I aquired a home-brew 2 axis CNC about two weeks ago. It's taken me
some time to research steppers and drivers etc and get this thing
running. Finally after about 8 hours of sending bit sequences to the
interface I finally got it figured out.
It come with Tubro CNC, a DOS based communication program with the
interface. The interface is based on the UCN5804B drivers.
I cut my first "sample" over the weekend. All lines, manually entered
G-code. Whew! (I don't have a CNC program yet)
Straight lines cut great. Max linear speed is about 10ipm. I'm cutting
foam with a hot wire. The trouble come when I tried to cut a few arcs
and circles. As the wire round each quatrant of a circle, the steppers
slow down respectively (as they should)..... x slows as it reaches the
90 & 270 degree quadrants.... y slows as it reaches the 0 & 360 degree
quadrants. I hope this makes sense.
The trouble is, as the steppers slow they stall and begin to vibrate.
The program doesn't have a feedback from the steppers so there's no
way for corrections to be made, and we get irregular arcs/circles.
As far as I know the steppers are NEMA 42 running 5VDC. Linear
movement is through a fine threaded rod. The drivers are set up for
wave drive mode.
Any ideas? I'm going to try two phase mode the first chance I get. As
far as I know half step is at a loss of torque right?
Thanks for you're time and any info. I'll check back frequently if
there's any questions I can answer.