The parison is then flipped 180 degrees and reheated before air is again injected to blow the container into its final shape. The parison is created by using compressed air to form the neck finish and basic bottle shape. It also requires an IS machine, where gobs of molten glass are gravity fed into the mold. The Blow and Blow process is used to create narrow containers. Press and blow methods are typically used for manufacturing wide-mouth bottles and glass jars as their size allows the plunger into the parison. Once the parison is reheated to blowing temperature, air is injected to blow the container into shape. The parison is then transferred into the blow mold and reheated so that the parison is soft enough to finish off the dimensions of the glass. A metal plunger is used to push the gob down into the mold, where it starts to take shape and become a parison. The gob falls into the machine by force of gravity. The molten glass is cut with a shearing blade into a specific gob size. It uses an individual section (IS) machine, which is separated into varying sections to produce several containers of the same size simultaneously. The Press and Blow process is the most commonly used method in glass bottle manufacturing. To achieve the final container shape, one of two processes are used. Once the neck finish and the general glass bottle shape has been achieved, the form is known as a parison. The molded glass is created by gravity feeding gobs of molten glass into a forming machine, where pressure forms the neck and basic shape of the bottle. The weight of a gob is important to the formation process for each glass container being made. Molten glass gobs are cut by a perfectly-timed blade to ensure each gob is of equal weight before it goes into the forming machine. The type of glass this mixture will produce is known as soda-lime glass, the most popular glass for food and beverages.
The mixture is then melted at high temperatures in the furnace until it becomes a molten material, ready for formation. Silica (sand), soda ash, limestone, and cullet (furnace-ready, recycled glass) are combined into a specific mixture based on the desired properties of the bottle. All glass bottles start out as raw materials. Each process is chosen based on the kind of glass bottle being made. Creating glass containers can be accomplished by one of two different processes – the Blow and Blow, or the Press and Blow process.