The Facts About Injection Molding

9 min read
The Facts About Injection Molding

You can find countless products in vehicles, homes, and businesses that were made using injection molding. The popularity of this manufacturing process stems from its efficiency, affordability, accuracy, and versatility. While thermoplastic polymers make up the bulk of materials used in injection molding, glass and metals are also used.

The injection molding process is described as a four-stroke cycle. First, an internal cavity that is the negative of the final product is injected with a molten form of the raw material. The material is then rapidly cooled, forcing it to harden. The mold then opens and the final product is ejected with metal pins.

From here, the mold closes again, and the process repeats itself. For smaller parts, numerous components can be produced within a mold with multiple cavities. This fairly simple system makes injection molding a critical backbone industry that thousands of companies around the world rely on to manufacture their products.

Injection Molding

Here are some key facts about injection molding

Key Advantages

The following advantages are what makes injection molding as popular as it is today:

  • Consistency:

For high-volume production and companies that value brand consistency, injection molding is ideal as the parts that follow the first one to be produced are virtually identical.

  • Accuracy:

Once a credible design has been put together by the in-house department or a design firm, you can expect a highly accurate and detailed product to be produced. There is little room for error in injection molding. Parts can be made accurate to 0.005 inches.

  • Minimal waste:

Since the raw material starts out in molten form, you can combine more than one material to synthesize the properties you desire. This process is called co-injection molding. Since excess material, of which there is usually very little, can be repurposed, there is minimal waste as well. Any excess material that cannot be reused is often sold to another factory that can make use of it.

  • Flexibility:

Another advantage of the raw material starting out in liquid form is that you can combine a variety of colors, allowing you to quickly change the visual properties of your product. Additionally, you can combine different materials to produce a product that is stronger, more flexible or resistant to ultraviolet light.

  • Affordability:

There are two cost factors that make injection molding affordable. The first is speed. Compared to machining plastic parts, injection molding is 25 times more cost-effective per unit on average. The other factor is that the bulk of the process is automatic, which means labor costs are very low.

  • Speed:

Finally, a major reason why manufacturers, especially those who need a mass-production solution, choose injection molding is that it is extremely fast. Cycles usually take between 15 and 30 seconds, while more intricate molds may take a little longer.

Injection Molding

New Injection Molding Technologies

As efficient and effective as it is, injection molding companies are always looking to innovate and improve the manufacturing process. For instance, micro-molding is a new trend that is ideal for companies that need highly precise and small parts. This is especially useful for tech companies that need small components for their devices.

RFID tags are also being incorporated into part production. Another interesting new technology is the Printed Injection Molding Tool or PIMT. This process will be useful in prototype injection molding where a lower number of parts are required. PIMT will allow baseline steel tools to be fitted with 3D printed inserts, which is useful for certain scenarios.

Finding an Injection Molding Company

If you’re looking to use injection molding to produce your products, finding a reputable company is imperative. This will help you obtain the best parts as quickly as possible and in a cost-effective manner.

Rapid Direct Injection Molding is a popular company that offers low volume injection molding and custom injection molding solutions. You can use them to develop prototype molds of your products, as well as short-run productions and a variety of other solutions.

Injection Molding Alternatives

Put simply, there isn’t a more suitable manufacturing process for large scale use. Injection molding comes out on top here. However, there are some alternatives that might be better suited to small-scale operations. This includes the following:

Spin Casting: Instead of the steel mold that’s typically used in injection molding, spin casting uses one made of rubber. The benefit is that the rubber molds are cheaper to produce. However, they don’t last as long as steel molds.

3D Printing: Recent advances in the past few years have made 3D printing an increasingly popular manufacturing process. Different designs can be produced at a faster rate but again, this process is not as efficient or suitable for large scale manufacturing as injection molding.


Injection molding is a powerful innovation that has revolutionized the manufacturing industry. As we move forward, it will be exciting to see what the future holds for injection molding. We might see new technologies very soon and there’s no telling just how much the industry will improve as a result.

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