Abrasive waterjet is an abrasive blasting machining process that uses abrasives propelled by a high velocity fluid to erode material from the workpiece.
A specialized pump pressurizes water up to 55,000 PSI. It is then forced through a diamond orifice and a carbide mixing tube where it is mixed with garnet sand. This mixture exits the nozzle at over the speed of sound. That speed is what provides the cutting force that removes material. Common uses include cutting heat-sensitive, brittle, thin, or hard materials.
The waterjet machining process is usually under water so the noise and splash back is controlled. The process adds no extra heat to the material, leaving the edge ready for a second machining operation or welding right out of the machine.