The smallest weld you'll ever see!

[Maker]

Okay, that was a bit clickbaity, but I'm truly astonished:


That's my phone zoomed in x8, looking through a microscope at x25, so 200 times bigger than it really is.


That's x25, the small lines on the rule are a hundredth of an inch apart.


No magnification, and a slightly grubby finger.


I'm amazed, how on earth is such a tiny weld welded?

 

[matt1978]

Probably some sort of laser welding

 

[WorkshopChris]

It that formed from a collar that both threaded parts push into then the weld penetrates through the collar into the parts inside to fuse the lot together?

 

[Justme]

Why?

Looks like a crimp would work just as well.

 

[Richard.]

I would certainly say automated maker. Looks possibly like orbital tig.
With a tiny electrode and enough pace on the part orientation you'd be surprised at just how tiny and pin point accurate an orbital tig set up can be.

 

[voipio]

Thermocouple welds can be quite a bit smaller, and are normally done using a specialised TIG welder.

 

[Maker]

They're not threads, it's a tight coil of stainless wire forming a tube with another wire free to move down the middle, I can only imaging crimping it would collapse the tube part and prevent the inner bit from sliding. It's like a tiny bowden cable, the join is between a slightly more rigid bit and a slightly more flexible bit.

 

[slim_boy_fat]

Maybe it was done by this fella

 

[andymfell]

I've seen smaller

the ends of a coil spring made from 316 to create a garter spring wire diameter of down to 20 thou welded together

like the springs used in rotary oil seals

presumably made using some automated method or just resistance welded

 

[KMP]

Interesting and impressive but in reality a production technique designed to complete the task with cheaper automation. There are several types of welding process that could weld the ends of the coil spring together without the use of the collar. That looks as if it is either a rotary (orbital) TIG process or more likely looking at it a seam or sequential spot weld technique. Even a resistance welder might be able to do that if the coiled spring is resilient enough to allow for reasonable penetration without distortion. The collar would also aid that.

To get to much smaller welds then you would need to look at Electron Beam Welding, Laser Welding or even Resistance Welding in it's miniature guise. Unfortunately, these systems are unlikely to ever make it into the hobby welder field, we ran a Electron Beam welder over 30 years ago welding Gas Turbine Blades but the basic machines started at £1,000,000 and the running costs were very, very high. Controlling penetration of several inches to a tolerance of +/- 0.001" was the norm even that long ago. Laser welding is cheaper and challenges EBW in many aspects but cannot match the penetration available with the older technology. Machines in the cost bracket I indicated would do maybe 2" but the technique could achieve 8" penetration if you could afford it.

Very interesting thread thank you, I enjoyed remembering "those halcyon" days of my job.

Keith

 

[Brad93]

That's probably laser welded or done with a Plasma Arc Welder. Orbital TIG I would imagine the ripples to be tighter together.

 

[Rocketman]

It actually amazes how much laser welding is done these days. 15 years ago it was just coming in for tool repairs but now it is pretty mush all tool repair welds.

 

[daedalusminos]

Pulse shaped laser welding I'd say...