3D adds flexibility
Designing a flexible PCB and making it fit into a complex mechanical housing is a significant challenge. It requires using a sophisticated application of mechanical and electronic CAD tools in order to address the design challenges and removing data exchange limitations. Using CATIA 3D Flexible PCB Design, the end-to-end process is 100-percent digital. There are no workflow breaks or manual operations – figure 1
Figure 1: The end to end 3D design process in CATIA
A typical use case scenario is to design the mechanical housing, including the shape of the flex board using CATIA. Hardware assemblies containing rigid and flexible boards, and mechanical components are developed first. The flexible PCB board outline is created by mechanical designers using CATIA which also acts as a unified repository for evolving designs.
This means that the PCB board designs created in CATIA remain as digital models throughout their development cycle. The PCB board outlines can be flattened and folded back to their original 3D position.
Figure 2: Critical components are placed in 3D to ensure they respect the mechanical design constraints.
Critical components are placed in 3D and thereby benefit from a 3D virtual mock-up of the product. This allows them to be located on the board in the correct location, first time – see figure 2.
In many cases stiffeners will be added to the 3D virtual board model. Constraint areas are then added in 3D and the flexible PCB board is flattened using CATIA.
This flattened view of the flexible PCB contains all 3D design information, along with the components and constraint areas. Data is exchanged with the electronic designers and the flexible PCB model is translated to ECAD via an IDF file. All remaining electrical components are placed and coppers/wires are routed in ECAD.
Electronic circuit design and electrical constraints are forward-annotated to the flex board shape and the board outline is created. Automatic placement of electronic components and routing is available. After completion of the board layout, design rule checks are applied, and the board layout is forwarded to the MCAD system. Comparing this new design to the previous one, and updating the MCAD session is key to increasing user efficiency.
Components and copper traces are imported and added to the design and then folded back to their 3D position. Finally, the flexible PCB can be validated against the full 3D virtual mock-up – see figure 3
Fig. 3: The flexible PCB can be validated against the full 3D virtual mock-up.