MakerBot Replicator 2 nozzle clogged....but doesn't seem clogged...?

[Kody Dagley]

Hey all!

I'm new here, my name is Kody, a tech. intern for South Shore Public Libraries in Nova Scotia, Canada - We're having a little trouble with our Replicator 2 and thought maybe you folks would have some suggestions!

When we first got it, we had a lot of trouble with failed prints as the original extruder / nozzle design is poor because the plunger does a poor job of keeping the filament against the extruder motor gear to feed it through. We ordered one of the spring-loaded replacement upgrade kits that Makerbot sells and we've had almost no problems since (except for a break in the x-axis cable which I repaired by soldering in a replacement patch cable)!

In the last 4 weeks, myself and another intern have been running our Tech Camps for kids at our various branches. All has gone will during the first two camps in Bridgewater and Lunenburg, however, on the 3rd of 4 days during the Liverpool branch camp last week, the printer began to fail while printing, with the prints becoming all stringy and eventually with no filament exiting the nozzle. I've now cleaned the drive gear several times, and have taken a sewing needle and safety pin tip to the nozzle a few times now as well, to ensure there are no clogs...I can push both through until I see the tip peek out the bottom of the nozzle, yet, on the next print, it will still fail randomly with the same symptoms as above....

When I unload and reload the filament, the filament won't come out as smoothly as it used to, it seems (even after my cleaning attempts), and will just 'curl up upon itself', blobbing around the nozzle instead of coming out straight and cleanly....I'm at a loss! Has anybody run into a similar situation to this before?

Any help or suggestions are appreciated! Cheers and thanks!

[Ryan Carlyle]

Curling when loading filament usually means there is some kind of junk in the nozzle. The easy answer is to just replace the nozzle. They're about $5 from QU-BD or ebay. Make sure you preheat the hot end before removing (and reattaching) the nozzle. You'll need an M7 wrench or socket for the nozzle, and something to hold the hot block still.

You can also carefully cook out the PLA with a torch, or possibly dissolve it out with a solvent. Both of these are kinda tricky and easy to screw up, and since you need to remove the nozzle anyway, you might as well just replace it. 

Note, there are lots of other possible causes for extrusion issues, but the fact that this issue includes curling and started suddenly tends to suggest a genuine nozzle clog. It doesn't even have to be something fully jamming the tip, even carbonized junk on the walls of the nozzle will cause this sort of behavior.

[Rob Griesbeck]

I do the stick "something small into the top and push the junk out technique." I take apart the fan and pull the motor off the back, then get a small drill bit, like 1/64 and with the nozzle heated to 230-240, I push the bit down forcing out the left over plastic. It takes a few attempts, but always in the end gets it clean.

Good luck

[Ryan Carlyle]

That works as long as you don't have a BIG chunk of something in there... My last nozzle clog was a 2mm long chunk of aluminum milling swarf.