Product sink mark

During the injection '2079851475616104457 production process, the product exhibits the quality defect of "Product sink mark". Specifically manifested as local depressions appearing on the product surface. 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 Product sink mark 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 holding 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. 2. Short cooling time. Cooling conditions determine the setting process and the final internal structure of the product. Uneven cooling leads to shrinkage differences and residual stress, causing warpage and dimensional deviations; insufficient cooling makes the product not rigid enough at demolding; excessively rapid cooling generates large internal stress. The cooling system design should ensure uniform and efficient heat dissipation in all areas. 3. Large wall thickness difference. The uniformity of wall thickness distribution is directly related to the mechanical properties of the product and the consistency of cooling shrinkage. Excessive wall thickness differences will cause inconsistent cooling rates, with sink marks and warpage occurring in thick-walled areas and insufficient strength in thin-walled areas. Wall thickness design should follow the principle of uniform wall thickness, and wall thickness changes should transition smoothly. 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 Product sink mark problem.

1. Increase the holding 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. 2. Extend the cooling time. 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. 3. Reduce the wall thickness difference. Adjustments should follow the principle of gradual progress; the magnitude of each adjustment should not be too large, and it is recommended to decrease in steps of 5%~15% of the current value. After each adjustment, observe the product quality changes stably for at least 5~10 mold cycles, and continue adjusting only after confirming that the improvement direction is correct; one-step excessive adjustment must be avoided. 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 "Product sink mark" problem can be attributed to the combined action of multiple factors such as insufficient holding pressure and short cooling time. Solving this problem requires starting from aspects such as increase the holding pressure and extend the cooling time, 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.