Many different methods are known to be used in the painting cars or greater or smaller body parts or something else. A particular field concerns so-called repair treatment, which may consist of hammering, puttying, general touch-up works, clear varnish painting.
Painted vehicles or vehicle parts have to be cured and dry. A much used method consists of transferring heat, for example by convection, to the treated vehicle, or the part. It mostly comprises generating a flow having a high temperature, which is directed toward the vehicle/part. Known devices comprise a drying oven or a booth in which the vehicle/part is placed. Disadvantages of such proceedings are that they are very energy- and time-consuming. Drying and curing, respectively, may in principle occur in room temperature, but may then take up to a day. The drying procedure and the curing procedure, respectively, can be speeded up by drying in a plant as described above, at a temperature of approx. 60°, and the drying time can then be reduced to maybe between half an hour and one hour. But also this is to be considered as a very long time in the context and involves high costs because the throughput time for a vehicle or a vehicle part becomes very long and a large area is blocked.
In order to avoid the complex of problems of time and blocked area, it has become common, where possible, to carry out surface treatment of body parts or minor damage by IR irradiation to accelerate the drying. In doing so, a basecoat has first been applied, airing has been effected, after which a clear varnish has been applied, which has been allowed to dry under IR irradiation for 20-25 min. Also this involves relatively long drying/curing times.
It has also been proposed to, for particular materials, carry out the curing in two steps, a first with radiation curing by UV light, and then at a temperature of between 130°-200°, alternatively in room temperature (EP-A-0 000 407).
EP-A-0 826 431 suggests a proceeding wherein, after short drying or curing of a basecoat layer either for 3-10 min at a temperature of 40° -80° or IR drying for 3-6 min, a clear varnish layer is applied, which is dried by pulsed high-energy UV irradiation with a high-energy UV flash lamp.
Also this proceeding is time-consuming and intended for the treatment of minor damage or small parts.
It should be noted that plastic components, e.g. bumpers, may be deformed if too high temperatures are used. Plastic may be deformed at temperatures of above approx. 75°.
US 2010/0088921 discloses a device for drying a painted vehicle, which comprises panels at a workstation or a booth with IR radiation sources emitting IR radiation and having two different emission spectra, which among other things is attained by blowing a mixture of compressed air and oxygen toward a catalytic panel.
U.S. Pat. No. 4,416,068 discloses a device consisting of a repair booth to hasten drying and/or curing in connection with touching up a car. IR sources and heat radiating elements are arranged in such a way that their positions and orientation can be selected in a suitable way. In spots difficult to access, reflectors are utilized. The IR sources are arranged in horizontal or vertical groups or rows of a ceiling mounted structure moving reciprocally above the car. A uniform temperature distribution is aimed at, wherein the drying time can be reduced. However, this device does not work optimally neither what concerns speed or quality of the processing nor the working environment. In addition, the energy consumption becomes high since IR as well as heat irradiation are utilized. Another disadvantage consists of the entire plant shaking when moving along railings in the ceiling. Again another disadvantage then arises, since all painting work is highly susceptible to dust and dirt, the ceiling mounting makes that dust, etc. easily is accumulated in nooks and the like above the object, and may fall down onto the object, to an even greater extent as a fan is utilized to blow air toward the reflectors.
Generally, the curing, when using traditional clear varnish, takes approx. 30-60 min. After curing, the clear varnish is very sensitive for a couple of days and difficult to handle.
The requirements of speed and homogeneous curing and drying are particularly high what concerns the use of substances having lower content of solvent or water-based substances cured by UV light. Thus, no one of the devices known hitherto works fully satisfying neither what concerns speed, energy consumption, quality, simplicity nor environment-friendliness.
USPTO Backgrounds
USPTO Backgrounds