Technical application of plastic mold


Everything we produce and use in our daily life, from t […]

Everything we produce and use in our daily life, from the base of the machine tool and the shell of the machine body to the shell of a screw, button and various household appliances, all have a close relationship with the mold. The shape of the mold determines the shape of these products, and the processing quality and accuracy of the mold also determines the quality of these products. Because of the different materials, appearances, standards, and uses of various products, the molds are divided into non-plastic molds such as casting molds, forging molds, die-casting molds, stamping molds, and plastic molds.
In recent years, with the rapid development of the plastics industry and the continuous improvement of strength and precision of general and engineering plastics, the scope of use of plastic products has also been expanding, such as: household appliances, instruments, construction equipment, automotive industry, In many fields such as daily hardware, the share of plastic products is rapidly increasing. A well-planned plastic part can often replace multiple traditional metal parts. The trend of plasticization of industrial and daily products is increasing.
General definition of mold: In industrial production, various presses and special things installed on the press are used to make metal or non-metal materials into parts or products of desired shapes through pressure. Such special things are collectively called molds.
Description of the injection process: A mold is something that produces plastic products. It consists of several groups of parts, and this combination has a molding cavity. During injection molding, the mold is clamped on the injection molding machine, and the molten plastic is injected into the mold cavity, cooled and shaped in the cavity, and then the upper and lower molds are separated. The product is ejected from the mold cavity through the ejection system and finally closed For the next injection, the entire injection process is cyclic.
A. Injection molding molds-TV casings, keyboard buttons, electronic products, computer peripheral plastic products, toys, household items (most widely used)
B. Blow mold-beverage bottle
C. Compression molding dies-bakelite switches, scientific porcelain dishes
D. Transfer molding die-integrated circuit products
E. Kneading mold-glue tube, plastic bag
F. Thermoforming mold-transparent molding packaging shell
G. Rotary forming mold-soft plastic doll toy
According to the different casting system types, the molds can be divided into three categories:
(1) Large gate nozzle: The runner and gate are on the parting line, and the product is demolded together with the product when the mold is opened. The simplest planning, easy processing, and low cost, so more people use the large gate system.
(2) Spout mold: the runner and gate are not on the parting line, and are usually directly on the product, so an additional set of spout parting lines should be planned. The planning is more complicated and the processing is more difficult. Generally, it should be selected according to product requirements The spout system.
(3) Warm runner mold: The structure of this type of mold is roughly the same as that of the spout. The biggest difference is that the runner is located in one or more warm runner plates and hot nozzles with constant temperature. The nozzle is directly on the product, so the flow channel does not need to be demoulded. This system is also called the nozzleless system, which can save raw materials. It is suitable for the situation where the raw materials are expensive and the product is required.
The warm runner system, also known as the hot runner system, is mainly composed of a hot gate sleeve, a hot runner plate, and a temperature-controlled electric box. Our common warm runner system has two methods: single-point hot gate and multi-point hot gate. Single-point hot gate is to use a single hot-gate sleeve to inject molten plastic directly into the cavity. It is suitable for plastic molds with single-cavity and single-gate; It can be used in single-cavity multi-point feeding or multi-cavity mold.

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