Surface Mount Technology vs Through-Hole Technology

In the electronics world, PCBs have been major hardware that helps in electronics manufacturing. The two primary techniques used in PCB Assembly are Surface Mount Technology (SMT) and Through-Hole Technology (THT). We will be discussing a thorough difference and comparison between these two technologies. 

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Through-Hole Technology: The Tried and True

With roots reaching back to the 1940s, Through-Hole Technology (THT) is akin to a wise elder statesman within the realm of PCB Assembly. It’s a time-tested technique that has reliably served the electronics industry for decades. Emerging in an era where electronics were just beginning to take hold of human civilization, THT has undoubtedly played an instrumental role in propelling us into our technologically-driven present.

The Process of THT

Anchoring the uniqueness of Through-Hole Technology are the through-hole components. These components are equipped with leads, protruding metal wires that are designed to be inserted into holes pre-drilled into the PCB. The leads extend through the PCB and are soldered securely onto the opposite side.

This method of assembly provides solid mechanical and electrical connections. The very act of the leads penetrating the board and being soldered on the other side creates a physical bond that can withstand a good deal of stress. It’s this robustness that ensures a consistent and stable operation of the assembled device, even when subjected to rough conditions or vigorous usage.

Weighing the Pros and Cons of THT

One of the standout strengths of THT is its high durability. This makes it an ideal choice for assembling components that will be exposed to substantial mechanical stress or operate in extreme environmental conditions. Moreover, THT is also the preferred assembly technique during the prototyping phase. 

However, the very features that give THT its strengths can also create challenges. For starters, the need to drill individual holes for each component’s lead translates to a more labor-intensive process and in turn, increased production costs. Manual soldering of leads also demands skilled labor, which adds to the cost. Since through-hole components require real estate on both sides of the board, the maximum density of installed components is reduced, and the PCB design is less space-efficient as a result.

Surface Mount Technology: The Compact Powerhouse

In response to the limitations of THT and the escalating demand for miniaturization and efficiency in electronics, Surface Mount Technology (SMT) was conceived. This innovative approach to PCB Assembly was a game-changer, introducing a new paradigm in the way electronics were manufactured.

The Process of SMT

Surface Mount Technology radically simplified the assembly process by eliminating the need for leads and holes. Instead, Surface Mount Devices (SMDs) are positioned directly onto the surface of the PCB. Once in place, these tiny components are soldered onto the board, securing them while simultaneously establishing electrical connections.

This method enables a significantly higher density of components to be packed onto a single PCB. With SMT, electronics manufacturers could now dream of designing smaller, more sophisticated, and feature-rich devices without sacrificing performance or efficiency.

Time Pros and Cons of SMT: A Closer Look

The ability to miniaturize components is perhaps the most significant benefit brought by SMT. Since SMT allows for component mounting on either side of the PCB, circuit density is greatly increased. In addition to spatial efficiency, the SMT assembly process is largely automated, which boosts accuracy, accelerates production speed, and enhances cost-effectiveness.

Despite its numerous benefits, SMT isn’t always the perfect solution. The small size of SMT components and their surface mounting approach means they aren’t as robust as THT components.

PCB Assembly

The Best of Both Worlds: Embracing Mixed Assembly

While both THT and SMT have distinct advantages and drawbacks, they are not mutually exclusive. Mixed Assembly is a process that integrates both SMT and THT methods in a single PCB assembly procedure. This combined strategy takes advantage of the best features of both approaches to create a solution that is both comprehensive and economical. With Mixed Assembly, electronics manufacturers are no longer bound by the constraints of using just one assembly method, and instead, they can leverage the best attributes of both worlds.

Optimizing Component Placement with Mixed Assembly

A significant aspect of Mixed Assembly lies in understanding where and when to use THT or SMT. High-stress components, or those that are likely to be subjected to rough handling or extreme environmental conditions, are generally attached using THT. This is due to the enhanced durability and robustness that Through-Hole connections offer, ensuring these components remain firmly in place despite rigorous use.

On the other hand, SMT is utilized for components that don’t require such stringent mechanical strength. Surface Mount Technology’s ability to enable a higher density of components on the PCB proves advantageous here. By employing SMT for these components, we can save valuable board real estate, allowing for a more compact and efficient design. This also translates into cost reduction, as fewer materials are required, and assembly can be expedited.

Balancing Cost, Space, and Durability with Mixed Assembly

The crux of Mixed Assembly is creating a fine balance, addressing the cost, space, and durability requirements of an electronic device. With THT and SMT working in synergy, Mixed Assembly allows for the creation of robust, durable devices that can stand up to high-stress situations without sacrificing the need for compactness, cost-effectiveness, and sophisticated design.

Bottom Line

As we’ve explored, both Surface Mount and Through-Hole Technology offer unique advantages in the world of PCB Assembly. But leveraging these advantages to create high-quality electronic devices requires expertise, precision, and industry-leading technology. That’s where FX PCB comes into play.

FX PCB is a leader in PCB Assembly, delivering reliable, high-quality solutions tailored to your unique electronics manufacturing needs. We pride ourselves on our ability to provide expert guidance and deliver top-tier PCBs, regardless of the assembly technique required. Our team of experienced professionals and state-of-the-art equipment ensures that we can handle any project, be it THT, SMT, or even Mixed Assembly.

With FX PCB, your project is in expert hands. Contact us today to get started!

Peter Gong
Peter Gong

I am Peter Gong. I have been working in PCB and PCBA industry for 15+ years now. I have been a part of the PCB revolution with my dedication to circuit board technologies and creative ideas. I write in FX PCB to impart my knowledge on PCB and PCBA for all circuit board lovers, manufacturers, and users.