In today’s manufacturing environment, plastics are being used to make everything from human body parts to automotive body parts. Starting in the 1940s, when high demand existed for mass-produced products that were inexpensive to manufacture, injection molding began to grow. In 1946, at the end of the war, the invention of the first screw-type injection machine improved the quality of the products being made. Molds were being made for any variety of applications and what was once used to make combs and buttons was now being used to produce a wide range of items for many industries including:
- Plumbing
- Consumer products
- Toys
- Aerospace
- Automotive
- Construction
- Medical
- Packaging
The raw materials used in the plastic injection molding process include thermoplastics, thermosets and elastomers. These are also called polymers and resins and there are more than 20,000 unique formulations that can be injected into molds to produce parts with specific properties to be utilized for specific purposes.
Now-a-days injection molding machines are fairly simple and straightforward. They consist of hopper where a raw material is placed, a heating cylinder and an injection plunger. Molds are typically made from steel or aluminum. Major advantages to using plastic injection molding for the manufacture of parts include:
- Low labor costs
- Minimal scrap loss
- Ability to complete high production rates
- Repeatability of high tolerances
- Little need for finishing
- Wide range of materials available for specific applications
Whether it’s a pair of skis or a vinyl window being produced, injection molding is efficient and economical, especially if it’s a large number of items that is being produced. The only real disadvantage is initial start-up costs such as necessary equipment, expertise and resources required for mold design.
Injection molding is the most common form of plastic part engineering and it is used to create a huge variety of complex parts of different size and shape. Products can be produced in a complex way that makes the process difficult to duplicate and at a fraction of the price. When you stop to think about the role plastics play in our everyday lives, it’s difficult to imagine a life without this substance. Some plastics are actually stronger than steel and they are more durable than most any substance on earth. Not only that, they are also relatively inexpensive to produce and reproduce over and over again.