Friction Stir welding question

Look at the Eclipse aviation website. They were pushing this process 4 or more years ago at the Oshkosh airshow.. Was real interesting watching a mill with a special stir welding bit "weld" two sheets of aluminum together. They had xray sheets showing no voids etc. to validate the process. At the end of each demo they would warn all us homebuilders "Don't try this at home."

I guess they're using 3 axis cnc robots with the special tooling to do the welds on all the sheet metal joints on their aircraft. Gonna be interesting in 10 years after(If?) they hit mass production to see how well it all holds up.

New processes haven't been to warmly accepted in the aircraft industry. Just look at the Grumman Tiger with it's bonded aluminum wing surfaces and see how much bad press they are given for them. I really don't know if it's well deserved.

Bart

Bart D. Hull snipped-for-privacy@inficad.com Tempe, Arizona

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Bruce W.1 wrote:

"Bart D. Hull" wrote in message news:424779ac$0$71594$ snipped-for-privacy@news.getnet.net... | | Look at the Eclipse aviation website. They were pushing this process 4 | or more years ago at the Oshkosh airshow.. Was real interesting watching | a mill with a special stir welding bit "weld" two sheets of aluminum | together. They had xray sheets showing no voids etc. to validate the | process. At the end of each demo they would warn all us homebuilders | "Don't try this at home." | | I guess they're using 3 axis cnc robots with the special tooling to do | the welds on all the sheet metal joints on their aircraft. Gonna be | interesting in 10 years after(If?) they hit mass production to see how | well it all holds up. | | New processes haven't been to warmly accepted in the aircraft industry. | Just look at the Grumman Tiger with it's bonded aluminum wing surfaces | and see how much bad press they are given for them. I really don't know | if it's well deserved. | | Bart

Boeing's got a pretty penny invested in it, and is using it on their spacecraft. I've seen some demo stuff, which is amazing! Very expensive setup, though. Obviously special applications where weld quality is critical. There is a small ridge on both sides of the weld which has to be removed. For the most exotic alloys no special filler rod is required, but you have to back up the other side of the weld from the extreme pressure, and obviously it being a heat sink it has to be carefully designed for the application. I didn't realize it at first, but there has to be a tab at the beginning and end of the weld where the probe (?) passes through. There is the probe or whatever inside the weld, spinning on through and pushing the metal around behind it, and a flat part above it to keep the pressure up and not allow the metal to flow up and out. I've used that process a number of times trying to drill titanium sheet with a regular drill bit, although it's far from my preferred process. Just press hard, go fast and let the bit burn its way through! Of course the hole isn't precision or pretty, but the engineers say it's okay. Nothing a reamer won't clean up anyway.

Friction welding in general has been around for 70 or more years. Lots of crankshafts, drive lines, automotive valves and other items are friction welded. Shrug.

Dont know about this process of course, but its not a hell of a lot different than spot welding in some ways.

Gunner

Leftwingers are like pond scum. They are green, slimy, show up where they are not wanted, and interfere with the fishing.

Strider

I started a thread on friction stir welding a couple of years ago after I saw the process in action in Navasota, Texas, at a drill pipe factory.

The factory was importing seamless tubing from Mexico, then friction stir welding the couplings onto the ends. It was quite amazing. Reminded me of the water carrying brooms in the Sorcerer's Apprentice.

The ends of each stick really glowed after the couplings went on. Then that stick was carried away on a conveyor and the next one rolled in. All automated.

Vernon

There is a difference between Friction STIR welding and friction welding. Friction welding is done by rotating one part and then pressing it against the other part.

Friction stir welding is more or less a linear system. More or less like putting two pieces of aluminum on a mill butted against each other. Then running a carbide round piece turning at high speed right down the seam. Takes a lot of horsepower. Melts a narrow area along the seam and ends up with a very small heat affected area. Take this as being from someone who has read but not even observed either process.

Dan

In that case, I stand corrected. The operation I witnessed was just as you stated. The sticks of pipe were rotated while being pressed into the nipples, which were held stationary.

Thanks!