Design for assembly principles applied to deformable parts, a natural frequency based methodology for interfaces design

In this paper, a possible application of the DfA (Design for Assembly) principles to deformable parts is proposed. The efficiency of an assembly is expressed with the DfA index, which is influenced by the number of parts compared to the “minimum number of parts” and the assembly time. Deformable parts, if unsupported, can exhibit deformations outside functional limits; however, when assembled, they often need to behave like rigid parts. To achieve the necessary rigidity, a large number of constraints are added. Having a high number of anchor points between a part and the rest of the assembly induces a high assembly time and therefore a low DfA index. This paper aims to provide a methodological framework for designers to define optimal anchor point locations to achieve the desired rigidity with the minimum number of anchor points possible, thereby minimizing assembly time and maximizing the DfA Index. The procedure is based on modal analysis. Subsequent anchor points are added until the predefined rigidity measure, as the natural frequency, is reached. The procedure is validated through a simple case study and then applied to two cases derived from actual industrial applications. It is also shown how the procedure allows for an actual reduction of anchor points.