Sometimes filament can get jammed in the hot end of your 3D printer. While this is very annoying it happens to most 3D

Remove fans printers from time to time.

Symptoms

It is likely that you have a filament jam if;

  • You hear ticking noises coming from the stepper motor that pulls the filament down.

  • The filament only pushes down so far and then stops suddenly.

  • When you unload filament and look at it closely there is a notch or ground out part on the filament

Method

In the case of a jam you have to remove the filament that is causing the jam. There are a few different places where jams may occur in the extruder. It can be at the top just below the extruder gear and just above the thermal barrier, in the PTF liner or at the nozzle. Each of these areas require a different approach.

Above the thermal barrier

This is a common place for a jam and is relatively quick to fix. It involves dissembling the print head a little, if you would like a video to see the process there is a full disassembly video from Flashforge USA detailing the process, it can be found here. You do not have to completely dissemble the print head for this fix however.

  1. Remove the screws from the fan at the front of the print head. You only need to remove the screws for whichever extruder has the jam.

  2. Move the fan out of the way then proceed to remove the heat sink from behind the fan, there will also be two little plastic spacers, make sure you hold onto them

  3. Now you should be able to see the extruder gear, unplug the stepper motor by removing the electrical cables at the top of the stepper motor.

  4. Push down on the plunger and move the stepper motor out of the way. We push down on the plunger so if there is any filament still in the extruder gear we can remove the stepper motor easily.

  5. Look at the extruder gear if there is any plastic build up on the gear you may wish to clean it out using a small paint brush. You may wish to remove the plastic plunger if you have a lot of build up, be careful of the spring when you are removing the plunger.

  6. You should be able to see if the any plastic is stuck at the top of the thermal barrier, usually the plastic will have a bit of a bulge around the entrance if this is the case. Using some tweezers or fine nosed pliers and pull the filament out.

  7. Re-assemble printer, run test print to be sure that the blockage has been cleared.

In the PTFE liner

Blocked Liner

The PTFE liner is a tube inside the thermal barrier and runs all the way down to the nozzle. Blockages sometimes occur in this area and can be caused by the liner wearing over time. The PTFE liner should be considered a consumable and replaced.

  1. Get a large shifter and fasten it to the heat block. We will be using this to make sure out hot end does not rotate at all.

  2. Using a socket wrench we want to unscrew the nozzle from the heat block. You may wish to hold the shifter while doing this to make sure there is no rotation.

  3. Once the nozzle is unscrewed the liner normally will come out with it, if not use some tweezers to gently pull the liner out. If you still have a length of filament in the hotend you will need to press down on the plunger while you pull the liner out.

  4. Replace with a new liner, you get some in your tool kit when you purchase a Flashforge dreamer. You can purchase additional replacements from our site.

  5. screw nozzle with liner back into the heat block, again be very careful not to rotate the hot end while screwing the nozzle in. The nozzle should be in fairly tightly to make sure that the liner is held in place firmly.

  6. Run a test print.

In the nozzle

Sometimes a blockage can be just at the very tip of the hotend and depending on the severity can require different methods to remove. For the simplest of blockages you will need a fine nozzle cleaning spring we do sell such a device

which you can find here here.

  1. Run a pre-heat on the nozzle that is blocked. This can be done by turning your printer on and pressing the preheat button then setting the temperature of the appropriate extruder.

  2. Once the hot end is up to temp you can use the nozzle cleaning spring to poke up the nozzle and dislodge the jam. If you are able to

    successfully poke the wire into the nozzle you have either dislodged the blockage or the blockage is further up the hotend and will need to read the previous instructions on how to remove the blockage.

  3. If you were unable to get the nozzle cleaning spring into nozzle you may require more serious cleaning like using a copper brush to clean the surface of the nozzle then try again with the nozzle cleaning spring.

  4. If the previous steps have not worked you should remove the nozzle and attempt further cleaning. 

  5. To remove the nozzle, get a large shifter and fasten it to the heat block. We will be using this to make sure out hot end does not rotate at all.

  1. Using a socket wrench we want to unscrew the nozzle from the heat block. You may wish to hold the shifter while doing this to make sure there is no rotation.

  2. Once the nozzle is unscrewed the liner normally will come out with it. Separate the liner from the nozzl by simply pulling them apart.

  3. Use the nozzle cleaning spring to try and push the blockage from the other side. If this is unsuccessful you may wish to soak your nozzle in acetone overnight and try again. This method is most successful for those that use ABS

    as their printing medium.

  4. If all of the above steps have not worked you may need to purchase a new nozzle.



Bilby3D hopes you find this helpful.

Please call 1800-847-333 if you need further assistance.

Happy printing!