The importance of
flexible circuits in industries is increasing every day. This is due to the
constant changes taking place in the electronic device manufacturing industry. As
electronic device designs continue to become smaller and lighter, the
requirement for flexible circuits will continue to grow. This also means that
the circuits can be used in varied electronic applications in markets such as consumer,
industrial, military, medicine, and aerospace.
Most of the above
mentioned markets will have dynamic applications that require effective
flexible circuits boards products. That is why it is important for an electronic designer to understand
the technology and know when and where it needs to be used.
Design
Considerations for Flexible Circuits
In dynamic flex
applications, the designer needs to incorporate certain design practices that
will help to enhance the flex circuit’s service life
- Use only Rolled Annealed Copper: This is an important point to consider when creating panels. Rolled annealed copper allows for the flexing motion to be lateral with the grain direction of the copper.
- Create Neutral Copper Traces: The term ‘neutral’ here means that the amount of copper has to be equivalent to the dielectric on either side of the traces. This will prevent the copper from compressing during flexion.
- Maintain a Gentle Bend Radius: In dynamic applications, the bend radius should be 10 times the thickness of the material. For example, if a single sided circuit has a thickness of .005", then the appropriate bend radius would be .050".
- Incorporate Pads only Plating: This is used only for double sided circuits. The bend regions of the circuits should be fabricated with only a single layer of copper, and not with electroplated copper. This will allow for neutral flexing of the axis.
These
are some important guidelines that any electronic designer can use as rule of
thumb when designing flexible circuits for dynamic applications.
