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Dual Direct Extruders?

Discussion in 'Mods and Upgrades' started by gstercken, Jul 26, 2014.

  1. gstercken

    gstercken Member

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    After roughly 2 months of using the R1, I realize how useful a dual extruder would be - especially for printing support material, and for combining rigid and flexible material in a single print. Now, I'm aware of Mike's dual bowden extruder mod, but at the same time, I'm reluctant to go "full bowden" - especially since I need to print a lot of flexible material like NinjaFlex, Flex EcoPLA or Flex-PolyEster... And while these are already tricky to print with a direct extruder (I only managed to print them at all after upgrading to the E3D V6 hotend), from what I've read, they're near to impossible to print with a bowden extruder.

    Therefore... I'm pretty happy with my direct Wade's extruder, and would like to keep it that way. At the same time, I realize that adding a second Wade's extruder side-by-side to the RoBo3d R1's carriage would significantly reduce the x-travel, leading to a much smaller build size in the x direction.

    But how about placing two direct extruders in front of each other (along the y axis)? Or a mixed setup, with the standard direct extruder, and an additional bowden extruder?

    I haven't been able to find anything online regarding a dual extruder setup for the RoBo (aside from Mike's dual bowden), so I wonder if anyone else has already ventured into this direction? Any thoughts, ideas or suggestions?
     
  2. Mike Kelly

    Mike Kelly Volunteer

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    You could probably design a carriage that uses two EZStruders lined up along the Y
     
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  4. John Rygg

    John Rygg Active Member

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    My thoughts exactly . Would love to move to the dual extruder world but keep the direct drive benefits .
    I like the hybrid approach , that would save some weight and add the ability to print support material.

    My buddy has a Bowden setup and has all kinds of problems with material that is more flexable
     
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  5. Mikethinks

    Mikethinks Active Member

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    That would be interesting, how well does the ezstruder feed system work? Since its feeding directly off the motor without any gearing my concerns are that you wont get accurate feed and that the motor will have less torque for resistance in the melt zone.
     
  6. tesseract

    tesseract Moderator
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    the main problem I see is the added weight having to throw around two nema motors with each move will probably significantly slow you speed down
     
  7. Mike Kelly

    Mike Kelly Volunteer

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    It's a direct drive extruder. Accuracy is less of a concern I'd say and is capable of higher speeds. Though you are correct in that it would have less available torque. Typically on a direct feed you don't need that much torque, Leon has been running a direct feed ezstruders for months now without issue. Only with Bowden have I seen you really need a lot of torque
     
  8. gstercken

    gstercken Member

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    Thanks a lot for your input, everyone. So, in short... If I want dual extrusion (with at least one direct extruder) I basically have to design my own solution, since nobody has ever done that before on the RoBo? That's all I wanted to know.
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Pretty much.
     
  10. gstercken

    gstercken Member

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    Would it really? Is this a proven problem, or just a theoretical guess? I wonder how much the added weight of an additional full Wade's extruder, including the NEMA motor and all, would actually have a significant impact on the agility of the carriage. Is the total weight/mass of the overall print head setup really a mesurable factor when it comes to printing speed?

    More generally speaking: Is the mass of the print head that needs to be moved around generally an issue in 3D printer design? Is there something like a design goal to make print heads as light as possible?
     
    #10 gstercken, Aug 7, 2014
    Last edited by a moderator: Aug 7, 2014
  11. Mike Kelly

    Mike Kelly Volunteer

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    Carriage weight is THE factor in determining printing speed.

    The RoBo is mostly limited by the glass bed, which has quite a bit of inertia you need to slow down.

    Inertia is the enemy for 3d printers. The more you have, the more vibrations, and the less consistency.
     
  12. gstercken

    gstercken Member

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    Very interesting... And surprising for me. Sheds an entire new light on the different 3D printer designs out there, including delta, cartesian, and whatnot. For me, the R1 works just perfectly. I never had any issues that seem to stem from the general design of the printer.

    It also makes me thankful for the RoBo3D R1 working as flawlessly as it does. In spite of all the shortcomings (manufacturing quirks, heated bed issues, delays, missing feedback from customer support, you name it) I still get very good results - my prints come out just great, and I appreciate it. I'm really a glowing fan of the R1, as much as I suffer from those small manufacturing issues, and the bad customer support and communication.

    Darn, the R1 could be such a great printer! If only they wouldn't ruin it with those few little manufacturing flaws, and then not responding to customer requests in a timely and satisfying manner.
     
  13. Mike Kelly

    Mike Kelly Volunteer

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    Yeah I agree. I'm almost to the point where I can start recommending it to people.

    They received 500 printers from china this week and was anticipating 100 would go out by friday. Once the back orders are fulfilled they should have at least one more person to help on technical support and they have 1-2 people working customer support.

    If all goes to plan the communication and documentation should improve rapidly. Until that happens I have a hard time recommending this, over say a printrbot simple metal.

    The reason delta's are capable of such high speeds is because they're usually bowden fed which makes for a very lightweight carriage.
     
  14. gstercken

    gstercken Member

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    Oh, wow... And there, I had always perceived you as a RoBo3D "fanboy", who would promote and excuse anything and everything they do, just because you're a moderator here, and have close connections to the RoBo team.

    That's good to know. From my impression, the printers straight out of the Chinese manufacturing plant suffered from serious manufacturing flaws (cable lengths, wiring, messy heated beds, faulty power switches...) I really hope they managed to correct those issues at the root, without having to fix and reconfigure everything again in San Diego.

    Yep, that would be great. Again, I'm amazed that you (in my image, so far, the eternal RoBo3D fanboy) would even consider mentioning another printer like the printrbot. ;-)

    But, seriously... I have also considered ordering another printer (Solidoodle 4g) with a working heated bed, over the frustration of not getting any feedback about the heated bed fix from Jerry. But I'm over that, by now... I'll just fix the bed myself, it's really not much of an issue, once you have gone through the hassle of upgrading the hotend to an E3DV6.

    I just love my R1 too much... It's really a great printer.
     
    #14 gstercken, Aug 7, 2014
    Last edited by a moderator: Aug 7, 2014
  15. Mike Kelly

    Mike Kelly Volunteer

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    Yeah I'm kinda a paradox. I love the robo for the freedoms of modding it enables me. As you can see that's pretty much more fun for me than actually printing.

    In terms of build volume and cost it's kinda hard to beat. The solidoodle 3 is a good competitor though and it's kinda hard to justify the higher robo3d cost. That said I'm a big proponent of open source models, so I usually don't suggest it.

    The Printrbot simple metal really wins my affection by being all metal. That and the proximity sensor is a nice touch. It certainly has it's limits as it's PLA only and hard to modify. I usually recommend it because it's a great value for the price, but only if you don't care about modding or multiple materials.

    Besides that I usually push the UM2. I love the looks of that machine but the price is kinda prohibitive.

    Just kinda hard to tell people to buy a product when there isn't even an up to date getting started video...
     
  16. tonycstech

    tonycstech Active Member

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    Check out this monster

    Pretty weird but cool.
     
  17. polylac

    polylac New Member

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    This is a monster! but it's nice that you can print over the whole build platfomr (though the thing is that wide that one loses maybe a lot XD)
     

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