EP0745001B1 - Painting process and spray painting device suitable for implementing the process - Google Patents

Abstract

PCT No. PCT/EP95/00351 Sec. 371 Date Aug. 13, 1996 Sec. 102(e) Date Aug. 13, 1996 PCT Filed Feb. 1, 1995 PCT Pub. No. WO95/22410 PCT Pub. Date Aug. 24, 1995A paint curtain device is proposed in which object (13) to be painted are moved through a paint curtain (5) consisting of liquid paint. In order to make possible the optimal orientation of the objects (13) to be painted, while passing through the paint curtain (5) they are continuously fixed in place on holding means (25) of a conveying system (12) which crosses through the paint curtain (5) when passing through the area of a lateral edge (16). Furthermore, a method for painting objects (13) is proposed for whose execution the paint curtain device is suited.

Description

The invention relates to a method for serial painting of visible body parts made of metal of motor vehicles before assembly on the motor vehicle, with an object surface to be painted in a Expansion direction is curved.

Most of the body parts of cars after assembly remain visible before installation for the first time corrosion protection and painted for visual reasons. As an example of such a visible body part is the one found in several vehicle types, on the B-pillar attached panel to name, which is made of metal and one the highest quality paint required. The aperture is regularly in the longitudinal direction of expansion at least according to the later body shape slightly arched.

As a reliable painting process for such objects So-called paint spraying has proven itself so far. In spite of the existing curvature of the object surface to be painted, a satisfactory painting result is achieved here. However, they are with such a painting process previously associated costs are still relatively high. A a large part of the sprayed paint does not apply to that lacquered object surface and goes through the exhaust air lost. A recovery for recycling is so far not possible with reasonable costs. It also requires more expense Protection and filter systems to prevent that air enriched with solvent to an unacceptable degree got into the atmosphere.

The present invention is therefore based on the object propose a procedure of the type mentioned at the outset that a cheaper painting of the without sacrificing quality Allows objects.

To solve the problem is according to the characterizing part of the Claim 1 provided that the objects to be painted arranged on holding means outside the paint curtain Defines the transport device and then under permanently remaining on the respectively assigned holding means with a falling paint curtain made of liquid paint moved transversely to the curtain level such that the curved object surface faces upwards and the Direction of expansion of the curvature, seen in plan view, with the direction of transport coincides with the one to be painted Objects passing through the paint curtain from one lying outside the paint curtain and at least one the area assigned to the side edges of the paint curtain in the paint curtain and through controlled positioning the holding means that when passing through the paint curtain present alignment of the objects to be painted influenced.

One therefore uses known measures of the so-called Paint casting process back, which was previously mainly in the Furniture industry is used. However, it is envisaged the objects to be painted on holding means of a transport device to be determined and under constant leave to pass these holding devices through the paint curtain. The objects to be painted are thus throughout Paint job kept optimal and can even with Required by suitable changes in position of the holding means in each case be aligned so that the paint application in relation to The paint distribution and layer thickness are optimal. It has shown that in this way high quality paint layers can be generated that give a glass-like impression and both optically and in terms of corrosion protection meet the highest requirements. Since no paint atomization takes place, the unnecessary paint of the paint curtain caught easily and without much effort Recycling. Since there is hardly any air pollution takes place, is the effort for protection and Filtering measures low, so that the process as a whole proves to be extremely inexpensive.

US-A-3,984,902 does (cf. preamble of claim 1) a method already emerges with the arched objects, here: front letter from Cathode ray tubes, can be coated. It runs the transport device carrying the objects, however through the paint curtain, so that despite Protect existing protective devices may cause inaccuracies in the transportation of the items and thus lead to a loss of quality in the coating can.

Paint pouring devices as such are known. One of the notifiers known type has a casting head for production one consisting of liquid paint flowing downwards Paint curtain, over a distance below the Pouring head arranged collecting device for unused Paint the paint curtain, and over an outside of the Falling paint curtain arranged area Transport device for transporting the paint to be painted Objects on a paint curtain across the curtain level crossing transport route.

The main problem with this known device is that objects whose surface to be painted are uneven and especially curved, is very difficult to paint let and the quality of the painting result above all requirements in automotive engineering are not sufficient. This applies in particular to objects with small dimensions. This is mainly due to the fact that the paint to be painted No objects when passing through the paint curtain can be guided exactly because they have a gap need to cross, which is between two the transport facility forming conveyor belts and the passage of the paint curtain to the fall arrester.

Another object of the invention is therefore a Paint pouring device of the aforementioned type to create the also with curved object surfaces and with objects smaller dimensions a time-saving, inexpensive and enables high quality painting.

This takes place while going through the painting process no transfer of items between components of the transport facility instead, the objects to be painted remain rather, constantly fixed to one and the same holding means. This means that even with difficult courses of the varnishing object surfaces one for an optimal Painting result required alignment of the objects make. Because the transport facility is still outside the area affected by the falling paint curtain is protected against contamination by the paint. Only the holding means pass through the paint curtain, which, however, is not a further disadvantage since it are only briefly under the falling paint and can also be easily cleaned. So you can work with a continuously maintained paint curtain, who is always optimally trained. Since also a continuous It is possible to convey the objects to be painted is, the paint pouring device is very suitable for Serial painting of a large number of similar objects, also of smaller dimensions, such as those found in the automotive industry attack.

US-A-4 600 601 (cf. preamble of claim 5) known device that to the Coating printed circuit boards with an insulating layer serves, the transport device is located outside of the curtain. However, the possibility of a controlled one is missing Positioning of the holding means. A panning the circuit board held is only outside the device and also only possible to turn the circuit boards there.

Advantageous further developments of the method according to the invention and the device according to the invention are in the subclaims listed.

Fig. 1

eine bevorzugte Bauform der erfindungsgemäßen Lackgießvorrichtung in stark schematisierter Darstellungsweise,

Fig. 2

einen Querschnitt durch die Lackgießvorrichtung nach Fig. 1 in der durch Schnittlinie II-II angedeuteten, der Gießzone vorgelagerten Schnittebene,

Fig. 3

eine Ausführungsvariante der zum Festlegen der zu lackierenden Gegenstände dienenden Haltemittel, und

Fig. 4

eine schematische Darstellung einer bevorzugten Betriebsweise der Lackgießvorrichtung.

The invention is explained below with reference to the exemplary embodiments of the paint pouring device according to the invention shown in the drawing. In detail show:

Fig. 1

a preferred design of the paint pouring device according to the invention in a highly schematic representation,

Fig. 2

1 in the section plane indicated by section line II-II and upstream of the casting zone,

Fig. 3

an embodiment of the holding means used to fix the objects to be painted, and

Fig. 4

a schematic representation of a preferred mode of operation of the paint casting device.

The apparent from Fig. 1 and 2 coating device has via a first paint pouring station 10 with a pouring head 1 known type, which has an elongated shape and the underside via a longitudinal slit indicated by dashed lines 2 has. The pouring head 1 can be operated by means of a pump 3 liquid paint can be supplied from a storage container 4 dates. Any term is used here under the term "lacquer" Paint or coating material understood.

During operation of the paint pouring device, the casting head 1 liquid lacquer over the longitudinal slot 2 down, the forms a kind of coherent film, which is present is called paint curtain 5. This continuously falling paint curtain 5 falls into a bowl-like collecting device 6, the distance below the casting head 1 is arranged and the longitudinal slot 2 is vertically opposite. A return connected to the collecting device 6 7 leads the collected paint into the storage container 4 back from where it is fed to the casting head 1 again. In the line connection between the collecting device 6 and the pouring head 1 can be a processing device, not shown be interposed for a constant paint quality ensures.

The captured by the falling paint curtain 5 in operation Area is referred to as casting zone 8. Outside of this Pouring zone 8, a transport device 12 is provided, which serves to paint objects 13 of any kind transversely and in particular at right angles to the paint curtain 5 containing curtain level 14 (Fig. 4) through the paint curtain 5 to move through. The object 13 through the transport path 15 is dash-dotted in FIGS. 1 and 4 indicated. It preferably crosses the curtain level 14 at a right angle.

The exemplary transport device 12 is located to the side of the pouring zone 8, next to which it extends past. It is one of the side edges 16 of the falling Paint curtain 5 adjacent (see also Fig. 2).

The transport device 12 preferably comprises only one schematic and only partially shown transport line 17. He can be endlessly trained and self-contained be. By means of a drive motor, not shown it can be transformed into a transport movement in a Drive direction of movement indicated by arrow 18. In the exemplary embodiment, the transport movement is a circular movement. The exemplary transport strand 17 is a Link strand 23, which is formed by a chain, for example of at least two spaced, not shown Is guided.

The transport strand 17 is distributed in the direction of movement 18 a plurality of spaced-apart holding means 25 are arranged. They extend transversely to the direction of movement 18 and also across the transport path crossing the lacquer curtain 5 15. As can be clearly seen from FIG. 2, they protrude into Transverse direction away from the transport strand 17 in the manner of a boom. Consequently they are directed from the side towards the transport path 15, in the area of which they each with at least one fastener 26 are equipped with the releasable attachment allows one of the objects to be painted 13. These fasteners 26 are designed as required, which in the present case is permanent magnetic Magnetic parts is the optimal definition the example consisting of ferromagnetic metal Allow items 13. As examples for further configurations would be releasable adhesives, hook parts, clamping elements or to call suction. The latter in particular at Objects made of aluminum or other non-ferromagnetic Material.

It is provided that the objects to be painted 13 on the transport route 15 during the penetration of the paint curtain 5 permanently fixed to the associated holding means 25 stay. You will before going through the paint curtain 5 attached to a holding means 25 and are then from this towards the paint curtain 5 and transported through this. In Fig. 1 is one of the objects 13 'in front of the paint curtain 5, another (13 '') has already passed the paint curtain 5, and another (13 '' ') has the paint curtain 5 just about Pierce half. For the sake of clarity, they are further holding means 25 not shown in FIG. 1.

The 5 continuous and through the paint curtain transfer of items 13 without transfer has the advantage that the objects 13 easily aligned in a way can be an optimal painting of the paint to be painted Item surface 27 guaranteed. Noticeable this advantage is especially useful for such objects, whose surface to be painted 27 as in Embodiment is not flat, but in at least an expansion direction - indicated by a double arrow 28 - is arched. When piercing the paint curtain 5 should a respective object 13 be aligned so that the section of the curved object surface pointing in the feed direction 27 is higher than the following surface sections, that sink against the direction of transport. The optimal position is determined empirically, and then the holding means 25 and / or the fastening means 26 arranged or positioned so that the objects 13 take the desired basic object position. It is advantageous if the holding means 25 and / or the fasteners 26 with respect to the transport string 17 are adjustable.

Since the transport device 12 is outside the casting zone 8 is not from the downward flowing paint or at least not significantly contaminated. This ensures trouble-free long-term operation. Only the holding means 25 pass through the paint curtain 5 briefly into the pouring zone 8. You cross the paint curtain 5 in the area of the mentioned page margin 16. However, since it is easily possible, the holding means 25 relative training narrow, the paint loss and pollution persists within limited limits. In addition, one is at Cleaning needs to be done because of the small surfaces possible without any problems. The holding means available according to the example For this reason, 25 are shown as a rod structure Holding arms trained.

In the embodiment are only on one side Pouring zone 8 holding means 25 arranged. If necessary, however corresponding on the opposite side Holding means 25 are provided (in Figure 2 at 25 ' indicated), which then expediently on another Transport line are arranged. These are arranged in opposite directions Holding means then enforce when transporting objects the associated other side edge 16 'of the paint curtain 5 in a corresponding manner. It is therefore possible to Width of the paint curtain 5 can be better exploited by simultaneously two parallel rows of objects moved through the paint curtain 5, one from the other independent drive is possible. There is also also the ability to view a particular item at the same time to keep constantly from two sides, provided it is in favor a stable definition of objects 13 is required appears.

In those subjected to the painting process in the exemplary embodiment Objects 13 are smaller sheet metal parts Dimension, which as visible outer parts of the body Automobiles are used. Act in the special case it is metal panels that are on the B-pillar between the front and rear side windows of automobiles installed becomes. The object surface forming the visible surface 27 is slightly curved in the longitudinal direction and can transverse to it in particular run straight or likewise have a slight curvature. After the items 13 previously degreased, phosphated and possibly with a primer have been provided, the latter in particular by electrostatic paint application can be done with the invention Paint pouring device without problems first a basecoat and then pour a clear coat. If necessary you could just pour the clear coat. At it is a colorless varnish that is UV-curable can be. It has been shown that the parts in question after painting a very high quality glass-like surface have no signs of spraying have characteristic "orange peel".

The objects 13 are preferably on the holding means 25 determined that the object surface to be painted 27 faces up, d. H. one pointing upwards Has directional component, and the orientation so is taken that the direction of expansion 28 of the curvature - viewed from above vertically from above - with the direction of transport the objects 13 along the transport path 15 coincides. Of course, flat object surfaces can also be used be painted.

The objects 13 to be painted in the exemplary embodiment have in addition to the first item surface already mentioned 27 over a second object surface to be painted 27 ', which runs at an angle to the former. The present objects 13 are thin metal parts, which are folded along a longitudinal edge, so that two essentially perpendicular to each other give first and second object surfaces 27, 27 '. The exemplary coating device is now with the first Control means 32 equipped with which the holding means 25 between two stop positions shown in FIG. 2 33, 33 'in which the arranged thereon Objects 13 two different object bases 34, 34 ', in each of which one of the Object surfaces 27, 27 'for the coating application takes optimal and previously described orientation.

The exemplary coating device has a second paint casting station 10 ', the structure of which is that of the first (10) corresponds, which is why it is only dash-dotted in Figure 1 is indicated. It is the first paint casting station 10 arranged in the transport direction of the objects 13 at a distance. It is provided, for example, that a respective Item 13 successively the paint curtains 5 both Paint casting stations 10, 10 'passes through, namely the first Paint casting station 10 in the one basic object position 34 and the following second coating station 10 'in the other Object basic position 34 '. Figure 2 shows the first Object basic position 34 in the first paint casting station 10, being dash-dotted in the second paint casting station 10 'assumed second basic object position 34' and the associated second stop position 33 'is entered in order to illustrate the different orientations.

1 and 2, in which the Holding means 25 are arranged rigidly on the transport strand 17, the first control means 32 act on the transport strand 17 a. The zones of action are preferably in the next to the pouring zone 8 of a respective lacquer pouring station 10, 10 'lying area. The first control means 32 can be as indicated by rail-like guide means be in which the transport line 17 runs, and which in the two paint casting stations 10, 10 'different orientations have so that the transport strand 17 and thus also the holding means 25 fixed thereon when passing through the different positions are forced. In the embodiment are those with a U-like profile Guide means for specifying the two stopping positions 33, 33 'pivoted through 90 ° about the direction of movement 18 or twisted. The different orientations the holding means 25 in the successive paint casting processes it is recommended to pass the height of the transport strand 17 with respect to the paint curtain 5 different in the individual paint casting stations 10, 10 ' to provide, as can be seen from Figures 1 and 2. This is achieved in the embodiment by in the area of the two coating stations 10, 10 'on different Height-running transport strand 17 or - at unchanged horizontal course of the transport line 17 - due to different height arrangement of the assigned casting zone 8th.

In this context, it is advantageous if the holding means 25 have a bent course as shown. This ensures that a respective object 13 in each of the two holding positions 33, 33 'assumes a position, in which, when moving along the assigned Transport path 15 pierces the paint curtain 5. According to the example each holding device has one on the transport line 17 adjoining first section 46 and an angled end portion 47 to which the fastening means are located 26 is located. In the first item basic position 34 protrudes the holding means 25 with the first section 46 when pushing through the paint curtain 5 transversely to the transport route 15 and in particular horizontally into the paint curtain 5 and the end portion 47 protrudes upward. In the second The object section 34 'protrudes from the first section 46 in particular vertically downwards and only the end section 47 dips into the lacquer curtain via the space 42 5 a.

So while in the embodiment of FIGS. 1 and 2 first control means 32 on the support means 25 carrying Part (transport line 17) of the transport device 12 act, Fig. 3 shows a variant in which the here not shown first control means a movable Apply section 36 of the arm-like holding means 25, without influencing the position of the transport strand 17. The movable section 36 is expediently one here Pivot section, which according to the first control means 32 Double arrow 37 between the two possible positions up and is pivotable. The first tax funds can be found here for example formed by a control curve or line on which the movable sections 36 of the holding means 25 run along. It would also be possible that instead the entire holding means of a movable section are movably suspended on the transport strand 17.

It would of course also be conceivable for the paint pouring device to do this train that a single paint curtain from those to be painted Objects in different orientations is run through several times.

For an optimal design of the film-like lacquer curtain 5, the exemplary coating device has on both sides of the casting zone 8 via one of the assigned Side edge 16, 16 'of the paint curtain 5 defining edge delimiter 38, 39. It protrudes vertically starting from the casting head 1 down, but at least that of the side margin mentioned 16 assigned edge delimiters 38 at a distance above the collecting device 6 ends. That way remains a passage gap 42 for the objects 13 holding Holding means 25 Edge delimiter 38 when passing through the paint curtain 5 by they pass the passage space 42. Here are the Objects 13 fastened to the respective holding means 25 in such a way that the object surface to be painted in each case 27, 27 'in the flanks 38, 39 flanked on both sides Area of the paint curtain 5 is kept. Of the Paint application takes place in the area of optimal training the paint curtain 5 instead.

4 is a further equipment option for the paint pouring device evident. After that there are second control means 43 is present, which changes the position of the holding means 25 enable while the respectively assigned object 13 passes through the paint curtain 5. In this way it is possible special contours of the object surface to be painted 27 to take into account and their direction continuously with the passage of the paint curtain 5 in view correct to a predetermined optimal value. The second Control means 43 can, for example, for this purpose have suitable servomotors, for their control sensors 44 are present, which are the current position of each detect object 13 in the process of painting. In Fig. 4 is indicated by way of example, as a solid Lines drawn incoming item 13 initially is aligned so that the one pointing in the feed direction front surface area of the curved object surface to be painted 27 extends at right angles to the curtain plane 14. In the course of further enforcement of the paint curtain 5 is the front surface area by pivoting the Holding means 25 lowered (dash-dotted line), see above that are each under the influence of the paint curtain 5 subsequent surface areas of the object surface 27 always roughly a right angle to Have curtain level 14.

Claims (13)

1. Method for batch painting of visible exterior body parts of motor vehicles before assembly on the motor vehicle, wherein an object surface to be painted is curved in one direction, characterized in that the objects to be painted (13) are attached to holding elements (25) of a conveying device (12) located outside a paint curtain (5) and are then, while remaining attached to the respectively-assigned holding element (25), moved through the falling paint curtain (5) comprised of liquid paint at right-angles to the curtain plane (14) in such a way that the curved object surface (27) faces upwards and the direction (28) in which the curve extends, viewed from above, coincides with the direction of movement and wherein, on passing through the paint curtain (5), the objects to be painted (13) are held in the paint curtain (5) by a section lying outside the paint curtain (5) and assigned to one or more of the side edges (16) of the paint curtain (5), and the alignment of the objects to be painted (13) while passing through the paint curtain (5) is influenced by controlled positioning of the holding elements (25).
2. Method according to claim 1, characterized in that, for consecutive painting of two object surfaces (27, 27') of an object (13), the objects to be painted (13) are left in an unchanged position on the respectively-assigned holding element (25), and the different basic object positions (34, 34') required are obtained by changing the position of at least one section (36) of the holding elements (25).
3. Method according to claim 2, characterized in that the changeover between the two basic object positions (34, 34') is effected by a change in position of the elements (17) of the conveying device (12) which support the holding elements (25).
4. Method according to any of claims 1 to 3, characterized in that the object surface (27) to be painted is provided with a poured-on clear coat and preferably beforehand with a poured-on base coat.
5. Curtain painting device for the painting of motor vehicle body parts, with a feeding head for producing a paint curtain (5) of liquid paint flowing downwards, with a collecting device (6) for unused paint from the paint curtain (5) arranged at a distance below the feeding head (1), and with a conveying device (12) located outside the area covered by the falling paint curtain, for conveying the objects to be painted (13) on a transfer path (15) crossing the paint curtain (5) at right-angles to the curtain plane, in particular for implementation of the method according to any of claims 1 to 4, characterized in that the conveying device (12) is provided with holding elements (25) which permit releasable individual attachment of curved objects to be painted (13) in such a way that any curved object surface (27) faces upwards, wherein the objects to be painted (13) remain on the holding elements (25) while passing through the paint curtain (5), that the conveying device (12) is located at the side of the pouring zone (8) when the paint curtain (5) is in operation and the holding elements (25) are directed from the side to the transfer route (15) crossing the curtain plane (14) so that in passing through the paint curtain (5) they cross it in the area of one or more side edges (16), and that controls (43) to change the position of the holding elements (25) or at least a section of them are provided, in order to influence the alignment of the respective objects to be painted (13) which are attached to them, while passing through the paint curtain (5).
6. Device according to claim 5, characterized in that the conveying device (12) has one or more circulating conveyor lines (17), expediently in the form of link chains (23), to which a large number of holding elements (25) are attached at intervals.
7. Device according to claim 5 or 6, characterized in that the paint curtain (5) is maintained constantly between the individual painting operations.
8. Device according to any of claims 5 to 7, characterized in that the holding elements (25) are in the form of holding arms, in particular with a bar structure.
9. Device according to any of claims 5 to 8, characterized in that the fasteners (26) for the objects to be painted (13) provided on the holding elements (25) are in the form of magnet elements or clamping elements.
10. Device according to any of claims 5 to 9, characterized in that controls (32) to change the position of the holding elements (25) or at least a section (36) of them are provided, in order to preset different alignments for the respectively-attached objects to be painted (13) for at least two consecutive curtain painting operations and in particular for the consecutive passage of several successively-arranged paint curtains (5).
11. Device according to any of claims 5 to 10, characterized in that the controls (32, 43) act on the elements of the conveying device (12) which support the holding elements (25).
12. Device according to any of claims 5 to 11, characterized in that the controls (32, 43) act on a movable section (36) of the holding elements (25), while the position of the elements (17) of the conveying device (12) which support the holding elements (25) remains unaffected.
13. Device according to any of claims 5 to 12, characterized in that the paint curtain (5) is provided with side edge limiters (38, 39) extending downwards from the feeding head (1), wherein the holding elements (25) are so arranged that, in passing the pouring zone (8), they engage beneath the assigned edge limiter (38) which terminates with clearance above the collecting device (6) and hold the object (13) attached to them in such a way that the latter extends, with the object surface (27) currently to be painted, into the area of the paint curtain (5) flanked on either side by the edge limiters (38, 39),

Images