Mini+ Z Axis Issue When Parking
This has happened to me twice now. I've had my printer since about January. I did the full assembly myself and it worked great. Recently, when I change the filament, the z height will say it's parking and then try to go above the z axis height and it will make a grinding noise. Does anyone know why it would do this? Does it need recalibration?
Thank you!
RE: Mini+ Z Axis Issue When Parking
When you turn the printer off an on again, it doesn't know at what Z position it is (you could have moved the extruder up and down manually while it was turned off). So to be safe, it always moves the extruder up a bit before a filament load. If the extruder was at a high Z position at the end of the last print, this may result in the printer hitting the top of the Z-axis, resulting in the noise. This is normal behavior and no cause for concern.
RE: Mini+ Z Axis Issue When Parking
I was noticing the same behavior with Mini+ too when loading or unloading the filament.
Sometimes the Z axis is already 3/4 up the max and the parking routine when loading or unloading filament occasionally tried to continue going up the Z axis and hitting the maximum and making a grinding noise.
Thank you for answering the issue.
I hope maybe this issue might be resolved in a future firmware update so that the printer knows when to stop the Z axis from going any further
RE: Mini+ Z Axis Issue When Parking
I don't know if this is part of the issue, the printer doesn't know where the extruder is, when it is first turned on,
It assumes the extruder is a 0.00 mm until the Z axis has been homed.
If your extruder was at the top of the Z axis, at the end of the last print, then the printer still thinks it is at 0.00mm, so any protection about rasisng too high, is likely to fail...
if you are high on Z axiz, you can always do a Home All axis, from the LCD
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Mini+ Z Axis Issue When Parking
I hope maybe this issue might be resolved in a future firmware update so that the printer knows when to stop the Z axis from going any further
Doubtful because that is exactly the desired behavior. The printer can't know where the extruder is because you may have moved it manually while it was off. The grinding noise on top is a consequence of the mechanism the printer uses to know it hits top. Not harmful.
RE:
So to be safe, it always moves the extruder up a bit before a filament load. If the extruder was at a high Z position at the end of the last print, this may result in the printer hitting the top of the Z-axis, resulting in the noise. This is normal behavior and no cause for concern.
Are you sure that this bug or the printer's inability to locate the z axis position is not resulting in permanent damage?
This basically happens after every print that ends with a certain height (which also means that the printer *DOES* know the Z position) and I fear it will damage the motor or something. The most infuriating thing is that it's not even possible to manually move the Z axis down since the printer just assumes it's already at "0" and just won't move it down, ironically probably to prevent just the kind of damage it might actually be causing.
RE: Mini+ Z Axis Issue When Parking
The most infuriating thing is that it's not even possible to manually move the Z axis down since the printer just assumes it's already at "0" and just won't move it down, ironically probably to prevent just the kind of damage it might actually be causing.
If it really concerns you (which it shouldn't), follow Joan's advice above:
if you are high on Z axiz, you can always do a Home All axis, from the LCD
RE: Mini+ Z Axis Issue When Parking
I doubt the printer “uses the noise” to know it reached the top. You can achieve the same effect by manually moving the z-axis and rapidly spinning the wheel beyond 180mm. The printer is too stupid to stop moving the stepper once it reached the max. There is no sensor for noise, increased power consumption by the stepper, or no movement in the axis. It just tries to spin the stepper until the current movement command ends.
I’d rather avoid putting that stress on the stepper and the screw. I haven’t seen that “home all axis (axes?)” command yet but used the level bed command instead to get the z axis down if it ended up too high from the previous print.
RE: Mini+ Z Axis Issue When Parking
I doubt the printer “uses the noise” to know it reached the top.
Of course not. There's no microphone or something. The noise is just a by-product of the mechanism the printer uses to find the end of the Z axis, which is the stepper drivers detecting that the Z-axis motors are stalling when the Z-axis hits the top of the gantry. Again, this is all normal (see section 6.3.6 of the 3D printing handbook). I mean, you may like the sound of it as much as chalk scratching over a blackboard but I'm not aware of any reports of it being detrimental, with over 100,000 machines in use.
RE: Mini+ Z Axis Issue When Parking
I experienced the same issue and the noise that you can hear is not pretty. This should be reported in the manual (I have the one from the semi-assembled kit). In addition I think that the sound of the z axis moving has now changed; however I ran an autotest and it passed. The few prints I have performed seemed alright, I just got a little of bending in a PLA print on a texture steel plate that never occured to me before. Are there any prints that can stress the z axis to identify wether is not moving smoothly anymore?
RE: Mini+ Z Axis Issue When Parking
I experienced the same issue and the noise that you can hear is not pretty. This should be reported in the manual (I have the one from the semi-assembled kit). In addition I think that the sound of the z axis moving has now changed; however I ran an autotest and it passed. The few prints I have performed seemed alright, I just got a little of bending in a PLA print on a texture steel plate that never occured to me before. Are there any prints that can stress the z axis to identify wether is not moving smoothly anymore?
For the record, it seems it was a false alarm. The different noise is not something I hear all the time, might have been due to something else. I also performed the incriminated print several times and results are inconsistent, sometimes I get more or less bending, sometime none (it's not an easy print, it's PLA on texture sheet with thin base on some deatails and many bridges). I will try printing it with brim.
Hope this helps
RE: Mini+ Z Axis Issue When Parking
To summarize, indeed it's not a problem and it is wanted behaviour.
However it's annoying and easily forgotten and not great for the stepper motor!
I propose a solution; a script that when finished printing asks to remove the print and when pressed ok lowers the z- axes to 15. This way its not 0, so you can easily remove the buildplate and when you change filament next time you don't need to worry about possitions. And, if you setup prusa slicer correctly it could be automatically added to every printfile, so no forgetting possible!
I will execute it when time is available and add the code. But if you are quicker, feel free to use the idea.