Blobs z-seam and irregularity

[VBRS 0]

When printing round shapes I get big blobs at the z seam, and in the case below I also get a irregularity left below on the picture. I printed this file several times and each time the irregularity happens on the same spot. So i have the following two questions:

1. How do i get rid of the blobs at the z-seam? (What I also see is that both wall layers are printed in opposite clockwise directions. I would expect less blobs if it would continue to print in the same direction per layer. Is this a setting I can change?)

2. Why is there an irregularity that keeps happening at the same spot? 

 

Specifications of the printer and model:

- Ultimaker S5

- Nozzle of 0.8 mm (with a nozzle of 0.4mm there are no problems in this model. But I want to lower printing time by using the 0.8 nozzle)

- Wall thickness of the model is 1.6 mm

 

What i have tried so far:

- Z Seam alignment to random -> Gives a lot of ooze and blobs

- Enable coasting (with the 'standard' values that cura gives) -> No change

- Increase the retraction speed -> Not a better result

 

 

 

UMS5_Ontwerp 4.3mf

Edited November 8, 2022 by VBRS

[bp781 0]

https://teachingtechyt.github.io/calibration.html#retraction

[MariMakes 204]

Hey @VBRS,

 

Welcome to the Ultimaker Community 🎉

Sorry, it took us a while to get back to you 😞 

I had our Profile Experts take a look at your question. 
They think it's related to cooling.

Did you check the quality of your fans is there any debris stuck?
This looks like an exotic material, are you printing too warm?
Do you have the same result if you return your print speed to 45? Than the layer has enough time to cool down.  
Another way to cool down is to add a high Minimum Layer Time. 

Hope this helps 🤞