Welcome! Log In Create A New Profile


Cura and Dual Extruders - Firmware Offset Issues

Posted by markag 
Cura and Dual Extruders - Firmware Offset Issues
June 17, 2019 11:05AM
I built a new custom designed printer and fired it up for the first time late last week. It is a dual extrusion machine, and I've designed with extra travel in the X direction so both nozzles can reach 100% of the build surface. I also entered the nozzle offset in the marlin firmware, which seems to be leading me to have some issues using Cura.

Because the offset is set in the firmware, I have the offsets in Cura set to essentially zero (It's actually some small value to compensate for the physical tolerance difference off the nominal designed offset). Everything seems to work as intended as long as I have some functionality going to extruder #1. Single color prints, dual color prints, prints using only extruder #2 but with a skirt being printed by extruder #1. The issue I run into is if I try to print with only extruder #2 and do not have any processes going to use extruder 1.

In that configuration, doing only extruder 2 in a print, my auto bed level fails in a dangerous way. After my axis all home, I go into an auto bed level with my BL Touch sensor, but for some reason it positions the sensor too far to the left and the BL touch ends up off the left side of the bed. In the start G code, I call out a G28 to home all axis, and the next line of code is G29 to do the auto bed level. Somehow it is getting instruction to apply an offset in the negative direction based on the firmware offset on the 2nd nozzle position.

I downloaded simplify 3D to see what a different slicer would do (I had wanted to try it out anyway for my commercial projects). The same scenario of using only extruder 2 does not produce the incorrect auto bed level routine. Something about the way Cura is handling this scenario is causing this issue.

Has anyone experienced this, or have any suggestions on how to correct it?
Sorry, only registered users may post in this forum.

Click here to login