How Does SMT PCB Assembly Differ Between Industries?
SMT PCB Assembly Differ Between Industries
In the PCB industry, there are two main methods of assembling circuit boards: through-hole technology (THT) and surface-mount technology (SMT). Through-hole components require wire leads to pass through holes on the board, while SMT uses components with small lead spaces that can be placed directly on the surface of the circuit board. This allows for much higher component density and is generally a more cost-effective method of production. However, there are some disadvantages to using SMT that can limit its usefulness in some cases.
Through-Hole Components are generally preferred for designs that prioritize mechanical strength and reliability, or that use components not available in SMT packages. This is because THT components can rely on the metal in their leads to provide structural integrity and vibration resistance to the circuit board. Conversely, smt pcb board components do not have this benefit and are more likely to be damaged during assembly or in the field due to their smaller size and less robust construction.
SMT assembly is typically more automated and efficient than THT, using pick-and-place machines for precise component positioning and reflow ovens for soldering. In contrast, through-hole assembly is often labor-intensive and slow. Highly automated lines reduce labor costs but require significant capital investment. Conversely, manual assembly, while flexible, is labor-intensive and time-consuming, leading to higher costs. Labor costs vary significantly by region. Manufacturing in countries with lower labor costs can reduce expenses but may involve trade-offs in terms of quality and lead times.
How Does SMT PCB Assembly Differ Between Industries?
The SMT process begins with the application of a thin layer of solder paste to the circuit board, using stencils to ensure that it is applied in only the designated areas. The components are then placed on top of the paste, either manually for low-volume production or automatically for high-volume manufacturing. After the components are in place, the entire assembly is passed through a heated reflow oven where the tin in the solder paste melts and bonds to the leads of the components, forming an electrical and mechanical connection.
After the reflow oven, the assembled PCBs are inspected for defects such as missing or misaligned components and solder bridges. If a problem is found, it is usually repaired at a rework station by a human operator. The finished products are then sent to testing stations where they are examined in-circuit and functionally tested to ensure that the circuit boards work correctly.
The smaller lead spaces and close proximity of SMT components can make manual soldering more difficult, increasing the risk of mistakes such as solder bridges and other problems. SMT is also not well-suited for components that generate a lot of heat or have a high electrical load, as the small lead spaces can reduce the effectiveness of thermal management in the case of overheating. Candor has a solution for this with our innovative press fit copper coin technology that can help improve the heat dissipation of these types of components.