Mô hình quạt nâng cấp Prusa MK4s cho đầu in MK3s

MODEL IN PROGRESS!!!

*Disclaimer: Use it at your own risk! The printer uses stock Einsy board and there is difficult to find compatible fans 5020 size.

Current state:24V 4 Watt 2 wire fan running Ok

28/3/2025 - Dual opto-isulated circuit designed to use reconverted 2 wire aftermarket fans using the existing Einsy fan output including tachometer signal. CAUTION!!! This conversion needs to solder an aditional wire to a normal 2 wire DC fan in order to aquire an AC signal to sense RPM. This may damage the fan so use it at your own risk:

26/3/2025 - Opto-isulated circuit implemented to drive aftermarket fans using the existing Einsy fan output. Can drive almost any 2 wire DC fan regardless of voltage or current. Electric noise is now completly gone. Now testing 24V 5020 blower:

Benchy 0.2, 2 shells, 15% cubic infill, standard PLA, 220ºC - 30 minutes

05/9/2024 - V3 fan shroud slightly improves airflow direcction. Succesfull print test, helix 100mm height per turn:

02/9/2024 - Electrical noise is almost gone due a shorter and cleaner wire routing. The original path goes around the motor creating kind of a “coil loop” so enhances inducction current causing electric noise. 2 wire fan is now functional.

29/8/2024 - Electric noise is causing bad sensor readings. The Einsy board shares 5V power supply between sensors and fans. Bed sensor readings below the real temperature when the fan is running even slow, 30%. Waiting for a new fan to test.

Temperature reading decreases so the PWM increases duty cycle to compensate it. In this example the thermistor reads 95ºC but the bed surface is around 125ºC according to an infrared thermometer. At this high temperatures the PWM reaches its maximum duty cycle but temperature still decreasing triggering “Heater ERROR”.

At 55ºC bed temperature the PID is able to reach the setpoint temperature but the real value is significantly higher, around 65ºC so the PLA softens too much on the first layer.

28/8/2024 - ASA material is not able to handle the heat. Looking for new materials.

27/8/2024 - Compatible fan fitted. Printing tests in progress.

22/8/2024 - A bit Smaller/lighter case and cover version. Original mounting holes removed.

17/8/2024 - Printed parts fitting OK.

Extruder cover must be R6 version.

2.5mm ball end hex key should be used in order to reach some bolts.

Notice that one of the threaded inserts MUST be inserted 2 mm only!

The current fan drains about 200 mA at full speed. Normal printing is 70% still testing.

Noise at these speed is almost the same as the stock one.

Hardware needed:

• 2 x Bolt M3x10 (1 reused)
• Bolt M3x8
• Bolt M3x6
• 2 x Bolt M3x[4 to 8 mm can be used]
• 2 x Square nut M3 (1 reused)
• 2 x Threaded insert M3x3.5 (the shortest one) Optional version

Anyone who wants to test and comment will be apreciated.