Injection molding is an established production process in which automotive moldmakers inject molten plastic material into mold cavities. 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 of producing solid plastic parts with high-quality surfaces.
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 solid metal mold, the final molded auto part produced using that mold is virtually identical. Several factors are associated with 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 manufacturing process can be an expensive process due to the cost of the mold. However, it is still a highly scalable process, and its overall cost decreases as the manufacturer manufactures more parts. For mass production applications, injection molding is therefore beneficial to manufacturers. However, for any product that is not mass produced, injection mold cost can inhibit the cost efficiency of the process.
3. Material availability: A significant benefit of using injection molding in automotive production is the wide range of rigid, flexible and rubber plastics that the process is compatible with. Manufacturers use a variety of different polymers in 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 geometry and can achieve high surface finish quality. Manufacturers have many surface treatment options when producing parts, including various surface textures—such as glossy, rough, or matte—that they apply directly to the mold rather than molding the 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 suit the vehicle's color scheme. Unlike other processes, injection molding allows you to mix dyes with raw material pellets before manufacturing begins. This produces a solid, consistent color without the need to paint or tint after molding is complete.