Continued: Problem with quality on round objects

[fredric]

This is a continuation of this issuse that I reported recently:

Spaggeti after many layers on standard speed with bambus filament

Hi! Any suggestions welcomed here. This print failed after maybe 20 layers with major spaggeti. Everything is standard. Speed etc. The filament is Bambus own PLA-CF. Printed with AMS. With supports.(tree) But the layers where this was needed was never reached. What can cause such errors?. Where do i start experimenting to get a successful print?. [IMG_7083808]

After some tests based on user feedback on the last post (where everything went spagetti), i have now pinpointed the problem to be “large circles” ? I know. But i lack a better explanation

I tried printing out bits and pieces of the original project and the printer seems to have huge problems with thin walled hollow piping
When printing a smaller or more solid object it seems to work fine.

The test i did was a simple round piece that is 4 mm thick. The print does just scatter in your hands and it seems to lack the upper surface completely. Also almost see-thrue. The object to the left in the first images is printed with the exact same preferences and looks and feels ok.

I also reprinted some stuff from the machine itself (the scraper) and these looks fine.

I tested more wall loops but same results

[Thrawn]

Did you dry your filament? That looks quite horribly.

And does it happen with all large circles, so if you add a primitive directly in the slicer, does it happen too?

[fredric]

It prints other things just fine and the room humidity here is 35-40% so it shouldnt be that.

I tested a few larger circles but will try some smaller also.

Can i add a primitive in the slicer?.. I will test that

EDIT: I can add a cylinder but how do i edit the size and make it hollow in bambustudio?

[ThanksForAsking]

@fredric

It prints other things just fine and the room humidity here is 35-40% so it shouldnt be that.

Ahhh, not to be rude, but that’s not true. That level of humidity can totally cause filament problems. I agree with @Thrawn , that absolutely looks like damp filament.

I just had this discussion elsewhere that we have a tendency to go after settings and calibrations while often overlooking the plastic itself. That a filament arrives properly sealed does not mean it is dry.

This 3D stuff can be complex. Learning is the key to success. (He says in his best Professor voice )

Here’s an article on the subject to get you started. If you really wish to fix this issue, listen to people who have done this for years, eh?

We’re here to help, but you get to do the work … this will help.

Filaments and Moisture Absorption; Complete Guide! – 3D Solved
This is one of many guides out there on the subject.

Now, this may not be what the problem is, but it sure looks like that from the pics. As I said (and you’re finding out!) this stuff can get complex, but it starts with the filament.

We’ll be here to help ya!
Cheers!!

[Thrawn]

You can change the size via the scaling tool (shortcut s). Then right click the cylinder and add negative part. Choose another cylinder that is slightly smaller and you are done

[fredric]

I hope i didnt come out as rude. That was not my intention at all. Since the same filament roll prints out other objects just fine with no artifacts and a nice finish, i thougt it couldnt be that. I will definatly read the article to learn more.

I dont make a secret of being a NOOB. Just hit me with your great knowledge.

[fredric]

Perfect . Thanks. Will try that-

[Jrock]

Are you printing inner walls first or outer walls first ?

Also what is you layer hight and line width ?

I would suggest reversing your wall printing order and increasing your line width a touch

Also helps to slow down the outer wall speed with the caveat of ripples on the outer wall surface

I will also add if you are using classic wall generator try arachne or if you are already using arachne switch back to classic

I’ve found depending on the models geometry and size that one group of settings alone will not always work especially when there are lots of triangles in the mesh or the part takes up the whole build plate rather than just the center portion

The fact that you can print other models fine tells me you’ll just need to tweak your settings

Sparse infill percentage also plays a factor in all of this along with the wall overlap and top and bottom layer count

You may want to increase your top and bottom layers to 6 on a more fine quality print and try 100% infill

[ThanksForAsking]

@fredric

I hope i didnt come out as rude. That was not my intention at all

Nah, Not in the slightest!!

@fredric

Since the same filament roll prints out other objects just fine with no artifacts and a nice finish, i thougt it couldnt be that. I will definatly read the article to learn more.

No problem! I just looked at it and thought “damp filament” then Thrawn said it and I decided to post something to help.

Reading my reply, I didn’t want to com across as a know-it-all! LOL Text messages are hard sometimes!

No worries, we all were there, I still feel like a n00b!! We all help each other, my Friend.

If you’d like some other articles on this I have a couple more good bookmarks.

[fredric]

Thanks for alot of great tips

Im gonna try them and i think you are right about the tweaking parts.

I just successfully printer a hollow cylinder by creating it in the slicer directly and using 3 om wall cout and 4 on top and bottom.

The object i wanna print still has issues though.

[print.in.3d]

@fredric, have you tried to print the object with other filament?
In the last days I have printed nearly 30 parts, which contains a bottom with 2 hollowed cylinders on top with a diameter of 18 mm and 90 mm and a height of 13 mm, with two different filaments (PLA). All came out beautiful without any problems.

[fredric]

Im still waiting for new filament so im stuck with the PLA Bambu sent me. Im starting to think my problem lays in the actual 3d model… When printing cylinders directly created in the slices , it works perfectly.

[Thrawn]

Can you share the STL? Could have a look then

[ThanksForAsking]

@fredric

Im starting to think my problem lays in the actual 3d model… When printing cylinders directly created in the slices , it works perfectly.

Besides sharing the model, try LEFT clicking then RIGHT clicking on the model and choose Fix Model. Sometimes models have mesh issues that aren’t visible.

Then print with your last settings.

[fredric]

SOLVED! Thanks for all the help @ThanksForAsking @Thrawn @Jrock @print.in.3d

I have finally solved the issue with a reasonable explanation. It was a combination of bad 3d model and my stupidity.

1. First print of downloaded model failed due to too sharp inner threads and the Bambu PLA-CF not really liking the 0.4 nozzle-

2. The next print where i tried ordinary PLA with a simple cylinder object created in Fusion 360 failed miserably. This was most likely due to the fact that i just changed the filament without syncing the AMS with the slicer. I think it ran with the settings for PLA-CF. (This was the one that looks like moist filament)

3. Following prints after this worked ALMOST ok with the standard PLA filament and the downloaded model but something made all prints really stringy on the inside where the threads are. Maybe a bad object or simly too steep and deep threads.

I ended up re-creating the model in Fusion and the result is WOMDERFUL!!!

.

[Thrawn]

Glad we could help. Looks so much better then the mess from above

[dougal.jackson]

I’m having a very similar issue to what you were having, on three different X1C’s, only when printing cylinders greater than ~50mm diameter. In this case the issue seems to stem from how Bambu Studio generates the G-code on models imported from STP files instead of STL’s.

I discovered the issue while printing with PLA with 0.4mm nozzles, 0.2mm layer height, standard speed. Using Bambu Studio version 1.9.1.66 and firmware version 01.08.00.00 (currently the latest version).

I’ve done dozens of nearly perfect prints with the same material/settings in the last few weeks (importing from STP), but over the last couple of days I’ve been trying to print some cylindrical parts with roughly 80mm OD and 50mm to 90mm ID, and the walls look TERRIBLE - with a very severe, inconsistent ripple pattern in the walls that looks very much like the photos at the top of this thread. So far no outright spaghetti failures, but the worst examples have many blobs and stringing.

Prints still come out nearly perfect on smaller cylinders (~40mm diameter or less) and other shapes.

Definitely not wet filament; I maintain three extra desiccant containers in my AMS’s and humidity monitors inside the AMS’s all reading 10% (the lowest they will read.)

Occasionally, the OD or ID will come out smooth, but so far never both. In a couple of cases, the bottom few millimeters of the OD was smooth but everything above it had the severe ripple artifacts.

While the issue is happening, as the head travels in a circle the printer vibrates more loudly than normal, with a rapid “stuttering” sound from the X/Y chassis, as if the stepper motors are briefly being put under high load by attempting short, very rapid deviations from a smooth circle. This seems to indicate that the issue is related to head X/Y motion rather than filament flow.

I first ran into the issue while trying out the new scarf seam feature, but it happens with and without scarf seams.

I tried the “Fix Model” command but that didn’t help.

Increasing the resolution setting (Quality > Precision>Resolution) from the default of 0.012mm to 0.02mm and 0.03mm does not fix the issue (As suggested by DzzD in post Banding / Ringing type artifacts? - #168 by Jrock).

In all cases, the previews of the STP-imported models in Bambu Studio look fine, with smooth walls and no faceting.

Importing the same models as STL files fixes the issue, but of course the parts have the typical STL faceting. Eliminating that faceting is the reason I preferred (until now) importing models as STP files in the first place.

Turning off Arc fitting produces similar wall-ripple artifacts, but with much smaller magnitude and frequency. The appearance is much better, but still quite a bit uglier than faceted .STL-imported files.