Warping

Warping is a part lifting off the bed at its corners or edges as it cools and shrinks unevenly. On a bed a metre across it is the most common quality problem there is, and the size is part of why: the magnitude scales with the footprint, so a few millimetres of lift across a large flat base is not unusual.

What drives it

• The material. Of the two polymers the G1 is supported on, PETG warps more than PLA, and filled and recycled grades more than virgin. Polyolefins like PP warp far more again, which is one reason they are a purging material here rather than a printing one
• The bed. A heated bed is essentially required. Glass gives the cleanest underside, but only with the bed heated for the whole print
• PLA and heat. If the bed runs too hot for too long, PLA does not stick better — it whitens, degrades and lifts. With several solid bottom layers the material never gets time to cool. Lower the bed if PLA first layers go milky or curl; do not raise it. See Bed heater

The levers, in order

Lever	What to do
Bed temperature	Whatever the profile for the grade sets — see Material profiles. Not higher for PLA
Adhesion	The right coat for the material: Bed adhesion sprays
Brim	Inner and outer brim on large flat parts, several lines of each — it is what holds the corners
First layer	Over-extrude it slightly, +10–15% flow on the first layer. It bonds harder, and it helps most with recycled pellets
Geometry	Large flat footprints warp most. Fillet sharp corners; add a slight inward curve to a long flat base; a thicker line width (8–10 mm) gives a stiffer base
Draughts	Keep cold air off big parts. The enclosure add-on exists for exactly this — it holds the chamber temperature so a tall part does not cool faster on the side facing the room
Dry material	Recycled pellets in particular: Starting the dryer

Cooling on the G1 is still being developed

The fan settings in the shipped profiles are not finished, and the PETG ones are not active at all. Two things to know before reaching for the fan: the fans do essentially nothing below 50%, and by 70% they are already very aggressive. There is little useful range between, and too much airflow cools the bed and the nozzle rather than the part — which shows up as a heater fault, not as a cooling problem.

Top layers bowing up

The other end of the same physics, on tall parts: the top is not flat and the last layers rise at the edges. The layer below is still too soft when the next one lands, and gets pushed up.

• Raise the minimum layer time in the slicer, so each layer has time to set
• Drop the extrusion temperature 5–10 °C for the final layers
• The fan is the obvious lever and the one to be careful with — see the caution above

Related notes

• Print quality — which page
• Bed heater — why hotter is worse for PLA
• Bed surface — surfaces and release agents
• Bed adhesion sprays
• Z offset and first layer — the first layer has to be right before any of this