Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Martin Brown <'''newspam'''@nonad.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: MIT 3D printed key components of mass-spectrometer
Date: Tue, 9 Apr 2024 12:47:38 +0100
Organization: A noiseless patient Spider
Lines: 47
Message-ID: <uv39sr$6omr$1@dont-email.me>
References: <uuvss9$986g$1@solani.org> <uv0d2c$3dhmh$1@dont-email.me>
 <hiv71jl2oojqal9kcivl2brh88lron0k4g@4ax.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Tue, 09 Apr 2024 11:47:40 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="1df39aee23763240b51d9a879f9fa1e9";
	logging-data="221915"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX18mC0U1lXeZ0+WKhUrfjdThiJLZWcAf5eXG6B7ar1zF9Q=="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:IchRyqeOkhgDm/7Igog70dM0ZUY=
Content-Language: en-GB
In-Reply-To: <hiv71jl2oojqal9kcivl2brh88lron0k4g@4ax.com>
Bytes: 3307

On 08/04/2024 15:28, 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.

Some of the exotic very crosslinked UV polymers from resin baths might 
not outgas but the sintered stuff would be very problematic. Using 3D 
printing for a variant of lost wax metal casting would be OK though.

Back when I was involved the only polymers allowed in hard vacuum were 
PTFE (which creeps) and PEEK (which is a good engineering plastic). 
Nothing else could stand up to the aggressive baking procedures needed 
to dry them out to hard vacuum.
> 
> 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.

My favourite toy demo on 3D printers is a digital sundial which shows 
the time in a 7 segment style display with 10 minute resolution. 
Adjusting it for summertime is a trivial rotation.

-- 
Martin Brown