Using a technique called surface-mount technology (SMT), electronic components are mounted directly on printed circuit boards (PCBs). In the 1960s, surface-mount technology was created and became widely employed in the 1980s. Most established PCB assemblies were using them by the 1990s. Metal tabs were incorporated into traditional electronic components so that they could be mounted directly to the board surface. This was used in place of the standard wire leads, which required drilling holes to be passed through. SMT allowed the installation of components on both sides of the board, which was not possible with through-hole mounting. Using surface mounting reduces labor costs and increases production rates, allowing for more sophisticated PCB design and development.
What Distinguishes SMT From the Others?
- Components are placed right on the panel surface rather than being connected through the board’s holes using hole technology.
- In large part due to the elimination or reduction in the number of leads required in SMT production, surface-mount devices (SMDs) are smaller and lighter than through-hole equivalents.
- A higher level of automation is possible with surface mounting, reducing labor costs and increasing production rates.
- In addition, SMT offers greater flexibility in design. SMT and through-hole technology can be combined to give higher PCB capability on the same board, minimizing the requirement for several boards.
Reviewing the Advantages
- Mounting on both sides of the board eliminates the need to drill holes in the board, therefore reducing the amount of material that needs to be connected. Also, a higher component density can be reached, which means that more connections can be made per component.
- By placing more components closely together on the board, SMT allows for smaller PCB designs. This results in lighter and more compact designs made by a PCB assembly.
- A smaller board results in lower drilling costs because fewer holes need to be bored. The inter-package space will increase if the SMT functions aren’t expanded. PCB layer counts are further reduced as a result. Hence, the board’s expenses are also minimized.
- Shaking and vibration are less likely to break connections made with Surface Mount Technology.
- In combination with DFM practices, Surface Mount Technology can boost production efficiency by reducing or eliminating drilling processes as well as reducing setup times.
- Because SMT has less resistance and capacitance, RF signals are canceled out and performance at high frequencies is improved.
The following are some of the drawbacks associated with SMT:
- There are times when mechanical stress can’t be tolerated, and surface mounting isn’t sufficient. Connectors, for example, are frequently uninstalled and reattached to allow the device to communicate with external devices.
- Thermal cycling during operation or PCB manufacturing may degrade SMD solder connections.
- In most cases, SMT component packages can’t be put in sockets that allow for quick removal and replacement of defective components.
- The reliability of SMT solder joints is a worry because you normally apply less solder. Solder joint failures could be caused by the creation of voids.
ChinaPCBOne Technology LTD. is the author of this article on PCB assembly. Find more information, about PCB manufacturing.
