Axis Steps/mm
Steps per millimeter for X, Y, and Z axes — determines positional accuracy of the print head and bed.
Low priority
Printer-Specific
What It Is
Axis steps/mm defines how many stepper motor steps move each axis exactly 1mm. Set by belt pitch, pulley teeth, and motor step angle. Rarely needs adjustment on properly built printers.
What It Controls
- Dimensional accuracy (X/Y/Z dimensions of printed parts)
- Layer height precision (Z-axis)
- Hole and slot sizing
Why It Drifts
- Almost never drifts on belt-driven axes (determined by hardware geometry)
- Leadscrew-driven Z can drift with wear or backlash
- Only changes if hardware is swapped (different pulleys, belts, leadscrews)
How to Calibrate (Manual)
- Print a known-dimension cube (e.g., 20×20×20mm)
- Measure with calipers
- Calculate:
new_steps = current_steps × (target_mm / measured_mm) - Apply with
M92 X<val> Y<val> Z<val>, save withM500
Note: If dimensions are off, check flow rate and temperature first — over-extrusion causes dimensional errors too.
How the Auto-Tuner Calibrates It
- Dial indicator or laser displacement sensor measures actual travel vs. commanded
- Low priority — rarely needs correction on modern printers
Related Anomalies
- Elephant Foot — can appear as dimensional error (but usually caused by compression, not steps)