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From: Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>
Newsgroups: sci.electronics.design
Subject: Re: MIT 3D printed key components of mass-spectrometer
Date: Tue, 9 Apr 2024 00:38:59 -0000 (UTC)
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Glen Walpert <nospam@null.void> wrote:
> On Mon, 8 Apr 2024 10:49:34 -0400, Phil Hobbs wrote:
> 
>> On 2024-04-08 10:28, John Larkin wrote:
>>> On Mon, 8 Apr 2024 10:23:24 +0100, Martin Brown
>>> <'''newspam'''@nonad.co.uk> wrote:
>>> 
>>>> On 08/04/2024 05:47, Jan Panteltje wrote:
>>>>> Researchers 3D print key components for a point-of-care mass
>>>>> spectrometer
>>>>> https://www.sciencedaily.com/releases/2024/04/240404113429.htm
>>>>> pdf:
>>>>> https://pubs.acs.org/doi/10.1021/jasms.3c00409
>>>>> 
>>>>> Massachusetts Institute of Technology Summary:
>>>>> Researchers 3D printed a miniature ionizer, a key component of a mass
>>>>> spectrometer. Their device could someday enable an affordable,
>>>>> in-home mass spectrometer for health monitoring.
>>>> 
>>>> It is complete nonsense. Making the hard vacuum needed for ions to
>>>> move freely in mass spectrometry and sample handling to introduce the
>>>> sample into the unit without losing vacuum are fundamentals that won't
>>>> go away.
>>>> 
>>>> The closest to a quick dirt cheap MS is time of flight laser ablation
>>>> if your sample is a solid or can be put on one. Liquid samples are
>>>> really messy and water vapour is the bane of vacuum systems.
>>>> 
>>>> Selective ion probes offer a much better alternative for bio samples
>>>> (I suppose the MIT PR department has to justify its existence
>>>> somehow).
>>> 
>>> I'd expect 3D printed stuff to outgas forever.
>>> 
>>> 3D is super slow, too. I've heard of modestly complex parts taking days
>>> to fab. The upside is that it can make things that are impossible to
>>> machine or mold.
>>> 
>> 3D resin printers are super cheap nowadays, and can do beautiful things.
>> They're basically contact printers made with 8k display LCDs and UV
>> LEDs, and give you nice repeatable 17-micron voxels.
>> 
>> It doesn't matter so much that something takes a day to print, if you
>> can have a shelf full of printers for $2k.
>> 
>> Cheers
>> 
>> Phil Hobbs
> 
> Not all 3D printers use resin, for instance:
> 
> <https://www.nasa.gov/humans-in-space/nasa-tests-3-d-printed-rocket-part-
> to-reduce-future-sls-engine-costs/>
> 
> This isn't the first 3D printed part in the RS-25 engine (evolved from the 
> SSME), just the largest so far.  The printer for beach-ball size titanium 
> parts might cost a bit more than $2k and probably won't fit on a shelf, 
> but I bet those helium-tight components don't outgas much :-).
> 

Fun. The resin printers start at around $100, though.  I’m very willing to
trade off the ability to print titanium for that. ;)

> (I did the detail, process and tooling designs for the HP oxidizer 
> turbopump shaft seals for the original SSME ~1980, per proposal design and 
> design rules by the late Dr. Philip Stein, PhD in metallurgy from MIT 1927 
> IIRC.  LOX on one side, hot H2 and steam on the other, lube oil mist and 
> bearings in between, ~28k RPM shaft with play and significant thermal 
> movement, engines shut down automatically if either seal fails.  So I 
> check now and then to make sure none of my parts have failed :-).

An excellent idea. 
I do the same with my body parts. ;)
> 
> Glen
> 


Cheers 

Phil Hobbs 
-- 
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics