The nozzle may not be in the center of the mold. If the mold is special, the nozzle can be designed to be off center. When installing the mold on the injection molding machine, the nozzle will be the center for installation. It should be noted that after the pump nozzle is offset, the ejector pin hole should also be offset together.

The size of that mold core can be circular. Anyway, the material to be ordered should be rigid enough to be fixed in the thinnest place, and the size of the nozzle is fixed. The gate depends on the characteristics, appearance and precision requirements of the plastic parts of the product.

The design of mold sprue sleeve size is based on the nozzle inner diameter of the mold using machine, and the size of sprue sleeve small head is comprehensively considered according to the inclination of cross sleeve, the weight of product, the fluidity of raw materials and the use temperature of mold.

According to the different conditions and processing methods of plastic mold, the basic performance requirements of steel for plastic mold are summarized as follows:

1, sufficient surface hardness and wear resistance.

The hardness of plastic mold is usually below 50-60HRC, and the mold after heat treatment should have enough surface hardness to ensure the mold has enough rigidity. Because the filling and flowing of plastic will produce great compressive stress and friction, it is required that the mold maintain the stability of shape accuracy and size accuracy, and ensure that the mold has sufficient service life.

2. Excellent machinability

Most plastic molding dies need cutting and fitter repair besides EMD machining. In order to prolong the service life of tools, improve the cutting performance and reduce the surface roughness, the hardness of steel used for plastic molds must be appropriate.

3, good polishing performance

High-quality plastic products require a small roughness value of the cavity surface. For example, the surface roughness of injection mold cavity should be less than Ra 0. 1 ~ 0.25, and the optical surface should be Ra.

Refer to the above content: Baidu Encyclopedia-Mold