How Glass Bottles Are Made

The most straightforward and simple answer to our title is; that the Blow and Blow process or the Press and Blow process can be used to make glass containers. The type of glass bottle is taken into consideration when selecting a process.

All glass bottles begin their lives as unprocessed components. The desired properties of the bottle are taken into consideration when a specific mixture of silica (sand), limestone, soda ash, and cullet (furnace-ready, recycled glass) is created.

The mixture is then heated to a molten state in a furnace before being used in the manufacturing process. Soda-lime glass, the most common type of glass used for food and drink, is the result of this mixture.

In light of what we’ve learned so far, we’ll take a closer look at how glass bottles are manufactured today. Nevertheless, before we get too far into the process, we need to familiarize ourselves with a few terms related to glass. The following terms are frequently heard in the jar and container manufacturing industry:

Glassmaking Termologization

Glass Vocabulary 101 begins with the word gob. The word ‘gob’ here does not refer to a Gobstopper. A gob like this one has nothing in common with Willy Wonka’s chocolate factory. A gob is a cylinder of melted glass in the art of glassmaking. A shearing blade is used to cut and shape the glass into a gob when the temperature is right. Imagining this as something that looks like a gob of glass is a good analogy.

The word parison is up next on our vocabulary list. The term “parson person” or “Parisian” should not be used interchangeably. A parison is a piece of molten glass that has yet to solidify. Glass jars and bottles can be made from a gob halfway through the process.

The Actual Formation Of Glass Bottles

Before they enter the forming machine, molten glass gobs are weighed and then cut with a precisely timed blade. Each glass container’s formation relies heavily on the gob’s weight. The shaped glass is made by letting gobs of molten glass fall into a making machine, where pressure gives the bottle its neck and basic shape. 

A parison is formed once the neck is finished and the general shape of the glass milk bottle

has been achieved. The final shape of the container can be achieved using one of two methods.

1. Blow-And-Press Process

Glass bottles are made using the Press and Blow process, which is the most common method. Several containers of the same size can be made at the same time by using an individual section (IS) machine, which is divided into different sections. 

Using a shearing blade, molten glass is shaped to a precise gob size. Gravity pulls the gob into the machine. Pushing the gob into the mold with a metal plunger causes it to form into a parison. It is then reheated so that the parison softens and can be used to complete the glass’s dimensions. 

Air is pumped into the parison once it reaches a temperature where it can be blown into shape. Wide-mouth bottles and jars, whose size allows the plunger to enter the parison, are typically made using press and blow methods.

1. Blow-By-Blow Method

Narrow containers are made using the Blow and Blow method. Gravity-fed molten glass feeds into the mold via an IS machine. Compressed air is used to form the bottle’s neck finish and basic shape. 

Afterward, the parison is flipped over and reheated so that the container can be blown into its final shape. To reshape the bottle, we’ll use compressed air this time. When it comes to making glass bottles with varying neck thicknesses, the Blow and Blow method is the most effective.

Completing The Task

The bottle is removed from the mold and placed in the annealing lehr once it is finished being formed. To cool them to 390 degrees Fahrenheit, the lehr slowly reheats the bottles to a temperature of approximately 1,050 degrees Fahrenheit. This technique allows the glass to cool evenly, reducing the risk of it cracking or shattering due to internal stresses.

Inspecting the Work

Once the bottles have been thoroughly inspected, the quality control process begins. Imperfections such as bubbles, cracks, or misshapen areas are culled from the production line and repurposed as new bottles. Sorted by size and type, the remaining bottles are now ready to be sold in luxury retail packaging. Pallets containing the bottles are then constructed and shipped.

Cullet is what happens to glass bottles and jars that don’t make it through inspection. A food and beverage manufacturer fills the containers and seals them with a capping machine similar to the tin capping machine, and then distributes them to grocery stores, restaurants, hotels, and other retail locations for customers and shoppers to enjoy.

Conclusion

Glass can be recycled indefinitely, and a repurposed glass container can go from the recycling bin to the retail shelf in as little as 30 days. There is no end to the glass manufacturing cycle, and so the story goes on.