The best starting point for PETG filament is 250 °C on the nozzle and 70 °C on the bed. The safe working range is 240–260 °C for the nozzle and 60–80 °C for the bed — which covers practically every PETG on the market, including Porima PETG. Add 100 % cooling, a speed of 30–80 mm/s and a dry spool. The rest of this guide explains how to get from that starting point to the settings that are ideal for your printer and your model.
PETG is a forgiving material in terms of strength, but a very sensitive one in terms of temperature. A difference of 10 °C can turn a clean print into a web of strings, and a strong part into one that delaminates under its first load. That is why it is worth spending one hour on calibration instead of printing "almost right" for a whole year.
PETG starting settings — the table
The values below come from the Porima PETG technical data sheet and work on the vast majority of FDM printers. Treat them as a point of departure, not as dogma — every printer measures temperature slightly differently.
| Parameter | Value | Comment |
|---|---|---|
| Nozzle temperature | 240–260 °C | Start: 250 °C |
| Bed temperature | 60–80 °C | Start: 70 °C |
| Cooling | 100 % | From the second layer |
| Print speed | 30–80 mm/s | Start: 50 mm/s |
| First layer speed | 15–20 mm/s | Slow and precise |
| Retraction — direct drive | 0.8–1.5 mm | at 30–40 mm/s |
| Retraction — bowden | 4–6 mm | at 30–40 mm/s |
| Flow | 92–98 % | PETG likes slight under-extrusion |
| Layer height | 0.15–0.28 mm | for a 0.4 mm nozzle |
| Drying | 2–4 h at 30–40 °C | manufacturer's recommendation |
| Enclosed chamber | Not required | but does no harm |
You will find the complete set of values for all our materials in the temperature table — it is worth keeping open in a second tab during your first calibration.
Why PETG needs a higher temperature than PLA
PETG is glycol-modified polyethylene terephthalate — the same family of plastic that water bottles are made from. It has a noticeably higher softening temperature than PLA and a much higher viscosity when molten. Pushing it through a 0.4 mm nozzle at a sensible speed simply requires more heat energy.
The second difference matters just as much: PETG crystallises more slowly. PLA sets almost immediately after leaving the nozzle, which is why it forgives fast movements and weak cooling. PETG stays plastic for much longer — hence the characteristic stringing, and hence the need for strong cooling despite the high nozzle temperature. It is an apparent contradiction that confuses many people moving over from PLA: we heat harder, but we cool just as hard.
If you are switching from PLA, compare the two profiles — we describe them in detail in our guide to PLA printing temperature. The biggest trap is that PLA settings "almost work" on PETG, so it is easy to accept the result instead of improving it.
Nozzle temperature — how to find your value
The 240–260 °C range is wide for a reason. A sensor in one hotend can read 8–10 °C lower than another at the same actual melt temperature. Add to that the type of hotend, the length of the melt zone, and whether you print at 30 or at 80 mm/s. That is why the only sensible method is a test on your own machine.
A temperature tower in 20 minutes
A temperature tower is a model divided into segments in which the slicer changes the temperature every few millimetres of height. Download a ready-made tower model, load it into your slicer and add a temperature change at the chosen layers — in PrusaSlicer and OrcaSlicer this is the layer modification option, in Cura the ChangeAtZ plugin.
Set the range from 260 °C at the bottom to 235 °C at the top, in 5 °C steps. The print will take 20–30 minutes. Then judge the tower in three categories: layer adhesion (try to snap a segment with your fingers), stringing between the pillars, and the quality of bridges and overhangs. The best segment is usually a compromise — a little above the minimum at which the layers still hold together.
Write the result down. If you change filament colour, go back to the test: pigments and additives genuinely change viscosity. Black and white PETG often need a different temperature than a transparent one from the same series.
Symptoms of a temperature that is too low
Too cold means poor layer welding. The print looks fine, but cracks along the layers under slight pressure — this is the most dangerous fault, because you only see it once the part is in use. Other symptoms are a matte, rough surface, extruder clicking at higher speeds, under-extrusion in thin walls, and clearly worse bridging. If a part looks good but snaps like a cracker, raise the temperature by 5 °C and repeat.
Symptoms of a temperature that is too high
Too hot produces more spectacular symptoms. You get heavy stringing and cobwebs between parts, sharp corners become rounded, the surface turns uneven and "dragged", and overhangs droop. In extreme cases the filament starts to bubble — but that is usually not a temperature issue, it is moisture, which is covered below. There is also a characteristic faint, sweetish smell at 265 °C and above. That is your signal to come back down.
Bed temperature and the first layer
PETG sticks to the bed willingly — sometimes far too willingly. At 70 °C on PEI, on glass with glue, or on a magnetic sheet, the first layer holds without any trouble. If you are using bare glass, go up to 80 °C and add a thin layer of glue stick as a release agent.
The nozzle-to-bed gap is critical. PETG needs slightly more clearance than PLA. A first layer squashed too hard does not just look bad — it leaves a permanent mark on the build surface. If your PETG first layer looks crushed after using PLA settings, raise the Z offset by 0.02–0.04 mm.
Watch out for PEI — PETG bonds too strongly
This is the most commonly omitted piece of information in printing guides. On a smooth PEI sheet, PETG can bond to the surface so strongly that removing the print tears off a chunk of the coating. The sheet is permanently damaged after that.
There are three ways to avoid it. First: apply a thin layer of glue stick — it acts as a release agent, not as an adhesive. Second: use a textured PEI sheet instead of a smooth one; the smaller contact area is quite enough for PETG. Third: drop the bed to 60–65 °C and let the sheet cool completely before removing the model — PETG releases by itself at around 30 °C. Never pry a PETG print off a warm sheet with a spatula.
Cooling — how many per cent, really
The Porima PETG data sheet says 100 %, and that is the right answer for most applications. There is a widespread belief that PETG "does not like cooling" — a relic of the days when printers had weak fans and one-sided cooling caused warping. On a modern printer with circumferential cooling, full airflow gives noticeably fewer strings, sharper detail and better overhangs.
There are two exceptions. The first layer — cooling off, always, without exception. And parts that need maximum mechanical strength: for those, drop to 40–60 %, because less cooling means better layer welding. It is the classic trade-off: looks versus strength. For brackets, mounts and structural parts it is worth sacrificing a little aesthetics.
Speed, flow and retraction
The 30–80 mm/s range is realistic, but not linear. The faster you print, the more heat the hotend has to deliver per unit of time. At 80 mm/s set the nozzle closer to 260 °C, at 30 mm/s closer to 240 °C. If you raise the speed without raising the temperature, you will get exactly the same symptoms as with a temperature that is too low — weak layers and under-extrusion.
Set flow to 92–98 %. PETG "swells" after leaving the nozzle more than PLA does, so at 100 % it is easy to end up with excess material on the outer walls and a rough top surface.
Retraction is your main weapon against stringing. On direct drive, start at 1 mm at 35 mm/s; on a bowden setup, at 5 mm at 35 mm/s. Turn on combing (avoiding empty space during travel moves) and raise travel speed to 150–200 mm/s — the less time the nozzle spends hanging over a void, the less material escapes. Do not increase retraction indefinitely: above 2 mm on direct drive you start pulling molten material into the cold zone and clogging the hotend.
Moisture ruins even the best-tuned temperature
PETG is hygroscopic — it absorbs moisture from the air. A spool left out in the open for two weeks can take on so much water that no temperature setting will save the print.
The symptoms are unmistakable: crackling and popping at the nozzle, fine bubbles in the extruded strand, a matte surface instead of a glossy one, and stringing that no amount of retraction will remove. If a temperature tower test gives a bad result along its entire length, the problem is not the temperature — it is moisture.
Porima recommends drying for 2–4 hours at 30–40 °C. That is a cautious setting, safe for the spool — a longer session at a lower temperature carries no risk of deforming the plastic core. After drying, keep the spool in an airtight container with a desiccant. Dry filament is a precondition for calibration — there is no point tuning temperature on wet material.
Transparent PETG — different settings
Transparent versions behave differently and need their own profile. Porima PETG Transparent works in a lower range: nozzle 220–250 °C, bed 70–80 °C, cooling 50–100 %, speed 20–50 mm/s.
The reason is optical, not mechanical. Transparency depends on how well the layers merge into one another and how few micro-voids are left in the cross-section. Slower printing, a lower temperature and weaker cooling give the material time to level out and close up bubbles. On top of that, for transparent parts increase layer height to 0.28–0.3 mm and reduce the number of walls — fewer boundaries between layers means more light.
Settings for popular configurations
The type of printer changes the starting point more than the brand of filament does.
| Configuration | Nozzle | Bed | Retraction | Notes |
|---|---|---|---|---|
| Bowden, open frame | 245–255 °C | 70–80 °C | 4–6 mm | Shield it from draughts |
| Direct drive, open frame | 240–250 °C | 65–75 °C | 0.8–1.5 mm | The easiest start |
| CoreXY, enclosed chamber | 250–260 °C | 70–80 °C | 0.8–1.2 mm | Open the lid — PETG does not need chamber heat |
| Printer with an AMS / CFS system | 250–260 °C | 70–80 °C | factory setting | The filament must be dry or it jams the feeder |
On printers with an enclosed chamber it is worth opening the lid for PETG. The material does not need a raised ambient temperature, and a hot chamber reduces cooling efficiency and makes stringing worse.
The most common mistakes
Carrying over a PLA profile unchanged. Result: layers do not bond and the part cracks under its first load. PETG needs roughly 40 °C more on the nozzle.
Turning off cooling "because PETG does not like it". Result: stringing, drooping overhangs, blurred detail. Turn cooling off on the first layer only.
Fighting stringing with retraction alone. If the strings do not disappear after two or three attempts, the cause is usually moisture or too high a temperature, not the retraction settings.
Printing PETG on bare, smooth PEI. Result: the sheet coating is torn off when you remove the model. Always use a release agent or a textured sheet.
Removing the print from a warm bed. Wait until the sheet cools below 30 °C — the model will come off by itself.
Calibrating on wet filament. Dry the spool before the temperature tower test, otherwise you are measuring noise, not signal.
Frequently asked questions
What is the optimal PETG printing temperature?
The optimal nozzle temperature for PETG is 240–260 °C and the bed 60–80 °C. The best starting point is 250 °C on the nozzle and 70 °C on the bed. Determine the exact value for your printer with a temperature tower, because sensors in different hotends can differ by 10 °C.
Does PETG need cooling?
Yes. Contrary to popular belief, PETG prints better with cooling set to 100 % — it gives less stringing and sharper detail. Turn cooling off on the first layer only, and reduce it to 40–60 % for parts that need maximum strength.
Why does PETG string despite correct retraction?
The most common cause is moisture in the filament, not the retraction settings. Dry the spool for 2–4 hours at 30–40 °C, then lower the nozzle temperature by 5–10 °C and raise travel speed to 150–200 mm/s.
Does PETG need an enclosed chamber?
No. PETG barely warps at all and prints without trouble on an open printer. On printers with an enclosed chamber it is actually worth opening the lid, because hot air weakens cooling and makes stringing worse.
At what temperature should PETG be dried?
Porima recommends drying for 2–4 hours at 30–40 °C. That setting is safe for the plastic spool. After drying, store the filament in an airtight container with a desiccant.
Summary
Start at 250 °C on the nozzle, 70 °C on the bed, 100 % cooling and 50 mm/s. Print a temperature tower, pick the best segment and save the profile under the filament name and colour. Dry the spool if it has been sitting open for more than a week. Those four steps take under an hour and solve the vast majority of problems people blame on the material.
You will find all our PETG filaments — standard and transparent — in the PETG category. Each one lists a full print profile in its product description, so you never have to guess the starting point.