Clogging of the blow pin (blow rod)

During the extrusion '2079851475616104457 production process, the product exhibits the quality defect of "Clogging of the blow pin (blow rod)". Specifically manifested as the blowing passage being blocked by foreign matter, resulting in unsmooth blowing. This defect is relatively common when processing materials such as HDPE, PP, PVC, and PC, and its occurrence conditions are usually related to unreasonable settings of melt temperature, extrusion speed, blowing air pressure, and mold temperature. When the Clogging of the blow pin (blow rod) 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 extruder, die head, die, mold clamping mechanism, and blowing system, as well as melt temperature, extrusion speed, blowing air pressure, and mold temperature.

1. Flash or scrap entering the blow rod hole. This factor leading to the problem reflects that certain process conditions or material properties in extrusion 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. 2. Poor filtration of the compressed air. This factor leading to the problem reflects that certain process conditions or material properties in extrusion 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 control and parison temperature uniformity 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 Clogging of the blow pin (blow rod) through chain effects. In terms of equipment maintenance, inadequate regular overhaul and accuracy confirmation of the extruder, die head, die, mold clamping mechanism, and blowing system cause the actual operating parameters of the equipment to deviate from the process requirements, which can also become a potential inducement of the Clogging of the blow pin (blow rod) problem.

1. Clean the blow rod passage. Cleaning work should be incorporated into the equipment preventive maintenance plan, and the cleaning frequency should be reasonably determined according to the actual conditions of the processed material and the operating cycle. Use dedicated cleaning tools and cleaning materials to avoid scratching the cavity surface or electrolytic corrosion caused by improper operation. After cleaning, re-check and confirm that the key clearances are accurate. 2. Install an air filter. The installation of equipment or accessories should strictly follow the installation manual; the key mating surfaces must be cleaned and checked for damage before installation. Fastening bolts should be tightened evenly according to the specified torque values and diagonal sequence; after installation, use precision measuring tools to verify whether the installation accuracy meets the technical requirements. 3. Regularly maintain the blowing system. Equipment maintenance should establish a three-level preventive maintenance system: daily spot checks, regular maintenance, and planned overhauls. The operating data and wear trends of key components should be continuously statistically analyzed, and the probability and time window of potential failures should be predicted through condition monitoring, transforming passive fault repair into active condition-based maintenance. 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 HDPE, PP, PVC, and PC should be strictly controlled to ensure the stability of molding quality from the source.

In summary, the causes of the "Clogging of the blow pin (blow rod)" problem can be attributed to the combined action of multiple factors such as flash or scrap entering the blow rod hole and poor filtration of the compressed air. Solving this problem requires starting from aspects such as clean the blow rod passage and install an air filter, 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 control and parison temperature uniformity.