Sometimes your extruder will stop extruding and you'll need to align the hot-end with the cold-end.
The following is the procedure to align the filament path in the extruder:
Loosen the two screws in the back of the extruder, when these screws are loose it give you the ability to move the hot-end left or right to align in the x-direction.
Loosen the six screws that attach the cold-end to the x-axis carriage assembly. With these six screws loose, you then adjust the alignment of the filament path from the cold-end to the hot-end in the y-direction.
Straighten a piece of filament to use as a guide for this step of the alignment procedure. Remove the wing-nut, spring and washers on the filament tensioner arm and swing the arm all the way open. Insert the straightened piece of filament into the filament opening and slowly lower it into the opening of the hot-end. As the filament approaches the hot-end opening, either visually check the alignment or "feel" for any resistance.
Once you have the filament path aligned between the hot-end and cold-end. Tighten down all the screws loosened in steps #1 and #2. With the filament path aligned correctly, there will be less resistance and friction during extrusion and it be less likely for PLA extrusion problems. ABS is more forgiving, but still benefits from this alignment procedure.
Other possible causes for PLA extrusion issues
- Cooling fan has stopped working -- The hot-end barrel is actively cooled using a 40mm fan. If this fan stops functioning, it only takes a few minutes before your extruder will jam and stop. Replacement of the failed fan is the only solution to this problem.
- Partially clogged nozzle -- A partially clogged nozzle will also cause too much resistance and lead to extrusion issues with both PLA and ABS. Sometimes running ABS filament thru will clear out PLA jams or manually extruding filament until the partial clog is cleared. Its also possible to use a very small wire or 0.4mm drill bit to clear the partial clog. With the hot-end heated up, raise the extruder about 3 or 4 inches above the build plate, push the wire or drill up into the nozzle opening. Repeat until the partial clog is cleared.
- Too small first layer gap or improperly tuned z-axis steps_per_mm -- If the first layer gap is too small, the nozzle opening will be blocked during extrusion causing the same condition as the partially clogged nozzle and cause extrusion issues. Increasing the first layer gap will first this issue. Improper z-axis_steps_per_mm settings could also cause each layer to be smaller than assumed, which blocks the nozzle during extrusion and causing extrusion issues. Update the firmware and check the z-axis steps_per_mm setting to fix the issue.
- Poor or cheap filament -- Sometimes cheaply made filament can cause extrusion issues. Change out the filament to a different brand to see if this is the problem.