A part cooling fan helps to cool down the extruded filament and improve the print quality. However, sometimes the fan may stop working or malfunction, causing various problems such as warping, stringing, or poor surface finish. I want to show you how to troubleshoot 3D printer part cooling fans and fix some common issues.

The first thing you need to do is to check if the fan is spinning at all. You can do this by turning on your 3D printer and looking at the fan. If the fan is not spinning, there may be a problem with the power supply, the wiring, or the fan itself. To test the power supply, you can use a multimeter to measure the voltage across the fan terminals. The voltage should be around 12V or 24V, depending on your printer model. If the voltage is too low or too high, you may need to replace the power supply or adjust the voltage regulator.

If the power supply is fine, you can check the wiring for any loose connections, broken wires, or short circuits. You can use a continuity tester to check if there is a complete circuit between the fan terminals and the power supply. If there is no continuity, you may need to solder or replace the wires. If there is continuity, but the fan still does not spin, you may have a faulty fan. You can try to spin the fan manually and see if it rotates smoothly. If it feels stiff or makes noise, you may need to lubricate or replace the fan.

If the fan is spinning, but not enough to cool down the part, you may have a problem with the fan speed, the fan duct, or the print settings. To test the fan speed, you can use a tachometer to measure the revolutions per minute (RPM) of the fan. The RPM should be around 3000 to 5000, depending on your printer model. If the RPM is too low, you may need to increase the fan speed in your slicer settings or replace the fan with a more powerful one.

If the fan speed is fine, you can check the fan duct for any blockages, cracks, or misalignments. The fan duct is the part that directs the airflow from the fan to the nozzle and the part. You can use a flashlight to inspect the inside of the duct and see if there is any dust, debris, or filament stuck inside. You can also check if the duct is cracked or broken and if it is aligned properly with the nozzle and the part. If there is any problem with the duct, you may need to clean, repair, or replace it.

Finally, you can check your print settings for any factors that may affect the cooling performance. Some of these factors are:

• Layer height: A lower layer height means more layers and more time for cooling.
• Print speed: A slower print speed means more time for cooling.
• Fan speed: A higher fan speed means more airflow and more cooling.
• Minimum layer time: A longer minimum layer time means more time for cooling.
• Cooling threshold: A lower cooling threshold means more layers with full cooling.
• Bridging settings: Bridging settings control how much cooling is applied when printing overhangs.

You can experiment with different combinations of these settings and see which one gives you the best results. You can also use some online tools or guides to help you optimize your settings for different materials and models.