1. The advantages of PCB flexible printed circuit boards
2. PCB flexible circuit boards are designed to improve space utilization and product design flexibility, meet the design needs of smaller and higher density installations, and also help reduce assembly processes and enhance reliability.
3. It is the only solution to meet the requirements of miniaturization and mobility of electronic products.
4. Flexible circuit boards are copper circuit boards etched on polymer substrates, or printed polymer thick film circuit boards.
5. Design solutions for thin, lightweight, compact and complex devices range from single-sided conductive traces to complex multi-layer three-dimensional packaging.
6. The total mass and volume of the flexible package can be reduced by 70% compared to the traditional element wire harness method.
7. Flexible circuit boards can also be increased in strength through the use of reinforcing materials or liners for additional mechanical stability.
8. PCB flexible circuit boards can be moved, bent, twisted without damaging the wires, and can have different shapes and special package sizes.
9. Its only limitation is the volume space issue. With the ability to withstand millions of dynamic flexures, flexible circuit boards are well suited for continuous or periodic motion in interconnecting systems as part of the final product functionality.
10. Some products that require electrical signal/power mobility and smaller form factor/package size benefit from flexible circuit boards.
11. PCB flexible circuit boards provide excellent electrical properties.
12. A lower dielectric constant allows for fast transmission of electrical signals; good thermal properties allow components to cool down easily; and a higher glass transition temperature, or melting point, allows components to perform well at higher temperatures.
13. Flexible circuit boards can provide higher assembly reliability and yield by reducing the hardware required for interconnection, such as solder joints, trunks, backplane lines and cables commonly found on traditional electronic packages.
14. Because the traditional interconnection hardware composed of complex multiple systems is prone to a high component dislocation rate during assembly.
15. With the advent of quality engineering, a thin, flexible system is designed to be assembled in only one way, eliminating the human error typically associated with independent wiring engineering.
16. Early flexible circuit boards were mainly used in the fields of small or thin electronic products and connections between rigid printed boards.
17. In the late 1970s, it was gradually applied to electronic products such as computers, digital cameras, inkjet printers, car audio, CD-ROM drives (see Figure 13-1) and hard disk drives.
18. Turn on a 35mm camera and there are 9-14 different flexible circuit boards inside.
19. The only way to reduce size is to have smaller components, finer lines, tighter pitches, and bendable objects.
20. Pacemakers, medical devices, video cameras, hearing aids, laptops—just about everything used today has flexible circuit boards inside.
21. The double-sided flexible board is a conductive pattern made by etching on both sides of the insulating base film.
22. The metallized hole connects the patterns on both sides of the insulating material to form a conductive path to meet the flexible design and use function.
23. The cover film protects single and double-sided conductors and indicates where the components are placed.
2、The function of PCB flexible circuit boards
2.1 Flexibility and reliability of PCB flexible printed circuit boards
1) Single-sided flexible boards are cost-effective solutions for applications not demanding high electrical performance. These boards feature chemically etched conductive patterns on a flexible insulating substrate, typically with rolled copper foil. Materials like polyimide, polyethylene terephthalate, aramid, and polyvinyl chloride are common choices for the insulating substrate.
2) Double-sided flexible boards entail conductive patterns etched on both sides of the insulating base film. Metallized holes connect the patterns on both sides, forming a conductive path. A cover film protects the conductors and aids in component placement indication.
3) Multi-layer flexible boards involve laminating single-sided or double-sided flexible circuit boards together, creating conductive paths between different layers through metallized holes. These boards offer higher reliability, better thermal conductivity, and easier assembly compared to single-sided or double-sided boards.
4) Traditional rigid-flex boards combine rigid and flexible substrates. They feature a compact structure with metallized holes for conductive connections. Rigid-flex boards are suitable when components are located on both sides; otherwise, double-sided flexible boards with FR-4 reinforcement on the back are more economical.
The PCB flexible circuit board industry is experiencing rapid development, with the polymer thick film method emerging as an efficient and cost-effective production process. This method involves selectively screen printing conductive polymer inks on flexible substrates like PET, eliminating the need for etching. Polymer thick film circuit boards are significantly cheaper than copper polyimide film and rigid circuit boards, making them ideal for control panels, mobile phones, and portable products, where components, switches, and lighting devices can be converted to polymer thick film circuit boards, reducing costs and energy consumption.
5) PCB flexible circuit boards with a mixed structure feature a conductive layer composed of different metals. This hybrid structure is primarily used in low-temperature environments where electrical signal conversion and heat conversion require careful consideration. The choice between interconnected designs should prioritize performance and cost-effectiveness.
2.2 The economy of PCB flexible circuit boards
For relatively simple circuit board designs with small volumes and suitable spaces, traditional interconnection methods are generally more economical. However, for complex circuits handling multiple signals or requiring special electrical or mechanical performance, flexible circuit boards offer a better design choice. Flexible assembly becomes economical when applications surpass the capabilities of rigid circuit boards. The use of flexible materials eliminates the need for connectors, contributing to cost savings. Despite the higher raw material costs and manufacturing challenges associated with flexible circuit boards, their foldable, bendable, and multi-layer capabilities reduce overall assembly size and material usage, thereby lowering total assembly costs.
In summary, while PCB flexible circuit boards may be initially more expensive and challenging to manufacture compared to rigid circuit boards, advancements in materials, production processes, and structures are driving down costs and closing the price gap. Flexible circuit boards will continue to play a crucial role in various industries, particularly in meeting demands for smaller, more complex assemblies and lead-free applications.
2. PCB flexible circuit boards are designed to improve space utilization and product design flexibility, meet the design needs of smaller and higher density installations, and also help reduce assembly processes and enhance reliability.
3. It is the only solution to meet the requirements of miniaturization and mobility of electronic products.
4. Flexible circuit boards are copper circuit boards etched on polymer substrates, or printed polymer thick film circuit boards.
5. Design solutions for thin, lightweight, compact and complex devices range from single-sided conductive traces to complex multi-layer three-dimensional packaging.
6. The total mass and volume of the flexible package can be reduced by 70% compared to the traditional element wire harness method.
7. Flexible circuit boards can also be increased in strength through the use of reinforcing materials or liners for additional mechanical stability.
8. PCB flexible circuit boards can be moved, bent, twisted without damaging the wires, and can have different shapes and special package sizes.
9. Its only limitation is the volume space issue. With the ability to withstand millions of dynamic flexures, flexible circuit boards are well suited for continuous or periodic motion in interconnecting systems as part of the final product functionality.
10. Some products that require electrical signal/power mobility and smaller form factor/package size benefit from flexible circuit boards.
11. PCB flexible circuit boards provide excellent electrical properties.
12. A lower dielectric constant allows for fast transmission of electrical signals; good thermal properties allow components to cool down easily; and a higher glass transition temperature, or melting point, allows components to perform well at higher temperatures.
13. Flexible circuit boards can provide higher assembly reliability and yield by reducing the hardware required for interconnection, such as solder joints, trunks, backplane lines and cables commonly found on traditional electronic packages.
14. Because the traditional interconnection hardware composed of complex multiple systems is prone to a high component dislocation rate during assembly.
15. With the advent of quality engineering, a thin, flexible system is designed to be assembled in only one way, eliminating the human error typically associated with independent wiring engineering.
16. Early flexible circuit boards were mainly used in the fields of small or thin electronic products and connections between rigid printed boards.
17. In the late 1970s, it was gradually applied to electronic products such as computers, digital cameras, inkjet printers, car audio, CD-ROM drives (see Figure 13-1) and hard disk drives.
18. Turn on a 35mm camera and there are 9-14 different flexible circuit boards inside.
19. The only way to reduce size is to have smaller components, finer lines, tighter pitches, and bendable objects.
20. Pacemakers, medical devices, video cameras, hearing aids, laptops—just about everything used today has flexible circuit boards inside.
21. The double-sided flexible board is a conductive pattern made by etching on both sides of the insulating base film.
22. The metallized hole connects the patterns on both sides of the insulating material to form a conductive path to meet the flexible design and use function.
23. The cover film protects single and double-sided conductors and indicates where the components are placed.
2、The function of PCB flexible circuit boards
2.1 Flexibility and reliability of PCB flexible printed circuit boards
1) Single-sided flexible boards are cost-effective solutions for applications not demanding high electrical performance. These boards feature chemically etched conductive patterns on a flexible insulating substrate, typically with rolled copper foil. Materials like polyimide, polyethylene terephthalate, aramid, and polyvinyl chloride are common choices for the insulating substrate.
2) Double-sided flexible boards entail conductive patterns etched on both sides of the insulating base film. Metallized holes connect the patterns on both sides, forming a conductive path. A cover film protects the conductors and aids in component placement indication.
3) Multi-layer flexible boards involve laminating single-sided or double-sided flexible circuit boards together, creating conductive paths between different layers through metallized holes. These boards offer higher reliability, better thermal conductivity, and easier assembly compared to single-sided or double-sided boards.
4) Traditional rigid-flex boards combine rigid and flexible substrates. They feature a compact structure with metallized holes for conductive connections. Rigid-flex boards are suitable when components are located on both sides; otherwise, double-sided flexible boards with FR-4 reinforcement on the back are more economical.
The PCB flexible circuit board industry is experiencing rapid development, with the polymer thick film method emerging as an efficient and cost-effective production process. This method involves selectively screen printing conductive polymer inks on flexible substrates like PET, eliminating the need for etching. Polymer thick film circuit boards are significantly cheaper than copper polyimide film and rigid circuit boards, making them ideal for control panels, mobile phones, and portable products, where components, switches, and lighting devices can be converted to polymer thick film circuit boards, reducing costs and energy consumption.
5) PCB flexible circuit boards with a mixed structure feature a conductive layer composed of different metals. This hybrid structure is primarily used in low-temperature environments where electrical signal conversion and heat conversion require careful consideration. The choice between interconnected designs should prioritize performance and cost-effectiveness.
2.2 The economy of PCB flexible circuit boards
For relatively simple circuit board designs with small volumes and suitable spaces, traditional interconnection methods are generally more economical. However, for complex circuits handling multiple signals or requiring special electrical or mechanical performance, flexible circuit boards offer a better design choice. Flexible assembly becomes economical when applications surpass the capabilities of rigid circuit boards. The use of flexible materials eliminates the need for connectors, contributing to cost savings. Despite the higher raw material costs and manufacturing challenges associated with flexible circuit boards, their foldable, bendable, and multi-layer capabilities reduce overall assembly size and material usage, thereby lowering total assembly costs.
In summary, while PCB flexible circuit boards may be initially more expensive and challenging to manufacture compared to rigid circuit boards, advancements in materials, production processes, and structures are driving down costs and closing the price gap. Flexible circuit boards will continue to play a crucial role in various industries, particularly in meeting demands for smaller, more complex assemblies and lead-free applications.
