Odd defect in print copies - only with Cura

[comyz 0]

Hello,

 

I have an odd defect in a model that appears in all of it's copies. There are 15 models on the plate, and the defect appears in the same place in all of them. I have 3 different printers and the defect appears in all although can change slightly between different settings. The issue doesn't appear in Slic3r at all. Attached are photos of the models.

 

The first image is 15 of the models on one build plate with the defect in the same place on all

 

 

The second is models from different batches of 15 with slightly different settings - temperature, fan etc

 

As I say, in Slic3r this defect isn't there, But I prefer Cura and can't work out what the issue is.

 

The model is printed essentially with 100% infil for all of the upper section so it can't be the infill patten etc

 

I'm use a 1mm nozzle and this is PLA - at everything between 200C and 260C, different speeds from 35mm/s to 60mm/s, different fan settings between 40% and 100%, added and removed hozitonal expansion at 0.02mm and -0.02mm. None of these really make a difference apart from each time the model is slice this defect moves ever so slightly. 

 

 

 

Thanks in advance

 

[burtoogle 513]

Hello @comyz, could you please attach the gcode file so I can take a look. Thanks.

[comyz 0]

Sure - attached is one version

PL3_HORZ.gcode

[burtoogle 513]

Hi @comyz, that's a puzzle to be sure. My only thought is that you are over-retracting and the nozzle is sucking in air which gets expelled later. Are you using 6.5mm of retraction at 25 mm/s in Slic3r also?

[comyz 0]

Possibly not, I think it may be defaulting at 1.5mm. What do you recommend and I'll re run it?

[burtoogle 513]

Depends on whether it's a bowden extruder or not. If it is, try 4.5. If it's a direct extruder then 1.5 could be right.

[comyz 0]

You were correct, changing the retraction to 1.5 solved the issue. Thank you!