Auto Bed Leveling

The AON-M2 auto bed leveling feature compensates for bed irregularities by using a multi-point topographic mesh and tool Z offsets to compute a value that is then applied to the machine’s Z position, ensuring that the tool is always the correct distance away from the bed surface. This is especially critical when repeatedly cycling the plates from room temperature up to 200ºC and back again which can cause slight warping and deformation of the plate surface. The bed-probing process should be run every time your printer may undergo changes in dimensionality. This includes but is not limited to:

  • build platform changes
  • heater block assembly or hot end changes
  • significant temperature changes (> 10ºC)
  • machine relocation

AON3D recommends probing the bed before every print, however if you are running multiple prints consecutively without significant changes to the bed or tools, you may find it unnecessary to probe again.

If using both toolheads, you will need to probe the bed using both. This prevents any error that may exist on one tool from influencing the other, as well as ensuring that if one tool is out of service, the other can function normally.

Probing a Mesh

To create the multi-point topographic mesh, the machine uses the toolhead to probe the bed in a grid of points. The probed values are then interpolated into the topographic mesh. Each tool has its own mesh and Z offset and should be treated as an independent calibration. By default, meshes are set to a flat 20mm at all points, and the Z offset is 3mm. This results in the bed having a zero point that is 23mm below the Z end stops.

These default values are only present until overwritten! Once you have probed the bed, the mesh will be saved to the last recorded values.

The bounds of the probed area can be adjusted to fit the area in which you would like to print. The default values are set to probe the maximum size of the printing area on the AON-M2 High Temperature Build Plate, in an 8 x 8 grid. If you are printing a smaller part, you may wish to probe a smaller area with fewer grid points.

Instructions on probing a mesh and setting custom probing bounds can be found in the Calibration section under Z Calibration.

Last modified: March 9, 2020