## 1 Introduction  
The traditional injection molding manufacturing process is still the mainstream processing method in the plastics industry due to its low processing cost, fast production speed, large production volume, and formable products with complex shapes. The molding principle is to plasticize plastic pellet particles, transforming the raw materials into a molten state by the action of external heat and the sheer heat generated by screw rotation. The molten polymer is injected into a pre-designed mold cavity through screw advancement and molded into the shape of the mold design. The output product quality [1] is a function of the processing conditions, melt quality, material property, mold design, and machine parameter setting; any changes in the above will deliver a defective product with short shot, flash, air bubbles, silver streaks, warpage, shrinkage, etc. In an injection molding process, factors [2] that affect the final quality of the product include the quality of the plastic pellets, the injection speed, the injection pressure, the packing pressure [3], the melt temperature, and the mold temperature. Among the many variable factors, plastic pellets determine the mechanical properties of the product [4]. Most plastics can absorb moisture from the air before production. This ability is influenced by the type of plastic material used, environmental conditions, drying temperature and time, and so on. Hygroscopic materials [5] such as polyurethane, acrylonitrile butadiene styrene, polycarbonate, and others, can absorb moisture even after drying when exposed to the atmosphere. If the plastic pellets contain moisture even after drying, the absorbed moisture will cause many difficulties in the molding and processing of the product part. Furthermore, the internal quality [6] of plastic products will significantly deteriorate, resulting in polymer degradation [7]; product quality is reflected in the appearance of silver streaks [8], scorch marks, air bubbles, and poor surface finish, and a decrease in product surface transparency [9] that can be observed with the naked eye. Consequently, the effect of moisture produces additional plastic waste in an injection molding process, affecting the sustainability of the production process. Research scholars have conducted studies to improve the surface quality. For example, [PERSON] [10] proposed a method to compensate for the influence of moisture content in plastic pellets on molded parts quality by combining the pressure controller with a switching point and feedback control of the injection pressure during the injection stage. [PERSON] and [PERSON] [11] \"investigated the morphology evolution and elimination mechanism of bubble marks on the surface of micro-cellular injection-molded parts with dynamic mold temperature control\". [PERSON] and [PERSON] [12] explored the effect of gate design on the surface finish of thin-film components according to process parameter injection pressure and injection rate. These methods help to improve the surface finish of product parts and reduce the appearance of air bubbles in the final product part. However, these studies did not determine the effect on injection molding parameters of moisture content or propose a method to regulate the generation of air bubbles in the plasticization stage in an injection molding process. The materials are affected by moisture factors, so it is necessary to use a dryer to reduce the moisture content in the material to ensure consistency in the process and product quality. However, using a traditional 50 kg drying machine with a daily power consumption of 4.5 kilowatt hours and a required drying time of 2 to 4 h before production, the accumulated power consumption is very great. In large-scale plastic molding processing plants, a larger number of dryer machines are required to cooperate with each other to maintain an uninterrupted supply of production materials.