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There's no doubt that life would be very different if it weren't for the various contributions to plastic injection molding. I mean, think about the number of things in your house that would be impossible without the process! Everything from your child's toys to the window frames around your house have gone through custom plastic extrusion. It has become a process that we have thus far relied on heavily, and one might say that it is now permanent to our way of life, at least until something new comes along. At the current rate that plastic injection molding is going though, it just doesn't seem like there can be much competition in the field. Several decades of work and research have been dedicated to the field of plastic injection molding, and with excellent results, as is clear by the number of products manufactures produce and consumers consume. But where did this process come from, and how does it work?

Throughout the course of industrialization, there has been a lot of pressure on the reduction of industrial waste. This is because many industrial processes can be harmful to the environment, but plastic injection molding is actually one of the safest! Since plastic injection is used in such frequency, it's a good thing that it isn't highly dangerous to the environment, otherwise we'd have to look for new ways to produce so many things. Thankfully, plastic injection has been fine-tuned to perfection ever since its debut in 1868.

John Wesley Hyatt came up with the idea when he began to ask himself how to make a full set of billiard balls easier than he had previously. He began to inject a material by the name of celluloid into spherical molds that he cast, and thus injection molding was born. Celluloid was discovered several years prior to Hyatt's use of it, and was sometimes used to mimic bone or ivory in products. Soon, Hyatt's business expanded, and he felt that his process should too, so he created the very first injection molding machine, which was run by a plunger mechanism.

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!

Making sure that plastic is safe and environmentally friendly is important to consumers and producers alike. So how do we deal with the problem that plastic isn't biodegradable? It's as simple as recycling, most plastics can go through the plastic intrusion molding process as many times as necessary. Recycling is cheaper and easier for everybody involved, including the environment!

Now, the plastic beads, or the resin, which is essentially raw plastic, is poured into what's called a feed hopper. This is a part of the injection molding machine, and it tilts the resin upwards and gravity-feeds it into a heating cylinder, shaped much like a barrel. The resin begins to fill through an opening in the heating cylinder, where it runs into the aforementioned large industrial screw, which begins to twist and turn the plastic. Simultaneously as this is happening, the heating cylinder begins to get extremely hot, melting the plastic entirely.

Then, the plastic goes through a filtering device to rid it of any contaminants it may have collected. By doing this companies eliminate the risk of ragged edges, or plastic products that simply aren't uniform. Finally the plastic enters a die, whose primary purpose is to form the mold into the shape of the final product. Molds can be made of expensive steel, but this proves to be much more durable, if a company is watching its expenditures they can opt for the less durable aluminum or beryllium-alloy metal.