If you are searching for a better way to feed the filament into your Neptune printer, you've come to the right place.

This design replaces the stock spool holder of multiple models of the Elegoo Neptune series printers. The filament sensor is now centered, pivoting on a 10mm ball joint, making for a less-rattly print. You can use a short piece of PTFE tube, as seen in the example, or drill through one of the end stops, making your way to the dry box. 

In addition, this filament guide is fully compatible with my belt tensioner.


To make this model you'll have to acquire ~25cm (~10inch) of 4mm PTFE tubing (Cut as necessary. Make sure the filament sensor stays vertical). 2x M2x10mm screws, securing the placeholder, are optional. As is the snap-fit placeholder itself. Stock screws that hold the spool holder, and two Phillips-head screws that screw into the filament sensor will be reused. Finally, the “Bracket_barrel” is glued to the “Bracket_plate” and the “Bracket_placeholder” with a couple of drops of CA glue.


I should note that there will be some minor post-processing:
1. Holes for the PTFE tube will require drilling to the size (4mm).
2. Holes for the filament sensor are ever-so-slightly too close. They will enlarge as you put the screws in, so it should fit alright (I am open to updating the model, so more precise measurements are appreciated).

UPD: testing has shown significant drag, caused by conically-drilled bowden-stops pulling in the bowden tube, forming a chuck of sorts. Thus, I recommend drilling out the holes with a 4.5mm drill bit (for a 4mm OD PTFE tube) and securing the tube in the “beam” part by wedging it with a filament.

UPD: new barrel and beam version added (5mm hole, as opposed to old 4mm). No postprocessing should be required).

UPD: throughout my testing, there were severe underextrusion, and delamination issues. Besides the tight PTFE tube, and poor hole alignment, the main culprit is the excessive tension between the filament sensor and the printhead, causing the latter to lift. To anyone experiencing bad print quality, I suggest using a PTFE tube between the printhead and the sensor, eliminating the tension.

Anyway, I hope this model fits your needs. Do leave a make and/or a comment.

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