Adhering Instead of Plugging


Hole covering, or closing holes in the vehicle body, is a major topic in the automotive industry. That’s because there are up to 220 holes in a single body that must be covered during the automotive manufacturing process. That’s about 10 billion holes per year. tesa is solving the complex issue of hole covering intelligently with its core competence: adhesive tape solutions that adhere reliably throughout the vehicle’s lifetime and at the same time are much easier and faster to process than conventional plugs – even by robots in the future.

Text Johanna Schörck, Christina Zucker-Henkel

But why does a car body have so many holes? There are various reasons. For example, there are threaded and drilled holes that must be permanently or temporarily closed. Other openings allow hard-to-reach components to be assembled, serve transport purposes, or are required in the dip coating process so that the coating can flow in everywhere and back out again, thereby ensuring complete corrosion protection.

Offering adhesive solutions for your hole covering application in the car manufacture
Up to 220 holes per car body – Most of them must be filled in during the production process.

However, in order to prevent moisture or dirt from penetrating into the car body cavities during its use phase and to reduce air turbulence noise while the car is moving, the openings must of course be resealed. This is often still done with plugs made of plastic, rubber or metal, a process that requires a great deal of time, work and personnel, because the holes have different sizes and shapes. In order for the plug to fulfill its purpose, it must fit precisely and be pressed into the correct opening with sufficient force.

Advantages That Stick

With its hole covering product range, tesa has created an alternative: pre-fabricated die cuts in various sizes and in various adhesive tape designs that offer decisive advantages over conventional plugs. While the plugs must fit exactly, it is possible to close different sized holes with one size of stamped part. This reduces complexity and saves time.

Automotive Hole Covering
Prefabricated die cuts instead of plugs – The adhesive points are easy to remove from the base and stick to the holes.
"We specialize in tailoring the shapes, sizes and characteristics of our products to our customers’ needs."
Alexander Knittler

Product Management tesa Automotive

Also, applying the die cuts is much easier than pressing plugs into holes. That saves work. Another advantage is the adhesive points are many times lighter than plugs. That saves weight, an essential requirement of the automotive industry when it comes to fuel savings in gasoline engines, or range in electric vehicles. In addition, the adhesive tape solutions can offer different added benefits like impermeability, heat resistance, noise reduction and puncture resistance.

About 1 billion holes

are now closed with tesa® die cuts each year.

Manual hole covering in the production line
Manual work on the production line – Until now, the adhesive die cuts had to be applied manually or in a partially automated manner
Scale Illustration
Scale Illustration

True lightsweights compared to plugs

In the automotive industry, efficiency is the name of the game. The reduction of weight in vehicles has become not just an obligation but an attitude. Every gram counts for the designers. The tesa® adhesive tape solutions are up to 85% lighter than traditional plugs.

Designing the Future With Adhesive Tape Solutions

And tesa takes it a step further. Despite die cuts being easier to use, closing the holes is an ergonomic challenge for production employees. Some holes are in hard-to-reach places. This requires the employees to work in uncomfortable and sometimes unhealthy positions during processing. tesa has developed a solution for this in collaboration with technology partners: a robotic head that can apply the die cuts in a fully automated way, and therefore faster. Incidentally, this too is a decisive competitive advantage for die cuts compared to plugs, which make automated insertion practically impossible, or allow only partial automation, due to their prefabricated shapes and differing hole contours.

Robotic Hole cutting Maschine
Simplification in the production line – The robotic head applies the die cuts in a fully automated and highly precise way.
"Our hole coverage robot is a successful example of the way tesa is shaping the future of adhesive technology."
Dr. Norman Goldberg

Executive Board Direct Industries, tesa SE