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Partial Answer Z Axis Wizard Glitch Causes Extruder to Smash into Bed

Discussion in 'Troubleshooting' started by Chair, Jan 24, 2017.

  1. Chair

    Chair New Member

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    Ever since I got my C2 I've noticed that the Z Axis Wizard doesn't always work right. When I first adjusted the Z axis it placed the print bed reasonably close to the nozzle. After a few times however suddenly the printer didn't move the print bed up as far. Instead of reading ~4.9mm it read ~17mm. It still worked well. I just had to tap the touch screen about three times more to get the bed in the right spot. One morning I used the Z axis wizard and it gave me a reading of ~13mm. I thought nothing of it because it had changed before with no problems. I started printing and came back 20 minutes later to find that the bed had smashed into the nozzle and had pulled it out of its mount (I'm new to 3D printing so I don't know all the terminology).

    Is this a known glitch or am the only one who has experienced this?

    Also would this be able to damage the print bed? I've found that when slightly pushed, the front of the metal print bed moves up. I didn't notice this before this happened.

    It all still works but I'm concerned it will happen again.

    Thanks.
     
  2. Geof

    Geof Volunteer Moderator
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    Hello @Chair , Not many users( none of us older guys) have a C2 and very few have technical experience with them. I'd recommend that you give Robo a call and see if they can help you out, they dont frequent the forum, just us users. Sorry I cant be of more assistance.
     
  3. Eric Albert

    Eric Albert New Member

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    Just got my C2 this week. Having issues with the Z offset adjustment too. Noticed that one of the bed magnets was not seated in the socket as much as the rest - I took a screwdriver handle and pushed it back into place like the others. I have done the Z offset adjustment and get values from 4.8 to 5, but when printing a file the nozzle clearly crashes into the tape and you hear the extruder motor clicking from that situation where nothing is getting extruded. I am using the 1.1.1 software on the C2. I'm going to try something other than "paper" - like a business card. I'm thinking the leveling wizard routine is not calculating the offset correctly because the number assumed for the thickness of the paper is not right. So far I haven't damaged the plastic build surface underneath the tape, but I did destroy one tape patch already... Wish there was a way to manually dial in the offset from the control panel and store it.

    UPDATE: I've found that using the cardboard backing of a battery package (a little thicker than a business card) seems to work pretty well. Definitely not a sheet of typical printer paper. I'm up to the latest software too but still need to use the cardboard piece to get a working Z offset (about -4.5)
     
    #3 Eric Albert, Feb 23, 2017
    Last edited: Mar 2, 2017
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I did today try to print a full-bed model and noticed that right-to-left my bed was unlevel by a fraction. Probably 01.mm - 0.2mm
    I added a layer of double-backed tape around that edge, built up to just bump that a tiny amount and it is fine. It was not enough to matter in the middle of the bed and only a print that ran full-size would show it. Even then only if you were paying attention :)

    I need to come up with a better way to more permanently level that bed. So shims or something that can stay with the bed. Right now the stack of DB tape layered along there is doing the trick.
     
  5. Ed Ferguson

    Ed Ferguson Active Member

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    "I need to come up with a better way to more permanently level that bed."

    Mark - Do you have a photo showing how the removable bed attaches to the plate below? I know it uses magnets, but can you see a possibility to add a set-screw adjuster at each corner?

    If my bed droops (on my R2 when it ships), I'm going to the drawing board to make a solution. I feel the Marlin leveling firmware should be for final accuracy tweaks, not to overcome a fundamental mechanical issue like the 5 degree droop one poster measured.
     
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  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I can drop in a photo after this print finishes. Either in 1 hour or 7 hours depending on which estimate in OctoPrint you believe. :) I am sticking with the 1 hour one

    The set screw idea is interesting. The magnets are a ball-joint style arrangement with the magnet being the ball and the joint on the bottom of the bed. A set-screw through the bed at the point of the ball would work -- if there is enough plastic for it to thread through.
     
  7. Ed Ferguson

    Ed Ferguson Active Member

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    Interesting. I'm curious to find out how the heated bed on the R2 is constructed. I have a CNC lathe and CNC mill, so if I need to make a solution I can easily make several for others.
     
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  8. Geof

    Geof Volunteer Moderator
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    I use self adhesive shim stock in the "hole" causing issues with my sigma (same magnet set up)

    Even 2500.00 printers need love ;)
     
  9. Eric Albert

    Eric Albert New Member

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    When I look at the front of the print bed on my C2 it almost doesn't look parallel to the mounting plate. But if so, why doesn't the auto level get it fixed? Also the magnets go on acorn nuts that are mounted to the plate. Maybe the acorn nuts could be raised a little to compensate. I've also noted through measurements that although there is no fixed front or back for the build plate, it does matter which side is in the back. Plus as someone else has noted, there is a lot of play in the platform if you lift it gently at the front. I hope the R2 does not have these issues...
     
    #9 Eric Albert, Mar 5, 2017
    Last edited by a moderator: Mar 5, 2017
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Autolevel comes in several flavors and the one Robo is currently using requires that the X axis be really level from the start or the rest will not help. Frankly, the one they are using is not the best of the bunch since the ABL routine just generates a flat plane across the 9 points (when everything works) and the MESH version will actually correct for unlevel sections within the bed area.

    Since they are on 1.10 of Marlin you could try with MESH leveling. I have not done that yet, but it is on my list. I was waiting for 1.10 to get out of development and then merge in the changes with what Robo has. You could try MESH with what they have on there now.
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Adjusting the nuts was something on my list to try as well :)

    Mine is definitely sloped just a bit from one side and that might be all I need to relevel.
     
  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I will test tomorrow and see if the placement if the plate affects the slope as well. That would totally bite (since it is not marked) and yet totally be par for the course :)

    Sent from my SAMSUNG-SM-G930A using Tapatalk
     
  13. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Something as easy as changing to Bilinear in the current C2 firmware (Marlin 1.1.0 but I think it's RC6) If Bilinear isn't there you would have to migrate all of Robo's changes to RC8 or the bleeding edge RCBugFix. If I had a C2 or R2 I would do it for the group but I am not planning on buying either in the foreseeable future
     
  14. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I intend to do it when Marlin 1.10 goes release mode at a minimum. If I have time before then I will try sooner.
     
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  15. colton81

    colton81 Active Member

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    Ive been having issues leveling my bed as well on my C2 i took a ruller and stood it on its edges acros the bed and the center of the bed was warped up wich intern was causing issues when printing. I tried applying heat and bending it straight but it would just warp back to how it was. I had to end up getting 80 grit sand paper and sand the crap out of the bed to get it fairly level. Which helped alot but im noticing now that the medal piece that the bed attaches to seems to be bent slightly in two cornes so no im having to try to shim it. The problem is the auto leveling sucks. Going to try to call robo today if i get a chance and get them to get this replaced.
     
  16. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    I already did a lot of this work for you. I played around with their GIT and migrated the configuration to a not so current December 2016 RCBugFix (post RC8) as well as incorporated the pins file for the C2 as a proof of concept. Of course I don't know if it works but you are welcome to look it over. It is post #944 in the R1 thread for Marlin 1.1.0. It might be easier to start from there as I left Marlin 1.1.0 vanilla.
     
  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  18. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    @colton81 once the injection molded bed shape has set, applying heat will only temporarily fix whatever warp is there. I had a hard mouse pad that developed a crown in the middle after about 7 years of drying out (leaching plasticizers) andf I continued to use it for 3 years after that. I could heat it with my heat gun while under pressure and it would return to being flat, but by the end of the week it had the exact same crown in it. It is just the nature of plastic to behave that way.
     
  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    What they have is (slightly) better than none at all. Hopefully this will improve, but they have stuck with pretty much the same thing since the R1 first added it.
     
  20. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    To add to what @mark tomlinson has said, the version of auto-leveling used can only account for beds that are 'off plane' not warped. Funny thing is, the version of the firmware they have used has a better version of auto-level already in it and Robo chose not to use it. The newer version will allow a warped bed to better align itself with the extruder, there is even a FADE construct that allows you to gradually incorporate the leveling adjustments over several layers so it's not all in the first. Even I haven't played with the FADE feature and I tend to try everything new.
     
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