Advantages of Injection Molding in Automotive Applications

Injection molding is a well-established production process in which automotive mold makers inject molten plastic material into mold cavities. The molten plastic then cools and hardens, and the manufacturer removes the finished part. While the mold design process is critical and challenging (a poorly designed mold can lead to defects), injection molding itself is a reliable method of producing solid plastic parts with high-quality finishes.

Here are a few reasons why injection molding is beneficial for the production of automotive plastic parts:

1. Repeatability

In the automotive industry, repeatability, or the ability to consistently produce the same parts, is critical. Since automotive plastic injection molding typically relies on strong metal molds, the final molded automotive parts produced using this mold are virtually identical. Several factors affect injection molding, but injection molding is a highly repeatable process if the mold is well designed and finished.

2. Scale and cost

The injection mold making process can be an expensive process due to the cost of the molds. However, it is still a highly scalable process whose overall cost decreases as manufacturers make more parts. Therefore, for mass production applications, injection molding is beneficial to manufacturers. However, as with any product that is not mass-produced, injection molding tooling costs can limit the cost-effectiveness of the process.

3. Material availability

A significant advantage of using injection molding in automotive production is the wide range of rigid, flexible and rubbery plastics with which the process is compatible. Manufacturers use a variety of different polymers for various applications in the automotive industry, including ABS, polypropylene, acrylic, acetal, nylon, polycarbonate, and more.

4. High precision and surface finish

Injection molding is ideal for producing plastic parts with relatively simple geometries and can achieve high surface finishes. Manufacturers have a variety of surface finish options when producing parts, including various surface textures (such as glossy, rough, or matte) that are applied directly to the mold rather than the molded part. However, different plastic materials can also affect the final surface finish.

5. Color options

In automotive plastic injection molding, it is easy to modify the color of molded auto parts to fit the vehicle's color scheme. Unlike other processes, injection molding allows you to mix dye with raw material pellets before manufacturing begins. This produces a solid, consistent coloration without the need for painting or staining after molding is complete.

6. Use Rapid Tools for Rapid Prototyping

Although automakers use injection molding extensively to mass-produce auto parts, they also use it as a prototyping tool. By using rapid tooling to create fast, low-cost aluminum molds, typically via additive manufacturing or CNC machining, automotive moldmakers can turn around short runs of prototype molded automotive parts much faster than traditional (steel) tooling.