The difference between Two-color mold and overmold

- Mar 15, 2018-

             Two-color mold: Two kinds of plastic materials are injected on the same injection molding machine, which is divided into two forms, but the product is only used for one-time mold. In general, this molding process is also referred to as two-shot molding and is usually completed by a set of molds and requires a special two-color injection molding machine. Wei Xun two-color mold plastic mold (secondary molding): two kinds of plastic materials may not be injected on the same injection molding machine, divided into two molding; products from a mold out of the mold, and then into another set of mold In the second injection molding. Therefore, in general, this molding process is usually completed by two sets of molds without the need for a special two-color injection molding machine. 

           Overmold, two-color mold and covered mold Overview: Cover plastic mold in the design should pay attention to the positioning of hard plastic parts, need to be sealed plastic and in the plastic parts have reverse tilt holes to prevent the plastic deformation. Two-color molds are increasingly popular on the market. This process can make the appearance of products more beautiful, easy to change color and can not spray, but the cost is expensive and technical requirements are high.


1. The two shapes of Cavity are different, and one product is formed separately. The two Cores are exactly the same shape. 2. Before and after the mold's front and rear molds rotate 180o in the center, they must match. This check must be done at design time. 3, pay attention to the position of the thimble hole, the minimum distance 210mm. Large molds must be properly increased in the number of holes in the top bar. In addition, since the ejector attached to the injection molding machine itself is not long enough, an extended ejector pin must be designed in our mold, and the ejector pin should be about 150 mm long. Two positioning rings must be designed on the rear mold base plate. 4. The total thickness of the front mold panel plus the A plate must not be less than 170mm. Please check the other reference data of this type of injection molding machine carefully, for example, the maximum mold thickness, the minimum mold thickness, the top hole distance and so on. 5, three-plate nozzle can be designed to automatically release the action. Special attention should be paid to the release of the soft glue mouth. 6. The depth of the front SPRUE should not exceed 65mm. The distance from the top of the SPRUE on the upper side to the center of the mold blank is not less than 150mm. 7, in the design of the second injection of CAVITY, in order to avoid CAVITY insert (or wipe) injury first formed a good product gel, you can design part of the avoidance. However, the strength of each sealant must be carefully considered. That is, whether or not there will be plastic deformation under large injection pressure in the injection molding, which may result in the possibility of a batch front arising from the second injection molding.

8. When injection molding, the size of the first injection molded product can be slightly larger, so that it can be pressed tighter with another CAVITY during the second molding to achieve the function of sealing. 9. Note that in the second injection molding, will the flow of plastic impulse the product that has been formed for the first time to deform the gel position? If this is possible, it must be improved. 10. Before clamping the A and B boards, please pay attention to whether the front mold Slider or Lifter will reset and crush the products first. In this case, you must find a way to make the A and B boards clamp before the SLIDER or LIFET of the front mold. Reset. 11, two CAVITY and CORE's water distribution arrangements as far as possible, and balanced, the same. In 12.99% of the cases, the hard plastic portion of the injection molded product was first injected, and the soft plastic portion of the injection molded product was re-injected. Because soft plastic deformation.