Bed leveling on DuetWifi+Duex5 using 4 independent Z motors

otaku521

I have been using 3 independent Z motors on my CoreXY (HyperCue Evo) machine... Currently, the bed is configured as:
Left Front - Stepper Motor with Lead Screw (Z0)
Left Rear - Linear Bar with Bearings/Bushings
Right Front - Stepper Motor with Lead Screw (Z1)
Right Rear - Linear Bar with Bearings/Bushings
Middle Rear - Stepper Motor with Lead Screw (Z2)

and I am thinking of experimenting of adding a 4th independent Z motor... so I can get rid of the Linear Bar with Bearings and just mounting the 4 Stepper Motors with Lead Screw at each corner alone - would this be correct? or do I still need linear bars with bearings/bushings? Please advice, Thanks!

S1lencer

Hi the Linear rails/bars are provide the Stability an accuracy and the Screws provide the movement/motion of the system. No screw is that accurate that you dont have an possibly x/y movement of the table.

otaku521

Thanks! What would you recommend?

Adding 2 linear bars+bearing/bushings in the middle?
Left Front - Stepper Motor with Lead Screw (Z0)
Left Middle - Linear Bar with Bearings/Bushings
Left Rear - Stepper Motor with Lead Screw (Z1)
Right Front - Stepper Motor with Lead Screw (Z2)
Right Middle - Linear Bar with Bearings/Bushings
Right Rear - Stepper Motor with Lead Screw (Z3)

Or Go extreme with 4 Linear Bars with Bearling Busings
Left Front - Stepper Motor with Lead Screw (Z0)
Left Middle - Linear Bar with Bearings/Bushings
Left Rear - Stepper Motor with Lead Screw (Z1)
Right Front - Stepper Motor with Lead Screw (Z2)
Right Middle - Linear Bar with Bearings/Bushings
Right Rear - Stepper Motor with Lead Screw (Z3)

Rear Middle Left - Linear Bar with Bearings/Bushings
Rear Middle Right - - Linear Bar with Bearings/Bushings

Or putting Linear Bars with Bearings/Bushings next to each leadscrew Mounts?

Or putting the linear bars with Bearing/Bushings on the extreme corners and putting the leadscrew mounts next to each linear bar mounts?

What would be the best? (sorry being very wordy...)

otaku521

or go with 6? 4 on the sides and 2 in the rear?

dc42

I haven't built a CoreXY machine, but the most common configuration seems to be:

Linear rails left middle and right middle
Leadscrews front left, front right, and rear middle

Getting 2 linear rails exactly parallel to each other is difficult enough, 3 or 4 would be worse.