1. Rigid-flex PCBs are not ordinary circuit boards. The process of integrating thin layers of flexible and rigid substrates into a single component presents unique challenges and opportunities.
2. When designers set out to design rigid-flex PCBs, they discovered that much of what they had previously learned about PCB design was problematic.
3. What they are designing is no longer a two-dimensional plane, but a three-dimensional internal connection that can be bent and folded.
4. I dare say this results in a more advanced PCB. Designers of rigid-flex boards replace composite printed circuit boards with multiple connectors, cables, and ribbon cables with a single component for enhanced performance and stability.
5. They limit the scope of the design to a single component, bending and folding lines like a stack of paper swans to optimize the available space.
6. Common Term: Literally, “flex circuit” seems like a replacement for multi-wired ribbon cables.
7. On top of the flexible flat substrate are the circuit layers, which are attached end-to-end. This connection is often seen between the print head and the control board of an inkjet printer.
8. In flex circuit terminology, this continuous flexibility is referred to as “dynamic flex.”
9. In dynamic flex applications, flex circuits are often (but not exclusively) single-sided to achieve high performance and strong reliability.
10. Flex circuits are used for interconnections between various subsystems, such as connecting print heads to control boards.
1. During the life cycle of a flex circuit, it must be bent, folded, and assembled with minimal deflection, which is termed “flex-to-install.”
2. Flexible installations come in various configurations, from single-layer to multi-layer, tailored to application needs.
3. Limited flexing over the circuit’s lifetime helps reduce stress on the conductor and allows for more layers.
4. For installations requiring single-sided component placement, rigid materials are strategically positioned and laminated into the flex circuit to reinforce specific areas.
5. This type of flex circuit design is known as “rigidized flex.”
6. Rigid materials (typically FR4) lack conductors and primarily serve to reinforce component base or connection areas.
7. Rigid-flex boards combine the advantages of flexible circuits and rigid materials, though they are costlier than rigid boards.
8. Rigid materials do not need to be etched or plated, only drilled and lined, which shortens PCB processing time.
9. If double-sided module installation or ultra-thin printed circuit boards are needed, a rigid-flex board may be a suitable solution.
10. A rigid-flex board features both rigid and flexible layers, making it a multi-layer printed circuit board.
11. A typical (four-layer) rigid-flex PCB has a polyimide core with copper foil on both sides, with outer rigid layers of single-sided FR4 laminated onto both sides of the flex core.
12. Although rigid-flex boards offer numerous benefits, their production is more time-consuming and costly due to the varied materials and multiple steps involved.
13. The processing of flex layers differs significantly from outer FR4 layers, requiring lamination, drilling, and electroplating, making the process 5 to 7 times longer than standard four-layer rigid PCBs.
14. Rigid-flex boards are commonly used in consumer electronics like digital cameras and MP3 players, as well as in high-end aircraft weapon navigation systems.
15. My research indicates that rigid-flex boards are prevalent in military aircraft and medical equipment.
16. In military aircraft, rigid-flex panels reduce weight and increase connection reliability, also offering the advantage of a smaller overall size.
17. Implantable medical devices, such as pacemakers and cochlear implants, benefit from the rigid-flex board’s flexibility and improved reliability.
18. Imagine if a pacemaker failed because the wire to the battery detached. The rigid-flex board allows the battery to connect directly to the circuit layer and be installed anywhere in the assembly.
19. Designers using rigid-flex boards achieve product goals by utilizing rigid designs as prototypes before transitioning to rigid-flex boards for new products.
20. For instance, an infrared system installed on a micro air vehicle or unmanned aircraft required reducing the system’s space by 50% and weight by 95%, while maintaining functionality.
21. The solution involved replacing a rigid PCB assembly with rigid-flex boards, successfully reducing the total weight from 3 pounds to under 3 ounces.
22. Jeff, who encountered rigid-flex boards for the first time, excelled throughout the design process and outsourced the PCB design to an experienced rigid-flex application designer.
23. Early involvement of PCB manufacturers and careful consideration of the higher cost of rigid-flex boards were crucial to achieving the project’s goals.
24. Rigid-flex boards’ flexibility and foldability allow for custom circuits that optimize indoor space, which, despite higher production costs, provides significant benefits in non-mass-produced designs.
25. Designing a rigid-flex panel requires understanding the manufacturing process and material properties, as standard traces from a rigid PCB may not yield the same results.
26. Polyimide’s steric stability is significantly lower than that of FR4, causing the flexible material to shrink after etching.
27. Manufacturers account for this shrinkage by closely adhering to dimensional tolerances during the machining process.
28. Designers must anticipate potential manufacturing issues and incorporate teardrops at junctions and maximize plated via ring sizes on the flex layer to achieve desired results.
29. Considerations for connecting rigid and flexible areas include supporting floating rigid areas during manufacturing and avoiding excessive removal of rigid material to prevent board fragility.
30. Die cutting is preferred for flex layers due to its suitability for thin polyimide, and no-routing areas should be included in the design tool to avoid routing components or lines over rigid edges.
31. To minimize conductor stress in flex circuits, route traces perpendicular to bend areas, avoid chamfers and width changes within bend areas, and use a grid of copper instead of solid copper.
32. For further details and design highlights, refer to the recommended reading materials on flex circuit design.
33. Some manufacturers suggest switching from rigid-flex to rigid boards due to higher costs, emphasizing the importance of early manufacturer involvement in high-volume production.
34. The main cost factors for rigid-flex boards are raw materials, board utilization, and yield, with early collaboration helping to minimize design errors and costs.
35. When choosing a supplier for flex or rigid-flex boards, evaluate their major projects and skill levels to ensure your designs align with their processing capabilities.
36. An ideal evaluation team for rigid-flex board design should include mechanical and electronic engineers, PCB designers, and PCB processing engineers.
37. Mechanical engineers address system constraints, while PCB process engineers investigate camber changes and reinforcement material additions, affecting panel numbers and production costs.
38. The cost per PCB board is inversely proportional to the number of images on the board, so designs should optimize space and production efficiency to reduce costs.
2. When designers set out to design rigid-flex PCBs, they discovered that much of what they had previously learned about PCB design was problematic.
3. What they are designing is no longer a two-dimensional plane, but a three-dimensional internal connection that can be bent and folded.
4. I dare say this results in a more advanced PCB. Designers of rigid-flex boards replace composite printed circuit boards with multiple connectors, cables, and ribbon cables with a single component for enhanced performance and stability.
5. They limit the scope of the design to a single component, bending and folding lines like a stack of paper swans to optimize the available space.
6. Common Term: Literally, “flex circuit” seems like a replacement for multi-wired ribbon cables.
7. On top of the flexible flat substrate are the circuit layers, which are attached end-to-end. This connection is often seen between the print head and the control board of an inkjet printer.
8. In flex circuit terminology, this continuous flexibility is referred to as “dynamic flex.”
9. In dynamic flex applications, flex circuits are often (but not exclusively) single-sided to achieve high performance and strong reliability.
10. Flex circuits are used for interconnections between various subsystems, such as connecting print heads to control boards.
1. During the life cycle of a flex circuit, it must be bent, folded, and assembled with minimal deflection, which is termed “flex-to-install.”
2. Flexible installations come in various configurations, from single-layer to multi-layer, tailored to application needs.
3. Limited flexing over the circuit’s lifetime helps reduce stress on the conductor and allows for more layers.
4. For installations requiring single-sided component placement, rigid materials are strategically positioned and laminated into the flex circuit to reinforce specific areas.
5. This type of flex circuit design is known as “rigidized flex.”
6. Rigid materials (typically FR4) lack conductors and primarily serve to reinforce component base or connection areas.
7. Rigid-flex boards combine the advantages of flexible circuits and rigid materials, though they are costlier than rigid boards.
8. Rigid materials do not need to be etched or plated, only drilled and lined, which shortens PCB processing time.
9. If double-sided module installation or ultra-thin printed circuit boards are needed, a rigid-flex board may be a suitable solution.
10. A rigid-flex board features both rigid and flexible layers, making it a multi-layer printed circuit board.
11. A typical (four-layer) rigid-flex PCB has a polyimide core with copper foil on both sides, with outer rigid layers of single-sided FR4 laminated onto both sides of the flex core.
12. Although rigid-flex boards offer numerous benefits, their production is more time-consuming and costly due to the varied materials and multiple steps involved.
13. The processing of flex layers differs significantly from outer FR4 layers, requiring lamination, drilling, and electroplating, making the process 5 to 7 times longer than standard four-layer rigid PCBs.
14. Rigid-flex boards are commonly used in consumer electronics like digital cameras and MP3 players, as well as in high-end aircraft weapon navigation systems.
15. My research indicates that rigid-flex boards are prevalent in military aircraft and medical equipment.
16. In military aircraft, rigid-flex panels reduce weight and increase connection reliability, also offering the advantage of a smaller overall size.
17. Implantable medical devices, such as pacemakers and cochlear implants, benefit from the rigid-flex board’s flexibility and improved reliability.
18. Imagine if a pacemaker failed because the wire to the battery detached. The rigid-flex board allows the battery to connect directly to the circuit layer and be installed anywhere in the assembly.
19. Designers using rigid-flex boards achieve product goals by utilizing rigid designs as prototypes before transitioning to rigid-flex boards for new products.
20. For instance, an infrared system installed on a micro air vehicle or unmanned aircraft required reducing the system’s space by 50% and weight by 95%, while maintaining functionality.
21. The solution involved replacing a rigid PCB assembly with rigid-flex boards, successfully reducing the total weight from 3 pounds to under 3 ounces.
22. Jeff, who encountered rigid-flex boards for the first time, excelled throughout the design process and outsourced the PCB design to an experienced rigid-flex application designer.
23. Early involvement of PCB manufacturers and careful consideration of the higher cost of rigid-flex boards were crucial to achieving the project’s goals.
24. Rigid-flex boards’ flexibility and foldability allow for custom circuits that optimize indoor space, which, despite higher production costs, provides significant benefits in non-mass-produced designs.
25. Designing a rigid-flex panel requires understanding the manufacturing process and material properties, as standard traces from a rigid PCB may not yield the same results.
26. Polyimide’s steric stability is significantly lower than that of FR4, causing the flexible material to shrink after etching.
27. Manufacturers account for this shrinkage by closely adhering to dimensional tolerances during the machining process.
28. Designers must anticipate potential manufacturing issues and incorporate teardrops at junctions and maximize plated via ring sizes on the flex layer to achieve desired results.
29. Considerations for connecting rigid and flexible areas include supporting floating rigid areas during manufacturing and avoiding excessive removal of rigid material to prevent board fragility.
30. Die cutting is preferred for flex layers due to its suitability for thin polyimide, and no-routing areas should be included in the design tool to avoid routing components or lines over rigid edges.
31. To minimize conductor stress in flex circuits, route traces perpendicular to bend areas, avoid chamfers and width changes within bend areas, and use a grid of copper instead of solid copper.
32. For further details and design highlights, refer to the recommended reading materials on flex circuit design.
33. Some manufacturers suggest switching from rigid-flex to rigid boards due to higher costs, emphasizing the importance of early manufacturer involvement in high-volume production.
34. The main cost factors for rigid-flex boards are raw materials, board utilization, and yield, with early collaboration helping to minimize design errors and costs.
35. When choosing a supplier for flex or rigid-flex boards, evaluate their major projects and skill levels to ensure your designs align with their processing capabilities.
36. An ideal evaluation team for rigid-flex board design should include mechanical and electronic engineers, PCB designers, and PCB processing engineers.
37. Mechanical engineers address system constraints, while PCB process engineers investigate camber changes and reinforcement material additions, affecting panel numbers and production costs.
38. The cost per PCB board is inversely proportional to the number of images on the board, so designs should optimize space and production efficiency to reduce costs.
