Makerbot 2X Filament Extrusion Problem

Hello,

My school has a couple of Makerbot 2Xs, and they haven't been very well taken care of. They're just over a year old and they are constantly used - with little to no maintenance. I've recently had some time to work on the printers, and with the school year starting up, I want to make sure they are all working properly. I spent a few hours yesterday taking apart each extruder, cleaning it out and removing stuck filament, and cleaning the nozzle heads with acetone and steel wool. As I started to do some test prints, it quickly became apparent that only one out of the four printers was working.

Two of the printers have a problem in which, after a couple minutes, the filament almost stop extruding. It still comes out, but it's very spotty and weak.
Looks like this: (sorry I'm having problems embedding the picture in the forum)

http://imgur.com/U0dw7rw

When I unloaded the filament to see if it was clogged or something, this is what the end looked like (sorry for the blurry pic) - and no, it wasn't visibly clogged.

http://imgur.com/Zm1q5Pv

This print was done on the Makerbot default settings - 230 deg C for extruder, 110 deg C for bed.

Another problem two of the printers share is that when I go to load the filament, the filament can't get through the nozzle. The feeder gear catches the filament and aligns it into the nozzle, however it never comes out. I'm thinking the nozzle might be clogged (although I did not see anything visible). Am I correct in this assumption? The filament is melting - when I unload it from the extruder, the tip is slightly melted and bulbous, so I don't think the heating core is the problem.

Any ideas on what could be causing these problem?
Thank you so much for your assistance!

As I understand it the ABS filament absorbs water if left in the air for a long time. Sounds as if you have some of the symptoms I have heard about.

Quote:

Originally Posted by mystic

As I understand it the ABS filament absorbs water if left in the air for a long time. Sounds as if you have some of the symptoms I have heard about.

Hey, thanks for the reply. I do believe this was part of the problem. I'm slowly addressing each problem printer by printer and I've fixed the majority of them.
A couple of the nozzles were in dire need of being replaced. So I replaced those and those extruders are working pretty well now. I also used new filament, which helped. The filament I was using before was a few months old, so I can see why it may be giving problems.

Thanks again!