Air in extrution?

[3DFrost]

OK, so I've been trouble shooting my H-1.1 for over a month, still haven't gotten but a very rudimentary print, and even that was just today.
Currently my problem is with my extruded filament, it expands to 1mm after coming out of my .5mm nozzle due to air in the extruded filament. In addition
very large bubbles sometimes form in the extruded filament but I can't seem to figure out why. The filament was extruding fine for a while, but then got
clogged prompting me to open up extruded and remove the derby, after this is when the air effect started occurring.

So any ideas on why this is happening and how to fix this?

[michaellatif]

Have you tried to 'flush' out the air? You may have to run the extruder for a little bit (push 6-8 inches into it).
Otherwise the filament is to blame. I have found that air comes from cheap or poor quality filament and it causes it to expand on exit of the tip.

[3DFrost]

Ya, I've tried to flush out the air several times and it didn't seem to have much effect.
I think however it might be the teflon tube which I damaged somewhat when trying to
remove it when cleaning the extruder and is now somehow gulping air. It could of course
be the fulfillment as you said, but that wouldn't explain why it wasn't doing it before.

[Fiero2M6]

Are you printing with PLA? PLA is hygroscopic, and I usually throw it in a ziploc bag with a dessicant when I'm not going to be using it for a while.

I don't think ABS has this issue.

[3DFrost]

No. it's abs
After dissecting my filament under a microscope I found that michaellatif is right.
I don't know why it wasn't this way before but in their is a long continuations (almost purposeful seeming) hollow center to the filament I bought.

So anyone know of any good NOT MASSIVELY EXPENSIVE filament?

[Polygonhell]

I like Ultimachine, it's really very consistent, the cheaper stuff I've bought has been inconsistent, and IMO is just not worth the hassle.

[michaellatif]

The only filament I have not had problems with is Ultimachine's. The cost is a bit more then you can get via e-bay or other cheaper sites. But it's not that much more, $18-$20 per pound of ABS.

[3DFrost]

$18 a pound is a pretty good price, would you happen to have a link?

[michaellatif]

http://ultimachine.com/content/abs-3mm-natural-5lb <- $15/pound you have to buy bulk

If you use 1.75mm filament, its a little more

http://ultimachine.com/content/abs-175m ... lb-spool-0 <- $20/pound