ECAS04 magnetic bowden coupler

I created this model (in openscad) from scratch to allow for self-aligning, simple, quick-release bowden tube connectors.  It takes three 6x3mm magnets and an ECAS04 collet on each side; the position of the magnets aligns the tubes together and filament passes through easily.

I used no-name 6x3mm magnets and ECAS04 connectors, both available in bulk from Amazon.  My “6x3” magnets actually measure more like 6x2.6mm, but there's enough clearance in the parts that true 6x3s should work as well.

The magnets are designed to be tight enough that they shouldn't need glue; I made 12 pairs of these and not one of the 72 magnets has shown any sign of coming loose.

The printed parts in the STL are designed with 1.2mm wall widths to be printable out of the box with either a 0.4 or 0.6 nozzle.  I printed using a 0.6 nozzle with 0.2mm layer height in ABS and they came out great.

I've also provided the openscad file (with tweakable parameters for all the sides) so that you can tweak tolerances and shapes to your heart's content.

Assembly

Assembly is simple enough: push in the ECAS collets, and push in the magnets.  The only thing to keep in mind when putting magnets in to mind the polarity: all three should be the same way on one part, and all three should be opposite polarity on the part you want to join it to.

One way to do this is to use a stack of 6x3mm magnets: push from one end into the three magnet holes on the first part, then push from the opposite end of the stack into the other part to make a mating part.

Alternative models

While looking for a connector I came across a couple alternatives: one using M6 threaded connectors (https://www.printables.com/model/90814-magnetic-bowden-coupler) and another using E3D collets (https://www.printables.com/model/373184-magnetic-ptfe-bowden-coupler).  Both looked good, but I didn't have enough threaded M6 connectors, nor any E3D collets, thus this version.  I took some inspiration from the triangular shape of the latter model, though this is a from-scratch design.