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Solved Print quality when scaling up model

Discussion in 'Troubleshooting' started by astro boy, Jan 9, 2018.

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  1. astro boy

    astro boy Member

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    Ok well I have had simplify support and after supplying them with my fff file, they said it should print normally and offered that it might possibly be a bad contact or wires at the servo, to which I have tried to make it fail by wiggling the wires to the extruder while manually using the jog controls to extrude. I know this is not a completely foolproof way of determining a good connection but I have not been able to make it repeat the same behavior. I pulled the servo motor and gear that turns the extruder gear and found no mechanical issues there. I have no doubt it is something I did wrong. I have a feeling I corrupted some part of a program while trying to hook up my raspberry pi 3. I never completed the install cause I was having connectivity issues between the pi and robo. Could I have corrupted the firmware in the robo possibly trying to program the pi? Or changed something important in simplify? I'm really at a loss. My next step is to change my bed offset in cura so I can confirm that the extruder servo only behaves erratically when using simplify 3D. It seemed to print normally when using cura, the only problem being that it was printing way off center and I had to abort.
    Ps been sick for a few days and am just getting back to this.
    Thanks
     
    #21 astro boy, Jan 16, 2018
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You could want to reset the EEPROM in the printer. From a GCode terminal do this:

    M502;

    and then an

    M500;

    That will reset the EEPROM back to what the firmware defaults are.
     
    #22 mark tomlinson, Jan 16, 2018
  3. astro boy

    astro boy Member

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    Thanks Mark
    That's exactly what I was looking to do last night but couldn't figure out how.
    I'll try it when I get in tonight and see if that solves it. I'll keep you posted.
     
    #23 astro boy, Jan 16, 2018
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  4. astro boy

    astro boy Member

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    Well I tried resetting the firmware and it acknowledged that it did but there is no change. It seems to be getting worse. Now I'm questioning if it's a servo issue. I unmounted the extruder servo and gear and observed the behavior while it was unattached and printing. The shaft rotates in the same manner. It seems to go back and forth (extruding/retracting) for a quarter of the circumference of the model, extrudes, then back to hobbling back and forth almost every quarter. It is pretty consistent. Assembled it all back together and same result. I can manually extrude through the simplify machine control and it's smooth as silk. But I can't print anything. I tried using cura last night and I'm not sure it's working properly in that program anymore. Just a couple weeks ago I made some beautiful prints. I'm almost at a loss. I don't think anyone's experienced this before. I'm going to keep on experimenting, tried to print something last night that I know prints well and it was just a stringy mess. I have a video but it might not upload because it's a big file. I'll try
     
    #24 astro boy, Jan 17, 2018
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If it is spinning both directions that sounds like retraction settings (from the slicer side) but it could also be something flaky with the drivers I suppose. When you just straight-up tell it it manually extrude there is no retraction, the slicer generates that when you are slicing for a print. Try disabling retraction entirely in the slicer(s) and see if it changes the behavior in a small test print.
     
    #25 mark tomlinson, Jan 17, 2018
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If disabling the retraction has no effect then it is almost certainly a hardware issue (although, a strange one that I have not seen before...)
     
    #26 mark tomlinson, Jan 17, 2018
  7. astro boy

    astro boy Member

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    Mark,
    That was my next question. Could it have something to do with the extruder stepper driver? It seems like the situation is getting worse over time although I can't be certain of it. I'm going to try disabling retraction which I guess would be done by UN-checking the retraction Box in the extruder tab graying out all the settings?
     
    #27 astro boy, Jan 17, 2018
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Depends on the slicer the exact steps, but that sounds about right.
    Yes, it is possible that the stepper driver (or the RAMPS, but that is less likely) could be misbehaving it is even remotely possible (at a real stretch) that the Arduino could be misbehaving. First rule out software entirely and then we can start stepping through the hardware. I would certainly start with a stepper driver at the hardware side... even with no spares you could swap the one for the extruder with another axis (X/Y/Z) and see if the behavior changed
     
    #28 mark tomlinson, Jan 17, 2018
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  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I will say that normally when a stepper driver goes bad they just get 'weak' and stop providing enough current to drive the motor and you start missing steps. However it is electronics so anything is possible on a failure mode these days. Electronics are not as simple as they used to be :)
     
    #29 mark tomlinson, Jan 17, 2018
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  10. astro boy

    astro boy Member

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    ok here are the latest developments. I tried swapping stepper drivers and the extruder servo is behaving the same way. I think I've mentioned the situation seemed to be getting progressively worse with the behavior. I decided to take the motor of the hotend to see if it would behave the same without any load on it. To my surprise, it exhibited the same behavior even using manual jog controls. Now at one point I was suspecting the harness. I would turn the motor upwards stretching the harness and it would smooth out, and change position it would behave erratically. It did this a few times while i played with the harness but now it doesn't go smooth at all and just behaves erratically all the time. I'm not sure if it's the motor or the harness. at this point since the harness position doesn't change anything, I suspect the motor. ....any thoughts? Get both? What stepper would I buy in any case... model wise?

    thanks

    ps I thought for sure it was a software/firmware issue since I was screwing around with the raspberry pi. Which I ended up abandoning. I hope it is just a motor or cable.
     
    #30 astro boy, Jan 18, 2018
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Any NEMA-17 stepper that is the same (or close) physical dimensions is 200 steps/rev (they may call this a step angle of 1.8 degrees, same thing) and has decent torque (somewhere around at least 40 nm) will work without any changes.

    I used these: https://www.amazon.com/gp/product/B00QEXSCE8 simply because I wanted spares for all the printers. You can find single steppers if you look.
     
    #31 mark tomlinson, Jan 19, 2018
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  12. Geof

    Geof Volunteer Moderator
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    are you certain the stepper cable is plugged in all the way? I've seen some wierd stuff happen. You may want to unplug and test the wires then reseat the cable and test before you buy a stepper

    (side note: I'm a huge fan of on hand spare parts )
     
    #32 Geof, Jan 19, 2018
  13. astro boy

    astro boy Member

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    Yes I wanted to mention something else as far as cable contact with the stepper. I removed the motor and plugged unplugged several times with the same result. Although, after taking the motor off, I realized my wiring harness and some of the plastic parts of the hot end have a lot of canola oil on them. I thought I had been using it sparingly, only a few dropper drops into the oil feed that I printed per print. But it has built up around the hot end. Could the contacts not be making good contact because of this? I did try and wiggle the connector while plugging it into the motor with no difference in behavior.
    Is there a better way to do the oil feed so it isn't all over? One dropper full instead of three? I will probably get the stepper motors just to have on hand. I would think the oil on the contacts wouldn't make much difference, but maybe your experiences have been different?
    Thanks all
     
    #33 astro boy, Jan 19, 2018
  14. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I add a few drops of oil to my oilers... once a blue moon.
    In all seriousness it is not often. It will depend on usage, but more than once every couple of weeks is probably overkill.
    A little bit goes a long way. The oil is only re-seasoning and the seasoning will not wear out that quickly.
     
    #34 mark tomlinson, Jan 19, 2018
  15. astro boy

    astro boy Member

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    Thanks Mark,
    I was definitely going overboard with the oil then. I ordered the motors on Amazon, should be in Sunday. Hopefully by Monday this thread will be solved! Thanks for all the help guys... Battle is not won yet! But I think it's close.
     
    #35 astro boy, Jan 19, 2018
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  16. astro boy

    astro boy Member

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    Ok well got my stepper motors, now the shaft on my original has two flat sides a v cut I would say while my new ones have have a d cut (one flat side) I suppose I file the shaft to make the gear fit, is this how you have done it Mark? Or anyone who has replaced an extruder stepper? Kind of a bummer I couldn't get the exact one.
     
    #36 astro boy, Jan 21, 2018
  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Does yours not have the set screw in the side like this? If not you can add it. I guess Robo could have used press fit for the gear. It is not the best way to do it, but it is a low-stress joint so it could work.

    630px-NCLewis_Wade_Gears.jpg

    When I print a GregsWade I always use this style. It is just easier. You can try a press fit if your will fit in there snug enough and then print this style of replacement gear (takes like 15 min) to use.
     
    #37 mark tomlinson, Jan 22, 2018
  18. astro boy

    astro boy Member

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    Unfortunately my Small servo gear doesn't have the set screw config. It is a v with a half moon that matches the shaft that keeps it in place.
    I'm going to try and create the shape on the motor shaft to match my plastic gear. I have a grinder at work that'll do that quick enough. I'll just protect the motor from the shavings.
    Since I have spares, if it's not satisfactory, I could always print the gear after assembly. I'll let you know how it goes. Going to try and reassemble everything tonight and give it a go.
    Thanks again
     
    #38 astro boy, Jan 22, 2018
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  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Whatever approach you are comfortable with.
    I have used press fit and set screws and even a combination of the two :) It is not a gear that has a lot of torque on it so any approach will work. Do yourself a solid and once you get printing, print an entire GregsWade assembly. Eventually you may want to print all the plastic bits on the printer. If you ever get a second printer it is less critical since you can just print what breaks on-demand.
     
    #39 mark tomlinson, Jan 22, 2018
  20. astro boy

    astro boy Member

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    Yes Mark,
    Great suggestion. I will definitely do that when I get running again. I was tempted to buy a second machine when they had the New Years sale. I ground down the shaft already. I brought the old shaft with me to work to compare, unfortunately I didn't bring the fear to see if the fit is good to make any final adjustments, duh! Lol
    It looks pretty good though, hopefully it will only need slight filing if any.
    Thanks again!
     
    #40 astro boy, Jan 22, 2018
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