Prusa Printing Tutorial

This is a tutorial on using Prusa 3D printers for multi-material printing. The information here is based on a training attended by Tomáš and Luis.

0. What the heck?

• To turn on the printer, use the black 0/1 switch on the side.
• To use the menu, use the orange button (called knob) on the front: press to select, move (counter)clockwise to go up/down in the menu.

1. Setting up a printer (for 1^st use / after moving)

1. Clean the printing bed (floor) with isopropyl alcohol or a window cleaner.
2. Clean the nozzle, i.e., remove any dried filament from the nozzle.
3. Calibrate: turn on the printer, go to menu, select Calibrate Z (calibrating X/Y is not necessary).
4. Preheat the printer: go to menu, select Preheat, select PLA (or whichever filament type you want to un/load, the filament type should be written on the side of the coil!).
5. Wait until the correct temperatures are met!
6. If there is already a filament inserted and you want to remove it: go to menu, select Unload filament ## (numbered from left to right), remove the filament.
7. Load new filaments one by one: use pliers to create an arrow-like tip on the end of the filament, then go to menu, select Load filament ##, slowly push the filament into the input (should be located on the bottom of the black&orange boxes on the top of the printer) and wait until the motor loads the filament.

2. Printing a file

When the printer is set up according to the previous steps, we can proceed to print a file.

1. Make sure the printing bed is clean and all necessary filaments are loaded, if not, you can follow some of the steps from the previous section.
2. The file to be printed has to be copied on an SD card (included in the printer).
3. Go to the menu of the printer, select Print from SD, select the file. There are already a few files preincluded on the card, there should be a time necessary to print them included in the file names.
4. Always verify the quality of the first printed layer: while printing, go to menu, select Live Adjust Z, and adjust the Z height in runtime so that the first layer is smooth as shown in the picture. Once you are satisfied, leave the printer finish printing the rest of the object. In case the first layer is too bad, press the orange X button to cancel and reset the printer. Then repeat the printing from the beginning.

3. Using the Slicer

First of all, download and install Drivers & Apps for MK2/S Multi Material.

Note: There are two different slicers available: the one we are going to use is called Slic3r Prusa Edition (installed together with the firmware), but there also exists a much simplified version called PrusaControl. In the future, both slicers would eventually get combined into a single application.

Slicers are used to generate a G-code (i.e., instructions for 3D printers, CNC machines, etc.) from imported .stl files. It is the slicer's responsibility to create a printable code from a model. There are various settings available, most of them already correctly preset by Prusa.

For general instructions, please refer to: https://help.prusa3d.com/l/en/article/AdioGxcy3t-slic-3-r-pe-prusa-edition

Using slicer with multi-material objects

Generally, objects consisting of more materials (e.g., more than one color) must be saved in multiple .stl files, each one corresponding to a single material. These files have to use the same coordinate system so that the different parts are positioned correctly to form a single object.

When importing a multi-material object into Slic3r PE, select all the .stl files of the object and drag&drop them together into the slicer window. When doing it this way, the slicer will ask you whether all files form a single multi-material object. Select that yes, they do form a single object. This way, the slicer will generate a correct G-code for multi-material printing.

In order to edit the colors of the different .stl parts, double click the object in the right pane.

Important! If you imported the .stl files separately, the slicer would possibly not generate a correct G-code.

Important! When importing multiple .stl files together as a multi-material object, the new Slic3r PE automatically handles self-intersections in the order of import (i.e., usually in alphabetical order of the file names). Example: Let 1_head.stl be a complete object of a human head (including both eyes) and 2_righteye.stl is just a right eye of the face. When imported together to Slic3r PE, we can choose 1_head.stl to be printed one color and 2_righteye.stl another color and we would get the right eye printed in a different color, even though 1_head.stl already includes the right eye.

What does it mean? In theory (to be verified in practice), we can keep the original .stl (main color) intact and only export the parts in different colors into a second (third, fourth) .stl file. The Slic3r PE would automatically detect the self-intersections between 1.stl and 2.stl and would apply the different colors "on top" of the original object.