Bonding instead of plugging in the automotive industry

19.04.2021 Every year, more than 10 billion holes in car bodies worldwide, which are necessary for the e-coat painting process, have to be closed to protect them from corrosion. Usually, this is still done by hand with bulky plugs made of plastic – an extremely time-, energy- and labour-intensive process.

An application head in action.
© Photo: tesa
An application head in action.

Each shift, the workers press more than 3500 plugs into the holes with their thumbs, often overhead. In the process, they apply a pressure equivalent to 7kg per plug – an enormous ergonomic strain. The alternative: adhesive pads from tesa, which a robot glues quickly and reliably.

Close cooperation with Porsche

Together with its long-standing supplier tesa, Porsche AG has developed an innovative robot-assisted manufacturing process at its headquarters in Zuffenhausen, Germany. The all-electric Porsche Taycan is the first vehicle in the world to use a new automation technology that optimises the hole closure and thus the entire production process. By summer 2021, Porsche AG will also implement this new concept in its paint shop at the Leipzig plant. "The cooperation with Porsche is an excellent example of how tesa, as a long-standing partner to the automotive industry, drives innovation and develops forward-looking solutions to offer our customers added value," explains Angela Cackovich, executive board member direct industries at tesa SE.

Heat-resistant, lightweight tesa adhesive pads also promote e-mobility

Compared to conventional plastic plugs, tesa adhesive pads offer a number of advantages. While plugs always have to be an exact fit, it is possible to use one pad size to overlap and seal different hole sizes. This reduces the overall complexity and saves time. Furthermore, tesa adhesive pads can offer additional benefits. The basic product tesa PunctureGuard provides corrosion protection through perfect sealing, while at the same time offering high mechanical strength and good noise-damping properties. In addition, these adhesive pads, which are only one millimetre thin but can withstand extreme loads and last the life of a car, are considerably lighter than the plugs, which are around six millimetres thick. This is highly relevant for e-cars, because every gramme more means a loss in range. The special product tesa FireGuard, developed for the so-called Battery Foot Print, withstands flames of up to 500 degrees Celsius for six minutes and protects the passenger compartment so that drivers and passengers can leave the vehicle if a defective battery catches fire.

Flexibility and speed thanks to robot technology

"Our automatic application unit, tesa EfficienSeal, was developed with tesa expertise and guarantees the customer that holes are effectively sealed," explains David Caro, corporate vice president of tesa's Automotive Business Unit. "Positioning accuracy is also significantly higher compared to the manual process: 100 percent sealing in half the time."

The use of the innovative automation technology provides tesa's customers in the automotive industry with a high degree of flexibility: Depending on the type of vehicle – and the associated number and size of holes in the body – the robot can bond different pads as needed by quickly changing the application heads.