Plastic Injection molding, also known as injection moulding, is a main molding method of thermoplastic products.
Principle of injection molding
Principle of injection molding is granular or powder plastic injection machine from hopper to the heating cylinder, through heating molten plasticizing become sticky flow, melt in the high pressure piston or screw injection machine, driven by a lot of velocity of flow through the nozzle into the mold cavity, after certain time pressure, cooling stereotypes can keep the shape of the mold cavity has given, and then open mold parting molding plastic parts.
The time required to complete an injection molding process is called the molding cycle, also known as the molding cycle.It actually consists of the following parts:
1. Molding cycle: molding cycle directly affects the rate of labor and equipment utilization.Therefore, in the production process should ensure the quality of the premise, as far as possible to shorten the molding cycle of each relevant time.
2. In the whole molding cycle, injection time and cooling time are the most important, which have a decisive influence on the quality of products.The mold filling time in the injection time is directly inversely proportional to the mold filling rate. The mold filling time in the production is generally about 3 ~ 5 seconds.The pressure holding time in the injection time is the pressure time of the plastic in the mold cavity, which accounts for a larger proportion in the whole injection time, generally about 20 ~ 120 seconds.
3. The cooling time mainly depends on the thickness of the product, the thermal and crystalline properties of the plastic, and the mold temperature.The end point of the cooling time should be based on the principle that the product will not change when it is unmoulded. The cooling time is generally about 30 ~ 120 seconds.