Printer Model: Voxelab Aries Mod
MCU / Printerboard: BTT Mini E3V3 klippy.log (6.9 MB)
E3V3 klippy.log
Describe your issue: Bed dropping after print completion
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When the print completes, klipper lowers the bed around half way then kills the z motor. This causes the bed to drop to the bottom. Once the bed is at the bottom and a homing operation is performed, it drives the bed down before it starts going up even though the sensor shows it in the down position. How do I fix either of these two issues?
Since you can’t fix gravity, the common way to handle the bed dropping is by replacing the Z-leadscrew(s) with lower pitch ones, i.e. replacing T8x8 with T8x4 or even T8x2. The thread is then flat enough to prevent the bed from sliding down by itself.
Other than that, where it puts the bed after a print is defined in either your slicer’s end gcode, or your print_end/end_print macro.
Essentially, you have created a design that will give you issues on the one or the other end. A printer whose bed is dropping when motor power is cut has a design flaw.
With homing_override or force_move you could define an upwards movement before any homing operation.
BUT
this might bring you into trouble when the printer should for any reason have a different bed position and moving upwards might cause a collision.
I would claim the design if it were mine. A bad design has to be better then none I suppose. What keeps the bed slingers from having this issue? Is the print head not heavy enough to create the downward pull to cause it to slide down the screw? Is there no way to tell Klipper “if the endstop sensor is on (flag is tripping it) then do not drive the bed down”