Research On The Human Like Tapping Technology Based On The Back And Forth Strategy

Threaded connection is widely used in all aspects of manufacturing due to its advantages of convenient connection and high reliability.For the processing of small-diameter internal threads with a diameter of 3 mm or less,due to the small diameter of the tap core,low strength,and poor cutting conditions,manual tapping is still mainly used in actual production.There are problems such as low processing efficiency and unstable thread quality,and it is difficult to adapt to the trend of the manufacturing automation and intelligence era.The manual tapping flexible tapping method can effectively reduce the tapping torque,and has good adaptability to different tapping conditions.Therefore,the study of manual tapping methods is essential for the development of small-diameter internal thread machining methods.In this paper,by analyzing the force of the tap during the tapping process,a tapping torque model is established,and the mechanism of tapping torque reduction is studied in conjunction with the characteristics of manual tapping motion.An anthropomorphic tapping movement strategy based on the reciprocating advance and retreat mechanism was developed,and on this basis,a anthropomorphic tapping tool holder was developed for experimental research,which provides a new method for solving small-diameter tapping automation problems.The source and composition of the torque experienced by the tap during the tapping process are analyzed.The tapping cutting torque model is established based on the trapezoidal groove shear model,and the friction torque model is established based on the Coulomb friction theory,and the variation rule of the chip resistance torque with the tapping process is analyzed.Combined with the movement characteristics of manual tapping,the mechanism of manual tapping reciprocating tapping and retraction is analyzed to reduce the tapping torque mechanism,and the tapping torque model and the reciprocating tapping and retraction mechanism are verified by the tapping test for reducing tapping.The influence of torque.Based on the analysis of the manual tapping strategy,combined with the tapping and torque reduction mechanism,a humanoid tapping strategy was established.A reciprocating tapping motion strategy based on fixed angle retraction is proposed and the retraction interval angle and reciprocating tapping angle are calculated.The humanoid tapping strategy based on torque threshold and the humanoid tapping strategy based on threshold and empirical knowledge are established,and the key parameters of the tapping strategy are determined.The principle of humanoid tapping is analyzed,and the design scheme of the tapping tool holder and the principle of torque detection are determined.The taper shank connecting taper shank,the tapping spindle and the elastic shaft of the torque detection part,and the code wheel are designed.The system error of torque detection is analyzed.The main influencing factors are the manufacturing error and installation error of the code disc,and the corresponding error compensation principle is proposed.The functions of each part of the system and the human tapping measurement and control circuit are designed,the measurement method and measurement error of the torque signal are analyzed,and the torque measurement and error compensation programs are developed.Completed the Lab VIEW host computer torque acquisition,processing,and acquisition/control interaction function design.A tool holder performance testing platform was built,and the torque detection performance of the designed tapping tool holder was studied through static and dynamic tests.The torque measurement accuracy is 2%,the resolution is 0.1 N·m,and the sensitivity is 0.724°/N·m.The experiment researched the variation law of tapping torque,thread precision and tap breakage rate under three humanoid tapping strategies.The results show that the established humanoid tapping motion strategy can effectively avoid the tap breakage,the thread quality is better,the processing efficiency is higher,and automatic tapping of small diameter internal threads can be achieved.