Coating processes – Spraying – Moving the base
Reexamination Certificate
1999-04-15
2001-02-20
Beck, Shrive (Department: 1762)
Coating processes
Spraying
Moving the base
C118S305000, C118S314000, C118S315000, C239S112000, C239S113000, C239S116000, C222S148000, C222S056000, C222S081000, C222S145200
Reexamination Certificate
active
06190739
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a lacquering apparatus or lacquering line as well as to a lacquering method, which may be effected with said apparatus, for in particular products manufactured on an industrial scale or parts thereof, such as, for example, motor vehicle bodies or parts thereof.
In the following, the invention is described using the example of the lacquering of motor vehicle bodies although it is naturally also applicable to the lacquering of industrial products such as refrigerators and other appliances.
BACKGROUND OF THE INVENTION
Series lacquering of automobiles occurs in fully automated automobile lacquering lines, with application of the colour-determining lacquer layer (as a final outer lacquer layer or as a base lacquer layer of a two-coat lacquering comprising a base lacquer layer and an outer transparent lacquer layer) being effected in a limited number of standard colours, e.g. between 5 and 15, with frequent colour changing. The colour changing arises as a result of the production schedule and generally does not occur after the lacquering of just one body, the bodies instead usually being combined into groups of identical colour. The standard colours are lacquers, which are processed in bulk and are therefore in practice fed in each case from a lacquer storage container having a filling volume of e.g. 200 to 1500 litres through a separate ring line connected thereto to the lacquer spraying elements. Automatic colour changing merely involves a switchover by a colour changer from one ring line to another ring line containing lacquer of another standard colour and the lacquer spraying elements are automatically rinsed between the end of application of the one standard colour and the start of application of the next standard colour. In the case of supply by means of ring line systems, it is customary for the lacquers in the ring lines and storage containers to be circulated in order to ensure a uniform colouring and avoid separation of the lacquer. In said case, the lacquer in the agitating and pumping mechanisms is subject to increased shear, which may lead to a loading of the lacquer. For such an eventuality, it is usually necessary to take suitable counter-measures, e.g. the addition of additives or a particular choice of binding agents.
At the special request of customers, automobile manufacturers also lacquer individual vehicles or a low number of vehicles in special non-standard colours. The number of special colours far exceeds the number of standard colours and the special colours are processed only in small quantities compared to the standard colours. The special colours may be recurring colours but are predominantly one-off colours. Since the individual lacquering of motor vehicle bodies requires only around 4 to 10 litres of the colour-determining lacquer, it is therefore uneconomic and labour-intensive to use the same lacquering procedure for special colours as for standard colours. The use, for special lacquering, of the storage containers and ring lines customary for standard lacquering would entail a considerable surplus of lacquer, which would ultimately have to be thrown away. Furthermore, the rinsing of storage container and ring line would lead to additional expenditure of effort, additional use of solvent and additional disposal problems.
In practice, therefore, motor vehicle bodies which are to be lacquered in special colours are transferred out of the normal lacquering line for series lacquering and moved to a separate lacquering cabin or lacquering line. As a rule, bodies which have been precoated, e.g. provided with a layer of primer and filler, are transferred out of the lacquering line and lacquered e.g. with the base lacquer in a special colour. Then a transparent lacquer may be applied likewise in a separate manner or the body, having been lacquered in the special colour in a separate device, is then transferred back into the lacquering line, where it is provided with the outer transparent lacquer layer and conveyed to the further conventional lacquering and stoving devices. This requires additional technical appliances outside of the conventional lacquering line as well as elaborate operations for transferring the body to be separately lacquered out of and back into the conventional lacquering line.
In “Journal für Oberflächentechnik” JOT, 9, 1996, page 28, Grau describes how it may be possible in future to dispense with the conventional lacquer supply using lacquering robots. The central feature of the new system is a magazine having a flexible number of exchangeable containers. Integrated into the magazine are devices for filling and rinsing an exchangeable container. The system automatically distinguishes between the colours of a high or low consumption probability, i.e. it distinguishes between standard and special colours. At the point of use, refilling of the colour containers of the high consumption probability is effected, while the colour containers of a low consumption probability first have to be rinsed. Depending on requirements, filling may be effected via a ring line or manually. Reference is made to the extreme suitability of the system for applying special colours on account of the possible savings on lacquer material compared with the conventional procedure of the filling of ring lines. The procedure described here however also inevitably involves handling of the lacquers by the operator, e.g. liquid lacquer has to be handled particularly during filling and emptying operations at the exchangeable containers. Furthermore, it is necessary to rinse at least the exchangeable containers for special colours. All of this constitutes not only an undesirable expenditure of effort for the operator but also entails risks of contamination, particularly in connection with rinsing and cleaning operations at the exchangeable containers. The operator is namely compelled to guarantee an adequate cleanness of the containers prior to refilling.
From DE 28 19 302 B2 a lacquering line is known, having a guide device for vehicle bodies and having spray elements, which are disposed along the guide device inside a spraying cabin and are connected by feed lines via one or more ring lines to one or more lacquer storage containers. Also described is a cleaning process for contaminated lines and spraying elements. One or more units for the individual lacquering of bodies or body parts are integrated into the apparatus. The controllable lacquer pressure regulators perform the function of colour changers connected to the spray elements.
From JP-2-280866 A in: Patent Abstracts of Japan, C-802, Vol. 15, No. 48 of 05.02.1991, a plurality of small paint containers combined into a unit are known, which are connectable by a colour changer to a spraying element.
From DE 40 13 941 A1 a small container of a vehicle body lacquering installation is known, the total filling volume of which is sufficient for lacquering one body or one part thereof.
SUMMARY OF THE INVENTION
The object of the invention is to provide an apparatus and a method, which may be effected with said apparatus, for lacquering, in particular for the individual lacquering or the series lacquering of products manufactured industrially in high numbers, e.g. preferably for the series lacquering of motor vehicles or parts thereof with lacquers. In so doing, products are to be capable of manufacture in different colours, in accordance with a colour range.
Examples are the lacquering of base layers and outer layers in standard and/or special colours. An efficient design of the apparatus as well as an efficient process control are to be made possible. Filling and emptying operations involving liquid lacquer, as well as rinsing and cleaning steps within the apparatus are to be extensively avoided.
It has been shown that said object may be achieved by the apparatus forming the subject-matter of the invention in the form of a lacquering line for lacquering industrially manufactured products in standard and/or special colours, having one or more guide devices for the industrial
Hoffer Michael
Kasulke Reiner
Beck Shrive
Herberts GmbH
Kolb Jennifer
Pillsbury Madison & Sutro LLP
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