Production soldering techniques that persist on the shop floor each have their own unique advantages. For complete board assemblies with standard joints and built-in volume, convection reflow is a perennial choice. For through-hole joints, the solution is wave soldering. A relatively small number of solder joints may justify robotic or human hand soldering, but another soldering technique that seems to be gaining prominence is laser soldering.
The advantages of laser soldering can be substantial, offering selective soldering, noncontact heating, localized thermal control, and access to joints that would otherwise be challenging for soldering irons, wave systems, and conventional reflow. But joint geometry, materials, optical absorption, and production economics must all align to maximize the technology.
Still, why is laser soldering getting so much attention? It could be because rising board complexities are making it a requirement. Densely populated boards are more likely to have solder joints that cannot be reached by other well-established methods, such as wave soldering. Complexity also raises the possibility of conflicting heat requirements across the board. For example, connectors, plastic housings, and heat-sensitive components may make convection reflow a yield-crushing option. If only there were a way to deliver higher soldering temperatures in a precise, no-touch way, just to the spot where it’s required. Laser soldering equipment manufacturers will tell you they have the answer.
At the heart of the system, naturally, is a laser beam focused on the solder joint, which absorbs the light and converts it into heat until the solder melts and forms the wetted joint. The soldering energy is applied precisely, heating only the solder joint; no other adjacent components experience any significant heat from the process.
To continue reading this article, which appeared in the October 2026 SMT007 Magazine, click here.