Optimization Design And Experimental Research On The Drill Bit Part Of The Integrated Tool For Drilling,reaming And Countersinking

In the application scenarios of aircraft wings and skins,titanium alloys and aluminum alloys have been widely used due to their excellent physical and mechanical properties.In the assembly of wings and skins,riveting is the most common connection method.Therefore,there is a large demand for the processing of aluminum alloy and titanium alloy countersunk holes.Compared with the traditional step-by-step hole making,the integrated tool for drilling,reaming and countersinking has the advantages of high efficiency and high precision when processing countersink holes,but at the same time there are disadvantages such as difficult control of drilling exit burrs and easy wear of the tools.In response to the above problems,the optimization design of the integrated tool for drilling,reaming and countersinking is carried out.The main research contents of this thesis are as follows:In this thesis,a three-dimensional model of the integrated tool for drilling reaming,and countersinking is established.Through the analysis of the structure and angle of the drill bit,combined with engineering experience,the main angle parameters that affect the cutting performance of the integrated tool are determined:helix angle,apex angle,and relief angle.The finite element simulation of the uniform cutting process during drilling is carried out,and the feed force,tool temperature,torque,tool stress and other aspects are analyzed,and it is found that a larger point angle can help to increase the life of the tool.The formation process of the exit burr is simulated,and it is found that when the point angle is small,the stress on the drill cap is more concentrated,resulting in transient burrs;when the point angle is large,the stress on the drill cap is distributed more uniformly,resulting in uniform burrs.The helix angle and the relief angle have little effect on the burr shape.Aiming at the removal of the drill cap,the original structure of the integrated tool is improved,and finally a double-point-angle drill with a first point angle of 110° and a second point angle of 140° is designed.The original designed integrated tool,the integrated tool with optimized angles,and the integrated tool with double point angles after optimized structure are prepared,and the cutting performance verification experiment is carried out.The results show that the double point angle integrated tool has better performance in cutting force,burr height,and chip morphology,and the performance of the three tools is very close in terms of hole wall roughness.Through the wear test,the results show that the tool durability after structure optimization is the best.