Semi-Automatic Bed Leveling

If you have a digital bed leveling sensor like the BLTouch on your 3D printer, you can use it to manually level your bed to near perfect, and leave the sensor to pick up any remaining slack during your prints. The following instructions are for Marlin firmware.

  1. Set the bed temperature to your usual print setting, using M190. For example, M190 S50
  2. Use G28 to auto-home. This ensures the print head is where the printer thinks it is.
  3. Start auto bed leveling with G29. This will return a matrix of measurements in the console.
  4. Review the measurements. You want each to be as close to 0 as possible.
  5. Level your bed manually by making small adjustments and running G29 again to check on progress. Remember that every adjustment you make affects the entire bed, not just that corner.

If you’re finding your bed isn’t perfect, because of the middle values, even though your corners are level, your bed may be warped. This is often caused by the 4 point leveling system forcing the points closer together than the bed would like, so it’s also worth looking into 3-point leveling solutions – expect to pay about $15 on AliExpress.

If you’re comfortable writing GCode scripts, you could use G30 to manually probe each point exactly above your leveling screws,