The basic idea of oscillation cutting is to continually feed the tool edge into the cut, then retract slightly, and feed again to create a moment of air cutting so that very short chips are generated that fall harmlessly into the chip conveyor below.  This axis feed motion is synchronized with the spindle rotation which ensures repeatable and extremely predictable chip-breaking action.  In addition to eliminating the chip buildup problem, the interrupted cut reduces heat concentrated at the cutting area.