Extruded filament going upwards

[hoolito]

Hi all,

We finally got the printer running and we're happily getting to know all the buttons..

I wanted to upload a video of this but the extension .mov is not allowed. Anyhow, I suspect a lot of you will recognize this phenomenon!

If I understood correctly, there is a macro added to every gcode that executes a cleaning routine at the beginning of every printing process. First touching home, then up, then sideways to a position and then extruding some material to get the plastic flow steady and controlled.

The problem is that almost every time, this flow comes out of the nozzle but gets pulled upwards (like a satanic magnetic force pulls it back to the extruder!! ) instead of piling up on the bed nicely and then it begins to stick onto the nozzle making a mess!

Any ideas on how to work around this? At the moment, we are chasing the extruder nozzle with the tweezers, constantly trying to scrape and remove this material, because if the nozzle does not start in pristine condition, the print will invariably get dragged away....

My guess is that this is caused by the fanduct causing some air turbulence... correct me if I'm wrong..

Cheers to all!
Julian

[oregano]

I'd also have a close look at the hole in the hot end.

I had a very similar issue, and it was caused by a distorted hole (which was caused by me using the 'flossing with a guitar string' trick to clean the nozzle - I don't recommend this by the way).....

In a similar fashion, maybe there is some detritus in the nozzle - try forcing some filament through (e.g. get the hot end up to say 220, and extend/retract the filament at high speed) to see if you can shift it.....

Whatever you do with the hot end - just remember it is made of very soft material (aluminium) - so don't go prodding it with things......