仿生微坑—槽复合织构陶瓷刀具硬车削性能研究

在金属加工中,切屑一般被当做固体进行研究。有研究表明,切屑具有类似于流体的特性,因此,刀—屑接触处于固体与固体接触和固体与流体接触的混合状态。为改善刀具切削性能,综合考虑刀具与切屑接触的混合状态以及切屑流动方向,本文基于蜣螂表皮和鲨鱼表皮,在陶瓷刀具前刀面设计加工了微凹坑织构(DT)、微沟槽织构(GT)和微坑—槽复合织构(DGT)。通过有限元仿真和车削试验,研究了不同切削速度下干式车削GCr15淬硬轴承钢时织构对于刀具切削性能的影响规律。研究表明:三种织构刀具有效改善了陶瓷刀具的切削性能;微坑—槽复合织构刀具(DGT)在不同切削速度下切削性能均为最优;微凹坑织构刀具(DT)在较低切削速度时表现出相对良好的减摩特性,适合于较低的切削速度;微沟槽织构刀具(GT)更适合于较高的切削速度。

Study on Hard Turning Performance of Bionic Micro-dimple-groove Composite Textured Ceramic Cutting Tools

Chip which arises in the cutting process is usually considered as solid.However,some researches indicates that chip also has fluid-like properties.The.contact area between cutting tool and workpiece contains both solid-solid and solid-fluid contact conditions.Taking the hybrid contact condition and chip flow direction into consideration,micro-dimple texture (DT),micro-groove texture (GT)and micro-dimple-groove composite texture (DGT)are fabricated in the ceramic tool rake face by learning from the skins of dung beetle and shark.These ceramic tools are prepared for improving tool performance.Finite element simulation and turning tests are performed,to study the effects of different textures on tool performance at varying cutting speeds in dry turning of GCr15 hardened steel.It is found that all the three kinds of texture on the tool rake face can be utilized to improve ceramic tool performance.Ceramic tool with micro-dimple-groove composite texture (DGT)exhibits the best cutting performance for different cutting speeds.When cutting speed is relatively low,micro-dimple textured ceramic tool (DT)can be used to efficiently reduce the friction between tool and chip.Conversely,micro-groove textured ceramic tool (GT)shows better performance when cutting speed is relatively high.