Mesh leveling for multiple extruders



  • I want to create a mesh for each extruder. I have piezos integrated in each of the 4 extruder mounts, so if either of the 4 nozzles touch the bed, the z-probe triggers. Testing repeatability, it's accurate and responsive, so mechanically and electrically everything works. Can someone suggest a correct way without hacking the init config file (remapping drives and extruders etc) – to create a mesh for each hotened. Presumeably I'd run G32 to use tool 1 to perform the dual lead screw adjustment -- which works fine. Then I've done G29 and able to create mesh for Tool 1, but not sure how to do it for Tool 2 etc.
    I can stipulate the X and Y soft limits for G29 which are accessible by all hotends.



  • I fail to see why you want a map for each tool?
    The map would be the same for each tool, the only variance between the tools would be Z height (and eventually X/Y offsets)



  • in theory for tool 1 and tool 2 yes – absolutely they're on the same Y gantry, tool 2 and 3 are on their own independent Y gantry, and in theory it should also only vary on Z, but since I have the ability to probe the bed with each tool, I would like to give them their own mesh. I already used the probing capability to figure out the Z offsets, so that's done.



  • oh and maybe I wasn't clear, this is a machine with is for 4 independent extruders –



  • I don't get it either. The mesh is to compensate for height variations of the print surface so why would you need different amounts of compensation for each extruder?



  • I can see setting different Z values based on each extruder but not for bed leveling? A crooked bed is a crooked bed. once you know how to flatten it then all of the extruders should use the same map. Unless the y gantries aren't parallel with each other, in that case I would indicate them in to all be parallel.



  • So, don't bother? – use one mesh from any arbitrary tool (tool 1 is easiest) and then just set the Z offset for the rest. I supposes I was trying to get a bit more out of the fact that each tool has a piezo in it



  • I stopped using mesh bed leveling long ago, just make sure your bed is flat, the piezo probe will ensure you always have the correct Z-height, the rest should not be needed 🙂



  • @whosrdaddy:

    I stopped using mesh bed leveling long ago, just make sure your bed is flat, the piezo probe will ensure you always have the correct Z-height, the rest should not be needed 🙂

    so what do you do instead for auto bed leveling? G32? I'm using it for lead screw compensation. I'm figuring g29 to create a mesh. It's a large bed 610mm – flat as it gets -- very small sag in the center -- the probe measures 0.1mm diff between center and edges.



  • yes only G32, I have a i3 like setup and the 2 screw calibration works flawless in combination with the piezo sensor.
    Whenever I startup the printer I will do a G32 because the motors will be out of sync anyway.
    My first layer is always correct now since I use this feature.
    If you have a flat bed then G29 is really useless…



  • @whosrdaddy:

    yes only G32, I have a i3 like setup and the 2 screw calibration works flawless in combination with the piezo sensor.
    Whenever I startup the printer I will do a G32 because the motors will be out of sync anyway.
    My first layer is always correct now since I use this feature.
    If you have a flat bed then G29 is really useless…

    how many points to do you use for G32 (in bed.g I suppose)



  • only 2 as I have 2 leadscrews…



  • @whosrdaddy:

    only 2 as I have 2 leadscrews…

    yea, that's only enough to sync up the lead screws, and that requires manually leveling the bed – sorta defeats the purpose of having a probe IMO.
    I just want to get it close by eye and then let software compensate for the rest



  • The probe is needed for accurate leadscrew compensation.
    I do use G29 to check that the bed is leveled, once the bed is leveled you never need to do it again.



  • so I guess, manually send the head to different spots and adjust – thought of that, but I basically have it pretty level as is -- but the machine is too big and bed is too big to get it perfect, and I'm after perfect -- I ran G29 on it 2 weeks ago -- and I had the entire bed STD was ~0.2mm -- so I have it close already. I'll try it again tonight now that things are more stable and secure. I now have glass secured to the aluminum, so all mechanicals are done. Time to level and calibrate the extruders for XYZ offsets



  • @kazolar:

    …................. I now have glass secured to the aluminum, so all mechanicals are done. ..................

    Is the glass toughened? I found out the hard way that the toughening process causes the glass to distort so plain float glass is better.



  • @deckingman:

    @kazolar:

    …................. I now have glass secured to the aluminum, so all mechanicals are done. ..................

    Is the glass toughened? I found out the hard way that the toughening process causes the glass to distort so plain float glass is better.

    I use borosilicate glass with PEI attached on top – never use plain glass on a heated bed, especially this big -- last thing I need is this thing to crack from heat. And it's flat -- absolutely flat, got it direct from the manufacturer who basically invented the process of creating borosilicate sheets -- they made it custom to my spec (if you're in US, they're the place to go for borosilicate glass, not some reseller who gets it from who knows where)



  • Lovely discovery yesterday – my Y gantries were not parallel -- out by 5 mm -- took some minor disassembly, and some end stop adjustments but now parallel to as low as my caliper measures.


 

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