Thickness change made very fast and very secure: Online strength gauging as an essential efficiency factor

On the one hand, this ensures the thickness adheres exactly to the values specified by the customer.On the other hand, it guarantees that the valuable raw material is handled economically and not even the smallest quantity is wasted. ISRA VISION overcame these challenges by designing an optical inspection solution to reliably gauge thickness online at the hot end: FLOATSCAN-Hotgauge. Based on the dual-reflection principle, the system provides results in accuracy down to thousandths of a millimeter. It measures the thickness and width of glass inline directly downstream of the float tank or directly upstream of the annealing lehr. Thanks to the exact information supplied, manufacturers always have a clear view of the material's thickness, which allows them to considerably increase their production tonnage of quality float glass. Thickness changes can now be done securely and very fast.

Color-coded display of the thickness change in float glass, measured highly precise by FLOATSCAN-Hotgauge

Identifying process errors in good time helps to save resources and costs: interpretation of a measurement via FLOATSCAN-Hotgauge

FLOATSCAN-Hotgauge can be installed either above or below the glass, working directly downstream of the float tank, at the earliest possible position during the process. As such, even the most marginal changes in thickness or width (gross and net) can be recorded within the shortest amount of time. This allows an opportunity to quickly introduce corrective measures accordingly, before there is any loss at the edges or the profile, for example. Tried and tested technology solutions are used for temperature compensated inspection: During a measuring cycle, the integrated triangulation sensor traverses along the entire glass ribbon at a speed of up to 300 mm/sec. During this time, a thickness gauging process is performed with an optical resolution within a fraction of an μm. At the same time, the reflection on the upper and lower sides of the ribbon enables the calculation of the glass thickness based on the refraction index. The measuring range is between 0.8 to 20 mm.

Clear visualisation of the thickness profile, the foundation for process optimization

Glass thickness optimization as a productivity driver

A considerable amount of potential savings and increased productivity can be found just by keeping the width and thickness of the glass ribbon in check. With the consistently high measuring accuracy of FLOATSCAN-Hotgauge, it becomes possible for production to run at the lowest tolerance limits of the glass thickness, thus optimizing the use of resources. Its integration in the hot end area directly downstream of the tin bath – where the thickness is set – makes it possible to make corrections quickly because the system provides immediate feedback. Calculations based on current user statistics demonstrate this clearly: Correcting glass thickness by an average of only 0.1mm can result in additional throughput of more than 80,000 m² flat glass each year – the system thus reaches its Return on Investment within just a few months.

FLOATSCAN-Hotgauge sensor to use at the earliest possible spot in the hot end area of the float glass production line – worldwide unique!

Focusing on user friendliness

The graphic user interface of FLOATSCAN-Hotgauge combines easy operation with state-of-the-art process visualization. Detailed statistics serve as a key factor in process optimization. Measurement data can be made available as color-coded map even in real time, allowing for fastest response times. The interface of the FLOATSCAN Quality Information System (QIS) enables the long-term storage and analysis of data.

The statistics package of FLOATSCAN-Hotgauge quickly displays which impact process changes have on the output.