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: The molding cycle directly affects labor productivity and equipment utilization.
Therefore, in the production process, the relevant time in the molding cycle should be shortened as much as possible under the premise of ensuring quality. In the entire molding cycle, the injection time and cooling time are the most important, and they have a decisive influence on the quality of the product.
The filling time in the injection time is directly inversely proportional to the filling rate. The filling time in production is generally about 3-5 seconds. The holding time in the injection time is the pressure time of the plastic in the mold cavity, which accounts for a large proportion of the entire injection time, generally about 20-120 seconds (special thick parts can be up to 5~10 minutes). Before the molten material is frozen at the gate, the amount of holding time has an impact on the dimensional accuracy of the product. If it is later, there is no effect.
The holding time also has a most favorable value. It is known that it depends on the material temperature, mold temperature, and the size of the main channel and gate. If the size of the main channel and gate and the process conditions are normal, the pressure value with the smallest fluctuation range of the product shrinkage rate is usually used as the standard. The cooling time is mainly determined by the thickness of the product, the thermal and crystal properties of the plastic, and the mold temperature.
The end point of the cooling time should be based on the principle of ensuring that the product does not cause changes when demolding. The cooling time is generally between 30 and 120 seconds. It is unnecessary to have a cooling time that is too long, which will not only reduce production efficiency, but also cause demolding difficulties for complex parts, and even produce demolding stress when forced demolding.
The other time in the molding cycle is related to whether the production process is continuous and automated, as well as the degree of continuity and automation.
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