Inside attached drawing mill spherical spherical inside the treatment on milling machine principle and treatment spherical outside surface are identical. Workpiece draws fine line, installation is in milling machine dividing head inside 3 ungual chuck, or go up in circumgyrate workbench with installation of workpiece of bolt, pressing plate general. The central line of the central line that spies arbor and workpiece is inside a plane, next establish milling head to pull an angle A, if attached drawing place is shown. Adjust knife head to rotate radius R, make the whirl of point of a knife radius is equal to E/2, with computation leaving type: In E=Rcosa2 type: E -- point of a knife rotates radius (Mm) ; R -- spherical radius (Mm) ; A -- the point of view that milling head turns (° ) . When milling, point of a knife must pass spherical center, cutting tool with cutting speed 150 ～ 200m/min high speed rotates, workpiece also rotates with rotate speed of 5 ～ 10r/min, but mill goes out inside spherical. CNC Milling