Czech-based carmaker Skoda Auto has a new paint shop that it says is Europe's most modern and among the most environmentally friendly. As Hardy Graupner reports, technology from southern Germany plays a crucial part.
The first thing you'll likely notice when you look at a car in the street or in a showroom is its color. It's also the last thing you see when you hop out of a car. Some studies suggest that for many people, color is the most important factor when it comes to deciding which vehicle to buy — more so than even the engine.
The art of vehicle-related coating on an industrial scale started in the early 1900s when varnish was brushed onto the surface of car bodies. When the varnish was dry, it was sanded smooth and polished many times over, but the whole process could take well over a month to complete for a single car.
Since then, paint shops have come a long way in enhancing gloss and the depth of color parameters. But they've also made astonishing strides in lessening the impact on the environment.
The seven-story paint shop is actually the carmaker's tallest building at its huge head location some 60 kilometers (37 miles) away from Prague and boasts an area equivalent to three soccer fields.
Facing growing demand for its car models, Skoda Auto urgently needed the new paint shop to remove a production bottleneck. The new facility will see the carmaker eventually increase the capacity by 168,000 painted bodies to reach a total of 812,000 cars per year. Investments of over €214 million ($238 million) have made this possible — money that was also pumped into more environmentally friendly production methods.
This is where southern German mechanical and plant engineering company Dürr comes in. It supplied the technology for the Skoda Auto paint shop as it appeared to fit perfectly into the carmaker's GreenFactory program, part of its GreenFuture corporate policy that aims to halve the impact of vehicle production on the environment by 2025, compared with 2010 levels.
Reducing energy consumption
Dirk Gorges, senior vice president of Sales at Dürr, told DW that lower power requirements were one of the top benefits.
"When you ran a big paint shop in the old days, your energy demand would have resembled that of a town of 40,000 inhabitants," Gorges told DW. "With our system in place, energy requirements are reduced by a whopping 60%."
Dürr is the world's largest paint shop builder worldwide, reaching annual revenues of €2 billion in the sector. Business has been particularly brisk in Asia and China in particular. In line with a rough estimate, every second car globally gets painted with the help of Dürr technology.
Skoda Auto was eager to profit from the company's unique know-how and sustainable systems, the automaker's board member for production and logistics, Michael Oeljeklaus, told DW.
"Sustainability has been a top priority at Skoda Auto, and we take a close look at our CO2 footprint," Oeljeklaus told DW. "The air in our paint booths from Dürr is recirculated to a large extent, so little new air has to be brought in from the outside — the reuse of the filtered air saves an incredible amount of electricity."
Reduced energy consumption is also in focus when it comes to drying the paint layers. "For the first time, a new dryer technology has been installed, heating up the metal of the car bodies uniformly from the inside out with a central recuperator design that reduces operating energy by 25%," Dürr's Dirk Gorges added.
Watching paint dry can be interesting after all
Although paint cycles on the ground involve five layers, their overall thickness only amounts to around 100 micrometers, Gorges pointed out — that's only twice the breadth of a human hair.
"Our robots create a very fine paint spray that settles on the bodywork," Gorges said. "We're talking about extremely thin layers of paint, meaning that we use as little material as possible. This in turn leads to very small amounts of residues. Also, if we need to switch from one color to another, interaction of the components on the robot arms ensures that little gets wasted."
Reducing the amount of hazardous solvents used for the paints has been an additional benefit of the technology in place. But Skoda Auto's Michael Oeljeklaus conceded that getting rid of solvents altogether wasn't possible for a very obvious reason.
"The base coat is water-soluble; there are no solvents required," he said. "However, you need a certain amount of solvents for the outer layer of paint, the clear coat — otherwise you would run into problems with your car if it starts raining."
How to bind unused particles?
Oeljeklaus mentioned that Dürr's technology enabled Skoda Auto to embark on totally new ways of getting rid of unused paint particles filtered out from the air in the spray booths.
These particles — so-called overspray that doesn't find its way onto the car body despite the precise work of robots — used to be captured in a water bath, but that is no longer the case in Skoda Auto's new paint shop, Oeljeklaus emphasized.
"Overspray is no longer bound by water here, we use limestone powder instead to absorb the paint particles in the air," he said. "The limestone powder waste then gets burned in the company's own power station together with biomass for required desulfurization, or acid neutralization. It means that the powder gets burned at 1,300 degrees Centigrade leaving no residues behind. So we have to buy 40% less of the stuff that we would have to buy anyway for acid neutralization in the plant."
The carmaker has created an additional 650 jobs in Mlada Boleslav which will also see the production of electric cars as of next year. The paint shop is run in a 24-hour operation, meaning that over 200 people are always on the ground per shift. They're mainly busy with controlling tasks, material staging, surface preparation, maintenance or logistics.