PCB Assembly Automation Helps Streamline the PCBA Production Process

As electronic products become more complex and high-performance, PCB assembly technology is also evolving and developing. Among them, intelligence and automation, as key trends, are increasingly affecting PCBA production. Advances in automation have provided us with high-density, high-speed, complex multi-layer circuit boards that run our computers, and operate our vehicles, ships, airplanes, and satellites. They help us communicate around the world, educate and entertain us through smartphones, and more. In order to streamline production in line with the demands of today’s technology, PCB assemblers are adopting newer and better ways to improve their manufacturing techniques. This article discusses some basics of PCB assembly automation to streamline production.

1. Benefits of PCB Assembly Automation

To meet the demands of evolving technology, electronic products continue to shrink in size. This is best evidenced by IoT devices, for which demand is growing at an alarming rate. While PCB manufacturing is growing to meet these demands, so are the expanding industrial systems that assemble and test circuit boards.

One way PCB assemblers are meeting these growing demands is by updating their manufacturing processes. For example, PCB assembly has come a long way from its early manual operations. Compact and miniature PCBs are mass-produced using the latest automated assembly processes, which brings countless benefits, such as:

Reduce Costs

Automation reduces manual assembly time and labor, which reduces assembly time and labor costs.

Faster Assembly

Automated assembly can be achieved at a much faster rate than manual assembly.

Reduce Errors

Automation eliminates human error in the manual assembly process. The randomness of human error is difficult to identify and eliminate.

Improve Quality

Automated assembly machines are designed so that delicate tasks can be repeated with a consistent level of quality that is not possible with manual labor.

Compact Size

Electronic components are now so small that it is no longer possible to assemble them manually. Automated assembly machines are the best way to handle them.

2. Purpose of PCB Assembly Automation

The best way to learn about PCB assembly automation is to visit a contract manufacturer that makes PCBs. The level of automation that exists is astounding. For example, automation can sort and spread components, place components on boards, apply encapsulant, and test boards, and package the final product.

To speed up assembly, PCB manufacturers and assemblers are making maximum use of automation. For example, PCB assemblers use automation to:

√ Component identification, marking, and labeling

√ Dispensing solder paste at specific locations on the board

√ Picking and placing components on the board

√ Soldering placed components, usually using a reflow oven or wave soldering system

√ Separating individual boards from the panel by routing

In addition to the above, there are also automated test processes such as:

• Visual inspection of boards using optical and X-ray systems

• ICT or in-circuit test systems to verify individual network connections and the manufacturing integrity of the PCB

• Flying probe test systems to verify the electrical characteristics of the board

• Functional test systems to verify the functionality of the assembled board

In addition to the above automation systems that are directly essential to PCB assembly, there are many other systems that facilitate the smooth operation of the entire assembly line. These are essential for the logistics, tracking, and general transportation of goods:

√ Conveyor belts for transporting materials and sheets.

√ Barcode readers for handling and tracking boards and components.

√ Component delivery systems for delivering components to placement machines

√ Packaging systems for sealing and dispensing the final PCB products.

All of the above automation is necessary for the smooth and efficient operation of the entire PCB manufacturing and assembly plant.

3. PCB Assembly Automation Workflows

As technology advances, most electronic components have become increasingly complex, making it difficult to handle them manually. This creates a need for automated systems to handle them during the PCB assembly process. In addition to making the assembly process more efficient, these automated systems also enable higher production yields, increased reliability, better quality control, and easier handling of complex circuit boards. Automation is necessary at every stage of PCB assembly:

1) Component Identification, Marking and Labeling

Most SMD electronic components are purchased from manufacturers in the form of tubes, reels, trays and other packaging systems that feed them directly into the pick and place machine. However, assemblers need to identify them, mark them for specific projects, and label them accordingly. Automated storage systems help to sort the components in inventory so that they can be easily extracted for assembly.

2) Dispensing Solder Paste

All circuit boards that have to go through the reflow soldering process require solder paste to be dispensed in the correct position. Automated machines guide and lock the PCB and accurately position the stencil above it. The dispensing arm sprays the solder paste reel onto the stencil. The openings in the stencil allow the correct amount of solder paste to be deposited on the board below. The machine then removes the stencil and advances the board to the pick-and-place machine. The solder paste dispensing machine finely controls the amount and direction of the solder to avoid wastage. An automated SPI or solder paste inspection stage helps control failures in the solder paste dispensing stage before the board moves to the pick and place machine.

3) Pick and Place Components

The operator programs the placement machine to mount a specific PCB. They also feed the machine with the correct components. Once running, the machine positions and locks the board, picks up the correct component, and places it in the designated location on the board. Typically, the machine has multiple heads that can pick and place many components at once. Modern placement machines offer fine component handling capabilities, allowing components to be lifted, positioned, and placed in the correct location.

The process of picking and placing components is one of the processes in the entire PCB assembly sequence that requires extremely high precision and accuracy. The high degree of miniaturization of the components themselves and the mounting density of the circuit board further increase the complexity of the process.

4) Circuit Board Traceability

As a circuit board moves through an assembly line, the factory automation system tracks it as it moves from station to station. This is usually accomplished by placing tracking devices such as barcodes on the circuit board. When the PCB arrives at a station on a conveyor, a barcode scanner reads the code to track and monitor production speed. This helps identify inefficiencies in the production line and pinpoint any bottlenecks.

5) Testing

Because the circuit board assembly process is complex, post-assembly testing is critical to ensure product quality. Assemblers often employ AOI or automated optical inspection methods to identify missing, misplaced, or incorrectly installed components in the board, as well as shorts or dried solder.

Complex boards may contain various types of components that do not require optical inspection by themselves. For example, all the connection points of a BGA are located under the body of the component. They require special automated inspection methods that utilize X-rays.

Next is the in-circuit test system used to verify line continuity and interconnections between components. The test system uses various probes connected to designated test points under the board, and a programmed computer records all readings from each probe. Comparing the readings with those of a known good board verifies the integrity of the board.

Assemblers use another test system involving flying probes to verify the functionality of the assembly. Two or four probes are connected to dedicated test points on the board, while a highly technical software runs to verify that the PCB and its components are functioning properly.

Each of the above test procedures requires advanced testing capabilities, which assemblers incorporate into their test systems as needed.

6) Packaging

Thanks to the automation system of PCB assembly lines, not only the production process has been streamlined, but also the output has been greatly improved. Further automation is needed to handle the finished product, seal it and package it before sending it to the customer.

Packaging is the final stage of PCB manufacturing. This stage requires careful packing to protect the products from damage during transportation and storage. Traditional packaging is slow, labor-intensive, and prone to errors, whereas automation packaging improves speed and precision. Most packaging machines use conveyor belt systems to automatically wrap and seal the board assembly before packing it in boxes, ensuring that the products are secure during transportation.

4. Development Trends of PCB Assembly Automation

1) Automation Equipment and Robotics Technology

Automation equipment and robotics technology are important development directions in PCB assembly. The production line’s stability and dependability may be increased, human operation errors and production cycles can be decreased, and high-speed and high-precision component placement, welding, testing, and other activities can be realized using automation equipment. More flexible production layouts and production line adjustments can be made with robotics technology to accommodate the assembling requirements of items with varying models and specifications.

2) Flexible Production and Customized Needs

Intelligent and automated technologies offer greater flexibility and modification options for PCB assembly in response to the ongoing shifts in market demand and the growth of personalized customization. Production line layouts and parameters can be swiftly modified to satisfy the requirements of various product models and production batches, increasing the adaptability and flexibility of production lines, with the use of intelligent production management systems and flexible automation equipment.

3) Environmental Protection and Sustainable Development

The use of automation and intelligent technologies promotes the environmentally friendly growth of the PCB assembly industry by reducing energy consumption and waste emissions, and improving resource utilization and production efficiency.

5. Conclusion

The PCB assembly industry is increasingly embracing intelligent and automation technologies, which improve flexibility, product quality, manufacturing efficiency, and environmental sustainability. Because of the ongoing growth of technology and the development of application skills, intelligence, and automation will remain important trends in the future evolution of the PCB factory, propelling the industry as a whole to new heights.