There are many different processes involved with manufacturing. Blow molding is the term used to describe one of those processes in which hollow parts made of plastic are formed. Generally speaking, there are three kinds of this: extrusion, injection and injection stretch.
This practice begins with melting plastic. This is then formed into a preform or parison. The former is used for injection and injection stretch procedures. Parison refers to plastic in a tube shape that includes a hole at the end for compressed air to pass through. This is clamped to the mold and the air is blown inside. Pressure from said air is strong enough to push plastic to fit the mold. After it has cooled and hardened, the mold opens and is 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.
More than one typology is associated with the practice. EBM, or the extrusion process, relates to the plastic that is melted and then extruded in tubes that hollow it. The process might be considered continuous or intermittent. The types of goods produced through this method: automotive ducting, shampoo bottles, polyethylene hollow products, milk bottles, watering cans and more.
Injection, or IBM, is employed for production of hollow glass, as well as plastic objects in big quantities. With this process, polymer is injection molded on a core pin, which is rotated to another station to be inflated and later cooled. This is the least used process of the three different kinds. There are two different methods commonly used for the injection stretch process: single and two stage.
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.
This practice begins with melting plastic. This is then formed into a preform or parison. The former is used for injection and injection stretch procedures. Parison refers to plastic in a tube shape that includes a hole at the end for compressed air to pass through. This is clamped to the mold and the air is blown inside. Pressure from said air is strong enough to push plastic to fit the mold. After it has cooled and hardened, the mold opens and is 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.
More than one typology is associated with the practice. EBM, or the extrusion process, relates to the plastic that is melted and then extruded in tubes that hollow it. The process might be considered continuous or intermittent. The types of goods produced through this method: automotive ducting, shampoo bottles, polyethylene hollow products, milk bottles, watering cans and more.
Injection, or IBM, is employed for production of hollow glass, as well as plastic objects in big quantities. With this process, polymer is injection molded on a core pin, which is rotated to another station to be inflated and later cooled. This is the least used process of the three different kinds. There are two different methods commonly used for the injection stretch process: single and two stage.
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:
Henry A. Parker has taught plastics molding techniques for over 15 years. He specializes in injection molding and thermoforming. If you are interested in learning more about premium plastic solutions then he recommends you visit his friends at PTM: Custom Plastics Injection Molding Company.
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