close-up of small, blue plastic parts

Injection-molded plastic parts


Injection molding can create parts used in all sorts of projects and industries. From cars to computers, motorcycles to models, plastic injection molding is how modern products get made. In fact, plastic parts made with injection molding surround each of us every day.

Plastic parts are so appealing to businesses because they are efficient to build, reliable to use, and affordable to mass-produce. To learn more about how plastic injection molding works, click here.

Injection molding is best suited for larger projects; production runs needing at least 100 units. Once you’ve created your mold, the more you produce, the lower your cost per unit.


Injection mold making


Molds are created in different ways to do different jobs. Some molds are made from aluminum. These are generally cheaper and do not last beyond a few thousand cycles. Rex Plastics uses tool steel to create our molds. These steel molds can last for millions of cycles and come with a lifetime warranty.

The lifetime of your mold will depend on many factors. Generally, the product being produced will have the greatest impact on the lifespan of your mold. Some parts will require extreme temperatures or pressures, and these elements will take a toll over time. 

The material your parts are made from can also have an impact on your mold. Common materials include:

  • Polypropylene
  • Polyethylene
  • Acrylonitrile Butadiene Styrene (ABS)

Each of these materials has its advantages and disadvantages, which is why, when determining which material to work with, you need to think of how the final product will be used. Will it need to be food-safe? Does it need to be heat tolerant? UV resistant? These are some of the things you need to consider before deciding which material to use. To read more about plastic materials used in injection molding, check out our blog here.

When you work with Rex Plastics, you get a mold you can count on. Crafted by experts with decades of experience, our computer-assisted design molds are the best in the business.

small plastic parts used to cool computers


Plastic parts manufacturing


To fully appreciate one of the key benefits of plastic parts made with injection molding, it’s essential to first understand the price per unit. With injection molding, the bulk of the investment is made toward the start of the project with the actual creation of the mold. Once this is complete, the project becomes more cost-effective the more parts you create. 

If you create a mold for $5000 and then make 100 units, your cost per part will be $50. This price will drop the more units are made. Another way to decrease the price per unit is with a larger mold. The more cavities in your mold, the more pieces can be created at once and the more cost-efficient your project becomes.

An injection mold can cost anywhere from $1,000 up to $80,000, sometimes more for complex parts. In most cases, the average cost is between $10-$20,000. One of the most important factors to consider for your project is the return on investment. That return increases based on the number of parts being created, just as the cost per unit decreases. Put simply, bigger projects recoup the upfront costs faster. Main factors that can impact the total project budget include:

  • Complexity
  • Material
  • Part size
  • Quantities


Your plastic parts experts

Rex Plastics is an industry leader in manufacturing and design. When starting a project, it’s important to go with a partner you can trust. Rex Plastics has been helping clients realize their goals since 1971. In that time, we’ve proven ourselves to be one of the best producers of plastic parts in the country. If you have a project that you’d like to pursue, contact us today.