Most of the products we use today, particularly components of large products, are made using a process called injection molding. It requires the use of mold cavities into which materials in molten state are poured and solidified to form anything from ice trays and chairs to bottle caps and bins.
Injection molding uses a variety of materials such as glass, metal and thermoplastics. We'll be looking at the last and how it scores over others in terms of cost and recyclability.
Plastic, as we know, is a low cost alternative to expensive metals and glass. It's durable, rust-free and surprisingly tough considering its low density. Thermoplastic, in particular, allows manufacturers to produce very complex shapes at a much lower cost than other materials. It's pliable which means it can take on almost any shape but hardens when cooled. Additives are added to reduce brittleness when plastic is exposed to very cold temperatures. Further, finished products can be reheated to form other shapes.
Imagine a world where all plastic products have to be created by hand. Needless to say, we'd be left with misshapen and structurally weak objects that wouldn't last a day. With injection molding, precision is achieved and structural soundness maintained. Here's a look at the other benefits of this invaluable process.
Using molds reduces the generation of scrap as the cavities are shaped to contain only what amount of plastic is needed. This translates into money saved and less problems with waste management.
Waste plastic can be reused to form other important parts and components. This waste is equivalent in quality to virgin plastic. Waste is, therefore, again minimized.
The labor cost of using injection molding processes is far lower than what it would cost to mold plastic by hand. There's high productivity and the time taken to manufacture products is drastically cut down.
Injection molded plastics have little to no defects. If defects occur, the fault rarely lies with the mold cavities. Note: Common defects include burrs, an uneven layer; blisters, where raised bits produce a rough and uneven surface; and voids, empty spaces on the surface. Defected products are remade.
Despite the bad rap plastic gets for being non-biodegradable, it's highly recyclable and plants often use discarded and unused plastic parts.
Finishing time is reduced with injection molding as the process already takes care of most of the work. Labor cost and time is further reduced.
Where metal and glass cannot be used in certain applications, plastic injection molded products are often the only solution. Industries like automotive, oil, gas and electronics (electrostatic discharge is minimized) use them on a regular basis.
Injection molding machines are generally fully automated. Operators, therefore, don't have to be involved in risky manufacturing processes.
Molds are typically designed using computer aided manufacturing and computer aided design. This leaves very less room for error so products requiring to be made in certain precise shapes can be produced.
The speed with which injection molded products can be manufactured allows large volumes to be produced in a short time. Smaller quantities of commercial items can also be shipped online at an affordable cost. If customization is required, some manufacturers invite designs from customers by having them send in plans via email or directly uploading them to their websites.
