Applying the hot and cold pull method on the Ultimaker 2+ Connect

Cleaning the nozzle of your Ultimaker 2+ Connect can improve your printing results. When dirt or carbonized material accumulates inside the nozzle, you may have extrusion problems, or these burnt parts can show in your printed model.

There is a simple process for cleaning the inside of the nozzle that does not require disassembly of the print head. You will only need to remove the Bowden tube. This is called the hot and cold pull method. You can use cleaning filament or PLA for this.

The cleaning process is split into two steps: hot and cold pulls. Hot pulls are used to get the biggest parts of degraded material out of the nozzle and are especially necessary when the nozzle is clogged. With a cold pull, the remaining small particles will be pulled out, ensuring the nozzle is completely clean.

Tip: A cold pull is also recommended when switching to a different material type or when changing the nozzle.

Caution: This procedure requires heating up the nozzle. Be careful and do not touch the nozzle. Protective (thermal) gloves are advised. During this procedure, use pliers to hold the material to prevent injury to your hands in case the material breaks. Ensure the Ultimaker 2+ Connect is disconnected from the Digital Factory or made unavailable for new print jobs.

Preparation Hot pull Cold pull Reassembly
1. Unload material Remove the material from the printer. In the Materials menu, select Unload. Wait for the nozzle to heat up, open the feeder, and pull back the filament.
2. Place print head Manually place the print head in the front-right corner of the printer. This gives you easy access to the print head and prevents damage to the print head shafts.
3. Remove Bowden tube Remove the clamp clip from the print head. Push down on the white tube coupling collet and pull the Bowden tube up and out of the print head.
4. Prepare cleaning filament Take one piece of Ultimaker cleaning filament. If you do not have this available, cut off a length of filament, approximately 20 cm. You can use PLA for this, but other (non-flexible) materials will also work.
5. Heat up nozzle In the Maintenance menu, select Set nozzle temperature. When using cleaning filament, increase the temperature to 260 ºC. For PLA, choose 235 ºC. Wait for the nozzle to heat up.


The nozzle is now clean again on the inside for optimal extrusion. If you have any questions about this process, or when you continue to experience extrusion problems with your Ultimaker 2+ Connect, contact support by submitting a ticket.

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