Boeing Friction-Stir Welding Machine Investment

$10M investment. Justification: welded joint always lighter than bolted.

There are lots of joining technologies for other things. [Tom holds up a friction stir weld sample.] This is a piece of friction-stir-welded aluminum. A student came to me, wanted to work for NASA. This is how they put together part of the Space Shuttle main tank. Distortion-free, or relatively distortion-free, friction stir weld. Boeing went out and spent ten million dollars building a friction stir welding machine for some of their structures, because a welded joint is always lighter than a bolted joint.

There's mechanical energy. In fact, the only new welding process developed in the last twenty-five years is friction stir welding. If you look at the two hundred welding and cutting processes listed in the back of the welding handbook, you'll find that 150 of them were developed between 1875 and 1925. Another fifty were developed between 1925 and 1975. From 1975 to 2000, there was one new welding process developed. They call it friction stir welding. They take a metal electrode basically like a milling machine, ram it into the surface of the plate between two plates, and forge them together at room temperature. It generates a little friction so it gets warm, but it's a solid-state welding process — there's no melting and almost no distortion. Boeing put in a $10 million facility to weld aluminum plates.

$10M tooling investment that makes one aircraft wing part. Justifiable at $200/lb aircraft economics; not at $2/lb auto economics.

If you can afford the tooling — Boeing built a $10 million tool to do friction welding of parts of aircraft wings, and it just makes one part. That's a lot of investment, but when you're talking $200 a pound saved, and you're making as many aircraft as Boeing is going to make, you can justify it at $200 a pound. But don't expect to see friction welding in automobiles at $2 a pound when you start looking at the capital cost of the equipment.