Measurement of some properties for material qualification in solderless assembly for electronics

An innovative method for manufacturing solderless assembly for electronics eliminates the need for the laminated printed circuit board, but uses new materials in an additive manner to obtain fully encapsulated electronic modules. To characterize the reliability of such a module, data for material properties are needed, some of which (Poisson's ratio, Young's module) are not found in the datasheets. They are necessary for calculating the natural resonance frequency of plates made by these materials. The paper presents the determination of the parameters using the Digital Image Correlation method. Two epoxy system materials were studied: Epoxylite 235SG, and MC62/W363. The determined Poisson's ratio values (0.37, respectively 0.32) fall within the general range confirmed by other measurements for this type of material. For Young's module only one reference was found, for Epoxylite 235SG: the determined value (2624.40 MPa) is close to that resulting from the graph of its variation with temperature at 298.15K (2500 MPa), this value being obtained by a Dynamic-Mechanical Analysis method carried out by the Elantas' Research & Development Laboratory from Parma.