4 ms·

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 techniqu

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 breaking the seal, they used glass-metal feedthroughs similar to those used to seal Freon in refrigerators. - To get the solder to adhere when attaching the feedthroughs, they used a nickel plating mask.

alright2565 2y ago
> 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.
- adrian_b 2y ago
  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.
writeslowly 2y ago
They also invented a new welding technique to control some sort of aluminum micro-explosions
deleted 2y ago
[deleted]
kragen 2y ago
thanks, this is great! to add a bit more context: - laser welding has been in use since 01967 and is used not only for satellites but also for auto body panels, pacemakers, 3-d printing (sls/slm), batteries, etc. - glass-metal feedthroughs are used in incandescent lightbulbs, fluorescent tubes, neon tubes, and vacuum tubes (including crts and electron microscopes), because in all cases you need a vacuum-tight seal around the wires that lead into the tube. special glass formulations with custom thermal expansion coefficients have been available for this purpose since at least the 01950s. the refrigerator guys may have the cheapest ones but they didn't invent them - nickel plating is the conventional way to make steel solderable with electronic solders since forever. it's also used, for example, to make battery tabs solderable. i think this goes back to the 19th century that is, the design process the article depicts is considerably less daringly original than the author makes it sound. the people who made it work deserve a lot of praise, but because manufacturing is hard and they had to solve a lot of hard problems, not because they're geniuses doing totally unprecedented things with brilliant strokes of insight. the author makes it sound like that presumably because she doesn't know anything about the problem space if you like that kind of thing, you'll probably enjoy dalibor farný's youtube channel where he documents his process of solving the problems of his nixie tube factory (including vacuum-tight glass-metal seals) in a czech castle https://www.youtube.com/@daliborfarny/videos https://www.youtube.com/@daliborfarny/videos

alright2565 2y ago

> 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.

adrian_b 2y ago
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.

writeslowly 2y ago

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

deleted 2y ago

[deleted]

kragen 2y ago

thanks, this is great! to add a bit more context: - laser welding has been in use since 01967 and is used not only for satellites but also for auto body panels, pacemakers, 3-d printing (sls/slm), batteries, etc. - glass-metal feedthroughs are used in incandescent lightbulbs, fluorescent tubes, neon tubes, and vacuum tubes (including crts and electron microscopes), because in all cases you need a vacuum-tight seal around the wires that lead into the tube. special glass formulations with custom thermal expansion coefficients have been available for this purpose since at least the 01950s. the refrigerator guys may have the cheapest ones but they didn't invent them - nickel plating is the conventional way to make steel solderable with electronic solders since forever. it's also used, for example, to make battery tabs solderable. i think this goes back to the 19th century that is, the design process the article depicts is considerably less daringly original than the author makes it sound. the people who made it work deserve a lot of praise, but because manufacturing is hard and they had to solve a lot of hard problems, not because they're geniuses doing totally unprecedented things with brilliant strokes of insight. the author makes it sound like that presumably because she doesn't know anything about the problem space if you like that kind of thing, you'll probably enjoy dalibor farný's youtube channel where he documents his process of solving the problems of his nixie tube factory (including vacuum-tight glass-metal seals) in a czech castle https://www.youtube.com/@daliborfarny/videos https://www.youtube.com/@daliborfarny/videos