<p>I am looking to print an HTD Timing Belt pulley to be used in a laboratory setting that can get <em>very</em> cold for extended periods of time. By &quot;very cold&quot; I mean adjacent metal chambers get cooled with liquid nitrogen to lower than -200 °C. For the purposes of having a threshold temperature tolerance, assume that the metal chambers coming directly in contact with the pulley may get as cold as mK close to absolute zero.</p>
<p>While it was my intention to print this pulley out of PLA, I am unsure whether or not it will be able to withstand negative temperatures of this magnitude or if it will become brittle--or something else will happen to the structure of the print when it experiences these temperatures. I am open to printing any other material if there are some materials that will hold up better than PLA for low temperatures. It is preferable for me to print this part instead of machine it for the sake of a deadline. I was also wondering if there is some infill pattern, infill density, or other structural print parameters that would help reinforce a printed part against becoming brittle when imposed to such low temperatures.</p>

[{'answer_id': 16554, 'author': 'Zeiss Ikon', 'author_id': 28508, 'author_profile': 'https://3dprinting.stackexchange.com/users/28508', 'pm_score': 2, 'selected': True, 'text': '<p>I found <a href="https://www.curbellplastics.com/Research-Solutions/Technical-Resources/Technical-Resources/Plastic-Materials-in-Cryogenic-Environments#:%7E:text=Plastics%20offer%20a%20number%20of,wear%20surfaces%20without%20external%20lubrication." rel="nofollow noreferrer">this article</a> which seems to suggest PTFE is a good choice of plastic for a cryogenic environment.  I\'ve read that there are PTFE filaments available for FDM printers, though there are some caveats.  First, you will need an all-metal hot end; enough heat to melt a PTFE filament will melt the PTFE filament guide if it is in contact with the nozzle.  Second, you will likely need to edit your printer\'s firmware to permit printing at the high temperatures required.  Third, it may require some testing to determine whether FDM printed PTFE will meet your mechanical needs (shear strength, layer adhesion, etc.) and fourth, you might need an unusual build surface, since the polymers used for many existing surfaces can\'t take the temperatures needed for bed adhesion.</p>\n<p>Finally, as with a PTFE guide tube in contact with the nozzle, at the temperatures required you need to be aware of and take precautions against outgassing by the melting PTFE.</p>\n'}, {'answer_id': 16557, 'author': 'user3324888', 'author_id': 28554, 'author_profile': 'https://3dprinting.stackexchange.com/users/28554', 'pm_score': 0, 'selected': False, 'text': '<p>You could try PETG. PETG labware works down to -70, and there is a video clip where a PET bottle filled with liquid nitrogen that withstands appreciable pressure.\nBut for whichever material is used, thermal cycling may be a problem.</p>\n'}]
['https://3dprinting.stackexchange.com/questions/16552', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/28970/']