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Difference between two color mold and over mold

Posted by: Mu Ju 2021-10-30 Comments Off on Difference between two color mold and over mold

A. Two color mold: two kinds of plastic materials are injected on the same injection molding machine, which are molded twice, but the product only produces the mold once. Generally, this molding process is also called double injection molding, usually completed by a set of moulds, and requires a special two-color injection molding machine.

Over molding): two kinds of plastic materials are not necessarily injected on the same injection molding machine, and are molded in two times; after the product is taken out of one set of moulds, it is put into another set of molds for the second injection molding. Therefore, generally, this molding process is usually completed by 2 sets of moulds, without the need for a special two-color injection molding machine.

Overview of two color mold and over mold:

The design of over mold should pay attention to the positioning of the hard adhesive parts, and the adhesive can be sealed with reverse angle holes on the adhesive to prevent the deformation of the glue pulling

The double color mold is becoming more and more popular in the market. In this process, the appearance of the product can be more beautiful, and it is easy to change color without spraying. However, it is expensive and requires high technical requirements

1. The two shapes of cavity are different, forming one product respectively.

And the core has the same shape.

2. after the front and rear die of the die are rotated 180 o in the center, it must be consistent. This check action must be done in design.

3. pay attention to the position of the top pinhole, with a minimum distance of 210mm. The number of top rod holes shall be increased appropriately for large moulds. Moreover, because the thimble attached to the injection molding machine is not long enough, we must design an extended thimble in our mold, which is about 150 mm longer than the base plate of the mold embryo. Two locating rings must be designed on the bottom plate of the rear mold.

4. the total thickness of front formwork panel plus a plate shall not be less than 170mm. Please carefully check other reference data of this type of injection molding machine, such as maximum mold thickness, minimum mold tolerance thickness, top rod hole distance, etc.

5. the nozzle of the three board mold should be designed to automatically release the mold. Pay special attention to the feasibility of the release action of the soft glue nozzle.

6. the depth of front sprint shall not exceed 65mm. The distance from the top of sprue on the upper side (big water port) to the center of mold embryo shall not be less than 150 mm.

7. when designing the second injection molding, in order to avoid the injection (or scratch) of the molded product glue position for the first time, a part of the plastic can be designed to avoid air. But the strength of each sealing position must be carefully considered, that is, will plastic deformation occur under large injection pressure during injection molding, which may lead to the possibility of batch front in the second injection molding?

8. during injection molding, the product size of the first injection molding can be slightly larger so that it can be pressed more tightly with another cabinet in the second molding to achieve the sealing effect.

9. note whether the flow of plastic will impulse the products that have been formed for the first time to deform the glue position during the second injection molding? If there is a possibility, we must find ways to improve it.

10. before closing the A and B plates, please pay attention to whether the slide or lifter of the front die will reset and crush the product first? In this way, we must find a way to make the die close first in a and B boards, and then the slide or live of the front die can be reset.

11. the water transportation arrangement of both cability and core shall be as full as possible, and be balanced and the same.

12.99% of the cases are the hard plastic part of the injection product first, and then the soft part of the injection product. Because soft glue is easy to deform.



About PTJMould Industrial Company Limited

PTJmould is a China mold maker of plastic molds- injection mold, die casting moulds, plastic blow molding, rotational molding, medical plastic injection molding, two shot plastic injection molding, insert molding, overmolding, metal injection molding, micro injection molding, powder injection molding, ceramic injection molding, liquid injection molding, husky injection molding, household mold, casting mold, die mold tool, custom molds, china moulds, rapid prototyping tooling, plastic prototyping tooling, punch press tooling, die and tooling for mobile/ cell phone parts, automotive parts, vacuum cleaners, rechargeable tools, telephones, copiers, computers, multimedia speakers, and many other electronic products and household appliances. And also a plastic product manufacturer, mold manufacturer China– plastic parts, plastic water tank, plastic balls, plastic containers, plastic buckle, plastic anchor, plastic hanger, plastic spoon, plastic pipe fitting, plastic tumble, plastic tableware, plastic cups, plastic bottles, plastic tray, plastic cosmetic container, plastic case, plastic food container, plastic chairs, plastic caps, plastic cap closure, plastic tubes, plastic water pipes, plastic knobs, plastic tubing, plastic utility boxes, plastic racks and so on.

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