Dual Z Sync Belt Tensioner

Hello Makers

Dual lead screw for Z axis generally offer more precise motion in Z direction. However, at power off, it is quite common the Z motors go out of sync. This is especially the case for the CR-10S Pro. To counteract this, I fitted my printer with the "CR-10S Pro Dual Z Sync" from TORX1.

As I wanted better control over the belt tension (and had my issues sourcing a 720mm closed GT2 timing belt in Thailand...), I designed a Z axis sync belt tensioner inspired by Cornely_Cool's X axis mod (https://www.thingiverse.com/thing:2854971). The design has a clean belt path, allows precise belt tension and gives more options with respect to the length of the closed belt.

What you'll need for the entire mod:
1) 2 x Flange bearings KFL08
2) 1 x 6mm wide GT2 timing belt 840 to 880mm
3) 2 x GT2 Gear pulley with 20 teeth and 8 mm bore
4) 3 x GT2 Idler
5) 3 x M5x25 screws
6) 4 x M3x10 screws, nuts and t-nut adapters (https://www.thingiverse.com/thing:3050607)

Print out the Knob, Screw and Tensioner Body. I included three sizes, depending on the length of your GT2 Belt. To install the tensioner you can follow the posted pics:
1) Put the Knob and the Screw part together
2) Insert both parts in the Tensioner Body
3) Install an idler in the Screw part including closed belt
4) Install the remaining two idlers in the Tensioner Body (the closed belt should run between the two idlers)
5) Loosely install the M3 screws and t-nuts.
6) Mount the Tensioner to the frame of your printer and make sure the belt is nicely aligned.

For instructions how to install the TORX1's mod, please check https://www.thingiverse.com/thing:4339307.

I hope you enjoy my design...Check out my blog at https://allpro3d.com !

Cheers and keep making

PS:
This tensioner body and the screw part print without supports. The Knob part needs supports on the inside to the thread. Check the pictures for print orientation.

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