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Unresolved 20mm test cube tolerance

Discussion in 'Troubleshooting' started by CEchols, May 2, 2015.

  1. CEchols

    CEchols Member

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    So I just installed an E3D V6 print head on my printer and the first few prints where terrible! after a few copies of the same object with the same settings they seemed to improve... (Id love to hear thoughts on why that could be :))

    Anyway I printed a 20mm test cube to see how its tolerances where and the X, Y, Z were 20.07, 19.74, 19.87

    Are those normal tolerances, or could I improve something?

    Thanks!
     
    #1 CEchols, May 2, 2015
  2. Mike Kelly

    Mike Kelly Volunteer

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    That's pretty reasonable. .13 on the height could easily be an issue with the first layer being too low. .26 is probably just measurement error and if you took some more measurements you'd get a range of values around 20.
     
    #2 Mike Kelly, May 3, 2015
  3. CEchols

    CEchols Member

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    What do you mean by measurement error? I am using digital calipers for measurement.

    Thanks!
     
    #3 CEchols, May 3, 2015
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You took multiple measurements around the Z axis and they were all exactly the same?
     
    #4 mark tomlinson, May 3, 2015
  5. Printed Solid

    Printed Solid Volunteer Admin
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    Mike's probably right. But... If you want to try playing around with it more, I'm guessing you're underextruding just a tiny bit. From your description of other problems, this may be due to temp being too low.

    By measurement errors, he means uncontrollable errors associated with the measurement or measurement technique, not that you are reading the numbers incorrectly.
    How you hold the calipers, how tightly you squeeze, how well they are calibrated, what the ambient temperature is, what the temperature of the plastic is, where exactly on the part you are taking the measurement, etc. The killer with digital calipers is that they put a lot of decimal places on them that far exceed the actual accuracy or capability of the tools. this is true for the serious metrology companies and even more so for the cheapos from harbor freight and what not.
    Here is is in even more words :p
    http://what-when-how.com/metrology/sources-of-errors-metrology/
     
    #5 Printed Solid, May 3, 2015
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  6. Mike Kelly

    Mike Kelly Volunteer

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    Performing the extrusion calibration is also a good idea if you need really precise prints:
     
    #6 Mike Kelly, May 4, 2015
  7. CEchols

    CEchols Member

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    Sorr
    sorry for the delay in responding... no I measure several places and the measurements differed across, but that was the most off.
     
    #7 CEchols, May 13, 2015
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I would say 'yes'

    Always, just depends on how much time, effort and money you want to throw at it.
     
    #8 mark tomlinson, May 13, 2015
  9. CEchols

    CEchols Member

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    I am going to try Mike's suggestion and watch the extruder calibration video. I will let you know what the result it.
     
    #9 CEchols, May 13, 2015
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Good start. That one is easy and straight forward. You can get a lot of return on that investment.
     
    #10 mark tomlinson, May 13, 2015

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