Prusa i3 mk3 Printing Guide

Last modified by Darren Cocco on 2026/01/13 11:36

Safety Notes

Keep your hands away from the bed and nozzle - they are hot!

It is better to stop the print via the printer’s control menus rather than cutting the power because printers need a controlled cooldown with their fans running to prevent molten plastic migrating too high up into the extruder. If you have cut power, you can always just power it back on to resume controlled cooling

Motors are generally not strong enough to cause significant damage or injury if jams occur, and can even be pushed aside to clear a jam if necessary.

Printing

Setup

If the screen on the front is dark, the printer is probably off. The on/off button is at the back on the right.

Navigation

The knob on the front of the machine is used for navigating the printer settings. Turn the knob to toggle through menu items. Press the knob to submit the menu item, and to back out there is often a "Main" item that will take you back.

Loading filament

Unload old filament first using this section of the guide.
Navigate to the Load filament option
Select your material type from the list. It will then heat to the temperature associated with that material.
When it prompts you, load the filament into the nozzle and press the knob.
Some of the old colour may be remaining in the system so continually press the knob until it extrudes with the correct colour.

Insert SD card

The SD card goes into the hole to the left of the screen, as pictured.

Printing

Once your SD card is in the printer, select the Print from SD option, and navigate through the SD card file system to your file.
The bed will heat to the target temperature. This is done so that the first layer of extruded material is able to stick to it more easily.
After heating the bed, it will perform a bed levelling procedure. This may leave small marks on the print bed that should be removed so they don't get in the way of the print.
After the bed levelling procedure, it will start to print. It's worth standing by and watching the first layer or two of the print, because if something is going to go wrong in the print it is most likely to go wrong in the first couple of layers.