Rigid-flex Printed Circuit Board Design Curbs Wearable Healthcare Device Problems

The majority of circuit cards in today’s times are just inflexible plates for connecting circuitry. Yet, that’s changing fast; the need for flex PCBs (or flexible circuits) is promptly boosting mostly as a result of the burgeoning wearable product market. Perhaps the most significant segment of that market is the medical industry where wearable products will be helpful to collect all sorts of physiologic data for examination and research, in addition to personal health use. Witout a doubt wearables are available to keep tabs on heartbeat, blood pressure, glucose, ECG, muscle movement, and even more.


The wearable devices deliver various challenges for PC board designers that rigid boards do not. Listed below are some of the problems along with what designers can do to help remedy them.

3 Dimensional Design

While every PCB board is actually 3 dimensional, flex circuits allow the entire assy to be bent and folded to conform to the package that the merchandise takes up. The flex circuitry is collapsed in order that the rigid circuit cards fit into the product package, occupying small room.
There is a lot more to the design, so the additional challenges, than only connecting the rigid boards. Bends ought to be accurately designed so boards fall into line where they’re meant to mount, while not placing force on the connection points. Up until recently, engineers in fact used “paper doll” models to simulate the printed circuit board assy. At this moment, design tools are available offering 3D modelling of the rigid-flex assembly, helping more rapidly design and far greater accuracy.

Smaller sized Items and Compressed Circuitry

By definition, wearable products ought to be small and unobtrusive. Before, a healthcare “wearable” perhaps a Holter pulse rate monitor contained a fairly large exterior device with a neck strap or perhaps belt mount. The innovative wearables are small and attach straight away to the sufferer with no or few external wires. They accumulate many different records and are able to even process a few analyses.

An discreet device mounting straight to the patient requires flexible circuitry and incredibly dense layouts. Also, the board shapes are usually circular or even more unusual shapes, needing intelligent placement and routing. For these kinds of small and dense boards, a PC board tool that is improved for rigid-flex designs can make dealing with unconventional shapes much simpler.

Stackup Design is very important

The stackup – the map of the PCB board layers – is very important when using rigid-flex techniques. Ideally, your PCB design software has the ability to design your stackup including both the rigid and flex parts of the assembly. As mentioned previously, the layout of the flexing area should be built to help ease the stresses on the traces and pads.
One of the greatest complications with rigid-flex designs is qualifying multiple manufacturers. After the design is fully gone, all aspects of the design should be communicated to the board fabricator so it will be effectively made. Yet, the best practice is to find one or more producers early in the design and team up with them ensuring your design matches their manufacturing demands as the design moves forward. Working together with fabricators is made simple by employing standards. In this instance, IPC-2223 is the vehicle for making contact with your manufacturers.

In the event the design is finished, the data package has to be assembled to hand-off to be made. Even though Gerber continues to be employed for standard PCBs in certain firms, when it comes to the complexities of rigid-flex, it is strongly suggested by both PCB software program suppliers together with fabricators that a more intelligent data exchange format be employed. The two most widely used intelligent formats are ODG++ (version 7 or later) as well as IPC-2581, because both versions precisely define layer standards.


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