Retraction problem

[x3nomorph 0]

Hello everyone,

yesterday i changed my filament to ABS colorfabb xt white (first time abs), but i had the same problem on PLA also.

Every time when the printer using retraction and traveling to the next part there comes a little bit of plastic through the nozzle and it creates bubbles on the other part, i though that is ok and it wasn't that hard to remove them. But from time to time its more complicated to remove them and i want to ask is there a way to completely avoid them?

https://www.dropbox.com/s/vs5hqpq5momqrho/DSCN1232.JPG?dl=0

https://www.dropbox.com/s/17b4efueppkr4dx/DSCN1234.JPG?dl=0

Model printed with 0.1 mm layer height, 40 mm/s speed (later dropped to 80%), bed 90°C, temp 250°C (later dropped to 240°C - what is the minimal for xt white).

PS. i broke the rules, i tried to play with the fans and i got the best result at 100% fan speed, i read everywhere about turning off fans but i had weird curlings on the overhangs so i turned them up.

On the last pic there are shown some "burned" areas, don't know the reason for that...

https://www.dropbox.com/s/lbfwtilfutrl20j/DSCN1238.JPG?dl=0

Thanks in advance.

 

[DidierKlein 729]

Just for information Colorfabb XT is not ABS it has similarities in terms of strength and glass temp but without the horrible fumes of ABS.

No for the blobs, i don't have much experience with XT yet but it's similar to stringing, in my own experience i think the best way to reduce this is to increase the travel speed, the UM2 can go up to 250mm/s with no problems.

Maybe try that.

Or adjust the retraction settings (on the printer) but i have no particular parameter to give you, you can tune them on the fly in the tune menu to find out what works best.

Lower temperature will help reducing this and lower speeds too, but with XT it's difficult to go under 240°c

 

[Labern 774]

I have printed XT at 220deg but you start to get layer adhesion problems.

also make sure the bowden tube is firm in the connectors at each end so there is no movement.

and using fans with XT is fine

 

[x3nomorph 0]

Hello, thank you for the answers.

I though there is only pla and abs, from the temperature i though that is abs, thanks for correcting

I reduced the blobs a bit by increasing the traveling speed, lowering the material flow to 100% and decreasing the temp to 240°C. I tried the retraction settings on the machine but nothing changed. I don't really understand the option "minimal extrusion before retracting" in the expert config? This could maybe solve this problem?

Thanks