The application of injection molding in the production of automotive parts

March 22, 2023

Advantages of injection molding in automotive applications

Injection molding is a well-established production process in which an automotive mold maker injects molten plastic material into a mold cavity. The molten plastic then cools and hardens, and the manufacturer extracts the finished product. Although the mold design process is critical and challenging (poorly designed molds can lead to defects), injection molding itself is a reliable method for producing solid plastic parts with a high-quality finish.

Here are a few reasons why the process is beneficial for the production of automotive plastic parts.

1. Repeatability
In the automotive industry, repeatability - or the ability to consistently produce the same part - is critical. Because automotive plastic injection molding typically relies on a robust metal mold, the final molded automotive part produced using that mold is virtually identical. Certain factors can affect injection molding, but if the mold has good design and finishing, injection molding is a highly repeatable process.

2. Size and Cost

The injection molding process can be an expensive process due to the cost of the mold. However, it is still a highly scalable process, and as manufacturers make more parts, their total cost decreases. For mass production applications, injection molding is therefore beneficial to the manufacturer. However, for anything that is not mass-produced, injection molding costs may inhibit the cost efficiency of the process.

3. Material availability
A significant advantage of using injection molding in automotive production is that the process is compatible with a wide range of rigid, flexible and rubbery plastics. 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 that achieve high surface finish quality. Manufacturers have many surface finish options for producing parts, including a variety of surface textures (e.g., glossy, rough or matte) that are applied directly to the mold rather than to 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 a molded automotive part to fit the vehicle's color scheme. Unlike other processes, injection molding allows you to mix dyes with the raw material pellets before manufacturing begins. This produces a solid, consistent coloring after molding is complete, without the need for painting or tinting.
6. Rapid Prototyping with Rapid Tooling
While automakers use injection molding extensively to mass produce automotive parts, they also use it as a prototyping tool. By using rapid tooling to create fast, low-cost aluminum molds - often through additive manufacturing or CNC machining - automotive toolmakers can produce low-volume prototype automotive parts much faster than traditional (steel) molds.