Smart end-of-line tests - Acoustic and Vibration Measurements

Incentive

Ever-growing customer demands regarding comfort and quality in the automotive sector do not stop at acoustics requirements. Besides stricter acoustic limits, an increasing number of OEMs are calling for longer inspection intervals for the party they supply. This makes more elaborate and extensive quality controls indispensable.

Approach

The quality of components can already be assessed during or at the end of the production process by means of acoustic and, in particular, vibration measurements. But: What criteria determine whether a component is in order or defective? Where does a sensor have to be positioned? Which values are still acceptable? And: Does the selection process sometimes class parts as being not in order that would generate acceptable noise levels in the vehicle?

Solution

These complex questions can be answered by comparing the “acoustic fingerprint” of a part in the production process with that in the vehicle - as perceived by the user later on. This is measured on an end-of-line (EOL) test bench. But what sounds simple at first is often a lot more difficult when it comes to the details: In most cases, a spectrum-based approach is necessary to evaluate a correlation between the two systems. Compared to averaging the data in the time domain or an unfiltered single value in the frequency domain, this is usually more time-consuming and may call for additional testing equipment. The reward, however, is usually lower reject rates and products with guaranteed high quality.

Our services

We will gladly assist you with optimizing the acoustic and vibration design and setup of your existing EOL test bench or help you to develop a completely new one. We can also help you adapt your test benches in line with the requirements of the complete vehicle or your OEM’s parts test bench. The Fraunhofer Institute for Building Physics IBP has a wealth of expertise and a wide range of acoustic measurement systems and test equipment at its disposal for such tasks.