RE: [CAD_CAM_EDM_DRO] Sherline CNC stepper motors getting "stuck"

> Problem #1
>
> When I try to machine a test part, I get problems with the motors
> getting "stuck"... I think desynchronized with the signals coming
> from the driver board. The motor will accelerate, get desynchronized
> and stop moving, then start moving again during the deceleration
> phase at the end of the move.

The classic cause of this problem is that your step pulse rate is too fast
for the torque required. Remember, the torque required to move the tool
while it's cutting air can be quite a bit different than the torque required
to move the tool while it's actually making chips.

> The machining is done at only 300 mm/m or about 12 inch/minute. I get
> this problem even when I just have the mill move in air (with no
> material being cut). At first, I thought that my motors were set to
> go too fast, but I can set my motors to jog at 25 ipm, yet I still
> get the problem when I run the G-code. Any ideas on what is the
> cause/remedy?

A simple jog will NEVER run the motor at the full speed you've selected, as
there's no time to accelerate up to it. Your move must be long enough to
allow the motors to accelerate to top speed, run at top speed, and then
decelerate to zero when you're attempting to find the max velocity.

> Question #2
>
> Since I have 6 wire motors, I set my Xylotex board to output 1/2 the
> rated current, but my motors get stuck at even the 8000 Hz step rate.
> To fix this, I tried reducing the current from the drive to less... I
> found that at about 0.73 amps, I can increase my step rate to 18000
> Hz when I jog the motors. My question is, if I reduce the current
> output on the driver, what do I gain/lose? What are the tradeoffs?

See above - jogging the motors is not a valid way of determining maximum
motor speeds.

-- Jerry