Research On The Characterization Of Grinding Surface Roughness Based On Tribological Characteristics

Since the 21 st century,with the rapid development of science and industrial technology,all kinds of high-tech fields require higher parts processing quality and efficiency.Roughness detection forms of various precision devices have been changed from traditional sampling inspection to mandatory inspection,which puts forward higher requirements on the measurement speed of roughness.Grinding is an important part in the processing of precision components,it is of great practical significance to achieve in-situ detection of the surface roughness for the processing efficiency during grinding.Surface roughness in-situ detection requires high efficiency,low cost and strong anti-interference ability.At present,on the one hand,the non-contact measurement represented by optics measurement devices and the contact measurement represented by stylus profilometer are still limited.On the other hand,the existing surface roughness measurement methods are generally applicable to the detection of the external surface,and the research of the internal surface roughness measurement remains to be developed due to the complexity of the measurement environment.So,it is of great practical significance to study an economic and efficient in-situ detection method,especially for the surface roughness of the inner cavity.In this paper,the hard and brittle materials(quartz and monocrystalline silicon)and metal materials(45 steel)commonly used in the grinding field were taken as the research objects.Based on the tribological characteristics,the characterization of the surface contact stiffness,adhesion,sliding friction on the surface roughness and texture was studied.The main research contents of this paper are as follows:(1)A model for the contact stiffness of rough surface based on the elastic-plastic contact of rough peak was established,and the relationship between the surface roughness and the contact stiffness was analyzed.The measurement conditions for the different orders of roughness based on the numerical simulation analysis of the contact stiffness were analyzed.The results showed that the difference of the surface contact stiffness of different orders of magnitude depended on the measurement accuracy of displacement and force sensor.Finally,a contact stiffness measuring device ensuring the contact interface parallelism was designed and installed,and it is verified that the accuracy conditions of displacement and force sensor for the evaluation of contact stiffness of rough surface.(2)A model of adhesion force considering the influence of external load and multi rough peaks based on the analysis of surface morphology was proposed.The results showed that the adhesion force can reflect the change of roughness obviously under sub-micron roughness scale,and the repeated measurement error of adhesion force was less than 5%.Furthermore,the effects of load conditions such as holding time,load,loading rate and unloading rate,temperature,humidity,media between contact surfaces and parallelism between contact surfaces on the adhesion were investigated.(3)Based on the relationship between the current and the output torque of the BLDCM,a method of measuring the surface roughness based on the two-point rotating friction was proposed.Compared with the traditional friction measuring device,it had the characteristics of simple structure and rich information.The results showed that the correlation between the motor current signal and the surface roughness fits well,which was 0.9987.And the motor current signal had a good mapping relationship with the texture characteristics of hard and brittle material.The feasibility of this method was confirmed.Due to the whole equipment can be set into finger size,it provides a new idea for the measurement of surface roughness and texture,especially for the measurement of inner cavity surface.