Rigid-flex Circuit Card Design Fixes Medical Wearable Complications


The majority of circuit boards in recent times are basically rigid plates for connecting circuitry. Nevertheless, that is changing rapidly; the need for flexible PCBs (or flexible circuits) is rapidly elevating largely as a consequence of the engaging wearable device industry. Maybe the biggest segment of that market is the healthcare industry where wearable gadgets will be employed to gather all types of physiologic data for prognosis and investigation, and personal health use. Presently wearables can be obtained to keep track of heart beat, blood pressure levels, glucose, ECG, muscle movement, plus more.

Those wearable devices deliver many different challenges for circuit board designers that rigid boards do not. These are some of those problems and what designers can perform to alleviate them.

3-d Design

While every PC board is actually three-dimensional, flexible circuits permit the entire assy to be bent and folded to adapt to the package that the product takes up. The flexible circuitry is folded so that the rigid PCB boards fit in the product package, living in small space.
There is lots more to the design, so the added challenges, than only connecting the rigid boards. Bends is required to be perfectly designed so boards line up where they are intended to mount, while not putting stress on the connection points. Up until recently, engineers actually used “paper doll” models to emulate the circuit board assembly. Right now, design tools are offered that provide 3D modelling of the rigid-flex assembly, which allows quicker design and a lot greater precision.


Stackup Design is significant

The stackup – the map of the PCB board layers – is a must if you use rigid-flex techniques. If possible, your PCB design software has the capability to design your stackup including both the rigid and flexible parts of the assembly. As mentioned previously, the layout of the folding area needs to be made to lessen the pressures on the traces and pads.
One of the largest difficulties with rigid-flex designs is qualifying several makers. After the design is fully gone, every aspect of the design ought to be communicated to the board fabricator as a result it will be effectively produced. On the other hand, the best practice is to choose one or more producers at the beginning of the design and collaborate with them to be certain your design matches their manufacture specifications as the design moves on. Working together with manufacturers is simplified by utilizing standards. In such cases, IPC-2223 is the vehicle for making contact with your fabricators.

In the event the design is completed, the data package needs to be assembled to hand-off to be manufactured. Though Gerber remains to be employed for standard PCBs in a few companies, in terms of the complications of rigid-flex, it is highly recommended by both PCB program suppliers as well as fabricators that a more intelligent data exchange format be employed. The two most famous intelligent formats are ODG++ (version 7 or later) as well as IPC-2581, each of which evidently designate layer requirements.


Little Products and Squeezed Circuits

Obviously, wearable products ought to be small and very discreet. Over the past, a healthcare “wearable” such as a Holter pulse rate monitor contained a fairly large exterior device with a neck strap or maybe belt mount. The new wearables are tiny and attach right to the patient without any or few external cables. They collect a number of different info and are able to even process several analyses.

An inconspicuous device attaching straight away to the patient determines flex circuitry and very compacted layouts. Also, the board shapes are regularly round or even more uncommon shapes, requiring creative placement and routing. For this kind of small and densely-packed boards, a PCB board tool that’s optimized for rigid-flex designs helps make coping with unconventional shapes less complicated.



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