The Race to Seal Helium HDDs (2021) • Hacker News Board

Re: The Race to Seal Helium HDDs (2021)

#51

Post by adrian_b » Tue, Jul 09, 2024, 1:24 PM UTC

alright2565 wrote: post #48

cainxinth wrote: post #47

The solution: - They moved all the casing openings to the top of the drive and used a thin metal foil as a second cover. - They adapted laser welding techniques from the satellite industry to seal the foil to the casing without damaging components with excess heat. - They found an aluminum alloy used in aerospace that could withstand the laser welding without cracking. - To get electricity and data in and out without…

> used glass-metal feedthroughs I wonder if this is still the case. I took a WD helium hard drive apart recently and I think I saw just a PCB glued in place for the electrical signals. Probably made from very special materials, but it looked just like usual.

Glass-metal feedthroughs have been the standard means of connecting semiconductor devices during the first decade of their existence, when they were packaged in hermetic cases made of either metal or glass. Their main problem is to use pairs of special kinds of glasses and of metal alloys that are matched in their thermal expansion coefficients.

After 1960, better passivating methods for the semiconductor chips have been developed, so the hermetic packages have been slowly replaced with plastic packages for most applications.

It is likely that the PCB glued in place covers the glass-metal feedthroughs, which have metal pins that are inserted in connectors soldered on the PCB. It is impossible for any case that contains helium to have any part made of plastic in any of its walls. Plastic parts like a PCB can only be attached externally.

Re: The Race to Seal Helium HDDs (2021)

#52

Post by adrian_b » Tue, Jul 09, 2024, 1:38 PM UTC

bjoli wrote: post #50

vertnerd wrote: post #19

"Helium is notoriously difficult to contain. Its atoms are some of the tiniest in the universe." It's a good article, and I learned a lot, but every so often it reads like something an 8th grader would write the night before their paper is due.

And here I was, thinking helium was the tiniest atom unless you start counting cations which has it beaten by Li+ and He+

Yes, at the same number of electrons, the heavier atoms have a smaller volume, i.e. they are tinier, because their greater nuclear charge attracts the electrons closer to the nucleus.

Li+, Be++, B+++ are tinier than He, but they are ions, not neutral atoms. Neutral Li, Be, B are bigger than He, because they have an additional electron layer. Both neutral H and H- are bigger than He, because their one or two electrons are attracted less by a proton than by a He nucleus with double charge. H+ is just a bare proton, so it is orders of magnitude smaller than any other ion, but it is not a neutral atom.

So He is indeed the smallest neutral atom.

Re: The Race to Seal Helium HDDs (2021)

#53

Post by ejdhshsuwisjsh » Tue, Jul 09, 2024, 1:39 PM UTC

ahartmetz wrote: post #33

ejdhshsuwisjsh wrote: post #31

Earlier quoted context omitted.

The article talks about how hard it is to contain helium. Why would you assume that a basic metal foil would keep helium indefinitely?

It's right there in the article: it mentions welding of aluminum foil seals - for helium. I have also worked with high vacuum in lab exercises. There's a leak finder apparatus using helium because helium creeps through the smallest leaks - but they have to be leaks! Hydrogen just diffuses through anyway, though not quickly through thick metal (I have that from Wikipedia).

I have to read up on this.

I have seen a YT on someone doing this in a lab env but I always assumed that you can't contain it indefinitely

Re: The Race to Seal Helium HDDs (2021)

#54

Post by hughesjj » Tue, Jul 09, 2024, 1:47 PM UTC

rasz wrote: post #13

wigster wrote: post #3

if helium is better, why not use a vacuum?

Heads ride on cushion of gas, would instantly friction weld into platters in vacuum.

Friction or cold/vacuum welding at that point?

Re: The Race to Seal Helium HDDs (2021)

#55

Post by adrian_b » Tue, Jul 09, 2024, 1:51 PM UTC

credit_guy wrote: post #49

ahartmetz wrote: post #29

Earlier quoted context omitted.

Hydrogen even diffuses through (and into) metal - seems not doable, not cheaply and without maintenance at least.

Helium atoms are actually smaller than hydrogen atoms, and much smaller than hydrogen mollecules.

While that is true, there are metals through which hydrogen can diffuse faster than helium, because the hydrogen molecules dissociate and ionize when entering the metal and the hydrogen ions diffuse through the metal individually.

Re: The Race to Seal Helium HDDs (2021)

#56

Post by Towaway69 » Tue, Jul 09, 2024, 3:09 PM UTC

ricardobeat wrote: post #36

Towaway69 wrote: post #35

> Western Digital ships about a million helium-sealed drives every month. I'm surprised that there was such demand for spinning disks, I would have thought SDDs would have replaced them all. I say ‚was‘ as the article is from 2021.

SSDs are still too expensive for high volume storage. Enterprise purchases will be much lower, but as a consumer you can buy a 12TB helium-sealed HDD for $100-$200, while solid state alternatives don’t even reach that capacity in a single unit and cost 5-10x more.

Thanks for the explanation, I didn’t realise that was the case.

Re: The Race to Seal Helium HDDs (2021)

#57

Post by chasil » Tue, Jul 09, 2024, 4:13 PM UTC

vertnerd wrote: post #19

"Helium is notoriously difficult to contain. Its atoms are some of the tiniest in the universe." It's a good article, and I learned a lot, but every so often it reads like something an 8th grader would write the night before their paper is due.

Would neon offer some degree of these benefits?

Is neon more plentiful than helium?

Edit: No.

"...neon is comparatively scarce on Earth... It is primarily obtained through the fractional distillation of liquid air, making it significantly more expensive than helium due to air being its sole source."

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

Re: The Race to Seal Helium HDDs (2021)

#58

Post by kbelder » Tue, Jul 09, 2024, 4:17 PM UTC

What would happen if you had a rigid structure that helium could permeate, but nothing larger could, and then filled it up with helium and waited?

Would most of the helium exit, until it was balanced with just the partial pressure of helium in the atmosphere? That would be nearly a vacuum, wouldn't it?

Re: The Race to Seal Helium HDDs (2021)

#59

Post by mitthrowaway2 » Tue, Jul 09, 2024, 4:34 PM UTC

dtx1 wrote: post #40

aaron695 wrote: post #34

Earlier quoted context omitted.

> Hydrogen would also be .. interesting ... Why? It's used in power station generators. Why would a hard disk be interesting? https://en.wikipedia.org/wiki/Hydrogen-cooled_turbo_generato...

Cause exploding hard drives are metal AF

It won't explode until it's mixed with oxygen.

Re: The Race to Seal Helium HDDs (2021)

#60

Post by writeslowly » Tue, Jul 09, 2024, 4:59 PM UTC

cainxinth wrote: post #47

The solution: - They moved all the casing openings to the top of the drive and used a thin metal foil as a second cover. - They adapted laser welding techniques from the satellite industry to seal the foil to the casing without damaging components with excess heat. - They found an aluminum alloy used in aerospace that could withstand the laser welding without cracking. - To get electricity and data in and out without…

They also invented a new welding technique to control some sort of aluminum micro-explosions