Z wobble vs flow vs slicing

[rimbo 0]

Aim: Please help me home in on the culprit causing waviness of the side walls

Cura 5.6.x / Cura 5.7.x (currently)
My printer is a smoothieware LUME+
https://lumeplus.wixsite.com/lume/produkty

In February this year I refurbished my bootleg printer and got amazing results. I calibrated eeeeverything... Ot one point some heavy irregularities started appearing. Analyzing my photos I can see that the problem comes in and out. Recently it's all I'm getting unfortunatelly! Take a look at the Squid model and the Ultimaker bot. Those are perfect for a printer worth probably less than $100.

But there's a glimmer of hope. I noticed some of my test pieces today came out without those irregularities!

 

Note: The green knob has been printed with an extreme layer >height< of around 1.25*nozzle0.4
 

INITIAL knob or that - left console Bc knobs and holders projekt 2c the big knob Ironing ON - Copy.3mf INITIAL knob this - left console Bc knobs and holders projekt 2b the big knob Ironing ON - Copy.3mf

Z-wobble_test_Duplicator_7_DLP projekt 2 z knob F-5 Radar projekt.3mf

Edited May 16 by rimbo

[rimbo 0]

Final evening trial, I think, shows that's not Z wobble at least and that barely decent surface is still achievable on this printer...

Project file based on clean Cura default Draft profile, then  top layer removed, Wall line count 1, infill removed.

 

(E steps 180 ; changing to calibrated ~185 again tomorrow)

 

One of the initial knobs on the left for comparison.

Zwob knob F-5 Radar projekt 01 16-05-2024 evening.3mf

 

EDIT:

Also Z wobble test towers with banding that has barely anything to do with Z wobble. Also Flow Rate % in cura from 100 to 120 showed no discernable differences.

 

Further, RAW G-CODE test cubes shipped with the printer from factory. The semi-transparent one is almost 1 year old. The gray one is from today. While the seam is massive and I don't remember whether I used E steps 180 or 195, the walls are very nice, with no trace of wobble influence.

 

kostkaNowaLUME.gcode

Edited May 16 by rimbo

[rimbo 0]

I've identified two main contributors:

1.

I had Wall line width 0.5 leftover from my previous 0.4 Layer height prints. Having Layer Height at 0.2 now the WLW 0.5 made the ratio over 200%.

2.

With extruder spring very lightly tensioned and a sloppy spool sleeve the extruder had to pull on the filament cyclically which is mist probably what you see as big waves on the outer wall.

Photo shows before and after samples

[Slashee_the_Cow 382]

4 hours ago, rimbo said:

I had Wall line width 0.5 leftover from my previous 0.4 Layer height prints. Having Layer Height at 0.2 now the WLW 0.5 made the ratio over 200%.

It's not really about the ratio, you just need to make sure you're running an appropriate layer height and line width for your nozzle.

 

Layer height should never be over 80% of the nozzle diameter, so if you have the fairly common 0.4mm nozzle that would mean don't set your layer height above 0.32mm. There's no hard minimum, but the shorter you go the more precise you printer needs to be with its movements and extrusions which is why it's better to use a smaller nozzle (where such precision isn't as important because you're not trying to control a small flow through a big hole).

 

Line width should be 60-150% of the nozzle diameter (so 0.24mm-0.6mm on a 0.4mm nozzle). Too narrow and you just can't extrude or place it accurately. Too wide and you just can't get it to spread wide enough out of the nozzle.

 

Also: you're getting elephant's foot (it's squished down a bit at the bottom and has expanded sideways). Try setting Walls > Initial Layer Horizontal Expansion to -2mm or so (you can do tests to fine tune it).

[rimbo 0]

On 5/22/2024 at 2:15 AM, Slashee_the_Cow said:

It's not really about the ratio, you just need to make sure you're running an appropriate layer height and line width for your nozzle.

 

Layer height should never be over 80% of the nozzle diameter, so if you have the fairly common 0.4mm nozzle that would mean don't set your layer height above 0.32mm. There's no hard minimum, but the shorter you go the more precise you printer needs to be with its movements and extrusions which is why it's better to use a smaller nozzle (where such precision isn't as important because you're not trying to control a small flow through a big hole).

 

Line width should be 60-150% of the nozzle diameter (so 0.24mm-0.6mm on a 0.4mm nozzle). Too narrow and you just can't extrude or place it accurately. Too wide and you just can't get it to spread wide enough out of the nozzle.

 

Also: you're getting elephant's foot (it's squished down a bit at the bottom and has expanded sideways). Try setting Walls > Initial Layer Horizontal Expansion to -2mm or so (you can do tests to fine tune it).

Thanks for the info. Some of that I knew and, I don't know, lost it maybe, in the process of the hardware troubleshooting madness I have been through.

 

With the Initial Layer Horizontal Expansion I'm pretty sure you meant -0.2mm, rather than -2mm.

 

All that said I'm still not satisfied with the external surface quality.

Edited May 31 by rimbo