Inconsistent extrusion / Z Banding

[Roycinger]

Hi,
first and foremost I would like to bring this issue to attention where we can track it all together properly. Discord doesn't seem the right place for me as messages and focused discussions get overscrolled and interrupted with non-related topics very quickly.
Before I start I want to mention that I don't expect this issue to get solved by the Voron Team alone. Moreover, I want to evaluate this together with you so that the entire Voron community can benefit from it.

I started facing this extrusion issue when I completed my 100%-built-by-specc Switchwire. In the beginning I was thinking that the printer wasn't properly tuned yet. So I went through all the tuning steps (aligning belts, rails, tuning for filament, E-steps, run_current etc). The result didn't improve within about 90 or more test prints (where I tested every single extrusion related slicer and firmware setting).
Over the course of a few weeks, I partly reassembled the SW again, paying special attention for accuracy, squareness, etc, results didn't improve. At this point I was still under the impression that the issue was on my side as the issue still persists.
To rule out the AB, I converted my SW to bowden and the issue was gone! So I came to the conclusion that there might be a problem with the AB itself.
Because of that, I reprinted the Clockwork parts, changed the TL gears, changed all bearings, changed the motor, changed the entire hotend, precisely cut the PTFE tube. No change in results at all.
For informational purposes, this is my config: https://pastebin.com/nyULd4ca
Fast forward:
Up to yesterday, I noticed that more and more people are facing the same or similar issues, even if they might be fine with the results.
I got sent a plethora of pictures which I was allowed to use in this Git issue. They all more or less show the same problem,
Please note that most pictures where shot with "bad" light, directly from the top to make the issue apparent.
These are kinda mixed from specc-built v2.4's and SW's.



Cubes from my SW:


Random v0 part printed with my SW:

Another set of v0 parts:

For my part, I could rule out any looseness in the kinematics or topics related to filament (as I made tests with PETG, PLA and ABS from various brands).
Those defects appear either random (not at fixed heights) or depending on print features within the model (plateaus, holes, etc).

For me it comes down to a few points:

• requirement of quality is not the same for every user (they might live with the defects)
• There might be issues with either the AB internat geometry or the ABS shrinkage bothering with the tolerances
• related to the point above: A genuine Bondtech BMG in a direct drive situation in another (non Voron) printer works perfectly without showing these defects
• Using a bowden extruder (M4 in this case) eliminated the issue

Yesterday, I had a brief conversation with Ray. I introduced the topic "Prusa Issue 602", which looks awefully similar to this.
I would be happy if you could either assist with this issue or shed some light on it.

Thanks in advance!

[toskium]

Thank you for submitting this issue. I do experience the same results and I was not yet able to pin down the root cause of it.

[toskium]

To add something to the issue. I was doing input shaper calibration and the outcome of the calibration print is imho interesting.

Since klipper calculates the extruder acceleration according to the xy acceleration the striping pattern changed accordingly.

See the attached picture.

It appears more or less intense starting from acceleration 1250 all the way up to 7500.

[BladeScraper-Designs]

Same here as well. tried new BMG parts, various flow settings, various accels and speeds from 30mm/s and 500acc to 120mm/s and 5k accel, etc. Mechanics are solid and have been checked over and over for loose screws, non-smooth rails, belt tension, etc. The only thing that's left is the extruder.

V2.4 Afterburner DD
SKR 1.3 / TMC2209
StepperOnline 17HS08-1004S
Trianglelabs Dragon
Trianglelabs BMG Components

[Gizzzle]

Can confirm the issue.

[mgineer85]

Just built a v1.8 with bowden. I think I don't see the effect, which aligns to your proposal, right?

[toskium]

Just built a v1.8 with bowden. I think I don't see the effect, which aligns to your proposal, right?

Yes, correct. The issue seems to be exclusive to the clockwork extruder. Your input is much appreciated!

[Serpreme]

Can we make a list of the items that are used and not used between the bowden and direct drive? The gears, motors, wiring, and then we can slowly eliminate those items. We can try to test for things like EMI for example

[Gizzzle]

Can we make a list of the items that are used and not used between the bowden and direct drive? The gears, motors, wiring, and then we can slowly eliminate those items. We can try to test for things like EMI for example

I can eliminate every part on the Afterburner except the hotend, but that's not the problem since the other guys are using a dragon while I'm using a v6. Also EMI is not the issue since I used another motor without cable management which lead to the cable not crossing another cable in it's way to the board.
Stepper driver was also swapped from a LV8729 to a TMC2209

[BladeScraper-Designs]

Added details to my post.

[eddietheengineer]

Hello everyone, I have a recommendation to make.

In order make a proper comparison, I recommend that someone mount a BMG extruder directly to Afterburner in place of the Clockwork module. If the issue clears up, then you can root cause the issue to be something with the clockwork module itself. If the issue persists, then the source of the issue is something else.

I would not compare a bowden and direct drive mount of the same extruder--the physics of printing through a long tube with springy filament is different than when the extruder is right on top of the hotend.

[Gizzzle]

Hello everyone, I have a recommendation to make.

In order make a proper comparison, I recommend that someone mount a BMG extruder directly to Afterburner in place of the Clockwork module. If the issue clears up, then you can root cause the issue to be something with the clockwork module itself. If the issue persists, then the source of the issue is something else.

I would not compare a bowden and direct drive mount of the same extruder--the physics of printing through a long tube with springy filament is different than when the extruder is right on top of the hotend.

We had the idea too, but that's nearly impossible because of the small footprint of the afterburner.

[JayAwesome87]

Same problem since day one. I'm using a Galileo Clockwork now and the problem still persists.

[Roycinger]

In order make a proper comparison, I recommend that someone mount a BMG extruder directly to Afterburner in place of the Clockwork module. If the issue clears up, then you can root cause the issue to be something with the clockwork module itself. If the issue persists, then the source of the issue is something else.

This is easier said than done because of a few points:

• The BMG is 2.6mm thicker than the Clockwork:
  
• The filament path is not the same as the Clockwork's:
  

All in all, almost every single part of the AB would have to be redrawn to accomodate a BMG

[eddietheengineer]

Same problem since day one. I'm using a Galileo Clockwork now and the problem still persists.

Is this the version with planetary gears? If so, this would imply that it's not the Clockwork module itself but something else :) since there are no shared parts between the Galileo Clockwork (planetary) and the standard Clockwork BMG version.

Also, can we make sure to document which printer these examples are from? That would be helpful in the root cause!

[Gizzzle]

I'm using my Ender Switchwire Conversion

[eddietheengineer]

In order make a proper comparison, I recommend that someone mount a BMG extruder directly to Afterburner in place of the Clockwork module. If the issue clears up, then you can root cause the issue to be something with the clockwork module itself. If the issue persists, then the source of the issue is something else.

This is easier said than done because of a few points:

• The BMG is 2.6mm thicker than the Clockwork:
• The filament path is not the same as the Clockwork's:6bc29c552557.png)

All in all, almost every single part of the AB would have to be redrawn to accomodate a BMG

Let me see what I can do, I would like to support your testing! I do not have time right now for diagnosing the issue but I may be able to provide some parts you can print with to test the theory.

[JayAwesome87]

Same problem since day one. I'm using a Galileo Clockwork now and the problem still persists.

Is this the version with planetary gears? If so, this would imply that it's not the Clockwork module itself but something else :) since there are no shared parts between the Galileo Clockwork (planetary) and the standard Clockwork BMG version.

Also, can we make sure to document which printer these examples are from? That would be helpful in the root cause!

Yep, the one with planetary gears. Printed on a Voron 2.4 250.

[eddietheengineer]

I am thinking something simple like this--no part cooling, but it should still show if the clockwork module is the issue

[Gizzzle]

I indeed worked on a solution like this. Need to wait until my V0 is ready again to print the parts...

[eddietheengineer]

that looks good! I think it will work for testing 👍

[herexx6349]

same issue hier with a brand new 2.4 with AB

[herexx6349]

took some photos under a microscope, looks like a x/y wobble^^

[Gizzzle]

Update: Adding the complete BMG didn't make a difference. So there must be a problem in something that the Switchwire and the V1/V2 have in common.

[maximm07]

Just for my curiosity, my 2.4 voron is in final build stage so i will be able to test myself soon..is the issue appearing with all hot ends? dragon, V6 and mosquito? is it the same with any of the mods optimised for cooling (5015 variants)? current hotend cooling for dragon is not the best, for V6 it should be ok tough.

[Roycinger]

Just for my curiosity, my 2.4 voron is in final build stage so i will be able to test myself soon..is the issue appearing with all hot ends? dragon, V6 and mosquito? is it the same with any of the mods optimised for cooling (5015 variants)? current hotend cooling for dragon is not the best, for V6 it should be ok tough.

Afaik it happens across all hotends. I'm not too sure about the Mosquito as very few people are actually using it.

Update: Adding the complete BMG didn't make a difference. So there must be a problem in something that the Switchwire and the V1/V2 have in common.

Please note that a BMG Clone was used by Gizzle for the test.
In my initial post I was speaking of a genuine Bondtech BMG.

[jtrmal]

@Roycinger how about trying "git bisect"? I'm in my post-construction afterglow and I don't have a good idea how my prints should/could look like, but bisecting might help you

[Roycinger]

@jtrmal I dont see how a git bisect could help with this issue. Could you please elaborate?

[jtrmal]

hm, I was thinking if you could pinpoint some working (i.e. producing nice prints) revision and using the current as "bad", you could (perhaps) manage to track down which commit has introduced this deterioration?

[jtrmal]

but I just noticed there is an implied fact these are all new machines? In that case bisect wouldn't help, I think, yeah....

[Roycinger]

As a general plea:
If you're experiencing a similar issue, please make sure it's really related to this issue.
Though it might look similar, the root cause can be vastly different.
The issue for me and @Gizzzle was solved by converting to bowden, so we can eliminate rails as the root cause.
Rather, this strongly points to some aspect in the Afterburner

[JustinCaseOfWolf]

I am not really sure. I had to guess my length. For the ptfe

i have cut the afterbuner top in half so i can measure exactly the ptfe length. not quite the fastest / cheapest way to do it but i know for sure it is the correct lenght. so in my case that does not apply

[JustinCaseOfWolf]

@ctilley83 different colours shows different surface. while yours is less obvious than the black above i am sure with the right light your can be made more visible.

[rcfishhunt]

I am making some progress with this. And it might seem simple. The build instructions say nothing about using the nylon washer on the thumb screw from the bmg parts. I took mine off and replaced it with a thin flat washer to keep the spring from digging in to my printed parts and was able to reduce spring tension and it is making an amazing difference. Still loosening to get the best results. But her is with and without the nylon spacer

[Gizzzle]

I am making some progress with this. And it might seem simple. The build instructions say nothing about using the nylon washer on the thumb screw from the bmg parts. I took mine off and replaced it with a thin flat washer to keep the spring from digging in to my printed parts and was able to reduce spring tension and it is making an amazing difference. Still loosening to get the best results. But her is with and without the nylon spacer
Uploading 20210126_174702.jpg…

Unfortunately I can't see your pictures, but I have used the washer from the beginning and my print quality was bad. So maybe it's only a coincidence in your case.

[rcfishhunt]

Ok I will try to reload them

…

On Tue, Jan 26, 2021, 6:27 PM Gizzzle ***@***.***> wrote: I am making some progress with this. And it might seem simple. The build instructions say nothing about using the nylon washer on the thumb screw from the bmg parts. I took mine off and replaced it with a thin flat washer to keep the spring from digging in to my printed parts and was able to reduce spring tension and it is making an amazing difference. Still loosening to get the best results. But her is with and without the nylon spacer Uploading 20210126_174702.jpg… Unfortunately I can't see your pictures, but I have used the washer from the beginning and my print quality was bad. So maybe it's only a coincidence in your case. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#6 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AOGTLB5BJCL3HCDRTFDM7PLS35MWJANCNFSM4VRDNUKQ> .

[ehellman]

I have followed this discussion for a while and sadly haven't been able to chip in because I am still waiting for my POWGE package which contains all my pulleys etc.

Have printed the entire AB though, inspected, measured, tried V6 and Dragon variants. While I do have some ideas, first I would like a question answered, if anyone has time:

We see a bunch of calibration cubes here, great. But could someone take the time to create a vase mode print and post it here? Doesn't have to be a super advanced vase. I usually print a 100x30x120 (x, y, z) rectangle in vase mode to make some basic tests. Then I switch over to one of the widely available vase models, but the simplest ones are the ones that could show you the biggest effects. It should have some shapes, but not go overboard with it. Would be an interesting test at least.

[mateuszbrzezinski]

I'm experiencing same issue, V2.4 with AB-BN-25 cooling
But how bad it looks it depends at what angle you look at and if the light is harsh or not.
On both pictures there is same print.

[mateuszbrzezinski]

What if that is some bug in Klipper? SKR? TMC2209?
Anyone using Duet to compare this?

[9ary]

I've rebuilt my extruder with my new motor, and I'm not affected apparently. I'm using Klipper on a Duet 2 WiFi (TMC2660), nothing is tuned yet.

[mateuszbrzezinski]

I was printing test cilinders, so there is no any sharp angles, so to exclude such variable. Then that is interesting, when nozzle crosses Y center axis of model, so before crossing this one of the AB drivers is rotating faster, then after crossing the other motor is rotating faster, then funny things happens, I marked point when that happens. So as you can see, on the left of that mark the issues are more visible, then suddenly after crossing the mark, on the right hand side, issues are much less visible, or almost not visible.

Maybe that is something with motor synchronisation?

[mateuszbrzezinski]

Another experiment:
Printed 2 cubes like that:

You can see the difference.

Part printed at 90* angle front side:

Part printed at 45* angle:

But other interesting thing is part 90* but wall on Y axis are fine:

What the hell?

[9ary]

Interesting results, and puzzling considering bowden extruders appear to solve the problem for others, maybe you're facing a different issue? I also recall that vase mode prints didn't have any problems, but you do.

[mateuszbrzezinski]

@9ary no that are not vase mode prints, that are 30x30x15 cubes, 4 perimeters.

Would be helpful, if other experiencing this issue could do such simple test too, that is 15 minutes print.

[9ary]

The cylinders too?

[mateuszbrzezinski]

@9ary cylinders led me to printing 45* cubes, but anyway cylinders that is another 15 minutes print, so why not :)

[9ary]

I was asking whether the cylinders were vase mode prints, but it looks like they're not.

[Sureiya]

I'm getting very similar artifacts in my newly built switchwire. For reference I'm using an MKS Robin Nano 2.0 with external 2209 drivers. The only reason I'm posting here so soon is that I noticed the shaft assembly pictures. I couldn't get the set screw out of the BMG clone's shaft, so I was not able to reposition the extruder gear on the shaft assembly and believe this is what is causing my problem, as the alignment seems off. If anyone has any tips for getting this really crappy set gear out I can test.

[jurisv]

Same here. Reference build with AB and print size 350mm. TMC2209 drivers. When printing PC it was less obvious, now with quality ABS filament from KVP having the same vertical banding issue.

[fabe83]

I am using a Voron 2.4 250 with Afterburner (Direct Drive). For this I used Orgnial BMG components. 2x SKR 1.3 + TMC 2209 driver.
I have the same artifacts on my prints. I made various test prints, depending on the extrusion multiplier, the artifacts get worse.
I have calibrated everything as well as I can. Input Shaper and Pressure Advance seem to have only a minor influence.
I've already completely re-printed the afterburner, replaced all mechanical components, the hotend, and I'm still waiting for new steppers to test them.

[perikanttila]

I can confirm i have the same issue with afterburner and it dissappears in bowden setup. I do have my own metal corexy printer, no play in any means. What I am going to do is make sure that the 40mm Bowden tube is not pressed down, and will also support it inside heat sink (e3d) so that it can not wiggle. I will report here of my findings.

[perikanttila]

No difference what so ever.

[raymondh2]

This is an issue that is not isolated purely to Voron printers. Given the broad reaching impact beyond just this community, we are closing this issue until a solution is able to be determined for the betterment of the 3D printing community as a whole.

[perikanttila]

Wow head in sand

[Gizzzle]

This is an issue that is not isolated purely to Voron printers. Given the broad reaching impact beyond just this community, we are closing this issue until a solution is able to be determined for the betterment of the 3D printing community as a whole.

Well, this is not the reaction of the voron devs I expected. It's clearly a Clockwork related issue which only the Voron CoreXY and CoreXZ printers had. Because of this I expected atleast a public message at the discord channel which informs the whole community about the problem and confirms that you work on a solution!

[JustinCaseOfWolf]

@raymondh2 there are plenty of printers that do not have this issue. for a top printer voron should be printing top and this issue is not present in ender for example which costs a fraction of a voron.

[herexx6349]

I can only agree with this. When you enter voron discord, you get the impression that you have joined an elite community. A community that positions itself so highly that other products and solutions are often dragged through the mud and ridiculed. Most of the pictures in the showcase were taken in a light where the problems are not visible, which led me to build this "perfect" printer. The fact that the problems exist has been ignored for two months and none of the dev's have commented on the problem. Also, there are no pinned messages warning newcomers about possible problems...

[federico-galli]

This is an issue that is not isolated purely to Voron printers. Given the broad reaching impact beyond just this community, we are closing this issue until a solution is able to be determined for the betterment of the 3D printing community as a whole.

Can you give any reference to this? In this thread every post is about an Afterburner setup. If other people using the Afterburner on 3d printers others than Voron are facing the issue this could be an Afterburner issue. Perhaps who is not facing this problem could share his Afterburner setup so that is possible to debug

[FHeilmann]

This issue was closed and locked 6 months ago for the following reasons:

• Issue 6 is not specific to the Voron Afterburner, it also isn't specific to VoronDesign printers and therefore this repository was deemed a suboptimal venue for discussing, analyzing and solving it.
• The identification of the issue itself and possible solutions was diluted by the following factors:
  • Non-standard or modded printers
  • Other extrusion or tuning-related issues
  • Non-standard identification methodology.
• As a result a lot of the discussion got derailed to "is it issue 6 or is it something else" and "is it my modded extruder or is it something else" .

That said, we do not believe that issue 6 doesn't exist or that it definitely can't be solved. Given the nature of the issue, though, a lot of strict testing parameters and careful investigation are required. We continue to investigate this issue internally, striving to create such a strict and stable set of testing parameters to reliably identify the source of this issue and possible solutions (if they exist).