coating guns of the first gun system 8 are provided for spraying coating material onto a first area 11 of the workpieces to be coated (vehicle rims 2) if necessary, while the coating guns of the second gun system 9 are used for spraying coating material onto a second area 12 of the serve to be coated workpieces, and while the coating guns of the third gun system 10 are used to spray coating material on a third area 13 of the workpieces to be coated if necessary.

The corresponding areas 11, 12, 13 of the workpiece 2 which are assigned to the guns of the first, second and third gun systems 8, 9, 10 are shown in FIG. 2 shown.

Accordingly, the guns of the first gun system 8 are used in particular to spray coating material onto a visible area of the workpieces 2 to be coated, the guns of the second gun system 9 serving, if necessary, to apply the coating material to a side area (rim base) adjoining the visible area to be coated workpieces 2, while the guns of the third gun system 10 are used to spray coating material, if necessary, onto a rear area of the workpieces 2 to be coated opposite the visible area.

To position and / or align the pistols of the first pistol system 8, a first positioning or axis system 14, which is assigned to the first pistol system 8, is used. In the same way, the second and third gun systems 9, 10 are each assigned a second and third axis system 15, 16 for positioning and / or aligning the guns of the second and third third gun system 9, 10 relative to the workpieces 2 to be coated during a coating process.

As in FIG. 1, the second and third axis systems 15, 16 are each connected to the coating guns of the correspondingly assigned gun systems 9, 10 via an opening 17 formed in a side wall 4 of the coating booth 1.

In particular, the second and third axis systems 15, 16 have a common transport device for jointly moving the second and third gun systems 9, 10 relative to the coating chamber and synchronously with the workpieces 2 to be coated, which are transported through the coating chamber with the aid of the conveyor device 6 .

The first axis system 14 has in the case of FIG. The embodiment of the coating booth 1 according to the invention shown in FIG. 1 has a transport device independent of the second and third axis systems 15, 16, which is used to move the first gun system 8 relative to the coating chamber and asynchronously to the ones to be coated with the aid of the conveyor 6 through the coating chamber Workpieces 2 is formed.

As with the second and third axis systems 15, 16, the first axis or positioning system 14 is assigned a linear positioning system for positioning and aligning the coating guns of the first gun system 8.

As an alternative to this, however, it would also be conceivable that a robot arm system for positioning and aligning the coating guns of the first gun system 8 is assigned to the first axis or positioning system 14.

As in FIG. 3a, b and FIG. 4a, b, the first and third gun systems 8, 10 each have at least one first coating gun and at least one further, second coating gun, the at least one first coating gun being independent of the at least one further, second coating gun of the corresponding gun system 8, 10 can be moved and / or aligned relative to the workpieces 2 to be coated. In particular, it is provided that the first axis system 14 can be controlled with the aid of a suitable control device in such a way that the at least one first coating gun and the at least one further, second coating gun each have a previously defined and / or definable position and / or orientation has the workpieces 2 to be coated, the previously determined and / or determinable position and / or orientation depending in particular on the type and in particular on the size of the workpieces 2 to be coated. The same applies in a figurative sense to the coating guns of the third gun system 10.

In the coating booth 1 according to the invention, which is used in particular for powder coating of vehicle rims 2, the rim axis is aligned vertically during the powder application, i.e. the vehicle rim is transported through the coating booth 1 in this position by means of a floor conveyor 6 on rotatable spindles 7.

This fact indicates that the coating booth 1 has been specially developed for coating rims. In the case of a cabin concept, the focus is on the air routing within cabin 1, the possibilities of the axis systems 14, 15, 16 and their integration and, last but not least, the question of throughput.

In general, a coating booth 1 manages with three openings, two of which are used as entry and exit openings for the vehicle rims 2 passing through. Ideally, these openings are also intended as access to the cabin for maintenance matters.

The lateral third booth opening 17 is the actual coating access of the individual guns of the second and third gun systems 9, 10, which are mounted on an axle system 14, 15, 16, to the vehicle rim 2.

In addition to these physical requirements, the openings 17 also meet the requirements of the air flow through the coating booth 1 . The resulting air currents prevent powder from escaping from booth 1. The air flowing in is allowed to continue the coating process do not hinder. The side cabin opening 17 is correspondingly large for axially moving systems 14, 15, 16 or when using robots.

On the other hand, the requirement for uniform and calm air flows in the area of the active powder application on the vehicle rim 2 is decisive for the coating result. The vehicle rim 2 is preferably coated over approximately 75% of the total length of the cabin by the coating guns running along with it. Changes in flow conditions are to be expected, particularly at the cabin entrances and exits.

The floor conveyor 6, which runs through the coating booth 1, is separated from the interior of the coating booth 1 by a housing 18 which can be removed for maintenance purposes. The spindle leadthrough itself is also sealed in order to avoid coating powder falling onto the floor conveyor 6.

The housing 18 and the floor 3 of the coating booth 1 are cleaned automatically and clocked by several air blower strips from the coating powder, which is fed back into the powder cycle as return powder. The air blow bars expel air along the floor surfaces in a pulsed manner, pushing the excess powder to the suction slot or suction channel 19. This procedure is on the one hand more effective and on the other hand it saves energy costs compared to a permanently active blow-off system.

In the coating booth 1 according to the invention, the workpieces (vehicle rims 2) are coated with powder relative to the floor conveyor movement. In this way, a higher throughput is achieved from the outset than with stop-and-go operation.

During the coating process, an axis system moves all coating guns relative to the floor conveyor movement (i.e. movement of the vehicle rims 2). The rim 2 itself is in rotation around its own axis. With the coating time of a vehicle rim 2 and the planned throughput per hour, the necessary conveying speed and also the length of the cabin 1 can be determined.

In the case of a planned future increase in throughput, the maximum conveying speed can be determined in a first step using the same approach, which allows a certain cabin length. An alternative and more efficient is to install a second gun set on the existing axis system. Thus, two vehicle rims 2 are coated at the same time, which in principle corresponds to doubling the throughput while maintaining the cabin 1. The advantage of this application is that the individual coating parameters, such as floor conveyor speed, rim rotation, powder output, floch voltage and current for coating powder charging and coating programs, can continue to be used and thus empirical values can continue to be used.

Viewed from the outside, a powder cloud following the vehicle rim 2 to be coated is formed during the coating process. The powder-spraying pistols move relative to the conveying direction of the vehicle rim 2, which means a powder cloud standing relative to the vehicle rim 2. The three rim areas 11, 12, 13 according to FIG. 2 (visible surface with holes, inner surface and rim well) each assigned a gun group 8, 9, 10.

Each of these groups 8, 9, 10 coated with individual coating parameters. The distances to the vehicle rim 2, the orientations of the gun and their number depend on the rim type (design, size and coating requirements or powder type).

Ideally, a coating system knows the type of rim to be coated and is able to automatically call up the necessary system settings using stored programs. The electrostatic coating parameters are stored in the system control as programs according to the type of wheel or rim.

Ideally, a complex axis system is available for positioning the individual pistols or groups of pistols 8, 9, 10. This means that every type of wheel or rim can be coated with the ideal gun positions and number of guns. For example, when coating small workpieces, coating guns that are not required can be parked outside the event (see FIG. 3b and FIG. 4b).

For the highest quality optics, especially the visible surfaces of the workpieces 2, the currents for powder charging should be in the low range (less than 10 mA) be precisely adjustable in order to bring the properties of the coating powder to gel. In addition, the deliberate dissipation of superfluous free ions optimizes the regularity of the coating, ie influenza charges in the powder are prevented and the formation of orange peel is intercepted.

In particular, only a certain amount of charge is required and each type of powder can tolerate a different ideal amount in order to achieve the best possible coating quality. Overloading the coating powder lowers the application efficiency and tends to cause surface defects. The reasons for this are too high field line concentrations or too high an ion flow per unit of time and area. Back-ionization takes place in easily accessible areas (orange peel effect from back-spraying), while in areas that are more shielded off, the result is a powder layer that is too thin.

Overloading the powder should be avoided, as otherwise the potential of the coating powder not only remains unused, but may even be destroyed. In order to do justice to the properties, precise regulation of the current values below 10 pA is necessary in order to have a controlled influence on the degree of charge of the powder and thus to increase the optical surface quality. A regulation in 0.5 pA steps is particularly advantageous.

Working with small charging currents also has the effect that the powder can be deposited better in depressions, which has a positive effect on rim holes or spaces between spokes.

So-called injectors based on the Venturi principle can be used to convey powder from a storage container to the coating guns. With this technology, however, the delivery stability is heavily dependent on the condition of the inner, powder-contacting components of the injector, wel che are considered wear parts. At the high physically determined speeds, coating powder has an abrasive effect, which ultimately means that the delivery rate deviates over a short period of time and, as a result, the parts concerned need to be replaced (maintenance stop).

In order to avoid this, pumps are preferably used to convey powder. This conveyor technology has no such wear behavior. The powder delivery rate remains stable and does not change over a long period of time. In order to deliver the powder output quantity required for a coating, the above-mentioned quantity fluctuations must be taken into account in the case of an injector. This means that the real output is higher than the target value during the entire time. This is not only problematic with regard to reproducible layer thicknesses, but also creates unnecessary waste of powder.

The properties of a coating powder are best preserved during conveyance if the coating powder can "flow" as freely and homogeneously as possible without physical influences. Abrupt changes of direction, accelerations, excessive speeds or tight bending radii are all influences that change the properties of a coating powder The coating powder must arrive at the atomizer of the coating gun in its original state as far as possible for optimal charging, correct cloud formation and finally generation of the required powder layer.

For this reason, powder pumps that are mounted directly on the powder container are preferably used, so that an extremely short and rigid suction path is implemented. Once at the powder pump, an absolutely straight and step-free powder channel inside the pump ensures gentle powder transport, which is particularly beneficial for sensitive powder types such as metallic or structured powder.

The atomizing air is added directly to the coating gun and is thus completely separated from the powder transport. This enables an ideal formation of the powder cloud in terms of shape and speed and at the same time prevents a pulsating powder cloud and thus an uneven powder charge, which leads to irregularities in the coating.

Preferably, at least two powder circuits are provided, the powder supply of a first gun group only with fresh powder and a wider gun group thus a fresh / return powder mix.

Claims

1. Coating booth (1) for coating, in particular, rotationally symmetrical workpieces (2) (2), in particular vehicle rims, with coating material, in particular coating powder, the coating booth (1) having the following: a coating chamber, which has a booth floor (3), two opposite one another Has side walls each with a workpiece passage, two side walls (4) lying opposite one another and adjoining the side walls with the workpiece passages and a car roof (5) opposite the car floor (3); a conveying device (6) for transporting the workpieces (2) to be coated through the coating chamber, the conveying device (6) being arranged below the booth floor (3) and having a workpiece carrier (7) which via a conveying slot in the booth floor (3) in the coating chamber of the coating booth (1) protrudes; and an applicator system for spraying coating material as required in the coating chamber, the applicator system having a first gun system (8) for spraying coating material as required onto a first area (11) the workpieces (2) to be coated, a second gun system (9) for spraying coating material as required onto a second area (12) of the workpieces (2) to be coated and a third gun system (10) for spraying coating material onto a third area ( 13) of the workpieces (2) to be coated.

2. Coating booth (1) according to claim 1, wherein the first gun system (8) is designed for spraying coating material as required onto a visible area of the workpieces (2) to be coated, the second gun system (9) being designed for spraying coating material as required on a side area of the workpieces (2) to be coated adjoining the visible area, and the third gun system (10) being designed for spraying coating material as required onto a rear area of the workpieces (2) to be coated opposite the visible area.

3. Coating booth (1) according to claim 1 or 2, wherein the first gun system (8) is assigned a first axis system (14) for positioning and / or aligning the first gun system (8) relative to the workpieces (2) to be coated during a Coating process, with the second gun system (9) being assigned a second axis system (15) for positioning and / or aligning the second gun system (9) relative to the workpieces (2) to be coated during a coating process, and with the third gun system (10) a third axis system (16) is assigned for positioning and / or aligning the third gun system relative to the workpieces (2) to be coated during a coating process.

4. Coating booth (1) according to claim 3, wherein the first, second and third axis system (14, 15, 16) each as one with the workpieces (2) to be coated during a transport of the workpieces (2) through the coating chamber System are implemented, each axis system (14, 15, 16) relative to the coating chamber along the side walls is movable with the side walls (4) adjoining the workpiece passages, the axis systems (14, 15, 16) being designed such that they move synchronously with a conveying speed of the conveying device (6).

5. Coating booth (1) according to claim 3 or 4, wherein the second and third axis system (15, 16) each via an opening (17) formed in a side wall (4) adjoining the side walls with the workpiece passages with the correspondingly assigned gun system ( 9, 10), the second and third axis systems (15, 16) preferably being connected to the correspondingly assigned gun system (9, 10) via the same opening (17) in a side wall (4) adjoining the side wall with the workpiece passages .

6. Coating booth (1) according to one of claims 3 to 5, wherein the second and third axis system have a common transport device for jointly moving the second and third gun system relative to the coating chamber and synchronously with the aid of the conveyor device (6) through the Coating chamber transported workpieces to be coated (2).

7. Coating booth (1) according to one of claims 3 to 6, wherein the first axis system (14) has a transport device which is independent of the second and third axis systems (15, 16) and which is used to move the first gun system (8) relative to the coating chamber and in particular is designed asynchronously to the workpieces (2) to be coated and transported through the coating chamber with the aid of the conveying device (6) and in particular independently of the common transport device of the second and third axis systems (15, 16).

8. Coating booth (1) according to one of claims 3 to 7, wherein the first axis system (14) is assigned a robot arm system, which with the help of a robot guide above the conveyor device (6) and in particular above the workpieces to be coated (2) together with the first gun system (8) relative to the Coating chamber and, in particular, can be moved relative to the workpieces (2) to be coated.

9. Coating booth (1) according to one of claims 3 to 8, wherein the second and third axis systems (15, 16) are each assigned a linear positioning system for, in particular, independent positioning and / or alignment of the second and third gun system relative to the workpieces to be coated (2).

10. Coating booth (1) according to one of claims 3 to 9, wherein the first gun system (8) has at least one first coating gun and at least one further, second coating gun, and wherein the first axis system (14) is assigned a control device which is designed to control the first axis system (14) in such a way that the at least one first coating gun and the at least one further, second coating gun each have a previously defined and / or definable position and / or orientation relative to the workpieces (2) to be coated, the predefined and / or definable position and / or orientation depends in particular on the type and / or size of the workpieces (2) to be coated.

11. Coating booth (1) according to one of claims 3 to 10, wherein the first, second and third axis system (14, 15, 16) are formed such that only the first gun system (8) executes an asynchronous movement to the running conveyor , while the second and third gun systems (9, 10) move synchronously with the conveyor movement.

12. Coating booth (1) according to one of claims 1 to 11, wherein the first gun system (8) has at least one first coating gun and at least one further, second coating gun, wherein the at least one first coating gun is relatively independent of the at least one further, second coating gun can be moved and / or aligned with respect to the workpieces (2) to be coated.

13. Coating booth (1) according to claim 12, wherein the first gun system (8) has at least two further coating guns, wherein the at least two further coating guns can be moved and / or aligned independently of one another relative to the workpieces (2) to be coated.

14. Coating booth (1) according to one of claims 1 to 13, wherein the second gun system (9) has at least one first coating gun and at least one further, second coating gun, wherein preferably the at least one first coating gun is independent of the at least one further, second The coating gun can be moved and / or aligned relative to the workpieces (2) to be coated; and / or wherein the third gun system (10) has at least one first coating gun and at least one further, second coating gun, the at least one first coating gun preferably being movable and independent of the at least one further, second coating gun relative to the workpieces (2) to be coated / or is alignable.

15. Coating booth (1) according to one of claims 11 to 14, wherein the coating gun is an electrostatic coating gun which is designed to electrostatically charge the coating material to be sprayed with the coating gun, the coating gun being assigned a control device for controlling and / or regulating the Amperages for charging the coating material.

16. Coating booth (1) according to one of claims 1 to 15, wherein at least partial areas (18) of the booth floor (3), which surround the conveyor slot, are ramp-shaped, with at least one air blowing device being provided for preferably pulsed blowing out of an air stream along the ramp formed partial area (18) of the cabin floor (3) in the direction of at least one suction channel (19) provided in the cabin floor (3).

17. Coating booth (1) according to claim 16, wherein the at least one air blowing device is provided on the conveyor slot, and wherein at least one further air blowing device is provided on or in at least one side wall (4) of the coating booth (1), which is adjacent to the side walls with the workpiece passages, which is formed, preferably an air flow to blow out pulsed along the cabin floor (3) in the direction of the at least one suction channel (19) provided in the cabin floor (3).

18. A system for coating, in particular, rotationally symmetrical workpieces (2), in particular vehicle rims, with coating material, in particular coating powder, the system comprising: a coating booth (1) according to one of claims 1 to 17; and a coating material supply for supplying coating material to the gun systems (8, 9, 10), the coating material supply being designed to supply the first gun system (8) exclusively with fresh coating material and to supply the second and third gun systems (9, 10) with fresh coating material with recovery To supply material or only recovery material.

19. System according to claim 18, wherein the coating material supply preferably has at least one coating material pump for each gun system (8, 9, 10), the coating material pump being based on the dense flow principle and being designed for continuous coating material delivery.

20. System according to claim 19, wherein the coating material pump is a dense phase pump with at least one delivery chamber, the at least one delivery chamber being provided in an absolutely straight and step-free powder channel of the coating material pump.