Micro steps

[Neale]

At a purely mechanical level, as A_Camera says, micro-stepping can give smoother movement. No micro-stepping and a stepper sounds like marbles in a cement mixer. However, because MS uses the balancing of currents between sets of coils in the motor rather than using full current in one coil (full-step positions), the torque available is reduced. In practice, some MS is used and the general recommendation is somewhere around x8-x10, giving 1600-1800 positions per revolution. Note that this is done for smoother movement and does not necessarily give you a corresponding improvement in position accuracy as the MS positions aren't quite as well-defined as full step positions.

There's another factor, though, and that's your motion control system. Say you are aiming at a max stepper speed of 600rpm (that's a bit slow generally but makes the sums easier!) So, 600rpm is 10 revs/sec. Full stepping means you need 180x10=1800 pulses per sec, well within the capabilities of even a parallel-port system. At x8 MS, that becomes 8x180x10pps, 14400pps, which is starting to push things a bit. At a realistic 1000rpm, that's 24Kpps, which is probably beyond a parallel-port system. That's one reason why people use external motion controllers these days - can deliver higher pulse rates to match realistic machine speeds and the more accurate pulse timing also helps smoother motion.

[erniehatt]

At a purely mechanical level, as A_Camera says, micro-stepping can give smoother movement. No micro-stepping and a stepper sounds like marbles in a cement mixer. However, because MS uses the balancing of currents between sets of coils in the motor rather than using full current in one coil (full-step positions), the torque available is reduced. In practice, some MS is used and the general recommendation is somewhere around x8-x10, giving 1600-1800 positions per revolution. Note that this is done for smoother movement and does not necessarily give you a corresponding improvement in position accuracy as the MS positions aren't quite as well-defined as full step positions.

There's another factor, though, and that's your motion control system. Say you are aiming at a max stepper speed of 600rpm (that's a bit slow generally but makes the sums easier!) So, 600rpm is 10 revs/sec. Full stepping means you need 180x10=1800 pulses per sec, well within the capabilities of even a parallel-port system. At x8 MS, that becomes 8x180x10pps, 14400pps, which is starting to push things a bit. At a realistic 1000rpm, that's 24Kpps, which is probably beyond a parallel-port system. That's one reason why people use external motion controllers these days - can deliver higher pulse rates to match realistic machine speeds and the more accurate pulse timing also helps smoother motion.

Thank you, By external motion controllers, do you mean external drivers like DM 542 's