First Layer Calibration: Z-Offset, Baby Steps, and Squish

Why the First Layer Is Everything The first layer is the foundation of every print. Get it right and the rest follows naturally. Get it wrong and you'll fight adhesion failures, warping, and detachment for the entire print. A perfectly calibrated first layer is slightly squished into the bed — not floating above it, not so squished it won't peel off. The goal: a layer that sticks during the print and releases cleanly after. -- Understanding Z-Offset Z-offset (also called Live Adjust Z, Baby Steps, or Z-calibration depending on your machine/slicer) is the small vertical correction between where your machine thinks Z=0 is and where it actually needs to be for perfect first layer squish. Too high: the filament doesn't bond to the bed — lines are round on top, gaps between lines visible, print pops off easily. Too low: the nozzle drags through the filament — lines are flat and merged, no gap visible between lines, possible nozzle scratching the bed surface, elephant foot (base of print is wider than intended). Just right: lines are slightly flattened, edges just touching each other, surface looks smooth, you can see individual lines but they're bonded together. -- The Paper Test (Manual Leveling Baseline) Before any auto-leveling or software adjustment: 1. Home the machine (all axes) 2. Disable steppers: send M84 or use your printer's interface 3. Manually move the nozzle to each bed corner 4. Slide a standard sheet of paper under the nozzle 5. Adjust the bed corner screw until the paper slides with slight friction (you feel resistance but it moves) 6. Repeat for all four corners + center 7. Repeat the whole process 2-3 times (adjusting one corner affects the others) This is your mechanical baseline. Everything else is software fine-tuning. -- Live Z Adjust During First Layer This is the best way to calibrate — watch the first layer happen and adjust in real-time. In OrcaSlicer: 1. Print → Live Z Adjust (or baby steps via the printer panel) 2. While the first layer is printing, use the +/- buttons to move Z 3. Move by 0.02-0.05mm at a time 4. The change takes effect on the next line the nozzle prints 5. Save the offset when first layer looks correct In PrusaSlicer with Prusa printers: 1. The first layer calibration is built into setup — follow on-screen prompts 2. Live Adjust Z: rotate the knob during first layer print 3. Accept when squish looks right In Cura with custom machines: 1. Set Z-offset in Cura's Machine Settings or as a start G-code value 2. Use an OctoPrint plugin (Bed Level Visualizer, BabyStep) for live adjustment 3. Alternatively: adjust via the printer's LCD if available -- The Squish Test Print Print a simple 0.2mm-tall, 50×50mm square (a single first layer): 1. Look from above: lines should be slightly touching, surface should look smooth and continuous 2. Look from the side: thickness should be close to 0.2mm — not higher (air gap) or much thinner (too squished) 3. Try to peel it: should require slight effort but come off cleanly. If it welds to the bed, you're too low. 4. Feel it: should be flat on the bottom (bed side) with slight ribbing on top -- Elephant Foot Correction Elephant foot is when the first layer (or few layers) is wider than the rest of the print. The part looks like it's sitting on a tiny skirt it grew itself. Cause: Z too low, first layer squishes out sideways; or first layer speed too slow for the temperature. Fix in slicer: Elephant Foot Compensation setting (OrcaSlicer, PrusaSlicer). Start at 0.1mm and increase until the base matches the rest of the print. Alternative fix: raise Z offset by 0.02-0.05mm until elephant foot disappears without losing adhesion. -- First Layer Settings Checklist -- Auto-Leveling vs Manual Auto-leveling (BLTouch, CR Touch, Klicky, PINDA): probes the bed at multiple points and builds a mesh. Compensates for bed tilt and warping automatically. Limitations of auto-leveling: it measures from the probe tip, not the nozzle. If probe offset is wrong, your Z-offset will be wrong. You still need to calibrate Z-offset even with auto-leveling. Mesh bed leveling (Klipper, Marlin 2.x): creates a fine grid of bed height measurements and applies real-time Z correction as the print head travels. The most effective solution for warped beds.

Related Guides

Loading_