This paper presents the concept of a standard method used to determine the durability of injection molds. In particular, some Rapid Tooling molds are less resistant to abrasive plastics than conventional steel molds. Some evidence of wear in a conventional mold is given, and a specific mold is designed for this test; polymer materials are defined and the test methodology is outlined. Numerical simulation is utilized to show the areas of the mold subject to high shear stresses.