The Research On The Cause Of Vibration In Deep Hole Drilling And The Methods Of Vibration Reduction

In deep hole drilling, free vibration is generated by the machine itselfor through the ground, and forced vibration caused by the imbalance, as wellas the frequent strong chatter between the workpiece and the deep hole drilling.The first two kinds of vibration will be able to find the necessary solutionsand eliminated in the trial stage, but for the chatter it is difficult to findother way except for reducing metal removal rate. The processing quality ofchatter, tool and machine life are reduced by the chatter. so the research ofchatter is practical and significant. ER fluid is a controllable fluid whichcan realize the changes of rheological properties. In an applied electric field,the viscosity, yield stress and shear modulus increase sharply withinmilliseconds. Removed the applied electric field, the fluid can recover to theoriginal state instantly. so it has a potential application in vibration control.For the chatter problem in deep hole drilling, we propose to suppress thechatter by using the ER fluid. First, analyzing the vibration of deep holedrilling process and the causes of chatter, we find regenerative chatter isproved to be the most important mechanism of self-excited vibration. We researchthe dynamic model of deep-hole drilling process and obtain the differentialequations of motion and the formula of dynamic drilling force when chatter occurs.Second, analyzing the mechanism of ER and the principle of ERF damper, we designa damper used in deep hole machine, study the theory model, and get the dynamicmodel and dynamic equation. Finally the dynamic equation is simulated by Simulink components of Matlab, the simulation shows that the ERF damper takes good effect.Third, monitoring the vibration of drilling process of the horizontal deep holemachine Z8016 by 3YD34 piezoelectric accelerometer components for the vibrationmonitoring system, collecting the signal of a steady drilling, the occurrenceof chatter and vibration of the machine which was installed damper. Comparedthree types of signals, the results show that the damper has a good effect onthe chatter.