Small Circular Features Don't Extrude

[spencerdiniz 0]

Hi all, 

 

This is my first post here, so go easy on me! 😂

 

I've been using "legacy" Cura for quite a while and have been pretty satisfied with the results.

Then I watched a YouTube video where the person was using Cura 3.6.0 and I was amazed by all the new features and settings.

So I decided to upgrade.

 

All was going well, until I printed a part with small circular (tubular, cylindrical) features that extend upwards from the main part. 

The cylindrical features, about 5mm in diameter, weren't extruding at all. Basically, the only filament coming out was due to oozing. 

So I tried a Benchy and it printed perfectly, except for the chimney, which is a small circular feature.

I tried other models, same thing, small circular features don't extrude.

 

So I went back to "legacy" Cura and tried these parts again. They all printed perfectly.

Then I tried Slic3r and all parts printed perfectly also.

 

The problem is, neither Slic3r and "legacy" Cura have all the cool new features and settings found in Cura 3.6.0. 

Has anyone else had any problems like this, where small circular features don't extrude at all?

Any suggestions as how to fix this?

 

This is what I'm using:

Anet A8

0.4mm nozzle

Heated Bed (70 C)

PLA (225 C / 1.75)

Print Speed (20mm)

Travel Speed (60mm)

Layer Height: 0.2mm

Walls: 1.2mm

Infill: 20%

 

Thanks!

[burtoogle 513]

Hello @spencerdiniz, welcome! To help us understand what's going wrong. Please save the Cura project (File->Save) and attach the .3mf file to this thread. Thanks.

[spencerdiniz 0]

Hi, @smartavionics,

 

Thanks for the quick and courteous reply. 

Sorry for the noob oversight. Here's the project's .3mf file. 

 

I have also attached the "Project Summary" dialog that appears before saving the project.

I've noticed that it nozzle is "undefined". Could this be related?

 

I did input the nozzle settings (0.4mm), so I'm not really sure what additional information I need to provide in order to have a "defined" nozzle. 

 

Thanks for the attention and time... 

 

Best regards.

Spencer

 

 

CFFFP_Key Hook.3mf

[burtoogle 513]

Hello @spencerdiniz. I don't know what undefined means in the above project summary, I get the same for my printer (a Kossel delta) so I wouldn't worry about that. I printed a couple of the hooks on my machine and they came out fine. With parts like this, cooling is the key to success as they tend to overheat due to the small area so I am using 100% fan.

 

The picture shows the part cooling nozzle pointing right at the (naked) hotend heater block which is not going to help at all as it will be cooling the hotend. Is that why you are using such a high temp (225 for PLA?) I am currently printing PLA at 200 with the bed at 45 and get very good results.

 

Looking at your project, I wonder whether you are over-retracting? I think your printer has a direct drive extruder (not Bowden) and 4mm of retraction sounds an awful lot. I'm using 4mm of retraction with my Kossel's Bowden extruder and another printer I have which isn't Bowden is using 2mm of retraction.

 

Hope this helps!

[spencerdiniz 0]

Hi, @smartavionics,

 

Once again, thanks for the quick reply. 

 

These are great suggestions. I’ll give them a try today and report back the results.

 

Thinking about it, the retraction seems suspicious... Since the circular feature is so small, could be there’s more retraction than actual extruding. Which would explain the lack of any extrusion on these features.

 

Thanks! 

[spencerdiniz 0]

Hi, @smartavionics,

 

I tried your suggestions, but still the same problem. 
Cura 4.0 was just released and I gave it a try, but also the same problem. 

 

I went back to "legacy" Cura and it's working -- no problems with small circular features.

I'll continue to experiment with the settings in Cura 4.0 to try to find the problem. 

Meanwhile, I'll keep slicing with legacy Cura or Slic3r. 

 

I'm also considering Simplify3D...

 

Anyway, thanks for the attention. If you have any other ideas, please, let me know.

 

Best regards,

Spencer

 

 

[burtoogle 513]

Hello @spencerdiniz, please attach the cura gcode that gives a good result and also the cura gcode for the same model that gives a bad result. I can then compare the gcodes and see where they differ. Thanks.

[spencerdiniz 0]

Hi @smartavionics,

 

I have attached 2 .gcode files to this thread.

 

One called bad-results.gcode (Cura 4.0) and the other called good-results.gcode ("legacy" Cura - the about screen doesn't have the version number). 

 

Thanks, once more, for your attention. 

 

Best regards,

Spencer

 

 bad-results.gcodegood-results.gcode

[burtoogle 513]

Hello @spencerdiniz, a quick look at those files shows me that the good result was printed at 200 deg and the bad result is using 225 deg. As I mentioned above, that's pretty hot for PLA and you can expect to get very different results compared to using 200 deg.

 

The other obvious difference between those files is that the good result does 3 walls at around 20mm/S and the bad result uses 2 walls at around 20 mm/S and the outer at 10 mm/S.

 

So I suggest you try using 200 deg and 20 mm/S for all the walls and see if that makes a difference.

[burtoogle 513]

Ah!, I just noticed that in the bad results file you are using relative extrusion. That would explain the poor print quality if your extruder resolution is low. Try using absolute extrusion rather than relative.

[spencerdiniz 0]

Good news, @smartavionics. 

 

It worked! I turned off "Relative Extrusion" and it printed perfectly. 

With the other tweaks (temperature and retraction) you suggested, it's printing even better than before.

Thanks so much for your time and attention. 

 

I've seen in other forums people having the same issue as me. 
I'm going to refer them to this thread. 
You'll make a lot of people happy!

 

Best regards,

Spencer

[burtoogle 513]

Hi @spencerdiniz, I'm glad the problem is solved. I still think you would do well to stop the print cooling fan from blowing onto the hotend block. Cheers!

[spencerdiniz 0]

Good morning, @smartavionics,

 

This is how the fan nozzle has always been since I assembled the printer. I don’t know any other way to position it. 

 

What would be the correct way to point the fan nozzle? Do you have a picture or illustration of a correctly positioned one that I can use as reference? 

 

I’m going to do some research to try to figure it out. 

 

Thanks. 

 

Best regards,

Spencer