After fitting the free early bird extras to my P1P I thought I would run the calibration again via the printer control pad.
I did a calibration, then realized I didn’t have the plate on, so when the 1st calibration was finished, without touching anything , I attached the plate and immediately started another calibration.
It made a horrible noise as though something was trying to move but was restricted.
Could it have been the Z axis trying to raise the bed, even tho it was already at the top?
Since then, I have noticed that some of my prints are showing slight vertical ripples and I’m wondering if using the calibration straight after having already done one, may have damaged something.
The loud noise was likely a stepper motor turning without being able to because the printer thought the bed was closer than it was. So yes its exactly what you thought.
The calibration will have fixed that issue.
I doubt it would have done any damage to your prints although I guess there is a slight chance the nozzle could get damaged? The ripples you are now seeing are perhaps just your imagination and they were always there?
I sent some feedback to Bambulab that maybe they should end the calibration with a “home” so idiots like me don’t risk harm by running it a second time.
I’m hoping the ripples are related to the polygons of the object. They are not related to the infill. Perhaps I need to subdivide and smooth the object further. That would mean that the printer is even more accurate than I thought. (which makes me feel better)
alas, I’m getting some ringing on single face surfaces. I’m convinced it’s the belt tooths. I used to have it on my $180 printer. Perhaps I’m expecting too much of the P1P
You’re not an idiot. It’s a bug, that they know about, that they haven’t fixed. If you start a calibration after a home, or any other activity that leaves the bed too close to the top of bottom, the bed will crash and the printer doesn’t even know it.
there is are multiple instances where they lower the motor current for no appearant reason in the machine start code
but there is a comment in the machine end code, that says “lower z motor current to reduce impact if there is something in the bottom” - and the the very end, it reduces to motor current to 45 % and then does nothing anymore
this might have something to do with the instance, that there is probably no proper resistance turn off or limit switch for the bed
Bambulab printer does not require end stops, it use a different technic globally : it use force required by motors (a fast intensity increase) as a sensorless endstops and eventually to detect objects.
This is a great technic used by other printers and more precise (it just require to use motor drivers that handle this functionality like TMC2209).
But to avoid the issue raised in the OP, and the risk of unnecessary stress on the z motor and belt, I suggest that the calibration routine should monitor the z motor load when it raises the bed at the start of the calibration, either that, or add one line of code to do a “home” first. I have written to BL with this suggestion.
