Quote Originally Posted by JAZZCNC View Post
How meny times have you cut this.? If you have cut it a few times did it happen in the same place.? If not then try again and see if it happes in same place.

If it does then I very much doubt it's missed steps due to Accel etc or slipping as I would expect this to be more random and not really repeatable. This would more indicate to me you have a tight spot on the Z axis making it miss steps in the same place.?

If it's random then yes go for lowering the Acceleration.

It could also be electrical noise.!

well the result's are in and after a painful day yesterday It looks like I have a tight spot on my z-axis as the ribbing is more or less in the same place.

I cut my samples with a slower feed rate and spindle speed and with a 5% step-over and a extra finish pass at 90 degrees to the first finish pass
this was all futile as I finished with the same results as all the other times.I will check the machine for lose nut bolts and tighten up my belts and put a little bit of oil on the ball screw and then try again.

A very frustrated, unhappy and discouraged James. I could just cry at this moment

but on a positive flip of the coin I only have until Christmas to get this right, sooner would be better though

James