Every so often, you might find your prints are looking stringy, sparse, and with missing layers. If you check through our 3D printer troubleshooting guide, you'd figure out your nozzle is more than likely clogged. No worries - this guide will help you solve the issue and get you printing again in no time. 

What Causes 3D Printer Nozzle Clogs

To understand a clog, it's probably best to know a few things that can cause the issue in the first place. Keeping filament sealed up and clean is a good practice to help avoid clogs. 

  • Filament stripping in the extruder gear and the filament left in the nozzle solidifies into a plug
  • Dust on dirty filament forms a plug
  • Something as simple as not cleaning out the nozzle after changing between materials

How To Check if Your 3D Printer Nozzle is Clogged

Disengage the extruder gear lever and push filament through by hand. If it curls, is hard to push through, or doesn’t come through at all, the nozzle is clogged. It doesn’t take much force to get it through, so don’t press on it too hard.

Tools Needed to Unclog Your 3D Printer's Nozzle

If you are using all the methods to unclog your nozzle below, you will need the following tools. We recommend trying them all and finding one that works best for you. 

  • Cleaning filament or nylon filament in the diameter your printer uses.
  • A brass wire brush (steel wire can damage the nozzle)
  • Acetone
  • Acupuncture needle
  • Crescent wrench
  • Socket wrench
  • Heat gun or blowtorch

Checking the force needed to push filament through the nozzle.


Method One: Brass Wire Brushing

Using a brass wire brush, clean off any debris from the nozzle. Make sure that you use a brass wire brush - do NOT use a steel wire brush, as it can cause damage to the nozzle. 

Using a brass brush to clean off a nozzle.


Method Two: Acupuncture Needle

  • Preheat your printer to the print temperature of the last material you were printing with. 
  • Gently and carefully insert the acupuncture needle up through the nozzle.
  • You aren’t trying to remove the particles, just break them up so they extrude the next time you extrude filament.

Using an acupuncture needle to break up a blockage.


Method Three: "Cold Pull" With Nylon or Cleaning Filament

  • To do a “cold pull” use Cleaning Filament or Nylon Filament in the same diameter filament that you normally print with.
  • Heat up the nozzle to 250°C and push the filament through the nozzle until you don’t see any of the previous filament coming out of the hotend.
  • Cool down your extruder to room temperature to solidify the filament in the nozzle.
  • Set the hotend to 115°C.
  • At 90°C, pull on the filament until it yanks out of the nozzle. This should leave the shape of the inside of your nozzle on the end of the filament. You should be able to see the particle in it.
  • Again, heat up the nozzle to 250°C and push the filament through until it comes out clean and easy.

Pulling out cold nylon to clear the nozzle.


Method Four: Removing the Nozzle

  • Heat up the nozzle to the print temperature of the last material you used.
  • Use a crescent wrench to hold onto the heater block, while you use the socket wrench to twist off the nozzle.
  • Be careful not to touch any of the hot parts, it’s really easy to slip and burn yourself.
  • With the nozzle removed, use chemicals to dissolve the filament and wash out the clog, or use heat to burn it out.
  • If your printer clogged after using ABS, simply drop it in a container of acetone and the ABS will dissolve away.
  • There are chemicals you can use for other materials, but they tend to be more caustic or hard to find. In those cases, a heat gun or blowtorch (using the proper safety precautions) can melt out the remaining filament.
  • With a heat gun or blowtorch, wave the heat over the nozzle like blow drying your hair; direct heat from a blowtorch can actually melt your nozzle.

Place the nozzle into acetone to remove ABS filament clogs

 


Carefully using the heat gun to remove clogged filament

 


As you can see, there are quite a few good ways to fix a clogged nozzle. Find the right way that works for you, and keep on printing.