The mold designer must have a wealth of design solutions and experience in injection molding, and must take into account the relationship between this influencing factor and the injection molding standard, as well as the apparent factors, such as injection molding pressure, mold core working pressure and filling rate, and injection melt temperature, injection mold temperature, mold structure and gate method and arrangement, as well as the gate section, product wall thickness, the composition of the filler in the plastic raw material, and the crystal grain size and tendency of the plastic raw material. The influence of these elements is also different due to the difference of plastic raw materials, or other molding standards such as temperature, environmental humidity, re-crystallization, and changes in injection molding machines for injection molding.
Among the relevant elements of precision injection molding, the injection mold is an important factor for obtaining fine plastic products that meet the quality requirements. The design of the injection mold will affect the quality of plastic products. Because the specifications of the injection mold cavity are obtained from the specified specifications of plastic products and the shrinkage rate of commonly used raw materials, and the shrinkage rate is often a standard value within a range strongly recommended by the plastic manufacturer or the plastic guide of the engineering project. The gate method and gate position of the mold are related to the arrangement, and are related to the crystal tendency of the plastic in the engineering project, the appearance of the plastic product, the distance and the position from the specification to the gate. The key factors that effect the shrinkage rate of plastics include heat shrinkable film, change shrinkage, trend shrinkage, and ductility response. These influencing factors are related to the forming standards or actual operating standards of precision injection molding.
Because the whole process of injection molding is the process of changing the plastic from solid to liquid to solid. From powder to solution, and then from solution to product, the effects of temperature field, flow field and relative density field must be experienced in the middle. Under the mutual effect of this field, different plastics have different polymer structures and thixotropic properties.