They not only look beautiful, they also perform a unique task. Painting wire springs in color is the most effective technique for avoiding mistakes caused by confusion. Drum coating with the special "Epital" coating systems is the standardized solution from Rotover Lackiertechnik in Wuppertal.
There is no question about it: process reliability in the use of technical springs is crucial in order to be able to exclude serious consequential errors. Difficult, technically highly sophisticated springs protect, for example, electronic safety switches and emergency functions in numerous components of everyday life. An unintentionally mixed-up leg spring in a residual current circuit breaker can lead to elementary, or even fatal accidents. What the human eye can only distinguish with difficulty, nevertheless has vital differences. This must be effectively avoided. And this from production to storage and use.
The colored painting of technical springs is by far the most effective means of reliably distinguishing similar spring types visually. Put the blue spring in the left door, the green spring in the right. What sounds so simple is similar to the error-avoiding principle of Poka Yoke.
Many manufacturers and users of technical springs choose the tried-and-tested "Epital 2K HT" coating as a suitable measure for reducing the probability of possible faults occurring when assessing the risks of their processes (standard requirement of IATF 16949 and DIN ISO 9001:2015). After all, if the human eye cannot otherwise distinguish similar nibs in a process-safe manner, such a color-coding system takes over the assignment function.
Epital 2K HT coatings are a special two-component coating system developed for the bulk coating of small mass-produced parts. This paint system is used by Rotover for the painting of technical springs. Rotover Lackiertechnik GmbH, founded back in 1992, specializes in the contract painting of bulk small parts. Everything that is small and has to be painted or coated in bulk is the hobbyhorse of the specialist from Wuppertal. The application is carried out in the so-called hot drum coating process, in which springs or other small parts are finely atomized in a heatable drum coating system using the Epital coating system.
With these special Epital 2K HT paint systems, Rotover thus complies with Siemens standard SN 68051, among others. Rotover's advantage is that the special Epital paint qualities originate from its sister company Hülsemann Coatings GmbH and therefore paint development and paint application can in principle be offered from a single source. Hülsemann's Epital coating systems are particularly known for their high color variety, thin coating layers and elastic, very good adhesion to cold-formed wire springs. In combination with Rotover's sophisticated coating process, important advantages are offered for wire and bending springs. Even springs just a few millimeters in size can be coated all around without the threads sticking or the springs being damaged.
With the Epital 2K HT coating system, a complete color coding program is available. In addition to pure uni color shades, the metallic effect variants are recommended, for example, in blue, yellow, green, red or violet metallic. Numerous intermediate shades are available. The metallic effects are applied very thinly with dry film thicknesses of 2 µm to 4 µm and have a strong visual impact due to their metallic brilliance.
The Epital 2K HT coating systems can be applied to different base materials. Adhesion to alloyed wire and stainless steels is given. Most galvanically treated surfaces can also be painted with this paint system. In principle, the base material must always be clean and free of grease. Overpaintability is also possible on inorganic zinc flake coatings.
Other properties of the Epital 2K HT paint coating include:
- Good adhesion of the coating, even under continuous load.
- Non-affection of the mechanical spring properties.
- Sufficient climatic resistance of the coating.
- No physiological adverse effects, e.g. in case of skin contact with the coating.
- No risk of hydrogen embrittlement.
- No corrosion-causing components that have a negative effect on the springs or the environment.
Coating and drying in one process
The technical springs are coated at Rotover using the special hot-barell painting process. In this process, the springs are fed as bulk material to modern coating drums. At rotational speeds of between 8 and 14 revolutions per minute, the springs are then gently agitated. At the same time, the Epital 2K HT coating system is finely atomized by automatic spray guns and applied to the springs. During the painting process, filtered, preheated air is introduced into the spray drum. It heats the springs to the temperature that is matched to the material, the geometry and type of springs, and the paint system. Temperatures of 30 °C to 90 °C are usually set here. The object temperature of the springs is permanently measured and controlled by an infrared sensor. In this way, the Epital 2K HT coating system bonds intensively with the base material and dries even during processing. At the end of this batch process, the springs are ready for packaging.
For new springs, Rotover first performs test runs and determines process parameters such as drum size, speed and inclination, coating quantity and spray pattern, as well as the optimum part quantity per batch.
Rotover's painting process allows a large quantity of springs to be painted in a single pass. This also makes the Rotover drum coating process the most economical application process for cold-formed wire springs.
Thanks to the many years of experience of the family-run contract coater Rotover Lackiertechnik, even technically difficult types of springs, such as anchor springs or open torsion springs, can be coated without tangling or deformation. In addition to Epital color coating, functional slide coatings or zinc flake coatings can also be applied. Coating technical wire springs is one of Rotover's core competencies. For this reason, the company is also an associate member of the German Spring Industry Association.
Rotover Lackiertechnik GmbH
Essener Straße 60
D- 42327 Wuppertal
Tel.: +49 202 271640
info@rotover.de
www.rotover.com