Boring Bar Mode Shape Coupled Self-excited Vibration

The machined surface quality is an important part of evaluating machining quality. It greatly affects machine parts' usage performance, such as wear resistance, fatigue resistance, corrosion resistance, combining quality and so on. Thus ensuring parts' surface quality is an important mission during the machining process. Actually, the vibration of cutting process is one of the greatest factors, which seriously destroy the surface quality. So, the vibration of cutting process must be controlled for guaranteeing the surface quality.Boring is a commonly used cutting measure, which is used during finish machining or half finish machining. In order to controlling the vibration in the boring process and guaranteeing the surface quality, the method of adjusting the boring bar's different azimuth stiffness ratio which is based on oscillation mode coupling is adopted for the sack of reducing vibration, and a new type of boring bar with holes is presented. The boring bar is simple and economical, and particularly used for vibration reduction. According to the effecting on the vibration from the azimuths of strong and weak stiffness spindles, only keep the weak stiffness spindle away from the instability area which between cutting force direction and the normal direction of cutting surface, the anti-vibration of the system can be improved, cutting chatter is accordingly restrained.On the basis of last paragraph's theory, this paper has finished particular studies on the boring bar with holes about its vibration reduction configuration, and the boring bar's vibration reduction performance is verified by experimentation, the specific contents are as follows: 1) The significance of this subject's proposal are discussed, the application about oscillation mode coupling mechanism and the research on restraining the cutting chatter during the boring process at home and abroad are systematically and comprehensively expatiated. 2) The principium of oscillation mode coupling is introduced and its stability is analyzed, then the methods of controlling self-excited vibration is particularly discussed, and the measures of reducing the boring bar's chatter are summarized. 3) The SolidWorks mode of the boring bar is set up, the stiffness of the mode is calculated by finite element analysis of COSMOSWorks. Then the construction of the boring bar with holes is designed considering the factors which can influence the boring bar's stiffness. 4) The designed boring bar with holes is used for vibration reduction experiment, and the vibration data are disposed. The different influencing effects during the boring process caused by different diameters of the boring bar's holes are compared, so the diameter bound is given in which the boring bar has the best vibration resistance. In the end, the research results and the deficiency of this paper are summarized, and the further research work is prospected.