Does C7 Ballscrew + Linear Scales = "C3" Ballscrew?
Posted: Mon Mar 10, 2025 2:03 pm
I'm rebuilding an entire VF2 from scratch and upgrading it to 5-axis.
I want to put money where it will do the most good. (Every area where I spend less, is an opportunity to spend more elsewhere.)
Of course 3 brand new C5 or even C3 ground ballscrews would be best.
I'm running Aikron linear encoders on every axis (around 0.0002 accuracy if I remember correctly).
Provided that a rolled C7 ballscrew has sufficient preload... how bad would it be to rely upon the feedback going directly from the Aikron linear encoders to the Hickory control to get the kind of linear accuracy I'd get from a C5 or C3 ground ballscrew?
I suppose this means that the Hickory control would have to "work harder" to position X, Y, and Z, because of the greater discrepancy between motor position vs table/spindle head position, resulting from a rolled C7 ballscrew's lower pitch accuracy instead of a C5 or C3 that's ground.
If I throw a budget ballscrew at a Hickory control, but give the Hickory control direct linear encoder feedback thinking it'll "make up for the ballscrew being a rolled C7", is this a bad idea? I've already purchased all the scales and the Hickory encoder expansion board some time ago, so the scales are going in regardless.
I want to put money where it will do the most good. (Every area where I spend less, is an opportunity to spend more elsewhere.)
Of course 3 brand new C5 or even C3 ground ballscrews would be best.
I'm running Aikron linear encoders on every axis (around 0.0002 accuracy if I remember correctly).
Provided that a rolled C7 ballscrew has sufficient preload... how bad would it be to rely upon the feedback going directly from the Aikron linear encoders to the Hickory control to get the kind of linear accuracy I'd get from a C5 or C3 ground ballscrew?
I suppose this means that the Hickory control would have to "work harder" to position X, Y, and Z, because of the greater discrepancy between motor position vs table/spindle head position, resulting from a rolled C7 ballscrew's lower pitch accuracy instead of a C5 or C3 that's ground.
If I throw a budget ballscrew at a Hickory control, but give the Hickory control direct linear encoder feedback thinking it'll "make up for the ballscrew being a rolled C7", is this a bad idea? I've already purchased all the scales and the Hickory encoder expansion board some time ago, so the scales are going in regardless.
. When it comes to the screw itself, it's either C7 or C5. Still, they're high-quality screws. The C rating mainly refers to the non-linearity error, which can be mapped and calibrated for accuracy. Of course, you still need proper preload in your screw.