Dual X Carriage recommendations



  • Hi All. I am considering building a new Cartesian printer with dual x carriage, would appreciate any recommendations on design, also presuming Duet has no problem catering for this!

    Thanks in advance


  • administrators


  • administrators

    If you are looking for general recommendations on how to design a IDEX printer then the most well known and sucessfull design is the BCN3D Sigma. I have a BigBox converted to IDEX which is also good.

    The key things to consider are:

    • The weight of the two X axis on the Y axis (your Y axis needs to be stiff enough and well supported.

    • Having enough X travel on both X and U axis to be able to park the X /U print head off the bed completely to each side. The Sigma does this well by having a rectangular bed that is longer in Y than is its wide in X.

    RepRapFirmware supports IDEX well.



  • @dc42:

    Support for multiple X carriages is desribed at https://duet3d.com/wiki/Configuring_multiple_independent_X-carriages_on_a_Cartesian_printer#Homing_files.

    In this case, how can the wiring be done? Any suggestions and ideas.

    How two independent X can be driven?

    Thanks



  • I've now looked at the Sigma and the idea seems interesting. I was thinking though that for my traditional Cartesian with dual Z then there must be a way of constructing a Z carriage with dual heads and dual X motors that could convert to an Idex. The dual Z should take care of any weight issues. before I go and design my own is there any additional advice or do you know of any designs I can adapt?


  • administrators

    The original Idex was a "traditional cartesian" if by that you mean one that moves the bed in Y and the X axis up and down on Z leadscrews (the Mendel, the Prusa Mendel, the Prusa i3 designs):
    https://www.thingiverse.com/thing:115885

    The additional weight will be in the additional stepper motor for the U axis and associated components and U carriage, Along with the additional hotend (and extruder if not using a bowden system), this is all manageble in this type of desing, at worst you may have to slow down your Z axis acceleration a little.



  • CalviNx, thanks for the warning, I did find their website a little self adoring. I plan on doing my own build self sourcing parts though.

    Tony, thanks for the info, I already run dual Z acme screws with anti-backlash and dual direct drive heads. I'll strap a couple of spare motors on the Z carriage and run some test prints. to see if the additional weight affects print quality.



  • I had pretty god experience with BCN3D customer support. We bought the previous sigma (not the r17) and didn't actually think it lived up to our expectations, so we returned it. BCN3D obliged happily, paying for all the return shipping and everything.



  • Hi All, am progressing with my own Idex design, next stop is end stops (hah).

    Since it seems to me end stop accuracy becomes hyper critical with an Idex design to ensure accurate alignment of the nozzles, does anyone have a recomendation? Are mech stops good enough or should it be hall effect or optical, if so which ones will work best on the Duet?

    Or maybe I have missed something and my assumption is wrong.


  • administrators

    Mechanical endstop switches can give good reproducibility. For compatibility of various types of endstop switch with the Duet, see https://duet3d.com/wiki/Connecting_endstop_switches.



  • I'm nearing the end of a long ongoing dual-idex build – yes, that's correct 4 independent extruders -- 2 Y gantries with 2 extruders on each. Kinematics are working so far, I'm using mechanical limit switches -- as in all cases they're extremely accurate as long as you hit them squarely and allow the metal spring on the limit switch to decompress on your homing routine. I have yet to calibrate, so I don't know how accurate everything will be. Obviously getting each extruder on the same z plane will be the trickiest part. My design allows for some vertical adjustment, but just eye balling them -- they're really close if not dead on already. As you can imagine -- a ton of wires. I am at the actual stage of connecting everything to the duet with all wires having been neatly sleeved and constrained in cable chains. Will work on the bed soon, and see how close the nozzles are IRL.


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    @kazolar:

    I'm nearing the end of a long ongoing dual-idex build – yes, that's correct 4 independent extruders -- 2 Y gantries with 2 extruders on each.

    Sounds good! Can you confirm that the Y axis mapping facility in the M563 command that I implemented in recent 1.19 betas is working for you?

    By my calculations you have 1 driver left over. So you could implement bed levelling in one dimension using 2 Z motors if you want to.

    Getting all the nozzles at the same Z height is only important if you want to do ditto printing (printing up to 4 copies of the same object simultaneously in your case). But you probably knew that already.



  • I haven't tried your Y mapping – I will tonight, I was digging through the release notes of 1.19 and couldn't find that Y mapping was included, if it is, AWESOME!!!
    So technically I was a driver short -- recall you helped me add the 11th driver.
    Math adds up -- 4 extruders, 4 X axis steppers -- 4 Y axis steppers -- but in series, so only 2 drivers -- 2 Z axis steppers, but in series -- so 1 -- that's 11 total drivers -- so far I have connected all the motion related stuff, I will definitely try out the 1.19 beta when I get home as I'd like to be using official Y-mapping code, not my hack job 🙂
    Technically don't have to have all 4 be co-planar, I can add z-offsets, but it is easier if they're -- I plan on adding bed leveling, I have your IR differential, and I'll be trying out the piezo sensor board -- not sure which will produce best results as the IR differential would take space on tool 0, and I didn't have luck with on my delta, but that was with PEI on glass over black paper.
    Let me know when you have W/A homing sorted out, those are my secondary X axis mappings -- I can flash and test that when I get home -- essentially U is tool 1 X axis, V is secondary Y axis and W/A are tool 3 and 4 X axis -- tool 3 homes min and tool 4 homes max -- basically if you visualize a dual idex, it's just that -- except big, 40x40 aluminum frame, bed powered by 2 nema 23s at 2.8A in series -- no trouble lifting a 60KG dumbbell. Dual Y steppers on each Y gantry -- it is over-engineered.

    Yakov


  • administrators

    This is an amazing sounding machine! I would love to see some video 😄



  • @T3P3Tony:

    This is an amazing sounding machine! I would love to see some video 😄

    I've been building for almost 2 months, all of it I've been recording on video. So you will. I am extremely singly focused, so the amount of time I spend on the build – is all the "me" time I have outside of my morning 10k runs, which are less frequent with my kids getting me sick rather often. So between 2 small kids and work, my wife has been fantastic with giving me the freedom to spend as much time as I do on this hobby. Having said that, this is the first project which I decided to record, and I will edit and post it to start my YouTube channel. It was a test to see how I could work if filming would slow me down to where I'd give up the filming. So far, filming and setup of the shot -- as best as I can at this point, which I'm still far from good at, has been OK. I am looking at a stopping point where I will edit the footage -- is when it actually prints -- which I think is about a week away. At that point I will stop, take a break, and edit the almost 300GB of video I have recorded. I'll post info here and on social media -- as I'm active on the FB 3d printing groups when it will go live, I think it will be 2 episodes per week release schedule -- so I can start adding a bit of a QA into each episode as people watch. I expect it to be a number 20-30 minute highly sped up build vlogs with a bit of an intro and outro by me. And a number of folks on FB have asked me to leave in any issues I ran into, and I will, as there have been plenty, so I'm not sanitizing it as if I got everything right the first time -- far from it.

    Y



  • @dc42:

    @kazolar:

    I'm nearing the end of a long ongoing dual-idex build – yes, that's correct 4 independent extruders -- 2 Y gantries with 2 extruders on each.

    Sounds good! Can you confirm that the Y axis mapping facility in the M563 command that I implemented in recent 1.19 betas is working for you?

    By my calculations you have 1 driver left over. So you could implement bed levelling in one dimension using 2 Z motors if you want to.

    Getting all the nozzles at the same Z height is only important if you want to do ditto printing (printing up to 4 copies of the same object simultaneously in your case). But you probably knew that already.

    1.19 Y mapping working perfectly



  • PS I flashed the latest Web UI, A now shows and I flashed the latest PanelDue Firmware and now homev does indeed homev, but A is not present in the PanelDue


  • administrators

    PanelDue does not support axes beyond W. I don't think there is room on the display to support any more. Maybe we could just squeeze in A if we didn't display the Z probe reading.


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