I’ve been observing for a few days now and again that the print head moves into a corner and then wants to continue. It rattles extremely loud.
The printing bed also sometimes wants to go further down, although the bed is already all the way down. That can’t be right, can it?
Does anybody else have this problem?
Can you take a video?
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In this case i would start the Calibration first. Therefore bring the bed in middle position, at least 50mm under the upper end manually.
!!!If the bed is too much at the top you could breake your nozzle!!!
One time my bed position was nearly at the lower end. I startet calibration and the bed went further down and did not stop and there was the „loud“ rattling sound from the pulleys/belt.
So when i start a print or calibration i‘m checking not to be at the lower or upper end with z-Achsis
I always home the printer before starting a new print
This goes back long before Bambu Lab was even established that with my other printers sometimes if I didn’t home the print head and bed first things would go South real quick
I reckon after a print you tried starting a new print before everything was in the home position
Then again I could be wrong and you may have a different issue, but not homing the printer first is how it reads to me 
I agree. My old Black Widow won’t let me do anything until it has ‘homed all’ which for the most part is a good practise.
Today i had it the first time. started a print after the bed was very low. when it went down it did this rattling sound from sitting with the bed on the ground.
i think that is not so good for the belt if happens to often.
i´m thinking maybe we can put in a line in the machine-gcode at the beginning to perform a homing before
There are lots of similar problems I’ve reported to support, it would be helpful if everyone opens tickets who sees any of these issues.
Some of the things I’ve noticed:
1.) Perform “home” procedure - at the end, bed will be left near the top of z axis.
2.) Perform “calibration” procedure - at the beginning, calibration moves bed up a number of stops. Despite the home procedure just being performed, the bed moves up by a pre-programmed amount, colliding with the print head, potentially causing damage to the bed, and grinding the z stepper motor.
1.) Have print bed near the bottom, start a print
2.) Print bed will collide with bottom of printer, causing grinding on the z stepper motor.
Also, in the case of changing toolhead:
1.) Perform “Home” procedure, then power off printer to change toolhead.
2.) Power on printer, perform a home or calibration immediately after power on, bed smashes into toolhead.
Basically, home, calibration, and print procedure all perform an initial move that is unaware of the bed z position and causes grinding if the bed isn’t in the right place.
The bed has piezo sensors, for some reason they are not used during the initial movement procedure and the bed doesn’t detect resistance.
Same issue here ever since I got the P1P a month ago
If it starts a print with the bed near the bottom it initially tries to move the bed down further and grinds the z stepper motor