Stress cracking of the product after long-term use

In the injection '2079851475616104457 production process, the product exhibits the quality defect of "Stress cracking of the product after long-term use".The specific manifestation is Cracks appear on the product surface after several months of use.This defect is more common when processing materials such as PET, PP, HDPE and PS, and its occurrence is usually related to unreasonable settings of injection pressure, parison temperature, blowing pressure and mold temperature.When the Stress cracking of the product after long-term use 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 injection '2079851475616104457 machine, core rod, parison mold, blow mold and transfer mechanism, and injection pressure, parison temperature, blowing pressure and mold temperature.

1. Long-term action of residual stress.This factor causing the problem reflects that certain process conditions or material properties in injection '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. 2. Environmental factors accelerate aging.Resin undergoes thermal degradation, oxidative degradation and mechanochemical degradation under high temperature and shear, leading to molecular chain scission, reduced molecular weight and deteriorated mechanical properties.Controlling processing temperature within the safe window, shortening melt heat history time and adding appropriate heat stabilizers and antioxidants are effective means to inhibit degradation. In addition, the insufficient overall coordination of parison wall thickness uniformity and transfer temperature 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 Stress cracking of the product after long-term use through chain effects. In terms of equipment maintenance, the regular overhaul and accuracy confirmation of the injection '2079851475616104457 machine, core rod, parison mold, blow mold and transfer mechanism are not in place, causing the actual operating parameters of the equipment to deviate from process requirements, which will also become a potential inducement of the Stress cracking of the product after long-term use problem.

1. Optimize the process to reduce residual stress.Adjustments should follow the principle of gradual progress; each adjustment should not be too large, and a decrement of 5%~15% of the current value is recommended.After each adjustment, stably observe the product quality changes for at least 5~10 mold cycles, and continue adjusting only after confirming the improvement direction is correct; never make excessive one-step adjustments. 2. Add antioxidants and stabilizers.Formula and ratio adjustments should be determined on the basis of laboratory small-scale tests, and then verified by on-line pilot tests.Any change to the formula should be recorded and its impact on all aspects of product performance evaluated.Automatic metering and batching devices can effectively reduce manual batching errors and batch-to-batch fluctuations. It is recommended to formulate a preventive checklist for the Stress cracking of the product after long-term use problem, incorporate parison wall thickness uniformity and transfer temperature 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, HDPE and PS should be strictly controlled to ensure the stability of forming quality from the source.

In summary, the causes of the "Stress cracking of the product after long-term use" problem can be attributed to the combined action of multiple factors such as Long-term action of residual stress, Environmental factors accelerate aging.To solve this problem, it is necessary to start from aspects such as Optimize the process to reduce residual stress, Add antioxidants and stabilizers 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 parison wall thickness uniformity and transfer temperature control.