Design of Injection Molded Plastic Gears

This project aims at the development of a guideline for
the suitable design of plastic gearwheels, considering
function, material and technology, using a physical and
experimentally validated approach.

Plastic gears show several advantages compared to metallic gears such as lower weight, dry run capability or the potential for cost-effective mass production. However, disadvantages such as limited mechanical and thermal properties and less precision need to be compensated by constructive means. Present design methods, however, have a very limited applicability since several plastic specific properties such as viscoelasticity or damage mechanisms are neglected. By computer tomographic analysis of gears and tensile specimens a partly high difference in fiber orientation distribution becomes apparent. Hence, the transferability of material properties, determined from tensile specimens, to component simulation needs to be considered. One approach is the effective stiffness approximation using micromechanical simulations to adjust the material properties, determined by tensile tests, towards the fiber orientation distribution of the gear, or to estimate and assess the resulting stiffness difference. Beyond mechanical properties the multi physics simulation requires a comprehensive tribological characterization of dry and lubricated runs.

Field of competence

Industry sectors

Project status

  • Archived



Stefan Schmidt

Scientific Staff Mechanical Characterization & Modeling

Telephone: +49 631 2017 274


Andreas Gebhard

Manager Tribology

Telephone: +49 631 2017 342


The project “Design of Injection Molded Plastic Gears” is funded by the Federal Ministry of Economic Affairs and Energy on the basis of a decision by the German Bundestag (funding reference 20379N).