Guide To Surface Mount Technology

Surface Mount Technology (SMT) is the method used to paste and solder components directly to circuit boards using automated production lines. An electrical component mounted in this way is referred to as a surface-mount device (SMD).

The majority of available electronic components can be mounted on circuit boards using this technology and it allows components to be mounted on both sides of a circuit board without the need to drill holes through it.

Surface Mount Technology is used for products that range from USB flash drives and smartphones to medical devices and portable navigation systems.

As the most common PCB assembly process, it comes with a multitude of benefits. This guide will help you to understand the many benefits of choosing SMT as part of your PCB manufacturing.

Benefits of using SMT include:


Greater density of component mounting


Easy manufacture of ever-smaller, lighter and more powerful PCBs


Faster assembly rate than through hole insertion


Well suited to complex and unique PCB assembly requirements


Reduction of mechanical heat and noise


Greater reliability


Significant cost savings

Surface Mount Technology – Higher Component Density

The automation of the Surface Mount Technology process means a greater density of component mounting can be achieved – i.e. a large number of components and connections per component can be placed on small circuit boards. This allows for much greater efficiency within the manufacturing process of much smaller PCBs.

A much higher density of connections on the circuit boards is possible because there are no holes to block the routing space. As more components can be closer together on the circuit board, the PCB design can be much more lightweight and compact.

SMT electronics assembly allows for the manufacture of products with ever smaller dimensions. As such, very small and sensitive components, such as resistors and diodes, can be quickly and effectively mounted on circuit boards.

SMT is a perfect technique for complex and unique assembly requirements. In addition, it is also highly customisable and comes with the power and flexibility to meet these types of PCB assembly demands.

Surface Mount Technology guide

Cost Savings Through Surface Mount Technology

One of the greatest benefits of using Surface Mount Technology is the cost savings which can be made at all stages of the manufacturing process, when used as an alternative to Through Hole Assembly. These include:


Lower initial cost and set-up time for mass production


Faster automated assembly leads to reduced production time


Greater uniformity in component soldering means less room for error


Many SMT parts cost less than through hole parts


Reduced labour costs

The Surface Mount Technology Process

The SMT assembly process, which is used by the electronics experts at MPE, follows this method:


Solder paste is applied on the board through a solder paste printer, using a template (also known as a stencil or solder screen) to ensure it is accurately applied to those places where components will be mounted. An inspection will pick up any defects and the printing reworked or the solder paste washed off prior to second printing.


The PCB is then sent to the pick-and-place machine where components or ICs are mounted on to their corresponding pads via component reels in the machine.


Once all the components are in place the board goes through reflow soldering, passing through a furnace, causing the solder paste to liquefy and bind the SMD components to the board.

Our machines will check that the part used in the assembly process matches its specification and, when the PCB is populated, high speed Automatic Optical Inspection (AOI) machines can verify that the part fitted to the PCB is in the right place and matches not only the specification but is also soldered correctly.

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If you’re looking for a PCB supplier, ready and prepared to adapt to your specific or changing needs, please contact us at

As a team, we’re proud that we have been able to leap in and meet unit production quotas already. But what this really means is that we’ve proven to the client, ourselves, and prospective clients that they can continue to pursue ambitious growth plans when they partner with us.

Find out more about our electronics manufacturing and assembly services here.

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