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Automotive Connector Testing: An Interview with TÜV SÜD Expert Bruce Stuart

The safety and conveniences offered in today’s generation of automobiles is due in no small part to the integration of advanced digital and electronic technologies. These technologies support the functioning of critical automotive systems and features, from antilock braking, protective airbags and driver alert sensors to state-Automotive Connector Testing - An Interview with Bruce Stuartof-the-art entertainment systems that help to keep drivers and passengers connected while traveling.

Quality connectors and connector components are essential to the seamless and trouble-free operation of these advanced systems and features. For that reason, the automotive industry has established a number of standards and specifications applicable to connectors and connector components with which connector manufacturers must demonstrate compliance. The challenge facing connector manufacturers in meeting these requirements can become even more daunting in light of proprietary connector specifications developed by some automakers.

With decades of experience in the testing of terminals and connectors used in automotive and other highly-specialized applications, TÜV SÜD’s expert Bruce Stuart has an in-depth knowledge of the complexity of testing connectors and connector components, as well as an understanding of how to adapt prescribed tests to effectively evaluate connector performance. In the following interview, Bruce shares his insights into the testing process, the typical issues encountered by connector manufacturers, and the steps that connector manufacturers can take to ensure an efficient and successful testing outcome.

Bruce, you’ve been conducting connector and connector component testing for an extended part of your career. How did you get started in this discipline?

I have been doing terminal and connector testing for my entire career (over 30 years now). I knew I wanted to work in a research field after college, but I wasn’t sure which direction to take. After graduation, I got a job working in the Product Evaluation Lab at Interlock Terminal Corporation, doing terminal crimp testing. And that was the beginning of my career.

Tell us about some of the more important issues associated with automotive connectors and connector components. How can they compromise the safety and performance of the vehicle in which they’re installed?

Terminals need to be able to perform in all climatic conditions, and the connectors holding them need to be able to protect the terminals from the harsh conditions and environments to which a vehicle is exposed. The failure of a terminal or connector system could cause any number of problems, from an audio system that doesn’t work to an anti-lock braking system failure or an airbag being disabled and not firing in a crash.

In general, what are the key aspects of connectors and connector components that are subject to testing?

I would say that the main aspects of terminal and connector testing are electrical performance, reliability over the life of the vehicle, and resistance to extremes in mechanical and environmental conditions. These are the areas on which we concentrated in automotive connector testing.

What standards and specifications are applicable to connectors and connector components used in automotive vehicles? Do all automotive manufacturers require compliance with the same connector specifications? If not, why not?

The automotive industry has developed a long list of testing specifications to ensure that all component manufacturers test products in the same manner. However, the industry group known as USCAR was formed with the idea of creating 'universal’ testing specifications that would satisfy the needs of the major automakers. Each of these companies have their own versions of these test specifications and, although they generally tend to follow the USCAR specifications pretty closely, the proprietary specifications may incorporate some unique criteria or procedures. It is exactly those small differences, and the sheer number of unique and different component designs, that make testing automotive connectors and connector components challenging.

So, given that standards and specifications applicable to the same connector can vary from manufacturer to manufacturer, that must make the process of developing a suitable test plan a real challenge. What do you think?

Component manufacturers usually have the basic idea for a test plan that would be suitable for evaluating their product because they know which tests their product needs to pass in order to be approved for use in a vehicle. But I think that the biggest issue in testing is being able to take the customer’s components, understand the intent behind each applicable test, and apply that knowledge in formulating a valid test plan for each specific component.

After all, the ultimate goal is to provide the component manufacturer and end customer with meaningful data about a component’s quality, safety and performance. Achieving this result can require developing unique testing fixtures or specially made test probes, or modifying a standardized testing procedure to fully evaluate the component in a manner consistent with the intent of the standard or specification.

When it comes to the actual testing of connectors and connector components, what are some of the typical deficiencies that you Encounter?

I would have to say that the biggest deficiency we encounter is sample quantity. In some cases, a customer doesn’t understand how many samples might be required to conduct a complete test program on their component. Since many of the tests are destructive, it is not possible to use the samples for more than a single test, and customers often fail to take that into account. Typically, we’ll discuss this issue with a customer early in the process, in an effort to establish a reasonable estimate of the quantity of samples we’ll require in advance.

Another deficiency we encounter has to do with the relationship of wire size and mechanical testing. We need to have the right sizes of conductors to conduct certain tests.

What other issues complicate the testing process? Can you share with us an example or two that helps to illustrate these Problems?

We sometimes run into issues in testing connectors and connector components that are attached to an ancillary device. For example, we recently had to perform a pressure/vacuum leak test (according to the requirements of USCAR 2, Rev 6, section 5.6.6) on a connector that was mated with a sensor module. The connectors to be tested were sealed but the module samples we received were not. We worked with the customer for several weeks to establish a protocol for sealing the modules so that they would survive the test conditions without affecting the performance of the connector being tested and thereby invalidating the test results.

What actions would you recommend that manufacturers of connectors and connector components consider taking to help expedite the testing and approval process?

It’s important for connector manufacturers to work with an experienced and qualified testing facility as early as possible during the product development process. Some components require a long lead time to produce, and knowing in advance what testing is required, as well as the sample configurations required for testing, can help to decrease the overall costs associated with that testing. All too often, I have had to take a customer’s “just built” samples and disassemble them in order to be able to use them for testing. So trying to be helpful by building samples in advance without the requisite knowledge of the testing requirements and process can backfire.

Briefly describe for us the scope of TÜV SÜD’s automotive connector testing offerings.

In our testing facility in Plymouth, Michigan, we can perform most mechanical, electrical and environmental testing for terminals and connectors used in automotive applications. Our work includes terminal crimp cross-sectional analysis and microphotography and mating/un-mating force testing, as well as thermal shock and temperature/humidity cycling and long-term electrical testing. Working with our two companion facilities here in Michigan, we can also perform vibration/mechanical shock testing, as well as fluid compatibility testing. We also have the capability to perform the connector seal retention test – unmated (as prescribed in USCAR 2 Rev 6 Section 5.4.13), which is unique among testing lab capabilities.

Finally, why should manufacturers and OEMs consider the use of TÜV SÜD’s automotive connector testing Services?

We have the advantage of a combined 60 years of automotive testing experience, dealing almost exclusively with terminals, connectors and modules of various types. We have worked with most of the major component manufacturers and many sub-suppliers in the industry, and are familiar with the testing specifications used by each of the big three automakers as well as many international specifications. We also have inhouse machining capabilities that allow us to construct specialty test fixtures as needed.

For more information about TÜV SÜD’s automotive connector testing services please contact us under automotive@tuvsud.com

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