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vakil
(@vakil)
Eminent Member
White blobs on infill

I am using a new hardened steel E3D ObXidian Prusa Nozzle on my XL.  On a large print the brim and first 3 layers are perfect.  The infill starts OK but gets little blobs that over time push the nozzle aside, cause gaps, and in general put the entire print in danger.  The picture shows the issue.  I got the nozzle to print wood filled PLA and that print had no issues.  I also did a print with PETG and there were similar issues that I attributed to the nature of PETG.  Now this print is PLA , I need four of them, and each one takes 29 hours.

First layer temp 215 degrees, other layers 210

Perimeter speed 70 mm/s  Infill is 80 mm/s  (First layer speed is 30)   I am using 10% infill, support cubic

Extrusion multiplier is 1

Any ideas?  Missing information that would help?

Thank you, 

 

 

Posted : 29/05/2024 9:17 pm
BaconFase
(@baconfase)
Estimable Member
RE:

Is your nozzle adapter leaking?

 

XL-5T, MK3S MMU3 || GUIDE: How to print with multiple-nozzlesizes do read updated replies || PrusaSlicer Fork with some flags removed || How Feasible is Printing PETG for PLA supports on XL very

Posted : 31/05/2024 7:07 am
ntdesign
(@ntdesign)
Reputable Member
RE: White blobs on infill

Everything except the infill looks fine, which is super weird. Are you sure  infill speed is really 80 mm/s? For 0.2mm Quality (no IS) it's already 200.
Maybe it's just that the material cannot deal with the infill speed, can happen when wet and white filament is sometimes a bitch. To me it looks like it's underextruding when doing long extrusions, but only in the infill. Eventually the wall gets too thin, develops a hole and the loose strings ball up.

Test-print with 1 wall and no bottom layers, then you can see faster what happens.

Posted : 31/05/2024 1:44 pm
vakil
(@vakil)
Eminent Member
Topic starter answered:
RE: White blobs on infill

The nozzle is not leaking - one of the first things I checked.  After a lot of testing the culprit was the infill speed was too high.  I had it set at the default, 80 mm/s and I lowered it to 65%.  Unfortunately I did this via the Tune -> print speed which also lowered ALL the print speeds which changed a 28 hour print into a 40+ hour print (It is still printing).   

In essence the blobs are caused by the filament not reaching the gap in the infill and leaving a void, or falling to the bottom or side of the print.  This also idded bumps to the infill which the extruder would hit.  

I am wondering if increasing the Extrusion Multiplier might be a better approach - as well as increasing the fill density from the current 10%.   

These prints are large so I focus a lot on print speeds.

Posted : 31/05/2024 2:07 pm
ntdesign
(@ntdesign)
Reputable Member
RE: White blobs on infill

Then my advice is to dry the filament, and if that doesn't help just switch the brand. With cubic style infill patterns and PLA you can easily get away with 300mm/sec.

Posted : 31/05/2024 2:17 pm
vakil
(@vakil)
Eminent Member
Topic starter answered:
RE: White blobs on infill

Thank you for the reply.  I did not mention the filament because it was a new reel from a brand I have been using for a long time so I did not think it needed to be dried.  I went through a series of tests - was it the Nozzle (no), was it the extruder (no), the filament (no, it is working just fine).  The only change I made was to lower the speed from 80 mm/s to 70 mm/s.  It would be interesting to see if a dramatic increase in speed would work as well.  When you get 300 mm/s on a cubic infill what  are the other parameters; e.g. specific infill, and infill percentage?

Posted : 31/05/2024 4:59 pm
ntdesign
(@ntdesign)
Reputable Member
RE: White blobs on infill

0.2 Quality is my go-to profile, I don't care for speed except for occasional prototypes. Usually to bump it up I start with that profile and just increase the values until it fails, sometimes I add +5° to the temperatures as well. But mind that all this is not really worth it unless you know you'll need almost the same print 20 times and it takes long. If you optimize too much you'll waste the time there. 200mm/s is already fast and reliable and doesn't really depend on the filament. Stick with cubic, it's the best all-around compromise in my opinion. I sometimes use gyroid if I need isotropic stability with minimum weight, but it's a nightmare to print at default speeds on the XL. 

But all this doesn't change the fact that something is wrong here. It could be just your current spool, I have a brand I use for everything and they're very consistent but one in twenty is just wet. Are you sure it's not something mechanical? If you look closely at your picture, the top bottom layer seems to have a tiny blob on the diagonal lines every cm and it looks very regular. Anyway, my advise would be to go back to a stock profile and start with a temp tower print using that same spool. Maybe you're just printing a bit too hot.

Posted : 03/06/2024 6:58 am
vakil
(@vakil)
Eminent Member
Topic starter answered:
RE: White blobs on infill

Hi ntdesign,

Print time, i.e. speed, is my issue.  Virtually all my prints run 22 - 36 hours.  The largest amount of time is on infill which, as I mentioned, I am printing at 70 mm/s.  I'd love to see how I could print infill at 200 mm/s - so I have a request.  Can you email me a .3mf of anything that is printing infill at that speed using adaptive cubic or something similar.  I want to look at all of the print parameters.

Separately, I agree that there is something mechanical.  I know it is not the nozzle and I think it might be the extruder itself.  I am using a different extruder and hopefully that will work nicely.

Thank  you - my email is [email protected]

 

 

Posted : 05/06/2024 5:48 pm
ntdesign
(@ntdesign)
Reputable Member
RE: White blobs on infill

Better use PM to trade email 😉

Posted : 05/06/2024 6:04 pm
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