The advancement of printed circuit boards (PCBs) has made them a critical, compact, and efficient component of automobiles, machines, electronic devices, computing terminals, and other electronics. PCBs can connect a solitary electronic component with the entire electronics design, enabling the device to function, has led to their widespread usage. The circuit and components mounted on the PCB must be flawless for the device to function properly. Considering the PCB design and its complexity, the number and type of components, and so on, different techniques are used to mount these components and form a functional printed circuit board assembly. The most widely used techniques are through-hole and surface mount assemblies (SMT). The selection of either through-hole assembly or surface mount assembly plays a critical role in terms of component packages, manufacturing efficiency, cost, and more. In fact, the two technologies are even being combined to get the best output. Thus, it is important to know how they differ.
This is one of the most popular and economical methods of electronic assembly. This method makes connections through the holes in the circuit board. One advantage of through-hole assembly is that the components are securely mounted onto the PCB and are less likely to be dislodged during handling or transportation. Additionally, because through-hole components are larger, they can handle more power and are less likely to fail due to heat than surface-mount components.
Surface Mount Assembly
Surface mount assembly is a more modern and easier way to assemble electronic components on a PCB than the through-hole assembly. The components are mounted directly onto the surface of the PCB rather than being inserted into holes. The components are held in place by soldering the leads to the pads on the PCB. Surface mount components are smaller; thus, they can be placed closer together on the circuit board. The surface mount assembly process is automated which helps reduce the overall assembly costs.
Differentiating Between Through-hole Assembly and Surface Mount Assembly
Here are some important pointers to help differentiate between these two PCB assembly techniques:
- Component Mounting: In a through-hole assembly, components are mounted by inserting their leads into holes drilled in the PCB. The leads are then soldered to the opposite side of the board. In contrast, in surface mount assembly, components are mounted directly onto the surface of the PCB rather than being inserted into holes.
- Component Size: Through-hole components are typically larger than surface-mount components. This is because they need to be big enough to fit into the holes on the PCB. Surface mount components are smaller and are ideal for small-sized boards, allowing for more complex circuit designs in a smaller space.
- Assembly Process: Through-hole assembly is a manual process that requires a soldering iron to attach the components to the PCB. This makes the circuit board larger and expensive. Surface mount assembly is an automated process involving specialized equipment such as a pick-and-place machine and a reflow oven.
- Reparability: Through-hole components are easier to repair or replace, while surface mount components require specialized equipment, such as a reflow oven or hot air gun, to remove and replace them.
- Reliability: Through-hole components are more reliable as they are securely mounted on the circuit board. They fit in well and are resistant to heat and other environmental parameters.
- Space and Weight: Surface mount assembly is better for applications requiring smaller and lighter devices, while through-hole assembly is suitable for applications requiring high power, mechanical strength, and prototyping.
Comparison of Characteristics
Surface Mount Assembly
Components are mounted by inserting their leads into holes drilled in the PCB
Components are mounted directly onto the surface of the PCB rather than being inserted into holes
Typically larger components are used to fit into the holes on the PCB
Smaller components are used, allowing for more complex circuit designs in a smaller space
Manual process using a soldering iron
Automated process involving specialized equipment such as a pick-and-place machine and a reflow oven
Easier to repair or replace
Require specialized equipment, such as a reflow oven or hot air gun, to remove and replace them
More reliable as they are securely mounted on the circuit board and resistant to environmental factors
Less reliable, but newer technology and manufacturing techniques have improved their reliability
Space and Weight
Suitable for applications requiring high power and mechanical strength, and prototyping
Better for applications requiring smaller and lighter devices
Both PCB assembly techniques have advantages and limitations, and the choice between the two methods depends on the specific requirements of the device. Still, if you need clarification on which PCB assembly to select, it is always advisable to consult an expert in the industry. Suntronic has a highly skilled and experienced team that can assist you in selecting PCB assembly techniques for your applications and offer a myriad of PCB assembly services.