A new method was developed to decrease the amount of thermal damage on the contact surface of a plastic gear tooth. The main aim of this method is to decrease the amount of thermal damage on the tooth surface by reducing the heat accumulated in the tooth under working conditions. For this reason, air-cooling holes on the plastic gear tooth were drilled in different locations, with the intention of lowering the tooth temperature by transferring the heat away from the tooth through these holes via convection. Using three the different configurations of holes, the air and temperature at the tooth contact zone were measured and compared. © 2010 ASM International.