Test Methods for Plastic Gears
AGMA 946-A21
AGMA 946-A21


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


This information sheet describes test methods and recommended documentation practices for determining load carrying capacity and wear performance of plastic gears. It 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.


[The foreword, footnotes and annexes, if any, in this document are provided for informational purposes only and are not to be construed as a part of AGMA Information Sheet 946-A21, Test Methods for Plastic Gears.]

The purpose of this document is to create a framework for communicating the information collected from various types of plastic gear material test programs. Although data describing the physical performance of plastic materials used for gear applications is available, this information is not always directly related to the performance of the material as a gear. Efforts made to characterize the performance of plastic gears and gear materials have been spread among different individuals and organizations, with little uniformity in the methods used or data supplied. In many instances tests that have been designed and deemed adequate for traditional metal gearing have been used without compensating for the unique physical performance characteristics of plastics, resulting in data that is limited in its usefulness.

The document outlines typical test configurations, suggest formats for presenting the data, and includes some recommendations and cautions peculiar to plastic gears.

The first draft of AGMA 946-A21 was created in October 2014. It was approved by the membership in February 2021. Suggestions for improvement of this standard will be welcome. They may be submitted to


The following documents contain provisions, which, through reference in this text, constitute provisions of this information sheet. At the time of publication, the editions were valid. All publications are subject to revision, and the users of this information sheet are encouraged to investigate the possibility of applying the most recent editions of the publications listed.

AGMA 909, Specifications for Molded Plastic Gears

ANSI/AGMA 1106, Tooth Proportions for Plastic Gears

Pages: 18

ISBN: 978-1-64353-091-8

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