Metals and other hard materials are cut by adding an abrasive in powder form to the water stream. With this method, called hydroabrasive machining or abrasive jet machining, the abrasive particles (often gamet) are accelerated by the water and accomplish most of the cutting. Higher flow rates of water are required to accelerate the abrasive particles.
Materials are cut cleanly, without ragged edges (unless the traverse speed is too high), without heat, and generally faster than on a band saw. A narrow, 0.8 to 2.5 mm (0.030 to 0.100 in.), smooth kerf is produced. There is no problem of thermal delamination, or deformation, when water jet cutting is properly applied.
The wide application range and lack of beat are the major advantages of water jet cutting. The versatility of the process is demonstrated by the simultaneous cuts through carbon steel, brass, copper, aluminum, and stainless steel shown in Figure W-1.
Water jet and abrasive water jet systems compete with such processes as band saws, the reciprocating knife, flame cutting, plasma, and laser cutting. They can handle materials that are damaged by heat from thermal processes, or materials that gum up mechanical cutting tools. In some cases, they can cost effectively replace three operations: rough-cutting, milling, and deburring of contoured shapesl. The wide range of materials which may be cut appears in Table W-1.
