Principle, technology and application of two-color mold

Two-shot mould is an injection moulding process used to produce plastic products with two different materials or colours. It allows two materials to be injected in one moulding cycle, and through clever mould design and process control, versatile and diverse plastic products can be achieved.
1. What is a two-colour mould?
Two-colour mould is a process of combining two different plastic materials (which can be of different colours or with different characteristics) in the same injection moulding machine through two injection moulding processes.

2. Structural characteristics of two-colour mould
Two-colour mould consists of two sets of moulds, each set of moulds is responsible for one injection moulding respectively, the specific structure includes:
1. Main mould (fixed mould): usually fixed on one side of the injection moulding machine, used for the first moulding of plastic materials.
2. Dynamic mould (rotating mould): fixed on the rotatable mould platform, switching between two mould cavities through the rotating mechanism to complete the two injection moulding.
3. Sprue system: including gate, runner and other parts, respectively designed to adapt to the injection path of the two materials.
4. Mould locking mechanism: to ensure that the moulds are tightly fitted during the two injection processes to prevent material overflow.

3. The process of two-colour injection moulding
1. First injection: the first material is injected into the first cavity of the mould to form the base part or part of the structure.
2. Mould rotation or sliding: the moving mould rotates or moves to the second cavity position.
3. Second injection: Inject the second material to combine with the first moulded material to complete the product manufacturing.
4. Demoulding and picking up: the finished moulded two-colour product is taken out from the mould.

4. Advantages of two-colour mould
1. Aesthetics: Complex two-color or multi-color appearance design can be achieved without subsequent spraying or assembly.
2. Functionality: can combine the characteristics of different materials, such as soft and hard combination (hard plastic and elastomer combination).
3. High efficiency: one time moulding, reducing assembly process and improving production efficiency.
4. High precision: Seamless combination between two materials is ensured by mould processing precision.

5. Technical difficulties of two-colour mould
1. Complex mould design: precise design of rotating mechanism, cavity matching and pouring system is required.
2. Material selection and matching: to ensure that the two materials have good adhesion and compatibility, to avoid delamination or detachment.
3. Injection moulding process control: the pressure, temperature and time during the two injection moulding processes need to be precisely controlled to avoid air bubbles, shrinkage or deformation problems.
4. High equipment requirements: two-colour injection moulding machine or equipment with multi-station rotary function is required.

6. Difference with traditional moulds
traditional mould: usually used for single material and colour products, complex appearance or multi-material products need subsequent assembly.
Two-colour moulds: complete multi-material or multi-colour moulding in one go, reducing production steps and improving product quality.