A locating ring is a circular member fitted on to the front face of the mold over the sprue bush. Its purpose is to register (or locate) the mold in the correct position on the injection machine, to ensure proper alignment between the nozzle and the sprue bush, thereby eliminating leakage.
Precision surface grinding services can also be used for round rod. Although the outside diameter of the rod is not made round by surface grinding, the two ends of the rods can be precision surface ground to make them perfectly perpendicular to the outside diameter. Here, V-blocks are employed to position the rods for grinding. The round rod is placed into the V-shaped cavity, and a clamp holds the rod vertically in place. From there, precision surface grinding can be used to grind the top of the rod to a dimension that is perfectly square to the outside diameter.