The Design Of The Hollow And Multi-step Longitudinal Vibration Horn With Large Amplitude Ratio

At present,due to the growing demand and processing,the application of ultrasonic in life is becoming more and more widespread.As a means of modern processing,power ultrasonic technology is so favorite.Compared with traditional processing,power ultrasonic technology is shortened the processing time obviously and improve the efficiency,also can overcome the disadvantages of traditional processing and improve the machining quality of work piece.Especially,it has solved many important problems in the field of hard brittle materials and intractable materials and aerospace materials.Ultrasonic vibration system is an important component of the power ultrasonic processing equipment,its design is still the hot spots in research.The transducer,the horn and the tool head is the main components of ultrasonic vibration system.Ultrasonic horn is also known as ultrasonic gear lever or ultrasonic shaped horn.Its main effect is gather mechanical energy and magnify mechanical amplitude and match mechanical impedance in the ultrasonic vibration system,etc.In the actual design,the actual use situation and various performance parameters need to consider.According to different application or pursuit of some performance parameters,the scholars design a lot of different kinds of horns.For example,in the process of drilling at the ultrasonic assisted honing,in order to obtain good cooling and chip removal effect,it need to design a kind horn with the inner hole.Ultrasonic vibration drilling deep holes machining and deep cavity machining and large area machining is generally used the stepped horn.But due to its shaped,the stepped horn can produce stress concentration in loading process,and it is need to come up with a way to solve the stress concentration.In this paper,we study the exponent horn with inner hole,at the same time considering the processing cost,it provide a method to solve it.And in order to reduce the problem of the area mutation,we design a new type of transition section which is a multi-step transition,it reduce the manufacturing cost and the requirement of processing equipment and increase the mechanical strength,at the same time guarantee the amplification coefficient.In this paper,the exponent horn with inner hole and multi-step transition horn is study,calculate and analysis performance parameters for the and compares it with other horns.The detail is as follows:(1).It studied an exponent ultrasonic horn with a cylindrical and a conical hole.Based on the analytical method,the performance parameters of horns are calculated.Using finite element method,the distribution of stress and displacement along the axial are studied,and compared with the traditional exponent horn.The results show that under the same resonant frequency and area factor,the amplification factor of traditional horn is less than the exponent horn with inner hole,exponent ultrasonic horn with a conical hole is largest among them.So it is the shape factor.And amplification factor of the exponent horn with a conical hole is 15%higher than the step horn,and with a cylindrical hole is close to a traditional step horn.It found the hollow’s is larger than the traditional horn.Finally,the sum of the Coordinate values of the node and strain maxima is substantially equivalent to its half wave resonant length.(2)In order to low the processing cost of exponent horn with an inner straight hole,satisfy the actual application requirements under the stress and purse the larger amplification coefficient,an exponent horn with an inner straight hole is changed into the one through bolted connection of several divided segments with holes in this paper.The frequency equation and the formula of the amplification coefficient of the modified horn are derived.Based on finite element method,distribution of the stress and the displacement along the axis of the horn are studied.The results show that under the same resonant frequency and geometrical dimension,the amplification coefficient of the modified horn is larger than the solid one,and slightly less than the one with an inner straight hole.Furthermore,the stress distribution curve is smoother.It is expected to apply to the actual ultrasonic machining.(3)In order to low the processing cost and reduce the stress at the transition of the stepped horn,a new multi-step ultrasonic horn is designed.The frequency equation and the formula of the amplification coefficient of the horn are derived.Based on finite element method,distribution of the stress and the displacement along the axis of the horn are studied.The results show that by compared with traditional stepped horn,the amplification factor of the mult-stepped horn is slightly change,and the decrease of the peak of stress relative value is obvious.Compared with the stepped horn with conic and the circular arc transition section,the amplification factor and the peak of stress relative value are basically same.