RAMP out on a Pocket

[Allen123]

When cutting metal and using a pocket feature ,many times you'll ramp in for non center cutting tools right?

Well has anyone heard of ramping out of a pocket to avoid tool marks?

Note: I am not talking about the profile finish ramp in and out.


Thank you for your feed back.

[HuFlungDung]

I doubt that ramping off along a straight side will eliminate toolmarks, but you could always program a path and try it.

Toolmarks are caused by cutter deflection (or the lack of it), as well as any tiny bit of built up edge on the corner of a tool, or other types of flute damage as well.

To minimize the tool marks, take the final finish pass at a very light depth of cut (.001") at a slow feedrate (I'm thinking 10ipm at 5000rpm). The trick is that you want to cut away all the material that the tool can reach on its path, because any sort of dwell or sudden change in cutting depth changes the deflection of the tool, causing a mismatch in the surface where the tool entered (and was heavily deflected) versus where it exited, where the deflection load was very light.

If this sort of finish feedrate slows down production too much, then try to plan the entry and exit on/in a corner so the exit is less noticeable.

[Geof]

Even when ramping it is wise to use center-cutting tools so you can ramp steeper and faster.

For coming out of a pocket without leaving a witness mark do it at a corner with a radius and program a 180 at the corner as the last move; this pulls the cutter away from the wall on a tangent and does not leave much mark. You can even do this with a heavy and fast final cut if your tolerances are wide and all you want to avoid is a cosmetic defect.