Big Problem with shell finish

[Frutolo 0]

Hi,

 

i am trying to get help this way, as all my recent tries to fix the problem didn´´``'t work.

I am using Ultimaker Tough PLA and Breakaway support on my Ultimaker S3.

Since 2 weeks i get these artifacts on the shell surface. Since then i have 

 

• Switched out the two  print cores  (just switched them, not bought new ones)
• Cleaned the feeder
• lubed the rods
• Checked the tension on the short and long belts
• Changed temperatures and speeds
• Got new filament rolls
• cleaned the print cores

 

and the problem still exist. Any idea what could cause this problem?

[Smithy 1,144]

Which profile do you use for these prints? 

Maybe it is just the photo, but it looks like you use a high layer height?

How fast do you print?

[Frutolo 0]

Oh sorry, forgot to mention that.

0.3 layerhight on 0.4 nozzle, should be fine. I get these artifacts also on 0.2 and 0.25.

I adjusted the engineering profile, speed is 55 mm/s for infill, 35-40 for walls.

[Smithy 1,144]

Try the default engineering profile please without any changes, just to see if there is a difference.
The plus of the engineering profile compared to the others ist that it has equalized speeds, so "tuning" the speeds can have some effects.

 

I don't think it is a mechanical issue, maybe a cooling or temperature problem, but let's see.

[Frutolo 0]

Printed with the engineering 0.15 stock profile, the problem is still there...

[Smithy 1,144]

Strange....

At the moment I have no more ideas.

 

Maybe check if both cooling fans are really working (left and right)

[Frutolo 0]

Is there a easy way to check this?

[Smithy 1,144]

You can only try to look from above with a flashlight. It is hard to see, but it is possible.

[Frutolo 0]

OK, fans are running.  What i saw now is that there is little Filament oozing when travelling. Maybe that could cause the problem?

 

 

[Smithy 1,144]

No I don't think so. But I just have another idea, the last picture looks like that the wall is very thin. So maybe it is a slicer issue that the wall is thinner that the line width and Cura tries to compensate that in a way which is not working or looking nice.

 

So take a look at the preview for that layer and post a picture here please.

[Smithy 1,144]

BTW can you save the project and post it here (File - Save Project) then we can also take a look on it or try to reprint it on another printer.

[Frutolo 0]

This was my  thought too, but unfortunately this error also occurs also on other positions.

I can´'t  send you the file as it is a part for work, but i sliced a benchy to try.

 

What i noticed is, when travelling the nozzle leaves slight oozing on the print. Sometimes the printhead travels over the shell, leaving this oozed material on the shell --> then the shell can't be printed correctly anymore...

UMS3_3DBenchy.3mf

[Torgeir 242]

Hi Frutolo,

 

What i noticed is, when travelling the nozzle leaves slight oozing on the print. Sometimes the printhead travels over the shell, leaving this oozed material on the shell --> then the shell can't be printed correctly anymore...

 

Excuse me, -but this remind me about a beginning issue with the filament. It looks there is to much filament some places and print very nice other places. This occurs when the printer slow a little down..

 

This use to occur if/when the filament have "attracted" a little bit of moist and when printing at "some" high temperature this tend to increase the nozzle pressure just a little so there is some extra flow of filament.

 

To test for this issue, speed up printing and reduce the print temperature. If this work, you'll need to get a filament dryer.

 

I've had brand new filament with this kind of issue..

 

PS: 3DBechy must be printed without using heat bed, this due to overhang close to the heat bed..

 

Just my five pence.

 

Thanks

 

Torgeir

 

 

 

 

 

 

[Smithy 1,144]

@Frutolo I have quickly checked your project file but cannot find any strange settings or something like that.

 

But the idea from Torgeir is good, try it please.

[Frutolo 0]

I have this also with other filament rolls like CPE, and on tough PLA with my last 5 Rolls,  original ultimaker filament, all used within 4 days per roll... I tried like torgeir said and it still has no affect on the print quality...do you print the shell or the infill first?

 

I found a thread where the shell looks almost like mine,  what values do you use for your MAX resolutions settings?

 

[Torgeir 242]

Hi Frutolo,

 

If this is the problem, you will see it in the Cura viewer.

Normally I'll always use default, but sometimes when you see this "pop outs" on the wall I'll try to increase the max deviation.

 

Thanks

Torgeir

 

[Frutolo 0]

Here another 2 pics of how it looks...i just don't get it, 3 weeks ago it printed just fine. I also just can't imagine, what i could have changed (also by accident).

A mecchanical issue should be unlikely right?

[Torgeir 242]

Hi Frutolo,

 

I'll agree, this doses not looks like a mechanical issue.

 

Just in this two picture it is looking like the filament been cooling too much down and being drawn out of the rounded path going into the model and coming toward "us".

 

It seems to work better when the printing path going around the corner, -filament is "stretched" toward the objects corner?

 

I'll tend to think that a strait cylinder will look "much" better on the outside, than the inside, maybe such a test is handy here?

 

Printing with such a thick (high) line (0.3 mm) need flow and heat. Here it's looking like there is too low heat, as filament seems as start to become more dense (cooled down)..  

 

Maybe the filament did not reach the right temperature when passing through the heat block and nozzle?

Hmm., you said you swapped the two AA block.  How many print hour is done?

 

There is a high demand for flow at this way of printing, -so a "small" error may have hi impact of the outcome.

 

However, you should be able to print object with more standard "height", say 0.15 mm., as it will be easier to compare objects of such a print out.

 

Thanks

Torgeir

 

 

 

 

 

[Frutolo 0]

Good idea, i will try to print a cylinder and then also one with higher printing temperature.

I already tried to print on lower layerheight, but with little success (see beginning of the post).

I just switched printcore 1(AA) with printcore 2(AA), i didn't get new ones.

Right now i am at about 600h printing.

[Torgeir 242]

Ok. I've just made a solid cylinder 50X50 mm, standard engineering - normal profile.

Selected 0.3 mm height, single wall, no infill, no top/bottom layer and spiralize outer/contur.

 

Printing now, time 14 minute.  

 

Here's the project file: UMS3_Test_Cylinder_50_X_50_mm_06_10_20.3mf

 

This is the picture of sliced and printed model:

 

 

 

The printer moved around all the way without stopping..

Looks very nice, no issue at all.

The shadows is made by the curtains. 🙂

 

 

Thanks

 

Torgeir

Edited October 6, 2020 by Torgeir
Added text.

[Frutolo 0]

Thanks, i will try to print it as soon as possible.

While invetsing the slice on cura i found another error. The last support interface layer is not totally printed, how could i change that?

[Torgeir 242]

It appear that this support is made in the CAD program together with the model, right?

Are you using PVA as support?  As there is sign of some oozing of white filament here, this might have something with (assuming this is PVA) the support filament to do.

 

Just so it is said, PVA is very sensitive to humidity, more than most of the filaments there is. It might break inside the bowden tube (due to high water contamination) when it's stretched out to follow inside path. The printer might print on while the support suffer and PVA will ooze during this time. The PVA feed will be ok, but the retraction do not work. As the printing go on, the rupture will disappear and PVA will have retraction again.  However, there might be another break coming up soon.

 

Since "those" problems arrived all of a sudden for you, I've wonder if this might happen due to season change?

Colder shop temperature and higher humidity?

I've seen on your prints that there is sign of PVA around, sure this is "kind" of normal, but maybe an issue to consider.

 

As the infill just stop all of a sudden -after this nice printing (PVA), it's very difficult to trace the error just like that.

 

Well, this is all I can come to think about for now.

There might be some other opinion in here that might chime in.

 

Good luck

 

Torgeir.

 

 

Edited October 7, 2020 by Torgeir
Added text.

[Frutolo 0]

I have set combing to "not in skin" now, and it seems to have worked.