I am new to 3D printing and bought a Taz4 for my school to use. I have so far been pretty unsuccessful. I did finally get a sucessful ocotpus last friday though!! My prints will start out ok but fail quickly. One problem is that the filament is getting stipped by the hobbed bolt. The question I have right now is that when I extrude filament from a height of 40-50 mm the extrusion doesn’t go straight down but instead will often begin to curl up and stick to the nozzle. I think this is part of my printing problem. Shouldn’t the extrusion drop straight down? If it is, what is causing mine to curl out and what can I do about it?
That curling is normal. it’s the outer layer of the extruded bit cooling faster than the inside, causing it to contract in one direction or another. That should have no impact at all on printing.
You should not be seeing filliament stripping right away. There are several causes of that that you may need to adjust for.
- Nozzle pressure. If you are too close to the bed at start, or if you don’t have the filliament diameter set properly, you can end up extruding too much filliament which will eventually back up the nozzle, causing a blockage that causes the filliament to stop feeding and then strip out. You should take a look at the user manual for the Taz 4, and run the bed calibration gcode until the starting layer looks like the “proper bed adhesion” picture. Make sure all the corners are level and calibrated properly across the entire pass, etc.
Next, check your diameter of filliament with a good set of digital calipers. a 3.00mm filliament is not always 3.00mm. Most common sizes seem to be 2.85mm or 3.12mm actual diameter that I see anyways. The hot end will accomodate those other sizes just fine mechanically, but the slicer settings itself need to be adjusted so that you are actually extruding the amount of plastic you think you are. If the settings are currently set to 3.00mm and you actually are feeding 3.12mm, the back pressure will build up quickly and cause the filliament to block and then strip out. Adjust the filliament settings in slic3r accordingly.
Finally, check the hobbed bolt chamber itself. You should remove any loose shavings, clean any plastic out of the teeth of the hobbed bolt itself, remove any other residue, then set the spring tension according to the manual. Too tight can cause filliament stripping, though it can also just show signs of the back pressure problem sooner than a loose bolt would
- Electrical. It is possible that your heater cartridge or thermistor are not working properly. That is rare, but can happen with these devices. If checking out the nozzle pressure settings does not fix the issue, you may want to grab an inexpensive point and shoot infrared thermometer and check that the heat settings match the actual heat output. For ABS the nozzle should be around 230 degrees C. The bed should be 85C
Thanks a bunch. I took the nozzle off yesterday and soaked it in acetone and it seems to be working better today. I spent a great deal of time this morning leveling the bed, I think I have it closer to what it needs to be, because it is currently printing something. Turns out the filament was 2.77mm and I was using the lulzbot abs Slic3r config which had 2.85. I believe the stripping was due to it being to close to the bed. Thanks for the help!