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Solved Bed leveling options. Which is the best?

Discussion in 'Troubleshooting' started by Oisin, Jul 31, 2016.

  1. Oisin

    Oisin Member

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    Hi guys. I am having a lot of trouble with my bed leveling. I believe the autoleveling feature is malfunctioning. Everytime I run it I get different values by up to 1mm despite the bed remaining the same. I really dislike how long it takes to get the extruder height above the bed right before every print. If I could hit print and have it work instantly I would be a happy man.

    So basically I want to make a change to the printer, but which is the best route to take:

    1) I came across this on thingiverse: http://www.thingiverse.com/thing:301715 made by Robo3D users and forum member Ziggy. Does it work? And if so, why does it work better than the two switches on the z-axis rods the printer uses as standard?

    2) Mark here on the forums recently mentioned "MESH leveling". Can anyone explain why this is different to current autoleveling method? And if it can be implemented immediately?

    3) Z-offset. I have wondered about this for a while. In my starting g-code I have the line "M565 Z-1 ;" but then in the Simplify settings under 'Global Offset Settings" I have the z-offset = 0.17. What is the meaning of both of these and how do they interact?

    Sorry if any of that was a stupid question. I would like to know the best route forward to get reliable and consistent bed leveling so I don't have to spend 35 minutes before every print getting the z-offset right.

    If you have any suggestions outside of what I mentioned I'd be happy to hear them.
     
    #1 Oisin, Jul 31, 2016
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    1. Unmaintained and outdated code changes required. Not a good reason to use Ziggy's method. Although the probe itself is not a bad implementation. If you must look at new probes then you should look at the work @jim3Dbot has done with the IR probe.

    2. MESH is like a manual hybrid of auto-leveling but you only do it one time, not for every print. It requires that you move the extruder manually until it barely touches the bed in a grid pattern. It remembers that grid pattern because it is saved to EEPROM. Marlin version 1.1.0 has included this functionality and is currently at Release Candidate #7 (RC7) and there is a complete thread on it here.

    3. Z_Offset is Z_Offset and if it is listed more than once in a gcode file only the most recently executed line is in effect. It is used with Auto-level to account for the fact the the Z_MIN_PROBE is triggered after the nozzle hits the bed, so we need to account for the difference in the real world measurements. The problem is that Z_Offset is globally applied and since the bed flexes different amounts in different areas of the bed, your first layer will never be 100% consistent.

    Personally I think that if you are trying to make your Robo as close to 100% accurate and 100% repeatable, you only have two choices. Use Marlin as is and try out @jim3Dbot's IR Probe

    or

    Move to the as yet unreleased Marlin 1.1.0 and use MESH leveling. The more accurate you are using feeler gauges and performing the initial leveling sequence the more accurate your first layer will become.

    There is a third option, use @jim3Dbot's probe and Marlin 1.1.0 with MESH leveling enabled.
     
    #2 WheresWaldo, Jul 31, 2016
    mark tomlinson likes this.
  3. Oisin

    Oisin Member

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    Understood. Thank you for the response, Waldo. Can I ask what you use yourself and whether or not it is effective?

    I will definitely look in to moving to Marlin 1.1.0 and I'll take a look at the IR probe you suggested. I would assume that if both increase first layer reliability then using them together would be a good call. I figure, why would they sell a printer with that bed area if you can't use the entire area at once? So there must be a way to get it to work.
     
    #3 Oisin, Jul 31, 2016
  4. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Personally, I use Marlin 1.1.0-RC7 w/MESH enabled. It is not a released version of the firmware. Some people might have issues with that. But I would not say that is the only answer. I am not sure using @jim3Dbot's IR sensor and MESH leveling at the same time would give you any better accuracy than just using one or the other by itself, just pointing out that it could be done. @jim3Dbot's IR probe requires no contact with the bed at all and as such is not affected by bed flex or the teetering that the X axis does from one side to the other on the Robo using the default auto-leveling. MESH does touch the bed, but you are in control of how much it does as the MESH is a manual process.

    It is totally up to you which you choose to use. I should not be a factor in that decision.

    As far as being effective, MESH in my case is 100% reliable. But please ask those using @jim3Dbot's IR probe and I know they will say the same thing.
     
    #4 WheresWaldo, Jul 31, 2016
  5. danzca6

    danzca6 Well-Known Member

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    I can confirm that the IR probe is great. I use mine and not having a probe that touches the bed anymore saves time and those little variances you would get for reasons WW mentioned above. Also no more pushing the filament into the nozzle on contact and leaving little bed boogers. Love it. You can now buy one from @Printed Solid at https://printedsolid.com/products/mini-ir-differential-height-sensing-board. These are Jim's. You will just need to do some firmware adjustments that are spelled out in his thread and print a bracket to mount it. Once setup, you just click print and it goes. I haven't used Mesh, but I agree the two together would make a great pair. The IR would only be used during the homing of the Z axis prior to each print, but again, no nozzle contact. Lets you use other build surfaces like buildtack that you don't want a hot nozzle touching. I haven't taken the time to start using RC7 of Marlin, but want to get the IR changes into the ABL version that WW posted for us. If that works, I might move on and try the Mesh version with IR. I will be sure to post the modified versions for the IR if I get the time to play.
     
    #5 danzca6, Aug 6, 2016
  6. Oisin

    Oisin Member

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    Bought mine a few days ago and am very much looking forward to getting it working. I'm also working on a post to document my solutions to many of the problems I've encountered with the printer and all of the modifications I've made to it. It'll be great to get that done. Hopefully it'll make for an interesting read.
     
    #6 Oisin, Aug 7, 2016
    danzca6 likes this.
  7. DobryG

    DobryG Member

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    Hi! What's your decision now? How you're doing?
     
    #7 DobryG, Sep 29, 2016
  8. Oisin

    Oisin Member

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    Hi Dobry. I'm still working on it but I think I've come up with something pretty good.

    1) I printed this http://www.thingiverse.com/thing:280974 to try to level the x-axis. I asked Robo support how I could be sure the x-axis was level if leveled against the bed if I ALSO wasn't sure the bed was level. Their response was 'I'm not sure'. Top notch expertise! I've levelled the x-axis with this anyway as I assume the bed isn't *too* misaligned if leveling from the centerline.

    2) I've gotten a Dial Indicator and printed the following bracket to hold it: http://www.thingiverse.com/thing:571047. I will use this to hopefully get accurate indications as to how the bed is tilted. I will shim whatever corners I need to with paper until the bed is relatively level and there is no tilt (my bed is warped too, so this alone will not be enough).

    3) The largest thing I've done is get one of Jimbots IR sensors. This levels the bed without touching it. I've managed to get that working with the new MESH bed leveling in Marlin 1.1.0. MESH takes 16 points on your bed and accounts for them when you print. It compensates for warp. WheresWaldo has done some amazing work with it and I plan to write a longer how-to post about exactly what I did to make MESH work with the IR sensor. It wasn't too difficult. http://community.robo3d.com/index.p...lease-candidate-7-for-r1-r1-plus.5806/page-35

    That's about it! I'm going to finalise the MESH leveling tonight and hopefully never have any more problems with bed leveling.
     
    #8 Oisin, Sep 29, 2016
    WheresWaldo likes this.

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