3D Printing materials that do not need an enclosure
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Most printers people buy are open-frame, with no box around them. So a fair question before you load a spool is simple: can I print this without an enclosure? The good news is that the most useful, most common materials work fine in open air. You only need an enclosure for a specific group of harder materials.
This guide lists the materials that do not need an enclosure, explains why they are fine without one, and shows how to get clean prints on an open printer.
What an enclosure actually does
An enclosure is just a box that traps heat around the print and blocks drafts. It does two jobs. First, it keeps the air warm and still, which stops parts from warping and layers from splitting. Second, it helps contain fumes from materials that give them off.
Here is the key idea. When hot plastic cools, it shrinks. If the bottom of a print is stuck to a warm bed while the top cools fast in cool room air, the two ends pull against each other. That tension can lift the corners off the bed (warping) or pull layers apart (splitting). The more a material shrinks as it cools, the worse this gets, and the more it needs a warm, still enclosure to cool slowly and evenly.
So the rule of thumb is short: materials that print cool and shrink little do not need an enclosure. Materials that print hot and shrink a lot do.
The materials that do not need an enclosure
PLA - the easy champion
PLA is the safest open-air material there is. It prints at a low temperature and barely shrinks, so warping is rarely an issue. It also has almost no smell. This is why it is the beginner default and the go-to for most display and hobby prints.
All the PLA variants behave the same way, so PLA+, silk, matte, glow-in-the-dark, and wood-fill PLA are all fine with no enclosure.
PETG - the tough all-rounder
PETG is the step up for functional parts, and it also prints fine in open air. It shrinks more than PLA, so on very large flat prints you may see a little corner lift, but for normal parts it does not need an enclosure. Good bed adhesion is usually all it takes. PCTG, a tougher cousin of PETG, prints in open air too.
TPU - the flexible one
TPU, the rubber-like flexible filament, prints at a low bed temperature and does not warp much, so no enclosure is needed. It is slow and a bit fiddly to feed through the printer, but the lack of an enclosure is not the hard part.
Carbon-fiber PLA and PETG
Composite filaments based on PLA or PETG, like CF-PLA and CF-PETG, print in open air just like their base material. One warning that has nothing to do with enclosures: the carbon fiber is abrasive and wears out normal brass nozzles, so you need a hardened steel nozzle for any carbon-fiber filament.
The materials that do need an enclosure
So you know what to avoid on an open printer, here are the ones that really want a box. These shrink a lot as they cool, print hot, or give off fumes:
- ABS - warps badly and gives off fumes. An enclosure is close to essential.
- ASA - behaves like ABS, so it wants an enclosure too, even though it is made for the outdoors.
- Nylon - warps and also needs to be kept dry, so an enclosure helps on both counts.
- Polycarbonate - prints very hot and warps hard, so it needs a sealed, heated enclosure.
- Carbon-fiber Nylon or PC - same as their base materials, so an enclosure is needed.
You can sometimes get small ABS or ASA parts to print on an open machine in a warm, draft-free room, but it is a fight. For anything sizable, these belong in an enclosure.
One catch: an enclosure can hurt PLA
It is worth knowing that the box is not always a bonus. PLA likes to be cooled while it prints, and it does not enjoy sitting in hot, trapped air. In a warm enclosure, PLA can suffer heat creep, where heat travels up into the feed path and softens the filament before it should, causing jams. So if you have an enclosed printer, you may actually want to leave the door open for PLA. More enclosure is not always better.
Quick reference
| Material | Enclosure needed? | Why |
|---|---|---|
| PLA (and variants) | No | Prints cool, barely shrinks |
| PETG / PCTG | No | Low warp; just needs good bed adhesion |
| TPU | No | Low bed temp, low warp |
| CF-PLA / CF-PETG | No | Same as base; use a hardened nozzle |
| ABS | Yes | High warp and fumes |
| ASA | Yes | High warp and fumes |
| Nylon | Yes | Warps and must stay dry |
| Polycarbonate | Yes | Very high temp and heavy warp |
How to get clean prints without an enclosure
Even with easy materials, a few habits keep open-air prints reliable:
- Kill the drafts. Keep the printer away from open windows, doors, and fans. A sudden cool breeze on a print is the main thing an enclosure protects against, so mimic it by keeping the room still.
- Keep the room reasonably warm. A cold garage makes even PLA and PETG more likely to lift. Room temperature is fine; cold is not.
- Nail the first layer. A clean, level bed and a good first layer fix most adhesion problems. Use a brim on large or tall parts for extra grip.
- Use the right bed surface. A clean PEI or textured plate grips PLA and PETG well. Wipe off grease, since fingerprints ruin adhesion.
- Tune cooling per material. PLA likes lots of part cooling. PETG likes a bit less. TPU likes some. Follow the filament brand's guidance.
Enclosure FAQ
Do you need an enclosure for PLA?
No. PLA prints cool and barely shrinks, so it is the easiest open-air material. In fact, a hot enclosure can cause jams with PLA, so if your printer is enclosed you may want to leave the door open for it.
Does PETG need an enclosure?
No. PETG prints fine in open air. It shrinks a little more than PLA, so on very large flat parts you might see minor corner lift, but good bed adhesion and a brim handle that. No box required.
Which materials must have an enclosure?
ABS, ASA, Nylon, and Polycarbonate really want one, because they warp a lot, print hot, or give off fumes. Carbon-fiber versions of Nylon and PC need one too. You can sometimes print tiny ABS or ASA parts open in a warm, still room, but it is not reliable.
Can I print flexible TPU without an enclosure?
Yes. TPU prints at a low bed temperature and does not warp much, so no enclosure is needed. The tricky part with TPU is feeding it smoothly, not the temperature.
Will an enclosure improve my PLA prints?
Usually not, and it can make them worse. PLA wants cooling as it prints. Trapped hot air can soften the filament too early and cause clogs. Save the enclosure for materials that shrink a lot, like ABS and ASA.
Need a part in a material your printer can't handle?
If a job really needs ABS, ASA, Nylon, or another enclosure-only material and your open printer is not set up for it, you do not have to buy new gear. Latencot's custom 3D printing service prints in the right material for the job, enclosure and all. Send us the file and tell us where the part will live, and we'll handle the rest.