Flex circuits are being used in lots of applications today because they offer clear advantages in terms of higher circuit density combined with significant savings in weight, space and cost as compared to traditional PCB connectors, cabling, wire harnesses, etc. Flex circuits can provide up to 75% space savings compared with wiring harnesses and the low mass of flex circuits vs discrete wiring also makes flex circuits ideal for high shock, high vibration applications.
The ability of flex circuits to follow unique geometries while providing complex interconnections offers a key technology enabler for a broad range of products including:
- Smartphones, tablets and other consumer electronics
- Automotive electronics (e.g. instrument clusters, sensors, LED lighting, etc.)
- Military, aerospace and industrial
- Medical applications
The biggest challenge with flex circuits is how to efficiently and reliablity terminate the interconnects at each end of the circuit. Non-solder approaches, such as Zero Insertion Force (ZIF) connectors pose challenges in terms of space, cost and reliability, especially for applications the must withstand shock and vibration. On the other hand, traditional soldering approaches pose challenges in terms of process-control, secondary operations and yield concerns. Flex circuits typically require tight pitch, precision positioning and the use of a variety of substrates, all of which challenge the limitations of traditional soldering approaches. Sometimes manufacturers attempt to overcome these problems by raising the solder temperature but this approach has limited success and boosts the risks of damage to the flex or to sensitive components in the assembly.
In contrast, solder-bearing flex circuit contacts pre-integrate the precise amount of solder needed in exactly the right position for optimal joint formation. This enables better control of processing temperatures to avoid any risk of thermal damage to flex circuits or other components. Soldering processes can be tailored to the specific melting point of the solder alloy being used and to the specific oven/thermode parameters rather than having to overheat as a compensation technique.
Precise temperature control and pre-integrated solder is especially important to achieve consistent solder joints with ceramic substrates and/or complex geometries. For example the solder-bearing edge-clips shown below provide robust connections between the flex circuit and the underside of the ceramic substrate, while delivering 100 percent solderability using standard processing methods.
To see all of the details on leveraging Solder-Bearing Flex Circuit Contacts: Read the Tech Bulletin.
