General Information On Blow Molding
There are numerous procedures that go into manufacturing various goods. Blow molding is among those and is meant to produce hollow parts using plastic materials. Generally, there are three kinds done in this process: injection stretch, injection, extrusion.
The procedure starts with plastic being melted. This is then formed into a parison or preform. The latter refers to that which applies to injection stretch and injection practices. The parison is a plastic, tube-shaped piece that has a hole at the end in which compressed air is designed to pass through. This clamps to the mold and air is then blown inside. Pressure from the air is enough to push the plastic out to fit the mold. After being cooled and hardening, the mold opens and is then ejected.
William Kopitke and Enoch Ferngren are credited as the first to have used this process. The concept behind the technique is nothing new and is based off glassblowing. The two men built a blow-molding device and in the later half of the 1930s, sold it to the Hartford Empire Company. This move would lead to the eventual popularity of the process commercially.
There was limitations in number and variety of products that led to a slower popularity. As soon as the production and variety rates improved, the amount of goods increase as a reaction. In America's soft-drink industry, plastic bottles being produced in 1977 were at zero. This number greatly increased to approximately ten billion by the year 1999. In the modern world, so many products are being made in this way and this number is expected to grow even more.
There are multiple typologies with this practice. Extrusion process, also known as EBM, involves the plastic being melted and later extruded in a tube that is hollowed out. The process might be intermittent or continuous. The kinds of products typically made with this approach: watering cans, automotive ducting, milk bottles, polyethylene hollow products, shampoo bottles and more.
IBM, or the injection process, is used for producing hollow glass and plastic goods in large quantities. With this, the polymer is injection molded on core pins, which are then rotated onto a station for inflation and cooling. This is the process that is used the least in different types. There are two main techniques associated with injection stretch practice: two stage and single.
All three kinds of this molding have disadvantages and advantages. Additionally, these are each used for the manufacture of varying products. This practice, overall, is very common today and seen in many industries.
The procedure starts with plastic being melted. This is then formed into a parison or preform. The latter refers to that which applies to injection stretch and injection practices. The parison is a plastic, tube-shaped piece that has a hole at the end in which compressed air is designed to pass through. This clamps to the mold and air is then blown inside. Pressure from the air is enough to push the plastic out to fit the mold. After being cooled and hardening, the mold opens and is then ejected.
William Kopitke and Enoch Ferngren are credited as the first to have used this process. The concept behind the technique is nothing new and is based off glassblowing. The two men built a blow-molding device and in the later half of the 1930s, sold it to the Hartford Empire Company. This move would lead to the eventual popularity of the process commercially.
There was limitations in number and variety of products that led to a slower popularity. As soon as the production and variety rates improved, the amount of goods increase as a reaction. In America's soft-drink industry, plastic bottles being produced in 1977 were at zero. This number greatly increased to approximately ten billion by the year 1999. In the modern world, so many products are being made in this way and this number is expected to grow even more.
There are multiple typologies with this practice. Extrusion process, also known as EBM, involves the plastic being melted and later extruded in a tube that is hollowed out. The process might be intermittent or continuous. The kinds of products typically made with this approach: watering cans, automotive ducting, milk bottles, polyethylene hollow products, shampoo bottles and more.
IBM, or the injection process, is used for producing hollow glass and plastic goods in large quantities. With this, the polymer is injection molded on core pins, which are then rotated onto a station for inflation and cooling. This is the process that is used the least in different types. There are two main techniques associated with injection stretch practice: two stage and single.
All three kinds of this molding have disadvantages and advantages. Additionally, these are each used for the manufacture of varying products. This practice, overall, is very common today and seen in many industries.
About the Author:
Genevive B. Mata has taught plastics molding techniques for over 15 years. He specializes in injection molding and thermoforming. If you are interested in learning more about plastic pallet crates then he recommends you visit his friends at PTM: Custom Plastics Injection Molding Company.
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