The need for new connector and cable, or modified versions of standard interconnection systems, is growing exponentially. Highly portable electronics and the extension of their use in unique, rugged applications (often in challenging environments), are demanding new designs as well as performance. This is a period of rapid technology development, as designers create new products and instruments with higher-speed circuits that run faster, last longer, and go places we could not imagine.
Miniature microwave systems using pulse-amplitude modulation (PAM) transmit millions of bits per second. Four different voltage levels of continuous information are encoded in a series of signal pulses. Multispectral surveillance cameras also handle millions of bits per second and are connected and routed within today’s electronic systems. Innovative sensors, detectors, and monitors are dominating our militaries, unmanned vehicles, small satellites, and medical clinics.
We are experiencing great advancements in connector and cable designs to meet the challenge. Standard commercial off-the-shelf (COTS) connectors continue to be a great resource for quick prototypes and reference designs. They meet many of today’s application needs but as technologies evolve, the older standard connectors don’t always meet the design requirements. New demands often include unusual-shaped connectors, smaller sizes, low-diameter cable, and lighter weights. Well-developed prototype laboratories with specialty teams and hardware are moving in to meet that need.
Selecting Cable and Connectors
What design engineers face when selecting cable and connectors can be complex. The instrument application — where and how it is going to be used — is key. It is also critical to include a review of the overall program charter such as time to market, price, and longevity of the main product. Engineers often make a basic list of performance expectations, where and how it is going to be used, and the environment in which it will function. Second, a list of each section of the electronic signals, their voltage, and current levels can pre-set some of the items such as wire size.
Signal speed and transmission distance help as much with wire and cable design as with the connector; for example, designs for remote-controlled robotics, small satellite electronics, and soldier-worn electronics connectors to military IoT systems each have an electronic spreadsheet for every wire. Medical devices worn by patients and prosthetics have significantly different requirements such as cable insulation “feel” and limpness. Surprisingly, a gurney cable has rigorous requirements for bend and flexibility but includes structural integrity to avoid breakage when equipment is rolled over them on the floor.
Whether military or medical, electrical systems worn on humans is a rather new and advanced application area where demands are pressing designers to generate original connector designs. These small devices require connectors that reduce space and weight while increasing the instrument’s capabilities, portability, and ruggedness. Interconnect systems bear much of the wear and tear in plug-and-play systems that endure multiple disconnect and reconnect cycles as components are interchanged, and both durability and secure connectivity are paramount when cables are draped around a piece of equipment or a person.
When to Move Beyond Using Standard Connectors
One must remember that most standard designs and military specification designs have proven reliability and performance characteristics. Most of us in design work want a great match that fits and has a good history to protect our instrument. It’s recommended that you first review the established standard connector and cable that is available. If you find one that fits, use it. If, however, you find a design that is close, a great trick is to get a sample or two of the standard connectors and use them during your prototype and board building phase of the project. Simultaneously, consider what changes you need based on the proven connector in your hands.
In the past, custom design of micro and nano miniature connectors used to be perceived as expensive and painstakingly time-consuming. Today, we have fast-turn solid modeling, 3D fabrication equipment, and direct-linked CNC machinery that can speed things up significantly. Once you begin by selecting the proven and established pin-to-socket elements used in your new sample connectors, you can begin building confidence that your new device is aimed for reliability from a good history. The system design engineer can also begin an online dialog with the connector team to quickly lay out a solid model of the size, shape, and pin format needed for the new application. Changes can be made on the fly, way before cutting metal shells or developing insulator molds.
When needed, 3D additive polymer models can be made to slide into the instrument system for extra assurance that it fits and there is a route for the cable assembly. This method assures that new designs and assemblies can be completed very quickly and at significantly lower cost than before. Connector companies are staffing rapid-turn prototype laboratories with technical specialists to leverage these new capabilities and satisfy these new interconnect challenges.
How to Begin Looking for a Specialty Connector
The system designer has many first-step options available through websites and discussions with a connector salesperson, who can help by contacting a connector prototype specialist in a prototype lab before building the solid models discussed earlier. That early visit with the lab helps discover multiple options and features available in connector materials, cable format, and design shapes. Additional discussions with connector prototype and design engineers early in the process help ensure a good result in good pre-planning.
Plan for Design for Manufacturability
Review to validate or modify designs for assembly.
Review processes for low cost while meeting performance needs.
The key is to focus on the application. Connector design variations can include mixed signal with power, coax, and digital signal wiring as needed. New shapes and sizes are readily at hand. Often there is a focus on the new system and how to serve it totally with one or a minimum number of connector and cable sets. In some cases, wire can be eliminated using flex-to-connector designs that reduce weight and significantly shorten assembly time and reduce costs. For example, a device used inside anthropomorphic test dummies (ATD) to determine crash test effects on humans, is difficult to assemble using wires connected from assembly to the connector. A simple flex network improved the device significantly.
Working with an experienced connector prototype developer has proven to solve many new challenges evolving from the newer electronic capabilities coming from sensors and detectors that are being utilized in marvelous new ways. We are now highly portable and demanding massively processed data quickly. The new standard connector may be called “application-specific-driven.”
Prototype department quality and service requires resourceful engineering teams ready and willing with a list of potential solutions that includes multiple process skills as well as up-to-date knowledge of materials. It’s recommended that system designers find and work with a team that keeps those skills at hand.
Inventories of the newest materials and data can meet rugged and environmental needs. Also, the use of the newest modeling, 3D added materials, and custom machining are available. Quick-turn molding methods and hand assembly get first-article prototypes in the designer’s hand in a hurry.
This article was written by Bob Stanton, director of technology, and Travis Neumann, special projects manager, at Omnetics Connector Corp., Minneapolis, MN. For more information, visit here .