Research On Single Excitation Longitudinal And Torsional Composite Ultrasonic Vibration Assisted Drilling Of High-Volume Fraction SiC_p/Al

Nowadays,hard and brittle materials are widely used.It is often necessary to process a large number of holes.However,hard and brittle materials will produce fracture characteristics under only a small deformation due to the material properties of the high hardness and poor toughness.So it is difficult to achieve high-precision processing,which restricts the application of hard and brittle materials.In order to improve the processing quality and realize the efficient processing of hard and brittle materials.The paper analyzes the advantages of longitudinal-torsion composite ultrasonic vibration assisted drilling.The amplitude and longitudinal-torsion ratio are changed by designing the amplitude horn with different parameters.The effects of different amplitude and longitudinal-torsional ratio on the edge collapse at the entrance of the hole,the edge collapse at the exit of the hole and the surface quality of the hole are analyzed.The research work of this paper includes the following aspects:(1)Based on the principle of mode transformation,the design principle of a single excitation longitudinal torsional composite ultrasonic vibration assisted drilling device is introduced.The characteristics of high-speed cutting and intermittent cutting of the drill tool are studied by analyzing the motion path.And the conditions for realizing intermittent cutting are theoretically deduced.(2)The paper designs the single excitation longitudinal and torsional composite ultrasonic vibration assisted drilling device.And the parameters of the horn are defined.The influence of the spiral groove parameters of the horn on the resonance frequency and the ratio of longitudinal and torsional amplitude is researched by means of modal analysis and harmonic response analysis.The device performance is detected by a laser displacement sensor.(3)The finite element simulation technology is used to establish the simulation model of longitudinal-torsion composite ultrasonic vibration assisted drilling in ceramic materials.The paper analyzes the drilling process by simulating the traditional drilling,longitudinal vibration assisted drilling and longitudinal-torsion composite ultrasonic vibration assisted drilling respectively.(4)The high-volume fraction SiC_p/Al is drilled by conventional drilling,longitudinal vibration assisted drilling and longitudinal and torsional composite vibration assisted drilling respectively.The different characteristics of the three processing methods on the edge collapse at the entrance of the processing hole,the edge collapse at the exit of the processing hole,and the roughness of hole are studied.(5)The paper designs an orthogonal experiment which has three factors called the spindle speed,feed speed,and amplitude horn.Orthogonal experiments are designed to research the effects of the three factors on the edge collapse at the entrance of the hole,the edge collapse at the exit of the hole,and the roughness of the hole in the longitudinal and torsional composite ultrasonic vibration assisted drilling.In this paper,the longitudinal and torsional composite ultrasonic vibration assisted drilling device is used to drill SiC_p/Al.The experimental results show that under the same conditions,the longitudinal and torsional composite ultrasonic vibration assisted drilling can get best processing quality.In the test of longitudinal torsional composite ultrasonic vibration assisted drilling,using the amplitude horn of a longitudinal torsional amplitude ratio of 1.74 can get the best machining quality.With the increase of spindle rotation speed,the surface roughness of the inner wall of the drilling hole decreases first and then increases.With the increase of feed speed,the surface roughness of the inner wall of the drilled hole increases.