Good filament/s for heat resistance in cars

Question

I have designed a cupholder for my center console in my truck with PETG. I was hoping it wouldn't deform and it didn't for a while but we got some high temperatures the past few days (around 32-38 °C or 90-100 °F).

Kind of figured it wouldn't hold up mid-summer but I was wondering if ABS would be my next best choice or if there is something better for this. It does see some sunlight but not a lot.

I do want to start producing some to sell and don't want it deforming in high-temperature areas. Also, I have an Ender 3 Pro so I can't do super crazy filaments.

Answer 1

ABS, or preferably ASA which is "a better ABS", is probably your main option. ASA holds up better under UV/sunlight and is easier to print (less warping). Like ABS it should be printed with ventilation, and benefits some from an enclosure but can be done without it or with a primitive one (cardboard box).

A second strong candidate would be real PET (not PETG). It's hard to find as filament nowadays, and might still not have the heat resistance you want fresh off the printer, but it can be annealed with only minor dimensional changes to drastically increase heat resistance to 100 °C or higher. Strictly speaking, you can do this with PLA too, but it's hard to get it not to deform horribly when annealing unless you use 100% infill and pack it in sand or salt or something while annealing. Note that you cannot do this with PETG; it has been specifically and intentionally modified (vs normal PET) not to be able to crystallize (anneal), and to lower the temperaturse at which it softens and melts.

Another great option would be TPU. It's not subject to a glass transition temperature above room temperature (my understanding is that technically its $T_g$ is very very cold, but that may be a misunderstanding) and does not really warp/deform permanently until you reach temperatures near what you could print it at. I've used it as a mold for melting crayons in an oven at 175 ˚F (80 ˚C) with no problem. Depending on your perspective it could be easier or harder than ABS to print. If your extruder is bad at handling flex materials you might have to go really slow, or you might have trouble with jamming on retraction, but unlike ABS it has no heat/warping issues while printing and can be done even on a cold bed, and does not particularly need ventilation (although as always, be careful if you have pet birds around).

Note that while TPU is considered a "flex" material, it can be fairly rigid at high infill with rigid infill patterns like triangles or cubic, or printed 100% solid, especially if you go with harder variants. 95A is typically the highest you see but sometimes you can find 98A.

Answer 2

If you don't need it to be super precise, nothing beats annealed HTPLA. If you keep it on the bed while annealing you can minimize warping and you'll get a part that can take up to 180 °C. Fusion filaments makes a great HTPLA+ that's reasonably cheap, and you can get it without a spool. Their reusable spool is on Thingiverse. Just don't keep it on the bed if you have a magnetic bed. HTPLA needs over 80 °C which will ruin a magnetic bed.

Answer 3

Personally, I'd get the design just right and then I'd use the "Get an Instant Quote" option on the "Solutions" menu at shapeways.com . It'll be expensive, but you could have it printed in sintered powdered stainless steel or aluminum. You'll want to design as many voids into it as you can, because they charge by the gram. There are cheaper vendors and you may have one locally, especially if you tell them "totally not a rush job" and they can run it with other parts.