Research On Key Technology Of High Speed Rotating Test Machine For Ceramic CBN Grinding Wheel

Ceramic CBN grinding wheel is the most representative product in super hard materials and abrasive products industry,and it is considered as the high performance tool in grinding processes,with high speed and high efficiency,high precision and low pollution etc.The main performance test of the CBN grinding wheel is the rotary strength test,because the consequences of its fa ilure is unthinkable when the grinding wheel is in the course of operation.H igh speed rotary strength testing machine is mainly used in turning test of ab rasive in superhard materials industry,so as to check the rotary strength of t he grinding wheel under the specified test conditions.At present,the ultra hi gh speed rotating test equipment of superhard material grinding tools in our c ountry is still in a relatively backward state.The main reason is that the spin dle system effective load capacity is low and the speed can not turn up.In t he control system,the existing grinding wheel broken identification method ca n not meet the recognition need of super hard grinding wheel broken signal.This project,at the base of the in-depth analysis of ceramic CBN grinding w heel rotation test principle and functional requirements,from the perspective o f the design of mechanical spindle system and the detection of wheel broken signal,plans to investigate into the key technology of ceramic CBN grinding wheel.Based on the independent design of the spindle system,this paper makes an in-depth study on the selection,installation and bearing stiffness of the s pindle bearings.Using Hertz theory to calculate the preload,this paper gets t he conclusion that the increase of preload can not only improve the stiffness of the bearing by using MATLAB programming software,but it also can imp rove the static stiffness and critical speed;the spindle speed will improve the bearing radial stiffness decreases,the axial stiffness increases,while preload and stiffness of bearing are balanced.By using the theory of finite element a nalysis,based on the ANSYS software,this paper establishes the model of th e spindle,delves into the spindle static and dynamic characteristics,and into the spindle stiffness and stress characteristics.The paper also determines thenatural frequency of the spindle,the main vibration mode and resonance freq uency.Minimum spindle deformation and dynamic response of natural frequen cies,and the frequency of spindle harmonic are obtained.The paper verifies the rationality of the structural design of the spindle system.In order to improve the accuracy of signal recognition of broken grindin g wheel,this paper probes into the broken characteristic features,ceramic CB N grinding wheel vibration mechanism,and the signal features.Combined wit h the principle,the characteristics,processing method of acoustic emission sig nal,with ordinary wheel acoustic emission characteristics as the basis,the res earch obtains the non Gauss signal characteristics of broken wheel.Based on the experimental design,the experiments were carried out on the ceramic C BN grinding wheel in the spindle system,using the Time domain analysis me thod of AE signal,compare the after-broken wheel with before-broken wheel‘s voltage amplitude diagram,energy and waveform acoustic emission signal.The results show that the characteristic of AE signal were changed by wavef orm and AE the signal changed from the stable and continuous signal into a continuous signal burst conclusion.By using FFT algorithm,wavelet transfor m,the paper verifies that the AE signal conforms with symlet wavelet functi on symmetry,finds changes of characteristics in the ceramic CBN grinding w heel broken and concludes the changes of the AE signal to the high frequenc y region in the frequency domain,and that the wheel after broken will produ ce a high frequency voltage signal.The results showes that the stability of sp indle system independently designed has achieved the desired effect;and acou stic emission technique outperforms the commonly used photoelectric method,volume method and vibration method,so that it is more suitable for the gri nding wheel breakage test recognition area.