I had an issue with a failed print where the printer was able to detect the failure and stopped the print. The failure was related to an extrusion detection. I chose to stop the print process to clean the plate. My expectation was that the printer would initiate a Homing sequence when I pressed ‘Stop’. But basically it just stopped where it left. I then tried to press the ‘Home’ button in Bambu Studio. The printer responded by leaving the build plate raised and the print head in the middle of the build plate.
I did not find a way to make a real homing, I mean lowering the plate all the way down and positioning the print head i the parking position.
You really do not want a homing sequence to happen with anything on the plate. The homing sequence is used to find the stepper positions at known X, Y, and Z coordinates. On my X1C, it moves the tool head from wherever it is to the front right corner until the steppers sense resistance and know they have reached x=255 and Y=0. Then the tool head centers itself at 128,128, and Z=0 is located by tapping the nozzle with the plate. After the limits are found, the plate is lowered sufficiently to change the empty plate. The printer is always “homed” as long as it has current stepper values for the limit positions. The bed does not automatically drop to the very bottom because this is quite time-consuming, both when dropping and when starting a new print.
Performing a homing sequence with a print still on the plate would cause the nozzle to collide with the print. The Stop sequence does not move the tool head; it only lowers the bed enough to remove the plate. The printer does not know why the “Stop” occurred; moving the tool head might make the problem worse.
So after a Stop sequence and removal of a faulty print, the only way to ‘park’ the nozzle and lower the plate to the buttom, is to either do it manually, load a new print or power cycle the printer. Is that correct understood?
Power cycling my X1C does not move the tool head or bed, and I don’t know of a “park” position. The homing sequence happens at the beginning of every print as part of the Machine start G-code (G28). Starting the homing sequence manually leaves nozzle centered, about 15 mm above the plate.
The only time my heat bed reaches the bottom is when I manually lower it to lube the Z-screws. It might reach the bottom after completing a very tall print, when the Machine end G-code lowers the bed a little and moves the nozzle near the left rear.
G1 Z{max_layer_z + 0.5} F900 ; lower z a little
G1 X65 Y245 F12000 ; move to safe pos
I think I have confused myself and others by my definition of ‘the bottom’. You are right, the plate does NOT go all the way to the bottom, it stops ~1/3 from the bottom. Attached picture is where the printer stops after a finished print, and this is the position that I thought the ‘Stop’ would reach. After the failed print I could not find a way to come back to this position. My understanding is know that only a power cycle will do it, there is no ‘magic’ botton that do that.
That position is reached by the slice and Machine-end-gcode. Hitting “Stop” will just do what it says.
However, while stopped/paused, you can use the manual controls on the display at your hearts content to make movements. When resuming the print, it’ll continue with the next line of gcode, recovering its position. Just make sure the bed is lower or at the same height as when you paused the print to eliminate the chance of toolhead collisions.
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