The flex PCB stackup documentation is an important component of the data set of a flexible printed circuit board design. It consists of a description of a flex or rigid-flex circuit board that defines in detail the specific material requirements and construction of the design.
Many electronics assemblies that utilize flexible printed circuit boards are sensitive to either absorbing or emitting electromagnetic interference (EMI). If EMI is left uncontrolled it can negatively impact the performance of the design and in extreme cases completely prevent it from functioning.
The pre-baking of flex printed circuit boards (PCB) immediately prior to assembly is an industry standard requirement that is documented in IPC2223 sec 5.3.5, IPC-FA-251 sec. 220.127.116.11.2 and by material suppliers (i.e. DuPont Pyralux Technical Manual sec. 5.23). This applies to all polyimide-based flex and rigid–flex designs. But why is pre-baking done prior to assembly, rather than earlier in the circuit board manufacturing stage?
When ordering flex circuit boards online, quick turn order delivery timelines can incur setbacks if the data set is either incomplete or if the design has technical issues. Technical issues can be related to either manufacturability or the end use of the parts. These issues then often require multiple communications to resolve and in some worst-case scenarios, extensive design revision. Any of these issues will of course delay the delivery of the finished parts.
Flex circuit suppliers come in a variety of different sizes and stages of financial integrity. Choosing the one that will perform the best for your requirements is an important element to the success of you application. Knowing what questions to ask your flex circuit supplier is essential in choosing who will be manufacturing your flex circuits.
For every flexible circuit board manufacturer, there are some key areas you should be aware of. While flex circuits have some similar characteristics to rigid printed circuit boards, they require very different approaches in the manufacturing process.
In the world of flexible circuit boards, stiffeners are a common requirement in a lot of flex designs. By definition, a circuit board stiffener provides a mechanical support function and is not part of the electrical schematic of a design.
It is critical for any flex circuit design to be free of errors and violations in order to get the application to market as fast as possible without unnecessary delay. To help designers avoid common IPC PCB design standards violations in rigid-flex PCBs, this blog post will discuss three of the most common IPC Association Connecting Electronics Industries design violations.
One question we get asked frequently is: "Why does flex and rigid-flex PCB tooling cost more than rigid PCBs?" The answer is quite simple; flex circuit tooling is a much more complex process than standard printed circuit boards.
Previously, we gave you the definition for flexible circuit coverlay. Now, we go into greater depth discussing the two primary options for encapsulating the external circuit layers of a flex circuit: polyimide coverlay and flexible liquid photoimageable (LPI) solder mask. The two materials have very different capabilities and requirements.