Precision injection molding can ensure that the products have high precision and high repeatability in terms of size and weight. The injection molding machine adopting this technology can realize high-pressure and high-speed injection. Because its control method is usually open-loop or closed-loop control, it can achieve high-precision control of injection molding process parameters. Generally, precision injection molding requires high precision of the mold. At present, small and medium-sized precision injection molding machines can be produced in China.
Rapid prototyping technology is rapidly developed with the diversification of home appliance varieties and continuous upgrades. It is mainly used to prepare plastic housings for home appliances. The advantage of this technology is that it does not require molds to achieve small batch production of plastic parts. At present, the more mature rapid prototyping methods are laser scanning molding and liquid photocuring molding, of which laser scanning molding method is widely used. The laser scanning equipment is composed of a laser light source, a scanning device, a dusting device and a computer. The processing process is that the laser head controlled by the computer scans according to a certain trajectory. At the position where the laser passes, the plastic micropowder is heated and melted and bonded together. Each time the scanning is completed, the micropowder device spreads a thin layer of powder. After repeated scanning, a product with a certain shape and size is formed.
Fused core injection technology is usually used to form special-shaped cavity products that require high cavity roughness and precision and cannot be processed by hollow molding or rotary molding. At present, the application of this technology in foreign countries is relatively mature, but it is still in a state of individual application in China. The processing principle of this technology is that the core that forms the cavity is molded first, and then the core is used as an insert for injection molding. Under the heating effect of the injection molded part, the core shape is melted and flows out, thereby forming a cavity. The most important point of using this technology is to master the melting point of core materials and plastic parts. Generally, the core material can be selected from general plastics, thermoplastic elastomers, or low melting point metals such as lead and tin, depending on the specific situation.
Gas-assisted/water-assisted injection molding has a wide range of applications. It can mold various types of injection parts. Its typical product is a TV casing. During injection molding, gas or superheated water can be injected into the cavity almost simultaneously with the plastic melt. At this time, the plastic melt coats the gas or superheated water, and the formed plastic product has a sandwich structure. After the plastic part is shaped, the mold can be released by discharging the gas or water. Such products have the advantages of material saving, small shrinkage, good appearance and good rigidity. The key part of the molding equipment is the gas-assisted or water-assisted device and its control software.
Electromagnetic dynamic injection molding technology This technology uses electromagnetic force to make the screw reciprocate in the axial direction. Since the plastic can be micro-plasticized 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 product is reduced. This technology can be used to form products with higher requirements such as optical discs. When used in the molding of ordinary products, it can improve the quality of products.
Lamination injection molding technology When using this technology, it is necessary to sandwich a special printed decorative plastic film in the mold before injection molding, and then injection molding. The printed film can be attached to the surface of the plastic parts after being deformed by heat, which is not only beautiful and firm, but also eliminates the post-decoration step.
In general, the demand for plastic molds for household appliances plastic products is very large. For example, a refrigerator or a fully automatic washing machine usually requires more than 100 plastic molds, an air conditioner requires more than 20 sets, and a color TV. The machine needs 50-70 pairs of plastic molds. At the same time, the technical requirements for plastic molds are relatively high, often requiring mold processing cycles to be as short as possible, thereby greatly promoting the development of mold design and modern mold manufacturing technology. In addition, the application of some difficult molds such as hot runner injection molds and laminated injection molds in China is gradually increasing