What firmware settings should I change first?

Start with steps/mm for all axes (most critical for dimensional accuracy). Then set conservative speed and acceleration limits, and tune upward. Finally, adjust jerk or junction deviation for print quality vs speed trade-off.

What is junction deviation?

Junction deviation is Klipper and Marlin 2.x alternative to the older jerk setting. It controls how much the printer slows down at corners. Lower values = slower cornering (better quality), higher values = faster cornering (faster prints). Typical range: 0.01-0.08mm.

How do I convert Marlin jerk to junction deviation?

Junction deviation = Jerk² / (2 x Acceleration). For example, jerk 10 with accel 3000 gives JD = 100/6000 = 0.0167mm. This is an approximation but gives a good starting point.

What happens if steps/mm is wrong?

Incorrect steps/mm causes all prints to be the wrong size. If too high, prints come out larger than designed. If too low, prints are smaller. Calibrate by printing a known-dimension test object and measuring with calipers.

What is the maximum step rate for common boards?

ATmega2560 (RAMPS): ~40kHz. STM32F103 (SKR Mini): ~100kHz. STM32F407 (SKR 2): ~200kHz. RP2040 (SKR Pico): ~200kHz. Higher step rates allow faster printing with high microstep counts.

3DPrintCalcs

Firmware Settings Calculator — Steps/mm, Feed Rate & Acceleration

Calculate key firmware values like steps/mm, max feed rate and acceleration.

Motor Steps/Rev

Microstepping

Belt Pitch

Pulley Teeth

Max Speed

Max Acceleration

Jerk

How We Calculate This

Firmware Calculation Formulas

Steps/mm = (Motor steps x Microstepping) / (Belt pitch x Pulley teeth)
Max step rate = Steps/mm x Max speed
Max feed rate = MCU max step rate / Steps/mm
Junction deviation = Jerk² / (2 x Acceleration)

The maximum print speed is ultimately limited by the controller board's step rate. Higher microstepping increases steps/mm but reduces maximum speed. TMC drivers with interpolation help by accepting lower step rates and interpolating internally.

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify settings with test prints before committing to final prints.