DE202019005366U1 - Automatic painting system - Google Patents

Abstract

Automatic painting system comprising a robot, a workpiece or substrate holding device (12) by which a workpiece (4) is held during a painting process, a workpiece feed device, a workpiece removal device and an atomizer (6) for painting the workpiece (4), CHARACTERIZED THAT the atomizer (6) is arranged in a fixed position in the painting system in a painting position during the painting process, that the robot (2) comprises a workpiece holding device (12) with which the workpiece during the painting process is in relation to the stationary atomizer (6) can be moved.

Description

The invention relates to an automatic painting system comprising a robot, a workpiece or substrate holding device, by means of which the workpiece is held during a painting process, a workpiece feed device and a workpiece removal device.

State of the art

With such painting systems, the substrate or workpiece is painted completely automatically. First, the workpiece to be painted can be fed to a processing area via a feed device and automatically painted in this painting area with the aid of the robot, the robot ensuring that even complex three-dimensional geometries are painted. The painted workpiece can then be removed from the processing area by a removal device.

An automated painting system of the type mentioned comprises a robot or another type of handling device, in particular an articulated arm robot, particularly preferably a 6-axis articulated arm robot, and a tool or substrate holding device on which the workpiece is arranged, possibly comprising an upper and lower holder for the substrate.

In particular, the handling of the air and the exhaust air is associated with a very high outlay in such painting systems. The air must first be filtered, washed, then dried, moistened in a defined manner and finally heated before use before it is fed into the processing room with the painting system as supply air.

In the immediate vicinity of the painting system there is also an air extraction system which is adapted to the size of the painting area and which realizes a defined air flow when painting in the painting area. Naturally, the larger the painting area, the larger the air extraction. Overall, the air conditioning and exhaust air extraction is thermodynamically very complex in the prior art and in such painting systems and therefore expensive.

In the prior art, the individual system components of the painting system, i.e. the robot, the flushing of the paint supply lines, the workpiece feed, the workpiece removal, the handling, the cleaning of the workpiece holder and the atomizer, the cabin or the ventilation and so on are arranged sequentially that is, always in succession in individual successive process steps. Such systems are e.g. offered by the companies KUKA or Dürr or also by Eisenmann, Krautzberger etc.

In many cases, existing automatic painting systems use an electrostatic high-speed rotary atomizer (HR atomizer) in which the paint to be applied to the substrate is sprayed or distributed electrically charged from a nozzle and applied to the workpiece charged in the opposite pole, so that the color is drawn or attracted to the substrate by the charge difference.

In the prior art, the electrostatic high-speed atomizers or other atomizers, hereinafter referred to as “atomizers”, are arranged on a movable actuating end of a robot arm, in particular an articulated arm robot, and are thus applied to the substrate with the robot, the robot often having linear paths along the surface of the Substrate leaves and thus wets the surface of the substrate with the paint or varnish. Since the atomizer is thus arranged at the end of the robot arm and is therefore movable with the robot arm, all supply lines for the atomizer must be fed to the robot and routed around or through the robot to the atomizer. Therefore, relatively long lines are required to supply the atomizer at the end of the robot, which can often be 5 m and longer. In particular, the high-voltage cables required to supply the electrostatic atomizer move with it, which is always critical because of the high voltage of 100 kV. In addition, the hydraulically supplying air hoses can kink and thus impair - often difficult to see - the painting results.

Basically, the size of the atomizer used essentially determines the size of the robot to be used. A robot can only be used to handle an object up to a certain weight and up to a certain size. The robots of interest in this invention handle e.g. Weights of up to 10 kg and have a radius of at least 1.1 m.

In particular, when changing the color, it is necessary to change the entire atomizer, for which the atomizer located at the end of the robot arm has to be moved to a parking position, is set down there, the first atomizer is released from the end of the robot arm, and a second atomizer is connected to the robot arm and then operation with the second atomizer for the second color can be started. In terms of process technology, it is also possible to apply a second color with the same atomizer, but then the time-consuming rinsing of the 5 meter long paint lines is necessary, which is more time-consuming.

In existing painting systems, the robot is more or less stationary, so that the other system components have to be positioned in relation to it or moved towards it, e.g. the workpieces, i.e. a workpiece holder for workpieces that have not yet been painted and a workpiece rest for finished painted workpieces. This is preferably done on conveyor belts, chain conveyors or the like.

However, the fundamental problem remains that relatively large atomizers require the use of relatively large robots with large radii of movement, which is absurd for the handling of actually smaller and light workpieces.

Sometimes it is necessary to apply several layers of lacquer and different layers of lacquer to a workpiece one after the other, for which in turn different atomizers are required which have to be replaced.

More recent areas of application increasingly include the painting of essentially smooth three-dimensional structures with curvatures, edges and highlights, in which case the robot has to traverse certain corners and edges in order to completely wet the corresponding areas with paint and color.

Depending on the geometry of the substrate, various programs have to be learned or taught to the robot so that it optimally wets the substrate with paint or varnish on the surface.

• Spritzen und Sprühen: Die häufigsten Auftragungsarten in der Lackindustrie sind Sprühen und Spritzen. Zum Aufsprühen werden Druckzerstäuber benutzt, die den Lack mittels Kompressor im Niederdruck (0,5 - 0,7 bar), Hochdruck (1-8 bar) oder Airless-Verfahren (60-250 bar) auftragen. Dieses wird häufig auch als „pneumatische Lackierung“ bezeichnete.

In industry, the following coating processes are used in series production:

• Spraying and spraying: The most common types of application in the paint industry are spraying and spraying. Pressure atomizers are used for spraying and apply the paint using a compressor at low pressure (0.5 - 0.7 bar), high pressure (1-8 bar) or airless process (60-250 bar). This is often referred to as "pneumatic painting".

Dip painting: A workpiece is immersed in the paint. In electrocoating, an electric field of 50-300 V is applied in a paint solution with suitable film formers and the workpiece is connected as an earth. The electro-dip coating was developed by Ford as an anodic dip coating to produce a protective coating for cars and is now used as a cathodic dip coating in the entire automotive industry.

Electrostatic spraying process: This process uses an electrostatic high voltage field of 80 to 150 kV. Rotating paint atomizers (high-speed rotary atomizers) are often used. Pigment-free binder powders are used for solvent-free powder coatings. The process was introduced in the paint industry in 1965. In powder coatings and other coatings, ionic substances (e.g. sodium dodecyl sulfate) with an electrical charge are introduced into the film former (e.g. epoxy resin). Powder coatings can be charged electrically using a high-voltage electrode. Applying an electrostatic primer to materials such as plastic or metals significantly reduces paint consumption when spraying paint. This process takes place fully automatically with robots.

The state of the art offers automated paint sample application systems for gravity cup or automatic spray guns and also HR atomizers for the quality inspection and development of OEM paints. With these systems, the paint is applied to level test panels using the spray guns. As a rule, the painting head is advanced in the horizontal direction and the test plate workpieces in the vertical direction.

For many standard paints, the test paint on flat test sheets is sufficient for quality control and in the ongoing paint development. Spatial, 3-dimensional spray patterns, also called car shape or frog, are increasingly being used for sophisticated car paints and effect paints.

The advantage of these substrates is the possibility of being able to check the color sample shapes, color tones and effect sequences before processing and to get a realistic forecast for the finished surface image on the series object. These are clear advantages in quality control and ongoing coating development for such designer coatings.

Due to the free-form surfaces of the spatial test samples, however, according to the current state of the art, the existing partially automated painting pattern application systems cannot be used, since so far only the feed in two geometric axes has been possible here.

In industry, the workpieces or substrates have so far generally been flat test sheets manually, pneumatically or with 2D machines (pneumatic - and / or electrostatic) for quality control and in ongoing paint development. painted. The spray pattern is positioned statically and the feed of the high-speed rotary atomizer is carried out by means of a robot, in particular an industrial robot. The significant space requirements and the high investments for such systems are disadvantageous. Production program planning and utilization of such “series plants” with test samples can also be regarded as inefficient.

The disadvantages of the manual pressure atomizer process are fluctuations in the paint coating due to the lack of reproducible parameterization, the longer coating time and the need for highly specialized personnel. This coating process cannot be used for many of the high-end designer coatings.

task

Based on this prior art, the object of the invention is to at least partially avoid the associated disadvantages and to further develop an automatic painting system in such a way that the operational and investment costs of quality testing of sophisticated paints or the development costs of paints are significantly reduced.

invention

According to the invention, this object is achieved by the features of the independent claims, preferred but not mandatory further developments are given in the subclaims.

In the simplest embodiment, this object is already achieved in that the atomizer or a spray gun is arranged in a fixed position in a painting position in the painting system, and that the robot comprises a workpiece holding device with which the workpiece to be painted in relation to the stationary atomizer during a painting process a painting room can be moved.

The atomizer is preferably designed as an electrostatic HR atomizer. In any case, however, the atomizer is arranged in a stationary manner during the painting process and the centrally arranged robot moves the workpiece in such a way that the workpiece is moved in relation to the stationary spray opening of the atomizer.

According to the invention, the robot therefore only handles the workpiece or substrate, and therefore no longer the relatively heavy atomizer, in particular the electrostatic rotary atomizer. In this respect, the invention offers a particular advantage, particularly in the case of the relatively heavy HR atomizers.

In contrast to the prior art, in which the sequence of the individual processing steps takes place serially, that is to say one after the other, the handling and coordination of the overall process can now be implemented centrally by the robot, which thus represents the central handling unit, which is preferably arranged centrally and around which around the other system components are arranged away optimized. In addition to the actual painting movement, the robot according to the invention can also, among other things. handling (e.g. picking up and placing the workpiece) so that separate units are no longer required.

Due to the modular concept, the painting system according to the invention can be used in particular for an inexpensive, largely automated painting of small series parts.

Since the invention is particularly suitable for smaller workpieces or substrates, i.e. with a weight of 0-10 kg, in particular 0-5 kg, which only have to be moved in a range of approximately 800 mm, for which the robot has a circle of approximately 400 mm in the range of motion, significantly smaller robots can be used, which can therefore be moved faster due to the lower mass inertia. This speeds up the painting process while improving the painting result.

This enables a highly efficient and cost-effective paint inspection on spatial substrates for the first time. The system provided is extremely space-saving because the painting head is arranged almost stationary and the substrate is guided kinematically. A HRZ quick-change system and a universal HRZ master / adapter system can be used to further increase efficiency. A non-reproducible manual test coating or an inefficient application on a serial system of spatial spray samples are a thing of the past.

Because painting is only carried out at a predefined point, the painting area of the painting system is reduced to a minimum, which means that the conditioning units for the air are made significantly smaller, and overall air handling can be reduced. In particular, the air extraction can be made 2 to 3 times smaller than in the prior art.

The painting system includes active functional components for the effective area of the high-voltage field of the HR atomizer as well as the resulting spray mist, in particular a newly developed actuator and sensor system for the workpiece-carrying robot with appropriate shielding. Grounding the robot largely excludes the risk of high-voltage damage due to defective insulation, which is more common in conventional systems due to the moving cables. If necessary, the sensors can also be positioned outside the HS field or shielded by metal sheets. In connection with the high-voltage field and the HRZ changing system positioned in the painting booth, high-voltage-resistant assemblies are also provided. A special innovation is the universal HRZ master / adapter system in the smallest of spaces with high-voltage connections.

• - Für die Bewegung von kleinen/leichten Werkstücken, insbesondere Werkstücke mit einer Abmessung von bis 40 x 60 cm und einem Gewicht bis 5 kg müssen nur kleine Roboter eingesetzt werden, die aufgrund der geringeren Massenträgheit auch schneller bewegt werden können. Für konventionelle Systeme ist, insbesondere bei HR-Zerstäubern mit 6 - 10 kg ein entsprechend größerer Roboter nötig.
• - Insbesondere der HR- Zerstäuber ist durch die starre Montage vor starken Beschleunigungen bei hohen Lackiergeschwindigkeiten geschützt, weil die sich drehende Welle sich Richtungsänderungen widersetzt.
• - Es sind lediglich kurze Farbleitungen zur Farbversorgung mit einer Länge von maximal etwa 1 Meter erforderlich. Dieses realisiert einen geringen Farbverlust bei kleinen Chargen, ermöglicht ein einfaches und schnelles Spülen bei Farbwechsel und vereinfacht insgesamt die Wartung.
• - Kurze Luftschläuche von maximal 0,5 Metern zum Zerstäuber ermöglichen ein besonders schnelles Regelverhalten;
• - Das Werkstückhandling wird vom Roboter realisiert, was eine einfache Integration von Zu- und Abführbändern ermöglicht, so dass hierfür keine separate Steuerung notwendig ist.
• - Systeme zum einfachen/schnellen Zerstäuberwechsel sind einfach zu integrieren. Da der Zerstäuber „quasi-starr“ angeordnet ist, also beim Lackieren nicht bewegt wird, ist z.B. ein Schwenken eines Doppel-Zerstäuberhalters um 180° zwischen zwei Lackierschritten möglich. Alternativ kann unter dem Zerstäuberhalter ein Revolver-Magazin mit automatischem Wechsel zwischen Lackierschritten montiert sein. Hierzu kann eine besondere Halteanordnung für ein einfaches Wechseln der Zerstäuber eingesetzt werden, wie dieser in der Patentanmeldung DE 10 2018 108 786.1 der Anmelderin beschrieben ist.
• - Durch die stationäre Anordnung des Zerstäubers wird der abzusaugende Bereich bzw. Lackierraum auf ein Minimum reduziert. Damit wird die Konditionierung der Luft entscheidend vereinfacht.

The configuration according to the invention has decisive advantages:

• - For the movement of small / light workpieces, especially workpieces with a dimension of up to 40 x 60 cm and a weight of up to 5 kg, only small robots need to be used, which can also be moved faster due to the lower inertia. For conventional systems, especially with HR atomizers with 6 - 10 kg, a correspondingly larger robot is necessary.
• - The HR atomizer in particular is protected from strong accelerations at high painting speeds by the rigid assembly, because the rotating shaft opposes changes in direction.
• - Only short paint lines for paint supply with a maximum length of about 1 meter are required. This realizes a small loss of color in small batches, enables simple and quick rinsing when changing colors and overall simplifies maintenance.
• - Short air hoses of maximum 0.5 meters to the atomizer enable particularly quick control behavior;
• - The workpiece handling is carried out by the robot, which enables easy integration of infeed and outfeed belts, so that no separate control is necessary for this.
• - Systems for simple / quick atomizer change are easy to integrate. Since the atomizer is arranged "quasi-rigid", ie it is not moved during painting, it is possible, for example, to swivel a double atomizer holder by 180 ° between two painting steps. Alternatively, a revolver magazine with an automatic change between painting steps can be installed under the atomizer holder. For this purpose, a special holding arrangement can be used for a simple change of the atomizer, such as that in the patent application DE 10 2018 108 786.1 the applicant is described.
• - Due to the stationary arrangement of the atomizer, the area to be extracted or the painting area is reduced to a minimum. This significantly simplifies air conditioning.

The painting system can be equipped with an automatic tool and workpiece changer, which equips and sets up the substrates and then operates them fully automatically.

Embodiments also provide for handling of the workpieces or substrates by means of a suction device, which is preferably arranged at the working end of the robot and can hold the workpiece there. This handling can include a positioning aid, which additionally engages the workpiece in a positioning manner. This positioning aid can e.g. include a covenant or paragraph.

Embodiments include a cleaning unit for removing excess paint or lacquer from the system components, which are also sometimes referred to as overspray cleaning systems. Such a cleaning unit preferably comprises a cleaning chamber integrated in the paint system, into which the free end of the robot arm with the workpiece holding device can enter through an opening. Spraying with a cleaning agent and additionally cleaning with a brush or comb can then take place in this cleaning chamber, e.g. by rotating the workpiece holder in this chamber.

The existing robot thus takes over the positioning of the workpiece in the cleaning device. Systems known from the prior art require additional separate devices for this.

Examples of products that can be painted with the painting system according to the invention are e.g. Cell phone cases, cell phone cases and the like.

Sometimes the atomizer is also changed by providing a pivot axis about which two or more atomizers can be pivoted and changed into the respective working or painting position.

Embodiments include, in particular to simplify the atomizer change on the stationary atomizer holder, a quick change system, in particular like this in the patent application DE 10 2018 108 786.1 the applicant is disclosed

In addition to the painting system, the invention also relates to a painting process for painting or coating a workpiece comprising a three-dimensional surface with a lacquer, a paint or the like using a robot, in particular designed as a 6-axis articulated arm robot, and an atomizer for applying the lacquer to the workpiece or the workpiece surface. The painting process comprises the steps of picking up the workpiece with the robot from a workpiece supply unit, painting the workpiece by moving the workpiece in a painting area in front of a stationary atomizer, and depositing the painted workpiece in a workpiece removal unit. According to the invention, the atomizer is arranged stationary and immovable in a painting position during a painting process and only the workpiece is moved anywhere in the room by the robot in the painting area.

In the following detailed description, reference is made to the accompanying drawings, which form a part of this specification of the invention and which are shown by way of illustration to illustrate specific embodiments with which the invention may be practiced. In this regard, directional terminology such as "top", "bottom", "front", "back", "front", "back", etc. is used in relation to the orientations of the figure (s) described. Because components of embodiments can be positioned in a number of different orientations, the directional terminology is illustrative and is in no way limiting. It is understood that other embodiments may be used and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description is not to be taken in a limiting sense. In the context of this description, the terms “connected”, “connected” and “integrated” are used to describe both a direct and an indirect connection, a direct or indirect connection and a direct or indirect integration. Identical or similar elements are provided with identical reference symbols in the figures, insofar as this is expedient.

Reference symbol lines are lines that connect the reference symbol to the relevant part. An arrow, on the other hand, that does not touch any part, refers to an entire unit to which it is directed. Incidentally, the figures are not necessarily to scale. Certain areas may be exaggerated to illustrate details. In addition, the drawings can be simplified and do not contain every detail that may be present in the practical implementation.

• 1 eine schematische Seitenansicht eines erfindungsgemäßen Lackiersystems; und
• 2 eine vergrößerte isometrische Ansicht einer Werkstückhaltevorrichtung ausgebildet als Tassenhalter; und
• 3 eine Vorderansicht im Schnitt des Tassenhalters gemäß 2.

Show it:

• 1 a schematic side view of a painting system according to the invention; and
• 2nd an enlarged isometric view of a workpiece holding device designed as a cup holder; and
• 3rd a front view in section of the cup holder according 2nd .

The 1 shows an automatic quick-change system according to the invention comprising the 6-axis articulated arm robot 2, hereinafter simply referred to as “robot”, which is attached to a floor with an assembly end and is freely movable in space with an actuation end on which an exemplary, shell-shaped workpiece 4th is arranged.

Next to the robot is an atomizer 6 aligned in a painting position that is stationary for the painting process, but overall in an HRZ quick-change / turret system 8th integrated, through which the atomizers for a color or paint change can be easily changed. The whole painting unit is through a control unit 10th controllable by a user.

The robot 2nd sits with its lower fastening end on a base or is connected to it in a stationary manner and picks up the workpiece at its upper or freely movable actuating end with 4 by means of a workpiece holding device designed to hold this workpiece. By moving the robot 2nd the workpiece can be moved anywhere in the three-dimensional space around the robot to carry out the painting using the stationary on the HRZ quick change / turret system 8th arranged atomizer 6 , which is arranged in the horizontal and on the robot 2nd sprayed too directed.

The 2nd and 3rd show enlarged views of a as a cup holder 12 trained workpiece holder. The cup holder 12 has a main plate extending transversely to its longitudinal axis 12a on, which is in the installation position transverse to the longitudinal axis of the actuating end of the robot 2nd extends and on this over a bridge-like mounting bracket 12b is flanged, which in turn is on the top of the main plate 12a this is screwed on bridging. The main plate points to the bottom 12a an annular cup holder 12c on the one inside the cup 14 Centering spigot engaging in installation position 12d is trained. This centering piece 12d thus realizes an exact positioning of the cup 14 in relation to the cup holder 12 and therefore on the robot 2nd . Extending in the longitudinal direction is on the underside of the centering nozzle 12d a pneumatically operated suction cup 12e arranged with which the cup 14 with the cup holder 12 can be removed from the workpiece supply, can be painted with the atomizer and can be placed in a workpiece holder.

Reference symbol list

2nd

robot

4th

workpiece

6

Atomizer

8th

HRZ quick change / turret system

10th

Control unit

12

Cup holder

12a

Main plate

12b

Mounting bracket

12c

Cup holder

12d

Centering spigot

12e

Mammal

14

Cup

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102018108786 [0036, 0043]

Claims (7)

Automatic painting system comprising a robot, a workpiece or substrate holding device (12) by which a workpiece (4) is held during a painting process, a workpiece feed device, a workpiece removal device and an atomizer (6) for painting the workpiece (4), CHARACTERIZED THAT the atomizer (6) is arranged in a fixed position in the painting system in a painting position during the painting process, that the robot (2) comprises a workpiece holding device (12) with which the workpiece during the painting process is in relation to the stationary atomizer (6) can be moved. Painting system according to Claim 1 , CHARACTERIZED BY THE fact that the atomizer (6) is integrated in an atomizer changing device (8) with which several atomizers (6) can be transferred into the painting position. Painting system according to Claim 2 , CHARACTERIZED BY THAT the atomizer changing device (8) is designed in the manner of a revolver magazine , with which at least two atomizers (6) can be moved between the painting position and a rest position. Painting system according to one of the preceding claims, CHARACTERIZED IN THAT this comprises a cleaning unit for removing excess paint from the system components. Painting system according to Claim 4 , CHARACTERIZED BY THE fact that the cleaning unit comprises a cleaning chamber into which the free end of the robot arm with the workpiece holding device can move through an opening. Painting system according to Claim 5 , CHARACTERIZED THAT the cleaning chamber comprises a spray device for at least partially spraying the workpiece holding device (12) with cleaning agent. Painting system according to one of the Claims 4 to 6 , CHARACTERIZED BY THE cleaning unit comprising a brush, a comb, dry ice or another cleaning device for cleaning the workpiece holding device , preferably when the workpiece holding device (12) rotates in this cleaning chamber.

Images