Connector Designers Face Big Challenges as Military Applications Get Smaller
By Jeff Clarke, Array Connector Corporation

As product designs for military applications become smaller and lighter, OEMs are looking for scaled-down connectors that have the same durability and reliability traditional mil-spec connectors provide. The need for higher speeds, faster data rates, and increased bandwidth means OEM system designers require more performance from input/output connectors and assemblies. This is leading to increasing usage of smaller rugged connectors for commercial interfaces, such as Ethernet, Fire Wire, USB, HDMI, and others.

The designers also want their systems to be smaller and lighter, which requires denser packaging with increased transmission speeds that can potentially increase electromagnetic interference (EMI). This problem has led to increased filtering at the board level and in cable assemblies/input/output connectors. EMI is a concern in just about any application, but particularly in airborne applications—which is where most of the attention to size and weight has been focused. One of the problems with adding filtering to a connector is that it can increase the overall size of the connector. So the challenge is to get more functionality from the interconnects, but still shrink the package size. Often, the ideal solution is to partner with a connector manufacturer that can create a custom-designed filter that fits the exact application and still meets performance, consistency, and cost considerations.

Meeting these higher speeds requires the use of better insulation materials, better shielding, and the precise twisting of wire pairs. The amount of twist, or lack thereof, is crucial in preserving and obtaining the proper data transmission speeds. Assembling these smaller-sized cable assemblies requires great skill and the use of automation, where it is available. The small wire gauges are very fragile and require special handling. The use of laser strippers is often necessary, as some of these extremely small connectors require wire gauges as small as 36 AWG. The sealing of these wires to meet environmental requirements necessitates etching in a dark room to prevent harm from ultraviolet (UV) light. All of these new issues are adding time and expense to the manufacturing of cable assemblies, while OEMs are demanding shorter lead times and lower costs.

Since most of these cable assemblies are used in harsh environments and ruggedized equipment, proper strain relief and sealing at the cable end are also concerns. These small wire gauges cannot withstand pull forces and tensions that larger-sized cables can. To protect the crimp or solder joints, it is extremely important to use a suitable strain relief, whether it is a shrink tube or a commercially available over-molded strain relief.

In the future, the challenge will fall on connector manufacturers, accessory manufacturers, and cable assembly manufacturers to provide lighter, smaller, less expensive solutions that ultimately achieve better electrical performance as it pertains to speeds, bandwidth, data rates, and EMI control. The current products that are available in the market tend to be more expensive and more difficult to assemble than traditional mil-spec connectors. Manufacturers will not only need to understand the technology, but also be able to test, measure, inspect, and verify the performance of the assemblies to make sure they meet the strict standards of the mil/aero specifications and operating environments.

As connectors become smaller, they also become more fragile and more difficult to work with. This presents additional challenges for connector manufacturers. The engineers and designers must continuously find ways to satisfy the increasing demand for smaller connectors while at the same time maintaining the same durability, environmental sealing, and ease of handling that are imperative for military applications. One example is Array’s Nano Connector product line, which uses tooled, mated pairs in aluminum, composite, and stainless steel shells to meet these requirements.

As an industry, the challenge for connector manufacturers is to keep coming up with cost-effective “out-of-the-box” solutions that maximize the performance of mil-spec interconnects as the applications they’re used in continue to shrink in size.

For more information, visit www.arrayconnector.com.