Makerbot Replicator 2 not extruding during print

Whenever I load my printer, the filament will extrude fine. I've let it run for about 5 minutes and it will keep extruding the entire time. Whenever I start a print it stops extruding.
I've leveled the bed, cleaned the nozzle, reassembled and disassembled it, and changed the filament multiple times.
I have it set to 240C and am using PLA

Hi there
if extruding works ok and extruded line is thick, then I would check distance between nozzle and build plate.
If nozzle is leveled too close to build plate then it can't extrude while you start your print job.

and for pla 240 is too high.
210 is my standard for pla - 220 absolute max.

But yeah, you may just be calibrating too tight.

Try something small and see if you get filament on the second layer.

Quote:

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Originally Posted by curious aardvark

and for pla 240 is too high.
210 is my standard for pla - 220 absolute max.

But yeah, you may just be calibrating too tight.

Try something small and see if you get filament on the second layer.

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We actually recommend to print at 230°C. 240°C is definitely too high though. Double check your leveling. This is a good model to use:

http://www.thingiverse.com/thing:45459


When preparing it for slicing, make sure you are NOT using a raft. Use MakerBot Desktop's standard resolution settings. Once you've done that, start the print and keep a close eye on the first layer, ready to make small adjustments with the thumb screws. If the extruded plastic looks 'gloppy', or 'cylindrical', then the nozzle is too far from the platform. If the plastic is extruding intermittently or not at all then the nozzle is probably too close to the platform. There's a thin line between the two, but that's the height you're looking for. At this height the extruded plastic will look 'squished' or 'pressed'. It very well may take a few prints to get the platform at the correct height.

You should also make sure your fan is facing the correct direction. The silver sticker on the fan should be facing the heatsink blades. Here is a photo to help:

Attachment 6792

I leveled it several times and changed the temp to 230 and it is still giving me the same problems :/
The fan is facing the correct way as well.

I run the 3d printing lab at a technical school and so far none of the other staff has been able to figure out what is wrong either.

Hi there
I would suggest to take it to Makerbot Service center.
Your printer is most likely fine, just need to be serviced a little and will the job just fine. :)

Regards
Roberto