I’m designing a part that will need to be autoclaved—it will be under steam at 121°C for about 15 min per job and I will want it to be able to go through the autoclave repeatedly. I ran a test PLA part through the autoclave and it warped noticeably; based on their glass transition temperatures, ABS (105ºC) and PETG (80ºC) would probably also not hold up. For a consumer-grade FDM printer, what filament materials that could be used for parts that could be autoclaved?
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asked May 20, 2019 at 22:21
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2$\begingroup$ What do you consider common filaments? This PEEK filament specifically lists its resistance to autoclaving up to 250C. 3dxtech.com/carbonx-carbon-fiber-peek-3d-printing-filament The other PEEK and PEKK filaments there also list high continuous use temperatures and glass transition temps. It takes nozzle temperatures in the 400C range and bed temp above 130C, but it you want high temperature resistance you're going to need to be able to print at fairly high temperatures. $\endgroup$– T. M.Commented May 20, 2019 at 23:49
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$\begingroup$ Doesn't PLA need >180C to melt? My spool from MG Chemical is labelled 200-210C. 121C is way below that. digikey.com/products/en/maker-diy-educational/… I don't see any under 185C as the lowest temp. I've only been 3D printing about a week (after solving several assembly issues), but I would think 60C below the lowest material extruding temperature would be okay. ABS is even higher, I recall 230 being the lowest extrudable temp. $\endgroup$– CrossRoadsCommented May 21, 2019 at 16:17
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2$\begingroup$ @CrossRoads: I had PLA wine charms that "melted" in the dishwasher, which doesn't even get to boiling... $\endgroup$– dandavisCommented May 21, 2019 at 18:51
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1$\begingroup$ I don’t have the expertise others here do but the e3d v6 can reach high temps especially if it has a higher temp pt100 thermocouple and compatible heater block. The bigger problem would be the heated bed that might not be hot enough. Also if you autoclave at 121C, there must be some filament in the middle between that and peek that can handle that temperature. $\endgroup$– T. M.Commented May 21, 2019 at 23:08
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1$\begingroup$ Anything that prints that hot also needs an enclosure. $\endgroup$– TrishCommented May 22, 2019 at 2:40
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2 Answers
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It might seem that common 3D printer materials such as PLA and ABS should be capable of being autoclaved—unfortunately. However, although their melting temperatures are higher than autoclave temperature (typically 121ºC), their glass transition temperatures are below that limit so they can warp or undergo creep deformation.
Sterilization of numerous plastics is described here, with PLA, ABS, and PET all being described as "poor" for autoclaving. For each "good" material on that list, I looked for filament by Googling and consulting material guides from Prusa and Matter Hackers.
Polypropylene (PP) or acetal (POM, also known as Delrin) are the best choices. Filament is available for PEEK, PEI (ULTEM), FEP, PPSU, and PPS but these filaments are expensive (>$100/kg) and require high extruder temperatures (>300ºC).
In contrast, PP is about $50/kg and uses an extruder temperature of 254ºC; POM is similarly priced and uses an extruder temperature of 210ºC. Nylon (depending on the exact type) and HT-PLA may also be worth considering.
"High temperature" filaments are not worthwhile for this application. Again, they're expensive and, more significantly, do not work well with consumer-grade 3D printers. For example, the upper limit for a Prusa i3 MK3s is about 280ºC—the thermistor only is good up to that temperature. Higher temperatures would require swapping out sensors and modifying firmware and building an enclosure. It's been done. Printers designed for high-temperature filaments easily cost thousands of dollars.
This question was previously asked on Reddit a few times but this analysis is more comprehensive.
answered May 22, 2019 at 4:03
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$\begingroup$ At work, colleagues print PLA parts and cycle them in an autoclave session. But for high temperatures and long exposure and frequently reuse, they print them in aluminium. $\endgroup$– 0scar ♦Commented May 22, 2019 at 13:42
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1$\begingroup$ @0scar Yeah, my test part is still functional after going through the autoclave but it warped enough that I don’t think it would remain useful after multiple cycles. I wish I could print aluminum! $\endgroup$ Commented May 22, 2019 at 13:48
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$\begingroup$ TIL POM is a low-print-temp solution for high-temp parts, wow. Seems, like TPU which is also a candidate but flexible, it's a glass way below room temp and transition isn't relevant. $\endgroup$ Commented May 24, 2020 at 13:08
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You need to order the part printed by an SLA machine in PA, preferably with 10 % mineral or glass content. The heat deflection temperature is suitably high for any autoclaving you'll do, and the material will resist most every that your lab and throw at it. I also went down this road with a part for my own lab and found no reasonable solution from a consumer level FDM printer.
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3$\begingroup$ You might want to tell people what PA is, and what additive manufacturing technologies it is used with. And that its heat deflection temperature is under 100 ºC, so only simple shapes will live up to repeated autoclaving. $\endgroup$– DavoCommented May 22, 2020 at 15:51
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$\begingroup$ PA is Polyamid, aka Nylon. SLA Printed Polyamid is generally not auoclaveable due to the structure: it is not solid but porous and soaks in water. $\endgroup$– TrishCommented May 22, 2020 at 22:12