The use of plastic gears in drives is rapidly increasing, especially in the size range of modules 0.5 to 1.5 mm and at maximum load cycles of up to 10E6. An essential factor for operational reliability is the tooth root strength, which can be calculated according to the guideline VDI 2736. Unfortunately, this method does not take into account the visco-plastic material behaviour (non-linear elasticity, strain rate dependence) and geometric changes at the root, which means that the service life of plastic gears cannot be calculated satisfactorily. In order to obtain meaningful results for the service life, a bi-parametric service life model for POM gears was therefore developed in the previous project (Optimisation of the tooth root geometry of plastic gears), which in particular maps the speed dependency at different moments and tooth root radii. Through modelling and verification on test benches, the damage criterion could be researched. It turns out that at least two damage parameters are responsible for the service life of plastic gears: the strain in the tooth root and the visco-plastic strain energy density rate. This approach is new and significantly expands the state of the art. In this follow-up project, this approach is to be transferred to a broad application. In this process, geometric parameters (z, m, b, etc.) are varied in a predefined range, their influence on the model is determined and the model is optimised. The aim is to provide the user with a procedure (substitute model) for calculating the service life of POM gears in a defined design space for the failure mechanism of tooth root fracture.