ABS warping on the Bambu Lab P1S: causes and fixes

To stop ABS warping on a Bambu Lab P1S, wash the build plate with dish detergent, add glue and raise the bed to its 100 °C maximum. Keep the door and glass lid closed with the auxiliary fan at 0%, warm the closed chamber before printing, and put brim ears on sharp corners. ASA takes the same fixes.

Why does ABS warp on the Bambu Lab P1S?

ABS warps on a Bambu Lab P1S because its edges cool and shrink faster than its center, and that tension pulls the corners off the plate. The P1S has no chamber heater, so the only heat around the part comes from a bed that tops out at 100 °C. Dirty plates, drafts and fan airflow make it worse.

Bambu Lab’s filament guide says ABS, ASA, PC and PA “require higher heatbed and chamber temperatures to suppress warping.” Its Bambu ABS and Bambu ASA data sheets list a 45 to 60 °C chamber. The P1S can neither heat nor measure its chamber. Bambu Lab says the P1 series cannot take its chamber heating unit. The P1S spec sheet lists no chamber temperature sensor, and Bambu Studio’s P1S device file turns the chamber temperature display off.

How to stop ABS warping on a Bambu Lab P1S

1. Wash the plate. Scrub it with a sponge, warm water and a dish detergent free of oils and moisturizers. Rinse and dry it, then handle it by the edges. Bambu Lab calls skin oils “the #1 cause” of bed adhesion failure. On the Bambu Textured PEI Plate, it warns that alcohol can spread the oil and that acetone damages the plate.
2. Fit an ABS-rated plate and select it in Bambu Studio. Bambu Lab lists the Textured PEI, Smooth PEI (High Temperature) and Engineering plates for ABS and ASA, and not the Cool Plate. A mismatched plate type sets the wrong bed temperature. On the Textured PEI Plate it also skips the 0.04 mm lower first layer that the start G-code sets for that surface. Which Bambu plate to use for ASA compares the plates.
3. Add glue. Bambu Lab’s ABS and ASA data sheets list glue as the bed preparation. Spread a glue stick thin and even. With Bambu Liquid Glue, Bambu Lab found four even coats hold best and that extra layers hold less.
4. Raise the bed to 100 °C. Bambu Lab says to add 10 to 15 °C when ABS or ASA corners lift. The Bambu ABS profile prints at 90 °C, so set the filament’s plate temperature to 100 °C for every layer. That is the top of Bambu Lab’s 90 to 100 °C range and the P1S bed’s limit. Bambu ASA already prints at 100 °C.
5. Keep the auxiliary and chamber fans off. The Bambu ABS and Bambu ASA profiles already set both off on a P1S (values below). With a custom profile, set the auxiliary part cooling fan to 0% on its Cooling tab.
6. Add brim ears or a brim. In Bambu Studio, set the object’s Brim type to Painted and place brim ears on the corners that lift. The Auto brim also works, and Bambu Lab says it comes out wider for ABS.
7. Change the infill on big, flat parts. Switch to Gyroid at 25% or less; Bambu Lab says grid and triangle patterns create “internal linear tension.” For structural parts it suggests 5 walls and about 25% infill, and warns against going above 50%.
8. Dry damp filament. Bambu Lab lists crackling, popping and bubbly surfaces as signs of moisture. Its ABS and ASA data sheets give 80 °C for 8 hours in a blast drying oven. Drying filament for a Bambu Lab printer covers oven and on-printer methods.
9. Keep the door and lid closed. Bambu Lab’s filament guide answers “NO” to removing the upper glass cover for ABS and ASA. Keep the printer away from open windows, air-conditioning vents and desk fans, which Bambu Lab says cool one side of a print faster than the other.
10. Preheat the chamber. With the printer closed, heat the bed to 100 °C and wait until a thermometer inside stops rising before you send the print (method below).

How do you preheat a Bambu Lab P1S for ABS?

Fit the glued plate, close the front door and glass lid, then set the heatbed to 100 °C from Controls on the P1S screen and wait before sending the print. Bambu Lab gives no preheat time for the P1S, and the printer cannot read its chamber temperature, so put a thermometer inside and start once it stops rising.

• What to aim for. Bambu Lab’s warping guide says the chamber “should reach 40 °C+” when ABS or ASA corners lift, and the Bambu ABS and Bambu ASA data sheets list 45 to 60 °C. Bambu Lab publishes no figure for what a P1S chamber reaches on bed heat alone.
• Why the print’s own warm-up falls short. Bambu Studio’s P1S start G-code waits only until the bed reaches its first-layer temperature, then homes, wipes the nozzle and levels the bed. It never waits for the air in the chamber.
• Keep it shut until the print ends. Bambu Lab’s warping guide says to block airflow around the printer while it prints, with the front door and top cover closed.

Since Bambu Lab’s chamber heating unit does not fit the P1 series, more heat than the bed gives means a third-party heater. Chamber heaters compares the retrofit kits. Fitting one is outside Bambu Lab’s support and at the owner’s risk.

Should the aux fan be off for ABS on the P1S?

Yes. Bambu Studio’s Bambu ABS and Bambu ASA profiles set the auxiliary part cooling fan to 0%, against 70% for PLA. Bambu Lab’s warping guide says lowering the auxiliary fan can reduce warping. Leave it at 0% for ABS and ASA, and check that a custom or third-party ABS profile does the same.

The table gives the fan values in Bambu Studio’s profiles for a P1S with a 0.4 mm nozzle, as published on GitHub on October 24, 2026. Rows follow the fan order of the P1S spec sheet.

Bambu Studio’s Generic ABS profile also runs the auxiliary fan at 0%. Bambu Lab’s tip to lower the auxiliary fan to about 40 to 50% is for profiles that use it, such as PLA.

On a P1S the auxiliary fan spins briefly during the start routine, which the G-code labels “to cool down toolhead”, and stops before the first layer. The same start G-code switches off the chamber fan, which Bambu Lab says removes hot air from inside the printer.

The ABS profile’s exhaust fan setting (70%) is sent only to printers Bambu Studio marks as supporting air filtration. The P1S is not one of them, so its chamber fan stays off unless you turn it on yourself.

Why won’t ABS stick to the P1S build plate?

If the first layer will not stay down at all, the problem is adhesion, not warping. Bambu Lab’s quick fixes are to re-run automatic bed leveling, check that the first layer is squished into the plate rather than sitting on it, and confirm the plate type selected in Bambu Studio. Then wash and glue the plate (steps 1 to 3). If adhesion is still weak, Bambu Lab suggests a 0.5 mm first-layer line width and a 0.25 mm first-layer height.

Is the P1S enclosure enough for ABS?

Yes, by Bambu Lab’s own guidance. Its filament guide names the P1S among the enclosed printers recommended for ABS and ASA, and the P1S spec sheet rates both “Ideal.” The enclosure is passive: it holds the bed’s heat but adds none of its own. The Bambu Lab hub compares the P1S with Bambu Lab’s heated-chamber models. A closed chamber also traps ABS fumes, and P1S ABS ventilation covers the exhaust and filter options.

Does ASA warp the same way on the P1S?

Yes. Bambu Lab groups ASA with ABS, gives both a 90 to 100 °C bed and a 45 to 60 °C chamber, and ranks ASA just below ABS for shrinkage risk. On a P1S, the Bambu ASA profile already runs the bed at 100 °C, so there is no bed temperature left to add. Every other step above applies unchanged.