Abstract:Large 5 axis horizontal machining center rotary table is the component which drives workpiece rotating in the machining process, its rotation accuracy and reliability directly affect the overall performance of the machine tool. For the characteristic that B axis of the five axis machine tool moved in the cutting process, a large clearance adjustment worm gear was used to drive, the transmission mechanism was equipped with gear to increase the driving torque, the rotary mechanism was supported by large axial and radial combination bearing, a high precision grating ruler was used to feed back position. Then a high precision rotary table with fast feed speed 5 r/min, the positioning accuracy of 3″,the repeated positioning accuracy of 1.5″ is gotten.