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Solved Another problem with Circles.

Discussion in 'Troubleshooting' started by SteveDjarrell, Oct 11, 2016.

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  1. SteveDjarrell

    SteveDjarrell Active Member

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    Ok guys, I have searched / found and read a couple of threads on issues with printing circles. I am having a very similar issue to those. IF I print a cylinder with a 3mm wall. The Inner circle is moved diagonal on the x/y axis. so essentially the inner hole is offset. Very weird as everything was working fine a few days ago. I have checked the y belt. I checked the y drive pulley and motor mounts. Everything is tight. For the X I check both drive pulley and belt, they are also both tight. Also everything moves freely by hand and all connections are properly seated.
    I did have an x-carriage on it last week that was a little tight and I did notice the x axis stepper motor was very hot to the touch. I have since changed back to the stock carriage and the stepper is normal temp now while running. I did re-flash the firmware to make sure nothing had changed as I had made a change last week for the z axis steps.

    Printing a cube I get a similar issue with one side being slightly wider. So a 20x20 cube is coming out 19.97mm x 19.76mm (ABS, 235C Bed 100C 50mm/sec) not nearly as bad as the cylinder but not normal.

    I am at work right now but will try to get pictures up this evening. I have checked all the mechanical and software.. Curious if physical hardware could have been damaged by the x carriage being to tight and adding resistance to the stepper motor or Driver? I am at a loss and was going to try swapping out the Stepper and the driver this evening.

    -Steve
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The stepper driver would be a good place to start since you ruled out the drive mechanical bits.
    Having the belt too tight would cause the stepper (and driver) to work harder and might cause a failure long-term.

    Those types of problems are either mechanical, electrical or software :)
    Start ruling out the culprits.
     
  3. SteveDjarrell

    SteveDjarrell Active Member

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    [​IMG]

    Well it took me a little while but here is a picture. I have replaced the x axis motor, driver and wiring. I might still need to increase the voltage a little but no I am also noticing a slight shift on the z axis toward the home side. That and the hole is still oblong. I am running out of ideas.

    Sent from my SM-G935V using Tapatalk
     
  4. JoshYourITGuy

    JoshYourITGuy Active Member

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    Confirm your steps/mm did not get changed. If you have an LCD screen, you can accidentally change them if you get "click happy"
    Do not use the "calibration cube technique" to adjust, keep them at 80/80 (or 100/100 if you are using 20T vs 16T gears)

    Swap the X and Y drivers

    Try slowing the print down quite a bit to see if it happens again, if it stops happening at slow speed, look into a mechanical issue, maybe a worn belt. If it still happens, check your slicer to make sure you dont have any Horizontal Compensation things enabled. (Simplify3D, Process, Other, Dimensional Adjustments, Horizontal Size Compensation)
     
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  5. JoshYourITGuy

    JoshYourITGuy Active Member

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    If you are worried about tension, you can always keep it a bit loose and add a bent clothespin spring dead center on the belt to keep even tension on it. I have done that and it seems to have gotten rid of the tiny bit of slop I was getting in mine.
     
  6. SteveDjarrell

    SteveDjarrell Active Member

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    Well I thought I might have had it licked, but I was wrong. So I adjusted my X stepper driver and increased it a little. Makes a much nicer sound and actually seems like it moves smoother. I then printed at 30mm/sec and I got a fairly round circle. Can barely see that it is off, but it is. I sped it back up to 60mm/sec and it was way off. So since I have swapped the entire X axis setup. I am looking at the y axis now. Bed is actually making a rougher sound and I just now noticed one side of my bed end is broken. The smooth rod is not fully supported, well enclosed. This might be contributing to the slop? So I will MacGyver it and print a new one. Going to swap out the pillow blocks back to the ones with the bronze bushings while I am at it. After all of this if it still is printing ovals I'll replace the y axis driver and motor as well. I have the extras sitting here. Anyone know where I can find the stock STL for the bed end?
     
    #6 SteveDjarrell, Oct 12, 2016
    Last edited: Oct 12, 2016
  7. Chuck Erwin

    Chuck Erwin Active Member

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    Rigmarol and SteveDjarrell like this.
  8. SteveDjarrell

    SteveDjarrell Active Member

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  9. Rigmarol

    Rigmarol Well-Known Member

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    Chuck, thanks bookmarked!
     
  10. JoshYourITGuy

    JoshYourITGuy Active Member

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  11. SteveDjarrell

    SteveDjarrell Active Member

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    20161013_222053.jpg
    OK, think I made it worse. In replacing the bed end I found both were broken. So those are fixed. I switched back to the bronze bushings. I also added a tension wire on the other side of the bed. The extra holes for the belt block, those now have a tension wire matched to the belt.


    Everything moves freely. All belts are tight. X axis driver and motor changed. Will do the same for the y next.

    S3d is slicing fine. Running at 33mm vs 60mm does produce a little better part. Still not right.

    Anyone have any other +suggestions?

    Sent from my SM-G935V using Tapatalk
     
  12. SteveDjarrell

    SteveDjarrell Active Member

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    Well, I am officially Stumped. So after everything I have done circles are still slightly oval'd along the Y axis almost perfectly. IT appears to me that the Y axis is moving to far? So this is what I have done. I had a bunch of parts laying around... I did play around with belt tension and never found anything that really made a difference so right now they are snug but not banjo tight.


    X axis

    1. Went back to stock x-carriage and stock bearings. no binding.

    2. Replaced Stepper Driver and tuned

    3. Replace motor

    4. Replace wiring from stepper to driver.

    5. Replaced Belt
    Y Axis

    1. Replace Motor

    2. Replace Driver and tuned

    3. Reverted back to stick pillow blocks and bearings. No binding.

    4. Replaced Wiring

    5. Replaced Belt

    6. Bed end was cracked so printed new end and attached. Seems slightly small (1-1.5mm) and the holes for the rods were oval'd. But does not cause binding.
    Firmware

    1. Flashed back to stock lead screw firmware with only change being steps for the titan extruder.
     
  13. SteveDjarrell

    SteveDjarrell Active Member

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    Forgot the photo...
     

    Attached Files:

  14. Geof

    Geof Volunteer Moderator
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    The set screws on all the pulleys are tight and used loctite to ensure ? Does it happen on any circle you print ? Id and OD? What slicer ?
     
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  15. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yea, picture doesn't tell it. How far off are we talking?
    About the best you can do beyond what you have done (assuming everything mechanically is working correctly) would be to tweak the steps/axis to dial it in further -- that is not something you normally want to do.

    Why not?

    The steps/axis are determined mechanically (by the design) and there will be limits (given the design and components) for how accurate you can expect it to be.

    BUT I have seen folks dial those numbers in to achieve better tolerance. You are going to be on your own there :)
     
  16. SteveDjarrell

    SteveDjarrell Active Member

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    I am using S3D, All set screws are tight. I did not Loctite them but they have all been checked multiple times. Seems to me that if I do something with a wall that the ID is more affected than the OD. I have tied rotating prints 45 degrees and the circles have the same oval shape always staying on the y axis. This is very slight and maybe I am being too picky. on a 20mm round cylinder it ranges from 19.77mm to 20.22mm. The larger number being on the Y axis. I am really stumped. I did try adjusting the steps to see and I can get it almost perfect at 20mm but does it scale? Meaning would that give me a good print at 150mm?
     
  17. Geof

    Geof Volunteer Moderator
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    I have never adjusted the z y or z steps. Hopefully someone that has done this can pop in and answer that for you.
     
  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Probably. It would totally depend on why it is not correct in the first place. If it IS a mechanical issue* it could be something loose which will vary over time and then it will not stay corrected once you fine tune it,


    *and it really has to be something mechanical that is off.
     
  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    In all fairness though some of the tolerances on this style of printer are going to be wider variance than you might have accounted for... just by nature of the printer. If you wanted absolute certainty on tolerances then DLP/SLA would be a better fit than FDM :)
     
  20. SteveDjarrell

    SteveDjarrell Active Member

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    I completely agree it has to be mechanical at this point. I am just at a loss, I will be going over everything one more time. I realize the tolerances on this system are not perfect by any means but I was getting better or closer measurements a few weeks ago before all of this started. And to be honest I never noticed cylinders being oval. I would think that it has to do with the Y axis, I have printed a single bed end that appears to be just a little small. Only thing I can think of. I replaced all the linear bearings also. I am keeping this thread updated simply incase something jumps out and to aid anyone else in the future for what not to do. My OCD will not let me stop until this things is running perfect again :) I really want to do something else...... Thank you though, I appreciate all the ideas and posts gentlemen.

    -Steve
     
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