In industrial production, a variety of presses and special tools installed on the press are used to make metal or non-metallic materials into parts or products of the required shape through pressure. Such special tools are collectively called molds. The various tools and products used in our daily production and life, ranging from the base of the machine tool and the body shell, as small as a embryo head screw, button and the shell of various household appliances, are all closely related to the mold. The shape of the mold determines the appearance of these products, and the processing quality and precision of the mold also determines the quality of these products. Because of the different materials, appearance, specifications and uses of various products, they can be divided into plastic molds and non-plastic molds:
(1) Non-plastic molds include: casting molds, forging molds, stamping molds, die-casting molds, etc.
A. Casting mold-faucet, pig iron platform
B. Forging die-car body
C. Stamping die-computer panel
D. Die casting mould-super alloy, cylinder block
(2) Plastic molds are divided into different production processes and products:
A. Injection molding mold-TV shell, keyboard buttons (most commonly used)
B. Blow mold-beverage bottle
C. Compression molding mold-bakelite switch, scientific porcelain dishes
D. Transfer molding mold-integrated circuit products
E. Extrusion mould-glue pipe, plastic bag
F. Thermoforming mold-transparent molded packaging shell
G. Rotary forming mold-soft doll toy
In recent years, with the rapid development of the plastics 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, instrumentation, construction equipment, automobile industry, Japan In many fields such as hardware, the proportion of plastic products is increasing rapidly. A reasonably designed plastic part can often replace multiple traditional metal parts. The trend of plasticization of industrial products and daily-use products is on the rise.
A mold is a tool for producing plastic products. It is composed of several groups of parts, and there is a molding cavity in this combination. During injection molding, the mold is clamped on the injection molding machine, the molten plastic is injected into the molding cavity, cooled and shaped in the cavity, and then the upper and lower molds are separated, and the product is ejected from the cavity and out of the mold through the ejection system, and finally the mold is closed For the next injection, the entire injection molding process is carried out in cycles. On the mold line, it is demolded together with the product when the mold is opened. The design is the simplest, easy to process, and low cost, so more people use the large nozzle system to work. Nozzle mold: runners and gates are not on the parting line, usually directly on the product, so it is necessary to design an additional set of nozzle parting lines, the design is more complicated, and the processing is more difficult. Generally, the nozzle system should be selected according to the product requirements . Hot runner mold: The structure of this type of mold is roughly the same as the nozzle. The biggest difference is that the runner is in one or more hot runner plates and hot nozzles with constant temperature. There is no cold material demoulding, and the runner and gate are directly in As for the product, the runner does not need to be demolded. This system is also known as a nozzleless system, which can save raw materials and is suitable for situations where raw materials are more expensive and products require higher requirements. Design and processing are difficult, and mold costs are higher.