Key takeaways
- A chamber doesn't lift the part above its glass transition. It slows cooling and reduces the temperature gap between the new layer and what's already printed — that's all it does, and it's enough to change the outcome.
- The deciding threshold is part size, not material name. The same ABS spool gives a good 60 mm part on an open printer and a warped 200 mm part on the same printer.
- Passive and actively heated chambers differ by about 20 °C. For PC and PA6-GF, that 20 °C is the whole problem.
- A hot chamber makes PLA and PETG harder to print: the filament softens before the hot end and the extruder starts to slip.
"The printer is enclosed" is used for two very different things: a cover that holds heat, and a chamber with its own heater and sensor. The gap between them is about 20 °C, and that 20 °C decides whether you can print PC.
What a chamber does, physically
An FDM part shrinks as it cools. If the freshly extruded layer cools fast while the part below has already cooled, the two shrink differently and stress builds up in the part. That stress escapes in two ways: the part lifts off the bed, or layers split at corners and ribs.
A warm chamber doesn't soften the part or lift it above its glass transition — ABS's Tg is somewhere above 100 °C, while the chamber sits at 50–60 °C. What it does is reduce the temperature difference between the new layer and the printed part, and slow the cooling. That's all — and that alone takes a 200 mm ASA part from warped to flat.
Three levels, and what each buys
| Level | Chamber temperature | Example printers | Prints well up to |
|---|---|---|---|
| Open frame | Room temperature | Bambu Lab A1, Prusa MK4S (no enclosure) | PLA, PETG, TPU, small PA12 parts |
| Passive enclosure | ≈ 35–45 °C with the bed at 100 °C | Printers with a factory cover, or a home-made one | ABS and ASA up to about 150 mm; medium PA-CF parts |
| Actively heated chamber | 55 °C (Prusa CORE One+) · 60 °C (Creality K2 Plus) · 65 °C (QIDI Plus 4, Bambu Lab H2D) | Engineering-class printers | PC, PA6-GF, large ABS/ASA, tall thin parts |
Compare this table with the chamber settings ZORVA publishes for each material and one detail stands out: ASA needs 50–60 °C and PC needs 50–60 °C, so a chamber topping out at 55 °C sits in the lower half of that range. It prints, but with no headroom for large parts. A 65 °C chamber has it.
The real threshold is part size
"ABS needs an enclosure" is half right. Shrinkage force accumulates with length: the wider the part, the greater the total shrinkage between its ends, and the harder it pulls the first layer off the bed. A 50 mm ABS block prints fine on an open printer in a draught-free room. The same material at 200 mm lifts at the corners.
Practical thresholds by longest dimension
- Under 80 mm
- Open printer, shielded from draughts. ABS and ASA usually still give usable parts.
- 80–150 mm
- Passive enclosure. This is the range a home-made cover solves.
- 150–250 mm
- Heated chamber. A passive one gives warped parts or split ribs.
- Over 250 mm in engineering materials
- Heated chamber plus redesign: split the part, add fillets, reduce thick sections.
The price of a hot chamber
A warm chamber isn't free, and this is the part sales pages leave out. PLA printed in a 50 °C chamber is prone to softening above the hot end: the filament swells in the feed path, the extruder slips, and the print stops partway through from under-extrusion. PETG strings more. That's why heated-chamber printers all let you switch the heat off and open the door — and you should do exactly that for PLA.
- PLA and matte PLA — door open, heater off, fan at 100 %.
- PETG — a lightly warm chamber is optional; don't exceed 40 °C unless you need to.
- TPU — no heat. What TPU needs is a short filament path, not warmth.
- ABS, ASA, PA, PC — door shut, heat on to the level in the catalogue settings.
Enclosures and the air you breathe
An enclosure does two things at once: it holds heat, and it holds most of the fine particles and volatile compounds released while printing. That's good — until you open the door the moment the print finishes and take the whole lot in the face. ABS gives off styrene when printed, so for ABS, ASA and PC, ventilation is mandatory, not optional. How to do it properly is in 3D printing fumes and ultrafine particles.
An enclosure isn't a premium feature. It's what lets a whole family of materials exist outside a lab.
Building your own cover: what works and what not to do
- 01
Block draughts before you hold heat
Most failed ABS prints in a hot climate aren't from too little chamber heat but from a printer sitting under the air conditioner or beside a fan. Simply moving it out of the airflow and screening three sides with cardboard makes a difference. This step is free.
- 02
Use a cover, keep flammables away from hot parts
Acrylic panels or a purpose-made fabric cover both work, as long as nothing touches the bed, hot end or wiring. Don't enclose the power supply and controller: they need cooling, and many printers put the board right under the bed.
- 03
Don't fit your own chamber heater
A proper chamber heater has a sensor, over-temperature cut-off and designed airflow. A home-fitted heater without those three is an ignition source next to several hundred grams of plastic. If you need real chamber heat, change the printer rather than modify it.
- 04
Measure before you trust it
Once the cover is on, measure the chamber while printing with the bed at its real temperature. If you can't get above 35 °C, the cover isn't doing its job — and you're solving a different problem from the one you think.
To check whether your current printer reaches the material you need, read what can my 3D printer print. If your part still warps with enough chamber heat, the cause is usually settings or design — the troubleshooting guide goes symptom by symptom.
Frequently asked
Can I enclose the printer in a cardboard box?
For holding heat, yes, and it's the cheapest way to test whether your part needs a chamber at all. But cardboard burns: keep it away from the bed, hot end and power cables, and don't run the printer overnight in a closed carton. If it works, move to acrylic panels or a printer with a built-in chamber.
Does a hot chamber make parts stronger?
Yes, by a fairly indirect route: slower cooling gives layers more time to fuse, so strength across the layers improves. It's the same mechanism as raising nozzle temperature in print settings for strength. Don't make the trade with PLA: you'll lose more to extruder slip.
What is a printer with a cover but no heater?
A passive enclosure. It holds the heat the bed gives off and usually settles at 35–45 °C with the bed at 100 °C, depending on the room. Enough for medium ABS and ASA parts, not for PC or PA6-GF. It's the most common class of printer at the budget end.
Why does PC still delaminate with a 60 °C chamber?
Usually wet filament rather than the chamber. PC absorbs moisture fast, and below 260 °C its layers don't bond enough. Dry it at 80 °C for 8 hours, feed from a heated dry box during the print, and run the nozzle in the upper half of its 265–300 °C window. The drying routine is in how to dry filament.
My room is already 33 °C — do I still need a chamber?
Yes, and this is a common mistake. A chamber deals with temperature gradients and draughts, not just the base temperature. A 33 °C workshop with a ceiling fan still lifts the corners of an ASA part that prints fine in a still 45 °C enclosure. The real advantage of a hot climate is that you need less heat to reach the threshold, not that you can skip the chamber.