When the rotation direction of the milling cutter is the same as the feed direction of the workpiece, it is called down milling, and when it is opposite, it is called up milling.
Up milling: The cutting effect is to remove chips from top to bottom. Features: There is a lot of friction and resistance during processing.
Features: There is a lot of friction and resistance during processing.
Down milling: The cutting action is to remove chips from the surface of the workpiece from bottom to top. Features: A. There is less friction and resistance during processing. B. Easy to clamp, no vibration, and high precision of the processing surface.