Dual Z Mount for Anycubic Mega Zero by 1CM69

Last crawled date: 3 years, 1 month ago

I got inspiration from: https://www.thingiverse.com/thing:3796938
and thought that this was a extremely clean and simple answer to adding a second Z stepper & leadscrew to my Anycubic Mega Zero 2.
Having tried many other designs to attempt this upgrade/mod, each failing for some reason, this too did not work out for me.
I know, it's specifically for the Ender 3 & I am using a Mega Zero, so no surprise that it does not work but I have no idea why before now I didn't see the problem when using these Ender 3 designed mounts with my Mega Zero, even if I'd mirrored the model in CURA (as the Mega Zero's X gantry is opposite to the Ender's).
Most of these type of printer all look the same or very similar and I took that for granted, fool me, however it turns out that the hole centres between the top & bottom wheels running on the Z axis of the Ender is 72mm, on the Mega Zero this is 70mm.
Obvious to me now that this is why all the previous Ender 3 mounts caused a certain amount of binding when attempting to implement the dual z axis mod on my Mega Zero.
With all that said I decided that I needed to design a mount to properly mod my Mega Zero for a dual Z axis setup.
My design contains a number of parts:
Leadscrew_Mount_[PART-A] - this is the main carrier and is attached to the front side of the left hand X gantry carriage via the wheel screws.
This means that it is not necessary to move the PSU from it's OE fixings on the Mega Zero 2.
Leadscrew_Mount_[PART-B][16mm] & Leadscrew_Mount_[PART-B][18mm] - basically the same part but while designing this I found that there are a couple of different rectangular leadscrew nuts, either 16mm or 18mm centres between the fixing screw holes.
Print whichever one suits the leadscrew nut you have.
Stepper_Mount - this is the mount that attaches the second Z stepper to the outside of the printers frame.
Z_Align_Block - these are optional but do aid with alignment (sync) of the Z axis, you'll need to print 2 of these.
My print settings are as follows:
All parts except the Z Align Blocks - LH 0.12mm 100% Infill in PETG
Z Align Blocks - LH 0.2mm 100% Infill in PLA
NO Supports required.
I chose to use 100% infill for added strength & 0.12mm LH for the majority of the parts for fit & finish.
Hardware used as follows:
PART-A to X carriage - 2x M5x35mm machine screws hex button head + thin washers & use existing M5 nyloc nuts.
PART-B to PART-A - 2x M3x20mm machine screws hex button head & 2x M3 nuts. Plus optional solvent to weld parts together.
Leadscrew nut to PART-B - 2 x M3x15mm machine screws hex button head & 2x M3 nuts if required (some leadscrew nuts are threaded).
Stepper Mount to frame - 2x M5x16mm machine screw hex button head & 2x M5 T-Nuts.
Stepper Motor to Stepper Mount - 4x M3x8mm machine screws & thin washers.
Z Align Blocks to frame - 2x M3x20mm machine screws & thin washers & 2x M3 T-Nuts each.
The Stepper Mount allows for some alignment to get the leadscrew running as true as possible.
I decided against using or designing leadscrew stabilizers as there is talk that the ends of the leadscrews need to be free & not transfer any wobble to the printers frame.
For Z axis sync with a dual axis setup I followed this YouTube video:
https://youtu.be/U_RiwMSG9rE
but I used fixed blocks (Z Align Blocks) on the inside of the Z axis frame on my printer & placed a starting GCODE in CURA as well as adding a Custom Menu option in Marlin.
In CURA:
; ALIGN DUAL Z
M117 Homing Z ...
G1 Z0 ;move Z to min endstops
M117 Homing X/Y ...
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0
G1 Z200 ;MAX HEIGHT
G28 Z0 ;move Z to min endstops
M117 Z Axis Synced
; END OF ALIGN DUAL Z
In Marlin - Configuration_adv.h:
'#define CUSTOM_USER_MENUS'
'#define USER_DESC_1 "Align Z Axis"'
'#define USER_GCODE_1 "G1 Z0\nG28\nG1 Z200\nG28 Z0\nM117 Z Axis Synced"'
'CHANGE Z200 TO YOUR OWN REQUIREMENTS AFTER FOLLOWING VIDEO ABOVE'
Hopefully this all makes sense & I have included everything required.
Thanks for looking.
p.s. wise to perform a new bed level after fitting this mod & running the 'Align Z Axis' option.