The document discusses water jet machining, which uses high-pressure water to cut materials. It works by eroding material using a water jet with a small diameter nozzle operating at velocities over 900m/s. The main components are an intensifier, accumulator, oil pump, water jet nozzle, and XYZ motion controller. Water jet machining can cut a variety of materials without heat or burrs and is commonly used in industries like shoe and printed circuit board manufacturing. It has advantages over lasers such as being safer, requiring simpler maintenance, and able to cut heat-sensitive materials.