Regular ripples on the preform surface (injection elastic instability)

In the stretch '2079851475616104457 production process, the product exhibits the quality defect of "Regular ripples on the preform surface (injection elastic instability)".The specific manifestation is Regular ripples appear on the preform surface.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 Regular ripples on the preform surface (injection elastic instability) 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. High-speed injection triggering elastic unstable melt flow.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 Regular ripples on the preform surface (injection elastic instability) through chain effects.

1. Reduce the injection speed.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. Raise the melt temperature.When implementing adjustments, it is recommended to use the single-factor variable method, adjusting only one parameter at a time and fully evaluating the effect, to avoid simultaneous changes of multiple parameters making the cause of the problem untraceable.The adjustment amplitude should be small rather than large; each adjustment is recommended to be controlled within 5%~10% of the original value, and after adjustment run stably for at least 3~5 mold cycles to observe the effect. 3. Adopt multi-stage injection.Before introducing new tools, new materials or new methods, sufficient applicability evaluation and small-batch verification should be carried out.It is recommended to first conduct offline tests or simulation analyses outside production conditions, and introduce them into the formal production line only after confirming effectiveness and safety.Keep proper change management records to facilitate subsequent traceability and experience accumulation. 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 "Regular ripples on the preform surface (injection elastic instability)" problem can be attributed to the combined action of multiple factors such as High-speed injection triggering elastic unstable melt flow.To solve this problem, it is necessary to start from aspects such as Reduce the injection speed, Raise the melt 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.