• 2023-10-05
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Injection mold function

Injection mold is a complex system, which must simultaneously meet many requirements in the injection molding process. The primary function of the mold is to contain the polymer melt in the mold cavity, so that the opening cavity can be filled to form a plastic part with the same shape as the mold opening cavity; The second is the efficient transfer of heat from the hot polymer melt to the cold die steel, making the injection molding products as consistent and economical as possible; The third main function of the mold is to remove the product from the mold in a quick and repeatable manner so that subsequent molding can be carried out efficiently.

These three main kinetic energy - melting, heat transfer and removal of the product - also include the secondary requirements of the injection mold. Figure 1.3 provides a partial hierarchy of injection mold functions. For example, the functional requirements for the inclusion of melt in the mold are:

The mold must be able to withstand huge forces, which often cause the mold to open or deform.

The mold shall include a pouring system to connect the nozzle of the injection molding machine to the cavity of the mold for the transfer of the polymer melt.

These secondary functions may also give rise to third level functions, which are dependent on specific mold components.

It should be realized that Figure 1.3 does not fully list all the functions of the injection mold, but only some of the primary and secondary functions that must be considered in the engineering design of the injection mold. Even so, a skilled design engineer may recognize that conflicting requirements in mold design can be met through a variety of functions.

For example, effective cooling can be achieved by using multiple closely spaced cooling channels that conform to the mold cavity. However, in order to push out the product, it may be necessary to use more than one push rod in a specific position, and these positions may conflict with the cooling channel. At this time, the mold design engineer should consider the relative importance of the conflicting requirements, and the result can be a satisfactory mold design. When in doubt, novice design engineers tend to prefer redundant designs. This tendency should be avoided, as it can lead to large, expensive and inefficient molds.