Monitoring The Condition Of Drilling Tools For Carbon Fiber Composite Materials

Carbon fiber reinforced plastics(CFRP)has been widely used in aerospace and civil industrial equipment fields because of its advantages such as high specific strength,the quality of light,and easy to design and shape.However,it is its designability that makes the carbon fiber composite laminated structure have anisotropy,which leads to lamination,tearing,burr and other defects in the processing of the structure,and then seriously affects the quality of the hole wall and the precision of the hole making,so that there are potential risks in the stability and safety of the component.When cutting composite materials,the cutting state of cutting tools is closely related to the machining quality of composite materials.Therefore,through monitoring the cutting state of cutting tools,the monitoring of drilling quality can be realized,and the technical bottleneck restricting the wider use of carbon fiber composite materials can be solved,which will be helpful for its better promotion in aerospace,rail transit,intelligent robot and other high-end manufacturing fields Application.This paper mainly includes the following aspects:(1)This paper studies the cutting mechanism of carbon fiber composite material when drilling,expounds the types and causes of drilling defects caused by wear and other factors,and analyzes the relationship between cutting force and drilling quality.Based on the micro structure characteristics of the tool and drilling principle,the micro-drilling mechanical model of the tool is established,and the wear mechanism of the tool is studied according to the established mechanical model research.(2)The tool condition monitoring system is built and the functions of each component are analyzed to realize the monitoring of drilling axial force and strain.Based on the built monitoring system,the experimental research is carried out,the experimental scheme is designed,the experimental links are optimized,and the data collection is realized.Compare the image quality of different lighting modes of machine vision,optimize the lighting mode and complete the shooting of the quality of CFRP drilling outlet.In this paper,the wear of cutting tools is measured by using the Keyence ultra-depth of field microscope,and the relationship between drilling quality and cutting tool state is explored.(3)The influence mechanism of TiAlN coating tool grinding on improving the drilling quality of CFRP was studied.The micro-morphology of the tool before and after grinding was observed by the ultra-depth of field microscope and the corresponding drilling strain signal processing was analyzed.The reason of improving the drilling quality after grinding and the characteristics of strain frequency signal were revealed.(4)The relationship between the peak value of axial force and tool wear is established by analyzing the time-domain signal of drilling axial force.Through further processing of time-frequency data,the correlation between the statistical characteristics of strain and wear is obtained,In the frequency domain,the main and side inhibition ratio,the main peak valley ratio of wear characterization factors are constructed,and the change rule of tool wear under different conditions is obtained,which serves for the prediction of tool wear state.