PROCESS DRYING SYSTEM ELIMINATES FALSE DEFECT DETECTION AT PILKINGTON WINDSCREEN PLANT

When car windscreen maker Pilkington UK Ltd found that a new laser-based defect detection system was compromised by water droplets remaining after cleaning, they called in process dying specialist Secomak to solve the problem.

Pilkington produces windscreens for all the major car makers including Ford, Jaguar and Rover. To maximize quality the company installed a high performance laser defect detection system capable of picking out small pit marks or cracks in the glass. However, unless glass is perfectly dry the laser will signal water droplets as a defect. False detection of defects is costly and time consuming.

Secomak designed a drying system, based on its air cannons, that has been added to the King’s Norton production line between the wash and final inspection stages. The machine incorporates a reception and exit conveyor and the drying cycle time is just 18 seconds.

The air cannons deliver powerful currents of air both above and below the convex screens and track up and down to follow the screen contour as it passes on a conveyor. To further improve the drying, the cannons oscillate from side to side as the screen passes. Pilkington considered, and rejected, the use of standard air knives because they could not follow the glass curvature effectively.

The choice of a Secomak system was also prompted by the company’s ability to offer a complete solution including transfer mechanisms, fans, air cannons, and system installation and commissioning.