Printed Circuit Boards Surface Mount Technology (SMT) Tips


Many people don’t like to deal with surface mount technology (SMT) because of some misinformation about it. There exist several good references for commercial assembly, but not much is written about prototyping and hand soldering with SMT.

SMT is a type of electronic component package. Surface Mount (SM) is one of two categories of electronic components; the second is through-hole (TH). SM components are designed for loading and soldering on a specific side of the printed circuit board. TH is designed for loading and printing on one side of the circuit board.

Why is SMT used in industry?

SMT offers several significant benefits over though TH — including the smaller physical size with the same electrical function — are cheaper in terms of raw material, have less unwanted effects, and are faster for automatic machines to place. The most significant advantage of Surface mount PCB assembly is the real estate saved by not drilling holes through the board. That allows the board to have more trace and thus be more compact.

Why should you care about Surface Mount Technology?

SMT increasingly affects those involved in the development, repair, and modification of electronics. SMT equivalents are quickly replacing the TH components as producers increase their investment in SMT production equipment to reap the benefits.

SMT Myths

Some of these myths include the idea that SMT requires specialized training, professional PCBs, expensive special equipment, and other components that are difficult to find. Most printed circuit board assembly houses do not have any problems with SMT. Find out before you place an order.

Tip to Use SMT without Stress

To use SMT without stress, you must practice your technique, keep a steady hand, have good eyesight or use some magnification, and use a good pair of tweezers.

How can SMT help you?

SMT offers many benefits over leaded components. These include:

• SMT resistors are simple to parallel together and quick to solder and de-solder. Not working on both sides of the board at the same time reduces frustration.

• When using RF signals, unwanted effects in SMT parts are fewer than parts.

• When space is limited, SMT parts fit perfectly on the gaps of the VERO board and posses the ability to mix with designs that utilize leaded components.

• When hole drilling is an issue, SMT streamlines this because you load and solder on the same side.

Tips for soldering SMT Parts

  • Proper soldering techniques come with practice. There are also a few tips to follow, including keeping the circuit board clean, using the correct soldering iron for the job, selecting the accurate suggestions, and using solder flux. For practicing, use SMT resistors because they are not easily damaged.
  • 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.
  • 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 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.
  • 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.
  • Consider the type of solder paste and nature of the components prior to making a selection.

What parts can you recycle?

It’s possible to obtain many SMT parts from surplus or junk equipment. It saves money and allows or good de-soldering practice. Ceramic capacitors are problematic as they crack easily. Resistors, inductors and transistors can be verified for proper operation, but excessive heat may damage the device. For a list of all parts, there a couple good component suppliers. DigiKey is one of the more popular ones. You can also scavenge old computers, cell phones, TV’s, etc.