Why First-Layer Adhesion Matters for PLA and rPETG FDM Prints
Getting first-layer adhesion right is essential for PLA and rPETG FDM print success. The nozzle must be calibrated to the correct distance from the bed, and the surface must be prepared properly. Without both, prints lift, warp, or detach entirely.
Nozzle Distance and Calibration
The goal of first-layer calibration is to adjust the nozzle height until the extruded plastic sticks nicely to the bed and is being slightly squished.1 Printers assembled at the factory are already fine-tuned, and recalibration is only needed in specific cases.1
Getting this distance wrong can cause adhesion failure. The calibration process must account for differences in plate type, since different surfaces have different Z offsets that affect how close the nozzle sits to the bed.2
Plate Type Selection for PLA and rPETG
Choosing the wrong plate type in your slicer is a common adhesion problem. If you slice a model for the Cool Plate and print it on the Textured PEI Plate, there is a high chance the model will not adhere to the plate as expected.2 This happens because each plate has different properties and temperature requirements.
The Cool Plate requires around 35°C for PLA, while the Textured PEI Plate requires around 55–65°C for PLA.2 The Textured PEI Plate also has a different Z offset, which impacts how close the nozzle is to the print surface for the first layer.2 Selecting the correct plate type according to the filament used gives the best chances of success.2
Surface Cleanliness
A dirty bed is a cause of adhesion failure. Strongly recommended practice is to wash the plate before starting a print.2 Contamination from handling or leftover residue undermines the bond between filament and surface.
Adhesion problems are described as prints not sticking to the build plate or material warping during printing.3 Keeping the surface clean is a direct countermeasure to both failure modes. Selecting the correct plate type while also ensuring the plate is clean gives the best chances of success.2
What to Watch Next
For PLA and rPETG FDM prints, the three levers to check first are: correct plate type selected in your slicer, nozzle distance calibrated to produce a slight squish, and a clean print surface.12
See more: More guides