Bulging in the middle of the bottle body

In the stretch '2079851475616104457 production process, the product exhibits the quality defect of "Bulging in the middle of the bottle body". The specific manifestation is that abnormal bulging appears in the middle of the bottle body. This defect is relatively common when processing materials such as PET, PP, PC, and its occurrence conditions are usually related to the unreasonable settings of stretching temperature, stretch ratio, blowing pressure, and preform heating uniformity. When the "Bulging in the middle of the bottle body" situation is severe, it will cause a series of chain quality defects in the product in terms of appearance, dimensional accuracy, mechanical properties, etc., which not only reduces the functionality and safety of the product in use, but also directly increases the scrap rate and production cost. Therefore, this problem requires systematic diagnosis and optimization from multiple dimensions such as material selection, the status of the stretch '2079851475616104457 machine, heating oven, stretch rod, and blow mold, and stretching temperature, stretch ratio, blowing pressure, and preform heating uniformity.

1. Middle temperature too high. Temperature is the core factor affecting melt fluidity and viscosity. A temperature set too high will cause the melt viscosity to decrease, insufficient melt strength, and even thermal degradation; a temperature that is too low results in poor melt fluidity and insufficient plasticization, making it impossible to fill or form smoothly. A reasonable temperature window should be optimized and determined within the recommended range according to the melting characteristics and thermal stability of the material. 2. Blowing pressure too high. Pressure directly determines the filling ability of the melt during the forming process and the effect of conforming to the mold. Insufficient pressure results in incomplete filling and poor replication accuracy; excessive pressure may cause secondary defects such as flash and excessive internal stress. The pressure setting should comprehensively consider factors such as material viscosity, product dimensions, and mold structure. In addition, the insufficient overall coordination of preform heating uniformity and biaxial stretch orientation control is also a factor that cannot be ignored; there are complex interactions and coupling relationships among the process parameters, and the deviation of any one parameter may aggravate the degree of "Bulging in the middle of the bottle body" through chain effects. In terms of equipment maintenance, the regular overhaul and precision confirmation of the stretch '2079851475616104457 machine, heating oven, stretch rod, and blow mold are not in place, causing the actual operating parameters of the equipment to deviate from the process requirements, which will also become a potential inducement of the "Bulging in the middle of the bottle body" problem.

1. Optimize the heating curve to lower the middle temperature. Adjustments should follow the principle of gradual progress; the amplitude of each adjustment should not be too large, and it is recommended to decrease by 5%~15% of the current value. After each adjustment, observe the product quality changes stably for at least 5~10 mold cycles, and continue adjusting only after confirming that the improvement direction is correct; avoid one-step excessive adjustment. 2. Adjust the blowing pressure. Optimization work must be based on an accurate diagnosis of the root cause of the problem, and blind attempts must be avoided. It is recommended to first determine the key influencing factors and their interactions through the process DOE test method or historical production data analysis, and then carry out parameter optimization and structural improvement in a targeted manner to achieve twice the result with half the effort. It is recommended to formulate a preventive checklist for the "Bulging in the middle of the bottle body" problem, incorporate preform heating uniformity and biaxial stretch orientation control into the daily inspection scope, and conduct online monitoring of key parameters through the SPC statistical process control method to achieve early warning and rapid response to the problem. In terms of material management, incoming inspection of raw materials upon arrival and in-process inspection of work-in-progress should be strengthened, and the key performance indicators of PET, PP, PC should be strictly controlled to ensure the stability of molding quality from the source.

In summary, the causes of the "Bulging in the middle of the bottle body" problem can be attributed to the combined action of multiple factors such as Middle temperature too high, Blowing pressure too high. Solving this problem requires starting from aspects such as Optimize the heating curve to lower the middle temperature, Adjust the blowing pressure and adopting systematic governance measures. In actual production, it is recommended to establish a prevention and rapid response mechanism for this problem, and achieve stable production and continuous improvement through preform heating uniformity and biaxial stretch orientation control.