Simple Belted Dual Z Hellper for ELEGOO Neptune 2 / Neptune 3

This is a Simple Belted Dual Z Helper based on the Poor Man's Dual Z for Ender 3 by @tmackay. The theory is similar to drafting tables with a long history and is simple and working well.

The theory of the original

There is a tensioning belt routed left-bottom to right-top on and between the both Z axes. The stock leadshaft of the printer is also used.

When the left Z carriage moves up by the stock leadshaft, the left V-Slot wheel transforms the up force to the belt tension. Then the right V-Slot wheel transforms back the belt tension to an up force. This force assists the right Z carriage moves up as same as the left. Totally, the X gantry moves up perfectly parallel.

Notes

In this mechanism, it is important that the Z belt parallel to the Z axes. If the Z belt is not parallel to the Z axes, the length of the belt path changes related to the Z position.  In that situation, the X gantry does not move up parallel.

The original Z belt path is not parallel to the Z axes about 2mm at the endpoints. I made this mod to fix it.

This mod: Fixed version of belt holder

This is the brand new design of belt holders based on the original theory.

The both endpoints of the belt path are 1.9mm inner from the surface of V-Slot and the belt path is almost parallel to the Z axes. The accuracy of the Z travel is more improved.

And the belt clip is using a little piece of filament and the body height is more than 10mm compact from the original.

Compatible printers

I confirmed this working on ELEGOO Neptune 2, and this can be used also on Neptune 3, Ender 3 and clones.

BOM

See also

Rigid stable Z lead shaft upper holder for ELEGOO Neptune 2 / Neptune 3 for the accuracy of the Z movement and printing is improved.