Basic knowledge and technical application of plastic mold

The plastic processing industry is equipped with plastic molding machines, which endow plastic products with complete configuration and accurate dimensions.
Due to the wide variety of plastics and processing methods, and the complex and simple structure of plastic molding machines and plastic products, the types and structures of plastic molds are also diverse.
General classification of moulds: plastic moulds and non-plastic moulds:
(1) Non-plastic molds include: casting mold, forging mold, stamping mold, die-casting mold, etc.
A. Casting mold - faucet, pig iron platform
B. Forging die - automobile body
C. Stamping die - computer panel
D. Die-casting die - superalloy, cylinder block
(2) Plastic mold
According to different production processes and products, it can be divided into:
A. Injection molding mold - TV shell, keyboard button (widely used)
B. Blowing mold - beverage bottle
C. Compression molding mold - bakelite switch, scientific ceramic bowl and dish
D. Transfer molding mold - integrated circuit products
E. Extrusion molding mold - glue pipe, plastic bag
F. Thermoforming mold - transparent molding packaging shell
G. Rotary molding mold - soft rubber doll toy
Technical application of plastic mold products
A combined plastic mold for compression molding, extrusion molding, injection molding, blow molding and low foaming molding, which mainly comprises a concave mold with a variable cavity composed of a concave mold composite substrate, a concave mold component and a concave mold composite clamp, and a convex mold with a variable core composed of a convex mold composite substrate, a convex mold component, a convex mold composite clamp, a cavity cutting component and a side cutting composite plate.
Coordinated change of die convex, concave and auxiliary molding system. It can process series plastic parts of different shapes and sizes.
All kinds of tools and products used in our daily production and life, ranging from the base of the machine tool and the shell of the machine body to the shell of a embryo head screw, button and the shell of various household appliances, are closely related to the mold.
The shape of the mold determines the shape of these products, and the processing quality and precision of the mold also determine the quality of these products. Because of the different materials, appearances, specifications and uses of various products, moulds are divided into casting moulds, forging moulds, die-casting moulds, stamping moulds and other non-plastic moulds, as well as plastic moulds.
1. In recent years, with the rapid development of the plastic industry and the continuous improvement of the strength and precision of general and engineering plastics, the application range of plastic products is also expanding, such as: household appliances, instruments and meters, construction equipment, automotive industry, household hardware and other fields, the proportion of plastic products is increasing rapidly. A reasonably designed plastic part can often replace many traditional metal parts.
The trend of plasticization of industrial products and household products is on the rise.
2. General definition of mould: in industrial production, metal or non-metallic materials are made into parts or products of required shape by pressure with various presses and special tools installed on the press. Such special tools are collectively referred to as moulds.
3. Injection process description: mold is a tool for producing plastic products. It is composed of several groups of parts, in which there is a molding cavity. During injection molding, the mold is clamped on the injection molding machine, the molten plastic is injected into the mold cavity, cooled and shaped in the cavity, then the upper and lower molds are separated, the products are ejected from the mold cavity through the ejection system, and the later mold is closed for the next injection molding. The whole injection process is cyclic.
4. (1) The mold line is demoulded together with the product during mold opening. The design is simple, easy to process, and the cost is low. Therefore, many people use the large water outlet system for operation.
(2) Fine nozzle mold: the runner and gate are not on the parting line, and are usually directly on the product. Therefore, it is necessary to design more sets of nozzle parting lines, which are more complex in design and difficult to process. Generally, the fine nozzle system should be selected according to the product requirements.
(3) Hot runner mold:
The structure of this type of mold is basically the same as that of the fine nozzle. The major difference is that the runner is located in one or more hot runner plates and hot pump mouths with constant temperature. There is no cold material demoulding. The runner and gate are directly on the product, so the runner does not need demoulding. This system is also called the no-nozzle system, which can save raw materials. It is applicable to the situation where the raw materials are expensive and the product requirements are high. It is difficult to design and process, and the mold cost is high.