FDM — Nozzle Jammed

What’s the issue?

Filament is fed to the nozzle well, and the extruder is working, but no plastic comes out of the nozzle, retracting and re-feeding doesn’t work. Then it is likely that the nozzle is jammed. 

Possible causes

—Nozzle Temperature

—Old Filament Left Inside

—Nozzle Not Clean

Troubleshooting tips

—Nozzle Temperature

Filament only melts at the range of its printing temperature, it cannot be extruded if the nozzle temperature is not high enough.

Check the printing temperature of the filament and check if the nozzle is getting hot and to the correct temperature. If nozzle temperature is too low, increase the temperature. If the filament is still not coming out nor flowing well, increase 5-10 °C so that it flows easier.

—Old Filament Left Inside

Old filament has been left inside the nozzle after changing filament, because the filament has snapped off at the end or melt filament hasn’t been retracted. The left old filament jams the nozzle and doesn’t allow the new filament to come out.

Increase nozzle temperature

After changing filament, the melting point of the old filament may higher than the new one. If the nozzle temperature is set according to the new filament, the old filament left inside will not melt but cause a nozzle jam. Increase the nozzle temperature to clean the nozzle.

Push old filament through

Start by removing the filament and the feeding tube, then heat up the nozzle to the melting point of the old filament. Manually feed the new filament directly to the extruder, and push with some force to make the old filament comes out. When the old filament completely comes out, retract the new filament and cut the melted or damaged end. Then set up the feeding tube again, and re-feed the new filament as normal.

Clean with a pin

Start by removing the filament. Then heat up the nozzle to the melting point of the old filament. Once the nozzle reaches the correct temperature, use a pin or something else that smaller than the nozzle to clear the hole. Be careful not to touch the nozzle and get burn.

Dismantle to clean the nozzle

In extreme cases when the nozzle is heavily jammed, you’ll need to dismantle the extruder to clean it up. If you’ve never done this before, please check the manual carefully or contact us to see how to do it right before you proceed in case of any damage.

—Nozzle Not Clean

The nozzle might easily to get jammed by many reasons if the printer has been used many times, such as unexpected contaminants in the filament (with good quality filament this is very unlikely), excessive dust or pet hair on the filament, burnt filament or residue of filament with a higher melting point than what you’re currently using. The jam material left in the nozzle will cause printing defects, such as small nicks in the outer walls, small flecks of dark filament or small changes in print quality between models, and eventually jam the nozzle.

Use high quality filaments

Cheap filaments are made of recycle materials or materials with low purity, which contain a lot of impurities that often cause nozzle jams. Use high quality filaments can effectively avoid nozzle jams cause by impurities.

Cold pull cleaning

This technique feed the filament to the heated nozzle and have it melt. Then cool down the filament and pull it out, the impurities will come out with the filament. Details are as follows:

Prepare a filament with higher melting point, such as ABS or PA (Nylon).

Remove the filament already in the nozzle and the feeding tube. You will need to manually feed the filament later.

Increase the nozzle temperature to the printing temperature of the prepared filament. For example, printing temperature of ABS is 220-250°C, you can increase to 240°C. Wait for 5 minutes.

Slowly push the filament to the nozzle until it starts to come out. Pull it back slightly and push it back through again until it starts to come out.

Reduce the temperature to a point that below the melting point of the filament. For ABS, 180°C may work, you need to experiment a little for your filament. Then wait for 5 minutes.

Pull out the filament from the nozzle. You will see that at the end of the filament, there are some black materials or impurities. If it is hard to pull out the filament, you can increase the temperature slightly.

Date:2022-8-30 Author:admin