Sprue Bush

The sprue bush is the connecting member between the machine nozzle and the mold face, and provides suitable aperture through which the material can travel on its way to the mould cavity or the start of the runner system in multi-impression molds.There are two basic design of sprue bush which differ only with respect to the form of seating between the sprue bush and nozzle of the machine:

• The first of these is a sprue bush with a spherical recess which is used in conjunction with a spherical front ended nozzle.
  
• The second has a flat rear face, used with a corresponding nozzle.
  

The internal aperture of the sprue bush is tapered, which facifilitates removal of the sprue from the mold at the end of molding cycle.