Friction Welding

[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.