不同材质刀具在7075铝合金高速铣削中的磨损研究

Study on the Wear of Different Materials Cutting Tools in High Speed Milling of 7075 Aluminum Alloy

为了研究7075铝合金高速铣削中不同材质刀具的磨损与选用,采用化学气相沉积法((CVD)制备微米(MCD)/纳米(NCD)金刚石涂层刀具,利用场发射扫描电镜观察膜层的表面形貌,结合拉曼谱仪分析CVD金刚石涂层刀具薄膜的结构和成分;分别采用同规格尺寸的硬质合金刀具、MCD涂层刀具在无润滑干切条件下,进行粗加工高速铣削试验,观测两种刀具在加工一定距离后的磨损状况;分别采用同规格尺寸的硬质合金刀具、MCD涂层刀具、NCD涂层刀具在无润滑干切条件下,进行精加工高速铣削试验,观测和分析工件精加工铣削后的表面粗糙度值。结果表明:在大切深高速粗加工铣削7075铝合金时,MCD涂层刀具的寿命为硬质合金刀具的3倍;在小切削深度大进给的高速精加工7075铝合金中,三种刀具铣削后的工件表面粗糙度平均值分别为0.981、1.122和0.960μm,NCD涂层刀具的加工效果要优于MCD涂层刀具;同时通过同一材质刀具的粗、精加工试验对比,发现同规格尺寸的刀具在小切深大进给高速精加工中的寿命是大切深大进给高速粗加工寿命的10倍。这说明7075铝合金的粗加工铣削优选MCD涂层刀具,精加工铣削优选NCD涂层刀具。

In order to study the wear and selection of different materials cutting tools in high speed milling of 7075 aluminum alloy,micro(MCD)/nano(NCD) diamond coated tools were prepared by chemical vapor deposition.The surface morphology of the film was observed by field emission scanning electron microscopy. Analysis of the structure and composition of CVD diamond coated tool films were analyzed by Raman spectroscopy. The same size cemented carbide cutting tool and MCD coated cutting tool were used to carry out rough machining high-speed milling experiment under the condition of dry cutting without lubrication. The wear condition of the two kinds of cutting tools after machining a certain distance was observed. In order to observe and analyze the surface roughness of the workpiece after finish milling,the same size cemented carbide tools,MCD coated tools and NCD coated tools were used to finish high-speed milling experiments under the condition of dry cutting without lubrication. The results show that the life of MCD coated tool is three times longer than that of cemented carbide tool when milling 7075 aluminum alloy with large depth and high speed. In the high-speed finish machining of 7075 aluminum alloy with small cutting depth and large feed,the average surface roughness of the workpiece milled by three kinds of cutting tools is 0. 981μm,1. 122 μm and 0. 960 μm. The machining effect of NCD coated tool is better than that of MCD coated tool. At the same time,through the comparison of rough and finish machining experiments of the same material tool,it is found that the life of the same specification tool in small cutting depth and large feed high-speed finish machining is ten times of that in large cutting depth and large feed high-speed rough machining. The results show that MCD coated tool is the best for rough milling and ncd coated tool is the best for finish milling of 7075 aluminum alloy.