Development of plastic molds

The various tools and products we use in daily production and life, ranging from the base of machine tools and body shells to as small as a cup head screw, button and the shell of various household appliances, are all closely related to molds. 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 the materials, appearances, specifications and uses of various products are different, molds are divided into non-plastic molds such as casting molds, forging molds, die-casting molds, and stamping molds, as well as plastic molds.

In recent years, with the rapid development of the plastics industry and the continuous improvement in strength and precision of general and engineering plastics, the application scope of plastic products has also been expanding, such as: household appliances, instruments and meters, construction equipment, automobile industry, In many fields such as daily hardware, the proportion of plastic products is increasing rapidly. A well-designed plastic part can often replace multiple traditional metal parts. There is a growing trend towards the plasticization of industrial and daily products.

meaning

General definition of mold: In industrial production, various presses and special tools mounted on the press are used to make parts or products of the desired shape from metal or non-metallic materials through pressure. Such special tools are collectively called molds.

Injection molding process description: A mold is a tool for producing plastic products. It consists of several groups of parts with a mold cavity inside. During injection molding, the mold is clamped on the injection molding machine. The molten plastic is injected into the mold cavity and cooled and shaped in the cavity. Then the upper and lower molds are separated. The product is ejected from the mold cavity and away from the mold through the ejection system. Finally, the mold is closed again. For the next injection molding, the entire injection molding process is carried out in a cycle.

Classification

A． Injection molding mold - TV casing, keyboard buttons, electronic product exteriors, computer peripheral plastic products, toys, household products (most commonly used)

B. Blowing mold-beverage bottle

C. Compression molding mold - Bakelite switches, scientific porcelain dishes

D． Transfer molding mold - integrated circuit products

E. Extrusion mold - glue tube, plastic bag

F. Thermoforming Mold - Transparent Forming Packaging Shell

G. Rotational mold - soft plastic doll toys

According to the different types of pouring systems, molds can be divided into three categories:

(1) Large nozzle mold: The runners and gates are on the parting line and are demoulded together with the product when opening the mold. It has the simplest design, is easy to process, and has low cost. Therefore, more people use the large nozzle system to operate.

(2) Slim nozzle mold: The runner and gate 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 complex and the processing is difficult. Generally, the selection depends on the product requirements. Fine nozzle system.

(3) Hot runner mold: The structure of this type of mold is roughly the same as that of the fine nozzle. The biggest difference is that the runner is located in one or more hot runner plates and hot spouts with constant temperature. There is no cold material demoulding, runner and pouring. The port is directly on the product, so the runner does not need to be demoulded. This system is also called a no-port system, which can save raw materials. It is suitable for situations where raw materials are expensive, product requirements are high, design and processing are difficult, and mold costs are high.