Analysis of Printed Circuit Boards strains using finite element analysis and digital image correlation

Abstract

This paper investigates the use of digital image correlation (DIC) and finite element analysis for strain measurement on Printed Board Circuits (PCBs). Circuit boards (PCBs) are designed to mechanically support and electrically connect an electronic component assembly. Due to screw assemblies, the surface level differences on which the PCB is placed, the process of assembling the electronic components induces a certain state of stress and deformation in the PCB. The main components affected are microprocessors due to the way they are glued to PCBs with BGA-Ball grid arrays (BGA). Digital Image Correlation (DIC) is a full-field contactless optical method for measuring displacements and strain in experimental testing, based on the correlation of images taken during test. The experimental setup is realized with Dantec Q-400 system used for image capture and Istra 4D software for image correlations and data analyses. The maximum level of the obtained strain is compared with the allowable limit. Finite element analysis (FEA) is a numerical method of analysis for stresses and strain in structures of any given geometry.

A Systematic Analysis of Printed Circuit Boards Bending during In-Circuit Tests

“…All these variables need to be taken into account when creating an FEM of a PCB, regardless of the type of study that is being conducted. There are many authors modelling PCBs as a full single material body [2,[5][6][7][8]10,12,13,17,18,20,21]; however, to obtain more accurate results, some researchers According to the referential in Figure 6, sensor 1 measures the strain in the Y direction and sensors 2 and 3 measure the strain in the X direction. It is possible to observe that sensor 1 is located above a region of the PCB where there are copper traces perpendicular to the sensor measurement direction in the third layer.…”

“…All these variables need to be taken into account when creating an FEM of a PCB, regardless of the type of study that is being conducted. There are many authors modelling PCBs as a full single material body [2,[5][6][7][8]10,12,13,17,18,20,21]; however, to obtain more accurate results, some researchers have opted to create multi-layered models considering the layers of the PCBs [3,11,19,20,22].…”

“…Several studies have been performed to analyse mechanically the bending effects on PCBs. The greatest number of works have resorted to three-and four-point bending tests, and are addressed to the packages' solder joints reliability and their main failure mechanisms [2][3][4][5][6][7][8][9][10][11]. There are also studies using drop-impact tests to understand the PCBs' dynamic bending effects on solder joint behaviour [12,13].…”