Introduction to overmolding
Overmolding, also known as overshoot molding or two-shot injection, is a special injection molding technique used to add additional color, material, or texture to the surface of a molded part.
Overmolding and post-coating of brush heads
The process of overmolding
1. Preparations:
First of all, it is necessary to prepare two or more injection plastics of different colors or materials and load them into different injection molding machine hoppers separately. Each hopper has an independent heating and injection system.
2. First injection molding:
The injection plastic of one color or material is first heated and melted, and it is injected into the mold through the injection system to form the bottom or base part of the part.
3. Mold transposition:
After the first injection is completed, the mold is rotated so that the surface to be injected is exposed in front of the injection molding machine's injection system.
The mold is transposed
4. Second injection molding:
Next, the injection plastic of another color or material is heated and melted and injected into the mold through an injection system, covering the surface of the molded part. The injection plastic injection of the second injection will bond with the bottom material of the first injection to form a monolithic bi-color or multi-color part.
5. Cooling and demolding:
After the injection molding is completed, the mold will cool down for a period of time to ensure that the injection plastic cures. Then, the mold opens and the finished two-color or multi-color part is removed from the mold.
The above is an example of the process of overmolding, the demonstration of the two-color mold can be seen in the video of NX Little Prince at Station B, and the example demonstration picture above is from the video with him.
Advantages of overmolding
Multi-color/multi-material combination: Through overmolding, different colors or combinations of different materials can be achieved to create rich and diverse appearance effects.
Combination of different materials and different colors
Improve the appearance texture: Overinjection molding can form details such as texture, pattern or text on the surface of the product, improving the appearance and visual appeal of the product.
A bear pattern is formed by overmolding. Add cute attributes to the product.
Overmolding creates a green texture, which increases product detail and enriches product visual effects
Enhanced functionality: Through overmolding, functional parts or special structures can be added to the product to improve the performance and user experience of the product.
Save production costs: Compared with traditional assembly methods, overmolding can reduce the number of parts and assembly process, simplify the production process, and reduce production costs and labor costs.
Improve product quality and consistency: Overmolding can realize the integrated production of parts, reduce assembly errors and loosening problems, and improve the quality stability and consistency of products.
Improve production efficiency: Overmolding usually uses automated production lines, which can achieve efficient production and large-scale production.
Disadvantages of overmolding
Design limitations: The design of overinjection molding needs to consider factors such as material compatibility, structural complexity and cost, which may bring certain restrictions to product design.
High technical requirements: the production process of overinjection molding requires professional equipment and technology, and has high requirements for the technical strength and experience of manufacturers.
High initial investment: The establishment of a secondary injection molding production line requires a certain initial investment, including equipment purchase, technical training, etc., which may have high cost pressure for manufacturers.
Difficulty of after-sales maintenance: Because the products of overinjection molding are integrated, if the product needs to be repaired or replaced due to quality problems, it may be more complicated and difficult than the traditional assembly method.
Overall, overmolding has obvious advantages in improving product appearance, function and quality, but it also requires trade-offs in terms of design, technology and cost. According to the specific product demand and market environment, the selection of appropriate production methods is key.
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