The paint shop at the
In the paint shop,
A new separation system for paint overspray significantly reduces emissions of environmentally damaging solvents from the painting process. Moreover, the paint shop also boasts a cutting-edge energy concept, using waste heat from the neighboring biomass power plant which supplies up to 80 percent of the paint shop’s heat requirements in a carbon neutral fashion.
Prior to receiving its first paint coat, the body is subjected to an intensive preparation process. To guarantee metallic purity of the surface, lubricants, polish and other interfering substances are removed. This is followed by a phosphate coating process during which a zinc phosphate solution is applied to the sheet steel. This guarantees optimum adhesion of the corrosion protection which is subsequently applied. To prevent air bubbles from forming in cavities, resulting in uncoated areas, the body is turned by 360 degrees in the basin. In addition, the phosphate coating is consolidated during a subsequent follow-up treatment.
Electrophoretic coating is an electro-chemical process chiefly used for corrosion protection. During the coating process the body is dipped for 5 minutes into a basin, which is filled with electrophoretic dip paint and deionized water. To achieve optimal coverage of the body, it is turned around on its own axis in the basin.
For the paint to set on the vehicle body during the electro-chemical process, it must be negatively charged. The vehicle body then serves as a cathode. The dialysis cells attached to the sides of the basin function as anodes (counter electrode). If an electric current is applied to the basin, the paint settles automatically on the body because it consists of positively charged particles.
The result of the electrophoretic coating process is an especially smooth and uniform coat of paint on the metal surfaces and in the cavities. Having re-emerged from the basin, the body is dried at 175° C for 50 minutes.
The welding seams of the vehicle are sealed here with special PVC materials. While most of the steps in this sealing process are carried out by application robots, some manual work procedures remain. The underbody protection is also applied here. It consists of a material which contains PVC and chiefly protects the body from rock chip.
Now painting robots apply the filler on the inside and outside of the body. This coat of paint levels out any remaining unevennesses and possesses UV-protection characteristics. Thanks to its high elasticity, the filler protects the topcoat against damages while simultaneously boosting its brilliance. We use three different filler colors, depending on the topcoat color of the vehicle: white filler is used for bright topcoats, anthracite for dark topcoats and then we have medium grey filler for hues in between. The last step here is a 40-minute drying process during which the final cross-linking of the coats takes place at higher temperatures.
Before the bodies receive their final color, they are thoroughly cleaned and any dirt from preceding processes is removed. Only then is the coloring basecoat applied using high-speed rotating atomizers. In a fine spray of tiny color particles is given its desired hue. We use a special basecoat for metallic hues.
Yet, this paint coat alone will not produce a glossy surface. Once the carrier (water and solvents) has evaporated, the coat will turn matte. The body is now subjected to an 8-minute intermediate drying process before the clearcoat is applied just as precisely as the other coats before it. This coat is chiefly responsible for gloss and color depth and it provides perfect and reliable protection from environmental damages. To cure the topcoat, the body is put through a 35-minute drying process at 135° C.
After the drying process, the vehicle is taken back to ground level and subjected to a thorough visual inspection in the light tunnel. This tunnel is fitted with strips of LED tubes which project their light onto the car bodies. The LED tubes create a uniform strip light pattern which allows our quality inspectors to detect even the slightest imperfection in the paint. Here, we accept nothing short of immaculate: if there is the slightest flaw in the paint, the body is taken out of the line and transferred to spot repair. At this point, the raw vehicle body has been transformed into a high-gloss