Tips for Soldering Surface Mount Technology (SMT) Parts

When it comes to PCBs, the most commonly used assembly techniques are Surface Mount Technology (SMT), and Plated Through-hole (PTH) technique. In SMT, components are attached to pads on the board surface. On the other hand, in through-hole technology, components are inserted into holes drilled in the board.

Processes Involved in SMT

SMT involves several processes that must be carried out with precision. The following are the main steps involved in the assembly process.

  • Surface mount design
  • Solder paste application
  • Component placement
  • Soldering
  • Cleaning
  • Repair/Rework

Amongst all these processes, the step that has to be performed with extreme focus is soldering.

Tips to Successful Soldering

Good soldering comes with practice. However, by following the tips below, you can solder small SMT parts, and Integrated Circuits (ICs) precisely and successfully.

  • Prior to soldering, ensure that the board is clean and dry. It is recommended to use Isopropanol or wood alcohol to remove any oil or grease on the board. Oven dry the boards before applying solder paste.
  • Ensure that you use the right type of soldering iron to get the job done. A simple iron, cordless iron, temperature controlled soldering iron, among others, can be used to perform this task.
  • Consider the type of solder paste and nature of the components prior to making a selection.
  • Decide on the type of solder after examining your requirements. There are lead free, and leaded solders available for the job. When safety and environmental sustainability are of paramount importance, then lead free solders would be preferable. If your requirements call for fast joining of components, then leaded solders are the ideal solution.
  • Mostly, solder material would not have enough flux to make reliable joints. Consider using solder flux or cream to join SMT components efficaciously.
  • Use a good source of magnification. This is important as SMT solder joints are four times smaller than the surface mount PCB assembly . Insufficient magnification could lead to mistakes.
  • Use a special “jewelers eyepiece” when soldering. This helps you to see miniscule parts clearly, making the soldering easier.
  • Have a pair of tweezers readily accessible. The tool plays a major role in easing soldering and de-soldering activities.

The aforementioned are some of the tips recommended for soldering SMT parts such as resistors, capacitors, inductors, and transistors. Although they seem basic, the tips will help you to perform easy, precise, and successful SMT soldering processes.