Through Hole Technology (THT)

Through Hole Technology (THT) – electronic components are mounted exit hole in the form of wires that are threaded through the prepared holes in the plates and soldered on the opposite side of the plate, also known as through hole technology (THT) and performed manually according to customer requirements, unlike SMT (Surface Mount Technology). Except wave soldering, either automatic selective soldering or hand soldering will be performed by our workers, who are experienced in related standards.


How does THT assembly work?

In conventional THT assembly, wired or through-hole components (also called THT components) are put into holes drilled into the printed circuit boards, that are then pasted to pads using a variety of soldering techniques.  These components are different with SMT components because there are wires leads to connect them through the holes on PCB, rather than placing the components on soldering paste extended on the surface of a PCB.


Even though SMT methods have obviously replaced THT, which is more expensive and labor-intensive, there are still many applications of THT in EMS market. Many cases and types of components of THT assembly are applied, including high-performance electronics (e.g. high-voltage resistors or relays), components with high mechanical stress (e.g. connectors, switches), and large components (e.g. capacitors, inductors).


After the THT components are manually placed on the PCBs, generally following three different soldering techniques will be applied:


Wave Soldering

With wave soldering, electronic components are soldered to PCBs in three steps. First, foam flux is evenly placed onto the bottom side of the boards, so that it is fully coated. Next, the flux material is activated with a preheated unit and heated up to the soldering temperature. In the typical soldering process, PCBs are then passed through a soldering wave. The solder attaches to the electronic component pins in the contact holes. After a cooling-down phase, the solder hardens and permanently attach the component to the PCBs. During the last phase, the PCBs are cooled and transfered into a washing bay, where the remaining flux material is cleaned off.


Hand Soldering

For some special cases (for example, if SMT components also have to be assembled on the same side of the PCB) when wave soldering is not possible , hand assembly will be used. Hand assembly is performed by our experienced engineers.


Selective Soldering

For multi-models production order, selective soldering enables THT electronic components to be placed on PCBs that would otherwise not be suitable for wave soldering because SMT components also need to be assembled. In such cases, we rely on partially or fully automated selective soldering processes when a defined amount of tin solder must be applied or if a specific area of the PCB must be kept free of flux material. These methods of production requirements are conventional for customers in the automotive branch.

NOD Electronics offers THT assembly, as well as device mounting and cable assembly. For inappropriate designs or assemblies, we also provide a series of SMT and BGA Rework services, regardless of where your boards are assembled. We have 2 THT lines with regular 45 staff and daily capability of 1 million spot to complete your THT assembly task. All of our positions are well-trained and experienced in THT operations. What’s more, we have regulated operation standards to highly eliminate mistakes during the THT performance.


Through Hole Technology (THT) is one of our strengths at NOD Electronics. Currently there are hundreds of customers who rely on our THT services for years. We fully concentrate on your time-to-market requirements and perform all beyond your expectations. See more services of PCB assembly or generally next stage ICT after THT.

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Address: Building E,Qixing Industrial Area,Xintang Town,Zengcheng District,Guangzhou,China 511340

Mobile: +86-1862-0101-507


Tel: +86-020-8232-4751