Study On Non-contact Power Transfer Technology Of Rotary Ultrasonic Machining

Rotary ultrasonic machining technology is the combination of traditional machining and ultrasonic machining.Compared with traditional machining,rotary ultrasonic machining has many advantages,such as less cutting force,less cutting heat,better accuracy and efficiency.It is wildly used in machining of hard and brittle materials such as Si,ceramics,hard alloys and composite materials.In rotary ultrasonic machining,the cutting tool is rotating with the spindle.Therefore,the ultrasonic signal produced by the power supply can not be transferred by wire.There are two solutions in solving this problem,i.e.contact power transmission and non-contact power transmission technology.The contact power transmission use frictional contact with a carbon brush and slip ring.This method is easy to achieve but there are lots of problems,such as fast wear,high heat,sparks and poor contact.Previous researchers had used non-contact power transmission technology based on the theory of electromagnetic coupling.This technology can overcome the shortage of contact power transmission.This paper introduces the non-contact power transmission using in rotary ultrasonic machining system.The main contents are as follows:(1)We established the mutual inductance equivalent model of non-contact transformer and the equivalent circuit of vibration unit were introduced.Based on this model,different primary and secondary matching circuits were put forward.(2)The FEM model of non-contact power transformer was established and finite element analyze was made using ANSYS.We analyzed the distribute of Magnetic induction intensity and power transmission efficiency of the system.And an experiment was conducted to make sure the analysis was reliable.After that,the simulation results were used to help design proper structure of non-contact power transmission system according to the real need.(3)We established a rotary ultrasonic machining system using the non-contact power transmission system designed before and carried out three comparison experiments of drilling deep holes in polarization maintain fiber preforms using this system.The scheme,tools and phenomenon of this experiment were detailed.Finally,deep holes with a diameter of 8mm and depth of 250 mm were machined successfully with required accuracy and efficiency.This experiment proved that the non-contact power transmission structure we designed can be used in actual machining.