The motion of the NC turntable is driven by the servo motor, which drives the worm gear pair to rotate the worktable after being decelerated by the gear. In order to eliminate the reverse clearance and transmission clearance, the backlash of gear mesh is eliminated by adjusting the eccentric ring. The gear on one side is connected with the worm by a wedge-shaped taut cylindrical pin, which can eliminate the fit clearance between the shaft and the sleeve. Worm gears and worms often adopt double pitch gradually thickened worm, and the clearance is adjusted by moving the axial position of the worm. The left and right sides of the worm have different pitches, so the tooth thickness of the worm gradually increases from beginning to end. However, since the pitches on the same side are the same, normal engagement can still be maintained. The worm eccentric shaft sleeve adjusts the center moment to eliminate the worm pair clearance.

When the NC turntable table is stationary, it is locked. At present, there are two locking methods: mouse tooth disc locking: it is only used on small and medium-sized NC turntables, and the locking force is small. Hydraulic locking: a ring hydraulic cylinder presses the clutch plate to clamp the worktable. It is characterized by large locking force and is used on large CNC turntable.

The CNC turntable is equipped with zero point. When it returns to zero point, the impact block installed on the worm gear first collides with the limit switch to slow down the turntable, and the turntable accurately stops at zero point through the induction block and contactless switch.

NC turntables are becoming more and more popular. With the development of the machining industry, the design of complex and multi curved parts is becoming more and more bold. More turntables are needed to provide multi axis machining. Of course, the use of true four axis and five axis machine tools will also be popularized.