Nontraditional manufacturing (NTM) processes are those processes that remove material by: chemical reaction, electrochemical action, and thermal action. The chemical machining processes include those wherein material removal is accomplished by a chemical reaction, sometimes assisted by electrical or thermal energy applications. This group includes chemical milling, photochemical machining, and thermo chemical machining. ECM, also called electrolytic machining, removes metal essentially by deplating. Thermochemical machining is used as a secondary operation to remove burrs and fins from parts after they have been either cast or machined. It can be done by either a combustion process or by chemical spraying. The use of a high-pressure jet of water to cut materials is an emerging technology worth consideration in many manufacturing scenarios. Called waterjet cutting, waterjet machining, or fluid machining, this process employs a high pressure pump or intensifier to pressurize water up to 379,201 kPa (55,000 psi) and force it at two to three times the speed of sound through sapphire nozzles onto extremely small areas.