Ultimaker mounts up to 4 extruder 'cassettes'

Why we wanted it
A stock Ultimaker comes with a single extrusion head fixed to the X and Y axes. As we were experimenting with dual extrusion printing, modifying this design became increasingly inconvenient and time-consuming.

To make developing the hardware-side of our multihead printing much easier, we decided to split the extruder head design into two indendent hardware parts. The 'frame' part is fixed to the X and Y axes and thus determines the head's location. To this frame, up to 4 '