Extruder questions

  • I have a Rostock Max V3 which I just upgraded to a dual extruder (single nozzle). I have had a weird extrusion issues that I thought went away until after I upgraded. First of all, on dual extrusions I use PVA in the second extruder and turn off retractions all together. This is because the PVA is very soft and it appears to be very easy for it to grind down and then not extrude. The T0 extruder gets clogged after a few hours when I am printing a model that needs retraction. My retraction settings are 5mm retraction, 5mm wipe and 40 mm/s speed. Someone at the SeeMeCNC forum told me that retractions above 3mm are not recommended which I think must be wrong. The Max has a long boden tube and I am amazed that 5mm works. I am wondering if this is a problem with the extruder and if there are better ones available that won't cause this problem. Of course, any easier solutions are most welcome. Advice and wisdom much appreciated.

  • There's a lot of information you didn't provide. You don't mention which extruders you do have (did you buy an additional EZR for the second extruder?) or which hot end exactly (I assume Cyclops). You also mention not using retraction for PVA then list off the retraction settings you're using, so that's confusing.

    Can you please clarify?

  • Sorry for the confusion. I am using the SeeMeCNC dual extrusion kit which includes a second EZR and am using the standard HE280 hot end. I turned off retraction for the PVA extruder and am only using it on the model filament. The settings I listed are for the model filament.

    I just started using a dust filter (from thingiverse: https://www.thingiverse.com/thing:190118) and that may have solved my problem. Not sure why, I guess the long bowden tube combined with the Y connector and 10cm tube to the HE280 may provide enough friction under some circumstances that the filament moves too slowly through the extruder causing the extruder to grind down the filament so the extruder isn't able to move the filament anymore.

    Are there better extruders that aren't so easy to jam that are compatible with my Max V3?

  • Thanks for clarifying. We're not too familiar with the dual extruder upgrade from SeeMeCNC since we don't carry that product, but your theory sounds probable. If the dust filter works, then it sounds like a working solution.

    As for other extruders, the Bondtech QR is a great extruder, and is definitely an upgrade over the EZR. A mirrored version is available so you can maintain symmetry.

    You will also need a mount, which we sell on our design store: https://www.matterhackers.com/store/digital-designs/bondtech-qr-extruder-mount-for-rostock-max

  • Thanks. I will need 2 mounts, I'm hoping they won't get in each others way. I am enclosing a picture of the dual extruder setup. Please let me know if your mount will fit. If not, can you give me some specs for mounting the Bondtech? I'll be able to design a mount that way. Again, thanks -- Ivan

  • The mount I linked to is designed to be mounted to the ceiling, like the extruder on the V2 was. If you want something more similar to your existing setup, this Thingiverse design might be what you're looking for: https://www.thingiverse.com/thing:2136630

  • Thanks very much! I need to modify the model with the single extruder mount to hold 2 of them. Shouldn't be too difficult.

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