Precision cavity piece refers to the complex shape of the inner cavity of special products, usually blind hole, using mechanical machining methods can not meet the requirements, or can not be processed. Representative products for the clutch wheels, car steering input shaft splines blind hole covers. Jiufeng firm grasp of complex precision machining mold cavity extrusion production process to ensure the accuracy of mold making. Also mastered the hollow cavity precision parts in a multi-factor condition when the size of the mass dispersion control technology to ensure that products meet the technical requirements.