February 12, 2018 by webadmin

Selective Soldering: Through-hole Technology on PCB’s

As surface-mount technology (SMT) becomes more and more popular, there is a corresponding reduction in the need for through-hole technology on printed circuit boards. However, there’s no getting around the fact that specific through-hole pins are still needed, and that means there is still a need for them to be soldered. While this can be done by hand, it takes longer and can introduce quality issues, and in an industry where quality is paramount, there’s simply no room for subpar production.

That’s where selective soldering comes in. The fact that this kind of through-hole soldering is often done by a programmable machine vastly reduces the potential for any kind of quality issues to creep into production, and it’s much more cost-effective as well. With selective soldering, delicate surface-mount packages can be left undisturbed, while targeting only those areas on the PCB where through-hole soldering is required. The result is far less defects, greater throughput, and a bottom line which boasts significantly lower costs.

When Selective Soldering is Indicated

Selective soldering becomes an important process when it’s necessary to solder components on PCB’s that might be harmed by the heat generated in a reflow oven, or in the process of wave soldering used either in surface-mount technology or through-hole technology. Generally during the surface-mount reflow process, a number of solder joints have already been emplaced, and the more delicate solder joints are left to the selective soldering process. This calls for considerable precision, both to install the delicate new solder joints, and to avoid damaging any of the previously soldered joints which may surround those selective sites.

ADCO Selective Soldering

As practiced at ADCO Circuits, selective soldering is accomplished by ERSA machines which can address either both sides of the printed circuit board, or can focus on a small number of through-hole components. These programmable machines eliminate many of the errors which might otherwise result from hand soldering, or from wave solder pallets. These ERSA machines are highly capable, and can deliver point-to-point soldering that qualifies as a Class 3 solder joint, without the need for a robot dedicated to the process.

The modular design of these ERSA machines promotes greater machine accuracy, more potential for modular extensions, increased throughput, and at the same time, a decreased floorspace footprint – all of which contributes to the cost-effectiveness of the ADCO selective soldering process. With modular components that have been optimized for fluxing, pre-heating, and the soldering phase itself, the ERSA machine approach is a marvel of efficiency and quality production in the field of selective soldering.