The majority of PCBs produced today use Surface Mount Technology SMT whereby the components are mounted directly onto the surface of the PCB. SMT, adopted in the 1980s, has massively reduced the costs of manufacturing because it allows for far greater levels of automation. SMT components are much smaller and hence a much higher number can be fitted onto the board allowing for much denser, smaller PCBs with a higher performance. Does that mean that Through Hole Technology is dead?
Far from it. THT technology and through-hole components have certain characteristics that will keep the technology relevant well into the future:
- High powered boards need transformers, capacitors and inductors to transfer energy and the size of these components is relative to the amount of energy they can store.
- Connectors that will undergo environmental or mechanical stress, such as connectors that will have cables continually connected and disconnected, are likely to be through hole to be able to withstand that stress. Through hole components are held in place by the pins as well as the solder so have a far stronger bond with the board.
- Because of the stronger bond with the board, through-hole technology is often more reliable and is therefore used in military and aerospace products where any type of board failure is not an option and the PCB and components may experience extreme environments.
- Through-hole components are easier to access and are therefore useful in test and prototyping applications where they can be readily replaced, changed and adjusted.
- Not all types of component are available as SMD packages or are very expensive. Though the manual manufacturing process for THT components is more expensive, through-hole components can be more economical.
Find out more about Mek THT Automatic Optical Inspection equipment (AOI).