Study On The Mechanism And Process Effect Of Vibratory Tapping

As an accuracy technology process for inner screw , vibratory tapping has some advantages such as reducing the tapping torque, improving the machine quality of inner screw. It has unique superiority in machining the small diameter thread, especially for difficult-to-machine material such as titanium, so has a favorable applied foreground. This paper is devoted to study on the mechanism and process effect of vibratory tapping. In this paper, the fundamental investigations and the main inaugurated harvest are showed as follows:1. This paper exploits the microcomputer control system of vibratory tapping that ameliorate the previous control system. The new control system makes the machine process go on fluently, enhances the machine efficiency and copes with factors which break out in the tapping process. The control system has some important functions, such as returning in time when tapping process failure appears, memorizing the machine process, carrying out all kinds of vibratory mode and laying down the program on-line.2. Based on investigating the trait of two vibratory modes, named the separable vibratory mode and step vibratory mode, this paper makes use of the advantages of the separable vibratory mode and step vibratory mode and puts forward the new vibratory mode, named the composed vibratory mode. Lately, in order to broaden the research zone of the vibratory tapping, this paper analyzes the movement principle, composition of process parameters, torque character, lubricated status and the chip forming mechanism of the composed vibratory tapping.3. In the field of rigidity mechanism, firstly, based on dynamic angular displacement in vibratory tapping, this paper deduces the equation of the nominal tensional rigidity of the tap in the vibratory tapping. Secondly, this paper deduces the equation of the maximum deflection angle of the tap in vibratory tapping, numerically analyzes how the net cutting time ratio and the forced angular vibratory frequency impact on the maximum deflection angle of the tap and draws some valuable conclusions which enrich the tap’s rigidity mechanism in vibratory tapping.4. In the field of experiment study of the process effect in vibratory tapping, to start with, this paper experimentally studies the result of scrap breaking and confirms the mechanism of scraps; In addition, on the basis that repeat cutting is an important character of the separable vibratory tapping and composed vibratory tapping, firstly, this paper analyzes theoretically the repeated cutting times on the surface of inner screw. Secondly, this paper theoretically and experimentally how the repeated cutting times affects the accuracy of inner Screw and puts forward the main problems which must be attentive when optimizing the repeated cutting times. This paper also studies how vibratory mode affects the accuracy of inner Screw. Finally, this paper analyzes how the process parameters, tap structure and vibratory mode affect on the life of the tap and makes sure that vibratory tapping under the composed vibratory mode not only has the machining effect of the separable vibratory tapping but also enhances the life of tap compared to the separable vibratory tapping.5. BP neural network is applied in the research of the modeling of vibratory tapping. To start with, the neural network model considering the basic process parameter is trained more times by means of a large amount of experimental data of vibratory tapping. In addition, the trained neural network model is used to simulate the tapping torque. Results of simulation on tapping torque show that if the neural network model is trained by adequate experimental data, the tapping torque of vibratory tapping using the BP neural network method can predict tapping exactly. Finally, by means of mixed programming using the VB and Mat-lab, the predictable system is established.This research is supported by the National Science Foundation of China under the project No.50675088.The content in this paper broadens the new research zone of vibratory tapping and enriches the mechanical theoretics of vibratory tapping.