Page 54 - Australasian Paint & Panel Magazine Sep-Oct 2018

TECH TALK AUDI
CREATING
REPAIR
METHODS
Sam Street met with some of the Audi engineering team that creates the repair methods bodyshops need to employ to restore their cars to pre-accident condition.
LOOKING AT SOME of the repair methods for various cars from different manufacturers I’ve often wondered at what stage these were developed – or were they just an afterthought? After my factory visit seeing robots performing their precision welding,
I was fortunate enough to find out exactly how the engineers at Audi prepare methods for humans to repair what the robots have built. Charles Adou, Service Technic, explains that it’s his team that
decides which materials will be used in a new model long before a pen is even put to paper in the design studio. This conjured visions of designers tossing their metaphorical ponytails around when they couldn’t have the shape they first wanted. “It’s a fight – we have to accept some design features and, of course, the customer has to like the design. However, the designers must also accept our directions
– we need so many millimeters of material here for the car to deform safely in a crash etc– so you work together and in the end you find a solution that satisfies everyone, especially the customer. Getting all this agreed at the beginning of the design is essential. If we need something that can be repaired in a certain way, we have to be in on the ground floor, because later on in the design process it’s too late.”
If it’s a material that they haven’t used before in production such as carbon fibre, which is now employed on the R8 and A8, then a huge amount of research gets underway.
“Carbon fibre reinforced plastic (CFRP) was a new material for us. First of all we researched the aeronautical and Formula 1 industries and talked to their engineers to see what was possible.”
When looking at using new materials the Audi engineers order in samples and work closely with the manufactures of these materials, experimenting on their samples. For instance there are many benefits to aluminium die cast parts but they are large and it’s difficult to punch rivet them without causing cracking because of the ductility of the metal.
“We start working with these samples and trying things out, for instance can we weld it? What are the difficulties?”
Once the construction materials have been decided the engineers must develop the right methods and tools to repair them. The challenge is how to develop a repair that will essentially recreate the same car that came off the production line.
“With CFRP, for example, we started out testing the bonding and coating processes. We realised that we need to coat CFRP parts because it isn’t possible to repair scratches or just paint over the coating without risking some bubbling.”
Joining technology is obviously a vital step in the repair process. “We have to check what is possible. Friction-element welding is relatively new (a quickly rotating steel rivet passes through an aluminum sheet under high pressure and forms a firm
54 PAINT&PANEL September / October 2018
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