Possible grinding problem for extrusion issue? Need help determining cause.

[dylanweber 0]

I currently own a kit-made Ultimaker that I've had for over a year now. I have only used the original PLA plastic spool that came with the printer. Just last week I bought the heated bed upgrade kit and now I currently have a functioning Ultimaker Original with a heated bed. Since then, I've been printing a lot of objects for my engineering class, but I've noticed that there was a tiny under extrusion, but I shrugged it off since the general shape of the object is all I was aiming for.

Beginning yesterday, the under extrusion got worse. The gaps on the walls got much more noticeably bigger. I decided to try to manually push the plastic into the extruder at 214 degrees to see if it was clogged... it was difficult to push but plastic came through. I'm not sure how hard it should have been so I tried cleaning the extruder using the atomic method. After heating to 260 degrees, plastic pushed through the extrusion head very very easily. Once cooled to 90, I couldn't get it to pull out in a perfect arrow tip but no carbonized material was coming out with the plastic. I repeated the cleaning 4 times. After that, the printer was printing fine for a short while. I was able to print a 12.5 cm cube without any noticeable issues.

Prints afterward were worse. My first print after the cube stopped mid-way because the temperature sensor wires fell out. From what was already finished, the result still had gaps in the walls. After reattaching the wires and attempting to reprint multiple times, I couldn't even get the first layer to print on a well-leveled bed without extreme under extrusion. Further looking into the issue, I believe it is the extrusion mechanism that pushes the plastic into the bowden tube. It's been pushing holes into the plastic a bit more than it normally used to. It maybe slipped once or twice in the past day. My bowden tube has also seen some tough love with pliers in the past. Could the bowden tube have too much internal friction? Could the tension on the extruder be the source of all my issues? How hard should it be to push the plastic into the extrusion head manually with my hands?

Edited May 9, 2016 by Guest