Circuit board production primarily uses through hole technology to attach the various components inside of an electronic device. Since the 1950s, circuit boards used point-to-point attachments to relay the impulses and messages across wire leads to the various resistors, capacitors, and diodes. The more current through hole PCB assembly method sends these leads through physical holes in the boards to make these connections. These 90 degree bent wires are soldered into place either by hand or machine.
Pros of through-hole PCB technology:
1 – Prototypes of any type of engineered mechanism can be physically changed or updated more easily with through hole PCB assembly circuit boards. Engineers have more access to the components, which makes updates and trial and error easier.
2 – Soldered lead wires connecting various components on the circuit board are stronger and less likely to experience interruption than other types of connections. This is especially important for devices that move or need to handle mechanical stressors during operation.
3 – Through hole printed circuit boards are ideal for heavier or larger components and those that have plug connections or electromechanical switches necessary for their operation.
Cons of through-hole PCB technology:
1 – More necessary production steps, such as drilling the holes, increases cost per board and also makes production time longer.
2 – Less surface area space is available for components because the holes take up some.
Surface mount technology (SMT) has been in use since the 1980s. It uses short lead wires or pins to attach various components directly to the circuit board. Although it is widely used, it does not suit all applications. Larger transformers and semiconductors that generate heat may require different options.
Most engineering and manufacturing industries used surface mount boards today. There production is easier to automate, and, after a larger initial financial investment, reduces costs per unit. IBM was one of the first international corporations to use SMT’s in computer production from the smallest home options to such complex projects as the Launch Vehicle Computer.
Pros of using surface-mount assembly:
1 – SMT’s can be made much smaller than other options, which makes them great choice for compact electronics and gadgets.
2 – Mass production of these boards takes less time and costs less per unit because there are fewer manufacturing steps.
3 – The compact size of each board and the ability to use both sides makes them neater, denser, and increases processing speed because the distance between components is shorter.
4 – Soldering is handled by reflow ovens which not only guarantees quality but also corrects component placement errors. The automated process actually pulls various components into alignment on the board.
5 – Surface mounted boards are less likely to be affected by vibration, emit low radiation, and uses connections that have lower induction and resistance.
Cons of surface-mount assembly:
1 – Repairs and updates are hampered by the small sizes and lack of access to leads.
2 – Creation of prototypes and test modules is not supported due to the rigid nature of the component attachments.
3 – The soldered leads may not withstand the high temperatures during the potting process.
With so many pros and cons of both through hole PCB assembly and surface mount assembly, the decision about which to use must be considered carefully on a case-by-case basis.