During the assembly of a drive shaft, the snap-in of the retaining ring between the shaft and the joint must be carefully checked. The retaining ring is responsible for a positive connection in a component relevant for functional safety. A visual inspection of the assembly process is not possible because the event happens inside the component. That is why structure-borne sound analysis is applied, as the QASS technology provides a view inside the component. Moreover, this method produces extremely accurate decisions.

Animation of the snap-in process.

The QASS structure-borne sound sensor is mounted on the clamping device for the joint. This sensor captures even very low process noise and converts it into a measurement signal that the QASS measuring system Optimizer4D samples at a high frequency.

Test setup of the drive shaft featuring the QASS structure-borne sound sensor and the QASS preamplifier.

View inside the joint with a correctly snapped-in retaining ring.

This measurement signal is digitized by the Optimizer4D. The QASS measuring system transforms and processes this data in real time using the fast Fourier transform (FFT). Thereby, the measurement data is immediately available for analysis with the QASS software Analyzer4D. The data is clearly visualized in the QASS 3D spectral diagram.

Typical machine noises are cancelled out by means of a frequency mask. Process events, such as the snap-in of the retaining ring, show specific signal patterns in the 3D spectral diagram. These signal patterns can be referenced in the Analyzer4D software and stored in a pattern database. For subsequent measurements, an automated comparison algorithm calculates similarities to the observed patterns. An incorrect snap-in process reveals itself through the absence of an expected signal pattern or through significant pattern deviations which exceed pre-defined tolerance limits for the similarity assessment.

By using pattern recognition algorithms, the QASS technology can monitor any process flow and learn new process flows rapidly. Furthermore, quality defects, such as crack formation, can be detected parallel to the assembly process.

Spectral diagram of the snap-in of a retaining ring when assembling a drive shaft with a loud production machine.

Unfiltered signal of the snap-in of the retaining ring (right) and signal of the snap-in of the retaining ring after the use of a frequency mask to reduce machine noise (left).

Spectral diagram of the correct snap-in of the retaining ring after filtering.

Your Benefits at a Glance

Quality Assurance 4.0: With the Optimizer4D you can digitize your assembly process. The QASS measuring system captures and analyses process data automatically and simultaneously to the production process. Even visually inaccessible processes become tangible through the QASS technology. As a result, it is possible to detect defective components and misaligned processes objectively and as soon as they occur.

Data Integration & Big Data: The Optimizer4D can also process additional sensors and data streams from other measuring instruments via TCP/IP, USB or Profinet. For instance, the data from force-displacement monitoring can be integrated with the High-Frequency-Impulse-Measurement (HFIM) performed by QASS. It is thus possible to combine different measuring systems to meet the requirements of the age of industrial IoT.

Outstanding Analytics & Smart Decisions: The QASS technology turns big data into smart data. With the software Analyzer4D, process information can be reliably interpreted. Each QASS measuring system is delivered with pre-configured analysis programs, which can be quickly adapted to particular customer requirements when needed.

QASS as Your Technology and Engineering Partner

QASS is a manufacturer of high-end measuring systems for the analysis of industrial processes and a technology partner for the manufacturing industry. Industrial companies worldwide apply QASS measurement technology to the production of safety-relevant components with high quality requirements. Automotive companies in particular rely on QASS technology for the monitoring of manufacturing and assembly processes. As the world market leader in crack detection for straightening processes, QASS continues to set standards since 2001.

Innovative Measurement Technology

Our expertise and solution competence can be your key to a reliable and fully automated monitoring of any process that is difficult to assess with conventional measurement methods or that requires more sophisticated data analytics.

Automation and Engineering by QASS

For our customers, we develop and build solutions for the automation of production lines in combination with our measuring systems. We realize these solutions for example by means of our QOBOTs, handling systems or ejection systems.

Individual, Targeted and Competent Service

QASS stands for high standard cognitive sensor and measurement technology. Get in touch with us and together we will find the right solution for you.

Your Advantages at a Sight

Technology Expertise & Innovation Power: QASS has almost 20 years of experience in the field of sensor and measurement technology for component monitoring, quality assurance and process optimization. Innovation is a top priority at QASS and, together with our technological expertise, forms the basis for the successful realization of your project.

Solution Competence & Goal Orientation: We implement sustainable solutions for our industrial customers to increase production efficiency. To achieve this, we draw on our wide-ranging know-how in the use of QASS technology for the monitoring of various industrial processes.

Customer Orientation & Collaboration: At QASS, we consider a project only a success when we have met or exceeded the customer’s expectations with our technology. To achieve this goal, we work in close cooperation with our customers. Only through a cooperative partnership it is possible to clearly identify and fulfill customer needs.

Continuous Progress: Our R&D team constantly refines the QASS technology. Take advantage of the Optimizer4D measuring system and, together with QASS, master the leap into the future of industrial production.

QASS measuring-system Optimizer4D.


QASS structure-borne sound sensor.

Layout of the QASS structure-borne sound sensor.