Harder materials such as glass, ceramics, concrete and tough composites are cut by adding abrasives to the water jet during abrasive water jet machining. The addition of abrasives to the water jet enhances the material removal rate and produces cutting speeds between 51 and 460 mm/min. It is claimed that the abrasive water jet is hundred times more powerful than the pure water . It uses a low pressure of 4.2 bar to accelerate a large volume of water (70%) and abrasive (30%) mixture up to a velocity of 30 m/s. Silicon carbides, corundum and glass beads of grain size 10 to 150µm are often used as abrasive materials. AWJM cuts through 350 mm thick slabs of concrete or 75mm thick of tool steel plates at 38mm/min in a single pass. Abrasive water jet also has some limitations, which include; high noise levels, safety, low removal rates, inability to machine blind holes or pockets etc. There are also other versions like magnetic field assisted abrasive finishing processes which are mostly applied for polishing of balls and rollers.