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Flex PCB

PTFE Is Not a Flex Material — Physical Form, Elasticity, and What You Cannot Do With It

·1292 words·7 mins
PCB Knowledge PTFE Rogers RF PCB Flex PCB Materials PCB Manufacturing
One of the most persistent misconceptions about PTFE-based PCB laminates comes from handling the material. Pick up a sheet of Rogers RO4350B or RT/duroid 5880 and compare it to a sheet of standard FR4. The PTFE laminate feels different — slightly softer, with a quality that engineers sometimes describe as rubbery or compliant. Bend it gently and it flexes slightly before springing back. This tactile impression leads directly to a dangerous assumption: that PTFE can be used in flexible PCB applications, or treated with more mechanical freedom than a rigid board.

Polyimide Flex PCBs — Chemistry, Coverlay, and Why Flexible Solder Mask Is Not the Same Thing

·1643 words·8 mins
PCB Knowledge Flex PCB Polyimide Coverlay Materials PCB Specifications
Flex PCB specifications are among the most frequently underspecified documents in electronics procurement. Buyers write “flex PCB, polyimide base” and assume the supplier will fill in the rest correctly. Sometimes they do. Often they do not — and the failure mode is a board that cracks, delaminates, or develops intermittent opens after a few thousand flex cycles. Understanding why polyimide behaves the way it does, and why the protective layer choices matter as much as the base material, is the foundation of a correct flex PCB specification.