Nail the first layer and most print problems disappear
The first layer makes or breaks a print. Get it right and the part adheres firmly and builds cleanly; get it wrong and you'll fight warping, poor adhesion or elephant's foot for the whole job. First-layer calibration is mostly about three things working together: a level bed, the correct Z-offset, and sensible first-layer settings.
Leveling means making the nozzle the same distance from the bed across the whole plate. On a manual machine, heat the bed and nozzle to printing temperature first (metal expands), then adjust each corner using the paper-drag method: slide a sheet of paper under the nozzle and turn the knob until you feel light, even resistance. Repeat the corners twice, because adjusting one affects the others. If your printer has an auto-leveling probe, run its mesh routine — but still set the Z-offset by hand.
Z-offset sets how close the nozzle sits to the bed for that crucial first layer. Too high and the lines stay round and won't stick; too low and the nozzle scrapes, causing ridges or a clog. Print a single-layer test patch and watch it: you want flat, slightly squished lines that fuse into a smooth sheet with no gaps between them and no translucent over-squish. Adjust live (baby-stepping) in 0.02–0.05 mm increments until it looks right, then save the value.
Help the first layer along in your slicer. Print it slowly — around 15–25 mm/s — so the plastic has time to bond. Use a slightly thicker first-layer height (e.g. 0.2–0.3 mm) to hide minor bed imperfections, and set a generous first-layer line width (105–120%) for extra contact. Turn the part-cooling fan off for layer one so it sticks before cooling. A first-layer bed temperature a few degrees above the rest of the print also improves grip.
Even a perfect Z-offset fails on a greasy bed. Wipe with isopropyl alcohol before printing, and remember that swapping build plates (glass vs. textured PEI) changes the effective offset, so re-check it after any change.
Once you've found the Z-offset, first-layer height and bed temperature that give you a flawless base, write them down so every future print starts from a known-good setup instead of a fresh round of leveling.
Record your calibration in PrintLog →