Auto Bed Levelling Glitches

[Roxy]

Thanks Roxy, like always I really appreciate your help! The new marlin_main compiled fine against my existing firmware. Manually running G28 like before homes the x and y and then repositions at the middle of the bed to home the z. Subsequent G28's do the same. G29 then probes from the beginning of the bed and then returns the probe once done.

The G29 should leave the probe over the last point measured. If you do the G28 and G29 by hand you will know if that is what happens.

You have:

#define Z_SAFE_HOMING

Enabled, so the G28 will move to where ever you specified (some where near the center of the bed) to make its measurement.

I was a bit excited, and loaded up a test cube and sliced it and clicked print after that G29. low and behold it crashed the y axis, which after crashing proceeded to extrude at the same offset distance. I chalked it up to me being a dummy and not putting the g28 and G29 code into my start gcode.

My existing start code looks like so:
...

For most people, the G28 should be followed immediately by the G29. There may be a reason to do something different. But in general, most people do a G28 and then a G29.

Would I also have to then adjust anything else in slic3r or otherwise then? I was a bit worried with effectively having the print head starting from the middle of the bed, which caused the Y crash, but it could be just cause I never had g28 and g29 in my start code...

I suggest you do what ever startup GCode you want to put into your slicer by hand, one command at a time. Do a G28 and then a G29. And then a M114 to see if it is at the location that look reasonable given where the probe is. If it is... You should be ok telling it to start a print. It is troublesome that it crashed your Y Axis. But if you do these three commands by hand, we will know a lot more about what is going on.

I just wanted to say thank you again too, especially for some of my dumb questions. I've admittedly been rushed with so many projects on the go, that I've probably over looked things I shouldn't have!

This stuff is really hard. And it is a shame to wreck all the hard work it takes to get a printer going just because nobody is there to answer 'simple' questions. Its only simple after you have been through it a few times.