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Z Axis needs calibration every other print???

Discussion in 'Troubleshooting' started by rogwabbit, Aug 30, 2014.

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  1. rogwabbit

    rogwabbit New Member

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    Anyone else have this issue? I noticed the rod on the right side was loose connecting to the stepper so I took it apart and added more pipe thread and pushed it back in and it seems pretty tight now. But after a couple of prints, it's printing off the bed on the right side and too close to the bed on the left side. The first 30 prints from this machine were perfect but now it's getting flaky if I can get the first layer down. Does anyone else have this issue? I checked the rods and seem fine, not moving when I hold the coupler and try to turn the rod. I can't figure out how to make this thing stay callibrated. If I have to re-calibrate every 30 prints I would be ok with it, but every other print is not going to work for me. Any help would be awesome. This is the new one with the auto bed leveling so it should just work to my knowledge but there must be something off.
     
  2. SteveC

    SteveC Well-Known Member

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    It's unclear if you are doing this but have you releveled the Z left/right? This is done by turning one threaded rod or the other until the nozzle to bed distance is even on both sides. (Unless that is what you mean by calibration.)
     
  3. rogwabbit

    rogwabbit New Member

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    No. I calibrated both sides manually with a 3-4-5 block against the rail and the bed on both sides while the head is in the middle. When I say calibration, I mean going to configuration and clicking on configure next to automatic calibration and using the paper to set the z travel. It's the only thing that seems to work.
     
  4. SteveC

    SteveC Well-Known Member

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    Sorry I don't have the autolevel kit so maybe I am missing something. Are you manually rotating the threaded rods to level the X carriage in this process? Don't you need to do this to get it in the ballpark for autocalibration?
     
  5. rogwabbit

    rogwabbit New Member

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    This is what I have done.
    Take a 3-4-5 block and place it on the bed and find out which side is higher comparing the front bar / guide. I take the lower one and use the controls to do the same thing as the paper calibration does. I set it so I can just slide the paper out. Then I adjust the higher one to match that. When I am done I can hit the .1 on the Z and it will be on the paper or off the paper on each side. I figure that is close enough?

    That part is easy. The next part I click configuration in matter control then click configure next to automatic bed calibration and do the paper calibration with the wizard.

    Then it prints ok for a few prints. After 2 prints I have to run the automatic bed calibration with the paper all over again. This part is annoying. I think I should not have to do this every other print. I am not sure how to fix it. I know I need to do it again when the nozzle starts scraping the bed causing clumps of plastic to bead across when printing the first layer skirt.
     
  6. SteveC

    SteveC Well-Known Member

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    No. Someone else please help me here because I don't have autocalibration. If one side is higher you should adjust either the left or right threaded rod to level the X carriage. I understand if they are very close and you can rely on auto calibration to do dynamic adjustments to Z. Otherwise you should at least get them in the ballpark of being level. I understand that this probably has nothing to do with your system seemingly loosing the autocalibration information. I'm sure someone will chime in to help.
     
  7. Ziggy

    Ziggy Moderator
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    I think there might be some mixup here because when you are using MatterControl there are two different "auto leveling" functions available

    One is the so called "wizard" in MatterControl where you manually probe 3 points on the bed using a piece of paper and moving the extruder up/down as needed. This process allows MatterControl to figure out how to make the bed look like it is level during the print. I don't use this process but I think MC looses its wizard settings if you close/open the application.

    The second is the "Auto Bed Leveling" built into the Marlin firmware. To use this, you must have the Robo Auto Leveling Z nut switches and use the gcode G29 and a measured Z offset value in your print start gcode. When the G29 command is given, Marlin probes the bed at 9 points (this is the usual setting), calculates the real heights using the Z Offset (which is set using M565 gcode) then figures out how to modify the print gcode so the Z height stays level across the bed. In this case the only thing Marlin needs every time you print is the Z Offset value (which is in your start gcode for every print)

    You can use one or the other but not both at the same time.

    I think from your earlier post you do have a Robo with the Z nut switches. In that case I think you will find the second process above will work much better for you.
     
    #7 Ziggy, Sep 2, 2014
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  8. rogwabbit

    rogwabbit New Member

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    Interesting... Because my observations are a bit different? The wizard in Matter Control is located next to auto bed level enable button. Its labeled configure. It just asks you for the paper and uses a total of 3 points. However in slice settings, when clicking about show all settings there is a pre and post gcode box with commands for the printer. Those codes have the g29 and m565 you are referring to in the pre section. But curious as it seems I have yet to see it go through a 9 point probe of the bed. Mine probes the bed 3 times at the beginning of every print, always has! First one is at home position, the next one is the far right side and the last one is the rear left side.

    How would I go about determining if my Z offset on the m565 value is correct out of curiosity? Maybe I should change the MatterControl auto bed setting to disable, and just make sure my pre gcode stays there? Is it possible that Matter Control is trying to compensate and so is the firmware causing my issues? It may have started after I upgraded Matter Control now that I think about it. I think when I first installed it the button was set to disable, but now it's enabled. I'll have to experiment a bit with these settings and see what is causing this.

    I would like to know how to tell it to to the 9 point check also. Could I do this manually somehow with a terminal window?
     
  9. rogwabbit

    rogwabbit New Member

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    Update.... Success... For anyone that has the auto bed leveling (All new ones) the Matter Control bed level has to be disabled!!! I am happy to report everything is back to normal from what I can tell now.

    One quick question, how can I calibrate the extruder????? I think it's extruding too much but then again I am not sure how to tell. Should the first layer be completely flat? Mine seems to have tiny beads on each side. That is why I'm asking. I think it may be too much through the nozzle. How wide should a single line on the first layer be?
     
  10. Ziggy

    Ziggy Moderator
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    Yes. It will be simpler to use the G29 gcode. Somewhere in the forum there is info how to calibrate the Z Offset for M565.

    Yes. You can have MatterControl doing the leveling or the firmware - BUT not both at the same time.
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    See @tesseract famous photo.

    Either too low or too much extrusion rate (it sounds like).
     
  12. Kaan

    Kaan Member

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    I'm pretty much at the same place, G29 probes at 9 points, but is it the MatterControl that reads the output data, and modify the G-code's it sends to the device?

    Because I've tried MatterControl's start script with Simplify3D, probed all right, but didn't print as if it was auto leveled
     
  13. Ziggy

    Ziggy Moderator
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    If you have MatterControl Auto Leveling enabled, MatterControl itself will adjust the Z heights in the gcode it sends to the printer - that's how it works to compensate for an uneven bed. You can read more here

    http://www.matterhackers.com/articles/mattercontrol-guide-to-automatic-print-leveling

    But

    If you also have auto bed leveling enabled in the Marlin firmware, the firmware will probe the bed (ie 9 times) then start adjusting the the Z heights during the print in the firmware to compensate for the uneven bed

    So

    If you have BOTH MatterControl and the Marlin firmware trying to compensate for an uneven bed, result = big stuff up.

    You must disable either MatterControl or the firmware bed leveling.

    IMO it is best to disable MatterControl auto bed leveling. The firmware bed leveling function is much better and you can print from SD Card on the printer.
     
  14. Kaan

    Kaan Member

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    Thanks for the information, I think I've got my best prints with both enabled :) (MatterControl was pretty decent actually, with it's slicer and minor issues aside, like not having an efficient kill switch, I might switch to MatterControl and try to get Slicer to work with it, my initial minor efforts failed)

    At Simplify3D, I generally need to provide a Z offset myself, this leaves only the unlevelness, works for small prints

    I guess I might solve my issues by taking the starting G-code here: http://forums.robo3dprinter.com/index.php?threads/z-axis-endstops-usually-fail-not-always.3135/

    And setting M565 Z1.1 (1.1mm offset)

    It might be good if we can pull together a G-code sequence, that when executed, probes the bed, and verifies the auto levelling by traversing the entire bed at +1mm Z

    I generally do this crudely by printing something, but obviously it's an overkill and very time-consuming (just start printing something, and cancel)
     
  15. Peter Krska

    Peter Krska Active Member

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    Is it possible to first manually level the bed using the two hand method holding the z rods and turning them as the print is laying down the first layer, THEN, set the z axis height screw, THEN set the auto-Levelling in and do the test?

    I use the beta version, manually setting the level and then adjusting the z axis height
    Screw so that it's consistent throughout.

    It's not that hard to get it right if it's done that way. In fact I've gotten so good at it, I can level it by eye moving the extruder across the bed viewing the height.

    Relying on something like software to do it when it's so out of alignment already, you might as well do it manually first to get the feel of where It needs to be.

    Once you have it dialled in, you'll better understand the height requirement.


    Sent from my iPhone using Tapatalk in Canada
     
  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yea, I agree, your eyeballs get calibrated pretty quickly.
     
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