"Load Filament" Auto-lift Error
There is a feature in the new firmware that I believe has a bug. To make loading filament easier, the firmware raises the Z-axis if it is too low when you tell it you want it to load new filament. (Not sure what the minimum height is that causes it to do that.) The bug appears to be that it doesn't correctly check the current height on the Z-Axis prior to raising it.
I discovered this bug because I have custom gcode that lifts the Z-Axis to 200mm and pushes out the Y-Axis once a print is complete. In general, this works perfectly for my needs and makes it easy to remove prints and load new filament later on. Last time I loaded filament, it raised the Z-Axis from 200 to the very top at 210 even though it really had absolutely no reason to do so.
Re: "Load Filament" Auto-lift Error
If you had printed up to 200, it raised it as far as it could. That sounds like the correct behavior. "Raise above current level (assuming a print is underway), stopping below maximum as needed." Did the change trigger at the start of a print or at the end of the one that raised it?
[...] Last time I loaded filament, it raised the Z-Axis from 200 to the very top at 210 even though it really had absolutely no reason to do so.
Re: "Load Filament" Auto-lift Error
The prior print was about 60mm tall. The custom gcode always moves it to 200mm at the end. The firmware improvement reads:
Load filament improvement:
Load filament sequence now contains movement in Z axis if current Z coordinate is lower then 20mm when loading filament starts. This will ensure that there is always enough space for cleaning the nozzle.
So I amend my previous statement about not knowing the height where it does this, since I now know the cutoff is supposed to be 20mm. The bug is that it still happened at 200mm when I selected to load filament for another print.
Re: "Load Filament" Auto-lift Error
Ah, I hadn't caught the "if below 20mm" bit before. I thought the correct behavior was to raise above current printing position. Not sure then. If you don't raise to 200 and it triggers a change, does it raise up?
Re: "Load Filament" Auto-lift Error
Yeah, after a bit of testing, it appears to raise by a bit regardless of where it stops. This is definitely a bug since it's not supposed to do that unless the Z-Axis stopped at or below 20mm.
Re: "Load Filament" Auto-lift Error
Did you have the printer off or reset it before loading the filament? If you did then it will think Z=0, even if you had it at 200mm.
Re: "Load Filament" Auto-lift Error
I don't leave my printer on unless I'm working on a print, so yes, I definitely often have it off before I load filament. That definitely explains the situation where it lifts even though it doesn't need to. I've been known to use a reset/power cycle specifically to reset where the printer things all the axes are (so I wouldn't want to not be able to do that anymore). Hmmm....
Perhaps since we are talking about the MK3 and the system is capable of remembering where it was to automatically resume in the case of a power failure, it seems like that feature may be used to record where it thinks the Z axis was last. At least until re-homing prior to a print anyway. Not sure. I guess I'm not that bothered by this happening, but it does mean I can't "finish" my print higher than Z=200 so this feature doesn't cram the Z axis into the stops at the top.
Thanks for the info either way.