Experiences about two-color plastic case injection mold

1. If it is a two-color plastic case injection mold, it is a straight barrel, a 90-degree barrel injection, no rotation is required, only one mold core is needed, and the separation method of soft material and hard material relies on the position sealing.

2. The two shapes of the plastic shell injection mold cavity are different, and each molds a product. The two shapes of the punch are exactly the same.

3. The cavity and core of the plastic case injection mold must match after rotating 180° around the center. This inspection action must be done during design.

4. Pay attention to the position of the ejector hole, the minimum spacing is 210mm. Large plastic shell injection molds must appropriately increase the number of ejector holes. In addition, since the ejector that comes with the injection molding machine itself is not long enough, our plastic shell mold must be designed with an extended ejector, which is about 150mm longer than the mold base bottom plate.

5. Two positioning rings must be designed on the core side of mold bottom plate.

6. The total thickness of the cavity side panel plus A plate cannot be less than 170mm. Please carefully check other reference data of this type of injection molding machine, such as the maximum mold thickness, the minimum mold thickness, the ejector hole spacing, etc.

7. The depth of the front gate should not exceed 65mm. The distance from the top of the upper large sprue gate to the center of the mold base should not be less than 150mm.

8. When designing the plastic mold cavity for the second injection molding, in order to prevent the mold cavity from damaging the plastic shell material position that has been molded for the first time, a partial escape can be designed. However, the strength of each sealing position must be carefully considered, that is: during injection molding, will the plastic deform under high injection pressure, resulting in the possibility of flash in the second injection molding;

9. During injection molding, the size of the plastic shell molded by the first injection molding can be slightly larger so that it can be pressed more tightly with the other mold cavity during the second molding to achieve the effect of sealing.

10. Before the A and B plates are molded together, pay attention to whether the cavity convex or concave mold will be reset first and crush the product? If so, you must find a way to make the A and B plates molded first, and then the convex or concave mold of the front mold can be reset.

11. The cooling transport arrangement should be as sufficient as possible, and balanced and the same.

12. In most cases, the hard plastic part of the product is injected first, and then the soft plastic part of the plastic shell is injected. Because soft plastic is easy to deform.

13. Pay attention to whether the movement of plastic will affect the first molded product and deform its plastic position during the second injection molding? If this is possible, you must find a way to improve it.

14. Be careful when choosing the gate position for a two-color plastic shell mold. It is best to choose a sub-gate for the first plastic shell, so that the plastic shell and the runner can be automatically cut off. When sub-gate cannot be used, a three-plate mold or a hot runner mold can be considered. If the first material is a point gate, a sunken should be made to avoid the second material from being hit by the residual point of the first injection.

15. One of the most common two-color plastic shell molds is rotary injection mold. The cavity and core at two positions of the rotary injection mold requires consistent size and precision, and good cooperation with the moulds. When the ejection and demoulding mechanism on the two-color injection molding machine cannot be used, a hydraulic ejection and demoulding mechanism must be set on the turntable.

16. Two-color plastic shell mold injection molding usually uses the same plastic of different colors, or two different plastic raw materials. It is necessary to consider the interface effect of the two plastic raw materials, the difference in shrinkage rate, and the processing parameters.

Contact us to help you build best quality two-color plastic shell injection mold, send email to yoyo@hanking-mould.com.