Common Errors in Leak Testing Automotive Parts

Top 10 Errors

In our e-book Leak Testing in the Automotive Industry, the top 10 most common errors made by vehicle manufacturers and automotive suppliers when testing for leaks is discussed. These errors can result in tests that will yield some results, but will not provide the information you need to determine if a part is leaking, or not.

No bubbles - no leak?

If the operator of a water bath does not see any bubbles, it would appear that there is no leak. However, very often this is not true. One fundamental requirement for every detection method is that the minimum detectable leak rate is sufficient for this application scenario. Surprisingly, in real life applications this is often neglected. For example, plastic parts are tested via pressure decay without taking into account that these are deformed and change their volume when filled with pressurized air. Or parts are tested with helium in a vacuum chamber to very small leak rates, but for localizing the leaks, the parts are tested in a water bath. To ensure that leaks detected in the vacuum chamber can be localized with sufficient sensitivity, it is best to use sniffer leak detection with tracer gas.

Finding stringer leaks takes time

Stringer leaks, consisting of long capillary shaped cavities, can pose a problem for airbag manufacturers, as well as other component manufacturers. If the time between filling with tracer gas and actual leak testing is very short, the tracer gas cannot fully fill the leak channel and escape from the stringer leak opening. The exact opposite is true for gross leaks. If the part shows a gross leak, all tracer gas may have already escaped from the part by the time of testing. Another consequence of a gross leak, may be that the part is evacuated from tracer gas at the same time when evacuating the chamber. As a result of any of these scenarios the part is tested as NO LEAK.

Learn more about the Top 10 errors in leak testing from our e-book - available for download free of charge on our website.