PCB Tech - Where does the technical advantage of smt show?

PCB surfacemount technology

Surface mount technology (SMT) increases the benefits of manufacturing circuit boards and reduces weight for many reasons:

The components are placed directly on the surface of the circuit board, rather than connected via holes on the circuit board (through-hole technology). Many of the SMT components, commonly referred to as surface mount devices or SMDs, are smaller and lighter than their counterparts, partly because the leads required for through-hole manufacturing are reduced or eliminated. Through the standardization of components and design tools, manufacturing can be automated to a large extent.

SMT originated in the 1960s, when IBM used this method to design small computers, which were then used in the guidance system of the Saturn rocket space program. Since then, the concept has been continuously refined and improved.

SMT advantage

SMT allows engineers to design circuit boards with components on both sides of the circuit board material. By eliminating or reducing the need for drilling and component holes, there is no restriction on the placement of circuit components on the opposite side.

Design flexibility is another advantage of the SMT structure. There is no conflict between combining SMT and through-hole manufacturing methods on the same circuit board. This allows PCB designers to freely create dedicated circuits without the need for multiple circuit boards, just provide the required functions.

Other unique advantages of SMT printed circuit boards:

Size-The reduced component size is equivalent to containing more components on a single circuit board, and subsequent products require fewer circuit boards. With today's demand for miniaturized products and weight reduction, these attributes are critical.

Double-sided installation-no need to design drilling and connecting plates, components can be placed on both surfaces of the PCB.

Quality-The manufacturing process for placing components and performing soldering functions can actually improve placement reliability. The surface tension of the soldering function actually corrects slight alignment problems and improves placement tolerances.

Reliability-SMT connections are not susceptible to failure or shaking due to vibration.

Manufacturing Speed-Especially when designing a circuit and insisting on Design for Manufacturing (DFM), SMT improves production efficiency and reduces set-up time by eliminating or reducing drilling operations.

Reduce cost-Many smaller size surface mount devices (SMD) or components actually have a lower cost than the larger through-hole version.

SMT-Disadvantages-Disadvantages

SMT technology is not without its shortcomings:

Connection-SMT does not work under mechanical stress conditions, such as where physical connections will frequently attach and detach.

Joint size-due to the nature of SMT, the solder connection is smaller, facilitating smaller components. This results in a smaller amount of solder used in each contact, which may affect the reliability of some solder joints.

High-power applications-where large components are required in the circuit such as fuses, large capacitors or large connectors, SMT is not the best solution for PCB manufacturing. In this case, the actual approach is usually to combine the use of SMT with through-hole design for larger components that require heat sink considerations, such as transformers or semiconductors. In fact, such larger devices are sometimes combined on the same circuit board, but are manufactured using through holes.

Prototyping-This is unlikely to be an effective application of SMT. If you need to add or replace components, you may need specialized tools and skills, especially when the circuit board is composed of high-density component placement.

SMT is in use

The SMT structure is regarded as the main design and manufacturing standard of today's electronic equipment. A closer look at almost all consumer products, cars or computers, you will find that SMT boards are used in large quantities. With its reliability, light weight, size reduction and manufacturing cost advantages, SMT boards can be used in any situation that requires reliable, high-volume PCB manufacturing.

Design for Manufacturing (DFM) software tools provide circuit designers with SMT component placement guidelines, which can improve manufacturing efficiency and reduce the possibility of designs that cannot actually be manufactured. This saves time and money by reducing the need to rework and redesign complex circuits.

Most SMD industry standards further simplify the design and manufacturing considerations to coordinate work and produce stable quality PCBs effectively using automated manufacturing processes and equipment.