A glass bottle or glass is a liquid container made exclusively out of glass, hence its name. Glass is a transparent, non-crystalline, hard yet breakable material that is made out of silica, the main constituent of sand.
Millions of glass bottles are being produced today as they are found in every household, (in multiple numbers) and are typically used to bottle water, fizzy drinks, juices, pickles and other kinds of liquids e.g cosmetics in some cases or pure alcohol.
The production of glass bottles is said to have started around 100 B.C in South-East Asia followed later by the Roman Empire around 1 A.D. The ancients up until the 1800s era used to produce glass hand blown, after melting it and forming it into a gob (the cyclinding procedure of handling the melted glass) and then shaping into a bottle using a handful of metal tools. The process was summarised as follows: the core ingredients e.g silica from sand were melted at extremely high temperatures and then clay molds were inserted into the molten liquid. The last step before packing and shipping the bottles was to ensure they were sturdy enough not to crack or break at high natural temperatures or average human touch. As the previous bottle-making steps may have put the glass bottles under internal stress, coming typically from imbalanced or sudden cooling, the manufacturers employed an annealing heat unit (oven), known as “lehr” to preserve the strength and integrity of the bottle.
The first glass bottle making machine made its first debut in the 1880s marking the beginning of the industrialization of the bottle making process. The two main automatic bottle-making procedures employed today, depending on the size and structure of the bottle are:
● The “Press and Blow” method (for Glass Jars and Bottles). This method involves getting a blob of glass (the gob), dipped into a blank form, and pressed by a plunger which inserts a dent into the blob of glass. This step forms what is known as “parison”. The parison is then turned over and inserted into a blow mold. After being blown with cool air, it starts to adapt to the shape of the mold. Usually, this method is used to make glass bottles and containers with wider openings.
● The “Blow & Blow” method. Unlike the previous method, this method is employed for making bottles with narrower openings. In this technique, a gob is initially pressed into a blank form using compressed cool air. This step shapes the neck of the bottle or its finishing outer layer. Afterwards, a second press of air is blown through the newly shaped neck, which starts to shape the bottle’s body as well. The last steps that follow to complete the bottle are the same as the “press and blow” technique.
Today, there are also one-step bottle making line machines available that make the blowing and molding procedure much more simple as opposed to doing multiple steps to complete a glass bottle. These are ideal for both small or big production units and while they cost more than traditional machines, they are actually cost-efficient for the manufacturer as they eliminate the need to purchase multiple machines for every step of bottle-making.