aster more economical and repeatable method to determine the gears relationship to its axis. Roll testing our molded gear at tight mesh with another gear that has the theoretically perfect gear geometry does this. During this process we can record any runout (T.I.R.) or concentricity error to determine the overall quality of the gear. This method can be automated and is very good at determining the overall quality of the gear. The quality of a gear is determined by how little runout (T.I.R.) it has and how little error there is in the tooth form. I have not mentioned how the plastic material itself plays into this equation. An engineer must always be mindful that like any plastic he may encounter non-uniform shrinkage. This may or may not meet the engineers design intent. Therefore engineers must be mindful of the capabilities of each unique material and educate themselves on the benefits and drawbacks of this material. Plastic material manufacturers are constantly developing more sophisticated engineering grade materials that have overtime been an economical alternative to metal.I hope that this brief introduction basically gives you at least somewhat of an idea of everything that is involved with producing something as seemingly simple as a plastic gear....
