The Grinding Removal Mechanism And The Research Of Ultrasonic Elliptical Centerless Gringding Technology Of YAG Crystal

The high-precision processing and manufacturing of high-performance laser crystal has great significance on improving the energy conversion,reducing the volume of lasers.As most of laser crystals are hard and brittle materials,polishing is generally used for processing which is low in efficiency.Therefore,it is important to study new processing methods of laser crystals.In this paper,yttrium aluminum garnet(YAG)single crystal is the research object.The material removal mechanism is researched.A new grinding method for hard and brittle materials micro-cylindrical is proposed,and experimental is excuted.First,the load-depth characteristics,elastic modulus,micro/nano-hardness and fracture toughness of YAG single crystals were obtained by nanoindentation tests.The effects of different normal loads and scratch speeds on the surface morphology,chips and cracks of the scratched YAG crystal were studied.A mathematic al model of the relationship between the normal force and the transverse crack width was established.It is pointed out that the material removal mechanism during YAG single crystal grinding is the combination of plastic removal and brittle removal.Secondly,a 28 KHz transducer was designed and manufactured.The finite element simulation was used to analyze the transducer mode.The structure of ultrasonic elliptical vibration system are designed.The influence of different factors on the elliptical vibration generated was studied.The vibration state of the ultrasonic elliptical vibration system is detected.At last,an ultrasonic elliptical vibration centerless grinding experiment platform was designed and constructed to conduct grinding experiments on 1m m YAG single crystal micro-cylinders.Orthogonal tests were designed to study the influence of different factors.A method for improving the processing quality is proposed.By comparing the grinding quality of ultrasonic elliptical centerless grinding and ordinary centerless grinding,the role of ultrasonic elliptical vibration in material removal process was analyzed.