Designing Your Rigid-flex PCB Bend Radius with Altium Designer
Working with rigid-flex PCBs requires several design skills. You’ll need to design the right multilayer stackup, design the flex ribbon, choose the right materials, and determine how your flex ribbons will bend. When your design tools include multilayer stackup tools that include rigid-flex materials, you can easily design your rigid-flex PCBs with any number of flex ribbons. The best rigid-flex design tools should integrate directly into your routing, verification, and deliverable generation tools. Altium Designer is the only PCB design platform that includes these tools and standard features and offers true ECAD/MCAD integration.
TOPICS IN THIS SOLUTION
The only unified PCB design package with complete multilayer stackup design and native 3D design tools.
One convenient multi-board system that is easy to design is a rigid-flex PCB. These boards are useful in packaging with odd form factor or with devices that require some sort of repeated bending. Your flex ribbon will connect to the interior layers of your boards and will function as an electrical and mechanical connection simultaneously.
Since your flex ribbon will provide an electrical connection between boards, you’ll need to route connections across your flex ribbon, and you can even consider including surface-mount components at certain places on the ribbon. Flex ribbons can be designed with vias to move between the surface and inner layers, providing some of the same flexibility as rigid multilayer board.
When you include traces and components on your flex ribbon, you’ll need to carefully define the location of your bend location and the bending radius. Your bend location and radius will determine the lifetime of your board and the durability of the components. If you can carefully define the bending location and radius, you can ensure your flex ribbon can bend without damaging the electrical connection. The best way to do this is to work with design software that integrates ECAD and MCAD tools into a single program, allowing you to get a full view of the electrical connections across the bend and the structure of your board.
The flex ribbon in your rigid-flex board will integrate directly into your layer stack as a signal layer and a pair of flexible surface layers. You can also place additional signal traces, pads, and vias on flexible Printed Circuit Boards, giving you greater functionality. In some advanced boards, you’ll need to route differential pairs, surface mount components, or even a small BGA for an IC directly on your flex ribbon.
Working with a flex ribbon and ensuring components and traces on your board are not damaged under repeated bending is all about choosing the right bend radius. Determining the best bend radius to use in your board requires understanding the material properties of your flex ribbon and your traces. Conductive traces in flex ribbons can only bend so far without permanently deforming or fracturing. Working with the right design software can help you determine the right bend radius based on the stackup in your flex ribbon.
Calculating the Rigid-flex PCB Bend Radius You Need
The right bending radius for your flex ribbon depends on the stackup within the flex ribbon. A flex ribbon with more layers will have a larger minimum bending radius, and bending the ribbon beyond this minimum value will damage the flex ribbon. Working with a great design package like Altium Designer will allow you to quickly calculate the bending radius directly in your design software.
- Integrating a rigid-flex board with a flex ribbon requires defining the right stackup for your board.Learn about routing designing your layer stack for your next rigid-flex PCB.
- Designing all aspects of your rigid-flex board takes design tools with plenty of layout options. You’ll be able to design your flex zone, transition zone, and integration into your rigid board stackup.Learn more about utilizing layout options for rigid-flex design.
- Working with MCAD and ECAD tools within a single environment gives you a complete view of bending in your rigid-flex board, and allowing you to design the right packaging for your device.Learn more about working with integrated MCAD and ECAD design tools.
Schematic and 3D layout of a rigid-flex board in Altium Designer
Once you define your stackup, materials, flex region, and your bend radius, you’ll still need to get an idea of your packaging clearances, as well as clearances between boards. Just because your rigid boards do not bend does not mean that they will be flat. Large components that are present on your board can interfere with your bend, and you’ll want to ensure that your board will fit within its package.
Some PCB design programs still force you to export a model of your board to an external tool in order to verify your bending clearances. Instead of working with external software, you can easily verify clearances when you work with design software that integrates ECAD and MCAD tools into a single program.
Working With Integrated MCAD/ECAD Design Tools
Working with integrated ECAD and MCAD tools in a single interface lets you do more than just verify clearances. You’ll be able to design your board in three dimensions, offering much more detail compared to 2D tools for multilayer and rigid-flex PCB design. Integrated design software integrates tools that are normally designed to work in 2D into a native 3D design environment. You’ll be able to verify vertical and horizontal clearances, examine the structure of vias and planes, and much more.
- Your bending region is much easier to define when you have a 3D view of your entire board within your Printed Circuit design software.
- Ensuring your rigid-flex circuit board will operate correctly is all about designing the right layer stack.
- Working with integrated design tools built on a rules-driven design engine will apply your trace and net clearance rules to your 3D design tools. Your layouts will have unprecedented accuracy.Learn more about using net clearance rules in integrated design software.
The layer stackup manager with defined flex region in Altium Designer
An integrated environment unifies your electrical design tools into a single program. Your layout, component placement, stackup management, and routing tools work together with your 3D MCAD tools, giving you a full view of any board. When design software runs on top of a rules-driven design engine, you can access all your tools within a single program, giving you the power to create rigid, rigid-flex, and fully flexible boards in a single environment.
Work With the Best High Speed Design Features in Altium Designer
The design tools you need to define the right bend radius for your rigid-flex PCB, work best when placed in an integrated design environment. When your PCB design software is built on a unified rules-driven design engine, your design tools can integrate directly with your native 3D design features, and you’ll have the power to layout your circuit board in 2D and 3D. Only Altium Designer integrates these novel features into a unified environment.
- With high speed and high frequency design, it’s a good idea to implement controlled impedance design techniques. The impedance profile tools integrate directly with your stackup in Altium Designer.Learn more about multilayer impedance controlled design in Altium Designer.
- Once you’ve designed your rigid-flex board, you’ll need tools to prepare for manufacturing and assembly.See how you can plan for rigid-flex manufacturing in Altium Designer.
- Rigid-flex boards are often integrated into multi-board systems. Altium Designer’s 3D design tools will help you ensure smart mating between elements in your multi-board system.Learn more about differential pair routing Altium Designer.
Rigid-flex PCB design might seem like a complicated affair, but it doesn’t have to be when you use the right design tools. Design tools with integrated 3D design features, as well as standard routing and layout tools that operate in 3D, will easily adapt to rigid-flex PCBs. Altium Designer places all of these tools in a unified rules-driven design interface that is adaptable to any electronics application.
An integrated environment might seem like an unfamiliar design interface, and your PCB design software should help you reach success. If you are looking for helpful design tips and resources, Altium will give you access to the AltiumLive forum, webinars and podcasts, and a thorough knowledge base with design examples. You’ll be able to design for any application successfully.
With Altium Designer, you won’t have to switch between ECAD software and an external MCAD tool to define your rigid-flex PCB bend radius. Instead of using outdated command line-based design software or multiple programs to create rigid-flex PCBs. The integrated design tools in Altium Designer work together to help you create rigid-flex PCBs and integrate them into a multi-board system.