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 polymer 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?
In any industrial process, the environment needs to come into play as far as wasteful and harmful material. Thankfully, plastic injection molding is actually a very safe way to create useful and environmentally friendly plastic products in mass quantity! Plastic injection molding consists of the melting of different types of thermoplastics and thermosetting plastics. It is such a completely complex process that takes actually only a few minutes, I can’t believe I had never heard about it until now!
Injection molding was invented by John Wesley Hyatt in 1868; this was the first time the process had ever been seen before. He began to make billiard balls by injecting a material called celluloid into sphere-shaped molds. Celluloid was invented in the 1820’s, and was most often used because it looked similar to ivory or bone. Soon after his first steps into plastic injection molding, Hyatt looked to make the process easier on himself, so he created the very first injection molding machine (which employed the use of a plunger-type piece).
From then on, plastic injection molding began to rapidly rise in popularity. The demand for plastic molded 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.
The first thing for a manufacturer to consider when beginning the plastic injection molding process is the type of plastic that they want to be creating their products from. There are quite a few variations of plastic that are too unsafe, and plastic companies make it their duty to produce safe goods for their customers. That’s why it’s important to use the right kind, usable plastics consists of polyvinyl chloride (also referred to as PVC, often used for piping), acrylic, teflon, delrin, and polystyrene; which all come as raw beads referred to as resin.
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!
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 this, the molten liquid plastic passes through a complex series of thin screens, which are meant to catch any flaws or contaminants in the molten resin. These screens are held together by a puck-like piece of metal with holes drilled into it. The molten plastic is pushed out through these holes and into the final part of the machine called the die. The die is responsible for giving the plastic its shape, whether it be a knob or a window frame!
After the product cools, it is ready to be packaged and shipped out as plastic molded products or toys. Quality extrusion services only takes a few minutes to complete. It is incredible how fast a polymer company can make these products and how helpful they are!
– Gregory Scott