The plan is to use the delta robot as a 3D printer (like makerbot,reprap, ect). To keep the inertia of the head low I’ve decided on using a Bowden extruder. The Bowden extruder works on almost the same principle as a bikes brake cable, the plastic filament to be melted is driven through a tube to the hot end where it is melted. This reduces the weight of the printing head as it moves the filament driving stepper motor away from the heated head.
The following shows a design I’ve been working on for the cold-end, which drives the plastic filament down the Bowden tube to the hot-end. The design is based around a Nema17 stepper motor, it also uses 626 bearings (because I have a bunch spare), a handful of 6mm bolts, and two springs (for tensioning purposes).
Not shown in the above image are the springs used to tension the idler bearing carriage against the driven spindle.
The following shows a cut-away view exposing the driven spindle and idler bearing.