Been machining for almost 20yrs and now trying my hand at some basic 3d milling just to try something new. Im 3d milling some plastic right now and not getting the surface results im after. I am ball milling a varying radiused outer surface with a finish DOC of .0002" for finish pass after a rough pass leaving .01". The finish just isnt smooth, machine lines are rough. Only place where the finish is like glass is on a steep radius that gets cut with the side of the ball, the rest of the part thats cut with more of the lower end of the ball is not good. Im climb milling on the surface with a chip load of .004" at 4500RPM on a 1/2" ball. My toolpath is basicly making a spiraling cut all the way around the part and then stepping down Z-.0002" and making the next cut around.
So would i get a better finish using a zig zag style toolpath on X or Y and using Z axis to do the 3d machining, versus spiraling type machining with XY moves at a fixed Z depth per pass? Or are there some other 3d basics that im just overlooking? What are a few basics that are must knows to get started with 3d machining?