Differences of Overmolding And Two-Color Molding

Differences of Overmolding and Two-Color Molding

When we speak with friends or customers new to the mold industry, they often get confused between overmolding and two-color molding processes. 

This article aims to clarify those differences and provide valuable insights. Let’s dive in and learn more!

1. What is overmolding ?

Overmolding (Secondary Molding): Overmolding involves molding two different types of plastic materials, which may not necessarily be done on the same injection molding machine. The process requires two separate molding cycles: after the product is ejected from the first mold, it is then placed into a second mold for the second injection molding. When designing overmolding molds, it is crucial to ensure proper positioning of the hard plastic components and reliable sealing of the overmolded material. The overmolded component should also include draft angles to prevent deformation during the molding process.

Overmolding molds must account for the dimensions of the overmolded parts, the accuracy of overmolding processing, mold precision, product positioning, and handling. Compared to standard injection molds, overmolding molds require significantly higher precison. Although two-color molding also demands high precision, overmolding is generally more complex. Two-color molding is performed on the same injection molding machine, with the product not yet fully cooled, so dimensional fluctuations from the initial molding are less noticeable.

2. What's the Applications of Overmolding Process ?

Overmolding is widely used in a variety of fields including aesthetic products, conductive items, terminal blocks, metal handles, reinforced products, waterproof products, electrical appliances, beauty products, baby products, small Commodity appliances, fans, new energy vehicles, gaming consoles, sports equipment,automotive lampshade,motorcycle parts and more.

3. The study case of overmolding in Guangchao Mould

For example, in a recent project, Guangchao Mold produced a mold for motorcycle decorative trim fram. During the injection molding (overmolding) process, we first placed pre-manufactured soft rubber components in their corresponding positions within the mold. The machine then carried out the injection, resulting in the final product.

Please find below overmolding video to know more about process : We can clearly see in the video that the staff first places the pre-manufactured soft rubber components in their correct positions within the mold, and then the injection molding process is carried out on the machine to produce the final product.

Of course, designing overmolding molds comes with its challenges. It is essential to consider the successful integration of different materials and the ease of part ejection. We welcome collaboration and can offer our extensive experience along with professional advice and solutions.

4. What is Two-Color Molding ?

Two-Color Molding: This process involves injecting two different plastic materials on the same injection molding machine, but it is done in two stages, with the product being ejected from the mold only once. This technique, also known as dual-material injection molding, typically uses a single mold and requires a specialized two-color injection molding machine.

Two-color molding is increasingly popular in the market as it enhances the appearance of products, allows for color changes without painting, but comes with higher costs and technical demands. In two-color molding, the front and back molds must align perfectly after a 180° rotation of the center. This alignment check is essential during the design phase. It is also important to design the water sprue of a three-plate mold to facilitate automatic ejection. Special attention should be given to ensuring reliable ejection of soft plastic water sprues.

5. What is the applications of Two-Color Molding ?

Two-color molding is widely used in electronic products, power tools, medical devices, home appliances, toys, and almost all areas of plastic products. The development of two-color molds, molding techniques, and related machines and materials has advanced rapidly. At Guangchao, our mission is to master core injection molding technologies, engage in technical exchanges with clients before mold production to ensure short delivery times, long mold life, rapid mass production, and high-quality final products. For any injection molding needs, please feel free to contact us! 

6. The study case of Two-Color Molding in Guangchao Mould

Using the motorcycle taillight housing mold as an example, please find below overmolding video to know more about process :This video showcases the production process of a three-color mold, which operates on the same principle as two-color molding. We use this video for illustration purposes. It clearly shows the staff removing a finished product, after which the mold rotates 180° on the machine to enter the next injection phase (using different materials or colors). This crucial step is referred to as "mold core roration".

Overmolding VS Two-Color Molding

Summary of Overmolding and Two-Color Molding

This article outlines the differences and applications of overmolding and two-color molding.

1. Overmolding is a secondary molding process that involves injecting two different plastic materials, often using separate machines. It requires precise mold design, considering material integration, accurate positioning, and draft angles to prevent deformation. Common applications include aesthetic products, conductive items, and automotive parts. A case study from Guangchao Mold illustrates the process using motorcycle decorative trim, highlighting the challenges of material integration and part ejection.

2. Two-Color Molding involves injecting two plastic materials in two stages on the same machine, using a single mold. It enhances product appearance and allows for easy color changes without painting, though it requires precise alignment and specialized machinery. Applications span various industries, including electronics and medical devices. Guangchao Mold emphasizes its expertise in this area, focusing on efficient production and high-quality outcomes.

Both processes showcase Guangchao Mold's commitment to quality and innovation in injection molding solutions. Welcome to contact us !