Sherline CNC stepper motors getting "stuck"

Hi everyone,

I've been working on my Sherline CNC machine with Xylotex driver
board (set to 1/8th step) and 24 V power supply. My motors are 6-
wire, 2 amp/phase. I have two questions:

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 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?


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?


I would really appreciate any help on this. Thanks.