Plastics in the U.S. is a $371 billion industry. Plastic parts are useful because they can combine strength and durability with light weight.
This makes them a popular option for many different industries, including automotive, aerospace, consumer goods, electronics, medical devices, and more. Such advantages are only achievable through innovative production processes, such as injection molding.
How does injection molding work? This article answers that question and explains some of the benefits of this manufacturing process. Keep reading to learn more.
How does injection molding work?
The first step in plastic injection molding is design. First, the material for the part is chosen. Producers can select the best thermoplastic type and composition to suit the end goals of the component.
The next step is the mold design process. The mold usually consists of two halves made of metal (typically steel or aluminum) with a negative core and cavities.
Then, the thermoplastic–usually in the form of pellets or granules–is melted down to a molten state. A very specific temperature is achieved inside the barrel of the heating mechanism.
A rotating screw or plunger then injects the molten plastic into the mold cavity through a nozzle. Pressure is important in this step as it ensures the plastic completely fills all space in the mold.
Once the mold is filled, the material cools and solidifies. Sometimes controlled temperatures are used to limit shrinkage or warping of the part. Finally, the mold is removed and the final part is ejected.
Types of Injection Molding
Beyond the basics of “How does injection molding work?” there are subprocesses to consider. Thermoplastic injection molding is the most common type. It encapsulates the processes described in the previous section. However, there are many variations of this.
Liquid silicone rubber molding is another type of injection molding. It uses thermoset materials, which rely on a chemical reaction to create a plastic part. These cannot be remelted once they form.
Insert molding begins with a component being placed into the mold before the resin enters. The plastic flows around the insert to form the final part.
Overmolding is another distinct injection molding process. It combines two or more components molded over the top of one another.
What Are the Benefits of Injection Molding?
There are many distinct advantages of injection molding. One is high efficiency. Once tooling is completed, it is possible to produce high volumes of parts very quickly.
This is combined with the great precision that injection molding affords. It is possible to create intricate or complex shapes with consistent accuracy and quality.
Another big plus of injection molding is cost savings. While it requires a tooling investment upfront, the per-part output costs can be much lower than most other production methods.
A final advantage of injection molding is that it is sustainable. Excess plastic can be reused in subsequent processes, so there is minimal waste.
Learn More about Manufacturing with Injection Molding
Having answers to “How does injection molding work?” gives you a better grasp of the advantages the process offers. An experienced manufacturer can discuss with you the distinct benefits related to your project or industry needs.
Nova Stevensville maintains a 100,000-square-foot plastic injection molding operation in southwest Michigan. We supply automotive parts to both tier-one and tier-two manufacturers. Contact us today to learn more.
