In Line Inspection of Windshields

Marc Rosenbaum, Micro-Epsilon France

Measurement of 3D shape of windscreens have always been a challenge. Measurement of surface aspect defects, so important to master correct wiping and cleaning of rain and projections is an additional task difficult to perform.

Adding to the picture the necessity to identify and eliminate parts with internal defects such as stones, bubbles and lenses, inspection to perform becomes barely very tricky and unreliable.
Design and technical evolution of windscreens making them larger, rounder, and more curved, added to the introduction of flat wipers renders the need of a thorough 100% in line production inspection all the more necessary.

The use of deflectometry linked to reflectometry and measurement in transmission by a recently introduced ReflexCONTROL overcomes all these issues. It uses the same principles as visual inspection but offers a quantitative, traceable, fast and accurate way to measure in-line all geometrical characteristics and defects of a windscreen: 3D shape, Curvature, Waviness, local surface defects and inclusions including optical defects in transmission. Measurement is done without contact, over the complete glass plate surface, very fast (a matter of seconds) and very accurately (defects identified are below 0.3 mm size) in a very simple and flexible set up rendering ReflexCONTROL the ideal product for 100 % in line inspection.

The paper refers to previous works of Professor Yves Surrel, Institut National de Métrologie, BNM-INM/CNAM. Deflectometry measurement examples are drawn from measurement tests implemented by Techlab.

Full-Text Article [987 KB]

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