EP2714288B1 - System for coating, in particular for painting, articles, in particular vehicle bodies - Google Patents

Description

1. a) einer Beschichtungskabine;
2. b) einem Fördersystem, welches die zu beschichtenden Gegenstände durch die Beschichtungskabine führt;
3. c) mindestens einer Applikationseinheit für das Beschichtungsmedium;
4. d) mindestens einem Handhabungsgerät, insbesondere Roboter, das die Applikationseinheit trägt und führt.

The invention relates to a system for coating, in particular painting, of objects, in particular vehicle bodies, with

1. a) a coating booth;
2. b) a conveyor system which guides the articles to be coated through the coating booth;
3. c) at least one application unit for the coating medium;
4. d) at least one handling device, in particular robot, which carries and guides the application unit.

When automatically coating objects, in particular when painting vehicle bodies, not all of the coating medium emerging from the application units reaches the object to be coated. Rather, so-called "overspray" arises, which is discharged to a greater extent with the aid of an air flow from the coating booth and is reflected to a lesser extent on inner surfaces of the coating booth, but preferably on the outer surfaces of the application units and the adjacent areas of the manipulator. These external surfaces must be freed of precipitation at regular intervals.

To facilitate this, is so far common in practice the outer surface of the application unit of the atomizer area up to its mounting location on the handling device, in a painting robot so for example to the wrist, provided with a protective film of, for example Vaseline. This must then be removed manually from time to time and disposed of together with the deposited paint.

It is known in other fields of technology to clean surfaces with the help of CO ₂ . This has the advantage that the cleaned-up areas do not have to be additionally dried, since the CO ₂ used for drying passes directly into the gaseous form by sublimation.

The document FR 2 912 072 described method and apparatus for thermally coating a substrate. A powder sprayer directs a jet of powder at the substrate. At the same time, the powder spray device generates a flame, which heats the substrate. This is undesirable in many cases. Therefore, a nozzle is provided, from which CO ₂ pellets are sprayed onto the substrate. This prevents a rise in temperature.

The publication Motschmann, S., Bilz, M .: "CO2 Rays in Machine and Plant Technology", Electropractor, Vol. 4, 30 April 2010, pages 319-321, Berlin, ISSN: 0013-5569 describes cleaning processes using CO ₂ and mentions a use in paint shops for the pretreatment of plastics prior to painting and bonding.

Object of the present invention is to provide a system of the type mentioned, in which the cleaning of the application unit and adjacent areas with less effort on materials and manual work can be done largely automated.

• e) mindestens ein Reinigungsgerät, das mindestens eine Düse aufweist, aus welcher CO₂ in zu Reinigungszwecken geeigneter Form, inbesondere als CO₂-Schnee oder in der Form von Pellets, austreten und auf die zu reinigenden Flächen der Applikationseinheit und gegebenenfalls benachbarte Bereiche des Handhabungsgeräts aufgebracht werden kann;
• f) einen Tank zur Bevorratung von CO₂ in flüssiger oder fester Form;
• g) eine zentrale Versorgungseinheit, die ihrerseits Fördermittel aufweist, welche in der Lage sind, CO₂ aus dem Tank zu entnehmen und mit einem zur Weiterbeförderung geeigneten Druck bereitzustellen;
• h) eine Sammelleitung, welche mit der Versorgungseinheit verbunden ist und an die mindestens ein Reinigungsgerät angeschlossen ist;

wobei

• i) programmgesteuert eine Relativbewegung zwischen der Düse und der Applikationseinheit herbeigeführt werden kann, derart, dass alle zu reinigenden Flächen der Applikationseinheit von dem aus der Düse austretenden CO₂ erreicht werden können.

This object is achieved in that the system comprises:

• e) at least one cleaning device having at least one nozzle, from which CO ₂ in suitable form for cleaning purposes, in particular as CO ₂ snow or in the form of pellets, and on the surfaces to be cleaned of the application unit and optionally adjacent areas of the handling device can be applied;
• f) a tank for storing CO ₂ in liquid or solid form;
• g) a central supply unit, which in turn Conveying means which are able to remove CO ₂ from the tank and provide with a pressure suitable for further transport;
• h) a manifold, which is connected to the supply unit and to which at least one cleaning device is connected;

in which

• i) programmatically a relative movement between the nozzle and the application unit can be brought about, such that all surfaces of the application unit to be cleaned can be reached by the CO ₂ emerging from the nozzle.

With the present invention, the cleaning of the outer surfaces of the application unit can be fully automated in a similar manner, as has already been possible for the cleaning of the inner flow paths of the application device with solvent. Thus, the total cleaning of the application units in the coating booth can be carried out in a much shorter time without the use of workers; entering the coating booth is generally no longer necessary. The required movements of application unit and / or nozzle are effected in interaction between the central system control and, if necessary, the individual controls associated with the handling devices and / or the cleaning devices.

Compared with the use of protective films, the invention reduces the consumption of chemicals, which at the same time reduces disposal costs. The mission of a protective film is eliminated, which on the one hand the eliminates the production stops caused by this and, on the other hand, no longer exposes the assigned worker to the atmosphere in the coating booth. Cleaning with the help of CO ₂ snow can also take place in sensitive areas where the otherwise used cleaning agent can not be used.

The used for cleaning CO ₂ can come from conventional sources, such as pressure bottles, which are connected to the supply system; Alternatively, the tank of the central supply unit can also be connected directly to a CO ₂ recovery or supply system.

Depending on the shape of the applied to the surfaces to be cleaned CO ₂ , the tank for storage of liquid or solid CO _{2 may be} formed. Solid CO ₂ can already be present in the tank in the form of pellets, which can be transported by means of a corresponding air flow through the manifold.

Alternatively, it is also possible that the solid CO _{2 is} in the form of a block and that a crusher is provided which is capable of rasping small parts from the block. In this embodiment, the loss of CO ₂ by sublimation is smaller than in the storage of pellets.

When liquid CO _{2 is} used, the header preferably comprises a liquid CO _{2 line} and a pressurized air line and is connected to at least one two-component nozzle for producing CO ₂ snow. The CO ₂ snow thus arises only at the exit from the corresponding nozzle.

The nozzle of the cleaning device can be pivotably mounted on a holder, for which purpose a corresponding drive, motor or pneumatic, will generally be provided. In this way, part of the required relative movement between the nozzle and the application unit can take place by movement of the nozzle.

The cleaning device preferably comprises a plurality of nozzles, from which the application unit can be acted upon from different angles. The use of multiple nozzles reduces the amount of relative movement between nozzle and application unit required to clean all surface areas.

It is also expedient if the collecting line is connected to at least one removal point, to which a manual cleaning device can be connected. This manual cleaning device is exceptionally used when the automatic cleaning of the application unit by the cleaning device is not sufficient, or for cleaning other surfaces within the coating booth on which a precipitate has formed.

In an advantageous embodiment of the invention, the cleaning device has an enclosure which has at least one opening through which the application unit can be introduced into the interior of the enclosure. In this way, the cleaning process is largely shielded from the other areas of the coating booth.

Finally, it is useful if the cleaning device has a closed space in which the discharge end of the application unit for flushing the inner Flow paths with solvent can be introduced through an opening. In this way, the cleaning of the outer surface can take place substantially simultaneously with the cleaning of the inner flow paths of the application unit, so that the downtime of the system can be further reduced.

Figur 1

schematisch einen Ausschnitt aus dem Layout einer Lackierkabine;

Figuren 2 bis 5

schematisch im vertikalen bzw. horizontalen Schnitt Reinigungsstationen, wie sie in der Lackierkabine der Figur 1 Verwendung finden können.

Embodiments of the invention will be explained in more detail with reference to the drawing; show it

FIG. 1

schematically a section of the layout of a paint booth;

FIGS. 2 to 5

schematic in vertical or horizontal section cleaning stations, as in the paint booth of the FIG. 1 Can be used.

First, on the FIG. 1 Referenced. This can be read as a schematic layout of a part of a paint booth or as a horizontal section through the spray booth below the ceiling. The paint booth provided overall with the reference numeral 1 comprises two parallel side walls 2, which are closed in the region no longer represented by end faces, which in turn have gates or locks for the objects 4 to be painted in a known manner. The floor of the paint booth 1 is essentially formed by a grate 3, while it is closed at the top, also in a conventional manner, by an air plenum from which air conditioned in the interior of the paint booth 1 can be passed.

The objects to be painted 4, which are shown schematically in the drawing as rectangles and which may be in particular vehicle bodies or parts thereof, are guided by means of a conveyor system 5 in a continuous or intermittent movement through the interior of the painting booth 1, for example in FIG. 1 left to right. The type of conveyor system 5 is irrelevant in the present context.

On both sides of the path of movement of the objects 4 on the conveyor system 5 painting robots 6, 7 are arranged. Again, different designs can be used. For example only, a total of four articulated robot 6 are provided, of which two are arranged on one side of the path of movement of the objects 4, as well as two industrial robots 7, one of which is arranged on one side of the path of movement. Both types of robot have in common that they have a movable robot arm 6a and 7a, at the end of each an application unit 8 and 9 is worn. Each of these application units 8, 9 comprises the actual applicator, which may in particular be spray guns and / or high-rotation atomizers.

Along the side walls 2 of the painting booth 1, a plurality of cleaning stations 10, 11 are provided, which are shown schematically as rectangles. The cleaning stations 10, 11 have in common that they contain at least one nozzle from which CO ₂ can emerge in the form of solid pellets or snow. Details of possible constructions of such cleaning stations 10, 11 are described below with reference to FIGS. 2 to 5 described.

At the in FIG. 1 Upper side wall 2 of the spray booth 1 are provided except the cleaning stations 10, 11 sampling points 12 for connecting manual cleaning equipment, ie cleaning equipment whose nozzles are different from those of the cleaning stations 10, 11 are not performed by robots for certain programs automatically but by hand.

All removal stations 10, 11, 12 are connected via branch lines, which are not provided with the reference numerals for clarity, with a manifold 13.

This leads to a central supply unit 14, which in the embodiment of the FIG. 1 is attached to the lower side wall 2 there from the outside. The central supply unit 14 has a region 14a in which all the units, pumps and valves required for conveying CO ₂ in pellets or in liquid form, as well as associated controls, are accommodated. The provision of auxiliary media, for example compressed air and conveying air, as required for transporting CO _2, in particular in pellet form or for producing CO ₂ snow, also takes place in the region 14 a of the central supply unit 14.

The latter also comprises a tank 14b in which the CO ₂ used for cleaning is kept in the form of pellets or in liquid form. Instead of pellets, it is also possible to use a large solid CO ₂ block, from which smaller solid particles are then shredded as required for transport through lines of suitable size.

The tank 14b is connected via a line 15 with an external source of CO ₂ in connection. This can be a conventional pressure bottle or any other source of CO ₂ . If gaseous CO _{2 is} supplied, of course, the units and devices required for liquefaction or solidification must also be present in the central supply unit 14.

The cleaning stations 10, 11 have an enclosure 16 which has such an opening that the application units 8, 9 can be introduced by the associated robots 6, 7 into the interior of the corresponding cleaning device 10, 11. This generally means an opening upwards and optionally also towards at least one side. Examples of this are described below.

• Der normale Lackiervorgang läuft in üblicher Weise ab:
  • Die zu lackierenden und entsprechend vorbereiteten Gegenstände 4 werden mit Hilfe des Fördersystems 5 in Figur 1 von links kommend zugeführt und geraten dabei in den Bereich der von den Robotern 6, 7 geführten Applikationseinrichtungen 8 bzw. 9. Nach vorgegebenen Bewegungsprogrammen unter dem Kommando der Anlagensteuerung und der individuellen Robotersteuerungen werden die Gegenstände 4 aus den Applikationseinheiten 8, 9 mit Lack besprüht. Wenn sie die Lackierkabine 1 in Figur 1 nach rechts verlassen, sind sie vollständig lackiert oder zumindest ist eine Lackierphase abgeschlossen.

The painting booth 1 described above operates as follows:

• The normal painting process takes place in the usual way:
  • The objects 4 to be painted and prepared accordingly are conveyed by means of the conveyor system 5 in FIG FIG. 1 Coming from the left supplied and fall into the range of guided by the robots 6, 7 application devices 8 and 9. After predetermined movement programs under the command of the system control and the individual robot controls the objects 4 are sprayed from the application units 8, 9 with paint. If you have the paint booth 1 in FIG. 1 left to the right, they are completely painted or at least a painting phase is completed.

• Es sei angenommen, dass der Tank 14b der zentralen Versorgungseinheit 14 über die Leitung 15 mit flüssigem CO₂ gefüllt ist. Der Bereich 14a der zentralen Versorgungseinheit 14 hat die Sammelleitung 13 mit den erforderlichen flüssigen CO₂ und Zerstäubungsdruckluft gefüllt. In diesem Falle umfasst die Sammelleitung 13 getrennte Einzelleitungen, die bis zur jeweiligen Entnahmestelle 10, 11, 12 führen. Flüssiges CO₂ bzw. Zerstäubungsdruckluft steht nunmehr an diesen Entnahmestationen 10, 11, 12 an. Zum Reinigen werden nunmehr die Applikationseinheiten 8, 9 und die diesen benachbarten Bereiche der Roboterarme 6a, 7a durch die oben schon erwähnten Öffnungen hindurch wieder programmgesteuert in die Einhausungen der Reinigungsstationen 10, 11 eingeführt.

The overspray produced during the painting process is essentially taken along by the air flow which flows from the top of the painting booth 1, starting from the above-mentioned air plenum, through the grate 3 forming the bottom of the painting booth 1. Part of the overspray, however, strikes the outside the robot arms 6a, 7a and the application units 8, 9 down. From there they must be removed at certain intervals, depending on the degree of soiling. This happens now in the following way:

• It is assumed that the tank 14b of the central supply unit 14 is filled via line 15 with liquid CO ₂ . The area 14a of the central supply unit 14 has filled the collecting line 13 with the required liquid CO ₂ and atomizing compressed air. In this case, the manifold 13 comprises separate individual lines that lead to the respective removal point 10, 11, 12. Liquid CO ₂ or atomizing compressed air is now at these removal stations 10, 11, 12 at. For cleaning, the application units 8, 9 and the regions of the robot arms 6a, 7a adjacent to them are now again introduced into the housings of the cleaning stations 10, 11 through the openings already mentioned above.

Now, the local valves are opened so that liquid CO ₂ and atomizing compressed air can flow into the corresponding two-component nozzles and form CO ₂ snow there. With this snow, the surface areas of the application units 8, 9 and the adjacent areas of the robot arms 6a, 7a, as far as they are dirty, acted upon. The nozzles, as will be explained in more detail below, can be pivoted again by a program-controlled motor in order to reach all the surfaces to be cleaned. The contamination dissolves, as is known in and of itself by CO ₂ purification process.

The application units 8, 9 are then again with the help of the associated robot arms 6a, 7a from the housings the cleaning stations 10, 11 moved out; remaining, not completely cleaned surfaces can be cleaned with the help of manual cleaning equipment 11a, 12 if necessary.

Then, the painting operation can be resumed immediately without the need for drying or other aftertreatment of the surface areas of application units 8, 9 or adjacent areas of the robot arms 6a, 7a which have been cleaned of paint.

In FIG. 2 schematically a cleaning station 10 is shown in vertical section. A section of the cabin wall 2, a section of the opposite wall of the housing 16, a two-component nozzle 18 fastened to the cabin wall 2 by means of a holder 17 and a two-component nozzle 20 fastened to the housing wall 16 by means of a holder 19 are shown.
The two-component nozzles 18, 20 are supplied via supply hoses 21, 22, which are connected to the manifold 13, with liquid CO ₂ and atomizing compressed air. The two-component nozzles 18, 20 can be pivoted about a horizontal axis 23 or 24 motor or pneumatic under the influence of the system control.

From above is in FIG. 2 between the housing wall 16 and the cabin wall 2, the application unit 8 of a articulated robot 6 introduced. When cleaning the inserted area of the application unit 8 and possibly the adjacent area of the associated robot arm 6a generate the two-component nozzles 18, 20 CO ₂ snow and thus act on the surfaces to be cleaned. In order to reach all the surfaces, the two-component nozzles 18, 20 thereby about the above-mentioned axes 23, 24 pivots. Optionally, additionally the application unit 8 can be rotated about a vertical axis.

After completion of these cleaning operations, the application unit 8 is pulled out of the cleaning station 10 again by means of the associated robot arm 6a.

FIG. 3 shows, also in vertical section, a variant of the cleaning station 10 of FIG. 2 , Corresponding parts are here with the same reference numerals as in FIG. 2 , but marked plus 100. The cabin wall 102 and the housing wall 116 can be seen. In this exemplary embodiment, a bottom wall 125 of the cleaning station 110, in which there is a discharge opening 126, is additionally shown. Above the discharge opening 126, a cleaning box 127 surrounding a substantially closed space is provided, which has an opening 128 which points obliquely upwards and inwards into the cleaning appliance 110 and is surrounded by a seal 129.

At the in FIG. 3 cleaning device 110 shown, a two-component nozzle 120 is provided only on the housing wall 116, which is supplied via the tube 122 with liquid CO ₂ and atomizing air.

For cleaning, the application unit 108 with its foremost end having the actual atomization region 108a is inserted in advance through the opening 128 into the box 127. While the outer surfaces of the application unit 108 are cleaned by means of the two-component nozzle 120 in the manner already described above, the inner flow paths of the application unit 108 is cleaned by solvent which is sprayed via the sputtering area 128a into the interior of the box 127 and finally removed via the drain opening 126. In this way, the outer surfaces are cleaned simultaneously with the inner flow paths of the application unit 108.

Another embodiment of a cleaning device 210 is in horizontal section in FIG. 4 shown. Parts, those of the cleaning device of the FIG. 2 are equal, are provided with the same reference numerals plus 200. To the cabin wall 202, the housing 216 of the cleaning device 210 is attached. This is open at the top and additionally has an opening 230 in one of the side walls. A two-component nozzle 218, 220, 231 is attached to the cabin wall 202 as well as to those side walls of the housing 216 which have no opening. The nozzles 218, 220, 231 in each case enclose an angle of 120 °.

The applicator 208 of a articulated robot is from above and / or through the opening 230 of the housing 216 in the interior in the in FIG. 4 shown position in the middle between the sputtering regions of the two-component nozzles 218, 220, 231 introduced. There, the application unit 208 can be acted upon from three sides with CO ₂ snow. Under favorable circumstances, all surface regions of the application unit 208 can be achieved in this way, without these having to be additionally twisted.

In FIG. 4 is, attached to the cleaning station 211, a removal point 211 a for a self-shown manual cleaning device shown.

FIG. 5 Finally, also in horizontal section, shows a cleaning station 311, the one of FIG. 4 largely corresponds and their parts are provided with reference numerals, which are increased again by 100. The cabin wall 302, the housing 316 and its opening 230 are similar to the corresponding components in the embodiment of FIG. 4 and therefore need not be described again. The main difference between the embodiments of the FIG. 5 and 4 is that in the embodiment of FIG. 5 all three two-component nozzles 318, 320 and 331 are fixed to the cabin wall 302. In this construction, it will generally be necessary to turn the application unit 308 to be cleaned during the cleaning process so that all surface areas of CO ₂ snow are reached.

In the above description of the various embodiments of cleaning devices 10, 11; 110; 211; 311 a cleaning with CO ₂ snow was assumed. The cleaning process, however, essentially takes place in the same way when CO ₂ pellets are used instead of CO ₂ snow. These are guided by means of transport air through the supply line 13 to the various tapping points 10, 11, 12. Their cleaning effect is due to the mechanical impact of the pellets on the surfaces to be cleaned slightly larger in a known manner; cleaning with CO ₂ foam, on the other hand, is gentler.

Claims (15)

1. System for coating articles, with

   a) a coating cubicle;

   b) a conveying system which guides the articles to be coated through the coating cubicle;

   c) at least one application unit for the coating medium;

   d) at least one handling device which carries and guides the application unit;

   characterized in that
   said system comprises:

   e) at least one cleaning device (10, 11) which has at least one nozzle (18, 20; 120; 218, 220, 231; 320, 331) from which CO₂ can emerge in a form suitable for cleaning purposes and can be applied to those surfaces of the application unit (8, 9; 108; 208; 308) which are to be cleaned and optionally to adjacent regions of the handling device (6, 7);

   f) a tank (14b) for storing CO₂ in liquid or solid form;

   g) a central supply unit (14) which, for its part, has conveying means which are capable of removing CO₂ from the tank (14b) and of providing same with a pressure suitable for the further conveying;

   h) a collecting line (13) which is connected to the central supply unit (14) and to which at least one cleaning device (10, 11) is attached;

   wherein

   i) a relative movement between the nozzle (18, 20; 120; 218, 220, 231; 318, 320, 331) and the application unit (8, 9; 108; 208; 308) can be brought about in a programmed-controlled manner such that all of those surfaces of the application unit (8, 9; 108; 208; 308) which are to be cleaned can be reached by the CO₂ emerging from the nozzle (18, 20; 120; 218, 220, 231; 318, 320, 331).
2. System according to Claim 1, characterized in that the tank (14b) of the central supply unit (14) is fillable via a supply line (15) which is connected to pressure cylinders or to a CO₂ recovery or supply system.
3. System according to Claim 1 or 2, characterized in that the tank (14b) is designed for storing liquid CO₂.
4. System according to Claim 1 or 2, characterized in that the tank (14b) is designed for storing solid CO₂.
5. System according to Claim 4, characterized in that the solid CO₂ is present in the form of pellets.
6. System according to Claim 4, characterized in that the solid CO₂ is present in the form of a block, and in that a comminuting device is provided which is capable of chipping small parts from the block.
7. System according to one of Claims 1 to 3, characterized in that the collecting line (13) comprises a line for liquid CO₂ and a line for compressed atomizing air and is connected to at least one two-component nozzle (18, 20; 120; 118, 220, 231; 318, 320, 331) for producing CO₂ snow.
8. System according to one of the preceding claims, characterized in that the nozzle (18, 20; 120; 218, 220, 231; 318, 320, 331) is fastened pivotably to a holder (17, 19; 119; 217, 219, 232; 317, 319, 332).
9. System according to one of the preceding claims, characterized in that the cleaning device (211; 311) has a plurality of nozzles (218, 220, 231; 318, 320, 331) for which the application unit (208; 308) can be acted upon from different angles.
10. System according to one of the preceding claims, characterized in that the collecting line (13) is connected to at least one removal point to which a manual cleaning device (11a, 12; 211a; 311a) can be attached.
11. System according to one of the preceding claims, characterized in that the cleaning device (10; 110; 211; 311) has a housing (16; 116; 216; 316) which has at least one opening (230; 330) through which the application unit (8, 9; 108; 208; 308) can be introduced into the interior of the housing (116; 216; 316).
12. System according to one of the preceding claims, characterized in that the cleaning device (110) has a closed space (127) into which the dispensing end (128a) of the application unit (108) can be introduced through an opening (128) for flushing the inner flow paths with solvent.
13. System according to one of the preceding claims, characterized in that the CO₂ can emerge from the nozzle as CO₂ snow or in the form of pellets.
14. System according to one of the preceding claims, characterized in that the handling device is a robot.
15. System according to one of the preceding claims, characterized in that the system is configured for painting vehicle bodies.

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