THT Assembly

The installation of electronics on PCBs is most often performed using two types of technology, THT or SMT. THT consists primarily in manual activities, whereas SMT is based on a high degree of automation. Each of these methods of electronics assembly offers certain benefits and restrictions, which also determine their purpose and applications.

THT assembly – what does it consist in?

THT is an abbreviation of the English term Through-Hole Technology. Literally, it means the technology of through holes. In Poland, this process is most often referred to as “montaż przewlekany” (literally: through-hole assembly). It can be performed in fully manual or semi-automatic mode.

THT assembly consists in implementing electronics on PCBs by putting purpose-made leads in the form of wire feet through dedicated openings. Then, the feet put through to the other side of the board are cut and the whole is soldered.

It is worth noting that THT is compliant with PCI standards – regardless of whether it is fully based on manual activities or in the semi-automatic mode. Since the THT requires great precision, it involves specialists with many years of experience. However, it should be noted that this technology entails certain restrictions related to the progressing miniaturisation. As a rule, THT-based electronic components are larger than the ones used in other technologies. For this reason, this method of implementation is found primarily in amateur equipment or other dedicated solutions.

THT soldering

THT soldering is performed manually or partially automatically. The manual process is aided by special fields made of easy-to-solder material like tin-plated copper. In turn, these fields lead to the paths on the PCB, which significantly facilitates the assembly of electronics.

In many cases, semi-automatic soldering of the individual components is possible as well. The most important technologies in this area are e.g.:

• the so-called assembly on the wave, in which the soldering is performed by means of the machine, which forms tin waves under the moving board;
• spray soldering, in which the board moves under purpose-made nozzles that spray molten tin at specific points on it.
   

THT vs SMT – most important differences?

Another form of placement of electronic components on PCBs is SMT. First of all, the difference between the abbreviations SMT and SMD should be explained. The former designates a specific manufacturing technology and the latter designates purpose-made electronic components that accompany the use of this technology.

In SMT, the assembly of electronics consists in using the so-called surface method. SMD assembly is performed by placing them on the PCB. Previously, designated points of the board is covered with brazing slurry or, in some cases, hot-setting adhesive. Then, the whole reaches the oven, where the individual components are bonded by means of temperature.

SMT and THT assembly – which technology is more efficient?

The technologies of assembly of electronic components on soldering boards depend on many factors. So, the question that could be asked is: which one is better, SMD assembly or THT assembly? The main differences between consisting in the automation degree are the sources of both their advantages and certain restrictions.

THT assembly, despite being performed manually, which translates to lower efficiency and restrictions related to the component size, offers a series of advantages. They include e.g.:

• longer life of the solution;
• tighter component adherence.

SMT assembly is becoming increasingly popular in particular due to:

• higher efficiency;
• possibility of using smaller components.

To conclude, it should be noted that each of the methods described offers its own benefits. Due to the progressing miniaturisation, SMT assembly has been increasingly gaining popularity on the market in recent years, however, THT is still present and in demand. Therefore, it can be concluded that the two technologies complement each other.