Bottle body perpendicularity out of tolerance

In the stretch '2079851475616104457 production process, the product exhibits the quality defect of "Bottle body perpendicularity out of tolerance". The specific manifestation is that the axis of the bottle body is not straight or is bent. 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 "Bottle body perpendicularity out of tolerance" 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. Preform eccentricity. This factor causing the problem reflects that certain process conditions or material characteristics in stretch blow '2079851475616104453ing have not met the optimal molding requirements. Such problems are often cumulative and hidden, and should be investigated and verified as key focus items during process debugging and finalization to ensure that hidden dangers are eliminated at the source. 2. Stretch rod and mold not concentric. The mold is the core tool that gives the product its shape and surface quality. Unreasonable mold design, such as improper runner/gate dimensions, insufficient venting, and inadequate draft angle, will directly cause molding defects. The machining accuracy, surface treatment quality, and daily maintenance status of the mold also directly affect product quality. 3. Uneven cooling. Cooling conditions determine the setting process of the product and its final internal structure. Uneven cooling causes shrinkage differences and residual stress, leading to warpage and dimensional deviation; insufficient cooling makes the product not rigid enough at demolding; overly rapid cooling generates large internal stress. The cooling system design should ensure uniform and efficient heat dissipation in all parts. 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 "Bottle body perpendicularity out of tolerance" problem.

1. Correct the preform concentricity. Calibration work should use standard instruments that have been verified and qualified by a legal metrological verification institution, and be carried out strictly in accordance with the prescribed cycle and method. Calibration results should form a written technical report, giving the deviation value and expanded uncertainty. Out-of-tolerance equipment should be immediately taken out of service and marked for repair, and can only be restored to use after being recalibrated and qualified. 2. Calibrate the coaxiality of the stretch rod and the mold. Calibration work should use standard instruments that have been verified and qualified by a legal metrological verification institution, and be carried out strictly in accordance with the prescribed cycle and method. Calibration results should form a written technical report, giving the deviation value and expanded uncertainty. Out-of-tolerance equipment should be immediately taken out of service and marked for repair, and can only be restored to use after being recalibrated and qualified. 3. Optimize cooling. 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. 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 "Bottle body perpendicularity out of tolerance" problem can be attributed to the combined action of multiple factors such as Preform eccentricity, Stretch rod and mold not concentric. Solving this problem requires starting from aspects such as Correct the preform concentricity, Calibrate the coaxiality of the stretch rod and the mold 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.