Plastic Injection Molding: The Plastic Manufacturing Process In Detail

Plastic injection molding is actually more economically friendly than a lot of other industrial processes. Consumers continue to want more products, so looking for the safest and most practical way of creating them is always an issue. Plastic injection is a process that creates a huge variety of plastic consumer products to be mass-produced and sold by plastic manufacturers all over the globe. It has been practiced for almost two centuries, and has come a long way since it's beginnings in 1868.

The first time plastic injection molding had ever been seen before was by a man named John Wesley Hyatt in the late 1860's. He had begun to make billiard balls by taking a mold of the ball and injecting celluloid in it. Celluloid was invented just a couple of decades before, and used as a fake ivory or bone. After popularity in the billiard balls rose, Hyatt manufactured a plunger type injection molding machine in order to produce more than was the case by hand.

From then on, plastic injection molding began to rapidly rise in popularity. The demand for polymer products was at an all time high, and it seemed that Hyatt's first machine could not hold up to all of the demand from consumers. Finally, in 1946, James Hendry revolutionized the machine and with it, the industry. He replaced the part of the plunger with that of an industrial-sized screw, which multiplies the speed and thus the quantity of the extrusion process.

Manufacturers have to first decide on what plastic they want their product to be made out of. For example, if a company's main output product is women's nylon stockings, then they will purchase raw nylon plastic. Other popular choices of plastic are acrylic, delrin, teflon, PVC (or polyvinyl chloride), polyamide, and polystyrene; all come in the form of small beads called resin. Plastics that are unsafe for consumption have already been ruled out and banned, so plastic companies are well aware of the safest way to buy their products!

Safety should always be a concern when it comes to manufacturing plastics, they are non-degradeable, which isn't great since we consume so much of it every day. On the bright side, awareness for recycling has increased exponentially in the last few years, and encouraging other people to recycle is always a main topic at college campuses! Thermoplastics have the ability to be heated and reheated as many times as necessary, so recycling is so important!

Once the plastic is chosen, it's time for the plastic extrusion process to really begin. First, engineers load the beads (or resin) into a device referred to as a feed hopper, which basically allows for the plastic to be gravity-fed into the rest of the machine. The hopper pours the resin into a barrel-shaped heating cylinder, which heats the plastic at temperatures up to 400 degrees Fahrenheit. As the cylinder is heating, the screw will start up, using extreme force on the melted plastic.

After the plastic is completely molten, it enters a dense array of screens for the filtering portion of the plastic injection molding machine. The screens remove the liquid plastic of any flaws or contaminants that have entered it throughout shipment or handling. It falls through screens into the final part of the machine called the die, which shapes and manipulates the plastic into the mold that it has set, depending on the final product. Molds are often made of durable and expensive steel, though some companies opt for a cheaper alloy, which is less dependable.

There is a brief cooling period so that the plastic hardens and shapes perfectly and then either the toy, window frame, or plastic molded products can cool. It doesn't take a scientist to figure out that injection molding produces a mass quantity of injection molded parts. Without the process and all of the work done by plastic extrusion companies, we'd be living very different lives!