Rugged Interconnects for Harsh Environments eBook

RESISTANCE TO HIGH TEMPERATURES Adapting cables or connectors to challenging operating conditions is also a concern for high volume products. For example, flat flexible cables (FFC) used for board-to-board connections are commonly used in many electronic devices. They are typically insulated with polyester materials that are rated to resist temperatures up to 105°C, but manufacturing processes used to connect FFC to PCBs can require a higher temperature resistance. This is the case with reflow soldering, a process during which flat flexible cables must resist temperatures up to 260°C for a few seconds. In this case, using a polyimide tape instead of polyester is highly recommended.

THIN MATERIALS FOR A BETTER FLEXIBILITY AND FLEXLIFE Flat does not mean static. Flat flexible cables can be used for dynamic applications. They have to follow the movements of moving parts and in some cases must be resistant up to 70 million flex cycles for a bend radius of 10 mm. Design engineers have to select insulating materials and conductors able to meet these severe requirements. Axon’ Cable’s proprietary, Radatox-insulated wires and cables are 10 times more resistant to ATOX and up to 40% lighter than typical perfluoropolymers (e.g., FEP, PFA, and PTFE), 100 times more ATOX-resistant than, and twice as flexible as, similar-thickness polyimide tapes, and resistant to more than 200 Mrad of radiation. Radatox insulating material can also be used for flat flexible cables.

A connection made by reflow soldering an Axon’ Flat Flexible Cable to two PCBs.

HIGH TEMPERATURE, RADIATION, AND ATOMIC OXYGEN An insulation material made with polyimide resin in the form of a tape or a jacket resists not only high temperatures but also radiation. This level of protection is required for space, energy, or research applications. In addition to radiation, atomic oxygen (ATOX) can also be a threat, especially for spacecraft operating in low earth orbit (LEO). Materials and interconnects used on spacecraft exteriors are exposed to many atmospheric conditions that can contribute to degradation. Cables and cable assemblies must be insulated with ATOX-resistant materials.

Axon’ Cable’s ultra-flexible flat cables designed for a data storage device.

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