Z axis is frustrating me *$#@$%^&
I have a situation I am at my wits end with and need some help.
I just converted my manual Sherline 5000 to CNC using HobbyCNC 200 Oz in steppers and their board.
I set it up ala instructions on Mach3(that is what I am using) and the X and Y axes are running just fine. No problem moving those axes to any dimension. Now the Z axis!!!!!! It moves down two or three times the dinemsion called out. Moving up it only moves about half of the dimension called for.( z.250 yeilds z.125 most of the time.) I added helper springs to the axis and it did not help at all. I changed to a belt drive reduction (2.2:1) and it didn't do any good. Backlash is not noticeable.
Does anybody have any idea what may be up with this axis? I really would like to be able to control by programming rather than doing it manually.
Maybe try to increase the accel time on the axis. I know on my Homemade CNC the z will lose steps if the accel is set to fast on the way up but runs fine on the way down.
What power supply are you using?
What stepping mode is the Z axis set to?
Have you tried different motors on the Z axis?