Reminded me of this great post from a while back, “What if I were 1% charged?”[0] looking at the consequences if you were to remove one out of every 100 electrons in your body.
The answer: a Coulomb explosion powerful enough to rip the vacuum and generate antimatter from the void.
Does anyone know weather this is actually being used in machining now. It seems that while lasers are being widely used in metal fabrication, they are the simpler heat ablation lasers.
If it is being used in practice what are the advantages/disadvantages vis a vis edm?
Yes, although it's a very specialised process. Femtosecond lasers are ubiquitous in semiconductor and thin-film electronics manufacturing, where the dross produced by conventional laser machining is unacceptable. Beyond that, cardiovascular stents are probably the most widespread example - they're made of extremely thin-walled tube that is highly prone to thermal distortion and they require very good edge quality. Femtosecond lasers are increasingly commonly used in the laser texturing of injection mold tools because of the higher surface quality.
You can search for 'femtosecond micromachining' for an idea of the applications where this is being used. Most of the applications are still in high margin markets (aerospace, medical, semiconductor), but there are starting to be consumer applications in particular in the display industry. For example, cutting gorilla glass cleanly is most often done with femtosecond lasers these days.
Popularity is increasing rapidly as the cost for femtosecond lasers has been coming down. Wile you are not going to find a press release from Apple saying that they are installing a particular manufacturing technology on their iphone line, the sales numbers speak for themselves: there is a sizable fraction of 1B/year in sales of femtosecond systems which are being used to build _something_
The working mechanism of femtosecond (and picosecond for that matter) micromachining is the same as the coulomb explosion being discussed here. In the industry it is usually referred to 'athermal' or 'cold' to differentiate from the older system which rely on thermally heating the material to ionize it.
In fact it is mentioned explicitly in the wikipedia article:
>Coulomb explosions for industrial machining are made with ultra-short (picosecond or femtoseconds) laser pulses...Coulomb explosion etching can be used in any material to bore holes, remove surface layers, and texture and microstructure surfaces
It sounds like you're familiar with the field, so I'll accept that you're probably correct here, but the wikipedia article doesn't say what you're claiming.
It says coulom explosions are made with ultra short lasers, not that all ultra short laser pulses result in coulomb explosions, so for someone that doesn't know otherwise, you can't infer that whenever someone says ultra short laser cutting that it happens via coulomb explosions.
Probably not sodium. It's too unreactive for that.
You've no doubt seen the sodium explosions, but what actually explodes is hydrogen, not sodium itself. If you run water+sodium reaction in an inert atmosphere, or simply weigh down a chunk of sodium so it quickly sinks to the bottom of the vessel, the result is much more tame.
On the other hand, starting with potassium, you probable start to get enough charge separation to tear apart solid chunks of metal.
Would be nice to see some more concrete data/references. This is a big claim. I mean, if it is "basically the same" but "faster and requires fewer examples" you can just say that it's "strictly better" than K-means, and stop using K-means ever. However, everybody is aware of K-means and personally it's the first time I hear about "Columb exemplar algorithm".
The answer: a Coulomb explosion powerful enough to rip the vacuum and generate antimatter from the void.
[0]: https://gravityandlevity.wordpress.com/2013/05/22/what-if-i-...