1．The standards are strict

China has not issued a standard specifically for toughened U-shaped glass. To obtain CCC certification, it must comply with the national standard Safety Glass for Use in Buildings: Toughened Glass. Because the test methods primarily address flat glass, U-shaped glass must follow the full flat-glass test procedure. Meeting requirements for fixing methods, test fixtures, and calibration of special measuring tools presents a significant challenge.

2. Both sides

The main challenge in tempering U-shaped glass is meeting both safety and dimensional requirements. Safety performance is assessed through impact resistance, fragmentation, and shot-bag impact tests. One particularly demanding impact test requires the glass to remain intact when struck by a 1040 g steel ball dropped from 1000 mm. Meeting the strength requirement requires thorough heating and rapid cooling. However, excessive heating can soften and deform the glass, while excessive cooling can distort its flanges. High-quality toughened U-shaped glass therefore requires a balanced process.         

3．Equipment capacity

There are almost no furnaces designed specifically for tempering U-shaped glass, either in China or worldwide. Most U-shaped glass on the market is tempered in small furnaces whose stability and capacity make it difficult to produce compliant glass. Appleton uses a large U-shaped glass tempering furnace with heating and cooling capacity well above the process requirements. The highly automated production line strictly controls each key process parameter and continuously monitors small process changes to maintain consistent finished-product quality.

4 Production experience

Control of U-shaped glass production and sufficient experience in flat-glass tempering are essential prerequisites for tempering U-shaped glass. Few manufacturers have both capabilities. Appleton produces rolled glass and toughened glass and has mastered the full process, from raw-material mixing and rolling to annealing, edge grinding and tempering. Its work is supported by established theory and ongoing training and support from Pilkington in the United Kingdom. Years of continuous production have helped Appleton develop skilled staff and accumulate valuable experience.

5. High standards: the ASG standard

National and industry standards have different requirements, so products on the market can meet at most one or two of them simultaneously. To produce high-quality U-shaped glass, Appleton has implemented strict internal standards. Its finished products can also meet the relevant domestic standards for U-shaped glass.