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From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: MIT 3D printed key components of mass-spectrometer
Date: Tue, 9 Apr 2024 01:17:21 +1000
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On 9/04/2024 12:28 am, 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.

It wouldn't be much use in a mass spectrometer if it did.
Out-gassing vaccuum systems always involves getting them hot for quite a 
while and pumping them hard. Maybe you have to laser fuse a thin layer 
over the entire surface while maintaining a high vaccuum.

> 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.

As Phil Hobbs says, the printers are cheap so you can put a lot in 
parallel. The post-processing to get the outgassing down might not be so 
easily paralleled.

-- 
Bill Sloman, Sydney