Mechanism And Experimental Study Of BTA Deep Hole Drilling

With the continuous development of machining technology, deep hole processing technology is no longer limited to the military field, but widely used in aerospace, high-speed railway, automotive, energy mining and other fields. It plays an important role in the processing manufacturing industry. Because of the closed nature of the deep hole processing, is not easy to measure instantaneous temperature and the force of the cutting tool in the process of processing. The machining quality of deep hole, can not directly observed, the processing condition can be judged only by observing the vibration of the drill pipe or the shape of the chip. This paper studies BTA deep hole drilling by using simulation and processing experiment based on the deep hole drilling mechanism.Firstly, this paper explaines the principle of metal cutting, analyzes the chip formation process and describes the deformation degree of chip, with introduced the BTA deep hole machining system in detail. Through the comparison of the characteristics of BTA multi-tooth drilling with BTA single tooth drilling characteristics, the advantages of BTA multi-tooth drilling are discovered. The forces of the BTA multi-tooth drilling are analyzed. Then the mathematical model of the deep-hole BTA drilling process are established. The formula of the total axial force and torque are obtained by calculation.Secondly, the BTA drilling process is simulated by using DEFORM finite element software. The instantaneous temperature of each cutter tooth is obtained by observing the chip morphology of three cutter teeth. The influence of the rotating velocity and feed rate on the cutting temperature is studied. Then the torque and axial force are analyzed, the influence of cutting parameters on it is studied.Finally, based the deep hole drilling test on EMU axle of EA4 T motor train unit, according to previous processing experience and the characteristics of EA4 T steel, a reasonable processing technology is determined. Different rotating speed or feed rate are applied to process. The optimal cutting parameters are obtained by observing the processing effect. Under the optimal cutting parameters, the results show that: using this processing technology on the EMU axle deep hole machining, the processing quality is better. The inner hole surface roughness achieves Ra0.8 μm and the hole straightness is 0.13mm/m. Both are able to reach the processing requirements. This paper can provide a certain reference value for the simulation of deep hole drilling and the the deep hole processing of EA4 T steel.