Failed print Help
First, I just pit this together and I think it's great so far. I've spent about three nights printing various calibration tests (the v2, the 750mm flat square, etc) and I think I finally have the Live-Z calibration where it needs to be. I've printed the Prusa logo a couple times, came out fine. I printed the little dog that came on the demo SD card, also fine. I managed to slice a USB cable holder off of Thingiverse and, after some testing with the settings I got two perfect prints one after the other (My wife saw mine and wanted one).
That said, every time I have left the printer to try something larger like the castle or the dragon it goes for several hours then I notice some slight stringing, then either the nozzle clogs or the filament stops, or something weird. I have yet to figure it out. I thought things were looking good after spending a couple days re-calibrating, but the castle failed just before it got to the spires and the dragon failed just at the tip of the tail (see pictures). Usually, to get things working again after a failed print I have to force a "load filament" procedure and press down on the filament because it's been stripped at the feeding gear. Is it possible to get the tension screws too tight? if they are more loose then it won't feed on the smaller prints so I think it's OK where it is.
I'm still having fun, but I want to know what direction I should be going in here or some suggestions at least. I feel like I'm expending a really large amount of filament figuring all this out.
Re: Failed print Help
3 more pictures
Re: Failed print Help
Have you calibrated your extruder? (Read this if not: http://shop.prusa3d.com/forum/prusa-i3-kit-building-calibrating-first-print-main-f6/extruder-calibration-t2033.html )
It seems that your underextruding. So two possibilities: too much underextruding or something get in the way of the extruder. What is the length of your extruder springs? They sould be at 13mm with filament inside.
Re: Failed print Help
I did not know about the 13mm spring measurement, I don't remember seeing that in the instructions, but it is worth a shot. In addition I don't remember reading anything telling me to calibrate the feed speed.. I will have to give that a shot as well.
I had a similar thought about the spring tension, so I backed out the screws by 1.5 - 2 turns each and increased the filament temperature by 10 degrees (set to 225 instead of the 215 all the example prints seemed to be set to). I did this with the thought that possibly the height from the bed was causing there to be less heat. Under this line of thinking I was going to build an enclosure thinking it might be a heat issue. Only making those two changes I got the results shown below (sooo close!!!) but it still had some things that made me question if it was right anyway. The back of the wings felt like a serrated knife and there were lots of fine stringy filament near the failure point.
Thank you for the advice, I'm willing to give it a shot. At this point if someone said I needed to kill a chicken as an offering to the Gods of 3D printing before each run I'd consider it.
Re: Failed print Help
That spring setting was key! I had them down to around 9mm, when I backed them off to 13mm printing started going WAY better. Thanks for the help!