Plastic molds are tools for giving complete structure and precise dimensions to plastic products in the plastic processing industry and are paired with plastic molding machines. According to different molding methods, they can be divided into different types of molds. By using various systems or auxiliary mechanisms in the mold, plastic particles are liquefied at high temperature and filled into the mold cavity to produce tools for industrial parts with specific shapes, sizes, functions, and qualities. Common types of molds can be classified into the following categories.
Single-face injection mold tooling
When the mold is opened, the moving mold and the fixed mold are separated to take out the plastic part, which is called a single-face mold, also known as a double plate mold. It is the simplest and most basic form of injection mold tooling, and can be designed as a single-cavity or multi-cavity injection mold according to requirements. It is the most widely used type of injection mold.
Double-face injection mold tooling
The double-face injection mold has two parting lines. Compared with the single-face injection mold tooling, an intermediate plate that can move locally is added to the fixed mold part of the double-face injection mold tooling, so it is also called a three-plate (moving plate, intermediate plate, fixed plate) injection mold tooling. It is commonly used in single-cavity or multi-cavity injection mold toolings with point gate feeding. When the mold is opened, the intermediate plate separates from the fixed plate at a fixed distance on the guide pin of the fixed plate so that the solidified material of the gating system can be taken out between these two plates. The double-face injection mold has a complex structure, high manufacturing cost, and difficult component processing. It is generally not used for the molding of large or extra-large plastic products.
Injection mold tooling with side parting and core pulling mechanism
When the plastic part has a side hole or recess, a movable core or slider is required for molding. After injection molding, the moving mold first moves downward a certain distance, and then the oblique surface segment of the pin fixed on the fixed mold forces the slider to move outward. At the same time, the push rod of the demoulding mechanism pushes the ejector plate to remove the plastic part from the core.
Injection mold tooling with movable mold parts
Due to the special structure of some plastic parts, it is required that the injection mold tooling be equipped with movable mold parts, such as movable male molds, movable female molds, movable inserts, movable thread cores or thread rings, etc. These can be moved out of the mold with the plastic part during the demoulding process, and then separated from the plastic part.
Automatic unscrewing injection mold tooling
For plastic parts with threads that require automatic demolding, a rotating thread core or thread ring can be set on the mold, which can be driven by the opening and closing action of the mold or the rotating mechanism of the injection molding machine or a special transmission device, in order to remove the plastic part.
Runnerless injection mold tooling
Runnerless injection mold refers to the method of insulation and heating of the runner, which keeps the plastic between the nozzle and the mold cavity in a molten state, so that there is no solidified gating system when taking out the plastic part. The former is called an insulated runner injection mold and the latter is called a hot runner injection mold.
Right-angle injection mold tooling
Right-angle injection mold tooling is only suitable for angle injection machines. It is different from other injection molds in that the direction of feeding during molding is perpendicular to the opening and closing direction. Its main runner is opened on both sides of the moving and fixed parting lines, and its cross-sectional area is usually constant, which is different from other molds used in injection machines . The end of the main runner can be provided with a replaceable runner lining block to prevent wear and deformation of the injection machine nozzle and the inlet end of the main runner.
Injection mold tooling with demoulding mechanism on the fixed mold
In most injection mold toolings, the demolding device is installed on the side of the moving mold, which is conducive to the work of the ejection device in the opening and closing system of the injection machine. In actual production, some plastic parts are better left on the fixed mold due to the shape constraints of the part. In order to remove the plastic part from the mold, a demoulding mechanism must be installed on the fixed mold side.