Best Cura settings for PETG: what we actually use in the workshop

PETG is a great filament once you have it dialled in. It is tougher than PLA, handles a warm car in summer, and bonds layers like glue. The trade-off is that it strings, it sticks to the bed a bit too well, and it punishes you for the same settings that make PLA look perfect.

Here is the Cura profile we actually load on the bench, plus the reasons behind each number. Treat them as a starting point. Every spool is slightly different, and you will still want to run a temperature tower on a fresh brand.

A Cura starting profile for PETG

These values assume a direct-drive or well-tuned Bowden machine with a 0.4 mm nozzle on a PEI or glass bed. Adjust from here, do not copy blindly.

1. Print temperature: 235 deg C for the first layer, 230 deg C after. Drop in 5 deg C steps if you see stringing, raise it if layers split. 2. Bed temperature: 75 deg C for the first layer, 70 deg C after. Smooth PEI likes the lower end, textured PEI is happy at 75. 3. Layer height: 0.2 mm. PETG looks tidy at 0.2 and hides small inconsistencies that show up at 0.12. 4. Print speed: 45 mm/s for walls, 50 mm/s for infill, 25 mm/s for the first layer. PETG hates being rushed. 5. Initial layer speed: 20-25 mm/s. Slower means a fatter, better-anchored first layer. 6. Retraction distance: 5 mm for Bowden, 1.5 mm for direct drive. Anything more on direct drive and you will grind filament. 7. Retraction speed: 25 mm/s. Faster than this on PETG and you snap strings off inside the hotend. 8. Z-hop when retracted: 0.2 mm. Stops the nozzle smearing across the top of the print. 9. Cooling fan: 30 percent after the first three layers, never 100 percent. PETG needs the heat to bond. 10. Flow rate: 95 percent as a starting point. PETG over-extrudes more visibly than PLA. 11. Combing mode: "Not in skin". This is the single biggest fix for stringing on visible top surfaces. 12. Wall line count: 3. PETG is a structural filament; give it walls to be structural with.

Save that as a custom profile so you can come back to it. Cura's stock "Generic PETG" profile is too hot and too fast in our experience.

Why PETG strings, and the Cura settings that actually help

Stringing happens because PETG stays soft and sticky for longer than PLA after it leaves the nozzle. When the head moves between two features, molten plastic keeps weeping out and leaves a wispy trail.

The fix is not just "more retraction". On most printers, more retraction past about 6 mm causes its own problems: the filament cools inside the heatbreak, the next extrusion is under-pressured, and you get a blob exactly where you were trying to avoid one.

What works for us, in order:

• Drop the temperature 5 deg C at a time. A temperature tower from 245 down to 220 will show you the sweet spot in twenty minutes.
• Set Combing Mode to "Not in skin" or "Within infill". This keeps travel moves inside the print where strings cannot be seen.
• Enable Coasting at around 0.064 mm cubed. It tells Cura to stop extruding just before the end of a line and use the residual pressure.
• Slow the outer wall down to 30 mm/s. Slower walls give the filament time to settle without dragging.
• Make sure your filament is dry. Wet PETG sounds like bacon frying in the hotend and strings no matter what you do.

If you have tried all of the above and the print is still hairy, the spool is the suspect, not the slicer. PETG soaks up moisture from the air within days.

Bed adhesion: the opposite problem

PETG sticks to bare glass and PEI hard enough to take chunks out of the bed. We have had to replace customer build sheets after a single first-layer-too-low print.

Use a release layer. A thin wipe of Magigoo, a glue stick, or even hairspray will keep PETG bonded during the print and let it pop off cleanly when the bed cools.

If your first layer is lifting at the corners instead, the bed is too cold or the part-cooling fan came on too early. Push the bed to 80 deg C, hold the fan off until layer four, and add a brim of 5 mm.

Cooling: less than you think

PLA wants the fan on full. PETG does not. Run the part-cooling fan above 40 percent and your layers will split when you flex the part. We use 30 percent for general work and bump to 50 percent only when bridging or printing fine detail.

The first three layers should always be 0 percent fan. PETG needs that heat to weld itself to the bed.

Can I just use the default Cura PETG profile?

You can, and for a quick functional print it will probably work. We do not use it because it sets the fan high, the temperature high, and the speed high. That gets you stringing, poor layer bonding, and a part that looks rougher than it should.

Fifteen minutes spent making your own profile, with the numbers above, will save you hours of failed prints later.

Is PETG worth the hassle over PLA?

For decorative prints, no. PLA is easier, sharper, and cheaper.

For anything that lives outdoors, sits in a car, holds a load, or gets handled a lot, PETG is the right call. It does not get brittle with age the way PLA does, it survives a summer windowsill, and it bonds layers strongly enough to be genuinely useful as a structural part.

When to mail it in

If you have tried a temperature tower, dried the filament, tweaked retraction, and your PETG prints are still rough, the issue is usually mechanical: a worn nozzle, a partially clogged heatbreak, a loose extruder gear, or moisture you cannot get out at home. We can diagnose all of those on the bench, swap parts, and send you back a tuned printer with a known-good PETG profile saved to it. We also run mail-in PETG printing if you would rather we print the part for you. Send a description and a photo of a failed print through /contact.html and we will tell you what is worth doing before you post anything.