For many years, the technology behind a printed circuit board (PCB) has constantly improved to become more efficient and smaller. PCBs have become an important part of a wide range of machineries, computing devices, automobiles, appliances, and other electronic gadgets. Moreover, PCBs have a great impact on new inventions and technologies in the electronics industry worldwide. At present, the most well-known PCB assembly method is surface-mount technology (SMT). This is a huge development over the older assembly method of through-hole. Surface-mounting is now considered as the highest standard in printed circuit board assembly.
Definition of Through-Hole and Surface-Mount Technologies
Through-hole assembly method uses various components that have lead wires, which are attached to the PCB through holes. The lead wires depend of holes in a multi-layered board.
On the other hand, because of the demand for smaller-sized and lighter components, SMT was developed. This technology uses wires that are connected directly on the board surface instead of using hole-mounting.
Differences between Surface-Mount and Through-Hole Technologies
Here are some of the major things that differentiate SMT from through-hole PCB assembly:
• The most common problem in through-hole construction is spacing issues. SMT has substantially helped in solving this.
• Compared to other PCB technologies, the pin count has significantly increased in SMT.
• The components in SMT are mostly not made up of lead and are attached directly into the surface of the PCB. Through-hole components use lead wires that are connected to the wiring boards through holes.
• The through-hole components are bigger whereas SMT components are smaller. SMT can mount components on both sides of the board if necessary, so this can cause higher packing density.
• Because of its smaller size, SMT has faster circuit speed.
• The technology used in using SMT is very advanced.
Surface-Mount Technology has replaced other methods of PCB assembly. Apart from the aforementioned differences between surface-mount and through-hole technologies, here are some of the other reasons why SMT is more preferred these days:
1. Time Efficiency
Before the use of SMT, through-hole construction and the much older point-to-point construction were used, but these methods take up a lot of time since the pads would have to be attached to the frame of the board. The older methods also involve connecting wires and this does not only take longer time, but also alter the way energy is conducted across the printed circuit board. SMT resolves these issues by connecting components to the board surface rather than through-hole connection outlets. This simple advancement allows the printed circuit boards to be constructed through automation, which is really time efficient.
2. Reduces Assembly Expenses
Conventional assembly methods take longer time to produce than SMT. Therefore, the older assembly methods were much more expensive than using SMT. However, because of automation and the capacity to program the construction of a range of low-quantity printed circuit boards at the same time, SMT construction lowers down the expenses of production. Clients who are worried about the expenses must always make sure the assembly service uses automated SMT.
3. Improved Usability
Printed circuit boards that are designed for SMT construction use smaller components compared to older assembly methods. This will cause the whole PCB to be more polished and compact as well as have greater energy efficiency. These advancements make modern-day printed circuit boards to be utilized in a wider range of equipment such as smart phones, laptop and handheld computers, or devices that need a compact and flat PCB. Because of that, PCBs that use SMT have been widely accepted by various groups from Original Equipment Manufacturer (OEM) designers to electrical design engineers.
While SMT is more commonly used in PCB assembly, through-hole technology is still existent in prototype applications and testing that might require manual replacements and changes.
Attaching the components to a printed circuit board would merely require the schematic diagram.