Class A: moulds with complex structures such as multiple row positions, multiple parting, core-pulling and rotating core-pulling.
Class B: there are many (2 ~ 4) row oblique top 2 to 3 times parting and pumping core and other mold structure is more complex.
Class C: simple water inlet into the plastic mold, with one or two row, the general structure of the top mold.
Level D: large nozzle mold, two plate mold, no line, no inclined roof and other simple structure of the mold.
