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Texturing/Polishing:glazeA direct (or sprue) gate is commonly used for single-cavity molds, where the sprue feeds material directly into the cavity rapidly with minimum pressure drop. The disadvantage of using this type of gate is the gate mark left on the part surface after the runner (or sprue) is trimmed off. Freeze-off is controlled by the part thickness rather than determined the gate thickness. Typically, the part shrinkage near the sprue gate will be low; shrinkage in the sprue gate will be high. This results in high tensile stresses near the gate.
The starting sprue diameter is controlled by the machine nozzle. The sprue diameter here must be about 1.0 mm larger than the nozzle exit diameter. Standard sprue bushings have a taper of 2.4 degrees, opening toward the part. Therefore, the sprue length will control the diameter of the gate where it meets the part; the diameter should be at least 1.5 mm larger than or approximately twice the thickness of the part at that point.
Contact: Edward Xie
Phone: +86 18898606708
Tel: +86 760 23127756
Add: No.92, ShengPing South Road, Suixi Industrial Zone, Nantou Town, Zhongshan City, Guangdong Province. 528427. China