25th June 2013
News agency Reuters has reported on the increased use of adhesives in the automotive market as car makers look for ways to save weight from their vehicles. We’ve taken a few highlights from the article below but we’d recommend heading over to Reuters to read the full story.
As well as sealants that fill in tiny gaps in the various joints of a car, stronger structural adhesives can now be used to hold together and stiffen load-bearing parts and components like doors, bumpers and struts.
Audi’s $147,700 top-of-the-line R8, for example, is in large part fastened by advanced structural adhesives which have also been developed to withstand racetrack vibrations and fierce heat.
“We don’t buy glues off the peg but work very closely together with manufacturers on complex specific adhesive applications,” said Michael Zuern, head of materials engineering at Mercedes-Benz at Mercedes-Benz.
Sweden’s Atlas Copco entered the auto adhesives segment in 2011 through the acquisition of German company SCA-Schucker.
“It’s one of the product areas with the strongest growth since it’s driven by new techniques all the time, and the car makers’ new ideas,” said Mats Rahmstrom, head of the group’s business area Industrial Technique.
“Adding power makes you faster on the straights, subtracting weight makes you faster everywhere,” Colin Chapman, founder of Lotus cars, used to say.
But whereas it was once the preserve of race cars, lightweight is becoming more mainstream. Producers like Alcoa expect to more than triple sales of aluminium sheet to carmakers by 2015 as they opt for that over steel for doors, bumpers and cylinder heads.
Bernd Mlekusch, head of technology development at Audi, said the proliferation of lightweight composites may cause the amount of glue used in an Audi vehicle, which is often illustrated by carmakers in the total length of bonding substance used rather than weight, to swell to a length of 150 metres in coming years from 100 metres currently.
Because adhesive bonding increases the stiffness of the body shell, the vehicle can better absorb bumps and in-car noise is dampened, Mercedes’ Zuern told Reuters. It also makes for better handling and helps absorb the impact of a crash.
GM’s new CTS sedan uses 118 metres of structural adhesives, more than the length of a soccer field, helping to make the vehicle 40 percent stiffer than its predecessor.
Using aluminium for the doors of the CTS shaves 25 kg off the weight of the car, GM said.
Andrew Christie, a product manager at PPG’s engineered material solutions division in Germany, said there were fracture-toughened adhesives on the market which could absorb the energy of an impact far more efficiently than standard adhesives or even spot welds.
“One of the key things to surviving a crash is that the structure should absorb the impact and not you or I,” he said.
Still, adhesives aren’t without flaws.
In 2010, Fiat’s Ferrari brand recalled 1,248 458 Italia supercar models after determining that a special adhesive used to attach a heat shield inside the wheel-arch was prone to melting and had caused several cars to burst into flames.
Ferrari subsequently replaced the glued sections of the heat-shield with metal rivets.
Carmakers and adhesive suppliers work with research institutes like Fraunhofer in Germany to see how they can cure glues at lower temperatures and make sure they can be dispensed accurately by robots.
“Initially, automakers didn’t have the courage to admit that certain parts and sectors of the car require bonding. That’s well and truly over now,” said Manfred Peschka, an expert on adhesives at Fraunhofer’s facility in Bremen.