The molding and processing methods of household plastic […]
The molding and processing methods of household plastic products mainly include injection molding, extrusion molding, thermoforming, hollow molding, lamination molding, compression molding, transfer molding, foam plastic molding, casting molding, insert casting, sealing casting, etc. Mainly injection molding.
In recent years, some new plastic processing technologies and new equipment have been widely used in the molding of home appliance plastic products, such as precision injection molding, rapid prototyping technology, melt core injection technology, gas assisted / water assisted injection molding technology, electromagnetic dynamic injection molding technology and coating Film injection molding technology.
Can guarantee the product in terms of size and weight with high precision and high repeatability. The injection molding machine using this technology can achieve high pressure and high speed injection. Because its control mode is usually open-loop or closed-loop control, it can achieve high-precision control of injection molding process parameters.
Generally, precision injection requires higher precision in the mold. At present, China has been able to produce small and medium-sized precision injection molding machines.
2. Rapid Prototyping Technology
It is developed rapidly along with the diversification of home appliance varieties and continuous upgrading, and is mainly used to prepare plastic housings for home appliances. The advantage of this technology is that small batches of plastic parts can be achieved without the need for a mold.
At present, the more mature rapid prototyping methods include laser scanning molding and liquid light curing molding. Among them, laser scanning molding method is widely used. The laser scanning device is composed of a laser light source, a scanning device, a dusting device and a computer. The processing process is that the computer-controlled laser head scans according to a certain trajectory. At the position where the laser passes, the plastic micropowder is heated and melted and bonded together. After each scan, the micropowder device sprinkles a thin powder. After repeated scanning, products with a certain shape and size are formed.
At present, some domestic enterprises can produce laser scanning molding machines and plastic powders, but the performance of the equipment is unstable, and the types of powders are also small.
3. Melt core injection technology
It is usually used to form special-shaped cavity products with high requirements on cavity roughness and accuracy, which cannot be processed by hollow forming or rotary forming methods.
At present, the application of this technology in foreign countries has been relatively mature, but it is still in an individual application state in China. The processing principle of this technology is that the core shape that forms the cavity is formed first, and then the core shape is used as an insert for injection molding.
Under the heating effect of the injection molded part, the core is melted and flowed out, thereby forming a cavity. The most important point to use this technology is to know the melting point of core materials and plastic parts. Generally, the core material can be selected from general-purpose plastics, thermoplastic elastomers or low-melting-point metals such as lead, tin, and the like according to specific conditions.