Introduction: Creating a 3d Print Enclosure for Prusa MK2/3 or MMU

About: A beginners guide to raspberry pi and Arduino development by beginners.

What is this article and why did I write it?

I was fortunate enough that on the facebook Prusa thread that Jochen Heyd created a wonderful article on how to make a custom Lack enclosure. that article is awesome reading if you have never done this before and gives several different options for electronics. I wanted to build an enclosure that is future proofed for addons, new printers, etc, so this is more of a guide of various things to consider and tips. I also included information for both printers.

Step 1: Dimensions - Don't Use the Spec Off the Website!

General Notes

Please note the sizes below are not the ones for the enclosures above. These are minimum dimensions for the printer.

  • Remember that you need room for cables on the side for Y motor to not catch on anything.
    • Similarly a cable sticks out the back off heatbed
  • Some people mount their filaments above enclosure, and that's fine.
    • I'll include both sets of measurements
  • These measurements are slightly padded. Not by more than an inch or two.
  • MMU has rack behind it. I included general sizes
  • Because I do not know the thickness of materials you are utilizing, treat these as internal measurements for your box

MK2/MK2S (and I imagine MK3 will be similar)

  • Internal box Height (assuming filament is outside): 14"
  • Internal box Height (assuming filament is inside): 26"
  • Width: 23" (accounts for power cord sticking out of PSU and black cable run on opposite side)
  • Depth: 21" (including back cable run and lcd)


  • Internal box Height (accounting for tube height)
  • Width: 23" (accounts for power cord sticking out of PSU and black cable run on opposite side)
  • Depth: 21" (including back cable run and lcd)
  • Height: 18" including boden tubes

MMU - Tray

Suggested MMU/MK2/TRAY Setup

  • W: 32"
  • D: 26"
  • H: 18"

Step 2: Octoprint and PI Camera

I would offer the following configuration for consideration:

  • Raspberry Pi3 with Official Touchscreen
  • Graph the octoprint image from
  • Burn it to SD card
    • Network configuration via the textfile never worked for me, I always went into linux to fix it
  • Pi 2 camera or webcam (Pi2 is safer for compatibility if you'd not comfortable configuring things in linux
  • TOUCHUI for octoprint if you are using a Pi touchscreen.
    • I also configured Pi to boot to browser
  • Setup Pi to autostart to browser if you use a touchscreen!

    • To exit out of octoprint using the touchscreen, use the ctrl N to open a new tab
      • Then use menu to exit. It brings you back to terminal!
  • (Optional)Enclosure Plugin + Temperature Sensor
    • This provides clear instructions for the use of a temperature sensor
      • I ordered a DS18B20 and bought the breakoutboard version from Sparkfun. It installs on PIN4
      • This is great because you can monitor the temperature remotely and also slave the fan to it if you have a relay. See next item!
  • (OPTIONAL SLAVED LIGHT) Buy a 5v relay and the enclosure plugin allows you to add buttons. I added a light slaved to it so I could turn on a light remotely when using webcam at night. This same type of relay could allow the pi to control fan via the Enclosure plugin too!

Camera Position

  • The best views I would suggest are
    • (BEHIND/BESIDE) 45 degrees horizontally (so not head on)
      • Either on the side of the PSU or behind so the nozzle is clearly visible
      • Just above heat bed so you can see your first layer clearly
      • The downside is once the model is tall enough you can't see the rest of the tray
      • But for small models and first layer this is ideal
    • (FRONT-Downwards view)
      • Slightly off to the side and 45degrees downward, about a foot away from the printer.
        • This allows you to see the whole tray and see lifts/pieces moving, but it's harder to see first layer and you cannot see nozzle. This is a real problem on small models.

Step 3: Electronics

In Jochen’s article he mentions three approaches:
1) A temperature sensor-board
2) inkbird
3) pi with relay to fan, enclosure plugin

Havings done all three approaches I feel strongly that the Pi configuration I mentioned ia best approach. Less wires, more configurable. But I do suggest putting the PI on the outside. Similarly put the lcd for the printer on the outside if you think you will be doing ABS.

You can find my electronic high level walkthroughs on my channel for both approaches


Pi and temp sensor

Step 4: Additional Resources

Mmu - serving filament from above