Shaping Plastic, a Unique 20th Century Product

Plastic has been ubiquitous in today’s markets and businesses. You see it in containers to ship products, packaging, and product components. But there is more than one to shape or mold plastic. Here are some conventional methods that are used to shape it to suit its different uses.

The Basics

Plastic is made from organic and natural materials, such as salt, natural gas, crude oil, cellulose, and coal. Crude oil is a mix of thousands of compounds, and it has to be processed before you can use crude oil. There are two main polymer families when we talk about the different types of plastics. One is thermoplastics, which will get soft when heated, then become hard when cooled. The second is thermosets, which will not get soft once they get molded.

Rotational Molding

Rotational molding is a great option if you want to create hollow objects. A plastic powder will be put into the mold prior to molding in the rotational molding process. It will be closed then put into a furnace to let the plastic powder coat the inside of your mold. The heat will melt the plastic to create one layer that will conform to the mold cavity’s shape, which creates a hollow final product. Rotational molding is often used to create products such as coolers, kayaks, and tanks.

Blow Molding

Several variations can be used for the blow molding process. For the essential process, it creates a pre-shaped length of a melted thermoplastic that is hollow, which is called a parison, and the mold will close around the parison. The force of air pressure will make hollow plastic expand into your mold shape, which will leave the inside of the item hollow. Some other versions of blow molding include stretch blow molding and extrusion blow molding. Blow molding is frequently used by manufacturers to create containers such as bottles.

Injection Molding

Injection molding is one of the most commonly used methods to manufacture plastic products. The method is used to mass-produce many items, from toys to cell phones. The process needs injection molding products to melt the resin pellets inside an injection machine that has a heated barrel. The machine will then drive your melted plastic into the metal mold. This method can limit material waste because it employs thermoplastics, which you could melt and cool several times.

Extrusion Molding

Extrusion molding involves a process that is similar to injection molding. However, a machine will press your melted plastic through a die, which gives it a fixed shape, rather than using plastic to fill a mold. The extrusion molding process is used for many products, such as seals, door frames, and pipes. However, since it can only employ thermoset plastics or multi-melt thermoplastics, it can only handle one melting cycle.

Plastic is unique to the twentieth century, and molding plastic to create certain products has been the gateway to new innovations. But these methods have also found their uses in other industries, and as many governments move to lessen the use of plastic, manufacturers are using the same methods using different materials. But it all started with plastic.

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