4 Top Things You Need to Know about the PCB Manufacturing Process

Printed circuit boards (PCBs) are in essentially every kind of electronic device you can imagine these days, functioning as an integral component that provides electrical connections between different parts. 

Although PCBs are a key part of the vast majority of modern electronics, from smartphones and medical equipment to drones, they are often not built at the same time as these various devices. Indeed, they are manufactured separately, as many complex steps are involved in this manufacturing process. 

The complexity of PCB manufacturing can vary widely depending on the design and intended application, with single-layer PCBs tending to be the easiest to produce and the complexity increasing with each additional layer. 

The PCB manufacturing process involves several key stages, including designing the PCB layout using specialized software, printing the design onto a copper-coated laminate, and then etching away excess copper to reveal the circuit patterns. Additional steps, like applying solder masks, silk screens, and drilling holes for component leads, are also integral to the process.

The meticulous manufacturing process, which includes various rounds of testing and inspection, ensures that the final products are not only functional, but also durable and capable of withstanding the rigours of electronic device usage.

Top Things to Know About the PCB Manufacturing Process

The PCB manufacturing process requires much precision and care. If any parts are even slightly misplaced or mishandled, it could negatively impact performance and lead to a complete malfunction.

This manufacturing process is also incredibly interesting thanks to the various stages involved, each of which is unique and serves a different purpose. These stages include the following:

1. Design and layout

The integral first step of the PCB manufacturing process involves designing the PCB layout and schematic, which is typically done using computer-aided design (CAD) software. 

While using CAD, it is essential that technicians follow design rules and guidelines to ensure that they avoid defects that can lead to common issues, such as signal interference. 

Properly designing PCBs is also critical because it has a significant impact on the board’s electrical performance, manufacturability, and the ease with which components can be assembled. 

The design process typically begins with schematic capture, where engineers create a detailed diagram of the circuit’s electrical connections. This is followed by the layout phase, in which the components are placed on a virtual board, and the electrical connections are routed between them. 

The software then helps with routing and trace optimization, and utilizes design rule checking (DRC) features to analyze whether the design adheres to manufacturing and electrical standards. Once the design has been checked and finalized, the CAD software generates Gerber files that can be used for the PCB’s fabrication.

2. PCB materials

PCB manufacturing uses a variety of materials, each chosen to meet specific performance, reliability, and application requirements. The substrate materials, such as FR4, CEM1, and CEM3, provide the board’s structural support and electrical insulation. 

FR4 is the most common due to its balanced properties, while CEM materials offer cost-effective alternatives. Materials like PTFE or ceramic-based substrates are best for minimizing signal loss and maintaining performance. 

Conductive materials, primarily copper, form the electrical pathways of the PCB, with alternatives like silver or gold used in specialized applications to improve conductivity or corrosion resistance.

Solder masks, which are typically epoxy-based, protect the board and prevent solder bridging, while silkscreen inks provide essential labelling and markings. Additionally, thermal management materials, such as thermal pads, heat sinks, and thermal vias, are used to ensure effective heat dissipation. 

In some cases, specialty materials, including flexible substrates and high-temperature laminates, cater to specific requirements like flexibility and resistance to extreme conditions. Each material is carefully selected to ensure the PCB’s functionality and durability in its intended application.

3. Assembly and soldering

After the PCB fabrication process, components are mounted onto the board through processes like surface mount technology (SMT) or through-hole technology.

While SMT involves placing components directly onto the board's surface, through-hole technology requires inserting component leads into pre-drilled holes. With an SMT approach, reflow soldering generally follows, but wave soldering is more common when through-hole technology is used. 

For reflow soldering, solder paste is applied to the PCB’s surface pads before the components are placed. Then, the PCB is heated in a reflow oven to melt the paste, forming solder joints that electrically and mechanically connect the components to the PCB. 

On the other hand, wave soldering involves applying a flux to the PCB, inserting components into pre-drilled holes, and then passing the board through a preheat zone to activate the flux. 

The board then moves over a wave of molten solder, which flows into the component leads and creates electrical connections, followed by a cooling process that solidifies the solder joints.

4. Testing and quality control 

The only way to ensure that a PCB will function as intended and meets all design specifications, is through several rounds of rigorous testing. This typically begins with a visual inspection, often aided by an Automated Optical Inspection (AOI), to identify visible defects, such as misaligned components or solder bridges.

Then, electrical testing, including In-Circuit Testing (ICT) and functional testing, is conducted to verify that the PCB’s circuitry works correctly and performs its intended functions.

Additional testing methods, like Flying Probe Testing and Boundary Scan Testing are used for specific needs, such as low-volume runs or complex circuit analysis.

For further quality control, environmental and stress tests, including thermal cycling, humidity exposure, and vibration/shock tests, can be performed to evaluate a PCB’s durability under certain conditions. X-ray inspection can also be employed to examine a PCB’s internal solder joints and layer integrity.

How Circuits Central Can Help You Manufacture Top-Quality PCBs

If you would like to produce top-notch PCBs that are both durable and high-performing, and you require assistance with the PCB manufacturing process, Circuits Central can be of assistance. We are seasoned experts in electronics manufacturing and PCB assembly.

As a world-class electronics manufacturer, we are equipped to offer a full spectrum of electronics and PCB manufacturing services, including material procurement, schematic and PCB layout design, PCB prototyping, PCB assembly, and post-manufacturing testing and development.

With 25 years of experience under our belts and a state-of-the-art, flexible-by-design production facility at our disposal, we can handle the production of PCBs of all types and manage runs as large or as small as you need.

The PCB design and manufacturing process is full of complexity, but with our level of knowledge and expertise, we can ensure consistently high-quality end products every time. 

We can tailor our approach to meet your specific needs, no matter how stringent they are. We have helped clients from a wide variety of industries produce exceptional PCBs and electronics, and we would be happy to help you do the same.

For more information about how we can help you with PCB manufacturing, or to learn more about all our different PCB-related services, call Circuits Central at 1 (888) 602-7264 or contact us here.