Research On Multi-scale Wear Of Diamond Coated Tools In Cutting Of CFRP

Carbon fiber reinforced plastic matrix composites have become the material of choice for reducing weight and increasing efficiency of high-end equipment in the fields of energy and transportation,due to its outstanding advantages such as high specific strength and modulus,and designable performance.Cutting is currently the main method used to machining CFRP for high-end equipment.However,cutting high strength and stiffness fiber is highly susceptible to severe tool wear.The problems of easy tool wear,increased workpiece damage caused by wear,and frequent tool changes are still prominent,which seriously restrict the continuous and stable machining of such large-sized CFRP components.In response to the shortage of basic research on diamond coated tool wear,the multi-scale wear of diamond coated tools in cutting of CFRP is carried out in this paper.The main research contents are as follows:Firstly,the model of the diamond tip scratching along the carbon fiber was established by using molecular dynamics(MD)method.The conditions for determining the bonding and bond breaking between atoms were clarified.The motion trends of carbon fiber atoms during scratching were obtained.The mechanical interlocking and interfacial chemical bonding at different positions of the diamond tip were summarized.Then,the nanoscale failure form of diamond was revealed.And analyzed the wear process of diamond tip from several aspects such as wear rate,number of wear atoms,and wear area.Secondly,CFRP turning experiments were designed and conducted.Microscale tool-workpiece interactions were analyzed based on the CFRP cutting mechanism.By observing the surface morphology of the tool,the main threat of coating peeling was identified.The microscale failure form of diamond coated tools was revealed.In addition,the rationality of the molecular dynamics’ simulation was verified by the phenomenon of diamond structure transformation in the experiment.Finally,the effect of tool wear on chip formation process and cutting force was analyzed.In order to improve tool life and machining efficiency,the influence of coating grain size and cutting speed on tool wear and cutting process was explored,based on the multi-scale tool wear analysis in the previous paper.Related research results help to enrich the basic research on wear of diamond coated tools.It is a reference value for improving the performance of such tools and achieving high quality and efficient machining of large size and high performance CFRP components.