General Information On Blow Molding

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.

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 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.

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.

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.

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 plastic pallets for sale then he recommends you visit his friends at PTM: Custom Plastics Injection Molding Company.