Uneven bottle neck threads

During the injection '2079851475616104457 production process, the product exhibits the quality defect of "Uneven bottle neck threads". Specifically manifested as incomplete filling of the bottle neck threads or uneven thread pitch. 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 Uneven bottle neck threads 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. Insufficient venting of the thread cavity. Mold venting is a basic condition to ensure smooth filling of the melt. When venting is poor, the air in the mold cavity is compressed to form a high-pressure air cushion, which hinders melt flow and causes problems such as insufficient filling, burnt, and weld lines. A reasonable venting design should consider the venting position and venting gap to ensure that air is discharged in time. 2. Parison temperature too low. Temperature is the core factor affecting melt fluidity and viscosity. Setting the temperature too high will cause the melt viscosity to decrease, insufficient melt strength, and even thermal degradation; if the temperature is too low, the melt fluidity is poor and plasticization is insufficient, making it impossible to fill or mold smoothly. A reasonable temperature window should be optimally determined within the recommended range according to the melting characteristics and thermal stability of the material. 3. Insufficient injection pressure. 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 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 Uneven bottle neck threads problem.

1. Add thread venting structures. 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. 2. Increase the parison temperature and injection pressure. When implementing adjustments, it is recommended to adopt the single-factor variable method, adjusting only one parameter at a time and fully evaluating the effect, to avoid multiple parameters changing simultaneously making the cause of the problem untraceable. The adjustment magnitude 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. It is recommended to formulate a preventive checklist for the Uneven bottle neck threads 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 "Uneven bottle neck threads" problem can be attributed to the combined action of multiple factors such as insufficient venting of the thread cavity and parison temperature too low. Solving this problem requires starting from aspects such as add thread venting structures and increase the parison temperature and injection 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 parison wall thickness uniformity and transfer temperature control.