Quote Originally Posted by dunginhawk View Post
So its basically about 7 inches across at the bottom and it tapers at the top, its a cone essentially. it fails about 6 inches up. its failed at lik4 -6inches up.
Well, it just failed on a short print too, so something is going on. It is NOT the bed.. I can guarantee that.. the PEI surface im using is VERY good and i have to peel these things up with a putty knife. they are wicked sticky

I may clean out the nozzle and run some cleaning filament through it, or heat it up to 270 and just flush some cleaning filament through it. other than a partially clogged nozzle, i dont know what else it could be at this point. Unless this filament is bad (2 spools in a row) perhaps its diamter is bad but i dont think that is as likely.
I can't tell you how many times I ran into this problem in the first two months of printing...hundreds would be my guess. In the end I traced my fundimental problem down to a dirty nozzle. That doesn't mean I didn't address other issues along the way like the hob-bolt and extruder block being designed for 3mm and not 1.75. I redesigned both, printed a new extruder block with the right size hole and made a new hob-bolt to fit the smaller filament. One day while I was cleaning the extruder I found a small hang-up between the nozzle and filament guide right where they meet in the heater block, chamfering the leading edge of the nozzle fixed that one.

But like I said I eventually tracked down the real culprit and that was a few very small bits of PLA that I had used on my initial test run before switching to ABS. The higher heats needed for ABS carmelized (for lack of a better word) that PLA against the inside of the nozzle causing the majority of my air prints. It took a lot of soaking and cleaning to remove those little bits of burnt plastic, but I was rewarded with weeks and months of flawless printing afterwards. Now I periodically test my nozzle by pushing a piece of filament through by hand...anything other then a smooth easy extrusion means it's time to clean. Oh and I'll never run PLA and ABS through the same nozzle again!

Mike