| Grinding burn of gear tooth surface affects the performance and service life of gears,which is a key factor to restrict the precision grinding quality.The research of gear grinding burn has important theoretical and engineering application significance for ensuring the quality of products and improving the production efficiency.Magnetic Barkhausen noise(MBN)technology has attracted extensive attention and became a hot area of research in the field of gear grinding burn detection because of the advantages of fast speed,high sensitivity,easy to operate and nondestructive testing.In recent years,analysers developed based on the principle of MBN technology have been applied gradually on surface grinding burn detection of components.However,MBN method itself only produces relative results that need to be compared with calibration blocks to define certain limits for rejection.Besides,there has been no evaluation standard about gear grinding burn detection so far.As a result,calibration research is required to calibrate the instrument and set the reject limit of grinding burn detection before using this method.The research of gear grinding burn has important engineering,and threedimensional surface roughness measurement is a research hotspot.Innovatively,the work applied three-dimensional surface roughness measurement to gear grinding burn detection and revolved around MBN detection principle and system,three-dimensional surface roughness analysis,the process design and the optimization of processing scheme.The method of Nd: YAG laser irradiation on the surface of the samples and slowly cooling in the air was used to produce controllable artificial thermal damage to simulate grinding burn caused by instantaneous high temperature in grinding zone.First,Laser processing parameters like voltage,laser duration and defocusing distance were adjusted in order to produce calibration samples and controll the degree of thermal damage.The degree of laser thermal damage was graded according to the change of surface colors after burn.The results were proved to be much better when the voltage was controlled at the range of 600-700 V and the laser duration was 5-7ms after optimization.Second,the development history of three-dimensional surface roughness,parameters definition,measurement methods and its application were comprehensively introduced,and the three-dimensional parameters defined by ISO 25178 were applied to characterize gear burn.The optimal parameter setting and the correlation of three-dimensional surface parameters in the characterization of burn were analyzed,making it clear in choosing parameters for the characterization of surface burn.Besides,the changes of three-dimensional surface roughness after grinding burn were revealed,and the relationship among areal surface parameters,magnetoelastic parameters of MBN method and laser processing parameters were also studied.It was proved that Sq、Sa、Sxp、Smc、Vv、Vvv、Vvc、Vmc、Sal、Str、Std、Ssk、Sku and Vm(Vmp)were helpful for characterizing gear grinding burn.Last,the testing principle and influence factors of MBN technology were emphatically analyzed,and the optimal excitation voltage was confirmed to be 8V and the excitation frequency was 200 Hz.In addition,Max、Min、Avg、Max/Min、Max/Avg、Min/Avg 、(Max-Min)and Dev were obtained and the limitation of rejection or acceptance was further concluded to be 51.The innovation of this work is the application of three-dimensional surface roughness in the characterization of the gear surface burns and the relationship between laser processing parameters and three-dimensional parameters is analysed to select the relatively sensitive parameters.Subsequently,the conclusion can be helpful for the characterization of grinding burn,which offers a new way for the detection of gear surface burn and finally promotes the application of Barkhausen noise detection technology in the field of nondestructive testing. |
PDF Full Text Request