Welding breakthrough could transform manufacturing

https://phys.org/news/2019-03-welding-breakthrough.html

by gooseus • 7 years ago

105 29 7 years ago

Tor3• 7 years ago

Very interesting. Welding glass and metal together instead of using an adhesive. This could be big, depending on how long-term testing comes out. The trick seems to be to use picosecond laser pulses to avoid running into thermal issues with the very different materials.

benj1113• 7 years ago

So could we see the return of square windows to aircraft? This would allow that right?

https://en.m.wikipedia.org/wiki/De_Havilland_Comet

serf• 7 years ago

The square windows didn't do the Comet in, it was poor engineering and testing, leading to improper fuselage reinforcement.

It's covered in that wikipedia article that you linked under 'Window shape misconception'.

benj1113• 7 years ago

Ok I'm trying to parse that, and marry that with my own understanding.

The linked article seems to suggest that window corners weren't the cause of the crashes. My understanding is that corners can lead to propagation of cracks etc, thus why modern aircraft window have a large window radius. And large radius windows require less reinforcement, and thus weight.

They aren't contradictory are they?

Edit: Missing word.

Cthulhu_• 7 years ago

Probably not, using square windows will still have stress points on the corners regardless of the manifacturing process used.

sjcsjc• 7 years ago

"The process relies on the incredibly short pulses from the laser. These pulses last only a few picoseconds — a picosecond to a second is like a second compared to 30,000 years."

Nice bit of exposition.

lozaning• 7 years ago

You might enjoy this video of Grace Hopper explaining how to visualize a nanosecond http://www.youtube.com/watch?v=JEpsKnWZrJ8

cmroanirgo• 7 years ago

Wonderful. For the time it takes an electron to travel in 1 microsec (in vacuum, yada, yada):

984 feet ... We oughta hang one over every programmers desk, or over their neck (:audience chuckles:), so they know what they're throwing away when they're throwing away microseconds.

panic• 7 years ago

This seems to be the original press release from the university website: https://www.hw.ac.uk/about/news/2019/welding-breakthrough-co...

ganzuul• 7 years ago

Have we forgotten lightbulbs, CRTs, and a myriad of other vacuum tubes used to be a thing? They used the alloy 'kovar' for much greater temperature variation tolerance than this new tech was tested for.

syntaxing2• 7 years ago

Kovar is still widely used. Besides the low thermal expansion coefficient, the thermal expansion is extremely close to quartz which makes it ideal for optic purposes.

cimmanom• 7 years ago

This won’t eventually lead to the glass cracking as temperature changes cause the metal to expand and contract?

senorprogrammer• 7 years ago

No, the terms picosecond and micron are pretty integral to the process. Imagine using a propane torch to heat up the side of a single brick in an apartment building wall for a few seconds. The temperature change in that brick, considerable compared to all the others, will have effectively no impact on the building itself.

yetihehe• 7 years ago

Yeah, but it's about long term stresses leading to cracking. I wonder how big elements you can weld with this. Centimeter scale windows for chips will probably have no problems. While screens in mobile phones - I suppose they will crack within weeks/months.

jcims2• 7 years ago

Definitely possible, but I think that's something you could engineer your way out of by being very selective with materials, building in strain relief. Then of course test test test.

a3n• 7 years ago

Then of course test test test.

That's what customers are for.

d-sc2• 7 years ago

As long as the thermal strain(deformation) and therefore stress is managed, it would be fine. There are design tables and values that one can refer to that limit maximum cyclic stress which might be particularly applicable here.

aristophenes• 7 years ago

I wonder how long until no one can repair phones anymore, because they are welded shut.

ddebernardy• 7 years ago

Seems unlikely IMHO. Devices need or will need to be serviceable or recyclable in some places.

taneq• 7 years ago

It's kind of dubious whether phones can really be repaired now. It's often possible to get a phone running again but it's never going to be quite the same after it's been pulled apart. I'd draw the line at the point where they started gluing them shut instead of using screws and (reusable) clips.

d-sc2• 7 years ago

We have glues that for practical purposes would be just as hard to repair.

Repairability is generally a choice of the designer/manufacturer.

Cars have lots of welding on them and are still plenty repairable.

tromp• 7 years ago

This could make titanium rimless glasses even more minimal, no longer needing to drill through the glass.

syntaxing2• 7 years ago

I'm kind of confused...Isn't laser welding a pretty well studied technique? Laser welding is pretty common for high tech industrial products. Is the breakthrough the mix of materials? Even then I've seen different plastics laser welded together. Also, pico laser has been the industry standard for lasers for a while now. The main race is getting a robust fempto laser.

Welding breakthrough could transform manufacturing

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