Bottle body ovality out of tolerance

In the stretch '2079851475616104457 production process, the product exhibits the quality defect of "Bottle body ovality out of tolerance". The specific manifestation is that the cross-section of the bottle body is not round. 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 ovality 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. Poor blow mold precision. 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. 2. 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 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 "Bottle body ovality out of tolerance" 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 "Bottle body ovality out of tolerance" problem.

1. Repair the cavity precision. Polishing operations should be carried out step by step from coarse to fine; each time a finer abrasive is changed, the polishing direction should be changed to eliminate the texture traces of the previous step. The final surface roughness should be tested with a roughness meter to confirm it meets the standard. After polishing is completed, it should be thoroughly cleaned to remove abrasive and grinding agent residues to prevent them from entering the melt and contaminating the product. 2. Optimize the cooling symmetry. 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 "Bottle body ovality out of tolerance" 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 "Bottle body ovality out of tolerance" problem can be attributed to the combined action of multiple factors such as Poor blow mold precision, Uneven cooling. Solving this problem requires starting from aspects such as Repair the cavity precision, Optimize the cooling symmetry 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.