Understanding Thermal Gap Filler Pads, PCB Deflection, and Stress

Whitepaper Overview

Thermal gap fillers fill gaps in printed circuit board (PCB) electronic assemblies that can vary due to tolerance, preventing deformation to the board. They come in different materials with varying viscosities. Selecting the right gap filler is essential to prevent excessive stress during compression. 

This whitepaper by Fujipoly outlines the characteristics of gap fillers and how they impact PCBs, such as the compression characteristics of various types of gap fillers, from standard viscoelastic materials, to putties and form-in-place. Other essential considerations include PCB deflection, PCB and gap filler deflection, and best practices for choosing gap fillers. Fujipoly offers testing of pads of specific sizes, boundary conditions, and rates to better understand the stress created during assembly as well as the stress over time.