Keywords: Rigid Flexible PCB Manufacturer, Rigid Flex PCB

New technologies having roots in the past are sometimes encountered seemingly in electronics. Approximately back to 50 years, in spacecraft Rigid Flex PCB technologies trace to the need to replace wiring harnesses. In the first commercially available mobile computer rigid-flex technologies were used.

Few of the applications that rely on satellites, laptop computers, rigid-flex PCBs, medical devices, wearable technologies, and test equipment today.

Rigid Flex PCB

As the name implies, a combination of both rigid and flexible substrates is a rigid flex PCB. To connect sub circuits on rigid PCBs, One or more flexible circuits are used. With flexible polyimide material, rigid flex PCBs are usually produced on copper cladding substrate. To the rigid FR4 board, they are connected.

A multilayer built with padded through holes are featured by the flexible part of the rigid flex PCB securing the interconnectivity between layers. From merely using the flexible substrate to having actual sub circuits built on the flexible area itself, rigid flex PCB has grown as a replacement for wire harnesses.

Rigid Flex PCB Benefits

As compared to conventional rigid PCB, a rigid flex PCB Designing is considerably more challenging. There are some good reasons on why in some designs there is use of rigid flex and that to in which that involves fitting the board in tight spaces.

• Space Saving

Often, space is a luxury in the designs that call for a rigid flex PCB. For example, from a rigid flex PCB design, handheld thermal scanners can benefit as there isn’t much space to fit in high profile connectors and wire harnesses. Instead, you’ll have more space to route the traces around with the interconnecting circuit built-in on the flexible substrate.

• More Reliability

When there’s a need to remove the wire harness from the PCB routinely, Connectors serve their purpose. The risk of failure is increased by adding connectors to the PCB for a design involving multiple interlinking sub circuits in an enclosure. The need for board-to-board connectors is removed by implementing a rigid flex design. Sometimes prone to failure, this also leads to lesser solder joints.

• Testing Ease

As the entire sub circuits are already interconnected, it is also easy to automate testing of a rigid flex PCB when the PCB is manufactured. Before the components are assembled, the ability to eliminate connectivity issues further to prevent unnecessary expenses and wastage.

• Less Cost

As compared to their rigid counterparts, rigid flex PCBs from Rigid Flexible PCB Manufacturer are cheaper generally as the former is tougher to produce. However, the overall cost of the product is reduced by using rigid flex PCBs. You’ll save on the cost of assembly as the conductive layers of flexible material replaces wired interconnects, which involves manual labor in some cases. In the enclosure it is mounted on, there isn’t a need for installing a wire harness as a rigid flex PCB is a complete circuit on its own. For each unit of the product, such a wiring job is an additional cost and takes up precious time.

Rigid Flex PCB Design Challenges

The flexibility and versatility is off-set by various challenges allowing you to build three-dimensional products and designs. For your product to the physically stronger rigid part of the assembly, you mount the chassis, connectors, and components by the help of traditional rigid-flex PCB designs. Again, the flexible circuit only served as an interconnect in terms of traditional designs, while improving the resistance to vibration and lowering the mass.

New design rules for rigid-flex PCBs have been introduced by new product designs coupled with improved flex circuit technologies. The freedom to place components on the flexible circuit area is now present with your design team. You and your team are enabled to build more circuitry into the design by combining this freedom with a multilayer approach to rigid-flex design. However, a few challenges are added in gaining this freedom in terms of holes and routing.

For PCB designers skilled in rigid flex design, there is a pressing demand as a phase of miniaturization is being witnesses by the products. Realizing that designing a rigid flex PCB requires different skill sets is essential before you take on the challenge.

In a 3-dimensional environment, you’ll need to start envisioning the design Instead of taking a pure electrical approach. Into an enclosure, a rigid flex design is usually fitted and you must consider the mechanical elements.

To a certain degree, the flexible part of the PCB is sometimes bent. This means in the mechanical stress on the material, you’ll need to weigh. To prevent premature failure, The bend area or bend line needs to be carefully dealt with.

As the paddings are weakened by the mechanical stress, pads and vias must be avoided in the bend areas. To the bending line, Traces should also be routed perpendicularly for structural stability. To strengthen the bend area, you can add dummy traces along with the existing traces.

The flex area should have a hatched-polygon for the ground plane instead of solid copper planes. If you’re using OrCAD PCB Designer, this can be easily done. For rigid flex design, the designer must be optimized.

Design Influenced by Electromechanical Factors

Think in terms of electromechanical factors affecting both the rigid board and the flex circuit when you design rigid-flex PCBs. Focus on the ratio of bend radius to thickness as you build your design. The chances for failure are increased by an increased thickness or tight bends at the bend area with flex circuits. Keeping the bend radius at a minimum of ten times the flex-circuit material thickness is suggested by the fabricators.

Compressing it along the inner bend or stretching the flex circuit along its outer bend must be avoided. Compression at one point and stretching at another point on the flex circuit is increased by increasing the bend angle beyond 90°.

The conductor type and thickness found in the bend region is another key issue in rigid-flex reliability. By using pads-only plating and reducing the amount of plating on the conductors, you can decrease mechanical stress and thickness. The use of heavy nickel, gold, or copper plating allows mechanical fracturing and stress to occur and reduces flexibility at the bend.

Teamwork Needed by Rigid-Flex PCB Design

The ability to simulate the operation of flex circuits, visualize 3D electromechanical designs, manage multiple layer stacks, and check design rules is given by new PCB design tools to your design team. On teamwork between your fabricators and team, the successful design of a rigid-flex PCB depends even with these tools in hand.

At the earliest stages of the Rigid Flex PCB project, Teamwork must continue throughout the design hinges and process on consistent communication after beginning.