Berd Air Selector

Let's start with a video breakdown.

As we move into a world where toolchanging printers become the norm, we'll likely run into snags as the cost of the machine increases linearly with the number of tools. What if we could reimagine the problem tool costs as an opportunity to design shared infrastructure?

The Berd-Air Selector is my first take on a compact, cheap solution for air cooling. This stepper-driven rotating selector allows us to reroute the aquarium pump's air flow to one-of 8 different tools. Since only one 3D printer head is active at any given time, this solution cuts the cost of air cooling expenses down for every redundant extruder.

Ok, so why not use cooling fans? Fans are the norm for part cooling, but fans are rather large, taking up a sizable fraction of the total size of the extruder. The Berd-Air pump shines as a compact alternative. As opposed to a fan that sits on the extruder itself, the air source is placed elsewhere remotely, and a small hose routes the airflow from source to the hotend.

Unfortunatlely, aquarium pumps are expensive when compared to mini pc fans, but that's where my selector comes in. This selector cuts out the cost where we'd otherwise need to add redundant pumps for our second, third, fourth, ... extruder heads.

The state of the art so far:

This is currently a work in progress, so I have yet to finish writing the software for this feature. Hardware-wise, however, it is pretty much feature complete. (My only add-on at this point would be a homing switch.)

Bill of Materials

can be found here

Design Notes

• All moving surfaces that break-and-reconnect the airflow path are connected via rubber seals. This design features two seals: a laser-cut rubber gasket made from santoprene and a small rubber o-ring.

Assembly Notes:

• The delrin slip face must be lubricated with white lithium grease such that it slides smoothly