Material trapped at the product bottom (flash residue)

During the injection '2079851475616104457 production process, the product exhibits the quality defect of "Material trapped at the product bottom (flash residue)". Specifically manifested as pinch-off marks or flash residue at the bottom of the product. This defect is relatively common when processing materials such as PET, PP, HDPE, and PS, and its occurrence conditions are usually related to unreasonable settings of injection pressure, parison temperature, blowing air pressure, and mold temperature. When the Material trapped at the product bottom (flash residue) 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 injection '2079851475616104457 machine, core rod, parison mold, blow mold, and transfer mechanism, as well as injection pressure, parison temperature, blowing air pressure, and mold temperature.

1. Improper pinch-off design of the blow mold. Unreasonable structural design or process layout is often the systemic root of the problem. Runner design defects causing uneven flow, unreasonable cooling water channel layout causing temperature differences, insufficient venting structures causing air entrapment, etc., are all fundamental problems that need to be solved with emphasis during the design and development stage. 2. Parison flash not completely trimmed. This factor leading to the problem reflects that certain process conditions or material properties in injection blow '2079851475616104453ing have not met the optimal molding requirements. Such problems often have cumulative and hidden characteristics, and should be investigated and verified as key focus items during process debugging and finalization to ensure that hidden dangers are eliminated from the source. In addition, insufficient overall coordination between 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 various process parameters, and the deviation of any single parameter may aggravate the degree of Material trapped at the product bottom (flash residue) through chain effects. In terms of equipment maintenance, inadequate regular overhaul and accuracy confirmation of the injection '2079851475616104457 machine, core rod, parison mold, blow mold, and transfer mechanism cause the actual operating parameters of the equipment to deviate from the process requirements, which can also become a potential inducement of the Material trapped at the product bottom (flash residue) problem.

1. Optimize the pinch-off design. 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. Adjust the edge trimming process. 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 Material trapped at the product bottom (flash residue) problem, incorporate parison wall thickness uniformity and transfer temperature 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, HDPE, and PS should be strictly controlled to ensure the stability of molding quality from the source.

In summary, the causes of the "Material trapped at the product bottom (flash residue)" problem can be attributed to the combined action of multiple factors such as improper pinch-off design of the blow mold and parison flash not completely trimmed. Solving this problem requires starting from aspects such as optimize the pinch-off design and adjust the edge trimming process, 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 parison wall thickness uniformity and transfer temperature control.