Z axis lead screw makes terrible noise and vibrates when lowering

jgmakerguy

A have a JG Aurora A5. A couple years ago, the hot end crashed into the print surface hard, for no apparent reason, destroying the fan duct. I didn't repair it for a couple years, at which point I could not lower it on the z axis -- the motor turned but it just bound up. I sprayed the lead screws generously with lubricant and eventually got it to work. After printing an improved "blowhard" fan duct to replace the destroyed one, replacing the blower fan which had also failed, disconnecting the filament sensor which constantly falsed, and spending a lot of time bed leveling, it is now printing better than ever.

However....it now makes a terrible noise when lowering the Z axis, and the right lead screw vibrates and wobbles (see this video). It doesn't seem to affect printing, but it definitely seems like something that needs to be fixed.

Any ideas on what exactly might be wrong and/or how to repair?

michalko99

lead screw shall not be sprayed, but lubricated by some grease. Oils has very low viscosity. apply grease and try to spread by moving axis up and down. Also Z axis movement is too fast for my taste. Are you using pronterface for this video or is it default movement speed?

jgmakerguy

Thanks I'll try grease. The z axis speed in the video is from the printer's front panel. but even if I use the lowest speed (I believe 0.1mm) I still get the noise and vibration.

Assuming the grease improves it, would you say this noise/vibration is "normal" as opposed to a sign of damage, misalignment, etc?

michalko99

have you done some modifications on printer?Any mod can be a key...

jgmakerguy

No mods other than upgraded fan duct...

jgmakerguy

Thanks, a liberal slathering with lithium grease got rid of 80% of the noise/vibration!

michalko99

it will get better in time. Just use printer more frequently. Good that it helped