Plastic raw materials, which are usually in a solid or elastomeric state at normal room temperature, are heated during the plastic injection molding process so that they will change from solid plastic into a molten liquid with mobility in order to facilitate shaping in the subsequent injection molding into finished product. What requires special attention during the process of injection molding of plastics is how dry the plastic raw materials are. if a raw material with moisture is driven into the high temperature barrel, it is very likely to jeopardize the stability of the process of injection molding, and may even affect the appearance and property of the molded product.

Of the many common raw materials in this industry like PP, PA, PE, PC and ABS, some actually contain a small amount of moisture on their surface and require drying separately, for example, PA and PC. Thus, it is necessary to verify what plastic materials being used before production and ensure the dryness of the materials before proceeding with the injection process.

Operator’s skills are crucial to the process of plastic injection molding. The so-called operational skills are actually the setup of controlling injection parameters and the adjustments made at any time. We divide the range of plastic injection parameters to be adjusted into the following five categories: "Temperature", "Pressure", "Speed", "Position", and "Time". Of these, temperature is more particular than the others; it covers the drying temperature, injection barrel heating temperature, mold cooling temperature, etc. to be adjusted, while the other parameters are set and fine-tuned, when appropriate, according to the steps of plastic injection and the injection condition of each product. In the past, skilled operators tended to rely on their feelings or experience in adjusting the machine; however, as technology advances, on today’s injection molding machines, adjustments of parameters can be made based on the data that are transmitted in real time.