Chinese glass producer Wuhan Changli has improved quality control on its production lines by installing an automated inspection system. The company manufactures more than 12 million square metres of low emissive glass per year. Production lines can reach speeds of 50 metres per minute.
The inspection systems from Isra Vision – the P2-Color and P2-Coating – provide quality engineers with reports giving the type and size of a defect. The engineers can use the data to reject non-optimal products or stack them separately.
Scratches, arcing, water marks, glue and debris were among the first defects detected and classified with the systems.
Before installing an automated process, workers inspected the glass manually at the end of the production line. However, reoccurring defects resulted in material losses for Wuhan Changli, and imperfections like glue stains and debris kept happening repeatedly.
‘With the Isra systems, the quality of our entire production chain improved very quickly. They mean an important advantage in monitoring the results and corresponding processes, as well as increased convenience in quality control,’ commented Wang Gui Rong, responsible for the project with Isra at Wuhan Changli.
The two P2 systems are designed to detect all types of coatings defects on Wuhan Changli’s Low-E glass products. Besides detecting small defects, they can monitor the colour homogeneity of the full surface, which is a big advantage over spectrometer-based systems measuring coating colour.
The P2 systems include a dedicated server PC with high capacity data storage to document and monitor defects and respective trends over the long term.
The P2 systems are enhancing the quality staff’s judgement, reducing false detections, and are linking the quality and production departments more closely, enabling fast reaction to events on the line. Through better production monitoring, processes are optimised and throughput has improved, leading to an overall yield improvement.
Glass half full - Greg Blackman on the intricacies of the lighting and camera systems required for high-speed glass inspection