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  • Direct (sprue) gate
Direct (sprue) gate

Direct (sprue) gate

  • Models No:VA001
  • Products material:ABS
  • Gate:Edge gate
  • Mold Construction:Two Plate mold
  • Product description: Direct (sprue) gate

Part No:TV remote control device

Cavity No:1x1

Ejection:Ejector pin



A 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.

  • A smaller taper angle (a minimum of one degree) risks not releasing the sprue from the sprue bushing on ejection.
  • A larger taper wastes material and extends cooling time.
  • Non-standard sprue tapers will be more expensive, with little gain.