Difficulties in Connector Assembly

During the assembly of an electrical connector, the snap-in of a locking hook has to be checked. As the snap process happens inside the component, its result cannot be visually inspected.

For a full quality control of the mechanical joining process, QASS’ structure-borne sound technology is applied. It captures even the faintest, barely audible process noises. As a result, the snap process can be monitored simultaneously to the process.

Schematic representation of the snap-fit during connector assembly.

Schematic representation of the snap hook locking mechanism during connector assembly.

QASS’ Structure-Borne Sound Method

The QASS structure-borne sound sensor is mounted on the clamping device for the component. It captures all acoustic signals of the joining process and converts them into a measurement signal. This signal is sampled at a very high frequency, digitized and processed in real-time by our measuring system Optimizer4D using a Fast-Fourier Transform (FFT).

Through the FFT (also known as spectral analysis) the hidden frequency information (pitches) is made visible. With this data, a process can be assessed on the basis of three-dimensional information. For the spectral analysis, we use a self-developed method, which is called ‘High-Frequency-lmpulse-Measurement’ (HFIM).

QASS' measuring system Optimizer4D with measuring chain (consisting of structure-borne sound sensor, preamplifier and sensor as well as preamplifier cable).

QASS’ measuring system Optimizer4D.

Application of Pattern Recognition

The processed measurement data is immediately available for analysis by our powerful real-time data analysis tool Analyzer4D.

Our self-developed software visualizes all data in a 3D-spectrogram and applies analysis tools such as pattern recognition and automated decision algorithms for process control.

Continuously occurring interference and machine noises can be removed from the signal by use of a spectral filter (which we call frequency mask). We recommend employing a frequency mask even when inference and machine noises are rather low, as data quality for analysis is improved through the filtering procedure.

The snap-in of the locking hook produces a clearly recognizable signal pattern in the 3D-spectrogram. It is referenced and stored in a pattern library, so that the pattern recognition algorithm can scan the incoming data for this signal pattern.

If our evaluation logic does not detect a similar pattern within process time, a NOK-signal is transmitted. In such a case, the snap connection has not been fully established.

3D spectrogram of the locking of a snap hook during connector assembly before filter application.

Spectrogram of the locking of a snap hook during connector assembly before filtering.

3D spectrogram of the locking of a snap hook during connector assembly after filter application.

Spectrogram of the locking of a snap hook during connector assembly after filtering.

Your Benefits at a Glance

100% in-line quality control through structure-borne sound

With the Optimizer4D, even visually inaccessible assembly processes that happen inside components can be reliably checked. Using structure-borne sound, QASS’ measuring system monitors assembly processes in-line and evaluates process data in real-time. As a result, defective components or misaligned process parameters can be detected as soon as they occur.

High-end complement for existing measurement technology

QASS’ measuring system can be combined with existing systems, e. g. force displacement monitoring systems. The Optimizer4D accepts additional sensors and data streams from other measuring instruments via TCP/IP, USB or Profinet. Hence, with QASS’ technology it is now possible to integrate the data for the production of tomorrow.

Powerful and customizable data analysis

With our highly developed data analysis software Analyzer4D, even large amounts of data can be precisely evaluated in real-time. The user benefits not only from three-dimensional process data but also from the multitude of individually configurable and combinable analysis tools.