Features
①Strict tolerance， 112 dimensions within ±0.05, accounting for 75% of the total dimensions 。
②The type repair is difficult, a large number of inserts required 。
③ Sufficient water cooling should be designed. Heat exchange tubes are required at some narrow space 。
④ The diameter tolerances of the column are strictly required. Ejection Angle is not allowed. The column is prone to stick to the mold and easily scratched. Only a multi-layer insertion method can be adopted for correspondence