Injection machines usually need to be readjusted after replacing new materials. This is because different plastic materials have different physical and chemical properties, such as melting temperature, flowability, viscosity, thermal stability, cooling rate, and shrinkage rate, which directly affect the process parameters during injection molding. If the setting parameters of the old materials continue to be used, it is likely to result in incomplete mold filling, defects on the surface of the product, increased dimensional deviation, and even material degradation or injection system blockage. Therefore, after replacing the new material, the operator needs to reset and optimize the parameters of the injection molding machine, such as temperature, injection pressure, injection speed, holding time, cooling time, etc., based on the characteristics of the new material to ensure the stability of the molding quality and the improvement of production efficiency. In addition, if materials with significant color differences are replaced, it may be necessary to clean the barrel and screw to prevent color contamination or mixing issues. In short, conducting necessary process adjustments and equipment inspections after each material change is an important step in ensuring the smooth progress of injection molding production.