Skip to content

An Overview of Surface Mount Technology

Technological advances have become synonymous with electronics. As a result, the riding significance of circuit boards in this dispensation has not only shot to prominence but become an aspect every electronics student, engineer, designer, and enthusiast must know. This article details a key aspect of printed circuit boards in SMT technology to help you understand every useful aspect of this tech concerning printed circuit boards.

Surface Mount Technology (SMT)

SMT is a component assembly tech related to PCBs where components get connected and attached to the board’s surface by a batch solder-reflow process. The SMT process leads to an SMT PCB, an excellent substitute for older through-hole PCB manufacturing and design practices. It has predominated instances where weight, size, and automation become key considerations s it can fabricate printed circuit boards efficiently and without any loss of quality and reliability.  

The technology has expedited the deployment of electronics for diverse applications previously regraded impractical. SMT utilizes SMDs (surface mount devices) through SMD technology to replace heavier, larger, more unwieldy equivalents in the through-hole PCB construction.

The Benefits of Surface Mount Technology

  • Automated assembly: It proves easy to install most SMT components on circuit boards through the automated pick and place equipment. Here, high volume components like passive components get loaded from reels into this automated machine while other components from trays or tube feeders. It represents a crucial difference from PTH components that often need manual assembly.
  • Components commonality over PTH.  Surface mount technology parts often cost less compared to the PTH equivalents due to their volume and size. SMT components also prove in demand and thus always available compared to through-hole parts.
  • Size. Surface mount technology parts come way smaller compared to their PTH equivalents as they lack long leads for insertion and soldering into the holes. Consequently, it allows you, as the designer, to incorporate more parts within the same limited board space.
  • Electrical performance. The SMT PCB has stronger signal integrity than PTH PCB, as its small size, besides fitting more components, leads to shorter signal routes on the PCB. It will also generate less heat compared to PTH.

Almost every piece of equipment manufactured commercially in the current dispensation uses SMT for its diverse benefits during manufacturing. Therefore, more printed circuit board devices become available as packages or SMDs, which qualifies the tech adoption as cost-effective and practical.

SMT Manufacturing

Surface mount technology machine

Construction of boards using the surface mount technology leads to an efficient automated printing circuit board construction process, especially in mass production. Manufacturing benefits derived from SMT include enhanced performance and reliability, maximum flexibility, reduced physical intervention when it comes to component placement, and increased automation. Additionally, it leads to lighter and smaller boards, near-total eradication of operations that involve drilling holes, easy assembly, increased density, and complementarity with THC in one board.  

SMT Manufacturing Processes

SMT manufacturing becomes pivotal in the production of Surface mount technology PCBs. The fabrication process often consists of numerous high-automated processes. Such steps involve the following.

  • ​The PCB board material has solder pads lacking holes, and thus, the solder paste has to get applied using a screen-printing-like procedure. Here, the placement gets controlled through an exact stencil template (specific to the PCB getting fabricated) to ensure the material gets applied solely to the required regions.
  • Computerized machines become essential for the component selection and placement; after that, position the preferred SMDs and further components appropriately on the PCB board. Finally, the components (including SMDs) get fed into the machine on tapes or reels. However, for specific components like the integrated circuits, the delivery gets carried out through static-free media.
  • The boards then undergo soldering, where the heating of the soldering pads continues until the applied solder paste melts and subsequently bonds with the board’s components. In specific scenarios where either side of the PCB has to get used for components, the soldering/placement processes are repeated on the alternate side.
  • Any component that proves heat-sensitive can then be integrated into the printed circuit board after the automatic soldering process is completed. Please note that this process can happen manually or via processes that cannot mutilate the component.
  • After this, the boards get “washed” to eliminate excess solder residue or flux, resulting in component short-circuiting because of their placement tolerance.
  • Once completed, cleaned, and dried, the printed circuit board can get inspected for the last time to ensure the correct quality. The inspection process often looks for missing components, soldering issues, and alignment issues that can generate problems. The good news entails the ability to access the automated and inspection equipment.
  • Inspected boards after that proceed to the next level, where the circuit gets tested for functionality.

The Value of Going through a Third-Party Printed Circuit Board Manufacturer

The creation of a decidedly mechanized process when it comes to SMT construction sanctions grander benefits in fabrication. However, the equipment required for SMT manufacturing can prove prohibitive regarding cost, not only to you as a designer but also to other companies. Therefore, it becomes wise to rely on RayMing PCB and Assembly Company for your SMT manufacturing and fabrication needs. You will not only benefit from our dedicated resources but experience first-hand the efficiency and quality of our SMT manufacturing.

RayMing PCB and Assembly Company prove a leading PCB manufacturer not only in China but across the globe. You can always rely on us for incredible customer service and reliability when delivering specified designs. In addition, the company can assist you in incorporating top-rate SMT into your printed circuit board fabrication process.

Factors to Consider When Picking the Best Technology for Your Design

It always becomes instrumental in deciding on the technology to deploy early. In fact, you should determine whether you will use the SMT or PTH at the component selection stage during schematic design.  If you incorporate these components early when designing, you will ensure that your PCB Layout is developed using the right component package tracks/footprints. However, to choose the best tech for your design, consider these points in your decision-making.

  • Use. What will be the specific component exposure to touch and other stresses? For example, will it get “touched” frequently or get subjected to extra stress?
  • Power. You have to consider the amount of heat and power the component will conduct during usage.
  • Performance. What type of package style has the promise of giving your circuit top performance?
  • Price. Try and deduce whether picking a specific package style over another will reduce the cost?
  • Availability. Gauge and go with the package that can readily get accessed in creating your prototype
  • Rework. Do you anticipate plenty of circuit rework during the prototyping stage?
  • Assembly. Try and deduce what package style can provide you a top-rate quality assembly and at a minimum cost.

An SMT part can prove the ultimate go-to component for your design needs. First, however, it becomes crucial to stop becoming afraid of the through-hole parts, especially if necessary. At this point, your PCB manufacturer can come in handy in helping you select the best way to go. The manufacturer not only has the benefit of understanding printed circuit boards but boasts the benefit of hindsight, having worked with almost every component package style concerning printed circuit boards. Therefore, you can benefit from their recommendation.

At RayMing PCB and Assembly, we boast an operational experience of over fifteen years of building and fabricating PCBs. The company has a strong and skilled team of engineers dealing with components to guide you accordingly, especially regarding parts availability and their corresponding prices. Meanwhile, another set of our engineers dedicated to the PCB manufacturing process will skillfully develop your board with quality based on your design specifications.

The Process of Surface Mount Assembly

The assembly process of surface mount technology encompasses several crucial steps, and notably from the design phase. Here, you need to pick all the relevant components before designing the SMT using Cadstar or Orcad. Remember, other software design tools exist just in case you cannot access these two. Try and incorporate as many design features that will prove relevant to the functionality of your PCB.

Once you have finalized the design and picked the components, the printed circuit board data must get sent to the manufacturing company. It also becomes crucial at this stage to buy components using the automation guidelines. Consider the PCB design and develop specifications that include surface finish before encoding all these in the relevant Gerber file format and sending.

Upon payment, you will get your package components, especially in reels. Therefore, it becomes crucial to avoid components that come loose in their packaging. It becomes crucial as it can demand that you buy specific feeding plates or place them by hand, something that can prove inconvenient.    

After receiving the components complete with your PCB panel, you must set up the necessary machines pivotal in the production/manufacturing process. For AOI and placement machines, create the relevant operational program from Gerber.

Print the solder paste using the solder paste machine printer, the solder paste, and the printing stencil. Ensure that everything runs smoothly in this phase to avoid errors that might cause catastrophe later on.

Inspect the solder paste, and once ascertained, carry out the component placement, AOI, and FAI. You then conclude the assembly process by verifying the process via x-ray inspection.

Conclusion

Surface mount technology has plenty of benefits that should always sway your decision into preferring them for your PCB design needs. However, moments arise where through-hole technology becomes pivotal; therefore, never lose sight of this.