<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>
<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>

CC BY-SA 4.0
2021-06-17T14:54:24.117Z
The need for higher extrusion temperature is what I would expect.  However, that's assuming the same function between the brittle cold temperature and the almost liquid phase.
Perry Webb
CC BY-SA 4.0
2021-06-17T14:42:03.947Z
2021-06-17T14:42:03.947Z
Zeiss Ikon
<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.
But for whichever material is used, thermal cycling may be a problem.</p>

CC BY-SA 4.0
2021-06-18T01:46:42.637Z
Welcome to 3D Printing SE and thank you for your contribution. When you get a chance, please take the [tour] to understand how the site works and how it is different than others.
agarza
CC BY-SA 4.0
2021-06-18T21:39:19.343Z
Thank you for the suggestion--I will try it. Unfortunately for my purposes, -70C compliance is essentially meaningless to me (of course assuming you did not mean 70K). The temperatures I am referring to are an order of magnitude lower ~ -459.67C.  I am sure thermal cycling is a potential issue that could induce material fatigue characteristics.
John Marangola
CC BY-SA 4.0
2021-06-17T22:12:38.623Z
2021-06-17T22:12:38.623Z
user3324888
<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>

CC BY-SA 4.0
2021-06-17T13:57:27.690Z
What plastics do you already know can take the cold soaks you describe?  Perhaps thermosets rather than thermoplastics (which would suggest an SLA rather than FDM print)?
Zeiss Ikon
CC BY-SA 4.0
2021-06-17T14:05:10.747Z
Do you know a thermoset that would be good to experiment with for testing out these low temperature constraints?
John Marangola
CC BY-SA 4.0
2021-06-17T14:07:16.203Z
Not offhand, just exploring options.  I don't work in cryogenics, I repair power tools.  I thought it might be possible to just look up the properties of various plastics, like we used to do with the "Rubber Bible" -- CRC manual -- when I was in college ~40 years ago.
Zeiss Ikon
CC BY-SA 4.0
2021-06-17T16:43:59.547Z
Of course, steel works better than plastics when very cold.
Perry Webb
CC BY-SA 4.0
2021-06-18T13:51:53.110Z
@PerryWebb Actually, most steels become very brittle when chilled, even well above liquid nitrogen temperature.  There are recorded cases of cold-induced brittleness causing failures in building structures (under construction) at fairly ordinary outdoor winter temperatures.
Zeiss Ikon
CC BY-SA 4.0
2021-06-18T13:59:41.313Z
True, but even brittle steal is much stronger than plastic, as long as you aren't hammering on it or bending it.  If both the steel and plastic become brittle, the plastic will break first.  Put a steel ball from a bearing and a rubber or plastic ball in liquid N2, then throw them on the floor to see which will break first.
Perry Webb
CC BY-SA 4.0
2021-06-18T14:08:48.610Z
Another example: a steel trashcan will usually hold LN2 OK, but a plastic trashcan will usually crack if filled with LN2.  Teflon tends to hold up well at LN2 temperature.  It would make good bearings but too slick for pulleys  and a difficult melting point for printing.
Perry Webb
CC BY-SA 4.0
2021-06-19T17:33:00.580Z
Yes, it would be ideal to machine the part of steel, however it is much easier to print it for the purposes of prototyping.
John Marangola
<filament><filament-choice><temperature>
Lowest temperature PLA pulley print will withstand
John Marangola
# Lowest temperature PLA pulley print will withstand

(Asked by: username_0 on 2021-06-17)

I am looking to print an HTD Timing Belt pulley to be used in a laboratory setting that can get *very* cold for extended periods of time. By "very cold" 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.

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.

**Tags:** filament, filament-choice, temperature
> **Comments:**
> **username_1**: What plastics do you already know can take the cold soaks you describe?  Perhaps thermosets rather than thermoplastics (which would suggest an SLA rather than FDM print)?  
> **username_0**: Do you know a thermoset that would be good to experiment with for testing out these low temperature constraints?  
> **username_1**: Not offhand, just exploring options.  I don't work in cryogenics, I repair power tools.  I thought it might be possible to just look up the properties of various plastics, like we used to do with the "Rubber Bible" -- CRC manual -- when I was in college ~40 years ago.  
> **username_2**: Of course, steel works better than plastics when very cold.  
> **username_1**: @PerryWebb Actually, most steels become very brittle when chilled, even well above liquid nitrogen temperature.  There are recorded cases of cold-induced brittleness causing failures in building structures (under construction) at fairly ordinary outdoor winter temperatures.  
> **username_2**: True, but even brittle steal is much stronger than plastic, as long as you aren't hammering on it or bending it.  If both the steel and plastic become brittle, the plastic will break first.  Put a steel ball from a bearing and a rubber or plastic ball in liquid N2, then throw them on the floor to see which will break first.  
> **username_2**: Another example: a steel trashcan will usually hold LN2 OK, but a plastic trashcan will usually crack if filled with LN2.  Teflon tends to hold up well at LN2 temperature.  It would make good bearings but too slick for pulleys  and a difficult melting point for printing.  
> **username_0**: Yes, it would be ideal to machine the part of steel, however it is much easier to print it for the purposes of prototyping.  

---

## 2 answers

### Answer by username_1 on 2021-06-17. Score: 1 | Accepted answer

I found [this article](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.) 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.

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.

> **Comments:**
> **username_2**: The need for higher extrusion temperature is what I would expect.  However, that's assuming the same function between the brittle cold temperature and the almost liquid phase.  

---

### Answer by username_3 on 2021-06-17. Score: 0

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.
But for whichever material is used, thermal cycling may be a problem.

> **Comments:**
> **username_4**: Welcome to 3D Printing SE and thank you for your contribution. When you get a chance, please take the [tour] to understand how the site works and how it is different than others.  
> **username_0**: Thank you for the suggestion--I will try it. Unfortunately for my purposes, -70C compliance is essentially meaningless to me (of course assuming you did not mean 70K). The temperatures I am referring to are an order of magnitude lower ~ -459.67C.  I am sure thermal cycling is a potential issue that could induce material fatigue characteristics.  

---

