UNJAMMING A NOZZLE

A jammed nozzle is one of the most infuriating issues with any 3D printer. The most common reasons for this are that a cheap filament has been used, and the consistency of the material is out. This results in the gears that feed the filament through the system slipping, which will ultimately cause the filament to wear. Cheaper filament can vary in diameter, again causing the gears to slip or the nozzle to be at the incorrect heat for the filament to flows through evenly.

Another issue can be that the material has degraded. It may have been open for a while and become brittle or absorbed moisture. When filament becomes brittle, it can break at any point, but that point is often just after it’s entered the extruder gearing. The pressure of the gears on the filament is enough to cause a break, and often requires a little dismantling of the tool head to clear the problem.

Finally, the worst blockage is often caused by expanding filament. This happens when the filament has absorbed moisture, and as it enters the hot end it expands and blocks. First unload the filament and check the position of the filament’s end. If you see it sticking out of the extruder, preheat the nozzle and try using tweezers to extract the filament. If this doesn’t work, take another length of filament, preheat the nozzle to the maximum filament temperature, and push the new filament in, hopefully unblocking the nozzle. You can buy thick metal needles for this same job.

If that still fails then try the hot and cold pull methods. Hot pull involves heating the nozzle, pushing the filament in until you feel resistance for a second or two, then pulling it quickly out, cutting off the end and repeating until you see filament extrude from the nozzle.

The cold pull is much the same: heat the nozzle, insert the filament, let the nozzle cool slightly, and then pull.

Another popular option is to use a fine needle. Insert the needle from the outside; you’ll need to heat the nozzle to melt the filament inside.