The time required to complete an injection molding process is called the molding cycle, also known as the molding cycle. It actually includes the following parts: molding cycle. Forming cycle directly affects labor productivity and equipment utilization. Therefore, in the production process, the plastic mold manufacturer should shorten the relevant time in the molding cycle as far as possible on the premise of ensuring the quality. In the whole molding cycle, injection time and cooling time are the most important, which have a decisive impact on the quality of products. The filling time in the injection time is directly proportional to the filling rate, and the filling time in production is generally about 3-5 seconds.
The pressure holding time in the injection time is the pressurization time of the plastic in the cavity, accounting for a large part of the injection time, generally about 20-120 seconds (the extra thick part can be as high as 5-10 seconds). Minutes). Before the molten material at the gate is frozen, the length of pressure holding time has an impact on the dimensional accuracy of the product, but if it is later, it will not. The residence time also has an optimum value, which is known to depend on the material temperature, the mold temperature, and the gate and gate size. If the size and process conditions of the gate and gate are normal, the pressure value with the smallest fluctuation range of the shrinkage rate of the product shall prevail.
The cooling time mainly depends on the thickness of the product, the thermal and crystalline properties of plastic injection molding and the mold temperature. The end of the cooling time shall be based on the principle of ensuring that the product will not change during demoulding. The cooling time is generally between 30 and 120 seconds. If the cooling time is too long, it is unnecessary, which not only reduces the production efficiency, but also affects complex parts. It is difficult to demould, and even demoulding stress will occur when forced demoulding. Other times in the forming cycle are related to whether the production process is continuously automated and the degree of continuous automation.