How to apply the Atomic Method?

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The Atomic Method can be used to unclog the nozzle of your Ultimaker. It will clear the blockage by pulling dirt or carbonized material out of the nozzle from the top side. To apply the Atomic Method you don’t need to disassemble the print head or hot end, which makes it very easy to use this method.

Tip: Besides using this method to unclog the nozzle, you can use the Atomic Method when switching to a material that requires a lower printing temperature. This way all residue from the previous material will be removed, helping to prevent blockages.

The steps below describe how to apply the Atomic Method. The videos show the Atomic Method applied to the Ultimaker 2+, but this method can be used on all Ultimaker 3D printers, except the Ultimaker 3 (Extended). If you have an Ultimaker 3 or Ultimaker 3 Extended, take a look at the guide on how to clean the print core.

Note: Make sure you move the print head to a corner of your Ultimaker to prevent bending the axles.

Removing the material

Remove the material from your Ultimaker.

  • On an Ultimaker 2(+) go to ‘Material’ → ‘Change’ and select ‘Cancel’ after you have removed the material.
  • If you have an Ultimaker Original(+), you go to ‘Control’ → ‘Temperature’ → ‘Nozzle’ and set the temperature, after which you can remove the material.


Removing the bowden tube

  1. Remove the clamp clip that is placed around the bowden tube on top of the print head.
  2. Press down the tube coupling collet and pull the bowden tube out of the print head.


Heating up and preparing

Heat the nozzle of your Ultimaker to the temperature of your last used material.

  • On the Ultimaker 2(+) you go to ‘Maintenance’ → ‘Advanced’ → ‘Heatup nozzle’
  • On the Ultimaker Original(+), manually heat up the nozzle via the ‘Control’ menu

  1. Cut off approximately 20 cm of filament (of your last used material) with a straight cut and try to straighten it as much as possible.
  2. Wait until the nozzle has heated up and then insert the piece of material in the print head, all the way down into the nozzle.
  3. Push the material slightly until it either comes out of the nozzle or cannot be pushed any further.


Removing the material

  1. Lower the temperature to 90° C for PLA. For ABS you will need 110° C.
  2. Wait until the temperature is reached and then pull the material out with a quick, firm pull.
  3. Check the color and shape of the tip of the filament. The goal is to have a clean, cone-shaped tip.
  4. Repeat the steps ‘Heating up and preparing’ and ‘Removing the material’ until the filament comes out without any residue and has a cone-shaped tip.

Note: It is important to pull the material out quickly. If you pull it out too slow, the filament will stretch.



  1. Insert the bowden tube in the print head, all the way down into the white coupler.
  2. Place the clamp clip around the tube coupling collet, so that the bowden tube is secured.


If you're in need of even more tips, check out our 'how to unclog an Ultimaker nozzle' guide.