Optical quality control in the pre-processing of tempered glass

Mr. Kai Vogel, Viprotron GmbH

The current manufacturing of tempered glass is a complex as well as time- and cost-intensive process. Not only long processing times, but also high energy costs have a significant impact. Additionally, there are often capacity bottlenecks at the tempered glass – as well as at the heat soak furnace. Glass defects and contamination will mean that a high-quality finished product cannot be delivered. Such defects must be avoided at all costs at the beginning of the value creation chain. Some companies try to minimize this problem by using manual inspection at the entrance to the furnace. However, this method is unreliable, since the staff doing the inspection also have to load or unload glass and may not have the right lighting. Furthermore, horizontal glass surfaces are always difficult to examine and when inspections are carried out manually, there is the common problem of limited reliability due to fatigue or low motivation of the staff performing the inspection. An examination location such as this also has the dis-advantage that a glass that has been removed due to defects cannot be replaced immediately, leading to the furnace not being used to full capacity – and, in the worst case scenario, to customers not receiving deliveries on time. A state of the art vision system is today able to cut quality relevant losings with convincing results and even allows the reallocation of human inspectors for other assignments.

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