Tolerance optimization of statically under- and over-constrained assemblies (TolOpt)
Third party funded individual grant
Acronym: TolOpt
Start date : 01.08.2018
End date : 31.01.2021
Extension date: 30.04.2021
Project details
Scientific Abstract
Although products which are manufactured in series seem to be equal, every single product has individual geometric deviations, which influence the function as well as the perceived quality of the costumer. Technically acceptable deviations are restricted within the tolerance synthesis so that demanded product requirements are fulfilled. True to the motto “as narrow as required, as wide as possible” tolerance specification is always a tight-rope walk, since unnecessary small tolerances increase the manufacturing costs. In this context, the tolerance synthesis focuses on tolerancing parts at given boundary conditions so that both technical, as well as economic aspects are achieved at the best.
To solve this conflict different methods for tolerance synthesis have been developed in the recent years. However, these methods have some shortcomings. For example, there are no strategies how to handle statically under- or overdefined assemblies. This is a disadvantage since parts are regularly statically under- or overdefined assembled. Furthermore there remains a need for research, since existing approaches do not offer the possibility for simultaneous tolerance optimization of several Functional Key Characteristics. A Methodology for tolerance-optimization of statically under- or overdefined assemblies with several Functional Key Characteristics is going to be developed as part of this research project. This objective is achieved by investigating the influencing factors on the static determinacy of a system. Special attention is paid to the interaction of different influencing factors. Then methods for statistical tolerance synthesis of statically under- and overdefined assemblies are developed and applied on case studies. The scientific challenge lies in mathematical adequate description of the influencing factors and their interactions so that a tolerance optimization can be performed by using suitable algorithms. Subsequently the developed methods are expanded for assemblies with several Functional Key Characteristics so that tolerance-optimization for the entire assembly can be done simultaneously.
The results of this research project are thus verified methods, that allow tolerance optimization for statically under- and overdefined assemblies with several Functional Key Characteristics. By Using these methods time consuming and costly iterations can be avoided since tolerances are allocated best at the beginning of the product development process.