Two issues that were causing intermittent problems were:
- The Teflon tube on the bowden occassionally working its way loose during a print.
This was a pain. If I tightened the clamp up too tight it would crimp the tube and restrict the path of the plastic filament. I tried a few things like filing the outside of the tube to provide more grip, adding some tape, etc.
Finally I had a eureka moment when I suddenly woke up at 3am Saturday moning. I Then couldnt sleep, so I got up to try and implement the idea. I added a threaded nut onto the Teflon tube and redid the connection so the night is locked inside and cannot pull out. Success
- The extruder sometimes skipped when feeding filament during parts of the print that involved laying alot of plastic quickly. Basically did not have enough torque. I redesigned the gears shrinking the drive gear a little and increasing the size of the secondary gear to increase torque.
This last print was at .2mm layer height abd too about 4 hours. I had to vary the speed at certain points to allow the filament to dry on the smaller diameter parts