How It’s Made?
Step 1: Batch Mixing
It begins with the earth’s abundant raw materials: sand. Glass itself is also an ingredient. Its recycling reduces the need for raw materials and accelerates the melting process. Next, the silica sand, soda ash, limestone, and other raw materials mix in proportion and sending into a furnace. The raw material will be heated at about 1500℃ in the furnace to become liquid and merges. Then, it’s ready to leave the melting furnace and enter a bath of molten tin.
Step 2: Molten Tin Float Bath
The glass comes out from the furnace, flows gently and spreads out, looks like honey, and becomes a flat continuous ribbon in the tin bath. As we know, tin is a low melting point metal; its molten liquid level is flat and smooth. As a result, it makes glass a good flatness and no water ripples. In addition, there’re top rolls to act on the spread surface of the glass, control the glass speed and thickness.
Step 3: Annealing Lehr
At the end of the float bath, the glass is cooled down further and leaves the tin bath at 600℃, when it is just solid enough to climb on metallic rollers and be driven inside the lehr. In the lehr area, the glass is annealed and gradually cooled to relieve inner stresses and prevents splitting in the cutting phase: cool down too quickly, it would break.
Step 4: Inspection& Cutting
After the cooling, high-performance scanners detect all kinds of defects and identify imperfections to be discarded. When the glass passes the quality inspection, it will be cut into desired dimensions and packed depends on specific customer requirements.