I'm just starting to do some 3d machining. I'm sure that there's a simple solution for this but the finish on this part is faceted. It happened in all the roughing passes as well. The surface was an iges file made in Rhino.
You have to tighten up the model toler. Then in mastercam check your filter tolerance as well. I would run about a 2:1 and .0005 or tighter on my finish pass filter. Your model has to be tight also, so check that as well.