Woops, what happens with my printer?

[DIY3D]

Hi,

My MakergearM2 printer has not been used for a few months and now shows strange behavior. The heated bed doesn't go up to its homing position. If the heated bed is is at his highest position, it goes down to the middle position and start printing.

Can anyone explain what is wrong and how this happened?

https://youtu.be/szeaAG2Wnt8

Kind Regards,
Marco

[ednisley]

not been used for a few months

Aaaand is in need of routine maintenance.

Clean all the sticky gunk and fuzz off the Z-axis leadscrew & guide rods, then lube per the instructions. Make sure you can turn the Z-axis leadscrew by hand with the same effort from top to bottom and back again; if it's noticeably harder at one end, then the guide rods may need realignment / attention.

After doing that, verify the Z-axis limit switch works correctly by jogging the extruder off to the right of the platform, then homing the Z-axis. If it doesn't home-and-stop in the correct position, figure out why.

in a situation like this, it's safe to assume something mechanical is bent / out of alignment / full of crud, rather than jumping to the conclusion it's a firmware / software problem.

[DIY3D]

Dear Ed,

Thank you for your support,

I expected it to be the stepper motor, but I'll start with a thorough cleaning ... I have work to do

Just can't explain what that weird sound is?

Kind regards,
Marco

[Gwhite]

Check out this thread: viewtopic.php?f=7&t=5453&p=42313#p32627

[DIY3D]

Yes, fortunately, a good cleaning was enough.

For cleaning the Z-axis I used Isopropyl Alcohol and a toothbrush and wooden tooth pickers. I don't like the grease for the Z axis. I have used light synthetic oil for all axis.

https://youtu.be/LvsammgGDhg

I have to admit, I bought this printer in 2013 .... and I can't remember when I cleaned the XYZ axes

Thanks guys!

Kind regards,
Marco

[ednisley]

can't remember when I cleaned the XYZ axes

None of us can, because the only time we clean things is when they stop working … [sigh]

what that weird sound is

That's what a stepper motor sounds like when the rotor has lost sync with the driving pulses. It doesn't do any damage, it just serves as a clear indication the motor is overloaded and can't provide enough torque.

Everybody immediately jumps to the conclusion the printer suddenly has a software or firmware problem (and immediately begins randomly changing things), because nobody realizes how gummy a leadscrew can get after a few years in open air.

Now that you've heard it, you'll know what to do the next time!

[Gwhite]

One of the things I've found on the rare occasions that I remember to clean my Z-axis lead screw is a ball of super fine fuzz at the top of the screw. This is basically almost invisible stringing that is occurring during large moves that has gotten blown around by the fans and has found its way onto the lead screw. A tiny film of oil on the screw helps it stick, and then it all gets jammed up at the top at the printer operates. It's particularly bad with PETG because that tends to string more than most PLA.

I like to have the build plate drop down & move forward at the end of a print so it's easy to remove the model, but if you do that while the extruder is still hot, it tends to create really long strings that make the hairball problem worse. I modified my ending script a while back to drop the model slightly, and then wait for the hot-end to cool down before I lower the bed the rest of the way. This has helped reduce the fuzz on the lead screw considerably, and I can go a lot longer between cleanings.

The ending script I'm using is as follows:

G92 E0 ; Set extruder to zero
G1 E-15 F3000 ; Retract 15 mm of filament
M140 S0 ; turn off bed
G91 ; relative mode
G1 Z10 ; lift 10mm
M109 R48 ; Wait for hotend to cool to 48C
M104 S0 ; turn off extruder
G90 ; absolute mode
G1 Z180 ; drop Z axis for easy removal
G28 X0 ; home X axis
M84 ; disable motors
M106 S0 ; Stop bed fan