Set up three Z-axis location - M671

bernie-mix

Hey guys,

Set up three Z-axis location - M671- in RRF3 on Duet 3 MB6HC:

Which coordinates should I enter? The real ones of the leadscrews (A) or the ones where the bed actually rests (B)?

fcwilt

In theory the B locations are the best.

But during testing I have tried both A and B locations with equivalent results.

Frederick

Phaedrux

If it's a properly designed kinematic mount where the center of rotation is at the contact point between the mount and bed, use B. If it's a more rigid bed mount use A because the point of rotation is likely going to be closer to the point of force.

bernie-mix

Yes, it is a kinematic mount with ball screws. According to my logic, I wanted to use the "B" position too. Many thanks for your help

fcwilt

@bernie-mix said in Set up three Z-axis location - M671:

Yes, it is a kinematic mount with ball screws. According to my logic, I wanted to use the "B" position too. Many thanks for your help

What rests on the balls?

On my printer the left and right are v-groves and the rear is a simple spherical recess.

Thanks.

Frederick

bernie-mix

At the rear is a magnetic spherical recess, front right is magnetic v-groves (45° to X and Y axis) and front left a a plane round magnet

fcwilt

@bernie-mix said in Set up three Z-axis location - M671:

At the rear is a magnetic spherical recess, front right is magnetic v-groves (45° to X and Y axis) and front left a a plane round magnet

How did you chose that arrangement? I found that the two front points could use the same approach.

Thanks.

bernie-mix

@fcwilt
In my opinion, this is the only way the bed can expand in all directions without rotating around the spherical recess

fcwilt

@bernie-mix said in Set up three Z-axis location - M671:

@fcwilt
In my opinion, this is the only way the bed can expand in all directions without rotating around the spherical recess

Ah... So the balls are lifting the heated bed itself? If so I can understand your arrangement.

Thanks.

Frederick