Bambulab AMS printed funnel for V2 with PTFE coupler (ECAS)

Given that my feeder reached their end-of-life, I was thinking of potential replacements. With 10€ per feeder and an estimated lifetime of around 1.5 years, I do not want to keep buying feeders.

The model this remix is based on is already very close to the original feeders, but there were some adjustments I had to make. I have one of the newer AMS models (note the orange gears instead of the yellow ones), and that one uses a tiny spring with a magnet to sense whether filament is inserted. The original model had the spring exposed, which I didn't want (I fear loosing it).

While going through the many prototypes, I became sick of always having to drill out the holes, so they were adjusted to not need that.

How to print?

It is important to print it in the correct orientation. I made the tolerances with these orientations in mind. It might be necessary to calibrate the filament to get it to print right. This is how the parts should be printed:

If you are planning to use the ECAS fittings, please don't use a lot of infill/walls. The more it has, the harder it will be to remove the fitting, if you have to reprint it.

The hole, where the spring goes in, might need some manual cleanup. Make sure the spring fits snugly, otherwise it will be harder to assemble the feeder into the unit.

How to assemble?

You can assemble the feeder like described in the model this remix is based on. If you are planning to use the ECAS04 version, remove the rubber piece from the fitting, and then press it into the printed part with a good amount of force. Important: Removing it is impossible without destroying the printed parts.

You shouldn't have to drill out any of the holes if you printed it in the correct orientation (hopefully). By the way, I used superglue (the one that hardens in a few seconds or minutes) for my feeders (instead of resin), works just fine.

What to be careful of?

I strongly recommend, to test pushing filament through the feeder before you completely assemble the AMS. Also note where it gets stuck. I had a problem where I couldn't push the filament through, it later turned out that it wasn't the top where the spring pushes the bearing onto the drive gear, but the magnet where the filament sensor is.

Make sure that the magnet with the spring for the sensor sits at the right height. You can compare to the original feeders or refer to these images:

(yes, my picture of the printed one is kinda bad)

The spring depth is important, because otherwise the printer will always think that filament is inserted, or you will have a very hard time pushing filament past the magnet.

Sometimes when the filament can't be inserted, it helps to move the feeder a bit to the left or right.

The Bambulab Instructions say that you should push an allen key through the hole to remove this metal shaft:

Based on experience, I can tell you that you won't be able to remove the metal shaft that way. It is stuck in there so well that I couldn't remove it without pliers. I recommend bending the transparent outer housing until you can free the funnel from the other side.

Be careful when tightening the screws of the feeder unit assembly. If you over-tighten them, the plastic might snap. (I am speaking from experience here).

The connector on the circuit board on the funnel is glued. This is to reduce the risk of you ripping the connector off the board or accidentally becoming loose. You can do the swap without removing the glue. If you have to remove it, drench it in IPA for some time and very carefully cut the glue away.

How well does this work?

I have replaced all four feeders, 3 of them are working like the original ones, and one requires a bit of fiddling/force to insert the filament into. My guess is that the part where the spring sits hasn't printed that well, and now the spring pushes on it too strongly.

I tried multiple long prints involving a decent amount of filament swaps, and had no issues with it. Mine were printed in regular PLA with regular wall/infill settings, I don't know how long they will work.

Do I recommend doing this?

It really depends on how much time you have, how patient you are, and what your budget is. The AMS Feeder Unit is not designed for maintenance. Removing the funnel is painfully fiddly, and takes a good amount of time.

For all 4 feeders, the process of cleaning the gears, housing and replacing the funnels took me at least two days. (I estimate it would take around 2 hours of work per unit). I disassembled them so many times that I am sick of it.