Based on an original white paper by Alpha Assembly Solutions.
Many LED lighting applications require joints soldered with cored wire, and therefore the LED industry faces a uniquely high demand for the materials employed during this type of assembly. Typically used to attach the LED engine array board and power driver board, connections made with cored solder wire spools are used in linear lighting applications to provide a board-to-board connection. For A-lamps, these cored wire spools are used to supply an electrical gateway by attaching the endcap of the Edison base.
Next to functionality, aesthetics and design are uncommonly critical to LED assembly, as solder joints are often visible in a range of lighting options incorporating the Edison base. Therefore, end caps are usually cleaned post-assembly to ensure a solder joint that is both functional and pleasing to the eye.
To augment brightness, many LED manufacturers also incorporate reflective white solder masks as an element of the production process. This practice reduces the potentially light-dimming effect of excess flux residue caused by spattering.
Telecore HF850 with SnCu Alloy
A cored wire alloy-flux combination, Telecore HF850 with SnCu alloy ensures optimal performance while providing aesthetics, spreadability, and minimal residue and odor. And, while solder spreadability and spatter are easily measured against IPC and JIS standards, aesthetics are difficult to quantify.
Using reflectivity in cored solder wire joints, Alpha has developed a method of measuring its shine against that of a standard mirror. Compared to a reference wire, Telecore HF850 SnCu is a staggering 180% more reflective when tested under varying soldering iron temperatures. These findings allow us to benchmark cored wire alloy-flux combinations and process parameters in favor of new combinations that support aesthetically pleasing joint characteristics