纤维随机分布CFRP高速铣削比能模型与表面质量优化

High Speed Milling Specific Cutting Energy Model of CFRP and Its Surface Quality Optimization Based on Random Fiber Distribution

碳纤维增强复合材料(Carbon fiber reinforced plastics, CFRP)具有高比模量和比强度、耐腐蚀性和良好的刚度等优良特性,逐渐被广泛应用于航空航天、汽车、国防军工及生物医疗等高端装备领域。然而,CFRP材料的非均质性及各向异性致使其加工表面形貌非常复杂且极易产生加工缺陷,严重制约了CFRP结构件的使用寿命、服役性能及安全可靠性。鉴于高速切削技术有利于提高加工效率和控制表面质量,而切削比能是加工表面质量的重要指标,因此,首先通过引入碳纤维分布、切削效应及边缘效应,阐明切削比能的来源及分布,建立CFRP高速铣削的切削比能预测模型,该比能预测模型精度91.19%。然后,采用三维均方根面粗糙度和三维分形维数对表面质量进行定量表征,根据比能分量与表面质量之间的相关性分析,定义了面向表面质量的比能综合评价指标SCEsq和SCEds,提出基于比能的表面质量优化方法。最后,基于非线性回归分析,分析了铣削参数对SCEsq和SCEds的影响,验证了高速切削有利于减少CFRP加工缺陷。

Carbon Fiber Reinforced Plastics(CFRP)has excellent properties such as high specific modulus and specific strength,corrosion resistance and good stiffness.It is gradually widely used in high-end equipment fields such as aerospace,automobile,national defense military industry and biomedicine.However,the heterogeneity and anisotropy of CFRP materials make the surface morphology of the workpiece very complex with processing defects,which seriously restricts the service life,service performance and safety reliability of CFRP structural parts.In view of the fact that specific cutting energy is an important index of machined surface quality,and that high-speed cutting technology is conducive to improving processing efficiency and controlling surface quality.Therefore,the source and the distribution of cutting specific energy are clarified considering carbon fiber distribution,cutting effect and edge effect,and the specific cutting energy prediction model of CFRP high-speed milling is established.The accuracy of the presented model is 91.19%.Then,the surface quality is quantitatively characterized by three-dimensional root mean square surface roughness and three-dimensional fractal dimension.According to the correlation analysis between the specific energy component and the surface quality,the specific energy comprehensive evaluation indexes SCEsq and SCEds for surface quality are defined.The surface quality optimization method based on specific energy is proposed.Finally,based on nonlinear regression analysis,the effects of milling parameters on SCEsq and SCEds are analyzed,and it is verified that high speed cutting is beneficial to reduce the machining defects of CF/PEEK.