Hot Sprue Bush

  • The sprue portion of the runner wastes raw materials and obstructs resin flow, which in turn reduces molding quality, increases stress and causes excessive injection pressure.
  • The sprue also takes longer to cool than the products do, causing the molding cycle to be longer than necessary.
  • Eliminating the sprue halves the bulk of the runner, so production costs for transportation and storage are also halved.
  • The MSK Hot Sprue Bush replaces the sprue bush of a mold and is able to provide a smoother injection molding process.


  • When injection is complete, a valveless sealing system closes the gate, eliminating problems such as resin drooling and stringing. (Patent pending)
  • We made the heating wire of the tubular heater last several times longer than that of an ordinary heater.
  • The outer diameter of the hot sprue bush is only ø24 or ø32mm (standard) including the heater, so the mold stays rigid.
Download catalogue/Spec sheet

How it will reduce your costs:

  • Product is tough enough to outlast several generations of molds.

How it will boost your efficiency and yield:

  • Suits all resins
  • Valveless sealing mechanism prevents stringing completely.

Construction of the Hot Sprue Bush:

  • A high-precision abrasive-finished tubular heater is fitted on the cylindrical part of the sprue bush main body to form a hot sprue bush.
  • The main body is made of highly heat- and pressure-resistant steel.