The Effect of Particle Pollution on the Temperature Rise of Assembled Printed Circuit Boards

Abstract

During the long-term operation of electronic devices, airborne dust particles are carried by airflow into the interior of the equipment, where they deposit on the surfaces of printed circuit boards (PCBs) and their assembled electronic components. This deposition obstructs normal heat dissipation, thereby increasing the risk of component failure. To investigate the effect of dust accumulation on the temperature rise of PCBs with integrated electronic components, this study proposes an innovative thermal modeling approach by treating deposited dust as an equivalent porous medium film. Gradient-density quartz particle deposition experiments combined with image recognition techniques were employed to determine the porosity of the dust layer. Based on thermal resistance theory analysis, the equivalent thermal conductivity of the film was derived. A finite element method (FEM)-based thermal simulation model was developed to systematically study the influence of dust coverage density on the surface temperature of PCBs assembled with various power levels of electronic components. The simulation results were experimentally validated through quartz particle deposition and temperature rise measurements. Experimental results indicate that the surface temperature of the circuit board increases significantly with higher particle coverage density. As the dust coverage density increases from dust-free condition to 1200 $\mu $ g/cm², the predicted temperature rise of PCB-mounted chips is an average temperature rise of $3.6~^{\circ }$ C, showing excellent agreement with experimental measurements, with an overall deviation within −3% $\sim\!+4$ %. Under the same coverage density, the temperature rise is nearly identical across electronic components with different power ratings. Finally, a theoretical temperature rise model for dust-covered components was established by fitting experimental data. This study demonstrates that modeling deposited particles as a porous medium film provides an efficient and accurate method for predicting the permissible dust coverage threshold of electronic products based on allowable temperature rise limits.