Study On Ultrasonic Cutting Technology Of SiO₂ Aerogel

SiO₂ aerogel is a kind of reinforced fiber composite material with high porosity,high specific surface area,low thermal conductivity,low density and other excellent features.Its thermal insulation function is widely used in construction,aerospace,daily life and other fields,and the demand for aerogels is also increasingly complex and diversified.Currently a variety of aerogel products are prepared directly,in the sol to gel process,pour into a specific mould gelcasting,this preparation method is complicated and costly.In addition,aerogel has the special pore structure,brittle and low intensity,using ordinary machining methods can not avoid the fragmentation of aerogel material,damage,dust and other issues.Based on the above factors,putting forward using ultrasonic processing of SiO₂ aerogel for the research object,designing a reasonable ultrasonic cutting spindle and acoustic system,and verifying the feasibility of ultrasonic processing of SiO₂ aerogel by testing.The following is the main contents and the conclusions reached:?1?Ultrasonic cutting spindle is designed,with combination of double oscillation axis cutting tool device of cutting machine to complete the five-axis linkage processing,Achieving the diversification of processing technology and improving processing accuracy.?2?Acoustic system with f=20KHz is designed,and doing modal analysis with the acoustic system.Through the analysis of the system displacement vector diagram and the system vibration pattern,getting the conclusion that when the resonance frequency equals 19926 Hz,vibration transmission along the longitudinal of the cutting tool and the amplitude reach maximum,is the best vibration mode.Compared with 20 KHz,the error between the two frequencies is less than 0.5%,which verifies the rationality of acoustic system design and meets the processing requirements.?3?Aimed at the vibration problem of round knife processing,proposed to reduce the lateral vibration in the way of grooving the cutter body.Through the simulation analysis,the natural frequency of the tool after grooving is obviously decreased,and the radial groove frequency is reduced by a greater extent than the latitudinal groove,and the vibration intensity of the tool will decrease with the decrease of the natural frequency.On the basis of the above conclusion,the influence of the number of radial slots on lateral vibration is studied.Respectively,opened in the matrix of 0 to 6 ranging from the number of grooves,the analysis results obtained lateral vibration decreases with the increase in the number of slots.Considering the overall rigidity of a circular knife,the number of notches is not as good as possible.?4?Combined with the properties of reinforced fiber composites,studying the mechanical properties of SiO₂ aerogel.In addition,designing a reasonable method of ultrasonic cutting SiO₂ aerogel,and establishing the ultrasonic cutting force model,and proving that the ultrasonic cutting force is less than the ordinary cutting force from a theoretical point of view.?5?Through the tool amplitude test,verifying the rationality of the acoustic system.Using ultrasonic cutting spindle for SiO₂ aerogel cutting test,combined with the shape of the smear metal and the comparison of the surface quality after machining,verify the ultrasonic cutting SiO₂ aerogel is feasible.