The inner spiral groove of the circular connector part is usually used for quick screw connection. Generally, there are three spiral grooves uniformly distributed around the circumference, so that when the fast screw connection is connected, the circumferential force is uniform and the screwing is light. For the machining of the triple spiral grooves of the inner holes of the circular connector parts (usually called "thread sleeves"), a special spiral groove milling machine is usually used to mill and shape. The processing method is that the workpiece is clamped on the chuck of the machine tool spindle, and the small milling cutter is installed on the power head of the machine tool slide; During processing, the spindle rotates at a uniform speed, and the slide plate feeds at a uniform speed, and the rotating small milling cutter mills a spiral groove on the workpiece; Then the carriage retreats in the X and Z directions successively, and after retreating to the reference position, the machine tool spindle rotates by 120 degrees. After the rotation reaches the point, the spindle rotates at an even speed, and the slide plate feeds at an even speed, and the rotating small milling cutter mills and processes a second spiral groove on the workpiece; Repeat the above steps to complete the processing of three spiral grooves. The control of the above-mentioned process is realized through the numerical control system. When small batch production, the inner hole triple spiral groove of the screw sleeve can also be processed by a high-end CNC turning and milling center. Use a high-end 5-axis CNC turning and milling center to machine the inner hole triple spiral groove. There are two traditional methods, one is to use the attached power head for milling, the mechanism is the same as the special spiral groove milling machine; The other is to use the indexing function of the spindle to process the groove. Both of these methods are inseparable from the indexing function of the spindle, and the equipment used for processing is high-end expensive equipment.