New automatic inspection system brings light into fiber composites

WebControl SP checks cut-to-size fiber composite webs with unprecedented accuracy and speed.

With twelve cameras, modular high-capacity LEDs and sophisticated algorithms, the system checks the surface and dimensions in just one measurement. WebControl SP detects the smallest of defects even in dark, inhomogeneous material, such as carbon fibers. The automatic inspection system also performs all handling of the test pieces during inspection – including feeding, transport and discharge of the tested items.

Whether for seat shells or pedal sets – innovative fiber composite materials have been gaining much ground in automotive engineering recently. They combine the advantage of increased stability with that of significant savings on weight. The safety requirements on such materials are extremely high. A perfect inspection task for Pixargus, the market leader in quality control systems for composite materials and carbon fibers.

WebControl SP, the new automatic testing system developed by Pixargus, performs two quality checks at the same time. With µm accuracy, it checks the actual contour of every test piece against its 2D nominal contour and the surface for critical structures such as improper fiber orientation or defects such as fissures, scratches, holes, weaving or loop defects. Even dark and inhomogeneous material does not affect the accuracy of measurement. The system performs this double task using two different lighting methods in one measurement: incident light from above for inspecting the fibrous surface and transmitting light for the contour check.

“We have set up a high-performance light scenery with very tight measuring tolerances of +/-50 µm. This delivers extremely strong contrasts and optimal camera images,” Jürgen Philipps, Managing Director of Pixargus, explains the new technology. “The LEDs and our camera sensors are arranged and harmonized in a most effective way. This, in combination with our sophisticated, high-performance algorithms, ensures that there will be no disturbing effects resulting from any critical material properties of the inspected items ... and, what is more, in a fully automatic inspection process with a high testing rate - proof of measuring system capability included!”

“This results in a so far unattained quality of process stability and process repeatability as required by the automotive industry,” explains Dirk Broichhausen, Director Sales & Marketing. The multi-camera sensors of WebControl SP provide high-performance surface inspection. Per camera, as many fields of view as desired can be set in order to perform various different inspection tasks at the same time. The system verifies all quality-based decisions by congruency checks of the measured data. “We don’t simply state: ‘The fiber orientation is correct and the contour is as it should be’. We don’t look at these quality aspects separately but relate them to get a comprehensive picture of the quality,” adds Broichhausen.

Automated handling for stable quality processes with high throughputs
After removing the die-cut webs from the manually filled magazine, WebControl SP performs all subsequent handling fully automatically. The system can handle pieces of up to 700 mm x 700 mm at a daily capacity of up to 10,000 items. The test pieces are transported by air cushion technology. The processed quality data can be integrated into downstream processes and Industry 4.0 applications.

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The translucent measuring table of WebControl SP is equipped with high-performance LEDs. Perfectly harmonized LED and camera sensor technology and sophisticated, high-performance algorithms ensure measuring results of unparalleled precision.