PLA problems: stringing, warping, heat creep, soft parts

This guide is for PLA prints that string, jam partway through, lift at the corners, droop on overhangs, snap, or bend in the heat. It collects what Bambu Lab, Prusa, Polymaker, ELEGOO, Overture and eSUN say about their own PLA, and keeps each setting to the product or printer the maker names. Our other guides go deeper on each general problem, so this page sticks to what's specific to PLA and links out for the rest. Start here:

What settings do PLA makers give?

Every maker here publishes its own window, and they don't match. The bed figure varies the most, and Bambu Lab and ELEGOO tie it to the plate.

Prusa's own store page for Prusament PLA lists 215 °C and a 50–60 °C bed, inside the Prusament material page's ranges. Bambu's warping guide warns that the plate type in the slicer has to match the plate on the printer. If you slice for the Cool Plate (35 °C for PLA) but print on the Textured PEI Plate, which it says needs 55–65 °C for PLA, "the adhesion temperature will be far too low." eSUN's PLA+ starts warmer than the standard PLAs here. Our PLA vs PLA+ guide covers why a "plus" spool needs its own profile.

Stringing and oozing

Prusa says "PLA is sometimes prone to stringing and oozing - this can be reduced with proper retraction settings." Three makers publish retraction starting points for their PLA:

The other causes the makers name:

• Too hot. Polymaker's clog guide says that if you see "stringing, blobbing, or smoky fumes," lower the nozzle temperature "in small steps (5–10 °C) within the recommended range for the filament."
• Moisture. Bambu's drying guide says moisture that vaporizes in the nozzle leads to "stringing, oozing, holes, rough surfaces, and reduced strength."
• A warm chamber. On the CORE One, Prusa says an open chamber grille matters "since low-temperature filaments might clog the nozzle and cause stringing." See Mid-print jams and heat creep.
• Travel paths. eSUN's PLA+ data sheet suggests turning on Z seam alignment and starting-point alignment, turning off Z-axis lift, avoiding travel through the shell, and lowering print speed "to achieve the best printing effect."

Our stringing guide covers temperature towers, retraction tests and travel settings for any material.

Mid-print jams and heat creep

A PLA print that starts well and then stops extruding may be heat creep: the filament softens too high in the hotend and jams. Prusa notes it is "only one of the ways by which your hotend can clog," so rule out the others too. Bambu says PLA "is the most common filament that gets clogged, as it has the lowest glass transition temperature," and that heat buildup inside the enclosure is "the most common reason" for hotend or extruder clogs on the X1 Carbon and P1S. Prusa says heat creep "usually happens when printing with PLA," and that "printing PLA in a fully closed and unventilated enclosure is very likely to cause problems." Polymaker calls heat creep "especially problematic" with low glass transition materials such as PLA.

On enclosed Bambu Lab printers

Bambu's rule is to keep the chamber "at least 10 degrees lower than the glass transition temperature of the filament." Its PLA Basic data sheet lists a 60 °C glass transition temperature and a 25–45 °C chamber. The practical steps:

• Bed above 45 °C: for filaments that soften below 60 °C, such as PLA, Bambu's filament guide recommends "opening the front door and/or removing the upper glass cover plate." It says this is more necessary in a warm room and less necessary in a cold one.
• X1 series: with the Cool Plate at about 35 °C, you can print PLA with the front door and top cover closed. On the Textured PEI or High-Temperature PEI plate, print PLA "with the front door open and/or the top cover removed."
• P1S: its standard Textured PEI plate needs a 55 °C bed for PLA, so Bambu recommends the door open and/or the top cover off. To print closed, it recommends the Cool Plate at 35 °C. Bambu says the chamber fan turns on for PLA above a 50 °C bed, but in a warm room it "might not be able to keep the temperature inside the chamber low enough."
• P1P: the open-frame P1P needs no changes for PLA. If you enclose a P1P, follow the P1S advice.
• Cold rooms: at 5–10 °C ambient, Bambu says you can close the door and cover for low-softening filaments, and open the door slightly if clogs still happen.

Bambu also says its Cool Plate SuperTack, which holds PLA at a 40 °C bed, "lowers the risk of nozzle clogging when printing PLA and PETG."

On Prusa printers

On the CORE One and CORE One INDX, open the chamber grille for low-temperature filaments. The printer shows a reminder, but Prusa says it "does not sense if the grille is open or not." Prusa's heat creep article, written for its MK2.5 and MK3-family printers, lists a room above 35 °C, or a printer in an enclosure, as a cause. It suggests lowering the bed by 5 or 10 degrees for PLA, with a brim if adhesion suffers.

Our heat creep guide covers fan checks and retraction, and why raising the nozzle temperature makes it worse. To clear the jam itself, see our clog diagnosis guide.

Corners lifting and first layer

The makers rate PLA as low-warping. Prusa says it is "not prone to significant warping," Prusament lists its susceptibility to warping as "None," and Bambu's filament guide lists PLA as "Not prone to warping." When corners do lift, they give these fixes:

• Bambu Lab: raise the bed by 5 to 10 °C, target 55–65 °C on the Textured PEI Plate, and add an 8–10 mm brim. If the first layer won't stick, set "No cooling for first X layers" to 3. Bambu says that in a room below 20 °C, "warping can occur even with PLA and PETG," and that an open-frame printer such as the A1 then needs the bed raised by an additional 10 °C.
• Prusa: "Some materials such as PLA or PETG need a lot of cooling. If corners of your print are lifting up, check if the print fan is enabled, try increasing the print fan speed." Check that the fan works and the shroud isn't blocked or melted.
• Overture: "Increase bed temperature in 5–10 °C steps," slow the first layer, clean the build plate, and use glue stick, Magigoo or a textured PEI surface.
• Prusa, on its Original Prusa i3 sheets: the smooth PEI sheet "works better for printing parts that have a small contact area." On a powder-coated sheet, lower Live Adjust Z so the filament fills the texture, but not too far, "or you will damage your sheet!" If a sheet is already marked, see our PEI sheet damage guide.

Clean the plate, then decide on glue

Prusament's page recommends isopropyl alcohol, or warm water with a few drops of dish soap. Bambu says to wash its plates with dish soap and hot water, and not to use acetone. On glue, the makers differ:

For a print that won't come off, see our print stuck to the bed guide. If PLA won't stick to a textured PEI plate, see our textured PEI guide. For first-layer checks on any material, see our first-layer adhesion guide and our warping guide.

Cooling, details and overhangs

PLA wants strong cooling. Prusament says "Feel free to cool PLA during printing as much as possible," and that with good enough cooling "you can print extreme overhangs and bridge between far away surfaces." Prusament and eSUN set the fan at 100%, and Polymaker's PLA page says "100% cooling for sharp details."

Chamber heat works against this. Bambu says PLA "can benefit from additional cooling during printing, leading to better overhangs," and that in a warm enclosure "the airflow provided by the part cooling fans is hotter," so print quality can suffer even without a clog. Prusa's warping article says "Printing PLA or PETG in an enclosure might not be a good idea," because these materials need a lot of cooling.

The data sheets give these limits:

• Bambu Lab PLA Basic and PLA Matte: maximum overhang angle 55°, maximum bridging length 30 mm, support material "Support for PLA."
• Overture PLA: threshold overhang angle 60°.

Our small details melting guide covers minimum layer time and fan settings, and our overhangs and bridging guide covers the rest.

Brittle parts and weak layers

Some of this is PLA itself. Prusa lists "Brittle and inflexible" as a con and says PLA "breaks along layers or into shards upon impact. Layer adhesion is weaker compared to other materials." Polymaker says basic PLA's low impact resistance "limits functional use."

Each maker's own data shows lower strength between layers (Z) than along them (X-Y):

Each maker tested under its own conditions, so compare X-Y with Z within a row, not between rows. Bambu's data sheets say all specimens were annealed and dried at 55 °C for 8 h before testing. Polymaker's and eSUN's sheets list how their specimens were printed but no annealing step. For a stronger part, Prusament says to "increase the number of perimeters rather than increasing the infill percentage as the majority of a 3D print strength comes from its outer shell." If you need more toughness than plain PLA gives, our PLA vs PLA+ guide covers what each maker's "plus" grade documents. For layers that split, see our layer adhesion guide. For filament that snaps on the spool, see our brittle filament guide.

Why do PLA parts go soft in heat?

No print setting fixes this one. The makers say:

• Prusa: PLA "gets soft and deforms at temperatures over 60 °C." Prusament lists a temperature resistance of 55 °C and says parts "start to lose mechanical strength at temperatures over 60 °C."
• Bambu Lab: PLA is "Not recommended for environments at about 50 ℃ or higher, as it may slowly degrade, soften, and deform."
• Polymaker: PLA "Softens at temperatures above 60°C (e.g., in hot cars)."

The data sheets list heat deflection temperatures of 54 °C (1.8 MPa) for Bambu PLA Basic, 52 °C for Bambu PLA Matte and 58 °C for PolyLite PLA. eSUN lists 53.78 °C for its PLA+ and ELEGOO 57 °C for its PLA, both at 0.45 MPa. Bambu suggests annealing PLA Basic and PLA Matte prints at 50–60 °C for 6–12 hours, but warns "some prints may deform and warp after annealing," and says to use a forced-air oven, not a microwave or kitchen oven. Polymaker lists no annealing setting for PolyLite PLA.

Our parts deforming in heat guide compares these figures with PETG, ASA and other materials.

Drying

The makers disagree on how much PLA needs drying.

Bambu's general filament guide gives PLA 55 °C for 8 h, not the 50 °C on its PLA Basic data sheet, so use the data sheet for the exact spool. Prusa says PLA "doesn't change properties too much by uptaking humidity," but on the multi-tool XL, where idle tools stay heated, "even PLA can absorb enough moisture to create printing issues," so it recommends drying filament before printing on the XL.

Don't overdo the heat. Prusa says not to exceed its drying temperatures, "or the filament will soften and stick together," and warns that home ovens can damage low-temperature filaments such as PLA. Bambu says its AMS static drying mode isn't suitable for PLA, because the layers "may stick together or deform." When you print PLA from an AMS 2 Pro or AMS HT, Bambu lowers the drying temperature to 45 °C. Our wet filament guide covers how to tell if a spool is damp.

A sensible order

1. Load the filament maker's profile, and select the plate you actually have in the slicer.
2. On an enclosed printer, open the door, lid or grille your printer maker specifies for PLA before a long print.
3. Clean the plate the way its maker says. Add glue only where your plate or filament maker calls for it.
4. For lifting corners, raise the bed within range and add a brim, then check the part cooling fan.
5. For stringing, lower the nozzle temperature within range, then tune retraction from the maker's numbers.
6. Dry the spool to its maker's setting if you hear popping or see a rough surface.
7. For a mid-print jam, clear it with your printer maker's procedure, then follow the heat creep checks.
8. If the part will see 50–60 °C or more, switch material rather than tuning PLA.

Checklist

• Nozzle, bed and fan inside the filament maker's ranges.
• The slicer's plate type matches the plate on the printer.
• On a Bambu enclosed printer with the bed above 45 °C, front door open and/or top glass cover off.
• On a CORE One, chamber grille open for PLA.
• Part cooling fan working, with the shroud clear.
• Brim on large or sharp-cornered parts.
• Retraction set from the maker's numbers.
• Filament dried to its maker's setting, not hotter.
• More perimeters, not more infill, for a stronger part.
• No PLA parts in hot cars or other spots near 50–60 °C.

If you're still choosing a spool, our PLA shortlist compares the spools themselves.

How this guide was checked

This is a research-based guide. We haven't run these tests for it. Every setting, quote and recommendation comes from the Bambu Lab, Prusa Research, Prusa Polymers, Polymaker, ELEGOO, Overture and eSUN pages and data sheets listed in the sources, retrieved on 2026-10-13 (the Prusament PLA data sheet on 2026-10-14). Settings are kept to the product or printer each page names, and where makers disagree we show both. ELEGOO's settings come from the specification section of its product page. Read more in our editorial standards.

PLA: what to check before you buy a spool ↗