Two color mold design and injection should pay attention to matters include:
- The water transport arrangement of the two cavities and the core should be as adequate as possible, balanced and consistent.
- After the front mold is rotated 180º from the center, it must match the rear mold. This must be noted when designing.
- In 99% of cases, the hard rubber part of the product is injected first, and then the soft rubber part of the product is injected. Because soft glue is easy to deform. Plastic materials with a high molding temperature are molded first, and then those with a low molding temperature.
- The nozzle of the three-plate mold should be designed to automatically release the mold. Pay special attention to whether the demoulding action of the soft glue nozzle is reliable.
- When designing, please carefully check the parameter data of the two-color mold injection molding machine, such as the maximum mold thickness, minimum mold thickness, ejector hole distance, etc.
- During injection molding, the size of the first injection molded product can be slightly larger so that it can be pressed more tightly with the other cavity during the second molding to achieve the sealing effect.https://solidcomould.com/product/plastic-yellow-baby-chair-mould/
- The two shapes of the front mold are different, and one product is formed respectively. The two shapes of the rear mold are exactly the same. (Note: If there is any difference, a front mold slider must be made to ensure that the rear mold is consistent)
- Pay attention to the second injection molding. Will the flow of plastic affect the product that has been formed in the first time and cause the plastic position to deform? If this is possible, we must find ways to improve it.https://doi.org/10.1016/j.polymertesting.2022.107759
- In order to make the two plastics “stick” tighter, the “stickiness” between the materials and the roughness of the mold surface must be considered. Two-color mold injection molding has a special TPU; and the smoother the mold surface, the tighter they “stick”.
- When designing the cavity for the second injection molding, in order to avoid inserting (or scratching) the cavity into the glue position of the product that has been formed for the first time, a part of the cavity can be designed. However, the strength of each sealing position must be carefully considered, that is: in two-color mold injection molding, whether the plastic will deform under high injection pressure, resulting in the possibility of sharp edges in the second injection molding.
