Safety in road traffic primarily depends on the driver’s clear view. Windshields of curved glass may generate undesirable optical distortion effects resulting in impaired viewing. For car buyers, however, they are an important aesthetic property. Automobile manufacturers therefore impose stringent conditions on their suppliers: windshields have to meet precisely specified optical requirements and be perfect in quality.
The Chinese producer Wuhan Yaohua Safety Glass Co., Ltd. guarantees this quality level by applying innovative ISRA VISION inspection technology.
With SCREENSCAN-Faultfinder, the company has integrated a system for fully automated continuous in-line inspection of windshields into its manufacturing process. It measures the transmission optics of each glass and evaluates possible optical distortion resulting from  the bending process. The integrated analysis tools are used to identify typical defect sources, which have enabled to achieve perfect delivery quality and significantly increased the efficiency of the Wuhan production facility.
With headquarters in the province capital of Wuhan and located in the centre of the Economic and Technological Development Zone, Wuhan Yaohua Safety Glass has been a key producer of safety and automobile glass for 20 years. The company is a member of NSG-Pilkington Group and one of the top five producers of automobile glass worldwide. Its list of customers includes reputable manufacturers such as Renault, Peugeot, Citroen, Nissan ...

Safety in road traffic primarily depends on the driver’s clear view. Windshields of curved glass may generate undesirable optical distortion effects resulting in impaired viewing. For car buyers, however, they are an important aesthetic property. Automobile manufacturers therefore impose stringent conditions on their suppliers: windshields have to meet precisely specified optical requirements and be perfect in quality.
The Chinese producer Wuhan Yaohua Safety Glass Co., Ltd. guarantees this quality level by applying innovative ISRA VISION inspection technology.
With SCREENSCAN-Faultfinder, the company has integrated a system for fully automated continuous in-line inspection of windshields into its manufacturing process. It measures the transmission optics of each glass and evaluates possible optical distortion resulting from  the bending process. The integrated analysis tools are used to identify typical defect sources, which have enabled to achieve perfect delivery quality and significantly increased the efficiency of the Wuhan production facility.
With headquarters in the province capital of Wuhan and located in the centre of the Economic and Technological Development Zone, Wuhan Yaohua Safety Glass has been a key producer of safety and automobile glass for 20 years. The company is a member of NSG-Pilkington Group and one of the top five producers of automobile glass worldwide. Its list of customers includes reputable manufacturers such as Renault, Peugeot, Citroen, Nissan and Honda.
Customer requirements regarding improved product quality have led Wuhan Yaohua Safety Glass to replace manual final inspection of its windshields with an automated optical inspection solution. “On the long term, man is not capable of continually detecting and evaluating particularly tiny defects on the transparent or coated glass surfaces with reliability. We selected ISRA as our technology partner, since its systems have an excellent reputation in the industry,” states Zheng Wen, Technical Director of the Wuhan production facility, as the reason for the global player’s decision.

Patented Online-Moiré-Technology identifies defects
As a result of the production process, windshields of laminated glass vary in their optical characteristics. In order to verify their marketability, the screens of Wuhan Yaohua’s Production Line 1 pass a final inspection carried out by SCREENSCAN-Faultfinder after two manual inspections.
The ISRA system operates on a 1.25-metre-wide line which runs at a speed of 12 metres per minute.
SCREENSCAN-Faultfinder inspects the horizontal and vertical transmission optics of the screen by using  Online-Moiré-Technology developed and patented by ISRA. In this procedure, the system measures the aberration of light in the bent glass at a typical inspection angle of 30°. Distorted areas and absorbing defects such as laminated hairs or edge defects are identified 100 per cent and displayed by the software. The sensor technology is not sensitive to dust particles and fingerprints.
Equipped with up-to-date optical inspection technology, Wuhan Yaohua Safety Glass is capable of trans-lating the optical quality of screens produced into countable figures. “The application of Screenscan-Faultfinder is a relief for us,” says Zheng Wen.
“We finally have precise, objective inspection results which are quantifiable and reproducible. In addition, we save an entire process stage, since we always performed the manual final inspection procedure twice.”

Detailed defect recording reveals saving potentials
Wuhan Yaohua Safety Glass now handles the final quality inspection of its windshields rapidly and exactly in-line while bene-fiting from increased yield at the same time. The integrated, user-friendly analysis tools record measuring results and indicate the processes where defects occur. Based on this information, which is crucial for quality management, the Chinese producer can optimize production processes and increase the overall production efficiency. Zheng Wen adds: “Since we have introduced an optical inspection system, we have considerably saved resources and increased quality. This has also drastic-ally reduced the number of customer complaints.”
Efficient quality management, which only became possible due to detailed evaluation logs, has become the flagship of Wuhan Yaohua Safety Glass and is used by the company for advertising and acquiring new customers from all over the world.

Conclusion
SCREENSCAN-Fault-finder has improved the facility’s overall productivity, increased quality and reduced resource usage. The changeover to fully automated, continuous in-line inspection of windshields has consequently been an essential step for Wuhan Yaohua Safety Glass towards strengthening their market position. “We have started a trend for the future of our facility,” concludes Zheng Wen. The investment in the ISRA inspection system has quickly paid off for Wuhan Yaohua Safety Glass.