Just got my hands on a gently used Flashforge Dreamer. The printer is on loan to Maui Makers to print some prosthetic hands from eNABLE for some kids on Maui. Since I'd never used this particular model, first order of business was to get the printer up and running with a test print.

And, the right extruder jammed!

Documentation and visual inspection confirmed this was an MK8, similar to my Makerbot Replicator 2 and Prusa i3. These are really straightforward to unjam.

Step 1: Remove the Fan

There are two bolts in the bottom of the fan. Remove them with the supplied allen wrenches. Be careful once you get the bolts loose, because they hold everything together.

Step 2: Remove Filament From the Delrin Plunger

In some cases, the filament has slipped in the drive mechanism for the Delrin Plunger. Delrin is simply the type of plastic used to make the device, and plunger refers to the fact that it "plunges" or pushes filament into the hot nozzle.

The stepper motor moves has a hobbed (with teeth) gear (see second photo). This grabs onto the filament and pushes it down into the hot nozzle. Over time you may get small bits of filament that fill up the teeth. This will make the gear slip and you'll get a jam. Another issue is when you don't get the filament loaded all the way down into the hot end. This can cause the filament to wind around the gear rather than going down into the nozzle. In either case, you'll get a jam.

You'll need to remove the bolt that holds the top arm on to get to the teeth and clean them with a toothbrush or compressed air. To remove this lever, you've got to worry about two things: 1) the spring under tension--don't loose it; and 2) a metal insert in the bolt hole you just removed. You'll need to pull the metal insert and then tilt the lever towards you to relieve pressure on the spring. Just work slowly.

If the filament is jammed further down, you'll need to remove the rest of the plunger using the small bolt on the top.

Slowly and carefully cut away any gummed up filament with wire cutters, and clean out any plastic flakes that are in the hobbed gear.

If the filament is jammed further down, you'll need to remove the rest of the plunger using the small bolt on the top.

There is an aluminum block with a hole at the top below the plunger. If you can, you want to leave some filament sticking out of this block for the next step.

Step 3: Remove Filament Clogged in the Hot End

This is the tricky part.

Turn on the machine and select the "load" or "unload" filament option. It doesn't matter which one, since you don't have the stepper motor attached.

Wait until the extruder reaches full temperature. Be cautious because the fan will run and the stepper motor will turn. Keep fingers, hair, dangly things and tools clear of them.

If you have filament poking out of the hole in the top of the aluminum block, you are lucky. Grab some pliers and slowly, but firmly pull up on this filament. If you are lucky, you will pull out the clog and be good to go.

If not, move on to the next step.

Step 4: Using Filament to Remove the Blockage

You now want to test that there isn't anything else blocking the nozzle. You can do this by acting as your own "plunger". Take your filament and carefully shove it into the hole into the nozzle through the feed holes. If everything is good, then you'll see filament streaming out the bottom.

Once you're happy that it's extruding well, pull the filament back out and move on to the next step.

Step 5: Put Everything Back Together in Reverse Order

We finally decided to remove the motor to make it easier to get everything bolted back together. But it can be done either way. And we're using the printer top as a handy parts holder (after spending 20 minutes looking for the spring, we decided to make sure nothing escaped.

It is somewhat difficult to get the bolts aligned with the holes on the stepper motor. Be careful not to strip the bolt holes on the stepper motor.