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Comment by convolvatron | Hacker News Reader

I tig. wear a helmet and have to buy argon every year. this seems like a huge hassle in comparison. is there that big a difference in quality and or range of processes that make it worth it?

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I know one of the reasons we wanted pico-second and shorter pulsed lasers is that they can cut material with little to no damage of the neighboring material. There was a demo that I read about when this was all brand spanking new research, where they claimed that a laser scalpel causes no heat damage to tissue outside of a cell’s breadth from the contact point.

That's how LASIC and PRK work, after all!

Is it this?

https://en.wikipedia.org/wiki/Coulomb_explosion

It's related, but as i recall the reason that short pulses cut better has to do with heat transfer. Most heat transfer in metal is due to the vibration in the electrons, being much lighter than the atomic lattice they move in. Very short pulses, means that the heating in the beam path happens faster, than the electrons can transfer it out to the rest of the metal. In long pulses once the metal is vaporised, a lot of the surrounding material has melted. This molten metal cools into jagged structures and that leaves the edge weird. All this doesn't happen if the pulse is short enough. It vaporises metal before the surrounding structure has a chance to heat up.

Here's a figure showing the quite stark difference. https://www.researchgate.net/figure/SEM-image-of-the-substra...

Awesome, those photos do illustrate the difference really well.

Thanks heaps. :)

Here's a figure comparing the hole left in a metal surface with normal and femto-second pulses. The difference is quite stark.

https://www.researchgate.net/figure/SEM-image-of-the-substra...

its the operator skill part when dealing with thin sheet metal. It just works better / easier / faster for thin stuff, where in TIG, that's the high-skill work that everyone pays big bucks for.

Agree with the post above, though. The safety setup for lasers is basically full isolation.

seems like its more cost effective to just stay on or above 20ga unless you're really high volume or you really need the weight savings

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