As PCBs continue to grow in complexity, PCB assembly has become an even more critical aspect of electronics manufacturing. Even a small assembly error could lead to poor performance or failure of an electronic device in the field. Given the criticality of this step, it is important that OEMs partner with a knowledgeable company, like RiverSide Integrated Solutions (RIS), for PCBA. RIS has the requisite experience and proven processes to guide OEMs through the PCBA process and select the right assembly technologies to ensure success in the field.

One of the PCB assembly methods commonly utilized is Surface Mount Technology (SMT). SMT makes it possible to manufacture more reliable assemblies at a reduced weight, volume, and cost, and is an excellent choice for most electronics assembly. SMT is a particularly good option for electronics that need to accommodate a high density of components or require a smaller, lighter board. Also, SMT is often highly automated making it a good choice for high volume production. Before diving deeper into SMT, it will be helpful to better understand where SMT fits in the general PCBA process.

Main Steps in the PCBA Process

Below are the primary steps in the PCB assembly process. The steps and sequencing may vary slightly depending on whether SMT or THT technologies – or a combination of both – are employed; however, the following describes the key elements of any PCBA process.

1. Apply Solder Paste: the first step in PCBA is to apply the solder paste to the sections of the PCB where components will be surface mounted. The paste is a mixture of solder and flux that is used to permanently join the components to the board in future steps.

2. Place the Components: the next phase is to place the necessary components on top of the solder paste. This step is often called “pick and place”. Depending on the functionality of the PCB, the components being added to the PCB may be resistors, capacitors, inductors, sensors, or other electrical parts.

3. Soldering: the purpose of this step is to permanently bond the components to the PCB. PCBA processes using SMT typically utilize a reflow oven and conveyor system during the soldering step to melt the existing solder paste. With THT, the component leads are inserted through the existing holes and a wave soldering method is often used where a wave of molten solder flows across the bottom of the board. In both cases, the molten solder joins the components and leads to the board. The assembly is then cooled to solidify the solder once again and fix the components in place.

4. Inspect the Assembly: this phase of the PCBA assembly process is crucial. Proper inspection is necessary to ensure the prior steps were performed effectively. This step may entail both manual and automatic inspections.

5. Testing: the final step in the PCB assembly process is testing to ensure the PCB functions as designed. There are various test methods such as flying probe, in-circuit testing, and others. Once testing is completed, the PCBA process is complete.

What Exactly is Surface Mount Technology?

As noted, SMT is a widely utilized soldering method for PCBA. As the name implies, SMT attaches components directly to the surface of the PCB using tiny amounts of solder paste and does not require any holes in the board. In a SMT PCBA, the solder joint forms the physical and mechanical connections. Electronics made via SMT are called surface mount devices, or SMDs. Surface mount technology allows components to be mounted to both sides of the board, allowing for more components on a given board and smaller PCBs compared to PCB assembly using THT only. SMT often involves automated equipment that position and mount the components on the board. For more details about SMT at RIS, watch our short video

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Advantages of SMT

There are many advantages to using SMT during PCB assembly. Below are some of the key benefits.

Increased Component Density: the geometric size and volume of SMT components are typically less than THT components. For this reason, SMT is able to fit a larger number of components on a PCB surface. This enables designers to create boards with high component density. As electronics become tinier and the demand for more functionality increases, higher density PCBs is becoming an even bigger advantage of SMT.

Increased Efficiency and Throughput: elements of SMT are often automated, which enables rapid and precise mounting of the components on the board. This leads to efficiency gains that enable higher volumes of production while maintaining excellent reliability. Higher throughput of PCBs also results in lower cost per board – another big advantage of SMT.

Smaller, Lighter Weight PCBs: SMT is able to utilize smaller and lighter components compared to THT. This enables SMT to create compact PCBs that maximize the space on the board without sacrificing functionality and performance. Lighter weight PCBs is an important advantage of SMT for industries where weight is critical such as aviation.

Simpler PCBA: THT assembly method requires component leads be bent into shape and inserted into holes drilled in the PCB solder joints. Conversely, SMT mounts components to the board without much, if any, drilling resulting in a much simpler and faster PCB assembly process. Additionally, SMT does not require lead forming since component leads, if any, are surface mounted to the pads. For these reasons, SMT makes PCBA much faster and less prone to error than THT.

Superb Reliability: surface mounted components are often more reliable than through-hole components. In particular, SMT components are less prone to failure due to conditions such as vibration, shaking, and shock.

Mixed Technology Boards: SMT and THT components are able to co-exist on a single board. This enables designers to create electronics that employ both THT and SMT methods during PCB assembly. This may be necessary for designs where space constraints require using both types of connectors.

RIS PCB Assembly

At RIS, PCB assembly is one of our core competencies. We provide reliable, seamlessly-assembled printed circuit board systems built with extreme precision. Our skilled engineers, technicians, and assemblers work to expertly put together a complete PCBA. When you choose RIS for your PCBA projects, you can expect the hands-on customer care of a small manufacturing operation and the capabilities characteristic of a much larger company with our complete electronics manufacturing services for OEMs in any industry. Our PCB assembly expertise includes various technologies and methods including SMT.

About RIS

RIS is an advanced contract manufacturer providing robust solutions in circuit board assembly, product assembly, kitting, supply chain management, fulfillment, distribution, and reverse logistics. We employ more than 300 people and provide services to OEM’s across the world. We operate 3 state-of-the-art manufacturing facilities within the U.S, and as your one-stop-shop we have the capabilities, capacity, quality assurance standards, and resources to provide you with support for all of your manufacturing needs.

With all of the choices in contract manufacturers out there, we know it can be difficult to find someone that not only understands your business model but also has your best intentions in mind. RIS has proven to always be a win-win focused relationship. As your one-stop-shop, we have the capabilities, capacity, quality assurance standards, and resources to provide you with support for all of your manufacturing needs. We understand that supply chain management is difficult and very time consuming, so we urge our customers to utilize us in the fullest capacity. Our total-package solutions include:

· Extensive supply-chain network

· Purchasing and inventory management

· Dedicated Program Manager

· Warehousing and drop-shipping capabilities

· Flexible order fulfillment

· Product assembly: sub-assembly and full product

· Scalability to meet your needs

Contact us today at (507) 523-3220 to see how we can help with your manufacturing project, or click here for a quote.