Cold crystallization of the preform during storage

In the stretch '2079851475616104457 production process, the product exhibits the quality defect of "Cold crystallization of the preform during storage".The specific manifestation is The preform crystallizes after long-term low-temperature storage.This defect is more common when processing materials such as PET, PP and PC, and its occurrence is usually related to unreasonable settings of stretching temperature, stretch ratio, blowing pressure and preform heating uniformity.When the Cold crystallization of the preform during storage situation is severe, it will cause a series of chain quality defects in the product's appearance, dimensional accuracy, mechanical properties and other aspects, which not only reduces the product's functionality and safety 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. PET undergoes cold crystallization when staying in the 80-120°C range for a long time.This factor causing the problem reflects that certain process conditions or material properties in stretch '2079851475616104457 do not meet the optimal forming requirements.Such problems are often cumulative and concealed, and should be investigated and verified as key focus items during process debugging and finalization to ensure hidden dangers are eliminated at the source. 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 parameter may aggravate the degree of Cold crystallization of the preform during storage through chain effects.

1. Avoid long-term storage of preforms in the crystallization temperature range.The storage conditions of materials and products directly affect their processing adaptability and use performance.The temperature, humidity and lighting conditions of the storage environment should be controlled according to material characteristics, avoiding high-temperature high-humidity and direct sunlight areas.For hygroscopic materials, sealed moisture-proof packaging or dry environment storage should be adopted. 2. Control the storage temperature.The key to process parameter control lies in establishing a reliable closed-loop feedback adjustment mechanism.Timely discover deviation trends through online real-time detection and SPC statistical process monitoring, and use automatic control systems or manual intervention to maintain key parameters within the set window, achieving a fundamental shift from after-the-fact remediation to prior prevention. It is recommended to formulate a preventive checklist for the Cold crystallization of the preform during storage 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 problems. In terms of material management, incoming inspection of raw materials and in-process testing of work-in-progress should be strengthened, and key performance indicators of PET, PP and PC should be strictly controlled to ensure the stability of forming quality from the source.

In summary, the causes of the "Cold crystallization of the preform during storage" problem can be attributed to the combined action of multiple factors such as PET undergoes cold crystallization when staying in the 80-120°C range for a long time.To solve this problem, it is necessary to start from aspects such as Avoid long-term storage of preforms in the crystallization temperature range, Control the storage temperature and take 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 preform heating uniformity and biaxial stretch orientation control.