Step by Step through ŠKODA’s State-of-the-art Paint Shop

First of all, the body enters the pretreatment line. This is where it is degreased and where dust and other impurities are removed.

The body is also washed in warm water as it passes through 60-degree baths. Between each bath of cleaning liquids, jets spray water in much the same way as you would see in a normal car wash. In the baths, the body is rotated roof downwards to be sure that the liquids get into every nook and cranny. The doors even have special holders to keep them ajar, allowing the liquid to reach their inner edges. The rotation feature is one of the advantages of this new line and is not found in every paint shop. The pretreatment line includes phosphating so that the paint system subsequently adheres more firmly to the metal.

The body passes through 60 °C baths, where it is rotated roof downwards to be sure that all parts are immersed in the liquids.

Next up is the cataphoretic coating. It probably sounds like a disease, but it is actually a process in which anti-corrosive paint is applied to all surfaces of the bodywork. Technically speaking, this is surface precipitation. At this stage, an electric current passes through the body, forcing the paint to precipitate evenly on its surface. Whatever the colour of the finished car, the body is always grey when it emerges from the cataphoretic bath. The cataphoretic coating tank looks a bit like a wild river. A constant flow of liquid can be seen on the surface because the paint needs to be constantly mixed to prevent it from settling on the bottom. Here, too, the body is rotated in liquid so that the paint reaches all parts. The entire paint line can be custom-programmed for any model. As a result, each body can submerge or emerge at the angle best suited to its shape.

Cataphoretic coating (KTL) line – in the cataphoretic bath, anti-corrosive paint is applied to all surfaces of the bodywork. Technically speaking, this is “surface precipitation”.

The deposited paint takes on its unique anti-corrosion properties in an oven, where it is baked (“netted”) at 180 °C for 56 minutes. The baking process also cures all adhesives used in the welding shop. Now the cataphoretic coating has been netted, the body undergoes its first visual check with the human eye. Workers identify minor flaws and remove them manually with their tools.

After its cataphoretic coating, the body undergoes its first visual check with the human eye. Workers fix any minor flaws manually with their tools.

The next stage involves various caps and plugs. Openings are plugged and covered to keep out the protective spray, as this would cause problems further on in the production process. Some covers are later removed as they are at points important for further assembly line work (e.g. the installation of shock absorbers). 

Openings are plugged and covered to keep out the protective spray further on in the painting process.

A robot then applies a protective spray of sealant, known as plastisol, to the plugged chassis.

Protective spray (plastisol) is applied to the chassis.

Explore the new paint shop in the latest episode of our series "My Machine:".

https://www.youtube.com/watch?v=G0D9tM7exAM

Further down the line, robots apply various types of plastisol, which is used, for example, to seal joints in the engine and luggage compartments and to protect the body from stone chips. Once robots have done their bit, it’s time for humans to finish applying the sealant in places a robot finds hard to reach. For example, in the area where the rear lights are to be fitted, the plastisol needs to be  applied and then spread to create a layer that is neither too thin for insulation nor so thick that the rear lamp won’t to fit into the space after the plastisol has hardened.

Robots apply different types of plastisol in order to seal the joints and protect the bodywork.

Now it is time for what most people imagine painting to be. A frame with a tank cap is hung on one door and the brushes clean the body before it enters the filler line.

The body is cleaned with brushes before entering the filler line.

It is here that the primer, or filler, is applied. There are four possible shades, chosen according to the colour of the subsequent top paint. The primer may be white, black, grey or red.

Filler line – it is here that the primer, or filler, is applied to the body.

After this spraying, another dryer awaits the body, this time a large hot-air oven, where the paint is dried and the plastisol cured at 160 degrees centigrade for about 40 minutes.

The dryer takes the form of a large hot-air oven – the paint is dried and the plastisol cured at a temperature of 160 °C.

When it comes out of the oven, the car is taken over by the filler sanding station, which checks and fixes and minor flaws.

Filler sanding stage – workers inspect and fix minor flaws.

This is the point where the ostrich feathers we mentioned in the introduction make their entrance. On rollers that revolve around the body just like the wash rollers in a car wash, they remove even the finest dirt or dust particles. The paint shop workers agree that we have yet to find a better material. Thorough cleaning to get rid of even the smallest dirt particles is essential because it is now that the body gets its coloured coat.

Ostrich feathers on rollers thoroughly cleanse the body, removing the finest dirt and dust particles. The cleaning process is similar to a car wash.

The line guides the body into a realm of painting robots, which spray on one coat of paint, or two coats if the finished car is to be metallic.

Robots apply one coat of coloured paint (or two coats if it is metallic).

After a brief stay in the intermediate oven (a quarter-hour “sauna” at 85 degrees centigrade), another painting robot comes into play. This time it applies a topcoat, which is clear and gives the entire surface shine, hardness and protection from minor scratches and stone chips.

Another paint robot applies the clear topcoat and varnish to the body. This gives the surface shine, hardness and protection.

At this stage of the body’s journey, there is an interlude of roughly 50 minutes, as it has entered another oven where the air flows at 140 degrees centigrade. The ovens in the new paint shop in Mladá Boleslav are the first of their kind in the world. One factor making them unique is that the body does not travel head first, but sideways. More importantly, the hot air in them flows into the body via the engine compartment and windscreen. As a result, the paint dries in the direction away from the sheet metal, not from the top layer down. The same principle is used to dry the cataphoretic coating and filler. All of this has also made it possible to shorten the length of the drying line to around 100 metres (other ovens are twice as long).

This unique oven, the first of its kind in the world, supplies 140 °C air flow. The body travels sideways and hot air flows into it through the engine compartment and windscreen to ensure more effective drying of the paint away from the sheet metal.

Before the body, now in all its coats of paint, leaves the paint shop, it goes from the oven to the finishing line. Here, again, workers with eagle eyes and nimble hands look for the slightest flaws on the paint, and, if they find them, correct them. When we talk about paintwork flaws, we don’t mean scratches or paint-less spots, but really minute details that the untrained eye would not even notice. Almost all imperfections can be corrected by fine grinding and polishing. When everything is all right, the body, coated with shining paint, heads for final assembly, where it is turned into a finished car.

Finishing line – workers remove minor imperfections that the untrained eye does not even notice by fine grinding and polishing.