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Solved Terribly Inconsistent Printer!

Discussion in 'Troubleshooting' started by Ender, Feb 21, 2017.

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  1. Ender

    Ender Member

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    I have the ROBO 3D R1 Plus printer. I have added a PEI sheet and the XXL printsolid lcd. My biggest issue with this printer is the bed leveling and z offset inconsistency. I have been battling this problem for around a month now.

    First problem is the bed leveling. I moved the nozzle to the left side of the bed and get the nozzle to where I can just slide a piece of paper under it and the moved the nozzle to the right side and adjusted the threaded rod with my hand so that the nozzle is the same height off the bed on each side. I started the print and when it was laying down the first layer it wouldnt print on the right side but would print on the left side(because the nozzle is too close to the bed on thr right side). I adjusted this by using trial and error turning the right threaded rod till it produced a consistent first layer.

    Which sound like the bed leveling program is jacking everything up, how can the X axis be level before a print and not during a print??

    Secondly,
    I spent the last couple of days fine tuning all of the print settings for the different filament including the z offset. I printed some cubes and calibration ring and had it perfect at a z offset of -0.03. I let the calibration ring finish and then I removed it and started a new print, now the nozzle is dragging on the bed during the first layer!! I backed it up to 0 and it is still dragging on the bed. This also happens quite often.

    What could be the deal? It turns printing into an all day affair because what works one day might not work another.
     
  2. Geof

    Geof Volunteer Moderator
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    I would have to guess that the micro switches on your z axis may be loose.

    Typically you want to check them and make sure everything is tight and seated properly, then do a paper leveling then you should get consistant results that you can offset for. If your unable to account for the high left side you can mechanically shim the bed on the low side to get it even and try that. IF that still doesn't work we can direct you to mesh bed leveling firmware upgrade out friend @WheresWaldo has set up for us (its awesome). But one thing at a time :D
     
  3. Ender

    Ender Member

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    Thank you for the quick response. I would like to also note that one day my Y micro switch was reporting triggered when it wasn't. I unscrewed the switch and unplugged and replugged the wires back in and then it started working fine. I have been able to account for the higher left side by turning the rods by hand before a print, but it doesn't seem to stay and I don't have all day to print calibrations circles over and over till it is level.

    The micro switches on the z axis seem to be secured in place. I will do the same thing to them that I did on the Y axis.
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You can make sure they are both positioned as close to the same as possible. That will help. If one is riding higher up that the other (or either one is loose and not seated well) then the leveling will be crap.
     
  5. Ender

    Ender Member

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    I got the micro switches screws tightened up and now my z offset is at 0.1(this used to be 0 when I first got the printer). I have had it at this height before but when I go to use the printer again it starts printing to high off the bed. But maybe that was due to a loose micro switch. The X axis is still higher on the right side than the left when manually moving the nozzle. But when printing I get a pretty even layer that is really stuck to the bed. I still don't think it should be this way...

    I have a few things I have been wanting to print so I will report back in a few days(or less if it happens again) on the consistency of the printer.

    And I have noticed that the board under the bed is sagging big time and it touching the Y axis stepper motor. Should I fix this and how?

    Thanks for the suggestions!
     
  6. Geof

    Geof Volunteer Moderator
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    The cork you can lift the bed up and apply more HVAC aluminum tape.
     
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  7. cain

    cain New Member

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    make sure it is sitting on the rod nuts properly, this can throw the bed lvl off too. where the carriage sits on the nuts for raising and lowering.
    can cause the switches to prematurely click as not fully compressed vs each other.
     
  8. Rigmarol

    Rigmarol Well-Known Member

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    When leveling with a piece of paper I have experienced that I have to do a sort of back and forth process:
    -Using my hand to turn the virtacal screwrods I set it snug on the far left to a piece of printer paper.
    -Using my hand I move the hot end to the far right noting if it digs into the bed or not and adjust as needed.
    -Using my hand I turn the right rod until snug on the paper.
    -THEN I REPEAT the process starting at the far left again.
    -I have seen it take a number of tries to get it right. This is for my R2 Plus and yours may be different.
     
  9. Perry Genovese

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    to get my bed level was a nightmare. I use a depth gage on my digital caliper. I use the horizontal rod of the x-axis with the bed centered under it and probe the distance to the bed. I twist the leadscrews until both sides are equal distance from the bed. Then I print 5 20x20x2mm cubes....one in each corner of the bed and 1 in the center. Measure the thickness of each one and found the bed was off from the back. Bed leveling does not account for it obviously as before the print it auto leveled and the cubes were differrent thicknesses. So....loook at the magnets and find they are not consistent. My routine then was applying small squares of tape to the lowest magnet to raise the bed on that corner and reprint. Measure....rinse and repeat adjusting other magnets as needed until the cubes are as close as you can get them. Mine usually vary in thickness from 2 to 2.08mm when I ;m done and I decided thats close enough for melted plastic on a hobby machine :) Different tapes have different thicknesses too so if you have a variety on hand like I do you can actually dial it in. Takes a while and if you tend to use the entire bed for either large prints or multiples it very well worth it.

    If Waldo's firmware addresses this I would love to see it as well but I can't see front to back Y adjustments via Z as its cruising back and forth to try to print on an unlevel bed.

    Thiose are my 2cents and my technique which works for me pretty good. As usual I probably did it the ultra hard way :)
     
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  10. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Here is the big issue with Marlin 1.0.0 and auto-level. It is planar! Your bed must be 100% flat in order for it to really work properly. In simplest terms (not exactly how it works but this description will be close enough to illustrate why it isn't working) The 9 points Marlin measures is placed in a grid and then a single plane is created to best fit that grid. That means some points will be above the grid, some below and some right on plane. That is it, not enough lowing for the high spots, not enough raising on the low spots. The more level your bed is the less this affects your final print size.

    Now Marlin 1.1.0 (not used in the R1, but currently the basis for the C2/R2 firmware) does something different. If properly configured each section of the grid is treated independently from the others and a plane is fit to each section (again, overly simplified) the adjustments then can better follow the bed when it is not uniformly flat.

    A second complication applies when you use auto-leveling, the probe that Robo used in the R1, while ingenious, suffers from a lag in triggering and in flex from the bed material. This bed flex and resulting lag is greater at the center. The center is the furthest from the four points that hold the bed in place. Anything printed on the edges close to the magnets will have a first layer that is not the same as if it were printed in the middle. Z Offset is used to compensate for the lag in endstop triggering but it is a single adjustment that is applied to every point in the grid equally.

    Manually configuring that adjustment matrix (MESH) works better since you are only dropping the hotend onto the bed until the feeler gauge can slide under it with a minimum of effort. You are not asking it to trigger the endstop at every point in the grid, so it better represents the actual plane the bed is on without the influence of trigger lag or bed flex.
     
  11. Ender

    Ender Member

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    Thanks for all the suggestions everyone!

    I have been printing stuff for a few days now and have rotated between two different types of filaments with my printer being much more consistent. I have only had to change the z offset once. While re-tuning it from the last inconsistency I originally settled on on .1 mm but then realized the first layer looked very uneven like it was too close, so I backed it up to .12 and this worked out perfect. However, a day and a couple prints went by and the nozzle seemed a little too far off the bed. I lowered it to .1 mm and now it is printing similarly to when it was at 0.12mm.

    Still seems a little finicky but not nearly as bad as before, I am no longer spending most of the day tuning the printer and am actually printing! :)

    ps: It still seems weird that the nozzle can touch the left side of the bed and not the right side but yet it prints evenly. I guess as long as it is working than I shouldn't worry about it.
     
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  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    As long as your difference across the bed is less that the first layer height it is rather moot.
    The autoleveling is helping and there may be a minor difference in the x crossbar from side to side.
     
  13. Rigmarol

    Rigmarol Well-Known Member

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    I've resolved this (temporary) problem in the past by pausing the print then manually turning the one of the threaded rods ever so little and restarting the print to see if it resolved it. It took only a very small turn barely noticeable.

    I eventually fine tuned my printer and haven't had to do it this way for quite some time.
     
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