This document describes test methods and recommended documentation practices for determining the load carrying capacity, wear performance, and other characteristics of plastic gears.

Types of tests covered

This information sheet describes test methods for plastic gears related to dynamic testing where two gears rotate against each other under controlled load and velocity, as well as static testing where a gear is held stationary while a load is applied to one or more of the gear’s features, or pulsator testing where the test gear is not rotating, but the load is pulsed repeatedly until fatigue failure occurs. Dynamic testing is generally used to determine fatigue related strength, wear, and efficiency performance. Static testing might be used to measure the yield strength, ultimate strength, creep, or impact related performance of an individual gear feature.

Exclusions

This information sheet does not provide any plastic material design stress numbers that might be derived using data collected according to the test procedures described here.

Application testing of complete actuators or gearboxes in their end use condition including accelerated testing, noise, vibration and harshness (NVH) is beyond the scope of this information sheet.

This information sheet does not define the characteristics of the gear failure that will ultimately be tested using the methods described. One observer's “failure” is another observer's “run-in”. There is no single definition of gear failure, since whether or not a gear has failed depends on the specific situation. This definition of failure is something that needs to be established by those planning the test protocol.