Plastic injection mold is basically divided into static mold and dynamic mold. The injection head in the injection molding machine side of the gate sleeve for the static mold, the static mold generally has a gate sleeve, board, template composition, simple mold can also not use the board, directly with a thicker template can be. The gate sleeve is generally standard, unless it is for special reasons, it is not recommended to cancel it. The use of gate sleeve is conducive to the installation of mould, convenient replacement, and no polishing. Some special mold gate sleeves can be cut out or taper lines. The ejection mechanism of the static die must also be added when the part die must be demoulding. The structure of moving die is generally made up of movable template, dynamic die plate, demoulding mechanism, die foot and mounting plate.

In the demoulding mechanism, besides the stripping rod, there are return rods, and some molds also need to add springs to achieve such functions as automatic demoulding. And the guide pillar, cooling water hole and runner are also the basic structure of the die. Of course, the inclined guide die also has oblique guide box, inclined guide pillar and so on. When designing a mold for a product, the basic structural dimensions of the mold must be set to prepare the material to speed up the mold manufacturing. Complex products should first draw a good product map, and then set the size of the mold.

Now the mold is basically heat treatment, increase the hardness of the mold, improve the service life of the die. Before heat treatment, the formwork is preliminarily machined: drilling guide post hole, return hole (dynamic die), cavity hole, screw hole, gate sleeve hole (dynamic die) cooling water hole, milling runner, cavity, some molds should also be milling inclined guide box, etc. At present, the common precision mold template generally used cr12, Cr12MoV and some professional die steel, Cr12 and other hardness can not be too high, often cracked at HRC 60 degrees, the common hardness of the template is generally about HRC 55 degrees. The hardness of the core can be above HRC58. If the material is 3Cr2w8v, the hardness of the surface after nitriding should be above HRC58, and the thicker the nitriding layer, the better.

The gate is directly related to the beautiful appearance of the plastic parts. If the gate design is not good, it is easy to produce defects. It is easy to generate snake like flow without any obstruction. For demanding products, overflow and exhaust should also be designed. The overflow point can be used with the ejector pin, and there is no overflow overflow on the template, so that the service life of the die will not be affected. Mold design software is also increasing, most of them rarely use pencil to draw the mold map.