Uneven preform wall thickness

During the stretch '2079851475616104457 production process, the product exhibits the quality defect of "Uneven preform wall thickness". Specifically manifested as large differences in the axial or circumferential wall thickness of the preform. This defect is relatively common when processing materials such as PET, PP, and PC, and its occurrence conditions are usually related to unreasonable settings of stretching temperature, stretch ratio, blowing air pressure, and preform heating uniformity. When the Uneven preform wall thickness situation is severe, it will cause a series of chain-reaction quality defects in the product in terms of appearance, dimensional accuracy, mechanical properties, etc., which not only reduces the usability and safety of the product, but also directly increases the scrap rate and production cost. Therefore, this problem requires systematic diagnosis and optimization from multiple dimensions, including material selection, the condition of the stretch '2079851475616104457 machine, heating oven, stretch rod, and blow mold, as well as stretching temperature, stretch ratio, blowing air pressure, and preform heating uniformity.

1. Uneven gap between the core rod and the cavity. Uniformity runs through every stage of the '2079851475616104453. Uneven temperature, uneven pressure distribution, uneven cooling, uneven material mixing, etc. will all lead to dispersion in product quality. Ensuring the uniform distribution of all physical quantities is a prerequisite for obtaining products with good consistency and stable quality. 2. Uneven injection pressure distribution. Pressure directly determines the filling ability of the melt and the mold-contacting effect during the '2079851475616104453. Insufficient pressure results in incomplete filling and poor replication accuracy; excessive pressure may cause secondary defects such as flash and excessive internal stress. The setting of pressure should comprehensively consider factors such as material viscosity, product dimensions, and mold structure. In addition, insufficient overall coordination between 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 various process parameters, and the deviation of any single parameter may aggravate the degree of uneven preform wall thickness through chain effects. In terms of equipment maintenance, inadequate regular overhaul and accuracy confirmation of the stretch '2079851475616104457 machine, heating oven, stretch rod, and blow mold cause the actual operating parameters of the equipment to deviate from the process requirements, which can also become a potential inducement of the Uneven preform wall thickness problem.

1. Adjust the gap between the core rod and the cavity. 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 targeted parameter optimization and structural improvement to achieve twice the result with half the effort. 2. Optimize the injection pressure and holding pressure. 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 targeted parameter optimization and structural improvement to achieve twice the result with half the effort. It is recommended to formulate a preventive checklist for the Uneven preform wall thickness problem, incorporate preform heating uniformity and biaxial stretch orientation control into the scope of daily inspections, 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 inspection of work-in-progress should be strengthened, and the key performance indicators of PET, PP, and PC should be strictly controlled to ensure the stability of molding quality from the source.

In summary, the causes of the "Uneven preform wall thickness" problem can be attributed to the combined action of multiple factors such as uneven gap between the core rod and the cavity and uneven injection pressure distribution. Solving this problem requires starting from aspects such as adjust the gap between the core rod and the cavity and optimize the injection pressure and holding pressure, and adopting 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.