MMU2/3 assembly guide on Prusabox

Parts overview

Step 1 Disassemble MMU2/3 brackets

Unscrew the 4 x m3 screws to remove the original bracket

Unscrew 2 x m3 screws to disassemble the electronic mmu board cover.

Disconnect the pulley motor (yellow) and the selector motor (red) and add one or two cable extender.

Depending on your MMU version, motor cable won’t have the same length. Cable extender is not always required for both motors.

Step 2 Doors

Insert M3 nuts into each slots of handles

Remove plastic protection from both sides of each plexiglas doors

Position handles on top of the translucent doors. Make sure they are oriented like the picture

Screw handles from under, with 4 M3*6 screws

Step 3 Printed parts assembly

Insert M3 nuts into each slots

Assemble the middle cover with the two frames, use 4 M3*10 screws

Assemble the front cover with the two frames, use 2 M3*10 screws

Step 4 Slider assembly

Screw half-way a M3*12 screw as in the picture

Insert both parts of the sliders inside the frames

You can close the sliders and the front cover. The slider will follow MMU’s movements, while keeping the enclosure closed. It should move freely. Depending on the print quality, you might have to trim the long edges.

Step 5 Install MMU2/3 on frame

Install MMU2/3 unit on the frame

Screw using screws that you remove on step 1

Add the back cover with 2 M3*6 screws

Step 6 Electronic board assembly

The cover for the electronic board is the same as the original. But we designed a file that can be printed in two colors using MMU

Insert M3 nuts into each slots

Assemble both parts using M3*18 screws. Make sure you wire the cables as in the picture.

Depending on your version of MMU, you may need to add one or two of the motor cable extenders.

Step 7 Assembly on PrusaBox

Install the 3 blocks as shown in the picture, using M3*6 screws

Install the electronic board with a M3*6 screw, but don’t tighten too much as the left door will go between the printed part and the metal frame

Install the MMU unit on the PrusaBox. Use M3*6 screws at the back

Insert PTFE tubes you got with your MMU, and install the doors

Insert PTFE tube between the extruder end the MMU, that should go through the hole in between the two parts of the slider

The PTFE should be long enough for the extruder to reach the X axis left and right extremities when it is in the lower Z axis position.

Step 8 Secure motor cable

Use zip tie to secure motor cable on the back over of the mmu2/3 frame part, and to secure the cables along the printer frame through it’s way to the main board.