Crack propagation at the preform gate

In the stretch '2079851475616104457 production process, the product exhibits the quality defect of "Crack propagation at the preform gate".The specific manifestation is Micro-cracks at the preform gate propagate during stretching causing rupture.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 Crack propagation at the preform gate 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. Large residual stress at the gate.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. 2. Unreasonable gate design.Unreasonable structural design or process layout is often the systematic root of the problem.Runner design defects causing uneven flow, unreasonable cooling water channel layout causing temperature differences, insufficient venting structure causing trapped air, etc., are all fundamental problems that need to be solved with emphasis in the design and development stage. 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 Crack propagation at the preform gate through chain effects. In terms of equipment maintenance, the regular overhaul and accuracy 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 process requirements, which will also become a potential inducement of the Crack propagation at the preform gate problem.

1. Optimize gate design.Optimization work must be based on accurate diagnosis of the root cause of the problem; blind attempts must be avoided.It is recommended to first determine the key influencing factors and their interactions through process DOE test methods or historical production data analysis, and then carry out targeted parameter optimization and structural improvement to achieve twice the result with half the effort. 2. Reduce residual stress at the gate.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. 3. Improve demolding.Optimization work must be based on accurate diagnosis of the root cause of the problem; blind attempts must be avoided.It is recommended to first determine the key influencing factors and their interactions through process DOE test methods or historical production data analysis, and then carry out targeted parameter optimization and structural improvement to achieve twice the result with half the effort. 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 "Crack propagation at the preform gate" problem can be attributed to the combined action of multiple factors such as Large residual stress at the gate, Unreasonable gate design.To solve this problem, it is necessary to start from aspects such as Optimize gate design, Reduce residual stress at the gate 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.