Flexible PCBs Contribute to Lighter Product Weight

The materials used in a printed circuit board are what make it rigid or flexible. While rigid PCBs are made of fiberglass or metal, flex boards use Polyimide or other polymer film as their base material. Using this film is important to the overall strength of the circuit board. It also contributes to its flexibility, which allows it to withstand a greater degree of bending and twisting than rigid PCBs can.

The wires in a flex PCB are another key element that help it maintain its flexibility. These copper wires allow electricity to flow between layers in the circuit board, which enables the device to work properly. There are different wire types to choose from, and some have more corrosion resistance than others. For example, gold wires are more durable than standard copper wires, and can resist higher temperatures.

A flex circuit boards thickness also affects its flexibility. While it is common for manufacturers to build a flexible circuit board with multiple layers, this can increase the cost. It’s important to consider the product’s purpose and its expected lifespan when choosing the thickness of the circuit board.

Flex circuits can be designed in a variety of shapes to suit the interior of certain applications. They are able to bend and twist without losing their integrity or snagging on components. They also don’t require an extensive framework to support them, which can be a problem for rigid PCBs.

How Flexible PCBs Contribute to Lighter Product Weight

Rigid-flex PCBs typically have a combination of rigid and flexible sections, with the rigid section providing structural integrity. The flex section is usually made of Polyimide, and is connected to the rigid section by pressure sensitive adhesives. For added durability, the flex section may have stiffeners incorporated into it, which can be made of FR-4 fiberglass.

When designing a flex circuit board, it’s important to think about mechanical stresses and possible failure points. Excessive bending and twisting can cause mechanical damage to the circuit board. This is why it’s important to carefully consider the design of a flex circuit board before sending it out for production.

For example, it’s recommended to avoid 90° bends because they increase the risk of mechanical failure. Instead, designers should aim for gradual bends with a radius greater than 30 mil. It’s also important to make sure plated through holes (PTH) are placed away from the bend area. This will prevent them from coming into contact with the copper, which can damage the flexible circuit boards during the fabrication process.

Other considerations when selecting a flex circuit board include the type of copper used and its thickness. For example, copper foils that have been electro-deposited or rolled come in a wide range of thicknesses and weights. Zinc treating the foils minimizes bond degradation and oxidation, which increases their lifespan. It’s also a good idea to opt for pad-only plating in flex circuits, as this reduces the amount of copper used and makes the board more flexible.