Neptune 3 Pro/Plus/Max Voron Afterburner adapter (BTT Eddy support)

UPDATE

• 2025.08.29: Added the PCB mount
   
• 2025.09.09: Added the cable guide

INFO

My Afterburner adapter plate allows the use of the Afterburner toolhead with the Neptune 3 series (not base). It also replaces the motor plate part of the original Afterburner. The other printed parts can be sourced from the official Voron Afterburner GitHub.

Why the Afterburner?

The cool thing about the Afterburner is that you can reuse all of the extruder parts of the Neptune (including the stepper motor). Taking apart your extruder is non-reversible as you will need to permanently “destroy” a plastic piece. You can avoid this buy just buying an Afterburner gear set for a couple of bucks. This is also an easy way to use a volcano hotend with your Neptune. 

The new parts you need:

• A compatible heatsink and heatbreak as the heater block and nozzle can still be used. The stock heater block could for example be used together with a V6 heatsink and heatbreak. Any hotend compatible with the Afterburner toolhead can be used but check first that the printer can actually handle your hotend of choice (wattage requirement and voltage).
   
• A 4010 fan to cool the heatsink
   
• A 4020 fan is the normal cooling fan used in the Afterburner. But there are plenty of other user mods to use other/more cooling fans with the Afterburner. If you mainly print ABS the stock cooling is should be enough but for PLA more cooling is recommended.

Compatability:

Probes:

• Default Probe (adjustable height)
   
• BTT Eddy (adjustable height) 
  See here for a fitting Klipper config.

Hotend:

• Compatible with any hotend the Afterburner is compatible with. The probe mounts support up to v6 volcano hotends in length.

REQUIRED HARDWARE

Mounting to the X-carriage

• M3 x 8mm screw (x2) (can be salvaged from the original toolhead, the ones holding the fan cover in place)
   
• M3 x 15mm screw (x1) (use the one in the picture, which is between the lower POM wheels of the X-carriage):

• M3 Nut (x1) used to tighten the middle screw, it goes between the lower two wheels of the X-carriage where the screw was before (see image above)

For the Afterburner toolhead

• The two screws to mount the extruder assembly to the Afterburner carriage are not needed. Instead one M3 x 8mm screw is required to mount the extruder body to the adapter plate. It is screwed in from behind into the marked hole:

                 Note: This is an older design of the Afterburner adapter that looks a bit different but it still works the                    same way

• Otherwise the rest of the hardware needed for the Afterburner stayed the same

Probe Mouting

• M3 × 8mm screw (x2) to attach the probe bracket 
   
• M3 washer (x2) (Optional but recommended) to put between the probe bracket and the screw head
   
• M3 x 5mm (W) x 4mm (L) threaded inserts (x2)
   
• For default probe: 
  • M3 x 5mm (W) x 4mm (L) threaded insert (x1)
  • Original screw for mounting the probe to the printhead
     
• For BTT Eddy:
  • M3 x 5mm (W) x 4mm (L) threaded inserts (x2)
  • The two Eddy mounting screws that come with it

PCB Mounting

• M3 × 6mm screw (x2) to attach the pcb mount
   
• M3 x 5mm (W) x 4mm (L) threaded inserts (x3) to attach the pcb to the pcb mount
   
• M3 × 6mm screw (x3) to attach the pcb to the pcb mount

Cable Guide

• M3 × 25mm screw (x2) to attach the cable guide to the stepper motor
   
• M3 nut (x2) to attach the cable guide to the stepper motor

ASSEMBLY

1. Add the threaded inserts to the side where the probe bracket will be mounted:
    
2. Add the threaded inserts for mounting the PCB mounting bracket later:
   
   Note: The printhead is assembled in this image to show what it will look like.
    
3. Add the threaded inserts to the PCB mounting bracket:
   
   Note: The cutout at the bottom of the probe mount can be used to run the stepper cable through it because the connector is located on the other side of the PCB.
    
4. Add all of the other threaded inserts required for the Afterburner.
    
5. Attach the Afterburner extruder assembly to the plate as you won't be able to access all of the screws once it has been mounted to the X-carriage. One of the threaded inserts isn't required as it would normally be used to mount the motor plate to the carriage (because these two parts have been fused together to create the adapter plate). I also removed the hole for that!
    
6. Mount the adapter plate to the X-carriage:
   - Blue Arrows: M3 x 8mm screw (x2)
   - Green Arrow: M3 x 15mm screw (x1) + M3 Nut (x1)
   
    
7. Assemble your Afterburner toolhead, mount the pcb to the printhead and attach the probe mount to the appropriate height. 
   Note: Some cables such as the cable of the probe need to be lengthened when using my PCB mount. It is also recommended to have the printhead cable run around the left Z-axis extrusion, not inbetween then how it's done with the stock prinhead. Otherwise the maximum print height will be significantly reduced. Depending on what hotend is used the maximum print height will be reduced by up to ~10mm (for volcano hotends), so not very much.
    
8. Screw the nuts onto the screws (the nuts are used to shorten the thread length):
   
   Remove the two top screws of the stepper motor (shown in image) and attach the cable guide to the stepper motor using the two new screws with the cables already guided through it.
   

FIRMWARE

Default Probe:

• X-Offset: +42.75mm
   
• Y-Offset: +8.5mm

BTT Eddy:

• X-Offset: +45.15mm
   
• Y-Offset: +5.45mm

PRINTING

• No Supports for all of the models.
   
• Print flat on the build plate.
   
• Print in the same material as you print your Afterburner parts in, so preferably ABS, certain fibre-reinforced materials or high-temp materials.

A mount remixed for the Neptune 3 series and an added hole for compatibility with my original pcb mount.