Analysis of Solderless Press-Fit Interconnections During the Assembly Process

Abstract

This paper deals with typical mechanical problems that are encountered in a solderless press-fit assembly process. First, the elastic-plastic properties of two types of press-fit pins and the friction coefficients of the pins in thin plated through holes are determined both experimentally and by three-dimensional finite element analysis. The elastic-plastic properties of the press-fit pins are determined by small-scale testing under three-point bending. The coefficients of friction of the pins in the through holes are successfully determined from the load-displacement relationships of the pins during press-fit assembly processes. The validity of the parameters that are determined is clarified by inserting the press-fit pins into holes of different diameters. By comparing the damaged areas of the printed circuit boards after assembly and the numerically obtained stress distributions, the failure stress of the boards is determined. Finally, both the retention force of the pins and the degree of damage to the printed circuit boards after assembly are predicted by numerical analysis.