Dow Automotive Systems' BETAFORCE adhesives, shown here joining carbon fiber composite automotive panels, are two-component polyurethane bonding systems designed to join carbon composites to each other or to materials such as aluminum in vehicle bodies. (Source: Dow Automotive Systems)
Fascinating story, Ann, on how to join materials that can't be welded. One thing that gives me pause is that as they develop appropriate adhesives, it will still only be a guess on how the joining materials will hold up after 20 years. Only time will tell whether the adhesives will hold the car together over decades.
These are structural adhesives, and many of them are being adapted from aerospace applications, where they've been used with composites for some time. We covered structural adhesives here http://www.designnews.com/document.asp?doc_id=237011
I did some work at Raytheon (Beech) quite a number of years back. They routinely used adhesives to bond aluminum aircraft parts together. The parts were also riveted (sparingly), but the engineers referred to the rivets as "chicken rivets", because they insisted the glue was more than strong enough. Supposedly the FAA wouldn't let them get rid of all of the rivets. I don't know how it ages, however. We had to disassemble some of the parts that were glued, and the aluminum would tear before the glue would let go. As I remember it, the stuff was basically inseparable.
That's very encouraging, Ttemple. Was that a number of years ago? I would guess if adhesives had any durability problems we would know by now. In manufacturing, I would think using adhesives is more efficient than welding.
I would say around 1996 or so. They were manufacturing the (Kingair?)"1900D" heavily at that time. It says on wikipedia that the 1900D was introduced in 1991, and produced through 2002. I'm sure that many 1900D's are still in use as regional commuters.
I don't know when they started using adhesives though. The part I remember specifically was the window attachment to the fuselage skin. There was sort of an aluminum porthole looking piece that was glued to the fuselage. The joint had the appearance of a weld, and it held together like it.
I think they use adhesives in the wing compartments too, at least in the areas where there is going to be fuel stored. The adhesives seal the compartments, I think. They also use special fuel resistant coatings on the skin inside those areas.
ttemple, thanks for telling us about your direct experience. Anything going into the construction of commercial aircraft has very strict specifications and requirements, including extensive testing on the ground and in the air, and everything is 100% traceable. Whether structural adhesives or fasteners are used in a particular part of the plane depends on several factors, but stresses in aircraft are much more extreme than in cars.
Ttemple, it sounds like there is an good long track record on the adhesives, at least a couple decades. So, while these adhesives may be new to the auto industry, they seem to be well tested in aerospace.
It certainly is a valid question, adhesive lifetime, and how does one speed the aging process so as to find a correct answer? And the very important question is how reliableare the bond lifetime results? Many adhesives primarily fail through long term creep type of fault, while in others t6he ridgid bond becomes brittle and does not stand up to shocks. Two different failure mechanisms, it seems. And he experience of how things stick to a composit is not the level that we are looking for. So the solution is to understand the failure mechanism, and use that information.
A lot of research has been done on structural adhesives, as we've covered here http://www.designnews.com/document.asp?doc_id=237011 and here http://www.designnews.com/document.asp?doc_id=236816 Fabrico, which doesn't make adhesives, but uses them assembling all kinds of structural components, has articles and a Q&A on many of these subjects here http://fabricoforum.com/2012/06/structural-adhesives/
BMW has already incorporated more than 10,000 3D-printed parts in the Rolls-Royce Phantom and intends to expand the use of 3D printing in its cars even more in the future. Meanwhile, Daimler has started using additive manufacturing for producing spare parts in Mercedes-Benz Trucks.
SABIC's lightweighting polycarbonate glazing materials have appeared for the first time in a production car: the rear quarter window of Toyota's special edition 86 GRMN sports car, where they're saving 50% of its weight compared to conventional glass.
Design engineers play a big role in selecting both suppliers and materials for their designs. Our most recent Design News Materials Survey says they continue to be highly involved, in some ways even more than the last time we asked to peek inside their cubicles.
Daihatsu is one of the first carmakers to customize car exteriors using 3D printing's mass customization capabilities. Effect Skins -- small exterior bumper and fender panels in different colors and textures -- can be ordered for its Copen convertible.
Several new products in this group of new adhesives, coatings, and sealants are formulated to protect sensitive electronic components, or to seal components of commercial and military aircraft. Others are designed to operate in tough, messy, dirty oil & gas operations, or for rotary applications and motors.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies.
You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived.
So if you can't attend live, attend at your convenience.