A lot of different practices are involved when it comes to manufacturing goods. Blow molding is one of the many and is designed to make hollow parts from plastic. In general, the three types: injection, extrusion, injection stretch.
The process starts with the melting of plastic. Then it is formed in a parison or preform, which is used for injection stretch and injection procedures. The parison is a piece of plastic shaped like a tube that has a hole at one end in which the compressed air is able to pass through. This is then clamped to a mold and air is blown inside of it. The pressure from the air is enough to push the plastic out to match with the mold. Once it has cooled and hardened, the mold will open and the part can be ejected.
The first people verified to have used this process are William Kopitke and Enoch Ferngren. The concept of this technique is based on that of glassblowing. Kopitke and Ferngren created a blow-molding machine and in 1938, sold it to Hartford Empire Company. This is what launched the commercial-level of this process.
Because of the limitations of number and variety in products, this practice did not become more popular until later. Once the production rates and variety increased, so did the number of goods created. In the US soft-drink industry, the amount of plastic bottles made went from zero during the late 1970s to approximately ten billion in 1999. Nowadays, even more of these products are blown and the number is only expected to increase more.
There are different typologies when it comes to this practice. EBM, or the extrusion process, involves plastic being melted and then extruded into a hollow tube. These processes might be continuous or intermittent. Types of products made from this practice: milk bottles, automotive ducting, shampoo bottles, watering cans, polyethylene hollow products 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.
There are disadvantages and advantages associated with the three different types of molding. Likewise, these are employed for the manufacturing of different parts. The practice, as a whole, has become more common and is employed in numerous industries of today.
The process starts with the melting of plastic. Then it is formed in a parison or preform, which is used for injection stretch and injection procedures. The parison is a piece of plastic shaped like a tube that has a hole at one end in which the compressed air is able to pass through. This is then clamped to a mold and air is blown inside of it. The pressure from the air is enough to push the plastic out to match with the mold. Once it has cooled and hardened, the mold will open and the part can be ejected.
The first people verified to have used this process are William Kopitke and Enoch Ferngren. The concept of this technique is based on that of glassblowing. Kopitke and Ferngren created a blow-molding machine and in 1938, sold it to Hartford Empire Company. This is what launched the commercial-level of this process.
Because of the limitations of number and variety in products, this practice did not become more popular until later. Once the production rates and variety increased, so did the number of goods created. In the US soft-drink industry, the amount of plastic bottles made went from zero during the late 1970s to approximately ten billion in 1999. Nowadays, even more of these products are blown and the number is only expected to increase more.
There are different typologies when it comes to this practice. EBM, or the extrusion process, involves plastic being melted and then extruded into a hollow tube. These processes might be continuous or intermittent. Types of products made from this practice: milk bottles, automotive ducting, shampoo bottles, watering cans, polyethylene hollow products 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.
There are disadvantages and advantages associated with the three different types of molding. Likewise, these are employed for the manufacturing of different parts. The practice, as a whole, has become more common and is employed in numerous industries of today.
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 injection molding services then he recommends you visit his friends at PTM: Plastic Injection Molding Services.
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