Release time：2024年7月2日
Author：Kama
A circuit board is also known as a printed circuit board (PCB).They connect circuit elements by etching conductive pathways onto a non-conductive substrate from copper foil. Understanding how a circuit board works requires an in-depth look at its design, function, and the roles of its various components.
| Substrate | The substrate is the base material of the PCB, usually made of fiberglass, epoxy resin, or other non-conductive materials. It provides mechanical support and maintains the integrity of the circuit paths. |
| Copper Layer | A thin layer of copper is coated onto the substrate. This copper is etched into conductive pathways, connecting the various electronic components on the PCB. |
| Solder Mask | The solder mask layer covers the copper layer to prevent short circuits and protect the copper traces from environmental damage. It is typically green but available in various colors. |
| Silkscreen Layer | The silkscreen layer is the top layer of the PCB, used to add labels and symbols to help assemble and understand the circuit board layout. |
| Electronic Components | Electronic components include resistors, capacitors, diodes, transistors, integrated circuits (ICs), etc., which are soldered onto the PCB. |
1.Designing the Circuit Schematic:
Use specialized software (like Eagle, Altium Designer, or KiCad) to design the circuit schematic. Designers need to determine the placement of each electronic component and their interconnections.
Consider the performance requirements of the circuit, including power distribution, signal integrity, and thermal management.
2.Generating Photomask:
After the design is complete, convert the design schematic into a photomask, a transparent film containing the circuit pattern.
The photomask is used to accurately transfer the circuit pattern onto the copper-clad substrate.
3.Preparing the Substrate and Copper Clad:
Select the appropriate substrate material, such as FR4 (fiberglass epoxy resin) or flexible materials.
Cover the substrate with a layer of copper foil, typically laminated onto the substrate.
4.Exposure and Development:
Place the photomask on the copper-clad substrate and expose it to UV light. The exposed parts of the photomask harden.
The unexposed parts remain soft, allowing for development.
5.Etching:
Use an etching solution (like ferric chloride or cupric sulfate) to remove the unhardened parts of the photomask and the underlying copper layer, leaving only the protected copper traces.
This process is done in specialized etching equipment to ensure precision and consistency.
6.Removing Photoresist:
Use specific chemical solvents to remove the hardened photoresist, leaving clear copper traces.
7.Drilling and Plating:
Drill holes in the board to accommodate through-hole components and vias (small holes connecting different layers). Use computer numerical control (CNC) drilling machines for precise positioning and sizing.
After drilling, plate a layer of copper inside the holes to ensure electrical connections between layers.
8.Applying Solder Mask and Silkscreen Layer:
Apply the solder mask layer to protect the copper traces and provide soldering points. The solder mask is usually a green solder ink.
Add the silkscreen layer to include labels and symbols for identifying and assembling electronic components.
9.Surface Treatment:
Conduct surface treatment to improve the PCB's solderability and corrosion resistance, such as Hot Air Solder Leveling (HASL), lead-free HASL, and Electroless Nickel Immersion Gold (ENIG).
10.Assembling Electronic Components:
Place electronic components on the PCB using automated pick-and-place machines or manual soldering.
Use reflow soldering or wave soldering techniques to secure components, ensuring reliable electrical connections.
11.Testing and Inspection:
Perform electrical tests on the assembled PCB to check the circuit's functionality and performance.
Use Automated Optical Inspection (AOI) and X-ray Inspection (AXI) technologies to check soldering quality and component positioning.
12.Final Assembly and Packaging:
Assemble the PCB with the casing and other necessary components to form a complete electronic product.
Conduct final testing to ensure the product meets design requirements and quality standards.
Conductive Paths: The copper traces on the PCB act as wires, creating electrical connections between components. These paths must be carefully designed to ensure proper signal flow and avoid interference.
Component Functions: Each component on the PCB has a specific function. For example, resistors control current flow, capacitors store and release electrical energy, and integrated circuits perform complex operations. The interaction between components determines the overall functionality of the electronic device.
Power Distribution: Power distribution is a crucial aspect of PCB design. Power planes, large areas of copper dedicated to providing stable voltage to components, are typically used to manage this.
Signal Integrity: Ensuring signal transmission without distortion or loss is critical for the PCB's proper operation. This involves managing impedance, crosstalk, and electromagnetic interference (EMI).
1.Single-Sided PCB: Only one side has a copper layer. It is simple and low-cost but limited in functionality, typically used in simple electronic products.
2.Double-Sided PCB: Both sides of the substrate have copper layers, allowing for more complex circuits. Components can be mounted on both sides, connected through vias.
3.Multilayer PCB: Multiple substrates and copper layers are stacked and laminated together, allowing for highly complex circuits, commonly used in advanced electronics like smartphones and computers.
4.Flexible PCB: Made of flexible materials, these can bend and twist, suitable for wearable technology and other compact devices.
5.Rigid-Flex PCB: Combining rigid and flexible parts, they offer durability and flexibility, commonly used in complex electronic devices.
High-Density Interconnect (HDI) PCB: HDI technology allows for more connections and higher component density in limited space, widely used in compact devices like smartphones and tablets.
Printed Electronics: Using conductive ink and printing techniques, flexible, transparent, and low-cost circuit boards can be manufactured for IoT devices, wearables, and more.
Optoelectronic PCB: Integrating fiber optic technology for high-speed data transmission, used in communication devices and data centers.
Thermal Management: As power density in electronic components increases, thermal management technology becomes crucial. Using thermal conductive materials and structural design helps dissipate heat and improve device reliability.
Market Growth: According to market research, the global PCB market was approximately $60 billion in 2020, expected to reach $75 billion by 2025, driven by the rapid development of consumer electronics, automotive electronics, and communication technology.
Component Miniaturization: As devices become smaller, so do the components on PCBs. Surface-mount technology (SMT) allows components to be placed directly on the board's surface, saving space and improving performance.
Environmental Technology: PCB manufacturing may involve harmful chemicals and electronic waste. Efforts are being made to develop more environmentally friendly materials and recycling methods to reduce environmental impact.
Circuit boards are the foundation of modern electronic devices, enabling the creation of compact, reliable, and complex equipment. Understanding how circuit boards work provides foundational knowledge for deeper exploration and application of modern technology. As technology advances and market demands change, circuit boards will continue to play a key role in the development of electronic devices.
At Huaxing PCBA Factory, we pride ourselves on our commitment to providing PCBA solutions that consistently meet and exceed the highest industry standards. Our strong Quality Management System (QMS) and great pricing are the cornerstones of our operations, ensuring that every product leaving our facility is of the highest quality.
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