Bed Adhesion: Surfaces, Cleaning, and Parts Popping Loose

Which plate surface gives which adhesion?

Textured PEI, smooth PEI, glass, and flexible magnetic plates do not behave the same way. According to Bambu Lab's documentation, a textured PEI plate is made by spraying a layer of PEI powder onto a spring-steel sheet, producing a textured surface on both sides and a matte finish on the bottom of the printed part; it generally gives good adhesion across many materials without needing extra adhesive. A smooth PEI plate is made by bonding a PEI sheet to spring steel with a heat-resistant adhesive, giving a flat surface prized for a smooth, consistent part bottom.

Glass gives a very flat, smooth surface, often paired with hairspray or glue stick for adhesion on PLA, but it needs more chemical help than PEI does. Flexible, magnetic plates that detach from the machine do not change the coating itself, but they make removal easier once the part has cooled, cutting the risk of forcing a thin part off and breaking it.

Cleaning the plate: soapy water, IPA, or detergent?

The Prusa Knowledge Base recommends 90% isopropyl alcohol as the best option for routine care of smooth, satin, and textured plates. When adhesion degrades over time despite regular IPA cleaning, it recommends switching to warm soapy water, with a few drops of dish soap, to dissolve oils and sugary residue that alcohol alone does not fully remove.

Bambu Lab's PEI plate cleaning documentation takes a slightly different angle for textured surfaces: alcohol tends to spread grease around rather than lift it off that kind of texture, and a detergent applied with a sponge or a soft brush cleans the texture's grooves more effectively. Both sources agree on one point, though: never use acetone or ketone-based solvents on a PEI plate, textured or satin, since they can damage the coating; Prusa reserves acetone for occasional use, roughly once a month, and only on a smooth PEI plate.

Either way, avoid touching the print area with bare hands right before starting a print: finger grease is one of the most common causes of lost adhesion on a plate that is otherwise in good shape.

Glue stick, hairspray: helpful or counterproductive?

According to Prusa, a PVA glue stick is not needed to print PLA on a PEI surface in good condition, and can actually hurt adhesion by forming an uneven film. It becomes useful for PETG, ABS, ASA, nylon, and flexible materials instead, where it creates a thin separation layer that protects the PEI surface and wipes off easily with soapy water.

Hairspray or spray adhesive, more common on glass plates, work on the same principle but build up faster in uneven layers if not removed regularly, which can hurt adhesion after several prints instead of helping. The rule of thumb is simple: reach for an adhesive for a technical material or a smooth surface like glass, not as a default habit on a textured plate that is already clean.

Step-by-step method for diagnosing an adhesion problem

Start by noting where the problem shows up. If the defect is limited to one corner or one side of the plate while the rest sticks fine, the likely cause is a leveling gap rather than a pure adhesion issue, so check the bed leveling page first. If the defect is uniform across the whole surface, move to the next step.

Clean the plate using the method suited to its surface: 90% IPA for routine care, soapy water if adhesion has degraded over time, detergent and a sponge on a textured plate. Run a test print without changing anything else, to isolate the effect of cleaning.

If the problem persists, check the bed temperature recommended for the material in the slicer profile, then raise it in 5-10 °C steps if the material is known to be hard to stick. Only if none of these steps work should you reach for a material-specific adhesive, as a last resort rather than a first move.

Brim, skirt, and raft: adding a margin from the slicer side

When part geometry is the real issue, a small footprint, overhangs, or a part that is tall relative to how much of it touches the plate, plate settings alone do not always fix it. A brim, that thin border printed around the base of the part, increases contact area without changing the final geometry once peeled off. A raft adds a sacrificial platform under the whole part, useful on a very uneven base or a material prone to warping.

Both settings live in the slicer and work alongside surface and cleaning settings rather than replacing them: a generous brim on a dirty or poorly leveled plate rarely fixes the underlying problem.

Special cases: difficult materials

PETG sometimes bonds too well to hot textured PEI, to the point of pulling material off the plate on removal; letting the part and plate cool to room temperature before removing it, rather than forcing it off hot, cuts that risk. Nylon and fiber-filled materials often need a dedicated adhesive, since PEI alone is not enough according to Bambu Lab's documentation. TPU, being softer, usually sticks easily but deforms more if you force removal too early.

For all of these materials, the manufacturer's data sheet remains the reference for bed temperature and recommended surface, ahead of any trial-and-error adjustment. Engineering filaments like polycarbonate or fiber-filled blends often need an enclosure to keep ambient temperature stable, on top of a hot bed, since a draft cooling one side of a tall part faster than the other can pull it off the plate long before the print finishes.

When the plate itself is not the problem

Adhesion troubleshooting sometimes runs in circles because the real cause sits upstream of the plate. A nozzle that is partially clogged under-extrudes the first layer, leaving too little material in contact with the surface for any cleaning routine or adhesive to fix. A print speed that is too fast for the first few layers has the same effect, since the nozzle does not spend enough time pressing each line onto the plate before moving on.

Before reaching for a different surface or a stronger adhesive, it is worth confirming that the first layer itself extrudes cleanly and at a sensible speed on a plate already known to be clean, level, and at the right temperature.

Sources and limits

• Prusa Knowledge Base — First Layer Issues
• Bambu Lab Wiki — PEI Plate Clean Guide
• Bambu Lab Wiki — Build Plate Types

We organize manufacturer and community documentation; we have not measured these products ourselves. The manual for your exact model takes precedence over general guidance.