Developing Custom Connectors for the Automotive Market

Although there are dozens of standard, off-the-shelf automotive connectors deployed in each new vehicle, the recent integration of evolved electronics in automotive designs has resulted in a rapidly growing population of custom connectors that make complex electric systems communicate effectively.

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What we once thought was leading-edge technology is now common in our everyday lives. Take a multi-million dollar fighter jet, for example. If you climbed into the pilot’s seat, you’d see an electronics-packed cockpit full of multiple onboard computers and displays for radar, night vision, collision avoidance, autopilot, and flight/engine management systems, among others. If you then slid into the driver’s seat of a new, high-end automobile, you’d have almost all of the same electronic systems at your fingertips – aside from those that allow you to take flight, that is.

How is this possible? Well, the now-striking similarities between the electronics systems in aircraft and automobiles are due in part to the revolutionary connector technologies that have evolved to keep pace with the cutting-edge electronic systems and sensor technologies that have been developed for and integrated into the cost-effective, volume-based onboard systems designed into advanced automobile technology. Although there are still dozens of standard, off-the-shelf automotive connectors deployed in each new vehicle, the recent integration of evolved electronics in automotive designs has resulted in a rapidly growing population of custom connectors that are required to make these complex electric systems communicate effectively.

What were once heavy and costly metal die-cast boxes packed with computer electronics are now made from plastic, featuring insert-molded headers to provide protection from any moisture ingress, and often employ dual-shot molding techniques to integrate lid-to-body gasket sealing. The input/output density and pin-count in these engine or transmission control units continue to push the envelope as more engine, transmission, environmental, and stability sensors are added to funnel real-time data from every electronic system in the vehicle into the main computer – just like in a fighter jet.

The connectors inside these boxes are even more complex. Mechatronics has emerged as a new technology that effectively integrates traditional connector functionality and an unlimited number of electromechanical components and processes into a higher-level subassembly. This provides systems suppliers with a drastically improved value-added component that is fully inspected and tested and – better yet – designed to quickly and easily fit into a complex automated assembly line. The transition from high-performance, low-production-volume fighter jets to mass-produced automobiles required traditional single-function connector technology to evolve into multi-function components.

For example, electrolytic capacitors (ECs) are used in several vehicle electronics systems to store electrical energy because they offer a much higher capacitance level than smaller ceramic or tantalum capacitors; however, they cannot survive the reflow temperatures in the SMT board assembly process. Instead, ECs must be soldered onto the PCB in a secondary process that adds cost and often exhibits solder process variations. The solution, which has already been deployed in many of the millions of vehicles shipped each year, was to develop a cradle that could mechanically hold the EC while also providing the electrical connection to the board.

In a previous article, “Working with Custom Connector Suppliers,” we discussed how new off-the-shelf connectors are typically developed based on each connector company’s existing, proven contact technologies. So, when presented with the challenge of developing a connector capable of both affixing an EC to a board and establishing a reliable electrical connection, that’s exactly what we did.

For many years, AVX has supplied both press-fit (e.g., compliant-pin) and insulation displacement connector (IDC) technology for the automotive market. Simply put, these are two of the most robust and reliable contact systems available. Both of these contacts utilize phosphor bronze material that can then be stamped from a single base material. In this application, the termination process presses the solid leads of the EC into the IDC tines, and then presses the final capacitor carrier onto the PCB, creating cold-welded solder joints that provide ultimate reliability in harsh, mission-critical automotive applications, such as airbag, engine, and transmission computers. Figures 1 and 2 illustrate what a typical custom connector or electronic module looks like.

Custom Connector design

Figure 1

Standard automotive-grade connectors have a solid home inside the vehicle for infotainment, navigation, lighting, seat management, and other similar systems. Custom connectors aren’t typically required until they move beyond electronics systems that manage things like temperature-controlled seats and are instead exposed to constant weather, vibration, and temperature extremes in under-hood environments. This is why the material selection, assembly process, and critical dimension discussions that take place during the connector feasibility reports that tend to precede volume delivery by one to two years are so important. Consumers expect the electrical systems that are responsible for more and more automotive functions each year to work for the life of the vehicle, and the connectors in these systems play a critical part in meeting this expectation.

Custom connectors - electronic modules

Figure 2

Beyond critical metal and plastic or molding and stamping selections, one of the biggest challenges for connector suppliers has been the development of their own automation systems. Contacts are no longer just stitched into a housing. Robots and vision systems are critical for being able to bring multiple sub-components and processes together in a final, fully functional and tested module that’s ready to go directly into customers’ assembly lines.

Developing custom automotive connectors is challenging because it requires connector designers to constantly evaluate new materials and processes in anticipation of meeting future system demands, but it is also rewarding. While it differs for various systems and platforms, each automobile produced today likely has in excess of 25 custom connectors or mechatronic assemblies that provide the necessary electrical and mechanical integration in fully automated assembly processes.

Author Tom Anderson, connector product manager for AVX, has been in the connector industry for more than 30 years and has held a variety of product marketing positions. For the last 10 years he has focused on developing new connector technologies for the automotive, industrial, and solid-state lighting markets. He can be reached at tom.anderson@avx.com.

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