What problems should be paid attention to in the design of two-color molds

Two-color mold is a mold in which two plastic materials are injected on the same injection molding machine, and the molding is divided into two times, but the product is only ejected once. Next, Heng zhao will tell you what problems should be paid attention to in the design of two-color molds.

1. The two shapes of the front mold are different, and one product is formed separately. The two shapes of the back mold are exactly the same. (Note: If there is a difference, make the front mold slider to ensure that the back mold is consistent)

2. After the front mold of the mold is rotated 180° from the center, it must be matched with the back mold. This must be paid attention to when designing.

3. When designing, please carefully check the parameter data of the two-color injection molding machine, such as the maximum mold tolerance thickness, the minimum mold tolerance thickness, and the distance between the top rod holes, etc.

4. The nozzle of the three-plate mold should be designed to automatically release the mold. Special attention should be paid to whether the demoulding action of the soft glue nozzle is reliable.

5. When designing the cavity for the second injection, in order to avoid inserting (or scratching) the cavity to damage 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, whether there will be plastic deformation under high injection pressure during injection molding, which may cause the possibility of cracking in the second injection.

6. During injection molding, the product size of the first injection molding can be slightly larger, so that it can be pressed tighter with another cavity during the second molding to achieve the effect of sealing.

7. Pay attention to whether the flow of plastic impulses the product that has been formed the first time and deforms the glue position during the second injection? If this is possible, we must find ways to improve it.

8. The water transportation arrangement of the two cavities and cores is as sufficient as possible, and balanced and the same.

9. In 99% of cases, the hard rubber part of the injection product is first injected, and then the soft rubber part of the injection product. Because the soft glue is easy to deform.

10. In order to make the two plastics "sticky" tighter, it is necessary to consider the "stickiness" between the materials and the roughness of the mold surface. Two-color injection molding has a special TPU; and the smoother the mold surface, the tighter they "stick".