How to Determine Flex Circuit Pitch

The width of copper determines the flexibility.

Manufacturers create flex circuitry when the product demands that the circuit board has a certain amount of flexibility. The conductors are made into a type of three-dimensional circuit with a flexible dielectric. Flexible circuits are useful in the medical industry as medical implants and other devices based on how small the circuit can be created. Determine the pitch of the circuits by the size of the copper lead terminals.

Things You'll Need

• Ruler

Instructions

1. Place a ruler along the edge of the circuit that has the primary and secondary datums. This provides accurate measurement where there is less distortion due to flexible materials.

2. Measure the thickness of copper foil layers. Every 0.0007 inch of copper equals 0.5 ounces. So if you have 0.0014 inch of copper, the flex circuit has 1 ounce of copper.

3. Measure the width of the conductor. The width lets you know the pitch of the circuit, so you can determine the amount of conductivity resistance the circuit has. A circuit with a width/pitch of 0.005 inches to a 1 ounce copper foil thickness gives a circuit conductivity of 1280 milliohms.

References

• Golden Gate Graphics: Glossary of Printed Circuit Design and Manufacturing
• Medical Device and Diagnostic Industry: Microflex Circuit Applications for Medical Devices
• Printed Circuit Board and Flex Circuit Design, Development and Engineering: Practical Design Guidelines for Flex