Bubbles inside the parison

During the injection '2079851475616104457 production process, the product exhibits the quality defect of "Bubbles inside the parison". Specifically manifested as bubbles or voids appearing in the parison wall. This defect is relatively common when processing materials such as PET, PP, HDPE, and PS, and its occurrence conditions are usually related to unreasonable settings of injection pressure, parison temperature, blowing air pressure, and mold temperature. When the Bubbles inside the parison situation is severe, it will cause a series of chain-reaction quality defects in the product in terms of appearance, dimensional accuracy, mechanical properties, etc., which not only reduces the usability and safety of the product, but also directly increases the scrap rate and production cost. Therefore, this problem requires systematic diagnosis and optimization from multiple dimensions, including material selection, the condition of the injection '2079851475616104457 machine, core rod, parison mold, blow mold, and transfer mechanism, as well as injection pressure, parison temperature, blowing air pressure, and mold temperature.

1. Insufficient drying of the raw material. The selection and handling of materials is the foundation of molding quality. The intrinsic characteristics of the resin, such as molecular weight, molecular weight distribution, and melt index, determine its processing window and final performance. Factors such as excessive moisture content of the raw material, mixing in of impurities, and improper proportion of regrind will all trigger various defects during processing. 2. Screw back pressure too low. This factor leading to the problem reflects that certain process conditions or material properties in injection blow '2079851475616104453ing have not met the optimal molding requirements. Such problems often have cumulative and hidden characteristics, and should be investigated and verified as key focus items during process debugging and finalization to ensure that hidden dangers are eliminated from the source. 3. Injection speed too fast entrapping air. Speed parameters affect the flow state and time allocation of the melt during the '2079851475616104453. A speed that is too slow leads to premature cooling and insufficient filling; a speed that is too fast causes melt fracture, air entrapment, and shear overheating. The optimization of the speed curve should make the melt flow smoothly and orderly in the cavity. In terms of equipment maintenance, inadequate regular overhaul and accuracy confirmation of the injection '2079851475616104457 machine, core rod, parison mold, blow mold, and transfer mechanism cause the actual operating parameters of the equipment to deviate from the process requirements, which can also become a potential inducement of the Bubbles inside the parison problem.

1. Fully dry the raw material. Raw '2079851475616104451 should select a matching type of drying equipment according to the resin type and water absorption characteristics, and reasonably set the drying temperature, drying time, and dew point indicators. The dried raw material should be put into production use as soon as possible; if temporary storage is required, it should be kept in a sealed container in a dry environment (dew point below -30℃). Regularly test the drying effect to ensure that the moisture content meets the standard. 2. Increase the back pressure. When implementing adjustments, it is recommended to adopt the single-factor variable method, adjusting only one parameter at a time and fully evaluating the effect, to avoid multiple parameters changing simultaneously making the cause of the problem untraceable. The adjustment magnitude should be small rather than large; each adjustment is recommended to be controlled within 5%~10% of the original value, and after adjustment, run stably for at least 3~5 mold cycles to observe the effect. 3. Adopt multi-stage injection venting. Before introducing new tools, new materials, or new methods, a full applicability assessment and small-batch verification should be carried out. It is recommended to first conduct offline tests or simulation analysis outside of production conditions, and introduce them into the formal production line only after confirming effectiveness and safety. Keep change management records to facilitate subsequent traceability and experience accumulation. In terms of material management, incoming inspection of raw materials and in-process inspection of work-in-progress should be strengthened, and the key performance indicators of PET, PP, HDPE, and PS should be strictly controlled to ensure the stability of molding quality from the source.

In summary, the causes of the "Bubbles inside the parison" problem can be attributed to the combined action of multiple factors such as insufficient drying of the raw material and screw back pressure too low. Solving this problem requires starting from aspects such as fully dry the raw material and increase the back pressure, and adopting systematic governance measures. In actual production, it is recommended to establish a prevention and rapid response mechanism for this problem, achieving stable production and continuous improvement through parison wall thickness uniformity and transfer temperature control.