To introduce to you: home appliances plastic products of six major injection molding technology

The main processing methods of plastic products for household appliances are injection molding, extrusion molding, hot molding, hollow molding, laminating molding, compression molding, transfer molding, foam plastic molding, pouring molding, embedding casting, sealing casting, etc., among which injection molding is the main.

In recent years, some new plastic processing technologies and new equipment have been widely used in the molding of household appliances plastic products, such as precision injection molding, rapid prototyping technology, core injection molding technology, gas-assisted/water-assisted injection molding technology, electromagnetic dynamic injection molding technology and coated injection molding technology.

Injection molded product

1. Precision injection molding

Can ensure the product size and weight with high precision and high repeatability. The injection molding machine with this technology can realize high pressure and high speed injection. Because the control mode is usually open or closed loop control, the injection molding process parameters can be controlled with high precision.

Generally, precision injection molding requires higher precision of the mold. At present, the domestic has been able to produce small and medium-sized precision injection molding machine.

2. Rapid prototyping technology

Is accompanied by the variety of household appliances to the diversification of the direction of development and continuous upgrading and rapid development, mainly used for the preparation of plastic housing for household appliances. The advantage of this technology is that small batch production of plastic parts can be achieved without mold.

At present, relatively mature rapid prototyping methods include laser scanning molding and liquid photocuring molding, among which laser scanning molding is widely used. Laser scanning equipment is composed of laser light source, scanning device, dusting device and computer. The processing process is, by the computer controlled laser head according to a certain track scanning, in the laser through the position, the plastic powder is heated melting and bonded together, every scanning once, the powder device is scattered with a thin layer of powder, so that after repeated scanning, the formation of a certain shape and size of the product.

Now, there are some domestic enterprises can produce laser scanning molding machines and plastic powder, but the performance of the equipment is not stable, the type of powder is less.

3. Core injection molding technology

It is usually used for molding special-shaped cavity products which require high roughness and precision of cavity and can not be processed by hollow forming or rotary forming.

At present, the application of this technology has been relatively mature in foreign countries, but it is still in the state of individual application in China. The processing principle of this technology is that the core forming the cavity is formed first, and then the core is used as the insert for injection molding.

Under the heating action of injection parts, the core melts and flows out, thus forming the cavity. The most important point to use this technology is to master the melting point of core materials and plastic parts. Usually, the core material can be selected according to the specific situation and general plastic, thermoplastic elastomer or low melting point metals such as lead, tin, etc.

4. Gas-assisted/water-assisted injection molding

Widely used, can be formed a variety of types of injection parts, the typical product is the TV shell. During injection, gas or superhot water can be injected into the cavity almost simultaneously with the plastic melt.

At this time, the plastic melt will be gas or superhot water coating, forming plastic products for sandwich structure, plastic parts after the shape of gas or water can be demoulded. Such products have the advantages of material saving, shrinking, good appearance and good rigidity. The key part of the molding equipment is the gas-assisted or water-assisted device and its control software.

In recent years, although the domestic research is more, the application speed is fast, but the domestic equipment is not stable.

5. Electromagnetic dynamic injection molding technology

The technique makes the screw vibrate in the axial direction through the action of electromagnetic force. Because the plastic can be microplasticized in the pre-plasticization stage, the structure of the plastic parts in the pressure holding stage is more dense, and the internal stress of the products is reduced.

This technique can be used to shape more demanding products such as optical discs. When it is used for forming common products, it can improve the quality of products.

6. Laminating injection molding technology

To use this technique, the special printed decorative plastic film needs to be clamped into the mold before injection molding, and then injection molding. Printing film after heat deformation can fit on the surface of plastic parts, not only beautiful and firm, but also eliminate the decorative steps.

Generally, the demand for plastic molds for plastic products of household appliances is very large. For example, the plastic molds required for a refrigerator or a fully automatic washing machine usually exceed 100 pairs, an air conditioner needs more than 20 pairs, and a color TV needs 50-70 pairs of plastic molds.

At the same time, the technical requirements of plastic molds are relatively high, and often require the processing cycle of molds to be as short as possible, which greatly promotes the development of mold design and modern mold manufacturing technology. In addition, some difficult mold such as hot runner injection mold, laminated injection mold in the domestic application is gradually increasing.