Semi-Flex Printed Circuit Boards
Semi-Flex Printed Circuit Boards
What are semi-flex PCBs?
Semi-flex printed circuit boards are manufactured using a process which mills a section of a rigid FR4 board down to a thickness of 0.20mm +/- 0.10mm. This enables the board to be bent to fit inside a casing such as that used in automotive and data communications applications.
Semi-flex PCBs are usually used for a one-time bend installation, and multi-bend flex boards are available for those applications which require multiple bends over their lifetime.
Features of semi-flex PCBs
Cost
Compared with polyimide flex rigid boards, semi-flex is a cheaper alternative as it is only made from FR4. It avoids the need for traditional connective materials such as cables and binders, which can be expensive and increase the cost of assembly.
Reliability
Using cables or other connectors causes frequent failure but semi-flex provides a reliable alternative. Components can be mounted before the board is bent into its final position, avoiding many issues including entanglement and welding difficulties.
Time-saving
Semi-flex PCBs save time in the design phase as well as during manufacture and assembly.
Easy to fit
Semi-flex printed circuit boards can fit more easily into the final housing or box.
Semi-Flex PCB technical specification
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Layers
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1 - 12, with 1 – 2 conductive layers in the flexible section
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Technology features
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The process uses controlled depth routing of the FR-4 to achieve a flexible / bending section within a traditionally rigid FR-4 board. This is only suitable for static operations as the bends are typically just for installation.
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Bend performance
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Single Bend - Flex to Fit 0° – 90°
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Bend features
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Maximum bending angle of 90° with a 5mm radius
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Materials
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Specialised FR-4 for static flex applications
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Copper weight (finished)
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35μm
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Minimum track and gap
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Track : 0.075mm, Gap : 0.075mm
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PCB thickness in rigid section
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1.00mm – 2.00mm
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PCB thickness in flex section
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0.20mm ± 0.10mm
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Maximum dimensions
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550mm x 400mm
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Surface finishes available
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Lead Free HAL, ENIG, Immersion Silver, Immersion Tin, ENIPIG, OSP & Hard Gold
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Minimum mechanical drill
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8 mil (0.2mm) mechanical drill, 4 mil (0.1mm) laser drill
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