A Bowden extruder, an E3D clone hotend, and cooling fans

I have been working on the Bowden extruder for the Delta Pi these days. To test the extruder and the hotend before actually installing them in the Delta Pi, I decided to finish assembling my heavily customized Prusa i3 Twelvepro and to design a Prusa i3 X-carriage mount for the Bowden hotend, complete with both an E3D fan duct and a layer fan system. This is the result of my design effort.

The setup as it stood untested, a couple of days ago. The layer fan was not quite reaching the correct position and angle, so I designed some new parts.

You can see the new Z-shaped arm. The fan duct is also new, this is version V3.

Here it is positioned so that the airflow reaches very exactly the extruded material under the tip of the nozzle

Top view of the print head, ready for the first print tests. The left fan is to cool the E3D aluminum body by providing a proper airflow over the fins; it must be connected to the 12V supply and is on whenever the printer is powered. The right fan is the layer fan, controlled by the PWM D9 output on the RAMPS.

And then the long-awaited first print!

This is a calibration object from Thingiverse. As can be observed, retraction was not properly adjusted yet, but apart from that the print came out surprisingly good, all things considered.

These are the parts required for assembling the Bowden extruder (which is a simple remix of Dominik Scholz's design on Thingiverse): basically two relatively small printed parts (the extruder body and the idler), a 608ZZ bearing held in place by a M5 screw and washer, a MK8 gear, a NEMA 17 stepper with good torque (40Ncm), a push-fit Bowden connector, a small spring, and some M3 screws, nut and washers.