The criticality of melt temperature control in the production of PC desk lamp base injection molding accessories

The importance of melt temperature control
The melt temperature refers to the temperature at which the plastic raw material is heated in the barrel of the injection molding machine to flow and be smoothly injected into the mold. For PC materials, accurate control of this temperature range is crucial. Too high a melt temperature can cause thermal degradation of the material, resulting in bubbles, discoloration, and decreased mechanical properties; while too low a melt temperature may lead to insufficient material fluidity, resulting in quality problems such as insufficient filling and surface defects of the injection molded parts. Therefore, reasonable control of the melt temperature is a key step in ensuring the quality of PC desk lamp base injection molding accessories.

Control the residence time of the melt in the material pipe
The residence time of the polymer in the material pipe, that is, the time required for the entire process from the plastic particles entering the barrel to being injected into the mold, is one of the important factors affecting the melt temperature. If the residence time is too long, the material is exposed to high temperature for a long time and is prone to thermal degradation; on the contrary, if the residence time is too short, the melt may not be fully melted, resulting in uneven temperature distribution, affecting the uniformity and performance of the injection molded parts.

In order to optimize the residence time, it is first necessary to accurately calculate and set a reasonable injection molding cycle. This includes the time allocation of each stage such as injection time, holding time, cooling time and mold opening time. By adjusting these parameters, it is possible to avoid overheating of the material while ensuring production efficiency. In addition, the adjustment of the screw speed is also crucial. Although a faster screw speed can improve production efficiency, it may shorten the effective heating time of the melt in the material tube, resulting in insufficient melt temperature; conversely, a too slow speed may prolong the residence time and increase the risk of thermal degradation. Therefore, it is necessary to set an appropriate screw speed according to the characteristics of the PC material and the specific performance of the injection molding machine to achieve the best melt residence time.

Use a suitable screw design
As the core component of the injection molding machine, the design of the screw directly affects the heating, melting and conveying process of the melt. For PC materials, a gradual compression screw is an ideal choice. The characteristic of this screw is that the melt is gradually compressed at the front end, so that the material is gradually subjected to pressure during the forward process, thereby more effectively controlling the temperature and pressure distribution of the melt. The gradual compression design can reduce the sudden pressure of the melt at the front end of the screw, avoiding local overheating and material degradation caused by excessive shear stress.

In addition, the surface treatment, aspect ratio, screw groove depth and other parameters of the screw also have a significant impact on the melting effect. For example, a smooth surface can reduce the friction between the melt and the screw, reduce energy consumption while maintaining the uniformity of the melt; a reasonable aspect ratio can ensure that the melt has enough heating path in the barrel to achieve an ideal melting state. Therefore, when selecting a screw, it is necessary to comprehensively consider the material properties, product requirements and compatibility of the injection molding machine to select the most suitable screw design.