ThreeBond 2217H

Surface Mount Adhesive (SMA) is a process used in electronics manufacturing to secure surface-mounted components (SMDs) to printed circuit boards (PCBs) before soldering. Unlike through-hole components, surface-mount devices are placed directly on the surface of the board, which requires precise alignment and stable adhesion during assembly.

The SMA process begins with the application of a small amount of adhesive to the PCB pads or directly onto the component’s contact points. Once applied, the component is carefully positioned onto the adhesive. At this stage, the adhesive serves as a temporary fixture, holding the component securely in place while subsequent processes, such as soldering or reflow, are carried out. The adhesive then cures, either through heat or chemical reaction, forming a strong and durable bond that ensures the component remains fixed during both assembly and long-term use.

For a sealant to be effective in SMA applications, it must exhibit several key properties. It needs to provide high adhesion to a variety of substrates, including metals, ceramics, and PCB laminates, to prevent any movement or misalignment. Thermal resistance is crucial, as the adhesive must withstand the high temperatures of soldering processes, without degradation. In addition, mechanical strength is essential to maintain component stability under vibrations, shocks, and other mechanical stresses encountered during both manufacturing and device operation.

Precision is also vital in SMA processes. The adhesive must allow for controlled dispensing in very small volumes to avoid overflow, bridging between pads, or contamination of sensitive components. It should cure cleanly without outgassing or leaving residues that could compromise electronic performance. 

One-component epoxies like ThreeBond TB2217H are specifically formulated to meet all these demands. They offer a reliable, easy-to-apply, and thermally stable solution for SMA processes, simplifying manufacturing, improving placement accuracy, and providing long-term mechanical and thermal stability for sensitive electronic components.