How to Install the Prusa i3 Mosquito® Upgrade Kit (MK3S+)

Overview

Materials 

Prusa i3 (MK3S+) - Mosquito® 

1. The Mosquito® Hotend
2. Mosquito® Silicone Boot
   
3. BridgeMaster® 0.4 mm Nozzle
   
4. Boron Nitride Paste (5cc) w/ Applicator Swabs
   
5. Hotend Wrench Set (2.0 mm, 1.5 mm, and 1.3 mm hex keys)
   
6. PTFE Tubing (27.5 mm)
   
7. Printed Extruder Components
   
8. Assembly/Disassembly Aid Placemat
   

Tools (not provided)

1. 2.5 mm hex key
   
2. Adjustable wrench and/or pliers
   

Removal and Disassembly of the Existing Hotend 

Before removing the current hotend, you may find it easier to remove any filament that is currently loaded. While this is not required, it will make the process easier. Follow all standard safety steps while removing filament from the hotend.

1. Ensure the hotend has been allowed to cool down to ambient temperatures.
2. Turn off the power to the printer and remove the power cord.
   
    
3. Using a 2.5 mm hex key, remove the two M3x20 screws attaching the part cooling fan to the extruder. 
   
   
   
   
4. Using a 2.5 mm hex key, remove the three M3x14 screws and the one M3x20 screw attaching the hotend cooling fan to the extruder body. 
   
   
   
   
   
   
5. Using a 2.5 mm hex key, remove the two M3x40 screws directly under the extruder stepper motor securing the extruder cover to the extruder body. 
   
   Remove the extruder cover.
   
   
   
6. Using a 2.5 mm hex key, remove the 
   

   Part Cooling Fan Support Arm from the extruder cover. At this point, the extruder cover can be stored as it will not be used again. 
   

   

   
   
    
7. Using a 1.5 and 2.0 mm hex key, loosen the two screws on the underside of the hot block securing the thermistor/heater cartridges to the stock hot block. You may need to hold the hot block with a wrench or pliers to loosen the screws successfully.
   
   
   
   
   
8. Remove the heater and sensor cartridge from the hot block.
   
   
   
9. Using a 2.5 mm hex key, remove the M3x10 screw located on the top of the extruder body attaching the filament sensor cover to the extruder body. The screw and cover can now be removed. 
   
   
   
   
10. Using a 1.5 mm hex key, remove the M2x8 screw located on the top of the IR filament sensor. Once the screw is removed, gentle remove the sensor from the extruder body and push it out of the way. 
    
    
    
    
11. Using a 2.5 mm hex key, remove the top two M3x40 screws on the back side of the x-carriage. These screws can be left in the x-carriage for later assembly, as shown in the second image.  
    
    
    

    
     
    
12. Gently pull th
    
    e extruder stepper motor away from the extruder body.
    
    
    
    
13. Remove the stock hotend from the extruder body. Using a 2.5 mm hex key, remove the m3x10 screw clamping the SuperPINDA Sensor to the Extruder Body. Once the screw is removed, remove the SuperPINDA Sensor.
    
    
    
    
14. Using a 2.5 mm hex key, remove the M3x18 screw attaching the filament sensor lever to the extruder body. 
    
    
    
    
15. Using a 2.5 mm hex key, remove the M3x40 extruder tensioning screw and spring.
    

    
    
    
16. Using a 2.5 mm hex key, remove the two M3x10 screws attaching the extruder body to the x-carriage.
    

    
    
    
17. Remove the filament guide adapter and the steel ball from the extruder body. Care must be taken to avoid losing the steel ball. 
    
    
18. Using pliers, grab the 20x6x2 magnet and remove it from the extruder body. The extruder body can now be removed as it will not be reused. 
    

    
    
    
19. Using a 2.5 mm hex key, remove the two M3x10 screws attaching the extruder motor plate to the extruder stepper motor. The extruder motor plate can now be removed as it will not be reused. 

Installation of The Mosquito® Hotend

1. The following printed extruder parts included in your kit will replace the stock printed extruder parts.
   
   
   
   
2. Insert the 20x6x2 magnet into the Extruder Body.
   
   
   
   
3. Using a 2.5 mm hex key, attach the filament sensor lever to the extruder body with an M3x18 screw. 
   

   

   
   

   
   
4. Insert the filament guide adapter with steel ball into the extruder body. 
   

   

   
   
5. Using a 2.5 mm hex key, attach the extruder body to the x-carriage using two M3x10 screws.
   

   

   
   
6. Remove the Mosquito® Silicone Boot from the hotend. 
   

   

   
   
7. Using a 2.0 mm hex key, remove the retaining screw to the right of the Slice Engineering® logo on the hotend. (Left retaining screw is missing from the hotend in the photo but will be present in the final product. The left retaining screw is not removed.)
   
   

   
   
8. Apply a small amount of Boron Nitride Paste to an applicator swab. 
   

   

   
   
9. Thoroughly coat the heater and sensor cartridge with Boron Nitride Paste.
   

   

   
   
10. Insert the heater and sensor into the hot block. Excess Boron Nitride Paste can be cleaned with a damp cloth or swab. 
    
    
11. Using a 2.0 mm hex key, install the hot block retaining screw to secure the heater and sensor in the hot block. 
    

    

    
    
12. Install the Mosquito® 
    

    Silicone Boot. 
    

    
    
    
13. Press The Mosquito® Hotend into the Extruder Body. The front of the hotend should be facing the SuperPINDA mount.
    

    

    
    
    
14. Attach the extruder motor plate to the extruder with two M3x10 screws.
    

    
    
    
15. Attach the extruder motor/plate to the extruder body. 
    

    
    
    
16. Place the extruder idler lever in the extruder body. Using a 2.5mm hex key, tighten the two M3x40 screws at the top of the x-carriage. 
    

    
    
    
17. Using a 2.5 mm hex key, install the M3x40 extruder tensioning screw with spring. 
    

    

    
    
18. Using a 1.5 mm hex key, attach the IR-sensor to the extruder body with an M2x8 screw. 
    

    

    
    
19. Using a 2.5 mm hex key, attach the filament sensor cover to the extruder body with an M3x10 screw. 
    

    

    
    
20. Using a 2.5 mm hex key, attach the Part Cooling Fan Arm and extruder cover to the extruder body assembly. The part cooling fan arm will be attached with one M3x10 screw. The extruder cover will be attached with two M3x40 screws. This is also a great point to install the fan shroud onto the extruder cover.
    

    

    
    
21. Using a 2.5 mm hex key, attach the hotend cooling fan to the extruder. Ensure the M3x20 screw is installed in the bottom right position as shown below. Three M3x14 screws will be used in the remaining three screw holes. 
    

    

    
    
22. Using a 2.5 mm hex key, attach the part cooling fan to the extruder with two M3x20 screws.
    

    

    
    
23. Push the SuperPINDA sensor into the mount on the side of the extruder body. The bottom of the sensor should be slightly higher than the bottom of the nozzle. Tighten the sensor in place using an M3x10 screw and a 2.5 mm hex key.
    

    

    
    
24. We made it to the final step. Great job! Now all that's left is to perform a PID tune, calibrate your Z axis (I suggest running "Calibrate Z" and the "First layer cal." under "Calibration" on the main menu), and start printing. 
    
    

The table listed below is a recommended starting point for certain slicer settings when using this upgrade. It is best practice to calibrate your slicer settings when using new components/filaments. This is most commonly done by printing a temperature tower and retraction tests.

All listed specifications are based on the use of a 0.4 mm nozzle. The suggested settings below can, and in most cases should, be adjusted to optimize your particular printer's performance.