Research On Dynamic Characteristics Of Anti-Vibration Milling Cutter Based On Milling Chatter Suppression Mechanism

Milling is one of the important components of mechanical manufacturing technology,and has been widely used in aerospace,medical,automotive and military fields.With the continuous development of modern processing technology,higher requirements are placed on metal removal rate,processing efficiency,machining accuracy and surface quality,especially in the process of milling deep cavity thin-walled complex parts.The chatter problem has become an important factor restricting its development.Based on the damping and dynamic vibration absorption technology in the milling chatter suppression mechanism,this paper designs a large length-to-diameter ratio and large overhang damping dynamic anti-vibration milling cutter.Through the methods of theoretical model research,simulation analysis and experimental verification,the vibration resistance of the antivibration milling cutter is verified from the aspects of the chatter stability of the machine tooltool-workpiece system,cutting force,vibration signal and surface topography.The main research work of the thesis is as follows:(1)Based on the damping and dynamic vibration absorption theory,the two-degree-offreedom dynamic model of the damping dynamic anti-vibration milling cutter is established,and the optimal frequency ratio and the optimal damping ratio in the theoretical model are deduced.According to the theoretical model,the internal structure of the damping dynamic anti-vibration milling cutter is designed.The first 6 modes and the corresponding natural frequencies of the normal solid milling cutter,the hollow rod milling cutter and the damping dynamic anti-vibration milling cutter are obtained through modal simulation analysis.The multi-flexible body dynamics simulation of common solid milling cutter,hollow rod milling cutter and damping dynamic antivibration milling cutter is carried out.The results show that the resonance amplitude of damping dynamic anti-vibration milling cutter is reduced by 58.4% and 51.2% respectively compared with common solid milling cutter and hollow rod milling cutter.The influence and variation law of the internal structure of the damping dynamic anti-vibration milling cutter on the anti-vibration effect are further explored.(2)The modal parameters and frequency response curves of the machine tool-tool system under resonance are obtained by modal tests on various damping fluid viscosity anti-vibration milling cutters,hollow rod milling cutter and ordinary solid milling cutter.Compared with the data obtained by modal simulation,the maximum error of natural frequency is 2.6%.At the same time,the results show that the anti-vibration milling cutter with a damping fluid viscosity of 100,000 centistoke has the minimum resonance amplitude and the best anti-vibration performance under the same milling conditions.(3)The chatter stability simulation and analysis of the ordinary solid milling cutter and the damping dynamic anti-vibration milling cutter are carried out.The results show that the axial limit cutting depth of the damping dynamic anti-vibration milling cutter is increased by about 66.7% compared with the stability curve of ordinary solid milling cutter,and the whole stable cutting area is greatly increased.The maximum cutting depth of the damping dynamic antivibration milling cutter under the high-speed milling condition is also obviously increased.(4)Through the milling comparison experiment on different material parts,the analysis is carried out from the three aspects of cutting force,vibration and surface topography.The results show that the directional cutting force and the resultant cutting force of the damping dynamic anti-vibration milling cutter are smaller than the ordinary milling cutter during the milling process.The time-domain acceleration peak of the damping dynamic anti-vibration milling cutter is about 42.3% lower than that of the ordinary milling cutter in processing the AISI P20.Further analysis in frequency domain shows that the vibration amplitude of the damping dynamic anti-vibration milling cutter is reduced by 35.3% compared with the ordinary milling cutter at the chatter frequency.Compared with the ordinary milling cutter,the vibration pattern of the damping dynamic anti-vibration milling cutter has some improvement,indicating that the damping dynamic anti-vibration milling cutter has good chatter suppression effect,further indicating that the theoretical model of the damping dynamic anti-vibration milling cutter constructed in this paper is accurate,and the designed anti-vibration milling cutter has reasonable structure and good engineering application value.