During the past century, plastics have revolutionized the way we live. Today, plastics are found in a huge array of products, including food packaging, electronics, cars, medical equipment, and clothing. Plastics generally are lightweight, resistant to chemicals, good insulators for thermal and electrical components, and economical, making them a popular choice of material for many applications. In addition, the properties of a plastic can be manipulated to meet the requirements of a specific use. As a result, plastics technologies and applications are ever-expanding, and the industry continues to develop and provide job opportunities.

While a variety of processing methods exist to shape plastic material into a finished product, the five most common are thermoforming, extrusion, injection molding, blow molding, and rotational molding. In the process of thermoforming, a thin sheet of plastic is softened by heating and then placed over a mold. Most of the air between the plastic and the mold is removed, pulling or “forming” the softened plastic into the shape of the mold. This process is used to make products such as take-out food containers and to create prototypes and craft projects, like the car bodies seen in the video.

The process of extrusion melts plastic material in a heated and highly pressurized chamber and then forces the molten plastic through an opening, called a die, to form the desired shape. After the plastic exits the die, it is cooled along a conveyor belt. Extrusion is used to make products such as continuous plastic sheets and pipes, plastic wrap, bags, cables, and vinyl window trim.

The process of injection molding also begins by melting plastic material in a heated chamber. The molten plastic is then forced out of the chamber and into a closed mold. The high pressure under which the plastic is injected into the mold ensures that the cavity is completely filled. After the plastic has cooled, the mold is opened and the molded product is removed. Injection molding is used to make a wide variety of products, including yogurt cups, toys, and cell phone cases.

The process of blow molding is used to make hollow products. Extrusion blow molding forms a tube of heated plastic material, which is then surrounded by a mold. Compressed air blown into the tube expands the tube to form the shape of the interior of the mold. Another method of blow molding uses a preform—an object that has been previously shaped by injection molding. The preform is heated and then the softened plastic is blown and pressed against a mold cavity into its final shape. Products such as milk jugs and soda bottles are formed by blow molding.

The process of rotational molding is used to make hollow products that are relatively large in size. Plastic material is placed inside a mold that is mounted on a machine that rotates on two axes. After the plastic is heated, the force of the rotation distributes the molten plastic, coating the inside of the mold. This process is used to make items such as storage tanks, garbage cans, and kayaks.

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