Glass Bottle formation

There are two different technique for glass packaging formation - the Press-Blow and Blow-Blow process. Each process is selected according to the type of manufactured glass packaging. All glass bottles are produced by raw materials such as silica, soda ash, cullet and limestone.they are combined into certain mixtures depending on the properties of the bottle. Then, the mixture is melted at high temperature in the furnace until it becomes a molten material which is ready for forming process.

Press and Blow

Press and blow process is the most common method in glass bottle manufacturing. By a IS machine, which is divided into different sections to produce several glass bottles of the same size at the same time. The molten glass is cut into specific blocks by a shear blade. Glass block falls onto the machine under gravity. The metal plunger is used to press the block into the mold. There, it starts to take form and become a parison. Then, the parison will be moved into the blow mold and reheated to make the part soft enough to complete the glass shape. When the parison is reheated to the blowing temperature, air is injected to blow the parison into designed shape. Press and blow method is commonly used to make wide-mouth bottles and jars because their shape allows the plunger into the parison. Longwei Glass have achieved to produce small-mouth bottles and jars by upgraded facility.

Blow and Blow

Blow and blow process is used to form narrow glass packaging. It also requires IS machine. When the molten glass block falls into the mould, it will become parison by compressd air and basic bottle shape is created. The parison will be flipped 180 degrees and reheated until it is ready to be injected with air to make the final shape. For glass bottles with different neck thickness, it is best to use blow and blow method.

Process completing

After the bottles and jars have been completely formed, they will be removed from the mold and transfer to the annealing oven. The oven reheats the bottles then gradually cools them to about 390F. This process allows the glass to cool at a proper rate. That’s for eliminating internal stresses in the glass that could lead to cracking or breaking. Any bottles showing imperfections, including bubbles, cracks, or misshapen areas, are removed from the line and used as cullet. All remaining bottles are sorted according to size and type. The bottles are then packed on pallets and prepared for shipping.