Design Guidance

2022-11-08 BEST

Flexible PCB Advantages

High Reliability

Flexible PCB Advantages Flexible printed circuit boards have several advantages over rigid PCBs. They include, but are not limited to: Ease of form, Fit and Function.

Ease of Use:

• Design constraints are minimal. PCBs can be designed to fit any device shape.

• Range of motion allows PCBs to suit nearly any application.

• Less mass reduces risk in environments with regular vibrations.

• Reduces errors found in standard PCB assemblies.

• Reduces weight through the elimination of additional wires, cables and connectors.

Reducing PCB Size: 

• Thinner and more lightweight than their rigid alternatives (FR4 PCB).

• Durable against motion and bending.

• HDI allows for the miniaturization of devices.

Repeatable installation

Compared to discrete wiring, or ribbon cable, a flex circuit offers a customized repeatable routing path within your assembly. This gives you dependability where you need it. A flex circuit’s longevity can reduce service calls.

Harsh environments

Standard practice for flex boards is to cover the conductors with Polyimide (refers to PI in later sentence). This dielectric layer protects your circuits far beyond the capability of simple soldermask. Other base and cover materials are available for a broad range of ambient conditions.

Long duty cycles

By design, a flex circuit can be made very thin, yet robust enough to withstand thousands to millions of flexing cycles while carrying signal and power without a break.

High vibration

Under vibration and/or high acceleration, a flex circuit’s ductility and low mass will reduce the impact upon itself and solder joints. By contrast, a PCB’s higher vibrational mass will increase stresses upon itself, its components and solder joints.

Superior packaging options

Flex circuits can be shaped to fit where no other design can. They are a hybrid of ordinary printed circuit boards (PCB) and round wire, exhibiting benefits of each. In essence, flex circuits give you unlimited freedom of packaging geometry while retaining the precision density and repeatability of printed circuits.

Flex VS wiring harness

•Space and weight reduction: A single flex circuit can replace several hard boards, cables, and connectors.

•Fast assembly: Flex circuits eliminate the need to color code and wrap bundles of wire, reducing the chance of assembly rejects and in-service failures. Total installed costs are lower, especially with volume production.

•Repeatable wire routing: Eliminate wire routing errors; reducing test time, rework, and rejects

•Robust connections: Flat foil conductors dissipate heat better, carrying more current than round wires of the same cross-sectional area. Conductor patterns in a flex circuit maintain uniform electrical characteristics. Noise, crosstalk, and impedance can be predicted and controlled.

Flex VS Rigid board (PCB)

•Versatile shape: The most important attribute compelling designers adopt flex circuit technology is the capability of the flex circuit to assume three-dimensional configurations.

•Lower mass: With a little experimentation and imagination, a flex circuit can save up to 75% of the space and/or weight of conventional wiring.

•Vibration resistance: Recurring costs are lower than many wire harnesses, and since a flex circuit is more resistant to shock and vibrations than a PCB, repairing and replacement costs are less than PCB.

•Flexible Circuit or Round Wire

Perhaps a short review of the advantages of flexible circuitry will help you make a decision.
1. Less weight and bulk when used as a direct round wire replacement.
2. It will virtually eliminate wiring errors and subsequently the need for troubleshooting wiring errors.
3. When all the costs of manufacturing, assembly, installation, and troubleshooting/repair are considered, a lower “end-use cost” is usually obtained with flexible circuitry.
4. Greater environmental resistance against corrosion, moisture and other atmosphere hazards because of the encapsulation of the copper conductors.
5. Improved durability because the materials used are highly resistant to flexing and tension.
6. Better adaptability. Able to fit into operational configurations where printed circuit boards simply cannot fit.