Improper proportion of regrind used

During the extrusion '2079851475616104457 production process, the product exhibits the quality defect of "Improper proportion of regrind used". Specifically manifested as an excessively high regrind proportion causing a decline in product strength or poor appearance. This defect is relatively common when processing materials such as HDPE, PP, PVC, and PC, and its occurrence conditions are usually related to unreasonable settings of melt temperature, extrusion speed, blowing air pressure, and mold temperature. When the Improper proportion of regrind used 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 extruder, die head, die, mold clamping mechanism, and blowing system, as well as melt temperature, extrusion speed, blowing air pressure, and mold temperature.

1. Severe degradation of the regrind. Under the action of high temperature and shear, the resin undergoes thermal degradation, oxidative degradation, and mechanochemical degradation, leading to molecular chain scission, reduced molecular weight, and deterioration of mechanical properties. Controlling the processing temperature within a safe window, shortening the melt thermal history time, and adding appropriate heat stabilizers and antioxidants are effective means to suppress degradation. 2. Proportion not strictly controlled. This factor leading to the problem reflects that certain process conditions or material properties in extrusion 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. In addition, insufficient overall coordination between parison wall thickness control and parison temperature uniformity is also a factor that cannot be ignored; there are complex interactions and coupling relationships among the various process parameters, and the deviation of any single parameter may aggravate the degree of Improper proportion of regrind used through chain effects. In terms of equipment maintenance, inadequate regular overhaul and accuracy confirmation of the extruder, die head, die, mold clamping mechanism, and blowing system cause the actual operating parameters of the equipment to deviate from the process requirements, which can also become a potential inducement of the Improper proportion of regrind used problem.

1. Limit the regrind proportion within a reasonable range (generally ≤20%). The adjustment of formulations and ratios should determine the plan on the basis of laboratory small-scale tests, and then be verified by on-line pilot tests. Any change in the formulation should be recorded and its impact on all aspects of product performance evaluated. Automatic metering and batching devices can effectively reduce errors and batch-to-batch fluctuations of manual batching. 2. Sort and dry the regrind. 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. It is recommended to formulate a preventive checklist for the Improper proportion of regrind used problem, incorporate parison wall thickness control and parison temperature uniformity into the scope of daily inspections, and conduct online monitoring of key parameters through the SPC statistical process control method to achieve early warning and rapid response to problems. 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 HDPE, PP, PVC, and PC should be strictly controlled to ensure the stability of molding quality from the source.

In summary, the causes of the "Improper proportion of regrind used" problem can be attributed to the combined action of multiple factors such as severe degradation of the regrind and proportion not strictly controlled. Solving this problem requires starting from aspects such as limit the regrind proportion within a reasonable range (generally ≤20%) and sort and dry the regrind, 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 control and parison temperature uniformity.