Georgia NOCTI Engineering & Technology Practice Exam

Garnet is commonly used as an abrasive material in Abrasive Water Jet (AWJ) cutting due to its effective cutting performance and desirable physical properties. It is a naturally occurring mineral that can withstand high pressures and offers a sharp cutting edge, which enhances the cutting efficiency when mixed with water and pumped at high velocities.

This mineral is preferred because it is relatively inexpensive, environmentally friendly, and produces minimal dust compared to other abrasives. Garnet's hardness ensures that it can cut through a variety of materials, including metals, composites, and ceramics. Its angular shape contributes to effective cutting by creating a more focused and penetrating jet stream.

In contrast, other materials such as sand and crushed glass may not provide the same cutting effectiveness or may produce an excessive amount of dust, making them less suited for precision cutting applications. Aluminum oxide, while an abrasive, does not have the optimal characteristics that garnet possesses for AWJ systems, particularly regarding hardness and the ability to maintain performance under the specific conditions of water jet cutting.