Multi-material filament feeder/repurpose E1 stepper driver

jckray

@red-sand-robot We are currently reworking it to include a filament cutting mechanism as we have been experiencing issues with loading due to a bad tip on the filament about 2-5% of the time. More info will be coming to the Thingiverse page fairly soon, we are very busy so it is hard to always keep everything up to date. We do not have a specific BOM for the filament loader as is is combined into the BOM for the printer we are developing. We can probably get a rough BOM for the loader at some point when we have time. The only challenging part is the stepper motor with the really long shaft. We had to have this custom made.

If you are interested in what we are doing, there is also information on our website https://www.hydraresearch3d.com/nautilus/

fma

I get very nice tip on PLA by removing filament with this macro:

G1 E-5 F3600
G1 E2 F3600
G1 E-47 F3600
G4 P5000
G1 E-100 F3600

I'm about to test my own version of filament multiplexer, but I'm a bit lost with the configs. Would you mind sharing yours?

jckray

@fma We have a fairly similar unload script, however, we are still having issues with consistency across all material types, specifically breakaway supports from E3D. I'm hoping to have updates on our progress including the config and scripts we are using some time next week. You can check our website and our Thingiverse page for updates, links below.

https://www.hydraresearch3d.com/nautilus/
https://www.thingiverse.com/thing:2992637

fma

Ok, thanks.

Where does the jam occur? Between the loader and the carriage?

jckray

@fma In occurs when loading the filament back in when right as the filament enters the nozzle. Some filaments, the breakaway in particular, have a slight bulge at the tip after unloading.

jckray

@red-sand-robot A supper rough BOM is now on our Thingiverse page along with updated files https://www.thingiverse.com/thing:2992637

gavatron3000

did the knife improve reliability? ive seen the prusa mmu2 struggle with the E3d breakaway also in videos

jckray

@gavatron3000 I have not tested the e3d breakaway since adding the cutting mechanism. I have had it up and running with the blade for a day and a half now. So far reliability is much better. I will let you know how the breakaway supports go once I have tested them.

fma

Where did you put the cutter? On the loader carriage, as Prusa did?

jckray

@fma Yes, it's on the carriage. I'll see if I can get some pictures.

jckray

@fma the cutter is using a standard Xacto knife blade. Here are some pics

fma

I'm thinking to add a cutter under the extruder. This way, cut tips stay in the hotend, and are pushed again by the new filament during the purge, so no need to evacuate them. Ideally, it would be nice to be able to cut the filament when it is still soften, above the melt chamber, but I don't think ti would be easy...

jckray

@fma No, that does not sound easy. We had to use the method we did because our tool head is pretty complex and already has a magnetic hotend cartridge system, so something like that would not fit on our tool head and would make that portion of the printer too complicated.

fma

BTW, I made some quick tests cutting filament with hot wire (easy to build, with a NiCr wire + led current driver). I didn't not spend much time: it cut very well, but leaves some small borders on the tip of the filament. I need to dig further this method.

BTW, I'm wondering if having the nozzle drilled at 1.7mm instead of 2mm could help to avoid bad tips?

jckray

@fma That sounds interesting, would love to hear more if you ever to any more testing.

Yes, I have had the same thought about the diameter of the nozzle, however, this would mean you would only be able to use expensive filament with a very good manufacturing tolerance.

fma

Well, I said 1.7mm, but yes, 1.8mm would be better. But not 2mm...

Red Sand Robot

@jckray

Excited to see the progress on it! I for one would be interested in hardware kit, though I might try to see if it would be possible for me to fabricate some of the non printed pieces in my university's metal shop.

Is everything running well on the firmware side of things?

jckray

The firmware is running fine. We are still ironing out a few minor issues.

jckray

@red-sand-robot Glad to hear you would be interested in a kit. We will need to see interest from more people before we would make an official kit. However, if we don't do a kit we can definitely help you out with the hard to find/custom parts if you need them.

Red Sand Robot

@jckray How much, roughly, did the NEMA 17 with the custom shaft? I have already begun printing the parts for your MMU system, so far so good!

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