What is the difference between SMT technology and THT technology? What are the advantages?

SMT (surface mount technology) is a surface mount technology, which mainly includes three parts: solder paste printing, mounting and reflow soldering.

Solder paste printing is mainly to print solder paste on the PCB where you want to solder parts through steel mesh (also known as steel plate and screen)

Placement of electronic components, including resistors, capacitors, inductors, ic, BGA, QFP, etc. , through the mounter on the PCB.

Reflow soldering is to weld the previously printed solder paste with the attached parts through a reflow oven. Now it is generally lead-free process, and the high temperature is about 250 degrees.

THT technology In the traditional electronic assembly process, wave soldering technology is generally used to solder printed board components and through-hole plug-ins (THD).

However, wave soldering has many disadvantages: high density and fine spacing patch components can not be distributed on the welding surface; Bridge multi-leakage welding; Need to spray flux; The printed circuit board is warped and deformed due to large thermal shock.

With the increasing density of current circuit assembly, it is inevitable that there will be high-density and fine-pitch patch components distributed on the soldering surface. The traditional wave soldering process can't do anything about it. Generally, only the patch components on the welding surface are reflowed separately, and then the remaining plug-in solder joints are repaired manually, but there is a problem of poor solder joint consistency. In order to meet the above challenges, several new hybrid welding technologies are constantly emerging, such as selective welding, through-hole reflow welding and the use of shielding molds, which can protect surface mount components and realize the welding of plug-ins and greatly reduce the production process and cycle time.