Simulation And Experimental Research On Ultrasonic Vibration Microdrilling Of SiCp/Al Composite

SiCp/Al composite materials have been widely used in aerospace,medical equipment,electronic components and precision instruments in recent years because of their high specific strength and specific rigidity,excellent dimensional stability,and good electrical conductivity.With the development of science and technology,the continuous production of small equipment has prompted SiCp/Al composite materials to be processed into smaller parts.These tiny parts contain many micropores.Therefore,micropore processing on SiCp/Al composite materials has become new.Technical difficulties.Due to the hardness and brittleness of the SiCp/Al composite material and the low strength of the micro-drill,the traditional drilling is prone to tool wear and collapse when performing micro-hole drilling on the material,which seriously affects the hole processing quality,processing efficiency and production cost.Based on traditional drilling,ultrasonic vibration is applied in the longitudinal direction,and the ultrasonic vibration micro-hole drilling of SiCp/Al composite is explored through theoretical analysis,simulation and experimental demonstration.The main research contents are:(1)Kinematics analysis and mathematical modeling of ultrasonic vibration assisted drillingThe tool tip point motion of ultrasonic vibration assisted drilling is analyzed,and the dynamic change curve of the corresponding parameters such as cutting speed and intermittent cutting conditions are obtained.A mathematical model of cutting force and torque of micro-drilling SiCp/Al composites assisted by ultrasonic vibration was built.The results show that: ultrasonic vibration assist is not a sufficient condition for intermittent cutting.Continuous cutting still exists under ultrasonic vibration conditions;The motion state of the blade has a greater influence.(2)SiCp/Al composite cutting simulation modeling based on ABAQUS / ExplicitA two-dimensional two-phase cutting simulation model is established for points on different positions of the micro-drill edge to explore the changing trend of cutting force at different positions of the blade;the effect of cutting thickness and cutting speed on the cutting force is analyzed by simulation;the material after processing is observed The changes that occurred have explored the effects of ultrasonic vibration-assisted drilling and conventional drilling on SiC particle processing.The results show that the cutting force of the transverse cutting edge is large and the cutting force of the main cutting edge is small during the drilling process;in the ultrasonic vibration assisted cutting state,the SiC particles are mainly broken by particles,and in the traditional cutting state,the SiC particles are mainly broken by particles.Establish a homogenized three-dimensional model of SiCp/Al composites,rely on the three-dimensional model to analyze the effects of speed and feed on the axial force and torque of the drill bit,and analyze the reasons for the impact.The results show that at a frequency of 20,000 Hz and an amplitude of 3 μm,in order to achieve better processing results,the speed and feed should not be too large.(3)Under different rotation speeds and feed conditions,the traditional drilling and ultrasonic vibration assisted drilling experiments of SiCp/Al composite materials were conducted using a Φ0.9mm twist drill,and the correctness of the model was proved by the combination of three-dimensional simulation results.The processing method of combining reaming drilling with ultrasonic vibration assisted drilling is proposed,and four working conditions,including traditional drilling,reaming drilling,ultrasonic vibration assisted drilling and ultrasonic vibration assisted reaming drilling,are tested.Results The reasons for the difference in axial force,tool wear and machining quality under various working conditions were analyzed to obtain a better combination of machining parameters.The results show that ultrasonic vibration-assisted reaming drilling can reduce chipping and improve hole wall quality compared with other working conditions.