A jammed hot end is a common problem with 3D printing, and can even occur during a print. This is usually catastrophic, but can easily be remedied, and with a little bit of care, can usually be avoided.
The hot end of the EVO “air printing” above a part after a filament jam.
Priming the hot end.
First, check to make sure you are using the correct settings for the filament that is loaded into the machine. If the incorrect temperature is used, jams can and will most likely occur.
Select the correct filament within APEX.
Second, always check your nozzle and do preventative maintenance if needed. This includes cleaning the brass brush of filament debris, cleaning the nozzle itself, or completely swapping a worn-out nozzle for a new one. It’s a good idea to change nozzles every 200 hours.
Make sure to remove debris stuck in the brass brush before printing.
Power the machine off and clean the nozzle with a wire brush.
A worn nozzle can cause filament jams and should be replaced.
Third, check the filament. If your filament is too thin or too large in diameter, jams will occur. If you suspect the filament is the issue, cut off the thick piece and reload, or change the roll altogether. Old filament, especially nylon, can swell over time due to an increased presence of moisture.
If the filament diameter is too thick or too thin, jams will most likely occur.
Fourth, check the feeder area of the hot end to make sure there isn’t any debris stuck in the drive system. Check this area periodically.
The feeders should be checked periodically for filament debris.
If you experience a filament jam, there are some simple procedures you can follow to get you going again.
Preheat the hot end 20 degrees higher than the preheat temperature. Remove the filament, cut it at a 45-degree angle, and re-feed. Press PRIME several times to try and clear the hot end. If this didn’t work, remove the filament, and move on to the next step.
Preheat the nozzle to a higher temperature. This will help remove the filament if it is stuck in the hot end.
The PRIME button will slowly push filament through the hot end.
If a higher temperature did not remedy the issue, inspect the nozzle. If the nozzle appears worn down, is rounded, and has a deformed orifice, it needs to be replaced.
These two nozzles are rounded at the tips and the orifices have been closed off due to deformed metal.
New nozzles are easy to install on the EVO hot end.
If the filament jam is occurring during a print, check the first layer height carefully. If the first layer is too close to the build plate, it will cause the hot end to jam, and the print will fail. Simply adjust your Z Offset further away from the build plate on the first layer.
This image shows the nozzle too close to the bed during the first layer. This will cause premature nozzle wear and will most likely cause the filament to jam.
*Version 1.65 of the touchscreen allows the user to adjust the first layer height without installing new firmware.