The front fan cools the print cores during a print. This helps to prevent the heat from the nozzle from traveling too far upwards.
The fan takes in air from the front of the print head and directs it towards the print cores. Sometimes the airflow causes thin strands of filament to be sucked into the fan during a print. If strands accumulate in the fan, they can decrease the effective cooling and eventually obstruct the fan and prevent it from spinning. Especially high-temperature materials, such as CPE+, PC, and ABS are prone to this.
If the front fan does not spin during printing, this can quickly lead to extrusion problems and obstructions in the print core. Never start a print job if the front fan is not functioning.
To prevent problems with this fan, it is recommended to check and clean it every three months. When you print a lot, and especially with the materials listed above, it is recommended to increase the cleaning frequency.
Caution: Make sure that the print cores have completely cooled down before starting this maintenance action. Turn off the printer or ensure it is disabled in the Ultimaker Digital Factory to prevent new print jobs from starting remotely.
To check the front fan, first gently open the front fan bracket. Blow into the front fan to see if it spins smoothly. If it does not move at all or stops spinning abruptly, you will likely see strands of filament stuck in the fan. Use tweezers to carefully clear any obstructions from the front fan from the inside.
Tip: This is possible with the print cores in place, but you can also remove the print cores first for easier access.
Next, close the fan bracket and check the fan from the outside. Remove any strands from that side too.
After removing all visible filament strands from the fan, check again if it spins. Via the menu, raise the temperature of one of the print cores. The front fan will be activated if one of the print cores reaches a temperature of 40 ºC or higher. If the fan does not spin, it should be replaced. Please reach out to support or contact your local reseller for a replacement.
Note: This only affects the front fan and not the side fans of the print head. The radial side fans take in air from the top and are much less likely to get blocked. The side fans will only spin during printing to cool the model.