A1 / A1Mini Print 360° Cooling Fan Mod- A1 AeroFan

A Few Words of Introduction

But if you want to improve efficiency and boost cooling performance on your A1 / A1 Mini, this  A1 AeroFan mod is for you.

 A1 AeroFan - Boost cooling performance – quick and easy mod for A1 / A1 Mini!

This project is a fast modification of the stock print cooling fan. It combines a compact case, the powerful A1 fan, and a 360° fanduct inspired by Prusa MK4S. It delivers improved airflow, especially useful for bridges and sloped walls.

And a few more words about the project…

This is my third adaptation of the Prusa 360° fanduct geometry from the MK4S. This is not just a scaled-down MK4S fanduct glued onto the A1 fan housing…

 The project was created almost entirely from scratch. At the beginning, I defined several fixed requirements:

• the impeller size (based on the original A1 impeller),

• the outer dimensions of the new fan not exceeding the original (the screw mounting points extend slightly beyond the outline, but do not affect printer operation),

• the distance between the fan, the nozzle axis, and its bottom plane: the lower edge of the fan outlet is positioned 2 mm above the nozzle tip plane, and the nozzle axis aligns with the outlet geometry axis (the hotend axis does not align with the fan outlet axis, just like in the original design, but it has no impact on cooling performance).

Taking these constraints into account, I calculated and designed a completely new volute for the fan. I determined the correct angles in three planes of the outlet channel window, oriented toward the nozzle axis and bottom plane. I then designed the outlet dimensions and shape accordingly, using the Prusa MK4S geometry as a reference.

 Designing this was an adventure in physics, geometry, calculations, and an attempt to create something seemingly impossible — a compact fan with a built-in Prusa MK4S fanduct geometry…

I hope you enjoy working with this project!

BOM

To build it you will need:

• the original A1/A1mini fan,

• two 683zz ABEC-7 bearings (3x7x3mm),

• some ABS/ASA filament or similar.

• Optionally, ASA/ABS glue may be useful.

The new cooling system will require the following parts taken from the original fan:

• the rotor with the pressure spring,

• the motor stator with the original connector,
   

• four mounting screws and the rotor shaft lock,
   

• three screws securing the original fan to the A1 extruder.
   

Additionally, you will need two new 683zz bearings — I recommend FUSHI 683zz ABEC-7. 

                                                                             !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Many thanks to @volkov – his feedback helped improve the design and the instructions needed for a stress‑free assembly.

                                                                             !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

DISASSEMBLY OF A1 FAN

• Take a photo of the assembled fan connector, then carefully slide the pins out of the plastic housing.
  YouTube link: https://www.youtube.com/watch?v=q8tU_NEZK9g
  it shows how to disassemble the fan connector.

• Unscrew the four mounting screws of the fan and keep them – they will be needed later.

• Peel off the sticker and stick it onto a strong foil – it will be needed later.

• Open the fan housing. YouTube link: https://www.youtube.com/watch?reload=9&v=c9h4XsP8zUA
   From 2:08 onwards, it shows how to disassemble the fan.

• Carefully slide the cable with pins out of the housing.

• Remove the rotor shaft lock and keep it – it will be needed.

• Pull out the rotor and keep it – it will be needed.

• Remove the bearings – one upwards, the other downwards.

• Extract the motor stator. 
  The stator is factory‑glued to the housing sleeve 

• – gently heat it with hot air and carefully slide it out of the plastic sleeve, taking care not to damage the wires. To remove the stator, grip its iron core (do not pry the PCB to avoid damage) and carefully but firmly pull it out without rotating around the axis.
   

Now you should have the fan fully disassembled.

PRINT MOD PARTS

The printed parts must be highly accurate to allow proper installation of new bearings and the motor stator.
I assume your printer is calibrated correctly for the filament you plan to use.
I strongly recommend verifying your printer’s calibration with a simple test print.
The method is very simple. Print the two Voron parts linked below and check if they fit together:

• Guidler A

https://github.com/VoronDesign/Voron-Stealthburner/blob/main/STLs/Clockwork2/Direct_Drive/%5Ba%5D_guidler_a.stl

• Guidler B

https://github.com/VoronDesign/Voron-Stealthburner/blob/main/STLs/Clockwork2/Direct_Drive/%5Ba%5D_guidler_b.stl

Check whether they are too tight or too loose:

• If the assembled parts are too loose, your printer likely has too low flow rate.

• If the assembled parts are too tight, your printer likely has too high flow rate.

If the parts fit together correctly—move on to the next step. If they do not fit, recalibrate your printer so that the newly printed Voron parts match properly.

 

Print the assembly tools using PLA for best results.

Print the parts using ABS/ASA for best results.

Printing settings:

• Nozzle: 0.4 mm

• Layer height: 0.2 mm

• Infill: min25%

• Perimeters: 3

• First layer height: 0.2 mm
  
  The model is designed for a standard Voron print with a 0.2 mm layer height. If you really want to print with a smaller layer height, choose a value that is a multiple of 0.2 mm, i.e. 0.1 mm (not tested). This way you can avoid potential, unforeseen fitting issues that may occur if the print differs from the standard 0.2 mm setting.
  
  !!! The front part of the housing has a built-in break-out support—remove it gently. !!!
  

  
  

ASSEMBLY

Before assembly, clean the edges of the printed parts where the brim was attached. Pay special attention to the edges that will contact each other after assembly.

The bearings must be installed using the Bearing_press_tool. This method prevents damage during installation — as a result, the fan runs more quietly and the bearings have a longer lifespan.

• Insert the bearings into the lower half of the motor housing: 
  – one from the top, 
   

• 
  – one from the bottom.
   

• Slide the stator wire through the hole in the lower housing.

  

  
  Then push the stator onto the housing sleeve until it stops – the electronic components on the PCB should fit into the proper recesses in the lower housing, and the wire should align with the designated slots (as shown in the photo).
   

  

  
  

  

  
  For a more secure fit, you may apply a drop of glue before sliding the stator, just like in the original fan.

• Insert the rotor with the spring mounted on the shaft from the top into the upper bearing hole. The shaft should pass through both bearings. Turn the assembled lower housing and place the shaft lock onto the rotor shaft.
  

  

  
  

  

  
  

  

• Press the lock with a retaining_ring_press_tool until it clicks into place.
  
  

  

  
  

• Fasten the upper and lower housing parts together using two original screws, then attach the outlet duct with the remaining two screws.
  
  !!!Check that the rotor rotates without rubbing against the housing.!!!
  
  

  Note: When fastening the upper and lower parts with the two screws, make sure that the screw heads are flush with the surface of the upper part. If you tighten these screws too much (the heads sink deeper), it will cause the rotor to hit the shroud — a known issue with stock fans, shown in the video: https://www.youtube.com/watch?v=dNCGkC3BHe4

  
  
  When assembling the enclosure, pay attention to the special system of slots and tabs that ensures proper alignment of all three parts.
  
  

  
  

  
  
  

  

  
  

  

  
  

  

When fastening, I recommend using acetone‑based glue – apply it to the surfaces that will contact after assembly. This seals the joints, and the acetone slightly softens the surfaces, allowing the parts to fit together more tightly.
 

• Attach the original sticker to the bottom.

• Insert the wire pins into the correct slots in the plastic connector housing, using the photo you took as a reference.

Now install the fan in the extruder using the three original screws, following the Bambulab instructions.

1. Start by tightening the two side screws.
2. Tighten the third screw at the end once the previous two have been correctly installed.

For the design and visualization, I used the model:

https://grabcad.com/library/bambulab-a1-hotend-1

Want to check out my previous cooling mods:

https://www.printables.com/model/1092122-mk3smk35-360-degree-print-cooling-modeled-after-mk

https://www.printables.com/model/1111556-artillery-360-degree-print-cooling

NOTES:

****************************************************************************************************************************************************************************************************

Updated 01.12.2025

Updated description.

The most significant change is the addition of the Bearing_press_tool. If you previously installed bearings with your fingers or another tool, such as a screwdriver or pen, you may have damaged them during installation, causing noise when the fan is running and significantly reducing the service life of the bearings.

Installing bearings with the Bearing_press_tool does not damage the bearings during installation, allowing the fan to run more quietly and increasing the service life of the bearings.

New important tips for correct installation have been added.

An improved version of the A1 AeroFan has been added.

The new fan housing parts are not interchangeable with the previous version.

****************************************************************************************************************************************************************************************************

Updated 01.12.2025

Updated description.

Updated part: a1_front_housing_v1.stl 

It fits better for mounting on the extruder. 

The remaining bottom and top parts have been correctly rotated for printing on a 3D printer.