[clembrant]

I am using a dual Y axis ballscrew type router. One motor is slaved to the other. I don't feel as though I am getting
the rapids I should be getting from these and was wondering if anyone had any ideas to improve performance. I am
using flex couplers and thinking they may be causing some misalignment. Any thoughts.

[ger21]

What motors, drives, power supply, ballscrew diameter and pitch?

And what are your accel and velocity settings?

[steve123]

I'm not sure they even should be coupled, but I would look at other things than how the two are coupled first. Some pictures would be useful.

There are several things that add together to give slow rapids. Stepper motor impedance and ball screw pitch are the most important.

What rapids are you getting?

What kind of ball screws? (Screw pitch, diameter, length)
The pitch is the most important one for rapids.
Diameter and length will give a clue about inertia of the ball screw, and thus what acceleration you can achieve.

What kind of steppers?
The impedance of the windings critical. What is it?
Oz inch?
Nema 23/34?

What stepper drivers are you using?

What power supply voltage?

An example of poor rapids would be a 5mm pitch coupled with large (>400 oz/inch, high inductance) motors, combined with poor Chinese drivers and a low voltage power supply. Large motors (large impedance) loose power at higher RPMs much faster than smaller motors, and are really only good for low RPM grunt work.

Regards,

Steve

Edit: I KNEW ger21 would jump in here. He is the stepper and rapids master.

[clembrant]

The motors are Nema 23 425in/oz. The ballscrews are 16mm x 10mm x 1150 length. The drivers are Longs DM542A . I have two 48 volt power supplies . I max out at 150 IPM rapid.and acceleration 4sec.
On my X axis which is being driven by one motor same size and set up, I am able to get 30 IPM.