Where is the design of two-color molds more complicated than single-color molds?

Update:04-06-2021
Summary:

A two-color mold is a mold in which two plastic materia […]

A two-color mold is a mold in which two plastic materials are injected on the same injection molding machine in two moldings. It is usually composed of two sets of molds. The rear mold must be rotated 180 degrees, while the front mold does not move, but the product is only ejected once. Generally, this molding process is also called two-color injection molding, and requires a special two-color injection molding machine.

The selection of two-color mold materials is a very important part of the entire two-color mold processing process, but the two-color mold design is also very important, which plays a decisive role in ensuring the normal production of two-color injection molds,Bucket mould  reducing failures and quality problems, and extending the service life of the mold. So what are the more complicated details in the design of two-color molds compared to ordinary single-color molds?

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

2. The mold base guide post and guide sleeve must be symmetrical up and down, and the front and back molds must be symmetrical.

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

4. The product spacing must be based on the spacing of the nozzles of the injection molding machine. The nozzle spacing of some foreign two-color injection molding machines is adjustable, some are not adjustable, and the domestic one is not.

5. Two independent ejection systems and two ejector rods. The two products of the back mold are the same, and the thimble is the same. It is a rotation relationship, and it must not be made into a translation relationship.

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

7. The side locks must be on the four sides of the mold center and the front and rear molds are symmetrical. Otherwise, when the rear mold rotates 180 degrees, it will not align with the front mold, which is not good.

8. If the distance between the glue feed point and the nozzle of the injection molding machine is different, the top rod hole should be waist-shaped, because the top rod spacing of the injection molding machine is not adjustable. Note: Most injection nozzles of domestic two-component injection molding machines are not adjustable.