Clean the print cores

Regular maintenance of the BB print core should be performed once every three months. Using the Ultimaker cleaning filament is the most effective way to clean and unclog the BB print core on the Ultimaker 3. Ultimaker cleaning filament can be found in the Accessory Box of the printer, but if you don’t have the Ultimaker cleaning filament at your disposal, you can use PLA instead.

Cleaning filament can be used to clean the print core on an Ultimaker 3 by applying hot and cold pulls. Hot pulls are used to get the biggest parts of dirt or carbonized material out of the print core and are especially necessary when a print core is clogged. With a cold pull, the remaining small particles will be pulled out, ensuring the print core is completely clean.

Preparation

1. Go to System → Maintenance → PrintCore cleaning to start the cleaning procedure.

   Note: The print head will move to the front right corner itself.

2. Select the print core you want to clean: print core 1 or print core 2.
3. Select the material you would like to use: Ultimaker 3 cleaning filament or PLA filament.
4. Before proceeding to the next step in the printer menu, carefully read the instructions below in order to perform the procedures correctly. Confirm to continue.
5. Wait for the printer to heat up the print core and to retract the filament until its end is visible in the Bowden tube.

   Note: If the material is not retracted, there is a chance that the material has been ground down and it is stuck in the feeder. In this case, remove the material manually as described here.

6. Remove the Bowden tube from the print head. First, remove the clamp clip and then push down on the tube coupling collet while pulling the Bowden tube upwards, out of the print head. Confirm to continue.

Hot pull

1. Insert the filament (Ultimaker 3 cleaning filament or PLA) into the print head until you feel some resistance.
2. Hold the filament with pliers and gently apply pressure to the material for ±1 second so that it extrudes from the nozzle or until it cannot be pushed any further.
   Caution: The use of pliers is required to prevent injuries on your hands in case the filament breaks.
   Note: Applying too much pressure to the filament is almost impossible.
3. Pull the Ultimaker 3 cleaning filament out with a quick, firm pull.
4. Cut off the tip of the filament that you have just pulled out.
5. Check the color and the shape of the tip of the filament and compare it to the image below. The goal is to have a clean tip.
6. Repeat this hot pull procedure until there is no more degraded material visible on the tip of the Ultimaker 3 cleaning filament. The tip of the filament should look as clean as the example on the right.
7. Once the tip of the filament is clean, manually flush some filament through the print core with pliers and take it out again. Confirm to continue.

Cold pull

1. Insert the Ultimaker 3 cleaning filament into the print head by hand until you feel some resistance.
2. Hold the filament with pliers and gently apply pressure to extrude some material. Confirm to continue.
3. Maintain pressure on the filament with the pliers until the progress bar is completed.
4. Release the filament and wait until the print core has cooled down.
5. Grab the filament with pliers and pull it out with a quick, firm pull.
6. Take a look at the tip of the filament and see if it has a clean, cone-shaped tip like shown on the example to the right.

Note: If the tip of the filament is not clean, go back to hot pull or cold pull repeat the cleaning steps.

Re-assembly

1. Re-insert the Bowden tube into the print head and secure with the clamp clip. Confirm to continue.
2. Wait for the Ultimaker 3 to finalize the cleaning procedure.