The definition of precision injection molds is determined according to two indicators, one is the precision of the processing equipment, and the other is the error caused by the mold processing. The comprehensive level of an injection molding machine is determined by the weight error of the injection molding machine. The error is less than 0.5% for the precision injection molding machine, the error is less than 0.3% for the ultra-precision machine, and the machine with the error of about 1% is the ordinary injection molding machine. As of the current state of the art, the world’s most precise injection molding machine can achieve an error of less than 0.15%.