Plastics Processing
The plastics industry represents one of the major manufacturing segments. There are two main families of plastics:
- Thermosetting
- Thermoplastic
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Typical plastic processing operations include:
- Extrusion
- Blow Molding
- Injection Molding
- Thermoforming
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Thermosetting Process – These products are formed into a permanent shape by heat and pressure and may not be altered after curing. This process is more expensive and can be more difficult than others because thermoset materials cannot be remelted once they have been melted and formed for the first time. Thermoset products are the choice when the product is used in an application where heat exists such as plastic parts found on or near the engine of a car. The most common production process is casting.
Thermoplastic Process – Plastic material may be heated and formed by pressure. Upon reheating, the shape can be changed. Most plastic products are made with this process because they are easier to mold into various shapes. These products cannot be used where heat might exist.
Typical plastic processing operations include:
1. Extrusion Process– used to make continuous shapes such as moldings, tubing, bars, water hose, weather stripping, and any part that has a constant shape. This process creates the desired continuous shape by forcing molten plastic through a metal die.
2. Blow Molding Process – used in the production of hollow products such as bottles and containers. The molten plastic enters
around a tube that also forces air inside the material, which forces it against the interior surface of the mold to create the shape desired.
3. Injection Molding – is the most commonly used process for creating thermoplastic products. The process involves injecting molten plastic material into a mold that is in the form of the desired shape. Injection molding is used to create products such as housings for electronic implements, automotive interior components, food storage containers, and components for medical applications.
Thermoforming of Plastic Process – is used to make all types of thin-walled products, such as containers, guards, fenders, food packages, and cosmetic packaging. The process works by taking a sheet of plastic material and heating it until it softens. Vacuum pressure is then applied to suck the hot material down against the mold to conform to the desired shape.