EP2821147B1 - Coating system and coating method - Google Patents

Description

The invention relates to a coating installation for coating workpieces with at least one receiving mandrel for receiving at least one workpiece, a conveying device with which the receiving mandrel can be conveyed to processing stations, a painting station in which the at least one workpiece can be coated on the receiving mandrel with a lacquer, and a Hardening station, in which the at least one workpiece on the mandrel is irradiated in a protective gas atmosphere by means of an irradiation device, wherein the lacquer cures, according to the preamble of claim 1.

The invention further relates to a method for coating workpieces, in which at least one workpiece is arranged on a mandrel, the mandrel is conveyed with the at least one workpiece by means of a conveyor to processing stations, in a painting the at least one workpiece on the mandrel with a paint is coated and irradiated in a curing station the at least one workpiece on the mandrel in a protective gas atmosphere by means of an irradiation device, wherein the lacquer cures, according to the preamble of claim 11.

A generic coating system and a corresponding coating process, for example, from the WO 2007/045442 A1 out. The coating system described herein, in which the workpieces pass through a larger protective gas range, makes sense for mass production of relatively large workpieces. For economical operation, the protective gas chamber should be as small as possible in order to minimize the consumption of inert gas.

The invention has for its object to provide a coating system and a coating method, which allow even for smaller parts a particularly economical coating.

The invention is achieved, on the one hand, by a coating installation having the features of claim 1 and, on the other hand, by a coating method having the features of claim 11. Preferred embodiments are given in the dependent claims.

The coating system according to the invention is characterized in that the receiving mandrel is pivotable between a horizontal first working position and a vertical second working position, that the receiving mandrel is pivoted with the at least one workpiece in the painting station in the horizontal working position and that the mandrel with the at least one workpiece in the curing station is pivoted to the vertical second working position.

A basic idea of the invention is to carry out the painting of workpieces in a horizontal mandrel, while the curing of the coated workpiece is carried out in a protective gas chamber in a second vertical working position. This allows on the one hand effective painting in a horizontal orientation and a protective gas-saving curing in a vertically oriented protective gas chamber. In particular, the receiving mandrel may be formed lance or rod-shaped, so that it can also accommodate elongated and thus relatively bulky workpieces. On the elongated mandrel but also several workpieces can be mounted by means of appropriate brackets. The mandrel may be connected to the conveyor fixed or detachable via a holding unit.

A preferred embodiment of the invention is that the curing station has a protective gas chamber, which comprises a protective gas bell with a lower access opening. This arrangement is particularly useful for receiving inert gas, which is lighter than the ambient air. The supply of the workpiece takes place via a relative vertical lifting movement between the protective gas bell and the workpiece.

In principle, the mandrel can be retracted with the at least one workpiece in the protective gas bell. According to one embodiment of the invention, it is particularly advantageous for the protective gas bell to be vertically movable between a lower hardening position in which the locating mandrel is enclosed in the vertical working position and an upper feed position in which the locating mandrel can be positioned under the protective gas bell in the vertical working position , The lance-shaped mandrel can take a vertical position in the curing station, in which a small footprint is needed. In this vertical position, the sleeve-shaped protective gas bell, which has side walls and a closed ceiling area, is then moved vertically from above over the workpiece, so that the protective gas atmosphere arranged in the protective gas bell encloses the workpiece. In addition, in this stroke movement from above harmful residual oxygen can be displaced down through the lower access opening of the protective gas bell. The lifting movement of the protective gas bell can be effected by a lifting drive, in particular a setting cylinder.

According to a further embodiment of the invention, it is particularly efficient that the irradiation device is mounted in or on the protective gas bell and can be moved with it. The irradiation devices are arranged on the side walls and / or the ceiling area, so that a sufficient irradiation of the coated workpiece areas is ensured.

The irradiation device can be any irradiation device, in particular also a heating device. However, it is particularly preferred according to the invention that the irradiation device comprises at least one UV emitter. This irradiation device is intended for UV-curable coatings. These ultraviolet light-curable coatings have long been known and are widely used for efficient coating and painting of workpieces.

A particularly good painting and compensation of the influence of gravity on the coating thickness is achieved according to a preferred embodiment of the invention in that the receiving mandrel for rotating the at least one workpiece is rotatably mounted and driven. In particular by a Turning the lance-shaped receiving mandrel with the at least one workpiece in the horizontal first working position can be achieved that avoided during painting a flow of the applied paint in the direction of gravity or largely prevented. As a result, lacquer layers having a particularly uniform lacquer layer thickness can be achieved, in particular during painting. Even in the curing station in the vertical second working position, a rotation of the receiving mandrel may be useful so as to ensure a uniform irradiation of all workpiece areas. The mandrel is designed as a rotatably mounted spindle. On each mandrel or each holding unit may be provided a rotary motor.

In principle, any suitable transport device, in particular revolving conveyors, can be provided as conveying device. According to a variant of the invention, it is preferred that the conveying device has a rotary indexing table on which a plurality of receiving mandrels are pivotably mounted. The receiving mandrels or the holding units for the receiving mandrels are arranged distributed uniformly along the circumference of the rotary indexing table. At the rotary indexing tables, a corresponding pivot drive is provided, with which the receiving mandrels between the horizontal first working position and the vertical second working position are pivotable. The rotary actuator can have an electric motor or a pneumatic or hydraulic actuating cylinder. A pivoting means of a sliding mechanism in the cyclic further rotation of the rotary indexing table is possible. The processing stations are distributed uniformly along the circumference of the rotary indexing table, so that the workpieces can be further promoted by a processing station at each clocking step.

According to a further embodiment of the invention, it is particularly advantageous that further processing stations are arranged along a conveying path of the conveying device, in particular a feeding station, a cleaning station, a flame station, an ionizing station and / or a removal station. The abandonment of the workpieces or the removal of the finished painted and hardened workpieces can be done manually or via an automatic gripper. In the cleaning station, degreasing by means of liquid or by blowing off dust particles can take place. In the Beflammstation can do another cleaning in a thermal way be carried out under the influence of one or more gas burners. In an ionizing station, an electrical charging can be reduced or avoided by an appropriate loading of the workpiece, so that in particular dust deposits are avoided immediately before painting in the painting station.

A preferred development of the invention consists in that an air lock is arranged at least between two adjoining processing stations. Between the individual stations partition walls are provided with a through hole in principle. The passage opening is aligned horizontally or vertically according to the respective working position of the mandrel during the passage. In order to seal off the individual processing stations from each other, corresponding access doors and / or preferably air lock chambers can be provided. The airlock chamber can be used to ensure with high certainty that either no dust-laden air penetrates into the coating station or no air loaded with paint particles escapes to the outside. The air locks can be designed such that they have a certain negative pressure or overpressure compared to the pressure in the painting station. This relative pressure difference can be effected either by a pressure setting in the painting station or in the airlock. Of course, airlocks can also be provided between other processing stations, as far as necessary.

The protective gas in the curing station can be selected according to the applied coating or the paint. In principle, noble gases or CO _{2 are} possible as inert gas, which can be influenced by heating in their density so that they are lighter for use in a protective gas bell than the surrounding air atmosphere.

However, it is particularly preferred according to the invention that nitrogen is provided as a protective gas. This is basically lighter than the surrounding air atmosphere. In addition, nitrogen is a major constituent of the surrounding air atmosphere and does not present an impurity when it exits. In addition, nitrogen volatilizes upwards to the hall ceiling and, unlike carbon dioxide, can not form dangerous concentrations near the bottom. In the protective gas bell is preferably provided in the ceiling area a feeder, with which continuously or discontinuously new protective gas can be supplied to compensate for unavoidable protective gas losses during operation. The feed device is preferably arranged in the region of the irradiation device such that the inflowing protective gas cools the irradiation device and at the same time the protective gas is heated even before it enters the protective gas bell. This targeted heating of the protective gas additionally reduces outlet losses through the lower access opening when using a protective gas bell.

The object mentioned above is achieved with respect to the method according to the invention in that the mandrel is pivoted between a horizontal first working position and a vertical second working position that is pivoted for painting in the painting of the mandrel with the at least one workpiece in the horizontal first working position and in that, for hardening in the hardening station, the receiving mandrel with the at least one workpiece is pivoted into the vertical second working position.

The method is intended in particular for implementation with the above-described coating system. With the coating method, the aforementioned advantages can be achieved.

Fig. 1

eine perspektivische Ansicht auf eine erfindungsgemäße Beschichtungsanlage;

Fig. 2

einen schematischen Horizontalschnitt durch die Beschichtungsanlage von Fig. 1; und

Fig. 3

einen schematischen Vertikalschnitt gemäß dem Schnitt A-A in Fig. 2.

The invention will be explained in more detail with reference to a preferred embodiment, which is shown schematically in the accompanying drawings. In the drawings show:

Fig. 1

a perspective view of a coating system according to the invention;

Fig. 2

a schematic horizontal section through the coating system of Fig. 1 ; and

Fig. 3

a schematic vertical section along the section AA in Fig. 2 ,

A coating system 10 according to the invention has according to Fig. 1 a housing 14 encapsulating the plant. In the illustrated embodiment are a loading station 30 and a removal station 70 designed for the workpieces 5 as manual workstations. On the side walls of the housing 14 access doors are provided with windows 15 to the individual processing stations. Functional components, such as an operating unit 18 and a control cabinet 16, are arranged on the outside of the housing 14, so that they are easy to operate and maintain.

The further structure of the coating system 10 is in connection with the FIGS. 2 and 3 explained. As essential processing stations a painting station 40 and a curing station 50 are provided within the housing 14. About a rotary indexing table 22 as a conveyor 20 to be coated workpieces 5 are promoted from the feeding station 30 to the individual processing stations gradually with a rotational movement. A total of four workpieces 5 are mounted on a lance or spit-like receiving mandrel 12. The mandrels 12 with the workpieces 5 are brought about by means of transport vehicles to the loading station 30, where they are manually attached to holding units 26 on the rotary table 22 in the illustrated embodiment manually. The holding units 26, which are distributed uniformly along the outer circumference of the rotary indexing table 22, may have a clamping device for fixing the plugged-on receiving mandrel 12.

At the feeding station 30, the receiving mandrels 12 are attached to the workpieces 5 in a vertical first working position. In a conveying step, the receiving mandrel 12 is then conveyed further into a cleaning station 32. In the cleaning station 32, the workpieces 5 are cleaned of dirt, in particular degreased. In a further clocking step, the receiving mandrel 12 can then be moved further with the cleaned workpieces 5 to a flaming station 34. It can be done here by an additional activation of the surface by flaming by means of a gas burner. This is followed by further conveying to an ionizing station 36 in order to avoid electrical discharges and thus static adhesion of dust.

Subsequently, the receiving mandrel 12 is further conveyed with the workpieces 5 via a chamber-like airlock 38 in the painting 40. In the cleaning station 32, the Beflammstation 34 and the ionizing station 36 is the Take-up mandrel 12 with the workpieces 5 in the horizontal second working position, in which the mandrel 12 has been pivoted after a vertical retraction into the cleaning station 32 by a corresponding pivot drive on the holding unit 26. The individual stations are separated by partitions 19 from each other. In the partitions 19 through holes 28 are provided for the passage of the receiving mandrels 12 with the workpieces 5. According to the horizontal alignment of the receiving mandrels 12, these through-holes 28 are formed as substantially horizontal slots.

In the coating station 40, the workpieces 5 are coated on the receiving mandrels 12 in a total of two steps with a UV-curable lacquer. For paint coating a painting robot 42 is fixedly arranged in a receiving area 17 above the rotary indexing table 22. By means of a suction and filter unit 44 in the painting station 40, spray mist can be sucked off and filtered off during spraying of the paint. The horizontally arranged receiving mandrels 12 with the workpieces 5 are rotated during painting about its longitudinal axis by means of a rotary motor. After coating of the workpieces 5 in the coating station 40, the receiving mandrels 12 with the workpieces 5 are conveyed further into a second airlock 48 which, like the first airlock 38, prevents unwanted escape of paint particles loaded with paint particles from the coating station 40. For this purpose, the chamber-like coating station 40 relative to the two adjacent air locks 38, 48 a certain negative pressure.

In the adjacent hardening station 50, the receiving mandrels 12 with the workpieces 5 are swiveled back again from the horizontal second working position into the vertical first working position, which in FIG Fig. 3 schematically illustrated by the position of the receiving mandrels 12 '. In the curing station 50, a sleeve-shaped protective gas bell 52 is arranged with a hexagonal cross-section. The protective gas bell 52 has a closed ceiling area and a lower open access opening 53. Along at least one outer wall of the protective gas bell 52, an elongated irradiation device 54 is arranged with a UV radiator. For receiving the vertical mandrels 12 with the workpieces 5, the protective gas bell 52 is moved to an upper feed position, in which the vertical mandrel 12 can be placed under the protective gas bell 52. Subsequently the inert gas bell 52 is moved via a lateral lifting device 56 with a positioning cylinder vertically downwards into a hardening position. In this hardening position of the vertically pivoted mandrel 12 is arranged with the workpieces 5 approximately parallel to the elongate irradiation device 54. By a rotary motor not shown on the holding unit 26 of the mandrel 12 is rotated with the workpieces 5 similar to a spindle, so that a total of a total irradiation of the workpieces 5 with the UV light of the irradiation device 54 is achieved. Also in the other processing stations and in particular in the coating station 40, the receiving mandrels 12 can be rotated with the workpieces 5 via the rotary motor on the holding unit 26 in order to achieve full processing, in particular painting.

The interior of the protective gas bell 52 is filled with a protective gas, in particular nitrogen. When the inert gas bell 52 is moved from the upper feed position to the lower hardened position, the enclosed protective gas atmosphere displaces the ambient air around the workpieces 5 downwards. Via a supply, not shown, in the ceiling area can regularly new inert gas are introduced into the protective gas bell 52 to compensate for the unavoidable in operation protective gas losses through the lower inlet opening 53.

After hardening of the coating of the workpieces 5, the protective gas bell 52 is again moved upwards, so that then the receiving mandrel 12 is conveyed with the workpieces 5 in the vertical position by a vertical passage slot in the housing 14 to the external removal station 70. From there, the receiving mandrel 12 can be solved with the workpieces 5 of the holding unit 26 and passed manually to a discharge device.

Claims (11)

1. Coating system for coating workpieces (5), with

   - at least one receiving mandrel (12) for receiving at least one workpiece (5),

   - a conveying means (20), with which the at least one receiving mandrel (12) can be conveyed to processing stations,

   - a painting station (40), in which the at least one workpiece (5) on the receiving mandrel (12) is coated with a paint, and

   - a curing station (50), in which the at least one workpiece (5) on the receiving mandrel (12) can be irradiated in an inert gas atmosphere by means of a radiation means (54), whereby the paint is cured,

   characterized in that

   - the receiving mandrel (12) can be pivoted between a horizontal first working position and a vertical second working position,

   - the receiving mandrel (12) with the at least one workpiece (5) is pivoted in the painting station (40) into the horizontal first working position and

   - in that the receiving mandrel (12) with the at least one workpiece (5) is pivoted in the curing station (50) into the vertical second working position.
2. Coating system according to claim 1,
   characterized in that

   - the curing station (50) has an inert gas chamber which comprises an inert gas bell (52) with a lower access opening (53).
3. Coating system according to claim 2,
   characterized in that

   - the inert gas bell (52) is vertically movable between a lower curing position, in which the receiving mandrel (12) is enclosed in the vertical second working position and an upper feed position, in which the receiving mandrel (12) can be positioned in the vertical second working position underneath the inert gas bell (52).
4. Coating system according to claim 1 or 3,
   characterized in that

   - the radiation means (54) is mounted in or on the inert gas bell (52) and is movable therewith.
5. Coating system according to any one of claims 1 to 4,
   characterized in that

   - the radiation means (54) comprises at least one UV radiator.
6. Coating system according to any one of claims 1 to 5,
   characterized in that

   - for rotation of the at least one workpiece (5) the receiving mandrel (12) is supported and driven in a rotating manner.
7. Coating system according to any one of claims 1 to 6,
   characterized in that

   - the conveying means (20) has a rotary indexing table (22), on which several receiving mandrels (12) are supported in a pivotable manner.
8. Coating system according to any one of claims 1 to 7,
   characterized in that

   - along a conveying path of the conveying means (20) further processing stations are arranged, in particular a loading station (30), a cleaning station (32), a flame treatment station (34), an ionizing station (36) and/or a removal station (70).
9. Coating system according to any one of claims 1 to 8,
   characterized in that

   - an air lock (38, 48) is arranged at least between two adjacent processing stations.
10. Coating system according to any one of claims 1 to 9,
    characterized in that

    - nitrogen is provided as inert gas.
11. Method for coating workpieces (5), in which

    - at least one workpiece (5) is arranged on a receiving mandrel (12),

    - the receiving mandrel (12) with the at least one workpiece (5) is conveyed by means of a conveying means (20) to the processing stations,

    - in a painting station (40) the at least one workpiece (5) on the receiving mandrel (12) is coated with a paint and

    - in a curing station (50) the at least one workpiece (5) on the receiving mandrel (12) is irradiated in an inert gas atmosphere by means of a radiation means (54), whereby the paint is cured,

    characterized in that

    - the receiving mandrel (12) is pivoted between a horizontal first working position and a vertical second working position,

    - for painting in the painting station (40) the receiving mandrel (12) with the at least one workpiece (5) is pivoted into the horizontal first working position and

    - in that for curing in the curing station (50) the receiving mandrel (12) with the at least one workpiece (5) is pivoted into the vertical second working position.

Images