1. Tool Selection: Prioritize carbide-coated threading tools. Use 60° pointed forming tools for external threads and matching internal threading tools for corresponding internal holes. Control the tool tip radius to R0.1~0.2mm to prevent tool breakage during cutting. Grinding parameters are set as follows: rake angle 5°~10°, clearance angle 6°~8°, and inclination angle 0°.
2. Workpiece Clamping: Use a three-jaw self-centering chuck or a four-jaw single-action chuck for external threading. For slender shafts, a follower post should be added to suppress vibration. Use soft jaws or expansion sleeves for internal threading, ensuring coaxiality ≤0.02mm to prevent workpiece deformation.
3. Machine Tool Confirmation: Check the CNC lathe spindle rotation accuracy and feed system backlash. Confirm compatibility with thread machining cycle commands (G32 single-stroke thread cutting, G92 single cycle, G76 compound cycle). Prioritize the G76 cycle for mass production.
4. Tool Setting and Coordinate System Setup: For external thread tool setting, the outer diameter datum and the Z-axis workpiece zero point must be accurately set. For internal thread tool setting, the inner hole datum and the Z-axis zero point are used as references. An edge finder, dial indicator, or tool compensation function can be used to establish the coordinate system.
5. Programming: Write the machining program based on the thread pitch, tooth profile height, and machining length. Define the cutting parameters for roughing and finishing. For example, for the G76 cycle, the P (tooth height, tool tip angle, finishing passes) and Q (minimum depth of cut) parameters need to be set.