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Inconsistent Z ribbing/banding

Posted by eviltoy 
Inconsistent Z ribbing/banding
August 30, 2016 03:29AM
So I recently built a Wilson 2 running a e3d v6 and titan extruder. I have been get very inconsistent banding across all prints. All steps are correctly configured and the extrusion is accurate but the layers do not seem to be uniform at all. Any ideas what it could be? All belts are tight and the z axis moves freely



Re: Inconsistent Z ribbing/banding
August 30, 2016 09:26AM
Play with your retraction settings. I had this issue on a CoreXY when I switched to a geared extruder. As I started adjusting my retraction settings, the banding disappeared and the print quality went up.
Re: Inconsistent Z ribbing/banding
August 30, 2016 09:59AM
Try a print with your heated bed turned off, that looks like bed flex.
Re: Inconsistent Z ribbing/banding
August 30, 2016 03:52PM
Will try both suggestions and report back
Re: Inconsistent Z ribbing/banding
August 30, 2016 07:34PM
I'm getting the same but in reverse.

Every so often the Z goes too far. Or the extrusion is low. Not sure which. Well at least thats what I thought it was. Now I'm not so sure..
I have all steppers calibrated to about 0.025%. Might be out by a less than 10 microns over 100mm. Hard to tell.

I was going to start a new thread, but this one looks like a similar issue.

The cube and the creeper in this pic where printed with identical settings and slice. Except slightly higher ext temp on the cube. Now I'm thinking filament variation....


Here are some closer pics of the cube. I have many cubes like this, Changing extrude temp and flow rate doesn't make it change.
Changing Z steps or layer height will change the banding pattern.
Octocat offered a good clue. The anorexic layers are extra defined on the underhand, like the top on the nose, but its not visible on the overhang like under the cats chin.







I think I may have a missed step issue on z, The left and right screws get out of sync sometimes. But this looks like extra steps rather than missed steps.... And the out of sync thing seems to only happen at startup and may be mecanical (looking into it more today)

The black cube was a different nozzle (1mm) etc. But it still happens more randomly sometimes with that setup. Its driving me completely bonkers for the last 2-3 weeks.... I keep messing with zstep/layer height because it looks like a non divisible layer height thing. But I Feel like I should have gotten at least closer to fixing it by now.

Something that may or may not be related. I set slicer to do infill every 4 but its not, its doing it every layer. The cube measures 200 microns too wide on xy and 120 microns to short on z.

Edited 1 time(s). Last edit at 08/30/2016 07:38PM by Mongrel_Shark.
Re: Inconsistent Z ribbing/banding
August 30, 2016 11:46PM
Update.

I think my problem was non-print acceleration. Likely unrelated to the ops problem.

I set firmware non-print x-y-z accel from 300 to 30. Still waiting on the first cube, but its into the inset letters and no bad layers.
Its one of the best prints I have done! X&Y are ridiculiously slow in non print now, but it works. I think I can balance speed against detail now I know what it is.

If anyone knows a good thread already discussing this PM me a link. I'll stop hijacking this thread now grinning smiley
Re: Inconsistent Z ribbing/banding
August 31, 2016 02:31PM
Ok played with retracts even turned them off same issue
Re: Inconsistent Z ribbing/banding
August 31, 2016 02:46PM
What is your extrusion steps/mm set to for the titan? Was it calculated on trials or via equation? If you did it via equation, did you measure the diameter of the hobbed section of the titan extruder?
Re: Inconsistent Z ribbing/banding
August 31, 2016 03:43PM
I measured distance extruded and calculated its on 419 in the firmware and extrudes exactly 100mm when requested
Re: Inconsistent Z ribbing/banding
August 31, 2016 03:46PM
I removed the threaded rods and realigned and regreased to no avail its extremely inconsistent
Re: Inconsistent Z ribbing/banding
August 31, 2016 04:00PM
Have you tried printing slower and see if its not related to speeds?
Re: Inconsistent Z ribbing/banding
August 31, 2016 04:01PM
Yes i have started At 50mm/s and down to 30mm/s still the same
Re: Inconsistent Z ribbing/banding
August 31, 2016 04:09PM
Just to cover the bases, try it at 10 or 15 and see if it is still there.
Re: Inconsistent Z ribbing/banding
August 31, 2016 04:10PM
Ok will give it a shot
Re: Inconsistent Z ribbing/banding
August 31, 2016 05:40PM
I have 7 spools of 1kg pla, 2 purple, 1 pink, 1 red, 1 black, 1 blue and 1 white

the white was the worst and the blue is like yours, the rest were perfect, all using same print settings, only print speed below 30mm/s will show improvements,

it didn't even matter what hotend I use, I have both genuine e3d hotends and chinese knock off, have you tried any other filaments?

I was even able to print with the red at 10 micron no problem either with genuine e3d or chinese knock off, both gave same results

Edited 1 time(s). Last edit at 08/31/2016 05:40PM by deaconfrost.
Re: Inconsistent Z ribbing/banding
September 01, 2016 01:29AM
I tried petg in white and it was the same ill try slowing it down when i get home
Re: Inconsistent Z ribbing/banding
September 01, 2016 09:14AM
try printing without bed heat.......seriously. I've been printing for 4 years, I might know something.......

Edited 1 time(s). Last edit at 09/01/2016 09:15AM by Dirty Steve.
Re: Inconsistent Z ribbing/banding
September 01, 2016 09:17AM
Quote
Dirty Steve
try printing without bed heat.......seriously. I've been printing for 4 years, I might know something.......

I only have abs at the moment. Ill try it soon as I get home though with some glue stick. The bed is tuned though and temps dont deviate but will still try it
Re: Inconsistent Z ribbing/banding
September 01, 2016 09:41AM
heat bed does have a big effect on print quality, I have stopped using heatbed for the last 3 months

I print pla on acrylic plate and abs juice on the plate with no heat bed, all good

I see a quality improvement especially on lower layers

Edited 1 time(s). Last edit at 09/01/2016 09:41AM by deaconfrost.
Re: Inconsistent Z ribbing/banding
September 01, 2016 09:42AM
Quote
deaconfrost
heat bed does have a big effect on print quality, I have stopped using heatbed for the last 3 months

I print pla on acrylic plate and abs juice on the plate with no heat bed, all good

I see a quality improvement especially on lower layers

Pla is a no go for me as most of the parts I print will be subjected to some heat stress and machining at some point
Re: Inconsistent Z ribbing/banding
September 01, 2016 09:45AM
try using abs juice and turn off the bed, not sure if it matters on other build plate material but it works well for me on acrylic plate
Re: Inconsistent Z ribbing/banding
September 01, 2016 09:46AM
Ill try that when I get home. I print on kapton with abs juice
Re: Inconsistent Z ribbing/banding
September 01, 2016 09:53AM
For ABS, slice with a brim, use glue stick or hairspray. It's not the tuning of the bed heat, alot beds can flex with a 1 degree heat swing, and that is only at the thermistor, not the entire surface/mass of the bed.
Re: Inconsistent Z ribbing/banding
September 01, 2016 01:43PM
ok tried temp lowering of the bed. Printing at a higher temp. And slowing it down now with the same results. At a loss now
Re: Inconsistent Z ribbing/banding
September 01, 2016 01:45PM
oh and no heated bed too
Re: Inconsistent Z ribbing/banding
September 02, 2016 04:05AM
Realigned the belts and tensioned them again. Also checked stepper positioning. Changed nozzles as well. The irregularities continue. Ill be getting some new belts and leadscrews today and also changing to silent stepsticks for x and Y
Re: Inconsistent Z ribbing/banding
September 03, 2016 02:20AM
Found flex in the extruder mount but alas it was not the silver bullet
Re: Inconsistent Z ribbing/banding
September 03, 2016 08:19AM
Changed leadscrews same issue
Re: Inconsistent Z ribbing/banding
September 04, 2016 02:51PM
So i realigned the z motors and then tightened the extruder idler. Now i have a semblance of consistency in the form of ribbing
Attachments:
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Re: Inconsistent Z ribbing/banding
September 06, 2016 03:56AM
how firm is your frame and z rods?

I just finished a new build of a large printer using full leadscrew on all axis, made sure the frame is fully rigid and all rods are firm, layer consistency is 110% from first print

Edited 1 time(s). Last edit at 09/06/2016 03:56AM by deaconfrost.
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