What is the difference between three-axis machining and four-axis and five-axis machining in UG programming?

The 3-axis machine can only process one surface, that is to say, a mold with low requirements will do, because there is a problem that the central linear velocity of ball end mill is zero. 4-axis machine can process box-shaped parts, and the mold processing range is wider. The 5-axis machine tool can process very complicated parts such as blades, and all positions can be processed as long as the tools do not interfere.