The Sprue portion of the runner can be eliminated by fitting this unit in place of the sprue bush of a mold.

Aim of this unit

The sprue portion of the runner wastes raw materials and obstructs resin flow, reducing molding quality, increasing stress, and making the injection pressure excessive. Also, the sprue takes longer to cool than products do, making the molding cycle longer than necessary.

Eliminating the sprue halves the bulk of the runner, so production costs for transportation and storage are also halved.


  • 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.


  • 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.

Figure of hot sprue bush mounted on a mold


  • Suits all resins
  • The sprue bush is so tough it will outlast several generations of molds.
  • The valveless sealing mechanism prevents stringing completely.

Standard specifications

Spec. \ Type HS-60 HS-70 HS-90 HL-100 HL-120
A dimension 60mm 70mm 90mm 100mm 120mm
B dimension ø40mm ø45mm
C dimension 24mm 32mm
D dimension 10mm 25mm
E dimension 10mm 15mm
F dimension 2.0 (specified)
G dimension 52mm 62mm 82mm 92mm 112mm
Heater capacity 220V/160W 220V/250W
Thermocouple C.A. or I.C.
  • The heater and thermocouple are assembled.
  • Special specification are acceptable for A and G dimensions. (Ask for prices)
  • Ask about custom designs.
  • Thermo-controller (proportional type) is available as option.