Surface Mount Technology (SMT)

Surface Mount PCB Assembly

SMT is a flexible and powerful assembly process that has allowed manufacturers to produce modern devices with ever-smaller footprints. In SMT, all the different components needed for today’s devices are attached to the surface of the printed circuit board. SMT can be highly automated, so it’s a natural fit for clients who need circuit boards in high volume, but it’s also highly customizable. If you need circuit boards assembled to meet unique requirements, SMT may be the best choice.

EMSG is a longstanding provider of surface mount PCB assembly services for customers in a range of industries. We specialize in contract manufacturing and have extensive experience with assembling electronics for a wide range of applications. With a broad selection of equipment and expert staff, we can assist with product prototyping and testing, contract manufacturing and more. Read on for details or contact our office directly to request a quote.

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How Does SMT Work?

Briefly put, SMT is a process for electronics assembly in which electronic components supplied are mounted to the surface of a printed circuit board (PCB). It’s a highly automated and flexible process that allows manufacturers to construct circuit boards with a wide variety of components.

Surface Mount Technology (SMT)Surface mounting has several advantages over similar PCB manufacturing techniques. Perhaps most importantly, it allows for much smaller products — up to one-third the size and one-tenth the weight of through-hole boards — and higher connection densities. SMT enables manufacturers to place increasingly complex circuits into small assemblies, so it has been a crucial factor in the proliferation of small electronic devices in everyday life.

Surface mount boards are also faster and easier to assemble and more cost-effective than boards constructed with through-hole technology. Through-hole PCB assembly is an older technology which involves attaching leads to holes drilled into the circuit board. This process creates very durable products, as these connections are quite sturdy. It can be more expensive than SMT, though, and the component density is generally higher. Our engineers can help you determine which assembly process best fits your use case.

There are four basic steps in the process of PCB SMT board design assembly:

  1. Prepare the printed circuit board
  2. Place the components
  3. Reflow soldering
  4. Inspection

1. Preparing the PCB and Initial Circuit Board Design

Before adding components to the circuit board, the assembler uses a solder paste printer to place solder paste where it’s needed on each circuit board. The solder paste is a mixture of solder particles and a special flux. Heating this solder paste during the reflow process causes the electrical connections to form.

Manufacturers often use a stencil and squeegees to make sure that the solder paste is printed in the right places on each circuit board. Jet printing is another option for prototype PCB assembly.

Surface Mount Technology (SMT)

2. Placing Surface Mounted Components Components

After the solder paste is applied and inspected, the assembler carefully places the components on the circuit board. Typically, these components are packaged in trays, reels or tubes so that a pick-and-place machine can use a vacuum or gripper nozzle to pick the components and position them on the flexible PCB.

There are a variety of components and connection types used in SMT. Transistors and diodes are typically housed in small plastic packages while integrated circuits come in various kinds of packages. Simple chips might have as few as 14 pins, while more complex chips may need 200 or more. VLSI chips, for example, are rectangular packages with pins on all four sides. Ball grid array (BGA) packages are also quite common. Instead of establishing connections on the sides, BGA packages have connections underneath for a layered PCB design.

3. Reflow Soldering Process

The solder paste holds the components in place temporarily, but the electrical components are not fully attached to the unit and the electrical connections are not formed until the PCB layout undergoes reflow soldering. In a reflow oven, the units are heated until the solder paste reaches a temperature high enough for the solder joints to form. This process needs to be controlled carefully as the maximum temperature of the components may be close to the temperature required to create acceptable solder joints.

Surface Mount Technology (SMT)

4. Inspection

Quality assurance inspection can take place at a couple of key moments in the SMT process, depending on the equipment used and the design requirements. Before components are attached, the solder paste is typically inspected to ensure there are no printing defects. Inspection is also common before and after reflow soldering.

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Advantages of SMT

There are many advantages to using surface mount technology, including the following:

Surface Mount Technology (SMT)

 A chief advantage of SMT is that it can attach very small components and do so at high densities. For this reason, SMT leads to overall smaller units than can be constructed with other manufacturing processes. With the use of contact terminals instead of leads, SMT components can be miniaturized to the size of one grain of sand.

In the through-hole process, components can only be placed on one side of the board — the pins sticking through place a hard limit there. With SMT, though, components can be attached to one side and then the other, allowing for more complex circuitry without significantly increasing the size of the overall unit.

Through-hole technology requires the drilling of holes in the PCB. While this does create secure connections, drilling adds costs to the manufacturing process. As SMT does not require drilling, it is often the more cost-efficient manufacturing process.

There are many manufacturing benefits to SMT that make it a highly automated process. Machines can conduct solder paste printing, component placement, inspection scanning and reflow soldering.

With SMT, you can attach a wide variety of components to circuit boards. Companies in a broad array of industries have deployed this assembly process because it enables them to customize boards for almost any application.

Our Equipment and PCB Fabrication Capabilities

High-quality products are made with high-quality equipment. EMSG is manufacturing PCB assemblies to the IPC-A-610 standard, in both leaded and ROHS technologies. This means that our products meet the international standard for reliability and quality in printed wiring assemblies.

We offer unique manufacturing capabilities because we have invested heavily in the advanced equipment necessary to turn around complex jobs quickly and to a high standard of quality. Our equipment includes:

  • Various printers for screen printing, including an MPM Accuflex
  • Three Samsung SM421 machines
  • A Decan F2
  • A Samsung SM482
  • Two machines able to populate a 4-foot continuous board

To ensure the highest quality products, we employ an array of inspection equipment. Two Mirtec MV-3L automatic optical inspection (AOI) units detect component defects, confirming that all components are attached, functional and have the right polarity. We keep a complement of equipment on-hand for functional and optical inspection and use a Cyberoptics Laser Section microscope to confirm that solder paste is applied to the correct height.

With an in-house x-ray inspection station, EMSG can conduct efficient inspections of BGA and Micro-BGA components. 

A Full-Service Manufacturer

In addition to being a surface mount PCB assembly company, we provide our clients with full-service manufacturing from assembly capabilities to box build to testing and inspection.

We’ll design, source and install the wiring harnesses, cables and sub-assembly components necessary for your device, and then put it all together in a custom-designed enclosure. Need the design software loaded and the system configured for use? We can take care of that and handle the packaging and labeling as well.

EMSG also performs the comprehensive testing and inspection services necessary to make sure that your products are functional and reliable. It starts with visual inspection under 100% magnification but can include automated optical inspection, in-circuit testing and functional testing.

View our conformal coating machine in action! 

Surface Mount Technology (SMT)

Importance of Quality Control

As a specialist in contract manufacturing, EMSG understands that quality is paramount. Our clients look to us to provide highly-customized units that meet the highest standards for quality and reliability.

EMSG performs all SMT PCB assembly services in our York, PA, headquarters. Featuring over 20,000 square feet of production space, our facility is designed to ensure a high degree of quality control on any job. Our ISO 9001-registered quality management system is based on industry-recognized best practices and employs a series of scalable, monitored processes to encourage accountability and transparency in everything we do.

Contact our office directly to learn more about our capabilities and certifications.

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Surface Mount Technology (SMT)

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Industries We Serve

With every client we work with, we customize our approach as necessary to deliver the best results for their needs. Because we specialize in contract manufacturing, making adjustments or modifying our workflow is easy. Our management team is available to consult on engineering and manufacturing issues, drawing from more than twenty years of experience to help you achieve results that respect your budget, timeline and technical considerations.

Which industries partner with us for electronics assembly? We are an ideal partner to the medical device manufacturing industry, where small surface mount boards play a critical role in the proper operation of various products. Other clients come to us from sectors such as telecom and communicationsindustrial and commercial equipment, traffic and transportation, lightingmarine equipmentenergy and utilities and other segments of the manufacturing market.

We’re ready to assemble medical devices that meet the strict sanitary and quality control requirements of the medical industry. 

Printed circuit boards are used across the energy and utility industries for a variety of use cases including wind turbines, utility control systems, solar arrays, pumps and robotics. Our SMT process provides the lightweight, customizable units needed in this industry.

Maritime navigation, engine management, communication, power and autopilot systems all rely on reliable PCBs. We custom-manufacture units for all manner of uses in the maritime industry.

Light-emitting diodes (LEDs) are an increasingly popular choice for lighting in a wide range of locations including homes and businesses. They have a long lifespan, they’re cheap to operate, and they’re environmentally friendly. They also require precision-designed circuit boards. From the board to the enclosure, EMSG can custom-design an LED lighting system for your application.

From consumer devices to network infrastructure, printed circuit boards are used across the telecom industry. Cell phones, telecom towers and processors, modems, routers, multiplexers and base transceiver stations all require reliable — and often quite small — circuit boards to handle their unique functions. The telecom industry has been one of our main areas of service since our founding in 1995, so we have extensive experience with assembling the units needed in this sector.

Manufacturers of all kinds often turn to contractors to produce the circuit boards needed for their products. Our circuit boards have found their way into everything from vehicles to HVAC control systems to consumer electronics. Whether you need a partner for prototyping or volume manufacturing, our engineers can meet your needs.

Modern vehicles rely on printed circuit boards for a variety of functions. Once strictly mechanical devices, vehicles now often come equipped with navigation systems, cellular communication abilities and sensor controls. Our PCBs are engineered to meet the high standards of the automotive industry. We work with our partners in this industry to design, prototype and assembly the reliable circuit boards that they need.


Surface Mount Technology (SMT)

Serving York, PA and the Surrounding Regions

Surface Mount Technology (SMT)No matter what industry or application you need circuit boards for, EMSG has the equipment, expertise and certifications to produce the reliable, high-quality products you need. Our location in York, PA places us near major East Coast population centers. We offer consultation by phone, email and in-person.

When you meet with one of our team members, we’ll take the time to get to know your requirements and the specifics of your industry. Surface mount PCB assembly is only one aspect of the process. We can provide a complete turnkey service that brings your product to market quickly and affordably while minimizing the risk of defects. 

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Quick Request a Quote Form

Ready to get started? Get in touch today to learn more about our surface mount circuit board assembly services and book a consultation at your convenience by filling out our request a quote form. If you don’t have design or Gerber files we’ll work with you to create a design. If you require a quick turnaround PCB quote or lead time, please let us know and we’ll work with you to accommodate your specific needs.

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