Workshop: Introduction to 3D printing with the Prusa I3 MK3S 3D Printer

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(Generally, this workshop is offered at least once every week on a rotating basis. Check the DaBL calendar for up-to-date availability!)

The Prusa I3 MK3S is a 3-axis CNC printer - an additive manufacturing machine. Fabricating with this machine is relatively simple. The CAM software used to convert your CAD model into a set of instructions this machine will understand is called Cura.

The Process

3D printing consists of only three steps:

  1. Preparation
  2. Print
  3. Clean up


  1. Set up the machine
  2. Set up the material
  3. CAM the object

Set up the machine

  1. Turn on the machine. The power switch is located on the back of the righthand side box. The screen should turn on.
  2. Spot check on the machine. Make sure that:
    1. the bed is clean.
    2. the extruder nozzle isn't covered in hardened filament.

Set up the material

You may need to unload filament before you load in new filament!

To unload filament, in the interface:

  1. Click the knob to open the main menu.
  2. Scroll down and select "Unload filament".
  3. Scroll down and select "PLA".
  4. Wait for the extruder heater to get up to temperature.
  5. Once the extruder heater is up to temperature, follow the screen prompts to pull out the filament.
  6. Remove the filament spool from the spool holder, and then:
    1. clip off the melted end so that it is clean and there are no burrs.
    2. roll the excess filament onto the spool.
    3. place the spool in its box.
    4. place the box on the filament stock shelves.
  7. Clean up any excess filament.

To load filament, in the interface:

  1. Click the knob to open the main menu.
  2. If the temperature is already up to target, you may skip to step 4. Otherwise, Scroll down and select "Preheat".
  3. Scroll down and select "PLA".
  4. While you wait for the extruder heater to get up to temperature:
    1. select a filament spool and remove it from the box.
    2. if the end isn't clean, clip it off so that it is clean and there are no burrs.
    3. place the spool on the spool holder with the end spiraling off toward the front of the machine..
  5. Once the extruder heater is up to temperature, click the knob to navigate back to the main menu.
  6. Scroll down and select "Autoload filament".
  7. With the end of the filament in your hand:
    1. slide it through the filament guide on the top of the machine
    2. carefully slide the end into the filament feed on the top of the extruder assembly.
  8. Follow the screen prompts to ensure the filament is loaded properly.
  9. Your material is set up!

CAM the object

  1. Pull the SD card from the lefthand side of the 3D printer screen enclosure and insert it into the SD card reader USB stick connected to the front face of the computer.
  2. Badge in to the computer.
  3. Start Cura (last icon (light blue) on taskbar).
  4. Open your stl model. It should appear in the build area.
  5. In the top left of the interface:
    1. In the machine selection, make sure the Prusa I3 MK3S is selected.
    2. In the material selection, make sure "Hatchbox PLA" is selected.
  6. Set the parameters how you want them. For a simple print, the Basic interface allows for only the four most important features of the print:
    1. Layer height: how thick should each layer be? This affects the quality: thinner layers give you finer resolution, and an overall nicer-looking print. However, it will also significantly increase the print time, which may render the job impractically long.
      1. Typical setting: 0.2mm
    2. Infill percentage: how dense should the inside of the object be filled? Less infill results in a weaker object, but significantly reduces print time. If you're testing dimensions, less infill is better.
      1. Typical setting: 20%
    3. Support: how does the CAM package treat overhangs? If there are overhangs in your model, adding support will allow them to be printed without significant error. Adding support does increase port-processing time, as you'll need to remove it once the print is done. Some objects will fail 100% of the time if supports are not added.
      1. Typical setting: yes, everywhere
    4. Adhesion: how does the object stick to the bed? Adding adhesion types will help increase the chances of edge-case objects printing successfully. They will also, however, require more post-processing, as you'll need to remove it once the print is done.
      1. Typical setting: brim
  7. In the bottom right of the interface, press the large button labelled "Save to Removable Disk".
  8. Once it has saved, click "Eject Removable Desk" in the bottom middle
    You're ready to go!


  1. Remove the SD card from Prusa screen
  2. Carefully insert SD card back into the 3D printer and allow the machine to process.
  3. Scroll to your generated G--code file and press the knob.
  4. The machine will begin its job!
  5. Stick around for at least the first 5 layers, as if a print fails, it will likely fail during this time.

Clean up

Always leave the machine cleaner than what you found it! Before you walk away from the machine, make sure to:

  1. Clean up any clipped filament and stray support material not already on the bed.
  2. For the bed:
    1. Remove any remaining support, adhesion, or clearing filament still on the bed.
    2. If a gluestick was used, wash the bed with warm water and handsoap only to remove it. Do not use anything on the bed other than soap, water, and paper towels.

This will ensure the machine is clean for the next person to work with!

Check list

Learning objects

  • Understand how to use cura
    • know how to change the layer height
    • know how to change the infill density
    • know how to change the support
    • know how to add build plate adhesion and which is most necessary for a given print
    • understand how to manipulate a design by moving throughout the build plate
    • understand how to orientate a print
    • know how to make gcode specifically for the prusa

Tangible objectives

  • know how to remove and place filament onto the prusa
  • know how to initiate a print
  • know what to do once a print has finished