well i was talking 6al-4v, that is what we use in the aircraft world.
the trick is to cut it like it's aluminum, huge over steps, deep depth of cut and a thick chip, just at 1/10th the feed and speed, also climb milling helps the cutting edge dig into soft material that hasn't been work hardened by the flute before it.
of coarse not all of that really applies when you etch something. big thing is removing chips while you cut, fadals have a pretty week coolant pump and that is the biggest problem i've had on Ti.
and i don't know about your machine but fadals slowdown in the corners, they practically stop, unless you put it in G8 mode, where it doesn't monitor the position, just the feedback built into the servo controlers. if the table slows down and you cut too thin a chip it instantly work hardens and there goes the cutter. never use type of feed optimization, a thin chip in a corner is worse than driving the cutter through excessive material.