Makerbot down! We have a makerbot down!

I’ve only had the makerbot for a month now, but it’s refusing to print. Sigh. I know it’s a diy kit, but this little puppy only had three whistles printed on it before it rolled over, ready to die. Here is my thought process as I go about trying to fix it.

Symptoms: The extruder would no longer extrude. RepG registers 220 and the hot end seems to settle nicely there. The motor turns on but nothing comes out. I have a mk4 extruder and was in the process of printing a wade’s extruder when the symptoms started (do you think it got jealous?) If I grabbed the filament with pliers then I could push plastic out the tip, but it also squeezed out between the pfte insulator and the brass barrel.

My Diagnosis: After adjusting and re-adjusting the difficult pressure wheel on the mk4 I settled on the idea that the tip must be partially blocked or not hot enough. I took it apart and broke the brass barrel in two. Then I made a new barrel out of a bolt and bought a new barrel (two path approach!)

Here you can see that the nichrome wire has burned/melted the kapton tape. Is that normal?

None good. The stock barrel behaved exactly the same. It would flow, but weakly and only with considerable pushing on my end. The new hot end I made fared about as poorly. I tried to re-use the nichrome wire from the original hot end build, but at some point it had burned off its coating and this was very problematic.

Next steps:
1 – rebuild stock barrel/ptfe combo
2 – test resistance of nichrome on new barrel
3 – buy and build wades extruder
4 – use both extruders on mk4 setup to see if it is the hot end, then swap in the wades extruder to see if it is the motor.