Glass containers are an important part of the packing process for many industries. They are a simple, cheap, and sturdy way to distribute a product to consumers. And there are a surprising variety of styles which can be used: Boston round bottles are perfect for pharmaceutical products, delicate Eros bottles are designed for perfumes, Paragon jars for holding food, and so on. What is interesting to note is that each glass container is manufactured through the same process. Many people use them, but few know how their glass bottles, jars, and jugs are actually made.

The glass container manufacturing process is actually quite simple. First, a mixture of raw materials called the batch is prepared. It is composed of sand, soda ash, limestone, feldspar, cullet, and small amounts of other chemicals and decolorizers. The batch is then brought to a glass furnace—typically an I.S. or individual section machine—where it is melted at approximately 2800 degrees. Two different methods can be used to produce glass containers on the I.S. machine: the blow and blow process and the press and blow process. They are fairly similar, and the seven major steps of the blow and blow process are as follows:

1. Gob Loading—the gob of molten glass travels into the delivery system through a funnel.

2. Settleblow—compressed air is used to shape the neck ring and bottom of the glass container.

3. Counterblow—compressed air blows the glass tight against the blank mold.

4. Transfer from the Blank Side to the Blow Mold—the neck ring reverts and opens.

5. Reheat—surface glass is reheated to a uniform temperature to prevent cracks

6. Final Blow—compressed air is used to form the final container shape

7. Takeout—the container is moved to a cooling plate and is then pushed to a conveyor belt.

The press and blow process is the same, except that the parison (partially shaped glass) is formed by pressing rather than blowing the shape. This alternative process is used on containers with finish openings large enough to allow the plunger to enter to form the internal shape of the parison.

Knowing how suppliers make their glass bottles, jars, and jugs will help you understand your product process from start to finish. Not only that, it is useful to know the packaging possibilities when dealing with reps.