1.Fan type selection

Axial flow fans (common fans)

Have a large air volume but low air pressure, suitable for overall heat dissipation (such as motherboard, power supply, and heat sink at the hot end).

Example: 4010, 4020 fans (diameter 40mm, thickness 10/20mm).

Centrifugal fans (turbine fans)

Have high air pressure and concentrated airflow, suitable for targeted cooling of printed parts (such as throat pipe cooling or local cooling of models).

Example: 5015 centrifugal fan (diameter 50mm, thickness 15mm, commonly used for Part Cooling).

2. Heat dissipation location and function

Hot-end cooling fan

Function: Cool the heat sink and prevent heat creep.

Requirements: Continuous operation, low noise (such as 4020 silent fan).

Model cooling fan (Part Cooling)

Function: Rapidly solidify the extruded material and improve overhang structures.

Requirements: Adjustable fan speed (controlled by PWM), high air pressure (centrifugal fan is recommended).

Electronic component cooling

The mainboard and stepper motor driver module (such as TMC2209) may require additional cooling fans.

3. Fan control strategy

Hot-end fan: Always on or linked to the hot-end temperature (starts when it exceeds 50°C).

Model cooling fan:

Off for the initial layer (to avoid warping), and gradually increase the wind speed for subsequent layers (0 to 100% PWM).

For complex overhanging structures, set the wind speed to 100%.

Silent optimization: Use PWM speed control or 24V fans (quieter than 12V fans).

4. Key points of the air duct design

Uniformity: The air outlet needs to cover the entire nozzle area (to avoid deformation caused by single-sided cooling).

Lightweight: The air duct is recommended to be made of PLA+ or PETG (with better temperature resistance).

Classic solutions:

Radial air duct (such as Hero Me Gen7): Multi-directional air outlet, uniform cooling.

Ring-shaped air duct (such as Cooling Ring): 360° surrounding the nozzle, suitable for high-speed printing.

5. Common Issues and Solutions

Insufficient heat dissipation:

Upgrade the fan (e.g., replace the 4010 axial fan with a 5015 centrifugal fan).

Optimize the air duct structure (reduce air flow loss).

Excessive noise:

Replace the fan with a hydraulic bearing one.

Fix the fan with silicone shock-absorbing pads.

Thermal creep blockage:

Check if the heat sink fan at the hot end is faulty or replace it with a model of higher air pressure.

6. Recommended configuration example

Low-cost solution:

Heat sink at hot end: 4020 axial fan (24V).

Model cooling: Single 5015 centrifugal fan (PWM control).

High-performance solution:

Dual 5015 centrifugal fans (symmetrical air duct).

Independent control of the heat sink and model cooling fans.

7. Notes

Avoid having the fan blow directly on the heated bed, as it may cause warping of materials like ABS or nylon. Regularly clean the fan of dust to prevent performance degradation. Ensure that the filament is securely fastened to avoid getting tangled in the fan. By choosing the right type of fan, optimizing the air duct and control strategy, the print quality and reliability can be significantly improved. It is recommended to refer to the mature modification schemes in the community based on the specific printer model (such as Ender 3, Prusa i3, etc.).