The main process characteristics of precision injection molding are high injection pressure, fast injection speed and accurate temperature control.
(1) The injection pressure is high. The injection pressure used for ordinary injection is generally 40 ~ 150MPa, and it should be increased to 180 ~ 250Mpa for precision injection. In some special cases, the requirements are even higher.
(2) Fast injection speed in injection molding, if a faster injection speed is adopted, it can not only form plastic parts with complex shapes, but also reduce the dimensional tolerance of plastic parts. Therefore, when precision injection molding plastic parts, fast injection speed must be adopted.
(3) Temperature control precision temperature has a great impact on the quality of plastic parts. For precision injection, there is not only the problem of temperature, but also the problem of temperature control precision. In the process of precision injection molding, if the temperature is not accurately controlled, the fluidity of plastic melt, molding performance and shrinkage of plastic parts will be unstable, so the precision of plastic parts can not be guaranteed. Therefore, during precision injection molding, the temperature range of barrel and nozzle or injection mold must be strictly controlled.
Material selection and process requirements for precision injection molding for household appliances:
In general, the demand of household electrical appliance plastic products for Dalian injection molding plastic molds and flame-retardant plastics is very large. The most used are flame-retardant PP and flame-retardant ABS, followed by flame-retardant PBT and other flame-retardant materials. For some plastic parts of household appliances with high precision requirements, precision injection molding process is usually used.
Influencing factors of precision injection molding process:
Precision injection molding needs to consider the two most basic elements: injection equipment accuracy and injection mold accuracy.
(1) The precision of injection molding equipment is difficult to compare due to different size and product thickness, which represents the comprehensive level of injection molding machine (generally, the weight repetition error is less than 0.5%, reaching the precision level). Therefore, first-class mold processing equipment is a necessary condition for precision injection molding.
(2) Mold accuracy, mold accuracy in addition to the experience of engineers and technicians, it also needs to be completed by high-precision mold processing equipment.
In addition, it is also necessary to consider the shrinkage of plastics for household appliances, the shape and size of products for household appliances, and the shape and size of plastic parts.
Dalian injection molding
