Float Glass Inspection

Float Glass Inspection

Around 20% of the world’s flat glass output is inspected by a FastScan system! In the Americas, this market share now exceeds 60%.

FastScan II

FastScan II products have been specially developed to inspect float glass as it is made - at speeds of up to 25 metres/minute in ribbons up to 5 metres wide. Each system incorporates a scanner, or scanners, used in conjunction with a retro-reflective material on a patented basis, a high-speed processing module, and one or more operator interface PCs.

Each operator interface PC represents the float-glass line as a scaled "rolling map" of defects - classified and colour-coded by severity - which can be used to evaluate float-glass quality on an on-going basis.

Quality data provided by FastScan systems is used to direct cutting operations downstream - to maximise the yield of shippable glass - and to help correct production upstream to eliminate causes of persistent defects or distortions.

FastScan systems not only pinpoint tiny 0.2mm defects, they also differentiate them from dust, dirt and sulphate deposits. By inclusion of the Optical Quality (OQ) module, the FastScan system is also able to replace inaccurate and costly off-line zebra measurement, with a totally objective measure that allows for testing of 100% of the glass ribbon.

FastScan II systems are available with one, two or four scanning heads, depending on the precise quality requirement. The standard configuration for automotive float glass employs two scanners. FastScan can operate with or without washing systems, and can be interfaced to any type of cutting hardware, be it Bystronic, Reliance, Grenzebach, or even factory-specific special systems.

Two-headed systems will repeatably resolve distorting defects with cores of less than 0.2mm.

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FastScan Reflex

IAL has recently introduced a new model of its market-leading FastScan equipment - the FastScan Reflex.

The addition of a completely new channel takes advantage of a previously unexploited aspect of inspection systems - the laser light reflected from the top surface of the glass.

All existing glass inspection systems, both laser and camera based, make use of the light passing through the glass. However, some light is reflected from the top surface of the glass, and the new FastScan Reflex collects this light in a new detection channel. This channel greatly enhances FastScan's ability to detect certain types of defect - in particular, tin defects.

SPOTTING TIN DEFECTS

Top and bottom tin defects are of critical importance in many end-user glass applications. These defects consist of globules or smears of metallic tin adhering to the top or underside of the glass ribbon.

In the case of bottom tin, when viewed from above the glass these particles appear as small “mirrors”, producing a strong signal on the reflection channel. This channel therefore enables FastScan Reflex to greatly improve detection of this type of defect.

Top tin defects are also detected by virtue of their blocking of the reflected (and transmitted) light.

RED OR GREEN LASER?

FastScan normally uses red laser light to interrogate the glass ribbon. However, advances in laser technology mean that the FastScan Reflex optionally employs a solid-state green laser. The shorter wavelength of green light enables a smaller laser spot size to be produced, which leads to a significant increase in resolution.

Another advantage of the green laser is that the detection of weakly distorting or non-distorting body bubbles (a problem area for camera systems) is dramatically improved.