Written by Logan F.
Status, September 2026: Superseded. Prusa Research replaced the MK4 with the MK4S in August 2024. MK4 owners can fit the official MK4 to MK4S upgrade kit.
The Original Prusa MK4 is an open-frame printer built around the Nextruder, with load cell first-layer calibration and Input Shaper. It has been replaced by the MK4S, but it remains a reliable, repairable workhorse.
Build Volume |
Max Nozzle |
Max Bed |
Extruder |
Enclosure |
Auto Levelling |
Multi-Material |
Bed Type |
About the MK4
The MK4 was a major redesign of Prusa's i3 line. The Nextruder uses a load cell to sense the bed through the nozzle, so there is no manual Z offset to set, and Input Shaper reduces ringing at higher speeds.
Prusa sold the MK4 as a kit or fully assembled, backed by detailed online manuals in the Prusa Knowledge Base. That documentation is still one of the best reasons to own a Prusa.
The 120°C bed covers a wider range of materials than many open-frame printers. ABS, ASA and PA6-CF all benefit from a hot bed, and the 290°C Nextruder reaches the temperatures most of OzFDM's engineering range needs. ABS and ASA still warp without an enclosure, and carbon fibre filaments need a hardened nozzle.
The MK4 works with the MMU3 multi-material unit, which swaps between up to five filaments in one print. PrusaSlicer, Prusa's open-source slicer, is the base Bambu Studio was built from, and OrcaSlicer in turn builds on Bambu Studio. The MK4S update brought improved print cooling, and the upgrade kit lets existing owners catch up without replacing the printer.
ProsLoad cell sensing for automatic first-layer calibration Input Shaper for high-quality prints at speed 120°C bed for engineering materials MMU3 compatible for multi-material printing Excellent documentation Official upgrade kit to the MK4S |
ConsSuperseded by the MK4S No enclosure: ABS and ASA need an external solution Carbon fibre filaments need a hardened nozzle |
Best For
- Makers who value repairability and open source
- Reliable functional part production
- Learning 3D printing mechanics in depth
- Multi-material printing with the MMU3
Print Profiles
Recommended print settings for OzFDM filaments on this printer. Click any profile for full details, notes and troubleshooting tips.
- PLA on Prusa MK4
- PETG on Prusa MK4
- ABS on Prusa MK4
- Nylon (PA12) on Prusa MK4
- PA6-CF (Carbon Fibre Nylon) on Prusa MK4
Ready to print? Grab your filament from OzFDM.
Good starting points for the MK4:
- PLA+: tough PLA for everyday functional parts
- PETG+: impact and heat resistance without an enclosure
- ABS+: heat-tolerant parts, best printed in an enclosure
- PA6-CF: stiff engineering parts with a hardened nozzle
Free shipping on orders over $299, and 5% off when you buy any 3 or more rolls of filament.
