To determine the shrinkage rate, it is best to set the shrinkage rate twice when the same material is used for both injections and the product shape and size requirements are strict. However, it is necessary to consider the influence of the molded product after the first injection on the second injection when it is used as the second injection mold cavity. In the case that the proportion of the second injection molded product in the whole product is not large, the shrinkage rate of the second injection molded product may not be set. If the material of the second injection molding is silicon, rubber or relatively soft material, the shrinkage rate can usually not be set. Then, let's learn about it together.Suzhou two-color moldDesign requirements and design considerations!

Generally speaking, the shrinkage rate of the two-color type depends on the first injection of plastic, the second injection of plastic and the first injection of plastic choose the same shrinkage rate. For example, the plastic injected for the first time is ABS, and the plastic injected for the second time is TPE. The shrinkage rate of ABS is usually 0.5, and the shrinkage rate of TPE is usually 1.8. All are selected when designing the two-color injection mold.

For products with a logo (company logo or trademark), the gate selects the open side of the logo to facilitate the filling of the second plastic melt. The injection of the product selection latent gate, to ensure that the product and the runner can automatically cut off. When the latent gate cannot be used, three-plate type or hot runner can be considered. The disadvantage of three-plate type is that the pressure loss is large and the solidification material of the runner is much. Preservation. This is a professional term for two-color molds. The product of the first time will press the model chamber of the second time, so it is quite sensitive to the shape of the logo. Generally speaking, the height of the logo is 0.02mm and 0.05mm larger than the theoretical value, which is too small, the melt injected for the second time will enter, and the outline of the text is not clear. If the preloading is too large, the logo line will expand too much. Deflation slope. The drawing inclination of the first injection part of Suzhou two-color mold molding should be flexible and the angle should be as large as possible. The drawing inclination of the mark can be expanded to 15, and it is not easy to deform in the second injection melt by increasing the chassis.

When the first injection molding, the product size is slightly larger, and when the second molding is firmly pressed on another mold cavity, the sealing effect can be achieved. The size of the template for making the two-color mold must be exactly the same, and the position of the guide post hole must also be the same. The movable and fixed formwork of the 2 sets of formwork must be freely replaced, and the total height of the 2 sets of formwork must be the same. The 2 sets of fixed formwork and the 2 sets of movable formwork must be increased respectively, which must be specially stated when purchasing the formwork.

After the movable mold of Suzhou two-color mold is rotated and 180, the four guide posts of the movable mold must match the guide posts of the fixed mold. The standard frame of the commonly used injection mold has an offset guide post and guide sleeve, and the four guide posts, guide posts and guide sleeves of the two-color mold.

The movable and fixed molds of Suzhou two-color molds must be hard molds with a heat treatment hardness of 4852HRC.

For the two molded products formed by the two-color mold, in order to prevent the two sets of molds of the two-color mold from being inconsistent during manufacturing, it is necessary to have the same dimensional reference.

The design parameters of Suzhou two-color mold are consistent with the parameters of two-color injection molding machine. For example, the maximum allowable mold thickness, the minimum allowable mold thickness, etc. The total thickness of flat plate plus a plate should be above 170mm. Check whether the parameters of the injection molding machine, such as the maximum allowable die thickness, the minimum allowable die thickness and the distance between the ejector holes, meet the requirements. Attention k. The hole is the position from the top hole of the rod, and the general minimum distance is 210mm. Large mold must be appropriate to increase the number of holes on the rod. In addition, the upper rod attached to the injection molding machine itself is not long enough, so the mold must be designed to have a longer upper rod, which extends about 150mm from the template bottom plate. Two locating rings shall be designed on the movable formwork.

Generally, the hard rubber part of the product is first, and then the soft rubber part of the product is ejected. Since soft rubber is easy to deform, please note that the shrinkage rate varies with the type of two molding plastics.

The above introduction is the Suzhou two-color mold design requirements and design considerations, if you need to know moreMedical product molds, remote control molds, Suzhou two-color injection molding, can contact us at any time!