best suited for designing rigid flex boards
Rigid flex boards offer a great solution for your Printed Circuit Board needs. Designed in 3D, they can be bent and twisted to fit your product’s shape. With thin copper layers and adhesive-less laminates, rigid flex boards are also very light. These factors make them a great option for any space-efficient applications, such as wearables or foldable devices.
Like traditional PCBs, rigid flex boards are composed of a series of layers stacked on top of each other. However, unlike standard PCBs where the X-Y plane defines the layers and the layer stackup, rigid flex boards can have more than one zone or “Region”. Each Region can use its own unique layer stack up. This is achieved by using the Zone Editor. Zones are defined in the Cross Section Editor and can include both rigid zones and flex zones. Each zone can also have associated keepouts, constraint regions or rooms and optional flex or mask layers.
Creating a multilayer design for a rigid flex board starts with the Zone Editor in the Cross Section Editor. To create a new zone, select “New” from the “Zone” menu and enter in the required data. This includes a name for the zone as well as the conductor and non-conductor layers that need to be used in that particular zone. For example, a rigid zone might require 10 conductor layers with soldermask and a flex zone could contain two conductors and several mask layers such as coverlay or adhesives. The Zone Editor can then automatically generate the primary and flex stackups.
What design software is best suited for designing rigid flex boards?
Once you’ve configured the Zone Editor, it is time to move on to the Layer Stack Manager in the main design window. The Layer Stack Manager shows the current layer stack for your rigid flex board and provides a visual representation of how the layers are arranged. It can also be modified and expanded to show the full layer stack for your flex or rigid-flex PCB.
When designing a rigid flex, it is important to consider the thermal performance of your design. Ensure that ground and signal layers are separated from each other to prevent EMI coupling between components. It is also a good idea to incorporate hatched ground planes to reduce the size of vias on your design.
The mechanical reliability of rigid flex boards is another important consideration. Flex boards are more prone to vibration and bending than their rigid counterparts, so it is critical to work closely with fabricators to ensure that the flexible sections of your board can handle this mechanical stress without failing.
Creating a rigid-flex or flex circuit can be daunting, but with the right design tools and layout techniques it’s not as complex as it may seem at first glance. A unified design platform such as Altium Designer provides you with integrated ECAD and MCAD tools that are adaptable to rigid-flex and flex designs. It also allows you to quickly verify your clearances with standard mechanical tools that are already built into the unified design model.
