Friction Welding

[woodlandfarms]

Kinda cool
Seeing Friction Welding in Slow Motion Is Like Watching Stars Form

 

[SPYDERLK]

Iv done it on a lathe between aluminum and stainless steel 5/8" rod. Strong enuf to beat on a concrete floor. Finally broke it using a hammer. Some aluminum stayed on the SS.

 

[flusher]

Friction stir welding was introduced in the mid 1990s in the aerospace industry and is now the go-to welding method for aluminum alloy propellant tanks for modern launch vehicles like the SpaceX Falcon 9. It's used also on the tanks for NASA's Space Launch System (SLS, aka the Senate Launch System). Makes a lot better welds in aluminum alloy than heliarc, which was the method used since the start of the space program.

 

[npalen]

Patent US3597832 - Inertia welding of steel to aluminum - Google Patents
Caterpillar was one of the pioneers in friction welding.

Friction welding - Wikipedia, the free encyclopedia
It apparently originated in Russia back in the 50's.

 

[yomax4]

ESAB used to sell Stir Welding systems Way Back when they actually built something. I watched it in action at Fab-Tech several years in a row. I still have a few of the aluminum coupons that were stir welded together. Cool process but cost prohibitive in anything but aerospace or bazillion dollar projects. There are a bunch of vids out there on this.

 

[DXN1EL]

 

[LD1]

I have watched alot of those videos before.

One thing that disappoints me, is I assume all of them videos are just for demonstrations. I would like to see some real parts and real world usages.

The friction welding titanium in the first video.....looks like two flat plates. Why not just get a thicker plate?

Same thing for the last video of the two shafts. Why not just get a longer shaft to start with instead of using real expensive machine to make two short pieces into one long one??

 

[GaryM]

I'm not certain, but the second video looked to me like the final product was a wheel. Anyone know for sure?

 

[GLyford]

This is used extensively for aircraft engine parts, like gears and driveshafts. Not all of their customers appreciate videos of their parts being "out in the wild", so a generic demo is used instead for videos. Let us instead say that these processes are being used every day for real parts, and have been at least since the 80's when I saw it.

As far as the two flat plates one, that can actually be a very good finished part, just like that, if the two halves are dissimilar metals. It allows you to weld using regular processes appropriate for each metal onto two structures that are dissimilar, like a steel hull and an aluminum cabin on a boat, at regularly spaced locations. It functions sort of as a mounting bracket without having to somehow get both large parts moving and pressed together.

 

[Gary Fowler]

I can only see it being useful in bonding dissimilar metals together or heavy solid objects where welding is impractical or impossible like in the welding together of solid shafts where electric welding would create warpage and friction welding doesn't plus it is so fast.

Bonding aluminum to steel is a good example of impossible to weld using standard welding techniques. I would think there are lots of uses where you might want one material on one side and a different one on the other side.

 

[woodlandfarms]

So one quick question on this... I assume that these friction welder have some sort of automatic stop? Meaning, I am spinning the object, it is getting melted to the other object, I need to stop the spinning objecti instantly and with no "Bounce" or it might make fracture lines from cooling?

 

[cqaigy2]

I remember trying friction welding while in metal class in high school, back in the mid 70's. We had problems with it stopping quick enough before the "weld" cooled to the point where it would fracture.

 

[Arc weld]

I think the machines that turn the objects have a kind of clutch that releases and both parts will spin after there is enough friction (the parts are welded). I saw a video of Cat rollers being friction welded, not sure if it's the same video.

 

[Creamer]

When i worked at GE Aircraft Engines they used this to attach the disks to the shafts in the engine. It was very controlled in that they had to be at a certain RPM and the force with which they came together was controlled as well as the stopping point and how much relative rotation before they both spun freely together. It didn't look controlled as you see in these videos but it very much was.

 

[GLyford]

In the ones I saw in use, there's a flywheel which is completely decoupled from the drive once the weld starts, and the total energy available is very carefully calculated. The main thing controlling the weld at that point is the compression force and distance. The weld itself is what stops the rotation. When all the flywheel rotational energy is used up, it is done.

I understand that there are also machines which run a drive motor until everything is almost welded, then clutch out just before the end. I imagine trying to duplicate that on a regular lathe would be an exercise in frustration, unless you were willing to make up 100 or so parts to play with to get your parameters right, and take good notes.

I haven't seen any of the linear machines in operation other than in the videos.

 

[dragoneggs]

FSW (Friction Stir Welding) has been blessed by the FAA as an acceptable method of aluminum 'assembly' in aircraft. While not widely used, it is effective using carefully controlled robotic operations. In a home shop... not so much.