Ballscrews v. acme screws

[Swarfing]

Jonathan consider this telling off.....You are far too technical for your own good sometimes, this is a hobby site for a lot of people and "Captain i just cana get fix"

:-) :-) you uni boys will learn much more once you are in the real world...LOL!


PS

It is not a real telling off, just trying to slow you down a bit

[russell]

Jonathan consider this telling off.....You are far too technical for your own good sometimes, this is a hobby site for a lot of people and "Captain i just cana get fix"

:-) :-) you uni boys will learn much more once you are in the real world...LOL!


PS

It is not a real telling off, just trying to slow you down a bit

Take no notice Jonathan. An engineering degree is a great start. Of course you will learn more later. It is much more difficult to start with the practical skills and learn the theory later!

If possible take a year out during the course to get industrial training. You will have much more to offer a potential employer.

Back to the topic:
Your quote "True, but that cannot apply in out (sic) case as we use step/dir drivers which can only ever be commanded to move one micro-step at a time" is not quite true.

Consider the case where the motor is stationary and you try to move it one microstep. If the torque when microstepping isn't sufficient to overcome the friction the motor stays where it is. You now try to move it another microstep. Now the torque produced by the motor is increased (almost doubled for fine microstepping). Each microstep asked for increases the torque (up to a maximum of 70% of the full step torque) until the motor is able to rotate. The positioning may thus lag behind the desired position by several microsteps.

Russell.

P.S.
The drive waveform is only sinusoidal during continuous motion.