PCB expectors: The History of Flex PCBs

The History of Flex PCBs

At the beginning of the 20th century, early researchers in the burgeoning telephone industry saw the need to alternate layers of conductors and insulators to produce standardized, flexible electric circuits.

An English patent from 1903 describes coating paper with paraffin and laying flat metal conductors to provide the circuits. Around the same time, Thomas Edison’s notebooks suggested coating linen paper with cellulose gum, then tracing circuits on the gum with graphite powder.

The late 1940s brought in mass production techniques, resulting in a number of patents for photo-etching circuits on flexible substrate as a way of replacing wiring harnesses.

More recently, the addition of active as well as passive components to flexible circuits has introduced the term “flexible silicon technology,” referring to the ability to integrate semiconductors (using technologies that include thin-film transistors) onto the flexible substrate.

The combination of traditional advantages found within flexible circuit construction combined with onboard computing and sensing capability has led to exciting developments in several areas, most especially in applications in the aerospace, medical, and consumer-electronics fields.

Modern PCB manufacturers often face contradictory requirements when integrating complex circuits into a finished application.

The product needs to be light in weight, yet durable enough to survive in environments where heat, vibration and moving parts would tax traditional connections.

Additionally, manufacturing cost means that circuit integration cannot involve a lot of expensive, error-prone human assembly: it requires the repeatability and quality levels of IC design.

Finally, product lifecycles demand rapid prototyping and implementation, as time to market can make or break a product line. Flexible printed circuit boards (flex PCBs) offer advantages in all of these areas and can be used in a wide range of applications, from medical and aerospace to consumer electronics.

The Space, Weight, and Cost Savings of Flex

Redesigning a product to use flex PCBs rather than rigid PCBs deliver immediate benefits in weight. Customers commonly see weight reductions of up to 75% when compared to traditional designs.

This comes from using incredibly thin substrates made of polyester or polyimide material—films that can be as thin as 12-120 microns thick.

Conductive material traces are etched on the flex PCB, in as many layers as the PCB design requires. Typically, a coverlay is then applied to protect the layers from moisture, dirt and damage.

One important use of flex PCB design is the replacement of wiring harnesses and ribbon connectors once used to link together different boards—for example, to connect the engine control unit in an automobile to the dashboard or lighting components.

The standardization and economy of scale that goes along with this also reduces assembly cost by reducing the number of components and interconnections, and allowing for high-quality mass production.

Many flex PCB users find that they can reduce the cost of connections by up to 70% versus traditional wiring harness construction.

And with the reduction in connection cost comes a reduction in costs associated with inconsistent quality—flex PCB’s standardized construction also eliminates the source of potential errors from hand-built harnesses.

International standards have been maintained in the designing and manufacturing of new PCB series

Manufacturing of PCBs involves many complex processes and the value of various types of PCBs manufactured is dependent on the hi-tech processes. With cost efficiency and energy efficiency becoming the buzz words the end user industries are looking for smart suppliers.

Leading PCB manufacturer, HTD Circuits announced a new series of rigid as well flexible PCB. Explaining the properties of the new products, the MD said the rigid PCBs will be available in three types— single-layer, double-layer and multilayer PCBs.

He said the newly launched single-layer PCBs are significant for the high-efficiency mode with components mounted on one side of the board and the conductor patterns kept on the other side.

The double-layer PCBs have been made with complex circuits in mind and there are doubled areas for conductor patterns. More innovation has been done in ‘vias’, which are electrical ‘bridges’ functioning as holes filled with metals that touch the conductor on both sides.

Besides higher reliability, the newly launched flexible PCBs easily fits into tighter spaces without bulky connectors interfacing the other boards.

The MD said the new Flex PCBs have very fair, rugged and dependable interface. They easily fit the product into a small space and connect two rigid boards within a small space.

He said international standards have been maintained in the designing and manufacturing of new PCB series.

Reiterating that quality product and customer satisfaction as the corner stone of the company’s commitment, the MD said, the top guideline is not to deviate from established quality parameters.

Quality levels of materials are in a constant update by way of stringent testing and statistical controls. The new PCBs will serve many major segments. They include

Telecommunication, Consumer Electronics, Automation Industries, Home Security, Automobiles, Computer Applications and Lighting industry.

The Flex PCBs have been given button plating, which is larger than rigid PCBs. Each design is backed by a layout that is conducive for circuit density and line spacing. The materials are made of fibreglass called as copper clad laminate. The copper tracks have been chemically etched to connect with different components within the PCB.

To thwart counterfeiting hologram packaging has been introduced. The United States Bureau of Industry and security has reported 250 percent increase in counterfeit electrical products, especially in semiconductors.

Counterfeit parts are noted for inferior quality and decreased performance besides becoming public hazards. So, the MD said branding is important and end users have to make sure that they are procuring from an original component manufacturer or a franchised distributor.