In order for gears to achieve their intended performance, life
and reliability, the selection of a suitable gear material is very
important. High load capacity requires a tough, hard material that is
difficult to machine; whereas high precision favors materials that are
easy to machine and therefore have lower strength and hardness ratings.
Gears are made of variety of materials depending on the requirement of
the machine. They are made of plastic, steel, wood, cast iron, aluminum,
brass, powdered metal, magnetic alloys and many others. The gear
designer and user face a myriad of choices. The final selection should
be based upon an understanding of material properties and application
requirements.