PCBA or PCB assembly is undoubtedly the key process in the life of electronic devices. Printed Circuit Boards are just a blank piece of fiberglass and copper routing before they are assembled. With its electronic components attached, manufacturers can use this board to create the brains for the range of electronic products that people use every day, from digital clocks to sophisticated aerospace applications.
It is crucial for anyone in the electronics manufacturing, design, or procurement process to understand how these components are connected. The type of assembly used can affect the price, manufacturing time, strength and size of the product. This can result in unscheduled hardware failures, production delays or wasted manufacturing costs.
Most of the time, engineers and manufacturers have specific methods they use for assembly, depending on the requirements of the project. Both have their own unique merits in terms of the types of components, the operating environment, and the number of components to be produced. Continue reading to discover the most popular methods of PCB assembly in the industry today and how they influence electronics.
The Top PCB Assembly Methods – Exploring Them
There are three primary methods used for printed circuit board assembly, which are primarily used in the electronics industry. Each one of them is used by manufacturers depending upon the device being created.
Surface Mounted Technology (SMT)
In today’s electronic manufacturing industry, the most common technology for making printed circuit boards is called surface mount technology (SMT). Unlike the traditional component insertion process, SMT is a process in which the components are soldered to the surface of the PCB. This method is very automated, and is extremely efficient for mass production.
Typically, the SMT process has several stages. First, a solder paste printer uses a solder paste stencil to precisely print the correct quantity of solder paste onto the board. Then, through a rapid pick and place process, a robot machine places the small electronic parts on the spots where they are to be pasted. The board is then passed through a reflow oven where the solder paste is heated up and makes a strong, permanent electrical connection. Last but not least, the board is subjected to automated optical inspection (AOI) to identify misaligned parts or soldering errors.
SMT is a great advantage in several ways. This enables components to be mounted on both sides of the board, resulting in greater component density and smaller overall board sizes. The reason behind the compactness of smartphones and wearable devices. In addition, the high degree of automation eliminates a significant amount of labor and increases production times.
Through-Hole Technology (THT)
Through-Hole Technology (THT) is an older assembly technique, but it is still quite relevant in particular applications. In this process the components are given long metal leads which are drilled into the printed circuit board. The leads are then soldered to the other side of the board.
The assembly of THT can be carried out manually or by means of automation that can be achieved with a wave soldering machine. Wave soldering is a process in which the board is fed through a pan of solder and the solder washes over the bottom of the board and gives a good bond between the bottoms of the component leads and the holes.
The main advantage of THT is that it provides mechanical strength. The physical bond is very strong since the leads pass through the board and are soldered to it. For this reason, THT is the perfect solution for heavy components, large connectors, and applications that will experience heavy mechanical stress, vibration, and extreme temperatures. THT is commonly used in industrial machinery, automotive systems, and military applications, where reliability is paramount. This technique, however, demands more space in the board and it is generally slower than SMT for making a product.
Mixed Technology Assembly
A lot of the latest electronic gadgets require both the advantages of SMT and THT on the very same board. Within the mixed technology assembly, engineers can take advantage of the mechanical strength of through-hole technology with the compact size of surface mount technology.
Normally, in a mixed technology process, the manufacturer would first install the SMT components. The board passes through the solder paste, pick and place and reflow oven. After the delicate surface mount parts are in place, the through-hole components are placed in. The board is then subjected to the wave soldering machine or manually soldered depending on the layout and heat sensitivity of the previous SMT components.
In power supplies, telecommunication devices and consumer electronics, where a combination of high-density microchips and high-power connectors are required, mixed technology is often employed. It makes it a little more complex to manufacture, but it offers the most design flexibility.
Mastering the correct method of assembly
Choosing the right assembly process involves careful consideration of the product design and use. In consumer electronics, where lightweight, slim design and fast, high volume production are key features, SMT is almost always the first choice. When the primary considerations are cost efficiency and miniaturization, SMT is the obvious choice.
However, if you are creating a product that requires ruggedness, you would need THT to do the job. Through-hole mounting provides the structural integrity that is needed with high power circuits, large capacitors, and external ports that are frequently plugged and unplugged.
Most complex industrial or commercial applications will require a mixed-technology application. With a knowledgeable and experienced PCB assembly company, you can decide on the best combination of SMT and THT so that the final product is both cost-effective and reliable.
Conclusion
One of the most crucial factors to the success of your electronic device is the PCB assembly process you choose to use. By understanding the differences between Surface Mount Technology, Through-Hole Technology, and mixed assembly, you can make informed decisions that align with your budget, production timeline, and quality requirements. Check your components list, evaluate the physical stresses that your product will undergo, and check in with a trusted manufacturing partner like Optima Technology to successfully manufacture the PCB board to come to fruition.
