extruder drips

[pockwoo]

Hi everybody,
I have finished the assembly of my Geeetech Acrylic i3 Pro B (my first 3D printer) and everything is working perfectly (axis movement, bed/extruder heating), except the extruder.
I'm not sure what's going on and I did a lot of searching , but I didn't see anyone having a problem exactly like mine.
The extruder extrudes balls. Literally. I've attached a picture. Click for a larger view.


I'm using a brand new roll of U3Print PLA Basic plus 1.75 mm. The filament just bubbles on the nozzle and drips down when big enough.
I've tried playing with the heating options - tried 180-220C, but without much difference.

Have I done something wrong with the configuration of the printer or is a part in the extruder/filament bad?
I'm running Repetier Host with Slic3r (imported the settings config.ini file, provided in the instruction manual).

Thanks!

[rotormansa]

How long does it drip for? Mine drips too if I leave the printer on any length of time but eventually stops dripping apparently when the extruder tube melts all the filament or melts enough away at the melting temperature. I typically have a dump spot where the head parks but it's not a lot of plastic.

[pockwoo]

It actually doesn't drip by itself when idle. It starts to create these bubbles when extruding (while printing an object, extruding via the "manual control" tab in Repetier, or just by pushing the filament by hand). It doesn't extrude a thin filament line, just the blobs.

[rotormansa]

How old is the PLA and has it been vacuum sealed with descant? I've not experienced it but PLA picks up moisture in about 6 months and the results are blobs in the prints. You may want to pick up a a sample pack of some PLA for a few bucks to see if you get different results.

[pockwoo]

I bought the filament after the printer arrived (it's a week or two old). The filament came in an air-tight bag with a one of those moist-absorbing packs.
I checked and it bends ok (doesn't break) and is the right diameter, so it shouldn't be old I guess (after a quick google search for old pla test).

One thing I've noticed is that the filament needs a lot of force when going through the extruder (when applying by hand). Could this be a sign of a clogged extruder?

[rotormansa]

If stuff is coming out it's not clogged. I did find a PLA provider here in the US (US made) that advertised 185C as the extruding temp and I was having a heck of time trying to get acceptable prints at 220C. I tried 195 through 220 running the test cube calibration excercise but just horible results. Skipped lines, extruder slipping (click, click, click rather than pushing the plastic through the hot tube). I contacted the vendor and asked what's up... I'm glad I did. They apologized about the 185C on their website, the correct temperature is 230 to 235C for PLA!!!! Sure enough, ran a couple test prints at higher temps and no more slipping of the extruder and good prints.

In you case, crank the temp up a bit on the extruder to see if the filament goes through the nozzle easier.

Someday I'll make a video of my learning experiences on this machine. There are a lot of vids out their now, but not many have been real helpful... the test print was one of the more helpful vids.

Gud luck.

Rotormansa

[pockwoo]

I just tried with extruding using the provided sample in the kit, but the effect was the same. I noticed that before the bubble is formed, the filament curls a bit, which as I read, might be a sign of a partial clog. I'll try to clean it and report back.

Thanks for all your help!

[pockwoo]

I finally had time to look at the issue.
The problem disappeared after I carefully cleaned the nozzle with a really small drill. Now the filament flows in a nice an straight line from the extruder.

[William]

I finally had time to look at the issue.
The problem disappeared after I carefully cleaned the nozzle with a really small drill. Now the filament flows in a nice an straight line from the extruder.

Glad to hear that.