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1 Mar 2014

Thermoforming 101 Infographic

Thermoforming 101: From Turtle Shells to Clamshells from plasticingenuity

Thermoforming is the process that turns raw plastics into the packages and containers people rely on every day. While the process has changed shape over the years, it was seen in its earliest incarnations thousands of years ago. So what is thermoforming, exactly, and how is it different now from when it was first invented? Thermoforming is the process of heating a plastic sheet and stretching it over a mold. As the plastic cools, it hardens, permanently retaining that shape. Ancient Romans were some of the first thermoformers in history. They imported turtle shells from the East, which they soaked in hot oil or water. This made the keratin in the shell pliable enough for them to form tools like bowls and eating utensils. Fortunately for the turtle population, thermoformers today rely on artificial alternatives. In the 1860s, the inventor John Wesley Hyatt invented celluloid, along with the process of heating and stretching it over a mold. Before long, the process was being used to make everything from piano keys to ping pong balls. During World War II, the military used thermoforming to produce heavy duty, cost-effective supplies like machine gun turrets and relief maps. Today, thermoforming is a distinctly fast and versatile method of creating plastic packaging, and is used to make packages for everything from cell phones and pharmaceuticals to food products. First, thermoformers carefully draft designs and construct prototype molds for packages. Next, the plastic sheet is stretched out over the mold and heated until it becomes soft and pliable. The softened plastic adheres to the mold and takes its shape. Sometimes, a vacuum inside the mold holds the plastic in place, keeping it pressed tightly to the mold. This is common for complex designs. Other types of thermoforming may use air pressure or even a second mold to hold the plastic in place. After the plastic cools and hardens, it is cut into pieces—a single sheet can yield a large number of packages, which must be separated after they're formed. Its speed and cost-effectiveness make it one of the most popular methods for processing plastic packaging today. A variety of plastics lend themselves well to thermoforming, including: These aren't all of them, but they're the most common. It all depends on what the individual thermoformer is used to working with—not including turtles, of course! 

SOURCES: Plastics Historical Society, Mayfield, Sinotech, Plastic Ingenuity