Differences between Through-Hole and Surface-Mount Technologies in PCb Fabrication

Over the last few years, the popularity of surface-mount technology (SMT) has grown wider. SMT is one of the methods we use in PCB fabrication. While the other method, through-hole technology, is still relevant in some applications, SMT is more preferable for many manufacturers.

You may take a few moments to try to learn about both of these methods, and you will surely thoroughly understand their main differences, unique features, and why SMT is the more preferred option than through-hole.

Through-Hole Technology

PCBManufacturers have used through-hole technology for so many years to construct almost every printed circuit board. This mounting method uses leads on electrical components that are inserted into holes. These components were drilled on the board and soldered to pads located on the opposite side. This type of technology is quite reliable because it offers strong mechanical bonds, but the extra drilling makes the PCB manufacturing much more expensive.

In addition, the holes create limitations when it comes to the available pathways for signal traces on the board’s layers, which are directly under the top layer on multi-sided PCBs. These are only two of the various reasons why SMT became really more popular than through-hole during the 1980s.

Surface-Mount Technology

As an alternative to drilling holes during PCB fabrication, SMT allows electrical components to be directly placed or mounted on the surface of the board. In general, the components we use in SMT are smaller compared to their counterparts in through-hole method. This is because SMT either uses smaller lead components or no leads at all. Since the printed circuit board of surface-mount devices (SMDs) do not involve as many drilled holes, and their components are smaller, it makes it possible for higher circuit densities on smaller PCBs. This is particularly important because the electronics today are becoming more compact and more complex. Moreover, SMT is typically less expensive compared to through-hole technology.

Main Differences

There are many differences between these two types of technology in PCB fabrication, but some of the key distinctions include the following:

  • SMT addresses the space issues common to through-hole technology.
  • Components in SMT have smaller or no leads and we directly mount them to the PCB, while components in through-hole method require lead wires that are inserted to drilled holes.
  • In SMT, the pin count is higher compared to through-hole mounting.
  • Since components in SMT are more compact, there is a much higher packing density achieved in this method than through-hole.
  • SMT allow assembly automation during manufacturing, which makes it much more preferable for production with high volumes at less expensive costs compared to through-hole.
  • SMT is usually less expensive during the PCB fabrication, but the capital initially needed for investing in equipment is higher than through-hole.
  • Because of the reduced size of PCBs in SMT, it becomes easier to have higher circuit speeds.
  • SMT requires a really advanced design, skill, technology, and production.
  • When it comes to huge, bulky components, high-voltage and high-power parts, and components that are prone to repeated mechanical stress, through-hole technology is usually the more preferred method.

There are cases wherein through-hole technology is still used in modern PCB manufacturing, but mostly, surface-mount technology is far more superior.

Choosing a PCB Manufacturer That Offers Surface-Mount Technology

The cost to buy the machinery and equipment necessary for SMT is really high, so a lot of small electronics companies are having a difficult time to benefit from this efficient method of PCB fabrication. If you are one of them, it will be in your best interest to look for a manufacturer that offers these kinds of services like www.pcbnet.com.

We can help you integrate surface-mount technology into the design and manufacturing of your printed circuit boards without the need of buying and maintaining costly machineries. We assure you that we are knowledgeable about the best and the latest technological advancements in PCB manufacturing. We also know and apply the best practices for producing complex devices.