How does Syringe Mould prevent the mold shrinkage error?

Since the shrinkage rate will change due to the injection pressure, for a single cavity mold, the cavity pressure in the cavity should be as consistent as possible. As for the multi-cavity mold, the cavity pressure between the cavities should be very small. In the case of single cavity with multiple gates or multiple cavity with multiple gates, injection must be made with the same injection pressure to make the cavity pressure consistent. For this reason, it is necessary to ensure that the gate positions are balanced. In order to make the cavity pressure consistent in the cavity, the pressure at the gate entrance should be consistent. The pressure balance at the gate is related to the flow resistance in the runner. Therefore, before the gate pressure reaches equilibrium, the runner should be balanced.

Because the melt temperature and mold temperature have an impact on the actual shrinkage rate, when designing a precision injection mold cavity, in order to facilitate the determination of the molding conditions, attention must be paid to the cavity arrangement. Because the molten plastic brings heat into the mold, and the temperature gradient distribution of the mold generally surrounds the cavity, which is in the shape of concentric circles with the main runner as the center.

Therefore, design measures such as runner balance, cavity arrangement and concentric arrangement centered on the sprue are necessary to reduce the shrinkage error between the cavities, expand the allowable range of molding conditions, and reduce costs. . The cavity arrangement of the precision syringe mold should meet the requirements of the balance of the runner and the arrangement with the main runner as the center, and the cavity arrangement with the main runner as the line of symmetry must be adopted.

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