Multi-material filament feeder/repurpose E1 stepper driver

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    @jckray said in Multi-material filament feeder/repurpose E1 stepper driver:

    @dc42 This worked great. I have another question related to my filament feeder.

    I am using a limit switch as a filament presence detector. Is it possible to set up a command to extrude until the switch is triggered?

    The only type of "endstop" officially supported for extruders is stall detection, allowing you to extrude until motor stall. However, there may be a way to achieve what you want. Create another dummy axis, without any real motors (e.g. specify driver 11) and use the filament switch as the endstop for that axis. If the new axis is U, use a command such as G1 S1 U1000 E1000 Fxxx. Caution: I haven't tested this.

  • @jckray, nice to see that you drive your design with a Duet 🙂

  • Looks really interesting, i will keep an eye on this, I like the idea of a completely duet compatible solution.

  • @jckray Looked at your project on Thingiverse and left a comment, but figured I might as well reach out here as well; definately interested in building one of these for myself.

    Once you get firmware working I would be happy to test it as well and give some feedback. If you have a semi-complete BOM I'm sure I could find most of the stuff I would need lying around in the engineering dept. building at my university.

  • @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

  • 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?

  • @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.

  • Ok, thanks.

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

  • @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.

  • @red-sand-robot A supper rough BOM is now on our Thingiverse page along with updated files

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

  • @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.

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

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

  • @fma the cutter is using a standard Xacto knife blade. Here are some pics2_1539711414812_IMG_0226.JPG 1_1539711414812_IMG_0225.JPG 0_1539711414809_IMG_0224.JPG

  • 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...

  • @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.

  • 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?

  • @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.

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


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