Help to decipher the Mesh Grid Compensation results



  • I just ran my first mesh grid compensation and these were the results:

    alt text

    If anyone could help me read these tea leaves, I'd be thankful!!!



  • This post is deleted!


  • you lower the bottom right and raise the top left.

    it could also be a wobbly bed.



  • Will do! Dumb question. Which two corners of the image make up the front edge of the build plate?

    alt text

    Thanks!



  • for me its 3-4.



  • have you done a bed leveling test with a sheet of paper?



  • Not since I have set this up. I did it all the time with my MKS Gen L board. In Marlin there was a procedure perform a manual level...I'm still learning RepRap! Plus, now since I have gone full on auto level, I took out all of the leveling screws and put a steel tube/post in each corner. That is why I am a tad bit surprised it is off that much. I'm going to check my X Gantry as well.



  • I just started with Duet and GCode. Here's a bit more info that I just stumbled through.
    Sometimes the answers from experienced users assume we already know much more than we do (for me anyway).
    When you look at the graphic, there are XYZ arrows at one corner of the grid. Those correspond to the corner that is your origin...the lowest X and Y values in your scan setup.
    Place your cursor over the grid. Rotate the wheel on your mouse to enlarge/shrink the image. Cool. By using the right and left buttons you can rotate and tilt the image. Rotate the image til you get the origin (arrow icons) where you want it. For me, that was lower left.
    The next helpful tip is to use the "Top View" button on the lower right to see the bed flat from the top. Each scan point is highlighted with a white dot. Place the cursor on that dot and you will see the actual Z value at that point. Make a chart of the four corners and write down the values. As you mechanically adjust your corners and then rescan the bed, you can do a final mechanical leveling - best done after a rough levelling with paper under the nozzle method. After getting your mechanical level dialed in, auto-leveling can take over for prints.
    Another thought. In my old 300x300mm bed (I have a used printer), the edges and corners were starting to release the PEI film. Since I almost always print in a smaller area anyway, I set the scan pattern well inside the edges of the bed to focus on the area most used. Can always be changed as needed.

    I changed over to three point bed support. Way easier than 4 point and worth the effort.
    See this:
    https://drmrehorst.blogspot.com/2017/07/3-point-print-bed-leveling-vs-4-point.html
    I didn't do his full blown mod, just went to three simple spring loaded posts. Works great.
    Seems that even with auto bed leveling, you should keep some degree of mechanical adjustment available.
    I think most of the above is correct.



  • @bearcattd, for orientation look at the xyz arrows in the graph, this is where the 0,0 point on your bed is.

    I went through similar process recently and ended up with this configuration, 4 adjustment screws, having in config.g the spec of the 4 screws (x,y, thread pitch), using a macro called Leveling which tell me how much to turn each screw, and when done, using the automatic mesh compensation as you do, then during printing adjusting babysteps up/down as needed and updating config.g accordingly so I don't need to repeat it.

    It's sounds complicated but much easier and consistent than paper style adjustment in Marlin.

    I don't have a link for Duet writeups that cover these features so hopefully others will chime in.



  • @bearcattd As "veti" said: 3 and 4

    Normaly the red arrow is the x-axis, green arrow ist the y-axis and the blue is the z-axis


  • administrators

    Does your printer have bed levelling screws? if so then I suggest you look at https://duet3d.dozuki.com/Wiki/Using_the_manual_bed_levelling_assistant.


Log in to reply