Papers by Keyword: Extrusion Tapping

Abstract: This paper firstly introduces the principle and characteristic of traditional extrusion tapping of internal thread, elaborates the material flow law during tapping process. Then puts forward a novel process of vibration-assisted extrusion tapping of internal thread, explains the effect mechanism of vibration during extrusion tapping of internal thread. Finally, with the finite element method (FEM), the simplified model of extrusion tapping are built, and the simulation of thread forming process of traditional extrusion tapping of internal thread are conducted, furthermore, the characteristic and influencing law of different vibration parameters (include vibration frequency, amplitude and direction) of vibration-assisted extrusion tapping of internal thread are studied, and some practical results are obtained. The simulation results show that applying vibration to extrusion tapping of internal thread can reduce tapping torque and improve thread forming quality, the reasonable selection of vibration parameters are very crucial to this novel process.

Abstract: 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.

Abstract: Extrusion tapping is a novel and important processing method of internal thread, carrying out research on the thread forming process can contribute to a better application of this process in more industrial situation. The principle of extrusion tapping of internal thread is introduced in this paper firstly, and then the simplified finite element model of extrusion tapping and the thread forming simulation is conducted. Next, the thread forming process and metal plastic flow law during extrusion tapping of internal thread are analyzed based on the simulation. Finally, the revised formulas for calculating extrusion deformation area and volume are presented and comparison are made with the referenced formulas, the results show that the revised formulas can express the practical extrusion deformation area and volume more correctly. Furthermore, the similar law between the revised extrusion deformation volume and extrusion force obtained from simulation are proved effectively.

Abstract: Internal thread processing is an indispensable procedure in manufacture, its processing efficiency and quality become more and more important in modern manufacturing, especially in aerospace and automotive industry. Compared with the traditional process of cut tapping of internal thread, the process of extrusion tapping of internal thread possesses the following advantages: without chip, higher precision, better surface quality, better continuity of metallic, greater efficient, greater strength, longer tool life. This paper firstly introduces the current research status of extrusion tapping of internal thread, elaborates the principle and characteristic of extrusion tapping, analyzes the matal plastic flow law and thread forming characteristic during tapping, then generalizes the influencing law of the key technology on thread forming quality, such as extrusion tap type, lead hole diameter, tapping speed and friction. Furthermore, puts forward some improvement approach to reduce tapping torque and enhance forming quality of internal thread.