On Sat, 6 Jan 2024 10:31:52 +0000, Martin Brown wrote:
On 05/01/2024 12:29, Jeroen Belleman wrote:
On 1/5/24 05:30, Jan Panteltje wrote:
Researchers 3D print components for a portable mass spectrometer MIT
news:
https://news.mit.edu/2024/researchers-3d-print-components-portable- mass-spectrometer-0104
So they 3D-print the electrodes and their supports from some
glass-ceramic-resin composite and then use electroless metal deposition
on the surfaces that are to become the electrodes. Metallizing just the
electrodes while avoiding the support structure might be fiddly.
I'd be surprised if it didn't outgas essentially forever using that manufacturing technique. Lost wax casting might stand more chance...
I think that the 800C rating of the glass-ceramic material should be
adequate for bake-out, and as you point out below ultra-high vacuum is not required for quadrapole MS. The study was funded by a company in the
medical MS business, probably not out of kindness.
Likely suspect for the 3D printing system:
<
https://3dprintingindustry.com/news/breakthrough-ceramic-glass-material- for-3d-printing-launched-by-lithoz-and-glassomer-221583/>
<
https://lithoz.com/en/lithoz-and-glassomer-launch-innovation-partnership- presenting-lithaglass-powered-by-glassomer-a-3d-printable-quartz-glass- for-high-performance-applications/>
"LithaGlass ... a composite slurry with a base of quartz glass ...
The design freedom of 3D printing combines with the desirable properties
of high-performance fused silica glass – such as mechanical stability and high thermal and chemical resistance, as well as low thermal expansion and
a resulting high thermal shock resistance. With LithaGlass being closer to
a ceramic than standard glasses like soda lime glass, it also has the
desirable material properties of fused silica glass including a low
thermal expansion and high thermal shock resistance."
Sparse on details, but likely any resin used as binder is baked out in the process of heating to particle fusing temperature, although post-printing processing is not discussed. If they have a resin that can withstand the
800C working temp of the finished product that would be rather
impressive. Perhaps they are using some non-polymer binder with no post processing required, they have not identified any component of the slurry except for silica.
I think the traditional rod electrodes weren't the hardest part in a
mass spectrometer anyway. The vacuum system and a reliable sample input
port are what makes it expensive.
Particularly for the precision hard vacuum of magnetic sector mass specs which are typically baked to 150C to get the last traces of water off
the internal surfaces as a part of commissioning. It was bad news if
someone left a screwdriver inside at that stage (and it did happen).
When I was involved in that game only a handful of plastics could handle
that sort of abuse PTFE and the engineering plastic PEEK.
Quadrupoles will tolerate a much worse vacuum - I can't recall by how
much but ICPMS effectively works with a pinhole facing a 8000K plasma at
1ATM and some Faraday cup and turbo pump based ones could survive
without interlocks. The main difficulty was keeping the sampling orifice
from melting! Classic ones with oil diffusion pumps you had a very big cleaning job to do if the vacuum protection system interlocks failed.
The high end ones with ion counting sensors in needed a decent vacuum
all the time and a photon stop to avoid the sensor seeing the plasma
flame. They had sophisticated interlocks to prevent various forms of catastrophic failures like meltdown, fire, flood and other mayhem.
--- SoupGate-Win32 v1.05
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