Quote Originally Posted by JestingAngler View Post
Over traveling on rapids I think. While running image to g-code cutting from left to right and rapiding back. After about 60 passes I notice that the cutter was passing the original x0 by 1/4". At first I thought loosing steps while cutting but I was only feeding at 6ipm, That's where my torque is. I'm now thinking it could be deceleration. Rapid is 60ipm. Using linuxcnc. Although my micro step is set at 1/8. Maybe I am loosing steps. Any help appreciated.
In Mach 3 you have 2 choices- Exact Stop and Constant Velocity. In Constant Velocity mode the stepper runs full speed up to the stop point, and if you are running fast rapids and have a lot of carriage inertia, the carriage can overpower the stepper and go too far. In Exact stop mode, the stepper speed begins to ramp down before reaching the end of the travel and reduces the inertia of the carriage eliminating the possible over-run.