How to Prevent Nozzle Leaks

1.Any a gap between the locating ring and the sprue bushing needs to be sealed off.

2.Barrel misalignment is the most common root to result in material leaking .So how do you align an injection carriage?Cardboard and film are actually better methods then sighting it by eye, but all of them are still extremely inaccurate.

Fortunately, there is a better way: Make a barrel-alignment mandrel.

Turn down a bar of steel to a diameter of 3.999 in. and add a lead-in on one end. Now drill a hole in the center, which will have a slip fit for a custom shoulder bolt with a 7/8-14 thread—or whatever thread size is in your machine’s nozzle body.

Remove the machine nozzle tip from the nozzle body and screw the mandrel onto the end.Remove any mold that may be in the machine. Loosen the carriage leveling bolts and advance the carriage until the mandrel is well inside the platen. Now adjust and tighten the carriage leveling bolts. In this way,the carriage is aligned with the center of the fixed platen within 0.0005 in., a minimum of 20 times more accurate than the way you are doing it now.