Study On Ultrasonic Vibration Assisted Drilling Of Three-point Drill For Cortical Bone Damage

With the continuous advancement of medical technology,people begin to pay attention to how to minimize the harm to patients and the recovery period becomes shorter on the basis that surgery can achieve therapeutic effects.Bone drilling plays a very important role in surgery.During the drilling process,irrational drilling parameters can easily lead to thermal damage or even bone necrosis and changes in bone strength.Research shows that ultrasonic vibration drilling can effectively reduce the axial force during drilling and reduce the drilling temperature.Therefore,this paper applies ultrasonic vibration drilling technology to bone drilling.According to the characteristics of the bone structure,three-point drills were used as drilling tools for experimental research.The parameters affecting the axial force and drilling heat were determined by the grey correlation degree,and a single factor experiment was designed to determine the influence and rules of the drilling conditions on the quality of bone drilling through the measurement of biological indicators.The specific research content is as follows:(1)The kinematic characteristics of ultrasonic vibration drilling are analyzed,and the causes of chip breaking are analyzed from the perspective of mechanics and geometry.The theoretical analysis explains why ultrasonic vibration-assisted drilling can reduce the axial force,reduce the drilling temperature,and improve the drilling quality.The drilling form of the three-point drill was analyzed.(2)The tests of Ultrasonic Vibration Twist Drilling(UACD)and Ultrasonic Vibration Three-point Drilling(UATD)were performed by comparing axial force,maximum temperature at the entrance,accuracy of the diameter of the drill hole,and surface roughness of the inner wall of the hole.It is determined that the drilling effect of the three-point drill is indeed better than that of the twist drill.And it proves that the three-point drill has better centering effect than the twist drill.(3)An ultrasonic vibration-assisted three-point drill drilling test platform was established,and the correlation between the spindle speed,feed amount,amplitude,and vibration frequency,and the axial force and the average temperature at the entrance were explored through gray correlation analysis.(4)Prepare cortical bone specimens by controlling the presence or absence ofultrasonic vibration and different feed conditions.A three-point bending test was performed on the cortical bone specimens.By studying the changes in load and deflection under different drilling and vibration conditions measured by the three-point bending test,the changes of bone tissue strength in the drilled area of ?cortical bone specimens were studied.(5)Prepare cortical bone specimens by controlling the presence or absence of ultrasonic vibration and different vibration frequency conditions.Histopathological analysis was performed on the cortical bone specimens,and the rules of thermal damage of bone tissue under different conditions were analyzed by histopathology.