Calibration process

[Khayrisill]

Hi everybody !
I finish the assembly on my Rostock Max V2 ! Look awesome So i start some calibration step.
I have found some default on parts for the FAN. I was trying to find if the retractation parameters are good. While i print my parts (the square one) i realise that we can heard a sound when the filament is extruded ( crackling like a wood fire) each time it's happens à small blobs appear on the surface.
Someone has an idea ? Because when i extrude manualy the filament everything it's ok.

I print with 1.75 ABS black filament. At 220°c

[Jimustanguitar]

That's usually an indication of filament with air bubbles trapped in it.

Inspect a section of it for imperfections. You can feel the bubbles with your thumb nail, or if you have a way to pull and stretch it, you might notice air bubbles that show up as stretch marks.
[img]http://i.imgur.com/kEfh0as.jpg[/img]

[Khayrisill]

Well..., I can check tonight. if it is that, it is really a poor filament... :/
But the point is, when I extruded manually, no noise and the filament at the hotend look good.
Its possible when the filament are retracted the air go inside the head ?

Edit: I check the filament, nothing spécial. I read here and on internet the Hatchbox is not really a good one..

I decrease the the retractation distance, its better but not perfect.