Friction Stir Welding at EWI
By James Cruz on Wednesday, October 31st, 2012
My name is James Cruz, and I’m an engineering manager here at EWI. One of the groups which I’m extremely fortunate to manage is a technology group called Friction Stir Welding (FSW). I can’t tell you the thrill I felt when I read my buddy Eric’s Facebook page last week and his status update read:
“Wow, friction stir welding in the news today! I realize that only about 3 of you will appreciate the excitement, although a larger number will benefit. Such is the life of an engineer. :)”
Eric is an old college buddy of mine, and a fellow graduate of the OSU Welding Engineering department. We keep in contact mostly through Facebook now, and I am almost positive Eric had no idea that FSW was one of the groups under my purview. He is, however, a fan new technology (especially welding applications), so naturally he keeps his eyes peeled whenever a welding technology makes the news!
The recent buzz about the use in FSW in mass production applications gives me a platform (and hopefully a little Google momentum to help you find this blog) to talk about the FSW process in general, and get a bit more specific about what role EWI plays in developing it. Let me start by offering a layman’s definition to what FSW is…
Autumn is quickly giving way to winter, but you haven’t quite gotten accustomed to carrying your mittens to keep your hands warm and cozy. You’re hanging out waiting for the subway, maybe navigating around your “Smarty Pants Phone” (my daughter’s term for smart phones), and realize your hands are freezing. What do you do? You could blow on them – the warm air from your breath feels good. But then your hands are all wet from the condensation of your breath – so that makes them even colder! Wait – then you rub them together. The faster you rub them, the warmer they get. Ahh… Much better. That, my friend, is frictional heating – the concept behind FSW.
In the FSW process, there is a rotating pin tool (think drill bit) that spins and is brought into contact with the two pieces you want to join. The speed of rotation depends largely on the materials you’re trying to join, but can range from a couple of hundred revolutions per minute to several thousands of revolutions per minute. The friction between the pin tool and the pieces you want to weld generates heat, a little more than you generate when rubbing your hands together – but the exact same concept, and brings the materials to a temperature around 70% – 80% of their melting temperature. The materials are then, quite literally, stirred together.
EWI has had an active role in the development of the FSW process since very early in its life. In addition to holding numerous patents related to friction stir welding tools and materials, EWI has been a key contributor in advancing many of our customer’s FSW goals. One of the most recent examples is work on joining conductors for the Princeton Plasma Physics Laboratory fusion reactor. How cool is that?! There are a whole host of great examples of FSW work at EWI related to defense applications. Naturally, there are more examples we would love to be able to share, but our commitment to maintaining our customer’s confidence in our confidentiality prohibits that.
What I do want you to take away from this blog, though, is that the FSW process is poised for a breakout year. Previously relegated to niche applications like the Space Shuttle, the technology is moving to much more mainstream and high production applications like aerospace, automotive, and yes – even the consumer electronics market.
As a parting shot, my now semi-famous CFO has thrown down the gauntlet… If this humble blog receives more hits than one of his between now and November, he’s buying me lunch. I’m sure it will only be McD’s, but anything that causes him to break cash any amount of out of his pocket is, well, reward enough for me! Plus, isn’t it about McRib time?