Numerical Analysis on the Key Technology in Extrusion Tapping of Internal Thread

This paper introduces the principle and characteristic of extrusion tapping of internal thread, presents the simplified mechanical model of extrusion tapping firstly. Then generalizes the key technology of extrusion tapping and their influencing law on tapping torque and thread forming quality, such as extrusion tap type, lead hole diameter, tapping speed and friction. Finally, numerical analysis on the key technology of extrusion tapping are conducted based on DEFORM-3D, the results show that the effect of lead hole diameter and friction on tapping torque are obvious, the effect of extrusion tap type and tapping speed on tapping torque are next and this effect degree is related to the stress-strain relation of workpiece material under different strain-rate closely. These researches will contribute to the right selection of workpiece material, extrusion tap type, lead hole diameter, tapping speed and lubrication of extrusion tapping of internal thread in practical manufacture.