PCB fabrication has more than one way of mounting components into the board. While though-hole methods have been the most prevalent long ago, surface-mount technology (SMT) brings something new into the field. At this point, you may not be sure on how to go about finishing your design schematics. To help you decide, here is an outline of the advantages and disadvantages of SMT and when it is appropriate for use.
What is SMT?
Components in SMT are placed directly on top of the PCB to produce a surface-mount device (SMD). Because of the effectiveness of SMT, through-hole technology has been widely replaced for fabricating PCBs, but both methods can actually be used on the same PCB because there are some parts that are simply not appropriate for surface-mounting. These parts may include heat sinks, high-power semiconductors, and huge transformers. In general, SMT parts for PCB fabrication are smaller than through-hole parts because they use smaller leads or do not actually use leads at all.
Advantages of SMT
Certainly, the main advantage of SMT is size. Since today’s electronic devices are usually more compact, there is a growth in demand for smaller PCBs. Surface-mount technology makes this possible. However, in spite of the fact that these PCBs are not as large as older units, there really is a far greater component density and there are more connections for every component. This translates into having more advanced and efficient electronics. SMT requires fewer holes to be drilled into the PCBs, which allows for a more automated and quicker PCB fabrication process. Moreover, the fact that the parts can be placed on both sides of the PCB simplifies things even further. Apart from all these, there are lots of SMT components and parts that are really less expensive than their through-hole counterparts. Because of this, you would need lower initial costs and require less time for setup and production. You will also enjoy decreased manufacturing expenses, and you could use your time more efficiently.
Disadvantages of SMT
Unfortunately, there is no perfect PCB fabrication process, and SMT also has its disadvantages. For instance, SMT is not suitable for any bulky, high-voltage/high-power component. For this reason, through-hole technology and SMT might need to be used together to achieve better results. Moreover, the small size of SMDs could create problems since the solder joint dimensions continue to become smaller as developments emerge. This ultimately means that less solder can be used for every joint, which could lead to voiding and integrity concerns. The solder attachments of SMD are prone to being damaged through plotting compounds when they run through thermal cycling. Finally, SMT must not be used as the only attachment method for any part that might be susceptible to current mechanical stress. An example of this is a connector that is used to interface with an external device, which is often attached or detached.
Using Surface-Mount Technology
Because of the many advantages of SMT, most modern products are made using it. In spite of this, SMT is not suited for all cases. You can consider SMT if:
•The product is very small.
•The product should accommodate huge memory volumes.
•The finished product has to be light and sleek regardless of component density.
•The product has to operate at high frequencies/speeds
•You have to manufacture large volumes using automated technology.
•The product must transmit little to no noise.
After much consideration of which PCB fabrication process to use, you can consult with a reputable PCB manufacturer to confirm. Well, if you’re still unsure, don’t forget that you could ask your preferred fabrication company if SMT is the right method for your product.