Through-hole was once the king during the 1950s. It dominated the electronic industry as the top printed circuit board (PCB) assembly technique at that time. However, despite being the better mounting technique then, it still had some significant flaws that needed solutions.
30 years forward, another mounting technology rose to fame. Since its popularity surged in the 1980s, Surface Mount technology (SMT) took over the industry like wildfire. It has completely devoured its competitors, including the once revered through-hole, as the most preferred mounting technology in PCB assembly.
SMT is the process wherein the components are mounted directly onto the PCB. It involves applying solder paste through a stencil or screen to the areas of the board where it is required. The components are then set in place using a pick and place machine. Then, the board with the components is placed in a surface mount machine to solder them.
With the promises and solutions brought by SMT, the electronic industry benefited greatly from this discovery. These advantages that are not present in through-hole include the following.
One significant changes made in SMT is the size of its components. Surface mount components (SMC) are now comparably smaller than the old through-hole components. Because of the smaller size, several advantages sprung from this change.
First, SMC take lesser board space than through-hole. Since the components in SMT are now smaller, it does not require bigger space from the surface of the board. As a result, there is an increase in pin count of components in SMT.
With smaller components, smaller and lightweight circuit boards are produced. Smaller board means faster circuit speed, which is ideal for many applications.
Both Sides of the PCB Can Be Used
In SMT PCB assembly, the components can also be mounted on both sides of the board. Since this process does not involve drilling holes, placing components on both sides of the board is possible.
This makes the surface mount boards to have higher density per unit area compared to through-hole. There are also more connections per component in SMT, which maximizes the computing power of electronic devices.
Although the cost of the machine can be steep, other production costs can be reduced in this technology. This is because production materials in SMT are comparably cheaper than that of through-hole.
These reductions include setup and production costs. For instance, the lower the drilled holes in the board, the lower the price of the PCB. In addition, electronic components are also cheaper in SMT PCB assembly.
Since there are less mistakes committed in surface mount, damage costs is also reduced. Lastly, smaller boards are also less expensive than larger ones.
Since the process of placing components onto the board is simpler and is automated, SMT provides much faster productions than through-hole. Placement machines are capable of attaching over 136,000 components onto the board per hour.
The high volume production is suitable for companies to produce more without spending too much.
With SMT, assembly of components onto the board is secured from trailing components or loose leads. Since a machine is used to set the components in place, the room for errors is lesser compared to through-hole. Even if there are errors, it can be corrected easily because of the surface tension which pulls the components to align properly.
Since SMT produces smaller boards, this also provides better performing PCB. The lesser space consumed makes more components to be placed on the board. With more components, there are also more connections built which can greatly improve the functions of the board.
There are also fewer unwanted RF signal effects, which leads to high frequency performance. Furthermore, SMT provides a better mechanical performance. It can withstand certain conditions such as shaking and vibrating.
SMT is undeniably the better option when it comes to assembling a circuit board. It is the perfect technique for designing and production. The skills and technology in SMT is also incomparable to the other techniques.
With SMT, manufacturers enjoy the benefits it provides. Thus, it enables them to compete better in the market.
However, despite the clear benefits of SMT, through-hole still remains useful in the quick turn PCB assembly today. For instance, it is still the ideal technique used in the prototyping process. Hence, combining these two techniques is still necessary to come up with the optimum results.
Whether it is SMT or through-hole, we at Imagineering ensure that we have the right skills and knowledge to utilize these mounting techniques.