Determination of Nozzle Contraction Size in Casting Injection
In casting injection, especially in the mold filling process, the final product quality and operational efficiency are closely related to nozzle contraction size determination. Generally speaking, nozzle contraction size is the difference between nozzle head size and inner hole shape. This means that the nozzle contraction size needs to be precisely controlled in order to ensure accurate filling of molten metal in the casting process and to achieve optimal product quality and performance.
Before determining the size of the nozzle contraction, a few significant factors should be considered. First of all, the size of the nozzle contraction is directly related to the flow behavior of the molten metal. In other words, the size of the nozzle contraction has a direct impact on the levelling, entrainment and wetting of the molten metal. Secondly, the size of the nozzle contraction is also related to the molten metal temperature. Generally speaking, a higher molten metal temperature means higher flow speed, which enables a smaller nozzle contraction size. Last but not least, the size of the nozzle contraction needs to take into account the cooling rate and the rigidity of the laminates.
Because the size of the nozzle contraction has a direct impact on the quality and performance of the casting product, it is important to select a suitable size for the nozzle contraction in order to ensure the accurate filling of the molten metal. Generally speaking, the penetration and levelling of the molten metal should be taken into consideration when determining the size of the nozzle contraction. If the penetration of molten metal is insufficient, a larger nozzle contraction size can be adopted. On the contrary, if the levelling is poor, a smaller nozzle contraction size should be used.
Apart from the above-mentioned factors, the size of the nozzle contraction also needs to be determined based on the cooling rate and rigidity of the laminates. Generally speaking, if the cooling rate is too high or if the laminates are too rigid, a larger size of nozzle contraction should be adopted. On the contrary, if the cooling rate is too low or if the laminates are too soft, a smaller size of nozzle contraction should be used.
Furthermore, the size of the nozzle contraction also needs to be adjusted based on the corresponding injection speed. Generally, the injection speed should be checked and adjusted when the nozzle contraction size is larger than the inner hole size. When the nozzle contraction size is smaller than the inner hole size, the injection speed should be lowered accordingly.
In conclusion, nozzle contraction size determination is an important aspect of the casting process. In order to ensure precision casting, the size of the nozzle contraction needs to be selected carefully according to the penetration and levelling of molten metal, the molten metal temperature, the cooling rate, the rigidity of the laminates, and the corresponding injection speed. With precise nozzle contraction size determination, good quality casting products can be achieved.
