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I have Ender 3 which I bought in 2018.

Thigs I have done so far to the printer;

  • Installed a BIGTREETECH SKR V1.3 board.
  • With TMC2130 drivers.
  • Flashed the new Marlin 2.1.1 (Configuration.h and Configuration_adv.h)
  • Installed and configured ANTCLABS BLTouch v3.1
  • Prints are sent through a Raspberry Pi 3b+ with OctoPrint 1.8.6
  • I have mounted the heating plate on standoffs (not on springs).
  • On top of the heating bed I have put a glass plate as my print surface.
  • Leveled the X gantry (as per this video).
  • Did the "probe Z offset wizard" (as per this video).
  • Did ABL Visualizer update.
  • Enabled baby stepping, but did not see an option when double clicking nor I see a menu item in "Tune" option.

Issue;

I'm having trouble getting my first layer perfect. As the front prints are loose and back prints are squashed to the build plate. Here is the first layer test print file.

If what I understood so far about ABL is correct, when printing with a uneven bed surface, the z height will be adjusted according the probed data. But in this test print looks like it is not being compensated.

Below is how my visualized bed mesh looks like (with those fixed standoffs). enter image description here enter image description here enter image description here

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    $\begingroup$ 0.7 difference is too much - tram it better! $\endgroup$
    – Trish
    Nov 28, 2022 at 7:32
  • $\begingroup$ Hi Hansa, welcome to SE.3DP. Nice question, and well presented $\endgroup$
    – Greenonline
    Dec 1, 2022 at 11:46

1 Answer 1

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What can be read from the visualization of your bed geometry is that the left side (when facing the printer) of the X-axis is lower than the right side, so your plate is tilted.

If what I understood so far about ABL is correct, when printing with a uneven bed surface, the Z height will be adjusted according the probed data.

Yes, true (see Automatic Bed Leveling (ABL) with a sensor (BLTouch, inductive, capacitive), how does it work?), but that is a sales pitch, you don't want the bottom of every print to be skew! A probe is not meant for those skew plates it should be used for local dips and dents in the build plate. ABL (or UBL, see What is ABL or UBL? Is this the same?) will scan the geometry of the build plate, but you still need to supply a bed as level as possible. With the bed geometry results from the question, you need to level better! You should either shim the left side standoffs so that the bed is more level. A probe shouldn't have to compensate for the a skew plate, it can, but it should not. It is either wrongly trammed, or there is a hardware problem that is commonly found on these printers (X gantry is not parallel to the bed and has play, due to the cheap roller system and simple single driven lead screw design). This is described below (to make a more complete answer) so that other readers that run into similar issues can use this information

A possible alternative is that Looks like there is something wrong with your X-gantry, make sure the X-gantry is parallel to the bed, e.g. as seen in the following image:

enter image description here

This could be a result of lack of maintenance, considering the printer is from 2018, the frame needs to be checked. At the moment, the right side is closer (high X values), so either your bed is higher on the right side, but more likely (as you use fixed length stand-off's) the X gantry is tilting down on the right side (when facing the printer) and therefore reporting closer to the bed as if the bed is higher to the right, e.g. see adapted schematic:

enter image description here

This is a very common problem with the Ender 3 type, especially the single lead screw driven designs. To fix this permanently, installing a second lead screw is advised. As a quick fix, you need to inspect the complete roller system on both Z-axis posts and retighten them.

An excellent example of the problems with the X-gantry is shown in this video:

This video is a very good example for the problems with the portal style printers that use rollers for guiding the gantry. Look at the play in the (X-Z) gantry, this would cause the exact same bed visualization as posted in the question (note that the video is centered on the installation and software changes, but the printer used has seen better days and should have been maintained prior to installing bed leveling).

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  • $\begingroup$ Hello @Oscar, your answer is very complete; however, for me the bed is well trammed, check it out i.imgur.com/EILFaJj.png there seems to be a little warp on the left side of the table, but thats what the ABL is for, right? Anyway my case is exactly the same as the OP, all the troubleshooting steps, same printer, same board with the difference that Im using a CR Touch instead of BL Touch, and my bed is well trammed. With all that, my Z rod doesnt move while printing 1st layer, I checked EEPROM to get the bed mesh and it was there, ABL was enabled. Do you know what could be the cause? $\endgroup$ Jun 25, 2023 at 6:32

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