Taz 6 Titan Aero Upgrade: E3D Stepper Non-Responsive

Discussion in 'Titan' started by Brandon Hart, Aug 24, 2017.

  1. Brandon Hart

    Brandon Hart Member

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    Hi all!

    I have designed a custom tool head for my Lulzbot Taz 6 which allows it to use the Titan Aero extruder, including the new E3D Slimline Titan extruder (https://e3d-online.com/nema17-12-7n-cm-titan-slimline-stepper-motor-d-shaft). Everything works great...except that the stepper doesn't turn at all. It's like the printer is preventing a cold extrusion or something. I get nothing from the stepper motor at all. Am I missing something silly? Is there some sort of incompatibility with the E3D stepper and the Taz? I've gone over all of my wiring a couple of times, verified that the original steppers work fine, and even swapped out the E3D stepper with a spare one I had on hand with the exact same results. I'd love any ideas you all can throw out there. Thanks!


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  2. Spoon Unit

    Spoon Unit Well-Known Member

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    Few checks. Does it feel hot(don't get too close). If you turn the extruder cog by hand, does it move? Will the extruder move with no filament loaded? Have you wired it into the right extruder motor and selected the correct tool? When you fitted the nozzle, did you heat to 240 and then tighten the nozzle to ensure a perfect connection from nozzle to heatbreak? Is the temperature reported on whatever you use to monitor the machine?
     
  3. Brandon Hart

    Brandon Hart Member

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    Thanks Spoon Unit! I got frustrated with it last night and walked away. I won't have a chance to mess with it again until later tonight. But below are the answers I have for now until I do more testing tonight.
    Does it feel hot(don't get too close). -No, when I was messing with it there didn't seem to be any temperature change. I will double check this tonight though.
    If you turn the extruder cog by hand, does it move? - Yes, and it doesn't feel like it is bound up at all. It turns as freely as I can expect a stepper to turn.
    Will the extruder move with no filament loaded? - No, it will not.
    Have you wired it into the right extruder motor and selected the correct tool? - Yes, I am only running a single extruder on my Taz and there is only one connector for the whole tool head on the Taz so I'm certain it is plugged into the correct extruder connector. But to be sure, I pulled all the wires out and reconnected them last night. Still didn't work.
    When you fitted the nozzle, did you heat to 240 and then tighten the nozzle to ensure a perfect connection from nozzle to heatbreak? - Yes
    Is the temperature reported on whatever you use to monitor the machine? - Yes, I was just using the printer's LCD screen and the hotend temperature rose and fell exactly as it should during heating and cooldown. I was afraid that the machine wasn't seeing that the nozzle was hot and therefore preventing cold extrusion, but that doesn't seem to be the case.

    I have another pancake stepper with the same connector as the E3D stepper. I am going to swap it out and see how it works tonight, assuming I can't get one of my two E3D steppers functioning. I'm also going to remove the drive gear from the assembly and see if the E3D extruder motor will turn with absolutely zero force pushing back on it. Another idea I had was to connect the stepper connector to my BigBox Dual and see if the BigBox has any issues getting it to turn.

    Is it possible that the current requirement is so different from my standard NEMA 17 steppers that it isn't enough/too much? That seems unlikely, but I ran out of the "likely" causes last night.
     
  4. Spoon Unit

    Spoon Unit Well-Known Member

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    Recommendation is to feed steppers at between 50% and 80% of the rated voltage. Look yours up and tune the stepper driver accordingly. Definitely a possibility that it's not being fed enough. Certainly worth checking.

    When I asked about moving the cog by hand, I meant with the hot end at full temp, thus pushing the filament though manually and seeing it squirt from the nozzle. This was just to make sure the nozzle was all fitted properly and there was no obvious clog.

    Might also be worth double checking the wires to the stepper are all in the right order, at both ends. Usually, this just ends up with the stepper going in the wrong direction though, rather than not working at all, but worth checking. If the temp is reported, then it's probably safe to assume the nozzle is hot, so the manual test should rule out a nozzle clog. Then I would try some manual GCODE submission to work on the stepper. Providing you have the right tool selected (assuming T0), then G1 E10 F150 should turn the stepper, which you should observe by seeing the exposed wheel turn anti-clockwise.
     
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  5. Brandon Hart

    Brandon Hart Member

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    Ok, so I tried multiple other steppers over the weekend, all with the exact same wiring, and all of them work perfectly. It's only the E3D steppers (both of them) that don't seem to want to respond. I suspect it must have something to do with the signaling. One thing I did notice is that when I send the command to the stepper to start turning, the E3D steppers have a very short initial "twitch," after which there is nothing. This made me think that it's receiving the command, but that it isn't compatible with it. Thinking this might be due to the fact that the E3D steppers are .9 degrees/step instead of the 1.8 degrees/step that all of the others are (I checked their datasheets), I'm now looking into what firmware updates may be needed to send the commands in the appropriate increments. Any tips for where to look would be awesome. Otherwise I'll look around.
    UPDATE: I found another .9 stepper and got the same reaction as with the E3D one. So that would seem to confirm my suspicions.
     
  6. Brandon Hart

    Brandon Hart Member

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    Still no luck. I doubled my ESteps and there was no change whatsoever. Just for kicks, I attempted to cut them in half just in case I had it all backward. Same result. It doesn't seem like anyone else has had this problem (google searches come up empty). The Taz 6 uses a RAMBo board, which doesn't use pins to set microstepping. My ESteps were set to 830 previously, and it works great with any 1.8 degree steppers, but none of the 3 9 degree steppers. I'm absolutely positive that I'm just overlooking something.

    Help?
     
  7. Spoon Unit

    Spoon Unit Well-Known Member

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    Until you figure it out, can you not just fit a 1.8 degree stepper and get on with what you need to do?
    From what you're reporting, it does sound as if maybe the wires are crossed. Sorry I can't really offer anything more concrete.
     
  8. Brandon Hart

    Brandon Hart Member

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    Thanks for the response again, Spoon Unit! Sadly, no. My custom tool head was built with the specific dimensions of the E3D stepper in mind so that the nozzle position would remain the same as with the stock Taz 6, and allow for the auto bed leveling without modifications to firmware. As a result, this shorter stepper goes through the backplate and sits flush against the mounting carriage for the X-axis. The only steppers I could use would have to be equal or shorter to the height of the E3D steppers. And then I don't know that they'll have enough torque. I suppose I could put a little 1.8 degree/step pancake stepper in there for now, just to do the rest of my testing. But that's definitely not going to be my final solution.

    You state that you think the wires are crossed--are the connectors different for a .9 degree/step motor than for a 1.8? I hadn't considered this, as the connectors plug in the same way, and I haven't seen any mention of rewiring in my searches thus far. Again, the 1.8 motors work fine. It's just the .9 versions (both E3D and non-E3D) that don't.
     
  9. Spoon Unit

    Spoon Unit Well-Known Member

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    I'm no expert on the differences between the steppers. I just seems odd that you have .9 degree motors that don't work and 1.8 degree motors that do. Certainly the voltage required to move them is likely to be different, and that would be worth checking carefully. I have a feeling they will require far less. I don't suppose you have some other electronics you could quickly test the motors on in order to test them away from the printer?
     
  10. jfb

    jfb Well-Known Member

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    Odd that it seems to be *any* 0.9 degree stepper.

    If there is some possibility the wires are crossed then possibly the simplest way I've ever heard to check is here https://www.duet3d.com/forum/thread.php?id=843 - and more here http://digital.ni.com/public.nsf/allkb/0AEE7B9AD4B3E04186256ACE005D833B - basically just find the pairs. i'd also compare what you find on the 0.9s to what you find on motors you know are working on your machine.

    Other than that, the only thing I can think of is that maybe the rambo is very sensitive to firmware configuration - I've never used a rambo board (whichnI think the Taz 6 uses) so can't speak from experience. Don't know if there's anything here https://www.matterhackers.com/news/3d-printer-firmware-settings-stepper-motor-configuration that might help...

    I'd check (or recheck) the wiring and the firmware config. I'd also recheck the current.

    If I suspected faulty steppers I'd probably try to find another board to drive them for testing - or maybe just try driving it from x or y for testing purposes, but I really think that's extremely unlikely from different suppliers and only on 0.9s - way too much of a coincidence.
     
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  11. Brandon Hart

    Brandon Hart Member

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    Eureka! I found a wire that was barely hanging on. Oddly, it was the thermistor ground wire and not anything to do with the stepper. As soon as I touched it, it fell off and I got a mintemp error (nice to see that is working properly). Apparently it was a bad crimp on the connector. Not sure how/if that would affect the stepper, or why it would only affect the .9s, but I now have the 1.8 pancake working beautifully in my custom tool head. Going to do some more testing and will report back shortly. Thanks for the help!
     
  12. Brandon Hart

    Brandon Hart Member

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    Well, I'm sad to report that even with the new fixed thermistor wire, my .9 motors continue to refuse to budge. Changing the eSteps still doesn't help either. Also, I went to go actually print something with my new "Aerostruder," as I call it, and started calibrating my ESteps before I started. I was rather surprised to find that the little 1.8 pancake was extruding at about twice the intended rate. Stock Taz 6 is 830 and I turned the ESteps down to less than half of that (350) before I gave up. Also, a few times during my ESteps calibration the motor decided to turn the opposite direction for about 20-40mm and then go back the right direction again. It's nice and quiet while it's doing all of this--no buzzing or humming or anything--it just seems to go in the direction it feels like going, rather than the direction I want it to go.

    So...something odd is going on. I think tomorrow I'll try rewiring everything. The previous tool head still works great, so it doesn't seem like I have fried anything on the control board. Very strange.
     
  13. Brandon Hart

    Brandon Hart Member

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    Good news! After rewiring the connector it is now working! I went back and reexamined the wiring and still can't find anything wrong with it, but clearly it was the problem, so it's now in the trash. I got a little ahead of myself and just used the suggested ESteps value for the Titan of 837. My first print looks like garbage. Hopefully by recalibrating my ESteps I'll get better results.

    But my issue with the stepper not turning is resolved! Thank you both, Spoon Unit and jfb!
     
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  14. Spoon Unit

    Spoon Unit Well-Known Member

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    Try not to apply any pre-knowledge to the E steps. Just re-calibrate it with a well measured 100mm extrusion and plunk in the new number, however odd it looks. Let the print quality be your judge.

    Tool for calibration if it helps

    https://www.thingiverse.com/thing:1876946
     
  15. Brandon Hart

    Brandon Hart Member

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    Haha, nice Spoon Unit! I've measured my filament for ESteps calibration so many times that I have made my own "special tool" out of a PCB ruler. But thanks for passing that along.

    As a side note/follow up from the stepper motor discussion, it seems like the default current being supplied by the Taz for the stock stepper motor is about half of what the E3D Slimline Titan stepper wants. The benchys that I have printed are pretty awful looking. On the RAMBo board that the Taz uses the current is adjusted in firmware for the digipot chip. Hopefully once I make that adjustment it will start working a lot better.
     
  16. Spoon Unit

    Spoon Unit Well-Known Member

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    Looking forward to a pre- and post- change benchy image then :)
     
  17. Brandon Hart

    Brandon Hart Member

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    And you shall have it, sir. Unfortunately my machine is tied up with a customer order at the moment (using the previous tool head--also custom). So I have to be patient and wait for it to get done before I can mess with it again.
     
  18. Brandon Hart

    Brandon Hart Member

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    Sorry I haven't gotten the before and after pics posted--I haven't forgotten. Honestly, I got pulled into some other things and this project got put on hold, probably until January. Thanks for your help though!
     

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