Nearly all forms of plastic are made from natural gas, oil, and some types of vegetation. Plastics have been demonized as a symbol of all that is wrong with society, but nearly everyone still uses them. Even the most vocal opponents express their disapproval using a plastic computer keyboard. The manufacturing method that makes these finished products possible is called thermoforming.
Even though there are environmental concerns regarding hydrocarbon pollution, the production of plastic products uses less than 3% of all the oil and natural gas burned yearly in the United States. That is still a huge number, but calling a complete halt to all production would do virtually nothing to decrease fossil fuel reliance, and would likely increase consumer costs.
The process begins by transforming refined oil into a continuous sheet of polyvinyl chloride, polypropylene, acrylic, or similar related polymers. They are fed into a production line where they are heat-treated enough to become pliable, but not completely liquid. Using one of three common methods, the plastic is forced into or over a mold, cooled, and the excess removed.
The heat is provided by radiant electrical units positioned approximately five inches from the sheet. Different polymers require specific warming periods, but once the correct temperature has been reached, they are ready to be molded into the requested shape. The most common method is called vacuum forming, which employs negative pressure similar to a home vacuum device.
Vacuum processes are limited to a relatively low maximum force, but pressure forming can achieve consistently stronger levels, and is more versatile. Before heating, the sheets are pre-stretched to eliminate thin spots over uneven surfaces. Once inserted into a mold under pressure, the air trapped inside is released, and any remaining excess can be trimmed away.
Many products require two-sided molds. The unformed plastic is heated, forced between the parts under pressure, and assumes the texture and shape of the space in between. This gives manufacturers much better control over important product details, but is costlier. Regardless of the method being used, only thermoplastics can survive reheating without breaking down.
Thicker gauges are used to make vehicle parts, medical industry accessories, electronic component housings, and are even important in some bathroom fixtures. Thinner gauges are perfect for packaging foods, cosmetic products, and numerous other small items such as screws or paper clips. While most are not biodegradable, methods of disposal and recycling are improving.
Even though there are environmental concerns regarding hydrocarbon pollution, the production of plastic products uses less than 3% of all the oil and natural gas burned yearly in the United States. That is still a huge number, but calling a complete halt to all production would do virtually nothing to decrease fossil fuel reliance, and would likely increase consumer costs.
The process begins by transforming refined oil into a continuous sheet of polyvinyl chloride, polypropylene, acrylic, or similar related polymers. They are fed into a production line where they are heat-treated enough to become pliable, but not completely liquid. Using one of three common methods, the plastic is forced into or over a mold, cooled, and the excess removed.
The heat is provided by radiant electrical units positioned approximately five inches from the sheet. Different polymers require specific warming periods, but once the correct temperature has been reached, they are ready to be molded into the requested shape. The most common method is called vacuum forming, which employs negative pressure similar to a home vacuum device.
Vacuum processes are limited to a relatively low maximum force, but pressure forming can achieve consistently stronger levels, and is more versatile. Before heating, the sheets are pre-stretched to eliminate thin spots over uneven surfaces. Once inserted into a mold under pressure, the air trapped inside is released, and any remaining excess can be trimmed away.
Many products require two-sided molds. The unformed plastic is heated, forced between the parts under pressure, and assumes the texture and shape of the space in between. This gives manufacturers much better control over important product details, but is costlier. Regardless of the method being used, only thermoplastics can survive reheating without breaking down.
Thicker gauges are used to make vehicle parts, medical industry accessories, electronic component housings, and are even important in some bathroom fixtures. Thinner gauges are perfect for packaging foods, cosmetic products, and numerous other small items such as screws or paper clips. While most are not biodegradable, methods of disposal and recycling are improving.
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 buy plastic pallets then he recommends you visit his friends at PTM: Custom Plastics Injection Molding Company.
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