Unstable product weight

During the extrusion '2079851475616104457 production process, the product exhibits the quality defect of "Unstable product weight". Specifically manifested as large weight fluctuations among products of the same batch. 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 Unstable product weight 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. Fluctuation of parison length or wall thickness. The uniformity of wall thickness distribution is directly related to the mechanical properties of the product and the consistency of cooling shrinkage. Excessive wall thickness differences will cause inconsistent cooling rates, with sink marks and warpage occurring in thick-walled areas and insufficient strength in thin-walled areas. Wall thickness design should follow the principle of uniform wall thickness, and wall thickness changes should transition smoothly. 2. Variation in raw material density. 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. 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 Unstable product weight 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 Unstable product weight problem.

1. Stabilize the wall thickness control system. The key to process parameter control lies in establishing a reliable closed-loop feedback adjustment mechanism. Through online real-time detection and SPC statistical process monitoring, deviation trends are discovered in time, and automatic control systems or manual intervention are used to maintain key parameters within the set window, achieving a fundamental transformation from after-the-fact remediation to prior prevention. 2. Regularly calibrate the weighing. Inspection work should establish a standardized inspection checklist, clarifying the inspection items, technical standards, inspection frequency, and responsible persons. Key equipment components should be regularly disassembled to inspect the condition of hidden parts, and judgment should not be based solely on operating appearance. Inspection results should be recorded in detail and a trend analysis mechanism established to predict potential failures. 3. Control raw material batch consistency. The key to process parameter control lies in establishing a reliable closed-loop feedback adjustment mechanism. Through online real-time detection and SPC statistical process monitoring, deviation trends are discovered in time, and automatic control systems or manual intervention are used to maintain key parameters within the set window, achieving a fundamental transformation from after-the-fact remediation to prior prevention. 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 "Unstable product weight" problem can be attributed to the combined action of multiple factors such as fluctuation of parison length or wall thickness and variation in raw material density. Solving this problem requires starting from aspects such as stabilize the wall thickness control system and regularly calibrate the weighing, 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.