Hi all
I am having a really bad problem that I just can’t seem to fix. My printer used to print really good quality but recently started producing terrible z layer quality. It started doing this half way though a project I was working on. I did not change anything on the printer or any slicer settings it just started on one print and has never gone away. I thought it was a bent lead screw so I bought two new ones and replaced them but this did not change a thing. I have tried everything I can think of.
Stepper motor voltage
slicer settings I usually use matter control but I have tried cura also with the same results.
different hottend temps
different filament
and many other things
This printer is a folgertech prusa i3 2020 I have done a lot of upgrades on it.
Leadscrew upgrade
z stepper motor extenssion brackets
wade’s extruder bowden mod
hexigon hottend upgrade
autoleveling
Here are some pictures of a test print and my printer.
Any advice would be really helpful!
I’ve had that happen with filament with inconsistent diameter.
Z wobble typical follows a typical pattern, usually the pitch of the leadscrew.
Also, don’t use springs for tensioning the belt. In fast movements the spring will open up causing backlash. This type is much better: https://www.thingiverse.com/thing:16449
Looks like something is loose in XY, rather than a Z axis problem. Grab the nozzle (cold!) and wiggle it. Is the mount loose? Cracked parts anywhere? Loose screws?
@Ryan_Carlyle I have checked all that and everything seems good and tight.
Try some backlash test prints to verify. Have you measured your filament in a bunch of places with calipers? Is your drive gear jammed up with filament debris? Any binding if you move the motion stages around by hand?
@Ryan_Carlyle I have checked all of that other than the backlash test print thing. Any recommended prints to do for that test?
just printed this. https://www.thingiverse.com/thing:2256550/#files
It is odd how the lines are so regular. really seems like it is a lead screw issue but I replaced them and I have double checked that they are straight and attached properly.
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That does look like a lead screw issue. Does the ribbing match the screw pitch?
Do you have the bottom end of the screws free or constrained?
Are the flex couplers pulled tight? They can act like springs if the Z rods are binding at all.
@Ryan_Carlyle missing/deleted image from Google+
@Ryan_Carlyle missing/deleted image from Google+
@Ryan_Carlyle missing/deleted image from Google+
@Ryan_Carlyle missing/deleted image from Google+
@Ryan_Carlyle not sure what you mean but does the ribbing match the screw pitch but one of these pictures might help answer that.
The bottom end of the screw is free.
The couplers are mounted in such a way that they can not move.
Ok, your issue is NOT screw wobble. That’s one thing ruled out.
Is that a bearing or something below the screw couplers to take the screw thrust load? That will pretty much rule out coupler flex.
A ripple that repeats regularly in Z might be nozzle temperature oscillation or heatbed flexing as it cycles on/off. Could also be some issue with your drive hob like half the teeth being full of filament dust, so the extrusion flow rate is varying.
@Ryan_Carlyle Yes it is a bearing under the coupler. I have tried different nozzle temps with no success. The teeth in the drive gear are pretty clean and I am getting consistent extrusion
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@Ryan_Carlyle I will try a test print with the bed off since I should be able to do that as I have a sheet of pei on it.
@Ryan_Carlyle Really happy because that was it. Lowers look better than ever now. Thanks so much I would have never thought of that.
@Ryan_Carlyle just need to find a better way to put the pei on the bed
Can you switch to PID instead of bang-bang?
3m adhesive sheet works well.