4 things i can think of would be:
1. To low speed, so nozzle pressure get close to zero. Try tp up your speed. (I print 30mm/s first layer and 70mm/s for the rest on a Mendel90)
2. To much play (backlash) in your extruder gears, so you get a delay.
3. To high firmware acceleration, my xy acceleration is 1500 and 3000 for non printing moves. To high acceleration, can stretch you filament path when getting up to speed.
4. 0.3 layer height is a bit to much with a 0.4 nozzle (but that's only a bondig problem), try 0.25 or lower.
Hope it help you
Jesper
Edited 1 time(s). Last edit at 12/12/2013 02:50AM by Kenzu.